Targeting MYC-Driven Cancers: From Oncogenic Addiction to Therapeutic Vulnerability

Abstract

The MYC family oncoproteins, including MYC, MYCN, and MYCL, are potent drivers of tumorigenesis across a broad range of human cancers, frequently linked to aggressive tumor behavior, poor prognosis, and therapy resistance. They function as master transcriptional regulators that orchestrate gene expression programs governing nearly all aspects of tumor development. Despite their pivotal oncogenic role, they have long been considered “undruggable” due to their intrinsically disordered structure, lack of enzymatic activity, and the difficulty of targeting their protein–DNA and protein–protein interactions with conventional small-molecule approaches. Recent advances are beginning to overcome these challenges through innovative molecular strategies that either directly inhibit MYC activity or exploit MYC regulatory networks. Importantly, the first direct MYC inhibitor evaluated in humans, OMO-103, recently demonstrated promising antitumor activity in phase I clinical trials. Indirect approaches have focused on suppressing MYC transcription, translation, or stability by targeting upstream signaling pathways, as well as by exploiting MYC-associated cofactor interactions and synthetic lethal vulnerabilities to improve therapeutic specificity. In this review, we highlight the multifaceted roles of MYC in different cancer types and provide a comprehensive overview of current therapeutic strategies targeting MYC with a particular focus on epigenetic modifiers and metabolic vulnerabilities.

Key Points

MYC dysregulation drives aggressive tumor progression, poor prognosis, therapy resistance, and contributes to immune evasion through transcriptional reprogramming of cancer cells.

The ongoing first-in-man phase II clinical trial using OMO-103, a direct MYC inhibitor, underscores the potential of translating MYC into a viable target for cancer therapy.

Emerging approaches, including indirect targeting of MYC-driven metabolic and epigenetic programs with downstream effects on immune evasion, highlight novel therapeutic opportunities.

The MYC family of transcription factors

The MYC family of oncogenes comprises three paralogues: c-MYC (hereafter referred to as MYC), MYCN, and MYCL. MYC was first identified in the 1970s as the viral oncogene v-myc in the avian MC29 myelocytomatosis virus, where it was shown to drive cellular transformation and induce leukemia and sarcoma in chickens [1, 2]. The corresponding cellular chicken homologue, Myc was subsequently isolated and characterized in 1982 [3]. Shortly thereafter, the human MYC gene was identified as a consistently translocated gene in Burkitt’s lymphoma (BL) [4, 5], followed by the discovery of the two other MYC family members. The human MYCN gene was first identified as amplified in childhood neuroblastoma (NB) [6, 7], whereas MYCL was subsequently found to be amplified or overexpressed in small cell lung cancer (SCLC) [8]. The MYC family of proteins are transcription factors characterized by a carboxy-terminal basic region/helix-loop-helix/leucine zipper (bHLHZip) domain that mediates DNA binding and dimerization, and a transactivation domain (TAD) at the amino-terminus (Fig. 1A). The TAD and central regions contain several highly conserved MYC boxes (MB0, MBI, MBII, MBIIIa, MBIIIb, and MBIV), which define the MYC interactome and are essential for regulating its transcriptional activity.

Fig. 1.

Functional domains of the MYC family proteins and their mechanisms of transcriptional regulation. A Structural organization of the main protein domains across different MYC family members, MAX, and MIZ-1. MB: MYC box; bHLHZip: basic-helix-loop-helix leucine zipper; NLS: nuclear localization signal; BTB/POZ: broad complex Tramtrack bric-a-brac/Pox virus and zinc finger; ZnF: zinc finger. MYC:MAX interactions are mediated by the bHLHZip domains in each protein. MIZ-1 binding to MYC is mediated by a short helical region located between zinc finger (ZnF) 12 and 13 as indicated by the star. B Interactions of MYC proteins with epigenetic modifiers define their transcriptional activity. MYC proteins activate gene expression via direct and indirect interactions with TRRAP, BRD4, HATs, histone methyl transferases (HMTs), histone demethylases (HDMs), and SWI/SNF chromatin remodeling complexes (green). Interactions with the Polycomb repressive complexes, DNMTs, HDACs, HDMs, and NuRD chromatin remodeling complexes drive MYC-mediated gene repression (red). Designed using Biorender.com.

The MYC proteins are pleiotropic transcription factors that have been estimated to control the expression of approximately 15% of the human genome, inflicting diverse intracellular and extracellular pathways essential to normal development and tissue homeostasis, as well as tumorigenesis [9–12]. To activate transcription of their target genes, they bind to their obligatory partner MYC-associated factor X (MAX) through their bHLHZip domains, forming MYC:MAX heterodimers, an essential requirement for MYC function [13, 14]. The MYC:MAX complex binds specific DNA sequences known as E-box elements, which contain the canonical CACGTG motif within promoter and enhancer regions of target genes [15–17]. MYC proteins have been described as global transcriptional amplifiers of active genes [18–20], although later studies suggest that this effect may be indirectly mediated through MYC downstream targets [21, 22]. In addition, the MYC family can also function as transcriptional repressors, often through interactions with specific cofactors such as the MYC-interacting zinc finger protein (MIZ-1) [23–25], DNA and histone methyltransferases, and histone deacetylases (HDACs) [26, 27]. This dual capacity reflects the ability of MYC proteins to interact with a wide range of transcription factors, chromatin-modifying enzymes, and regulatory complexes, enabling both transcriptional activation and repression [28, 29]. Through these interactions, MYC proteins modulate local chromatin architecture and regulate gene expression in a context-dependent manner (Fig. 1B).

In healthy cells, MYC acts as a tightly regulated molecular switch that responds to extracellular growth signals, controlling genes needed for cell division and growth, as well as tissue maintenance, and is essential for normal development, regeneration, and immune responses. Following stimulation by hormones, cytokines, or growth factors, MYC is rapidly induced and activates expression of genes involved in the G1-to-S transition, including cyclins, cyclin-dependent kinases (CDKs), and other regulators of DNA replication [30]. This allows controlled proliferation during tissue growth, wound repair, and immune activation [31]. Importantly, MYC coordinates metabolic adaptations needed for rapid growth by promoting glycolysis, glutamine metabolism, nucleotide, and lipid biosynthesis, as well as mitochondrial function [32]. It further supports anabolic pathways and cellular growth by promoting ribosome production, protein synthesis, and mitochondrial activity [33, 34]. These processes contribute to the biomass required for cell division and are important in high-turnover tissues such as the intestinal epithelium, skin, and bone marrow. MYC also plays a key role in stem cell maintenance, embryonic development, and tissue regeneration [35]. Thus, its expression must be precisely controlled, since dysregulated or sustained MYC activity can block normal differentiation and disrupt tissue homeostasis. Overall, MYC functions as a master regulator of proliferation, growth, metabolism, differentiation, and apoptosis. Its importance in normal biology reflects the need for precise control of cell behavior, while its dysregulation helps explain its key role in cancer.

Soucek et al. genetically modeled both the therapeutic impact and the side effects of systemic MYC inhibition in a preclinical mouse model of RAS-induced lung adenocarcinoma by using inducible expression of the dominant-negative MYC inhibitor OMOMYC. The authors found that MYC inhibition triggered rapid regression of lung tumors, defining an unexpected role for endogenous MYC function in the maintenance of RAS-dependent tumors in vivo. Although systemic MYC inhibition exerted profound effects on normal regenerating tissues, including the gut epithelium, these effects were reversible and well tolerated over extended periods [36].

Importantly, recent results from a phase I clinical trial of the OMO-103 MYC inhibitor in patients with advanced solid tumors showed overall safety and tolerability. The most common adverse events were grade 1 infusion-related reactions, occurring in ten out of 22 patients enrolled. Target engagement was determined by transcriptomic analyses, and a recommended phase II dose was determined [37]. While early clinical experience with OMO-103 as well as some other MYC targeting strategies has been encouraging, the current available safety data remain limited, and further clinical investigation is required to establish the therapeutic window and long-term tolerability of these approaches.

MYC is an intrinsically disordered protein

One of the primary challenges in therapeutically targeting the MYC oncoproteins arises from their structural properties as intrinsically disordered proteins (IDPs) [38]. The AlphaFold generated structure of MYC clearly shows that the protein is predominantly disordered (Fig. 2, left panel). Unlike structured proteins, IDPs lack a stable tertiary structure and do not adopt a well-defined three-dimensional conformation under physiological conditions. Instead, they exist as highly dynamic ensembles of interconverting conformations. This structural plasticity enables MYC to rapidly transition between multiple states, allowing interactions with a diverse array of binding partners as depicted in the AlphaFold generated structure of the full-length MYC:MAX complex (Fig. 2, right panel). Consistent with this property, structural characterization of peptide derivatives from different regions of the MYC TAD demonstrates that they adopt distinct conformations in the bound state. As examples, one peptide forms a fuzzy complex upon binding to protein phosphatase 1 nuclear targeting subunits (PNUTS) [39], whereas another adopts a polyproline II (PPII) conformation when interacting with the tumor suppressor MYC box-dependent-interacting protein 1 (BIN1) [40]. A third peptide forms an amphipathic alpha-helix when bound to a complex comprising the TATA binding protein (TBP) and the amino-terminal domain of TBP-associated factor 1 (TAF1^TAND1) [41]. The amino-terminal region of MYCN was recently reported to form a dynamic fuzzy complex with the N-lobe of protein kinase Aurora-A (AURKA) through two primary binding sites involving the conserved MB0 and MBI motifs [42]. The study also identified a third, relatively weaker binding site that overlaps with an earlier structurally characterized MYCN peptide in complex with AURKA [43]. Importantly, the interaction between MYCN and AURKA was shown to be inhibited by Aurkin-A, a small molecule kinase inhibitor, highlighting the potential for therapeutic intervention. Additionally, a peptide derived from the central region of MYC engages the chromatin-associated tryptophan-aspartic acid (WD) repeat-containing protein 5 (WDR5) in an extended conformation [44]. In contrast, the carboxy-terminal DNA binding domain adopts a bHLHZip architecture upon dimerization with its obligate binding partner MAX, as described above. Collectively, these structural characterizations underscore the pronounced structural heterogeneity of MYC, which makes it particularly difficult to target using conventional structure-based drug-design strategies that typically rely on the presence of stable and well-defined binding pockets. As a result, IDPs such as MYC have long been considered “undruggable.” Notably, it is estimated that approximately 70% of proteins implicated in aberrant cellular regulation in cancer exhibit intrinsic disorder, either within specific regions or across their entire sequence [45]. Consequently, the ability to rationally target IDPs represents a highly compelling frontier in drug discovery. The development of effective strategies to target disordered proteins would substantially expand the druggable proteome and open new avenues for cancer intervention.

Fig. 2.

AlphaFold derived models of MYC and the MYC:MAX complex. Left panel: AlphaFold-generated structure of full-length MYC. The residues of MYC (Uniprot ID: P01106) are color coded based on the predicted Local Difference Distance Test (pLDDT) score. These range from low (red) to high (blue), reflecting regions predicted to be disordered versus ordered in the structure. Adapted from Vosselman et al (111). Right panel: AlphaFold derived model of the full-length MYC:MAX complex. MYC is shown in blue and MAX (Uniprot ID: P61244) in orange.

Deregulation of MYC Family Oncogenes at the Core of the Hallmarks of Cancer

In contrast to many other oncogenes, MYC dysregulation is primarily driven by sustained aberrant activation rather than recurrent genetic mutations. Given its involvement in a wide range of normal cellular functions, uncontrolled MYC expression drives tumorigenesis by facilitating the hallmarks of cancer (Fig. 3). Due to the constitutively high expression, its tight regulation by mitogenic signals is lost, leading to persistent cell cycle reentry, uncontrolled cell proliferation, and overriding of cellular checkpoints that would otherwise restrict cell division [46, 47]. Moreover, MYC promotes ribosomal biogenesis and protein synthesis, thereby enhancing cell growth [29], and was identified as one of the four Yamanaka factors capable of reprogramming differentiated cells into pluripotent stem cells [48]. Although MYC increases the efficiency of cellular reprogramming, it also exhibits tumorigenic potential, suggesting that its role in maintaining stemness is linked to both inhibition of differentiation and induction of malignant transformation [49]. Consistent with this notion, MYC inactivation has been associated with differentiation in many different tumor types, underscoring the phenotypic plasticity of cancer cells. MYC suppression has also been linked to tumor regression through modulation of immune components and the tumor microenvironment (TME), leading to the restoration of normal tissue architecture [50–52].

Fig. 3.

Oncogenic MYC as a master regulator of cancer. Altered MYC expression impacts all hallmarks of cancer. Through direct and indirect mechanisms, the MYC family of oncoproteins orchestrates transcriptional programs that regulate uncontrolled proliferation, cell death, angiogenesis, migration and invasion, cellular metabolism, immune evasion, genomic instability, inflammation, phenotypic plasticity, epigenetic states, senescence, and interactions with the microbiota. Designed using Biorender.com. Adapted from [220].

To sustain rapid cell proliferation, cancer cells reprogram their metabolism to meet increased energy and biosynthetic demands. MYC plays a central role in rewiring energy metabolism by enhancing glycolysis, lactate production, and secretion, and by regulating glutaminolysis and lipid metabolism, as well as mitochondrial content and function [53]. Activation of MYC can also result in genomic instability, including DNA double-strand breaks, chromosomal gain/loss, and whole chromosomal mis-segregation, resulting in tetraploidy or aneuploidy. These effects arise from repression of cell cycle checkpoints, impairment of DNA repair mechanisms, and accumulation of reactive oxygen species (ROS) resulting from increased mitochondrial activity during rapid cell proliferation [54–56]. This genomic stress can, in turn, trigger cell death programs by inducing the expression of pro-apoptotic factors such as Bcl-2-interacting mediator of cell death (BIM) and other BCL-2 homology domain 3 (BH3)-only proteins. Hence, resistance to MYC-driven apoptosis requires increased expression of antiapoptotic factors [57, 58]. MYC can also trigger apoptosis through p53 stabilization via activation of p19^ARF [59]. In addition, bypassing cell cycle checkpoint proteins such as p16 and p21, MYC can prevent senescence. Notably, recent studies have shown that MYC/MYCN form multimers that bind to RNA, which in turn supports S phase progression and tumor cell stress resilience [60, 61]. However, under certain conditions, its overexpression can also induce senescence, highlighting the context-dependent nature of its effects, which are influenced by cell type, genetic background, and additional regulatory factors [62–64].

Furthermore, MYC promotes angiogenesis by regulating the expression of vascular endothelial growth factor (VEGF) [65]. It also enhances cancer cell migration, invasion, and metastasis through transcriptional regulation of epithelial-to-mesenchymal (EMT) transition and extracellular matrix-associated genes, as well as direct effects on cytoskeletal dynamics (via its cytoplasmic truncated form, MYC-nick) [66–68]. Importantly, MYC enables tumors to evade immunosurveillance by regulating inhibitory immune checkpoint molecules, such as programmed death-ligand 1 (PD-L1) and Cluster of differentiation 47 (CD47), as well as cytokines including chemokine (C-C motif) ligand 2 (CCL2) and CCL9. It further reduces the major histocompatibility complex class I (MHC I) expression, reprograms macrophages toward protumor phenotypes, and impairs the recruitment and activation of immune effector cells [B cells, natural killer (NK) cells, as well as CD4⁺ and CD8⁺ T cells]. Further, high MYC/MYCN levels enhance immune evasion by preventing the accumulation of double-stranded (ds) RNA and R-loops-derived RNA-DNA hybrids, which in turn activate immunogenic cell death through the innate immune response [69, 70]. Collectively, these effects contribute to the establishment of a proinflammatory yet immunosuppressive TME [10, 71, 72].

MYC is a central regulator of the cancer epigenome which interacts with multiple chromatin modifiers that remodel chromatin structure in the proximity of its binding sites, promoting gene expression. These include the transactivation/transformation-associated protein (TRRAP), bromodomain-containing protein 4 (BRD4), general control of amino acid synthesis protein 5-like 2 (GCN5), 48/49 kDa TBP-interacting protein (TIP48/49), and histone acetyltransferases (HATs) [26, 27]. Conversely, MYC can also engage chromatin regulators that mediate gene repression such as HDACs, DNA methyltransferases, and Polycomb complexes [26, 27]. Together, these interactions allow MYC to orchestrate diverse gene expression programs that drive tumor initiation, progression, and adaptation to cellular stress and therapeutic pressure.

The microbiome influences cancer development and progression by inducing inflammation and altering immune responses and metabolism within the TME. Although this field is just emerging, several studies have shown a correlation between the microbiota and MYC levels in cancer. For instance, the bacterial protein AvrA in Salmonella enterica induced proliferation and promoted colon cancer development and progression via increased expression of β-catenin and its downstream targets MYC and cyclin D1 [73]. In addition, Clostridium butyricum has been shown to promote proteasomal degradation of MYC, thus overcoming chemotherapy resistance, suppressing tumor growth, and enhancing the efficacy of anti-programmed cell death protein 1 (PD-1) immunotherapy in colon cancer [74]. Given the significant role of MYC in orchestrating virtually all hallmarks of cancer, developing strategies to target this oncogenic driver and its widespread effects remains one central challenge in cancer research.

Strategies to Inhibit the Oncogenic Functions of MYC

MYC proteins function as central regulatory hubs, or master switches, that integrate multiple upstream signaling pathways and control the expression of genes involved in nearly all cellular processes [75, 76]. Aberrant MYC activity drives extensive downstream transcriptional programs that regulate every aspect of tumorigenesis. Importantly, preclinical studies have shown that inactivation of deregulated MYC can induce striking tumor regression without affecting normal physiological MYC function, illustrating the phenomenon of oncogene addiction [50]. Thus, targeting one single key oncoprotein, here MYC, has the potential to collapse MYC-driven malignant programs, providing an attractive therapeutic strategy. However, its targeting remains highly challenging due to a combination of factors, including its intrinsically disordered structure, lack of enzymatic activity, and the difficulty of disrupting its protein–protein and protein–DNA interactions, as extensively reviewed elsewhere [77]. Here, we discuss current approaches to target MYC, including direct and indirect inhibitors, as well as strategies aimed at modulating MYC’s mechanistic functions with particular emphasis on epigenetic mechanisms and metabolic pathways (Fig. 4). We also highlight those interventions showing promising results in preclinical models and emerging evidence of clinical efficacy.

Fig. 4.

Current strategies explored to target MYC-driven tumors. Top panel: Direct approaches to inhibit MYC include small molecules and peptides (mini-proteins) to disrupt MYC:MAX dimerization and subsequent inhibition of DNA-binding and target gene expression, as well as MYC-specific PROTACs driving MYC protein proteasomal-mediated degradation. Middle panel: Most MYC targeting strategies employ indirect approaches such as those based on interfering with the MYC gene transcription, MYC protein synthesis and stability Lower panel: Approaches utilizing synthetic lethal targets involved in cell cycle, epigenetic modifications, and metabolic pathways. Designed using Biorender.com.

Direct Targeting Approaches

Targeting MYC with Mini-Proteins or Peptides

The transcriptional and oncogenic activities of MYC and recognition of the E-box sequences present in the promoter region of target genes depend on its ability to interact with its obligatory binding partner MAX [13]. This heterodimerization stabilizes MYC and enables engagement with a broad network of interactors [78]. Accordingly, one of the most extensively explored strategies to inhibit MYC function involves disrupting MYC:MAX protein–protein interactions. Substantial progress over the past two decades has demonstrated that this binding can be pharmacologically targeted using small-molecule and mini-protein/peptide-based approaches. We only briefly discuss small-molecule inhibitors of MYC:MAX interactions, as these have been comprehensively reviewed elsewhere [79–81]. Early proof-of-concept studies using yeast two-hybrid and biochemical screening identified 10058-F4 and 10074-G5 as small molecules that bind to disordered carboxy-terminal region of MYC and interfere with MYC:MAX heterodimerization, thereby reducing DNA binding and inhibiting MYC-dependent transcription and proliferation in vitro [82]. Similarly, fluorescence resonance energy transfer-based screening identified IIA4B20 and IIA6B17 as inhibitors of MYC:MAX dimerization that suppress MYC-driven oncogenic transformation in chicken embryo fibroblasts [83]. Although these first-generation inhibitors exhibited limited potency, poor metabolic stability, and suboptimal pharmacokinetics that precluded clinical translation, they provided critical proof of principle that transient, dynamic interfaces within intrinsically disordered MYC proteins can be modulated by small molecules. Subsequently, large-scale in silico screening identified MYCi361 as a MYC:MAX inhibitor with improved pharmacokinetic properties [84]. This molecule reduces MYC stability and transcriptional activity and suppresses MYC-driven tumor growth in vivo. Notably, MYCi361 also synergizes with anti-PD-1 therapy, highlighting the potential of combining MYC inhibition with immune checkpoint blockade. MYCi975, an improved analog of MYCi361, with enhanced therapeutic index [85], suppresses cancer cell growth of MYC/MYCN-dependent tumors such as NB, prostate cancer (PCa), lymphoma, and leukemia [84], as well as enhances immunotherapy approaches in in vivo models of PCa and multiple myeloma (MM) [84, 86]. Despite these advances, none of the MYC:MAX small-molecule inhibitors have progressed to clinical application due to persistent challenges related to efficacy, specificity, toxicity, bioavailability, and other limitations.

Although small-molecule approaches have provided important proof-of-principle, therapeutic inhibition of protein–protein interactions are often more effectively achieved using mini-proteins or peptides, which can engage larger binding interfaces on molecular targets with greater efficiency and selectivity than small-molecules. This section summarizes the developments in MYC targeting using these modalities (Table 1).

Table 1.

Mini-proteins and peptide modalities targeting MYC.

Inhibitor	Modality	Stage of development	References
OMOMYC	Mini-protein	OMO-103 derivative in phase 1b/II clinical trials.	[37] NCT04808362, NCT06059001, NCT06650514
HeloMYC	Mini-protein	Inhibition of MYC driven transcriptional activity and cancer cell proliferation in vitro.	[92]
DuoMYC	Mini-protein	Inhibition of MYC driven transcriptional activity in vitro.	[93]
ME47	Mini-protein	Inhibition of tumor growth in vivo.	[94, 96]
MEF	Mini-protein	Downregulation of MYC target genes in vitro.	[97, 99]
MEF/C93	Mini-protein	Downregulation of MYC target genes in vitro.	[99]
STR	Mini-protein	Downregulation of MYC-driven gene expression and inhibition of cell proliferation in vitro.	[100]
MAD	Mini-protein	Inhibition of MYC-driven cell proliferation in vitro.	[101]
IDP-121	Stapled-peptide	Phase I/II clinical trials.	[103] NCT05908409
Mizmetic	Stapled-peptide	Disruption of MYC:MAX complex formation and DNA binding in vitro.	[106]
NT-B2R	Bicyclic peptide	Inhibition of MYC driven transcriptional activity in vitro.	[108]
H1	Linear peptide	Inhibition of MYC driven transcriptional activity in vitro.	[109]
coreMYC	Linear peptide	Conformational switch that regulates MYC protein–protein interactions in vitro.	[110, 111, 112]

OMOMYC

OMOMYC is a 92 amino acid (residues 348–439) mini-protein developed through strategic incorporation of four specific amino acid substitutions (E410T, E417I, R423Q, and R424N) within the Zip region of MYC, which governs dimerization [87]. This rational mutagenesis has allowed OMOMYC to preferentially bind with MAX while also permitting OMOMYC homodimer formation besides direct binding to MYC, thus effectively preventing MYC from interacting with target gene promoters (Fig. 5A, B) [88, 89]. Preclinical studies have shown that OMOMYC can penetrate cancer cells, localize to the nucleus, globally suppress MYC-driven transcriptional programs, and reduce tumor growth across diverse cancer models [36, 89–91]. Importantly, OMO-103, a systemically deliverable formulation of OMOMYC, has advanced into clinical translation. It showed favorable safety with no adverse side effects on normal tissues, efficient target engagement, and preliminary evidence of antitumor activity in a phase I trial (NCT04808362) in patients with advanced solid tumors [37]. Pharmacodynamic analyses confirmed modulation of MYC-related transcriptional and immune biomarkers, supporting further evaluation in phase Ib and phase II trials (NCT06059001 and NCT06650514). Thus, OMO-103 represents the first clinically validated and successfully administered MYC inhibitor (MYCi), highlighting the therapeutic potential of mini-protein strategies against previously intractable targets.

Fig. 5.

Experimentally resolved structures of mini-proteins developed to target MYC. Homodimer of OMOMYC in blue without (A) and with (B) DNA, respectively. (C) Homodimer of ME47 without the DNA. The MAX basic region and the HLH region from the E47 protein are colored in green and pink, respectively. (D) Tetra-helical assemble of the STR-DNA complex. The ligation between the basic region and the Zip derived from MAX is shown in stick representation, colored in yellow. The PDB IDs of all the structures are indicated.

HeloMYC

A protein engineering strategy termed reCHEMbinant, which combines helical stabilization via covalent stapling and sequence-based mutations, was used to generate HeloMYC, i.e., stapled-peptide derivatives of OMOMYC with enhanced physicochemical properties and cellular uptake [92]. The lead peptide (HeloMYC-1421) recognized E-Box DNA with low nanomolar affinity, exhibited significantly enhanced cellular entry, and outperformed OMOMYC in potently inhibiting MYC-driven gene expression [92]. It further showed selective antiproliferative activity in MYC-dependent cancer cells while maintaining low cellular toxicity. This study identified HeloMYC as a promising candidate for therapeutic development and underscores the potential of the reCHEMbinant platform as a useful protein engineering tool to develop intracellular biologics.

DuoMYC

DuoMYC, a miniaturized derivative of OMOMYC, was developed by removing the Zip and covalently linking the carboxy termini of two bHLH monomers with a synthetic linker to create a stable, covalently constrained dimer [93]. This design mimics the OMOMYC homodimer while preserving the functional motifs required for DNA recognition, reducing molecular size. Experimental measurements showed that DuoMYC retains high-affinity binding to MYC target E-box sequences, exhibits efficient cellular uptake, and demonstrates potent inhibition of MYC-driven transcription by competing with endogenous MYC:MAX complexes for promoter occupancy [93]. The reduced molecular weight is expected to enhance pharmacokinetic properties, making DuoMYC a promising next-generation MYCi. This approach also illustrates how strategic protein miniaturization and covalent stabilization can improve the therapeutic utility of MYC-derived inhibitors. Notably, in vivo evaluation of DuoMYC has not yet been reported.

ME47-MEF-MEF/C93

ME47 (originally Max-E47) is a 66 amino acid mini-protein created by fusing the basic DNA-binding region of MAX with the HLH of E47 protein, a member of the bHLH family [94]. Crystallization revealed that ME47 forms a homodimer through the HLH subdomain even in the absence of DNA (Fig. 5C) [95]. Functionally, ME47 binds E-box DNA elements with high affinity and specificity, effectively outcompeting the native MAX bHLHZip for target site occupancy [94]. This competitive binding prevents MYC:MAX heterodimers from engaging target promoters, thereby reducing transcription of MYC-dependent genes. Induction of ME47 expression decreases cellular proliferation and inhibits tumor growth in vitro and in vivo, demonstrating its therapeutic efficacy against MYC [96].

MEF, the next-generation derivative of ME47 [97], was engineered as a hybrid “franken-protein” by combining a double alanine mutant of ME47 (R12A and C29A) with a semi-rationally designed Zip (FosW) derived from the c-Fos Zip domain [98]. This design integrates modules from three transcription factor families: the MAX basic region (b), E47 (HLH), and FosW (Zip). Compared with ME47, MEF exhibits enhanced stability, higher binding affinity, and greater specificity for E-box sequences, illustrating the power of rational design and directed evolution in developing MYC-targeted mini-proteins.

MEF/C93, an additional derivative, incorporates a carboxy-terminal cysteine that allows covalent homodimerization, further improving the stability of the mini-protein. MEF/C93 localizes to the nucleus, has high affinity and specificity to E-Box DNA, and selectively downregulates MYC target genes [99]. However, the disulfide bond may be unstable in the reducing environment of normal cells, although the authors propose that the more oxidizing milieu of cancer cells could confer greater stability to the cysteine-linked mini-protein.

Synthetic Transcriptional Repressors

A chemical strategy was developed to generate modular synthetic transcriptional repressors (STRs) derived from the bHLHZip of MAX [100]. This approach involved the separate chemical synthesis of the basic and Zip segments, stabilization of their helices via hydrocarbon stapling, and ligation to generate a “cross-dimer” structure. Crystallographic analysis of the STR-DNA complex revealed that the synthetic repressor recognizes the E-Box DNA through a tetra-helical assembly (Fig. 5D). The lead STR116 molecule exhibited nanomolar affinity for the E-box motif, directly inhibited MYC:MAX DNA binding, displayed cell-permeable properties, downregulated MYC-dependent gene transcription, and repressed cell proliferation of MYC-driven cancer cells. Importantly, this modular architecture can be reprogrammed to mimic other bHLH transcription factors, highlighting its versatility as a synthetic approach to modulate transcription factor activity [100].

MAD

The MAD mini-protein comprises residues 1–145 of the MAX dimerization protein 1 (MXD1), a cellular MYC antagonist, encompassing both the mammalian Switch-insensitive 3A (mSIN3A) interaction domain (SID) and the bHLH region [101]. Two cysteine residues (C75 and C111) were mutated to inhibit disulfide bond formation, and S145A was introduced to enhance stability by preventing phosphorylation-dependent ubiquitination and proteasomal degradation [102]. MAD is cell-permeable, localizes to the nucleus, and represses MYC activity through three mechanisms: (1) heterodimerizing with MAX for E-Box DNA-binding, thereby effectively blocking MYC transcriptional activity; (2) recruitment of the epigenetic repressor mSIN3A via its SID, further suppressing MYC-driven gene expression; and (3) interaction with upstream binding factor (UBF), which inhibits MYC-activated ribosomal gene transcription.

IDP-121

The first-in-class stapled-peptide inhibitor IDP-121 was rationally designed to specifically target MYC and block its interaction with MAX [103]. Stapled-peptides employ hydrocarbon crosslinks to stabilize α-helical epitopes involved in protein–protein interactions and enhance binding affinity to the target protein [104, 105]. Biophysical and cellular characterization showed that IDP-121 binds MYC with nanomolar affinity, disrupts the MYC:MAX complex, rapidly internalizes into cells, and efficiently localizes to the nucleus. The drug-like properties and antitumor efficacy of IDP-121 were further demonstrated in vivo in solid tumor models. IDP-121 is currently undergoing phase I/II clinical evaluation (NCT05908409), underscoring both its potential as a MYC-targeted therapy and the broader potential of stapled-peptides as inhibitors of protein–protein interactions.

Mizmetic

A protein–protein interaction model between MYC and MIZ-1 was developed using AlphaFold-Multimer [106]. The model predicted that the MID2 domain of MIZ-1 adopts a helical structure and docks at a site on MYC that overlaps with the MAX dimerization interface. Guided by this structural insight, stapled-peptide derivatives, termed Mizmetic, were rationally designed and synthesized. The most potent variant exhibited nanomolar affinity for MYC. Using alanine scanning, the key “hot-spot” residues mediating the interaction were identified, and favorable substitutions were incorporated. The optimized set of stapled-peptides effectively inhibited MYC:MAX complex formation and E-Box DNA binding. Beyond generating lead compounds, the study illustrates how artificial intelligence (AI)-based structure prediction can be systematically applied to design and develop new peptide-based MYC inhibitors.

NT-B2R

Bicyclic peptides have emerged as an attractive class of constrained peptide therapeutics [107]. High-throughput screening of a stereo-diversified bicyclic peptide library against a synthetic epitope from the carboxy-terminal domain of MYC (residues E263–R378) identified a lead compound, NT-B2R, which binds full-length MYC with nanomolar affinity [108]. While NT-B2R was not intrinsically cell-permeable, liposome-mediated delivery enabled cellular uptake and led to significant modulation of MYC-regulated gene expression. Although still at an early stage, this work underscores the potential of conformationally constrained cyclic peptide scaffolds to directly target MYC for developing next-generation therapeutics.

H1 peptide

 The 14 amino acids linear H1 peptide is derived from helix 1 of the bHLH region of MYC, with two amino acid substitutions (S6A and F8A) incorporated to improve the overall helicity [109]. It was designed to inhibit MYC:MAX dimerization and block E-Box DNA-binding. Since H1 is not inherently cell permeable, fusion with the 16 amino acid cell-penetrating peptide derived from the Antennapedia homeodomain of Drosophila melanogaster enables efficient intracellular delivery. Upon cellular uptake, H1 reduced cell survival and suppressed MYC-regulated gene expression, demonstrating its potential as a targeted MYCi, particularly when paired with effective delivery strategies [109]. Further investigations in vivo are warranted to assess the therapeutic potential of this promising compound.

coreMYC

To overcome challenges associated with direct MYC targeting, we performed an integrative study combining computational peptide design, biophysical characterization, and cellular analyses, which led to the identification of a 50-amino acid conformational switch (residues 101–150) within the MYC TAD [110–112]. This epitope, termed coreMYC (COnformational REgulator of c-MYC), exists in a dynamic equilibrium between two distinct conformational states that regulate its protein-binding activity. The extended conformation of coreMYC, characterized by exposed hydrophobic residues, enables binding to MYC interactors that recognize this region of the MYC TAD, whereas the compact conformation, driven by hydrophobic collapse, prevents these interactions. Using the polyphenol epigallocatechin gallate (EGCG) to modulate the conformational structure of coreMYC, we demonstrate that the induction of the closed state inhibits interaction with TRRAP and TBP, both of which are essential for the transcriptional and oncogenic activities of MYC [110]. Our findings establish coreMYC as a functionally important regulatory element and highlight its potential as a conformational switch that can be leveraged to identify compounds capable of shifting the structural equilibrium of MYC toward the inactive compact state. Further, coreMYC itself may serve as a scaffold for the development of peptide derivatives that competitively modulate the MYC protein–protein interaction landscape, offering a promising strategy for therapeutic intervention.

Targeting MYC with PROTACs

Proteolysis-targeting chimeras (PROTACs) are bifunctional small molecules that recruit a target protein to an E3 ubiquitin ligase, inducing ubiquitination and subsequent degradation of the target via the 26S proteasome [113]. Recent studies have provided proof-of-concept that PROTACs represent another potential viable therapeutic strategy in MYC-driven cancers. For instance, the PROTAC MTP3, developed through structural modification of MYC-targeting small-molecule KJ-Pyr-9, effectively depletes endogenous full-length MYC protein, and uniquely induces the accumulation of a functional amino-terminally truncated MYC species [114]. Additional PROTACs, CSI86 and CSI107, which incorporate von Hippel-Lindau (VHL) ligands, have been shown to induce MYC degradation and exhibit antiproliferative activity against breast and PCa cells [115]. These lead molecules also showed encouraging efficacy in vivo, supporting their potential for therapeutic intervention against MYC-dependent tumors. Moreover, two oligonucleotide-based PROTACs have been developed by conjugating a VHL ligand, VH032, with an optimized E-Box DNA sequence [116]. These compounds effectively degrade MYC, suppress cell proliferation in hepatocellular carcinoma (HCC) cells, and significantly reduce tumor growth in vivo. Collectively, these studies highlight the potential of targeted MYC degradation as a powerful means to inhibit MYC activity.

MYC Phase Separation and Therapeutic Implications

Biomolecular phase separation has emerged as a fundamental mechanism for organizing intracellular components through the formation of dynamic, membraneless condensates and regulating diverse cellular processes, including gene expression [117]. In this context, recent studies have begun to uncover the role of phase separation in modulating both the transcriptional activity and other MYC functions [61, 69, 118, 119]. Yang et al. demonstrated that MYCN can form dynamic, transcriptionally active condensates involving both its TAD and DNA-binding interface [118]. These condensates incorporate its dimerization partner MAX, genomic DNA, and components of the transcriptional machinery, including mediator complex subunit 1 (MED1) and RNA polymerase II, as well as nascent RNA [118]. This study further shows that phase separation preferentially modulates a subset of MYCN-regulated genes, indicating that its regulatory effects are selective rather than global [118]. Another study reported that a conserved acidic region within MYC mediates multivalent electrostatic interactions that directly regulate its capacity for phase separation [119]. Deletion or mutation of charged residues within this region alters MYC aggregation behavior and promotes cancer cell proliferation, highlighting sequence-level determinants that modulate MYC condensate formation, aggregation dynamics, and functional activity. MYC has been shown to undergo phase transitions in response to transcriptional stress, forming multimeric, sphere-like structures [61]. A more recent study further demonstrated that the formation of such condensate-like assemblies is associated with a shift in MYC from a DNA-bound to an RNA-bound state [69]. The authors also characterized multiple RNA-binding regions (RBR I–IV) within MYC, where RBRIII exhibits the highest affinity. This RNA-associated phase transition of MYC suppresses the accumulation of immunogenic RNA–DNA hybrids and prevents activation of innate immune signaling pathways [69]. Collectively, these insights have important therapeutic implications, as phase-separation biology is developing as an important avenue for disease intervention [120]. Strategies that selectively disrupt specific condensate functions, such as MYC-cofactor interactions or MYC’s RNA-binding driven phase transition, may enable modulation of oncogenic transcriptional programs and immune evasion mechanisms.

Indirect Targeting Approaches

In addition to directly targeting the MYC protein, several strategies have been developed to inhibit proteins controlling MYC transcription, translation, and protein stability. Among these, synthetic lethality approaches have emerged as a particularly promising strategy for targeting “undruggable” proteins such as MYC. By identifying genes or pathways that become essential only in the context of MYC activation, these approaches reveal vulnerabilities that can be exploited therapeutically to selectively impair MYC-addicted tumor cells.

Targeting MYC Transcription

G-quadruplex DNA

The P1 promoter of MYC contains an upstream nuclease hypersensitivity element III ₁ (NHE III ₁) region, which accounts for 80–90% of MYC’s transcriptional activation. Due to its G-rich nature, this region can adopt a DNA secondary structure known as a G-quadruplex (G4), which impedes RNA polymerase progression and thereby suppresses MYC transcription [121, 122]. Consequently, small molecules and peptides that stabilize the MYC G4 structures have emerged as a potential alternative strategy for MYC-driven cancers.

The first MYC G4 binding drug to enter clinical trials was the fluoroquinolone quarfloxin (CX-3543), which progressed to phase II. However, although initially selected for MYC G4 binding, it primarily disrupted nucleolin-rDNA G4 complexes and was discontinued due to pharmacokinetic limitations and poor clinical efficacy [123]. Other prominent classes include perylene diimides, such as PIPER, which strongly induce MYC G4 formation; cationic porphyrins, particularly TMPyP4 and its more selective derivative Se2SAP; and quindoline derivatives, including SYUIQ-05, which exhibit strong MYC selectivity by binding G4 loop regions. However, despite demonstrating MYC G4 stabilization and antiproliferative activity, these compounds show limited target selectivity [124, 125]. More recently developed ligands, including D089, DHX36-derived peptides, repurposed drugs identified through ligand-based virtual screening, and several synthetic derivatives (EP12, m-Se3, carbohydrate-modified imidazoles, and 7-aza-8,9-methylene-dioxyindenoisoquinolines), as well as MYCN-selective binders such as MY-8, have demonstrated MYC/MYCN suppression in vitro and in vivo [126–131]. However, lack of specificity remains a major challenge for MYC G4 stabilizers, as most ligands bind broadly to G4 structures throughout the genome. This limitation has fueled the development of more selective approaches, such as DNA interference (DNAi) agents, including DNAi-5T and multisite binders designed to uniquely recognize MYC G4 structures [132]. Although some agents entered early clinical evaluation, no MYC G4 stabilizer has yet advanced successfully in clinical translation, due to persisting limitations in selectivity and stability.

BET Inhibitors

One of the most widely employed approaches to suppress MYC transcription involves inhibition of bromodomain and extra-terminal domain (BET) proteins. These epigenetic readers bind to acetylated lysine residues on histones and activate the transcription of multiple oncogenes, including MYC, as well as B-cell lymphoma 2 (BCL2) , CDK6, CCND1, and CCNA1 [133]. BET inhibitors (BETis) displace BET proteins such as BRD2 and 4 from chromatin, leading to super-enhancer collapse, promoter-proximal pausing of RNA polymerase II, and reduced transcriptional elongation, which results in widespread oncogene suppression. Notably, BETis do not completely shut down global gene expression, but rather selectively suppress transcriptional programs that cancer cells are unusually addicted to, driving their growth. Since MYC expression is driven by BET-dependent super enhancers in many cancer types and is highly dependent on BRD4, BETis demonstrate a strong impact on MYC oncogenic expression [134, 135]. Moreover, the rapid turnover of MYC mRNA and protein (approximately 20 min) renders MYC levels highly responsive to disruption of BET-mediated transcriptional regulation [136]. Thus, BET inhibition provides an indirect yet highly effective approach for cancers dependent on sustained MYC activity. Further, BETis indirectly reactivate tumor suppressor gene expression programs involved in apoptosis, senescence, and differentiation [134, 135]. Thus, the profound reshaping of global gene expression output underscores the antitumor effects mediated by BETis.

JQ1 and I-BET762 were the first BETis developed, providing powerful tools for investigating the function of BET proteins in cancer [137, 138]. JQ1 binds to the BD1 and BD2 bromodomains of BRD4, displacing the protein from the chromatin. This first-generation BETis showed anticancer properties in preclinical models of acute myeloid leukemia (AML) [139], breast cancer [140], lung cancer [141], and medulloblastoma (MB) [142]. However, its clinical potential has been limited by poor oral bioavailability and unfavorable pharmacokinetics [143]. In contrast, I-BET762 targets multiple BET family members (BRD2-4), exhibits improved oral bioavailability, and shows robust efficacy in preclinical models of MM [144], NB [145], and pancreatic cancer [146].

Subsequent BETis were designed to address the problems related to the bioavailability and pharmacokinetics of early compounds. For example, OTX-015, a pan-BETi structurally related to JQ1, presents improved pharmacokinetic properties and antitumor activity in preclinical models of hematological malignancies, including AML and acute lymphoblastic leukemia (ALL) [147], as well as solid tumors such as NB [148] and mesothelioma [149].

Next-generation BETis have been designed to enhance potency, selectivity, and tolerability. These include improved pan-BETis such as ABBV-075 (Mivebresib), MS417, MS645, and AZD5153, which achieve stronger BET targeting at lower concentrations and demonstrate improved preclinical efficacy compared with earlier agents [150–152]. In parallel, bromodomain-selective inhibitors, such as ABBV-744, GSK046, and ND-BET, preferentially target BD2, resulting in reduced systemic toxicity while maintaining transcriptional repression of oncogenic programs [153]. Additional innovative approaches include BET-targeting PROTAC degraders such as ARV-825 and dBET1 [154, 155], dual function molecules that combine BET inhibition with HDAC or Phosphoinositide 3-kinase (PI3K) blockade [156, 157], and covalent BETis such as ZEN-3694 and BI-894999 [158, 159]. Together, these next-generation BETis aim to improve selectivity, pharmacological properties, and therapeutic efficacy, representing more refined alternatives compared with the first-generation compounds. Promising preclinical results with BETis generated high expectations for their clinical translation, particularly in MYC-driven cancers. OTX-015 was the first one evaluated in clinical trials, with results indicating partial and complete responses in a minority of patients with diffuse large B-cell lymphoma and AML. However, responses were limited in MM as well as in most solid tumors treated [160].

In contrast, ABBV-075 evaluated in phase I studies in patients with advanced solid tumors and AML demonstrated a clinically manageable toxicity profile and evidence of stable disease or therapeutic response, particularly when combined with venetoclax in hematological malignancies [161]. However, response to treatment in solid tumors remained uncommon. Across clinical studies, dose-limiting toxicities, including thrombocytopenia, anemia, neutropenia, gastrointestinal events, and fatigue, have been commonly reported, reflecting the essential role of BET proteins in normal cellular homeostasis. This in turn highlights that although BETis hold therapeutic promise, their clinical efficacy remains limited, underscoring further research to better understand their mechanisms of action, optimize therapeutic strategies, and improve their impact on MYC-driven cancers.

CDK7 and CDK9 Inhibition

Another indirect approach to suppressing MYC transcription involves targeting CDK7 and CDK9, which play, which play key roles in transcription initiation and elongation. CDK7 functions as the catalytic subunit of the transcription factor IIH complex (TFIIH), regulating the assembly of the transcription initiation complex and RNA polymerase II promoter escape, whereas CDK9 is a component of the Positive transcription elongation factor b (P-TEFb); both regulate transcriptional elongation through phosphorylation of RNA polymerase II [162]. Since many cancer types depend on very high transcriptional output, inhibition of these kinases results in RNA polymerase stalling and rapid depletion in total RNA synthesis, with particularly prominent effects on oncogenic programs mediated by super-enhancers, such as those mediated by MYC and myleoid cell leukemia 1 (MCL-1). Notably, these CDKs are recruited to the MYC promoter, and CDK9 can additionally phosphorylate the MYC protein at serine 62 (S62), thereby stabilizing MYC and protecting it from degradation [163].

CDK7 inhibition using THZ1 has shown potent antitumor effects in preclinical models of triple-negative breast cancer (TNBC) [164], SCLC [165], and MYCN-driven NB [166]. Although THZ1 effectively suppresses MYC transcription, it lacks high selectivity as it also inhibits related kinases such as CDK12 and CDK13, thereby contributing to off-target effects [167, 168]. These limitations have fueled efforts to develop more selective CDK7 inhibitors, including ICEC0942, SY-1365, SY-5609, and LY340515, which have progressed to phase I/II clinical trials [169]. Furthermore, combination strategies, particularly with BET or CDK9 inhibitors, are being explored to enhance MYC transcriptional suppression and improve the therapeutic efficacy of CDK7 inhibition [170, 171].

Several CDK9 inhibitors, including AZD4573, KB-0742, and Fadraciclib (CYC065), are currently under clinical development, primarily for hematologic malignancies as well as solid tumors [172]. However, their clinical success has been limited due to significant toxicity arising from off- and on-target effects, together with modest clinical responses [173]. Moreover, prolonged CDK9 inhibition can paradoxically induce an increase in MYC expression, representing a potential resistance mechanism. This effect is believed to involve activation of otherwise inactive CDK9 via BRD4, which facilitates CDK9 recruitment to the MYC promoter [174, 175]. To address these challenges, targeted CDK9 PROTAC degraders, such as dCDK9-202 and KI-CDK9d-32, have demonstrated durable suppression of MYC transcription in preclinical models [176, 177].

Targeting MYC Translation

mTORC1 and eIF4F Inhibitors

Another indirect strategy for MYC inhibition involves exploiting the dependence of MYC mRNA on cap-dependent translation. The highly structured 5′ untranslated region (5’ UTR) of MYC mRNA requires the efficient assembly of the eukaryotic initiation factor 4F (eIF4F) complex, in which eIF4E binds the 5’ mRNA cap and associates with eIF4G to initiate translation. This process is promoted by mechanistic target of rapamycin complex 1 (mTORC1)-mediated phosphorylation of eukaryotic initiation factor 4E-binding protein 1 (4EBP1), which in turn releases eIF4E and facilitates eIF4F complex formation. Inhibitors that disrupt mTORC1 activity, eIF4F assembly, or eIF4A helicase function can therefore reduce MYC protein synthesis [178, 179]. Several mTORC1 inhibitors, such as rapamycin and its improved derivatives temsirolimus and everolimus, have been shown to decrease MYC expression and are used clinically for the treatment of multiple cancers, particularly renal cell carcinoma (RCC) [180].

Silvestrol and rocaglamide A, which target the eIF4A helicase component of the eIF4F complex, impair MYC translation and reduce proliferation in MYC-amplified group (GRP) 3 MB and erythroleukemia models [181]. Ribavirin inhibits eIF4E, the cap-binding subunit of the eIF4F translation initiation complex, and has shown modest clinical activity in early trials in eIF4E/MYC-driven tumors such as AML [182]. SBI-756 inhibits eI4F-dependent translation and sensitizes cancer cells to therapy. In combination with venetoclax, it enhances apoptosis in B-cell lymphomas [183] and suppresses tumor progression in pancreatic cancer, showing synergy with chemotherapy and anti-PD-1/PD-L1 checkpoint inhibitors [184].

RNA Polymerase I Inhibitors

MYC drives ribosomal biogenesis by upregulating the expression of genes involved in ribosomal RNA (rRNA) synthesis and ribosomal protein production. This enhances cellular capacity for ribosome assembly and supports the high rates of protein synthesis required for malignant growth. Elevated RNA polymerase I (RNA Pol I)-mediated transcription of rDNA is a key feature of MYC-driven tumors, positioning this enzyme as a potential therapeutic target [185]. Small-molecule RNA Pol I inhibitors such as CX5461 selectively suppress rRNA transcription, induce nucleolar stress, and trigger apoptosis. Importantly, these agents reduce MYC expression and proliferation in preclinical models of lymphoma, myeloma, and NB, providing proof-of-concept that disrupting ribosome biogenesis can selectively impair the growth of MYC-dependent cancers [186].

Targeting MYC Protein Stability

The MYC protein is highly unstable and is tightly regulated through post-transcriptional phosphorylation and ubiquitination. Phosphorylation occurs at two key residues located within MBI in the MYC amino-terminal domain, serine 62 (S62) and threonine 58 (T58), which have been shown to modulate MYC’s oncogenic capacity [187]. Phosphorylation of S62 by Extracellular signal receptor kinase (ERK), CDK2, and CDK5 stabilizes the MYC protein [188–190]. This modification is a prerequisite for subsequent phosphorylation at T58 by Glycogen synthase kinase 3β (GSK3β), which targets MYC for proteasomal degradation [191]. However, following the phosphorylation at T58, MYC is dephosphorylated at S62 by the protein phosphatase 2A (PP2A), a step necessary for recognition by the F-box and WD repeat domain-containing 7 (FBW7), a ubiquitin ligase complex, leading to MYC ubiquitination and proteasomal degradation [192, 193].

PIN1 Inhibitors

Peptidyl-prolyl isomerase NIMA-interacting-1 (PIN1) is a member of the peptidylprolyl cis/trans isomerase (PPIase) family. Following phosphorylation of MYC at S62, PIN1 regulates its stability by catalyzing isomerization of proline 63 (P63), generating structurally distinct MYC conformations. This isomerization also impacts the timing of MYC binding to DNA, its transcriptional activity, and subnuclear localization [194]. All-trans retinoic acid (ATRA) selectively inhibits PIN1 by direct binding to its active site, resulting in reduced tumor growth in MYC-driven leukemia, liver, and breast tumors [195]. Additionally, the covalent PIN1 inhibitor, sulfopin, has been shown to reduce tumor progression in animal models of PDAC and NB [196].

PP2A Activators

As PP2A regulates MYC dephosphorylation, a step necessary for its proteasomal degradation, pharmacologic activators of PP2A have been explored as indirect MYC inhibitors [197]. Fingolimod (FTY720) restores PP2A function, showing anticancer activity in hematological tumors [198, 199], as well as in glioblastoma (GBM) [200]. Similarly, the small molecule DT-061 activates and stabilizes PP2A, promoting sustained suppression of oncogenic targets, particularly MYC, in melanoma. Moreover, combining DT-061 with the MEK inhibitor AZD6244 showed synergistic inhibition of phosphorylated Ak strain transforming (p-AKT) protein and MYC signaling, resulting in tumor regression in preclinical models of KRAS-driven lung cancer [201].

USP7 Inhibitors

Ubiquitin-specific protease 7 (USP7) contributes to MYC signaling by indirectly stabilizing the MYC co-activator TRRAP, thereby enhancing its transcriptional activity, and by directly deubiquitinating and stabilizing MYCN, promoting oncogenic signaling. Several USP7 inhibitors have demonstrated promising effects in preclinical studies, including the non-covalent inhibitor FT671 in MM [202] and the highly potent USP7-797 in NB [203], as well as P02277 in models of NB [204] and HCC [205].

PLK1 Inhibitors

Polo-like kinase-1 (PLK1) regulates MYC stability by phosphorylating FBW7, which leads to its ubiquitination and subsequent proteasomal degradation, while MYCN can directly increase PLK1 transcription, forming a positive PLK1-MYCN feedback loop [206]. Several PLK1 inhibitors, including BI2536 (NCT02211872), volasertib (BI6727, NCT00824408), onvansertib (NCT05593328), and the multi-kinase inhibitor rigosertib (NCT01538537), are under clinical evaluation for solid tumors and AML. However, these agents have shown little benefit compared with standard chemotherapy, and thus, further studies are needed to improve the specificity and overcome resistance [207].

Synthetic Lethality Approach to Combat MYC-Driven Tumors

Synthetic lethality is a promising therapeutic strategy that exploits vulnerabilities created by MYC-driven oncogenic stress, including altered metabolism, replication stress, and dependence on protein homeostasis and transcriptional regulators. By selectively targeting these MYC-dependent pathways, synthetic lethality enables preferential killing of tumor cells while sparing normal tissues, providing an attractive alternative to direct MYC inhibition. Despite its potential, translating synthetic lethality into the clinic remains challenging due to cancer heterogeneity and compensatory mechanisms. However, several strategies, such as CDKis or BETis as well as targeting G1 to S phase transition GSPT1, have shown promising preclinical and early clinical results in exploiting MYC synthetic lethality.

BET Bromodomain 4 and Cyclin-Dependent Kinases

Targeting components of the MYC transcriptional machinery, such as BRD4 and CDK7/9, have been shown to induce synthetic lethality in cancer. While inhibition of BRD4 or transcriptional CDKs can also suppress MYC-driven programs, single-agent approaches are often limited by compensatory mechanisms, while combination strategies enhance efficacy. The simultaneous targeting of CDK9 and BRD4 prevents MYC reactivation that can occur with CDK9 inhibition alone, resulting in more durable suppression of MYC transcription and enhanced antitumor efficacy [174]. Similarly, dual inhibition of CDK7 and BRD4 more efficiently disrupts transcriptional initiation and elongation at MYC regulatory regions than either approach alone, leading to stronger and more sustained inhibition of MYC output [170, 208]. Overall, combination strategies more effectively impact MYC-driven transcriptional programs, enhance antitumor efficacy, and reduce adaptive resistance in tumors with oncogenic MYC activation.

CDK2 has emerged as a promising synthetic-lethality target in MYC-dependent tumors, including NBs with high MYCN expression [209], and in MYC/BCL-XL-driven mouse models of AML [210]. CDK2 inhibition has been shown to dampen MYC-signaling, induce combinations of cell death and neuronal differentiation in NB cells [209, 211, 212], and trigger cellular senescence in AML cells [210]. Notably, concurrent inhibition of CDK2 (milciclib) and MYC/MYCN (JQ1) produces synergistic antitumor effects in vitro [211]. Similarly, dual targeting of CDK9/2 using CYC065 (fadraciclib) selectively killed NB cells and induced neuronal differentiation [211, 214, 215]. The potential of CDK inhibition as a differentiation therapy in NB is further supported by recent findings with CDK4/6 inhibitors. Agents such as palbociclib and abemaciclib induce neuronal differentiation either alone or in combination with standard of care maintenance therapy, such as isotretinoin [215, 216]. Palbociclib (NCT01740427) [217] and abemaciclib (NCT03155997) [213], in combination with endocrine therapy, are US Food and Drug Administration (FDA)-approved as first-line therapy of hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer at high risk of recurrance. The clinical success has prompted the evaluation of these CDK4/6 inhibitors in multiple types of cancers, including MYC/MYCN-dependent tumors such as NB, MB, glioma, and lymphoma (NCT03526250, NCT03155620, NCT02644460, NCT04238819). Considering these developments and the negative impact of CDK inhibition on MYC/MYCN signaling, it would be interesting to explore the combination of CDKis with the clinically relevant MYC inhibitor OMO-103 in patients with MYC/MYCN-driven tumors. Such strategies could potentially enhance antitumor efficacy while promoting differentiation and limiting tumor progression.

GSPT1

The translation termination factor GSPT1 is essential for the proliferation of tumors with elevated MYC activity. Due to oncogenic signaling, these cancers are highly dependent on sustained protein synthesis. Targeted degradation of GSPT1 disrupts global translation and suppresses MYC transcriptional output, revealing a promising synthetic–lethal vulnerability [218]. MRT-2359, a GSPT1 molecular degrader, is currently in a phase I/II trial (NCT05546268) for patients with selected solid tumors characterized by elevated MYC levels. Early results confirm on-target activity and suggest promising clinical activity, particularly in tumors with high MYCL and MYCN expression.

Aurora Kinase A

In MYCN-amplified NB, MYCN cooperates with AURKA to suppress transcription-replication conflicts and maintain genomic stability. MYCN forms a complex with AURKA on chromatin, promoting histone H3 phosphorylation and incorporation while preventing R-loop accumulation. AURKA inhibition induces replication stress and activates ataxia telangiectasia and rad3-related (ATR) signaling. The combined inhibition of AURKA and ATR induces apoptosis and permanent tumor regression in mouse models of NB, supporting the concomitant targeting of AURKA and ATR as a promising synthetic lethal strategy in MYCN-amplified NB [219].

Targeting MYC Downstream Effectors/Dependencies

Although MYC remains one of the most therapeutically challenging oncogenic drivers in human cancers, its downstream effects and acquired dependencies reveal actionable vulnerabilities. Targeting these effector processes, including metabolism, cell cycle regulation, transcription, and ribosome biogenesis, exploits the oncogenic stress associated with MYC-dependent tumors and provides an alternative to direct inhibition. Here, we review recent advances highlighting epigenetic modifiers and metabolic pathways as potential therapeutic strategies to suppress the MYC oncoprotein family’s tumorigenic capacity.

Targeting Epigenetic Modifiers

Aberrant epigenetic mechanisms are recognized as a hallmark of cancer, influencing all stages of tumorigenesis, including tumor initiation, progression, metastasis, and response to therapy [220]. Deregulated epigenetic processes promote cellular plasticity and intratumoral heterogeneity, thereby conferring survival advantages that enable cancer cells to rapidly adapt to adverse conditions such as hypoxia, nutrient limitation, immune recognition, and anticancer therapies [221]. Unlike genetic mutations, epigenetic modifications, including DNA methylation, histone modifications, and chromatin remodeling, are dynamic and potentially reversible, making them attractive therapeutic targets as exemplified by the FDA approval of inhibitors against DNA methyltransferases, HDACs, and histone methyltransferases [222, 223]. Given the broad engagement of MYC family transcription factors with epigenetic regulators of both gene activation and repression, targeting downstream epigenetic mechanisms emerges as a compelling therapeutic strategy for MYC/MYCN-driven cancers. In general, tumors are addicted to certain gene expression programs encompassing high expression of oncogenic pathways that fuel tumor growth in combination with repressed gene signatures dampening antitumor mechanisms [224]. Epigenetic inhibitors rewire global gene expression in cancer cells by altering chromatin accessibility, enhancer function, and recruitment of transcriptional machinery factors. These effects are selective, as oncogenes driven by super-enhancers such as MYC and BCL2, as well as tumor-suppressing programs including cell cycle checkpoints, cell differentiation, and immune activation, are sensitive to epigenetic intervention [225]. Thus, the antitumor effects of epigenetic inhibitors rely largely on their ability to disrupt the balance between oncogenic and tumor suppressor gene expression circuits [226]. In this review, we briefly discuss the impact of epigenetic inhibitors on global gene expression and focus on their effect on MYC-driven effects.

Targeting the DNA Methyltransferases

DNA methylation is an epigenetic modification involving the addition of methyl groups to cytosine residues, typically within CpG sites, thereby regulating gene expression without altering the underlying DNA sequence [227, 228]. It is catalyzed by DNA methyltransferases (DNMTs), where DNMT1 functions as a maintenance methylase that preserves established methylation patterns during DNA replication, while DNMT3A and DNMT3B mediate the establishment of de novo methylation profiles [228, 229]. Conversely, DNA methylation is actively removed by members of the ten-eleven translocation (TET) enzyme family, which oxidizes methyl cytosine and initiates the DNA demethylation process [228, 230]. Mutations or dysregulated expression of these enzymes commonly result in aberrant DNA methylation patterns in cancer cells, where promoter hypermethylation silences tumor suppressor genes, while genome-wide hypomethylation mediates genomic instability and oncogene activation [227, 228]. Aberrant DNA methylation profiles contribute to cancer initiation, progression, metastasis, and therapy resistance [228]. Consequently, targeting the DNA methylation machinery has significant clinical potential, with DNMT inhibitors already approved for the treatment of hematologic malignancies and being explored in combination with immunotherapy and targeted therapies to improve outcomes in solid tumors [231]. The impact of targeting DNA methylation in cancer cells has been extensively studied, and the general consensus is that modulation of DNA methylation profiles enhances transcriptional diversity, leading to reduced activity of oncogenic transcriptional programs such as those driven by MYC, reactivation of silenced tumor suppressor genes involved in cell differentiation and cell death, as well as immunomodulation [232].

MYC physically interacts with DNMT3A, a requirement for MYC-mediated repression of CDKN1A in cooperation with MIZ-1 in rat fibroblasts [233]. Notably, treatment with the DNA methyltransferase inhibitor 5-azacytidine (5-AZA) induced expression of CDKN1A in MYC-proficient but not in MYC-deficient fibroblasts [233], suggesting that MYC status may serve as a predictive response marker to DNMT inhibition. In MYC-dependent T cell acute lymphocytic leukemia (T-ALL) and BL models, MYC drives overexpression of DNMT1 and DNMT3B, providing evidence for its direct deregulation of DNA methylation in a genome-wide fashion, facilitating tumor maintenance [234]. In MM, high expression of DNMT3B correlates with disease progression, high-risk, and relapsed cases, irrespective of treatment type [235]. Targeting DNMT3B using either genetic depletion or pharmacological inhibition by nanaomycin A impaired MM cell growth, survival, and clonogenicity [235]. This effect has been attributed to DNMT3B depletion, which negatively impacts MYC stability and reduces MYC levels in myeloma cells [235]. In BL, high MYC expression sensitizes p53-deficient cells to Decitabine [5-aza-2′-deoxycytidine (5-aza-dC)], leading to DNA damage-induced cell death [236], whereas in NB, promoter hypermethylation of a set of genes including Tripartite motif 63 (TRIM63), V-set and transmembrane domain-containing protein 2-like (VSTM2L), Glycoprotein non-metastatic melanoma protein B (GPNMB), and Tissue inhibitor of metalloproteinases 3 (TIMP3) has been associated with resistance to enhancer of zeste homolog 2 (EZH2) inhibition [237]. Combined targeting of EZH2 (EPZ-6438) and DNA methylation (5-aza-dC) restored the expression of methylation-repressed genes, sensitized EZH2 inhibitor-resistant NB cells to EZH2 inhibition, and reduced cell proliferation [237]. Importantly, combination treatment induced a robust differentiation phenotype, associated with MYCN protein destabilization in MYCN-amplified NB cells and suppression of MYC expression at both RNA and protein levels in cells lacking MYCN-amplification [237]. The recent development of OMO-103, the first direct MYC inhibitor with clinical relevance [37], makes its combination with DNMTis an intriguing therapeutic approach for MYC/MYCN-driven tumors that warrant further investigation. Additionally, targeting MYC/MYCN interactions with DNMTs using small molecules or peptides could further expand therapeutic options.

MYC regulates the expression of TET1 and TET2 in T-ALL to maintain 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) patterns and preserve tumor cell-specific gene expression profiles [238]. MYC drives TET1, but represses TET2 expression in T-ALL, whereas MYC inactivation reverses this pattern, decreasing TET1 and increasing TET2 levels [238]. Functional studies have shown that TET1 knockdown or TET2 overexpression reduces T-ALL cell proliferation, induces genome-wide changes in 5mC/5hmC, and dampens pathways linked to ribosome biogenesis and protein synthesis, key hallmark features of MYC activity [238]. Supporting these findings, TET1 knockdown or pharmacological inhibition with auranofin suppressed T-ALL growth and progression in vitro and in vivo, downregulating 5hmC levels and reducing MYC mRNA and protein in a TET1-dependent manner [239]. In MYCN-amplified NB cells, TET1 expression is upregulated under hypoxic conditions, coinciding with increased global 5hmC across introns, promoters, and regulatory elements. This epigenetic remodeling creates a transcriptionally permissive state for genes involved in dopamine receptor signaling [240]. MYCN has been shown to directly control TET1 expression during normoxia and to cooperate with hypoxia inducible factor 1 alpha (HIF-1α) to enhance TET1 expression under hypoxic conditions. Notably, hypoxic MYCN-amplified NB cells have increased cell migration capacity mediated by a certain set of genes that gain 5hmC [240]. Auranofin-mediated inhibition of thioredoxin reductase induces ferroptosis, and its combination with standard chemotherapy led to improved survival in a chemo-resistant NB patient-derived xenograft (PDX) [241]. It remains to be determined whether auranofin sensitizes chemo-resistant NB to standard chemotherapy in part due to the genome-wide reprogramming of a 5mC/5hmC profile. The development of TET inhibitors is ongoing, with reported antitumor activity in preclinical cancer models. However, no specific TET inhibitor has yet advanced to clinical trials. Current inhibitors, including Bobcat339, TETi76, and C35, lack isoform specificity, i.e., targeting TET1/2/3, and their antitumor activity in MYC/MYCN-driven tumors remains to be established.

Targeting Histone Acetylation

Histone acetylation, a reversible epigenetic mark, promotes an open chromatin configuration favoring transcriptionally active regions. It is dynamically regulated by histone acetyltransferases (HATs), which catalyze the addition of acetyl groups, and HDACs, which erase them [242, 243]. Further, histone acetylation functions as a signaling platform read by BET proteins, which recruit transcriptional co-activators, chromatin remodelers, and the basal transcription machinery [242, 243]. Thus, the orchestrated balance of HATs, HDACs, and BET proteins shapes gene expression in a context-dependent manner [242, 243]. Aberrant expression and activity of these three classes of proteins lead to abnormal histone acetylation profiles that promote tumor development across a wide range of cancers, which is highlighted by the FDA approval of HDAC inhibitors for the treatment of several human malignancies [244, 245]. HAT and HDAC inhibitors demonstrate pleiotropic antitumor effects via modulation of histone as well as non-histone protein acetylation. By impacting histone acetylation profiles, HAT and HDAC inhibitors reshape the epigenomic landscape and chromatin accessibility in cancer cells, which is associated with suppressed expression of oncogenes, including MYC, CCND1, and super-enhancer-driven transcriptional networks, as well as reactivation of silenced tumor suppressor genes such as CDKN1A/p21 and TP53 [246]. Acetylation also regulates the activity and stability of other essential transcription factors contributing to tumorigenesis, including E2F, MYC, HIF1α, and nuclear factor kappa B (NF-κB) [247]. Thus, targeting histone acetylation by HAT and HDAC inhibitors can rebalance oncogenic and tumor suppressor gene expression programs, particularly in tumors that are addicted to elevated levels of transcription, as in MYC/MYCN-driven tumors.

The MYC proteins drive oncogenic gene expression programs through interactions with the TRRAP coactivator, recruiting HATs such as General control non-depressible 5 (GCN5), Tat-interactive protein 60 (TIP60), and p300/Cyclic AMP response element-binding protein (CBP), thereby enhancing transcriptional activation of target genes [248–250]. Genome-wide studies have shown that overexpressed MYC/MYCN proteins accumulate at super-enhancers, increase histone acetylation at these regions, promoting strong gene expression programs related to oncogenesis, establishing enhancer hijacking in cancer cells with high MYC levels [251–253]. Conversely, MYC family proteins interact with MIZ-1 and the SIN3A/SIN3B co-repressor complex to recruit HDACs, including HDAC1 and HDAC2, thereby silencing specific target genes [254, 255]. Furthermore, MYC via MBIII directly interacts with and recruits HDAC3 to silence gene expression [256, 257]. Thus, MYC proteins modulate histone acetylation dynamics to sustain deregulated transcription in cancer, making this a therapeutic target to counteract MYC oncogenic functions.

Targeting HATs and HDACs has demonstrated potent antitumor activity in preclinical models of MYC/MYCN-driven tumors. For example, the class I HDAC inhibitor entinostat (MS-275/SNDX-275), which preferentially targets HDAC1 and HDAC3, inhibits luminal breast cancer cell growth in vitro and in vivo, accompanied by downregulation of MYC expression and its target genes [258]. Similar effects were observed in MYC-amplified MB [259, 260], rhabdomyosarcoma [261], as well as in NB [262], where entinostat impairs MYC DNA-binding. Another class I selective HDAC inhibitor, CI-994 (tacedinaline), shows MYC-dependent antitumor activity in MB models both in vitro and in vivo [263]. The pan-HDAC inhibitor vorinostat induces apoptosis and reduces MYC expression in the Eμ-myc lymphoma mouse model [264, 265]. In MM, HDAC inhibitors exhibit promising antitumor efficacy, leading to FDA approval of panobinostat in combination with proteasome inhibitors. In parallel, vorinostat (NCT00111813, NCT00773747, NCT00839956) and ricolinostat (NCT01997840, NCT01583283, NCT01323751) are currently under clinical evaluation in combination with proteasome inhibitors or immunomodulatory agents in refractory disease.

Inhibitors targeting HATs such as p300/CBP demonstrate antitumor activity in multiple cancers. In PCa, A-485 inhibits the androgen receptor transcriptional program, suppresses MYC expression, and reduces tumor growth in castration-resistant xenograft models [266]. These findings are reinforced by CCS1477, a p300/CBP bromodomain inhibitor, which exerts its antitumor effects in part by modulating the TME, enhancing tumor-infiltrating lymphocytes, and improving the efficacy of immune checkpoint blockade therapy in PCa and melanoma models [267, 268]. CCS1477 further demonstrated greater antitumor activity and more potent suppression of the MYC pathway compared with A-458 in GRP 3 MB cells [269]. CCS1477 is currently in phase I/II trials under the clinical name inobrodib in hematological malignancies (NCT07096778, NCT04068597). Inhibition of the HATs lysine acetyltransferase 6A and 6B (KAT6A/6B) using small molecules such as WM-8014 and WM-1119 induces senescence and suppresses tumor growth in the Eμ-myc lymphoma mouse model [270]. In estrogen receptor-positive breast cancer cells overexpressing KAT6A, CTX648 reduces RNA Pol II binding and downregulates genes involved in estrogen signaling, cell cycle regulation, MYC, and stem cell pathways, correlating with reduced tumor cell proliferation [271]. Similarly, in non-SCLC (NSCLC), genetic and pharmacological inhibition of the GCN5 HAT decreases MYC expression, cell proliferation, and increases cell death [272]. Collectively, these findings indicate that targeting HATs and HDACs disrupts chromatin acetylation dynamics, suppressing MYC/MYCN transcriptional output and oncogenic signaling, thereby revealing the histone acetylation machinery as a therapeutically exploitable vulnerability in MYC/MYCN-driven cancers.

Targeting the Enhancer of Zeste Homolog 2 (EZH2)

The enhancer of zeste homolog 2 (EZH2) is the enzymatic subunit of the polycomb repressive complex 2 (PRC2), catalyzing tri-methylation of histone 3 at lysine 27 (H3K27me3), a repressive histone mark that regulates gene expression programs involved in stem cell self-renewal, cell cycle checkpoints, and differentiation [273, 274]. Aberrant EZH2 activity and dysregulated H3K27me3 patterns can disrupt normal development and tissue homeostasis, contributing to cellular transformation and tumorigenesis [273, 274]. Numerous studies have implicated EZH2 overexpression in a broad spectrum of hematological and solid tumors in both adults and children. The identification of gain-of-function EZH2 mutations in B-cell lymphoma has accelerated the development of small-molecule inhibitors that suppress EZH2 methyltransferase activity, demonstrating anticancer activity in tumors with mutant or wild-type EZH2 [275, 276]. Like inhibitors targeting DNA methylation and histone acetylation, EZH2is reprogram the epigenetic landscape and transcriptional readout in cancer cells. EZH2 inhibition derepresses antiproliferative and lineage differentiation transcriptional programs, as well as enhances tumor immunogenicity by inducing interferon-response genes, the antigen-presentation machinery, chemokines, and endogenous retroviral elements [277, 278]. Further, EZH2is directly or indirectly disrupt chromatin states that support stemness features, EMT transition, metastatic spread, and oncogenic signaling networks driven by MYC, Wingless-related integration site (WNT)/β-catenin, PI3K/AKT, or E2F [279]. Such profound antitumor effects in preclinical cancer models have led to FDA approval of tazemetostat (Tazverik), the first-in-class oral EZH2 inhibitor, for patients with follicular lymphoma and epithelioid sarcoma [280, 281].

Notably, EZH2 is a MYC target gene, and several studies have shown that MYC and MYCN drive EZH2 expression in cancer cells [282–286]. Furthermore, EZH2 and MYC/MYCN physically interact in a range of tumors, including B-cell lymphoma [287, 288], MM [289], NB [290, 291], SCLC [291], peripheral T-cell lymphoma (PTCL) [284], and PCa [292]. These interactions are critical for MYC/MYCN transcriptional activity, enabling both activation and repression of target genes, and establishing a positive feedback loop whereby EZH2 silences miRNAs that negatively regulate MYC/MYCN and EZH2 expression [282, 287, 293–295]. Together, these findings highlight EZH2 as a cancer dependency in MYC/MYCN-driven tumors. Consistent with this, pharmacological or genetic targeting of EZH2 in human cancer cell lines and murine models decreases MYC/MYCN mRNA and protein levels, reduces their transcriptional activity, and downregulates target gene expression, producing significant antitumor effects [287, 291, 294, 296]. EZH2 inhibition has been shown to reduce MYC mRNA levels in MM [294], PCa [296], B-cell lymphoma [287], and GRP 3 MYC-amplified MB [297], through upregulation of MYC-targeting miRNAs. EZH2 also stabilizes MYC/MYCN protein levels in NB by protection from FBW7α-mediated degradation, a mechanism independent of its enzymatic activity [291]. In MYCN-driven PTCL, EZH2 functions as a positive regulator of MYCN transactivation independent of its histone methyltransferase activity [284]. Notably, EZH2, but not other PRC2 subunits, binds MYCN at active sites of transcription in a manner dependent on CDK1-mediated phosphorylation of EZH2 at threonine 487 (T487) [284]. Pharmacological inhibition of CDK1 using Ro-3306 reduces EZH2 phosphorylation, leading to degradation of both EZH2 and MYCN, and downregulates genes co-regulated by these factors [284]. In MM, EZH2 and MYC interact at active chromatin loci to stimulate MYC transcriptional activity. This activity is attenuated by the EZH2 degrader MS177, resulting in decreased MYC protein levels [289, 298].

The pleiotropic effects of EZH2 inhibition on MYC/MYCN, including decreased transcription, protein levels, stability, and downstream transcriptional output (Fig. 6), highlight both enzymatic inhibitors and EZH2 degraders as promising therapeutic approaches in MYC/MYCN-dependent tumors. Moreover, the robust functional crosstalk between EZH2 and MYC/MYCN in cancer, coupled with the availability of clinically relevant inhibitors targeting EZH2 (tazemetostat) and MYC (OMO-103), provides a strong rationale for evaluating their combination in tumors driven by deregulated MYC/MYCN expression. Further, EZH2 PROTACs via targeting both methyltransferase-dependent and independent gene regulatory functions represent an attractive strategy to treat EZH2-dependent tumors, including MYC/MYCN-driven cancers. In addition, several EZH2is including UNC1999, also targets EZH1, a related homolog of EZH2 which serves an alternative catalytic subunit of PRC2 and can compensate for EZH2 activity. Thus selective or dual EZH1/2 inhibition is an attractive approach to enhance the efficacy of existing therapies while providing a novel strategy for treating aggressive MYC/MYCN-dependent malignancies.

Fig. 6.

EZH2 enhances MYC/MYCN-driven oncogenic transcriptional programs. A EZH2 functions as part of the PRC2 complex and stimulates MYC/MYCN-mediated repression of tumor suppressor genes in a histone methyltransferase-dependent manner. B Phosphorylated EZH2 enhances MYC/MYCN gene transcription by protecting MYC/MYCN from proteasomal degradation, independently of PRC2 and enzymatic activity. Designed using Biorender.com.

Targeting Euchromatic Histone-Lysine N-Methyltransferase 2 (EHMT2)

The euchromatic histone-lysine N-methyltransferase 2 (EHMT2), also known as G9a, is a histone 3 lysine 9 (H3K9) methyltransferase that catalyzes mono- and dimethylation (H3K9me1 and H3K9me2) at promoter regions, leading to gene repression [299]. G9a has also been reported to monomethylate H3K27 (H3K27me1), serving as a template for EZH2-mediated H3K27 di- and trimethylation and subsequent gene repression [300, 301]. It plays key roles in normal development and tissue homeostasis [299], and its aberrant expression is frequently observed across multiple cancers such as breast cancer, melanoma, MM, lymphoma, PCa, and ovarian cancer [302–304]. In breast cancer, G9a interacts with MYC via MBII, required for MYC-mediated gene repression through H3K9me2 [305]. G9a depletion has been shown to alter the MYC chromatin-binding landscape, antagonize MYC-mediated gene suppression, and inhibit cell growth in a breast cancer xenograft model [305]. Importantly, pharmacological inhibition of G9a using UNC0642 demonstrated MYC-dependent antitumor activity [305]. In HCC, G9a expression positively correlates with MYC levels, and the co-expression of G9a and MYC is associated with poor prognosis [306]. Mechanistically, G9a interacts with MYC, stabilizing MYC protein levels, promoting MYC-dependent gene repression, and enhancing the invasive capacity of HCC cells [306]. Consistently, G9a inhibition demonstrates potent antitumor activity in MYC-high HCC models in vitro and in HCC PDX organoids in vivo, particularly when combined with the CDK9 inhibitor dinaciclib [306]. In TNBC, a tumor subtype characterized by high MYC activity [307, 308], G9a inhibition using UNC0638 suppresses EMT transition, reduces cancer stem cell properties, and impairs cellular migration and invasion in vitro [309]. Furthermore, G9a has been shown to cooperate with EZH2 to repress the tumor-suppressor genes SMAD familiy member 4 (SMAD4), thereby activating the ERK/MYC signaling pathway and promoting drug resistance in NSCLC [310]. Dual targeting of EZH2 and G9a using SU08 reduces MYC and phosphorylated ERK (p-ERK) levels and sensitizes drug-resistant NSCLC cell lines and PDX models to cisplatin, paclitaxel, and erlotinib [310].

In NB, G9a overexpression has been found in MYCN-amplified cell lines and primary tumors, and high G9a expression is associated with poor patient survival [311]. Its knockdown or pharmacological inhibition using UNC0638, UNC0642, or BIX-01294 in MYCN-amplified cell lines reactivated tumor suppressor genes, inhibited the expression of canonical-MYC activated target genes, and promoted cell death [311]. Moreover, MYCN has recently been shown to physically interact and cooperate with G9a and WDR5 to promote oncogenesis [29]. MYCN-G9a interaction is required for suppression of MYCN-target genes involved in neuronal differentiation, whereas the MYCN-WDR5 interaction drives the expression of canonical MYC target genes associated with ribosomal biogenesis, cell proliferation, and metabolic programs [29]. Thus, MYCN-G9a complexes are enriched at enhancer and promoter regions of MYC-repressed genes, while MYCN-WDR5 complexes are localized to promoters of MYC-activated genes [29]. These findings indicate that MYCN employs different chromatin modifiers and regulatory elements to exert its oncogenic functions. In line with this notion, combined treatment of WDR5 (OICR-9429) and G9a (UNC0642) inhibitors markedly reduced cell proliferation compared with single-agent treatment, suggesting that simultaneous inhibition of MYCN co-activators and co-repressors represents a promising therapeutic approach to target MYC/MYCN-driven cancers [29].

In MM, targeting G9a and its interacting protein G9a-like protein (GLP) blocks mTOR/4EBP1 signaling, reduces MYC mRNA and protein levels, induces autophagy-associated apoptosis, and enhances the efficacy of proteasome inhibitor-based therapies in murine and human cell lines [312]. Similarly, genetic or pharmacological inhibition of G9a in GBM cells reduces MYC protein levels and suppresses cell proliferation, cell migration, and invasion, but also induces autophagy [313]. Importantly, these effects were reversed upon MYC overexpression in G9a-deficient GBM cells, highlighting G9a as a promising candidate to inhibit MYC-driven oncogenic activity [313].

Autophagy is a conserved lysosome-dependent catabolic process that maintains cellular homeostasis by degrading damaged organelles, protein aggregates, and metabolic substrates [314]. In cancer, autophagy plays a context-dependent dual role, functioning as a tumor suppressor during early tumorigenesis while supporting tumor survival in established malignancies [315, 316]. The ability of G9a inhibition to induce autophagy in MYC-dependent tumors, such as MM [312] and GBM [313], suggests that modulation of autophagy may represent a potential anticancer approach. Combined targeting of G9a and MYC could therefore provide therapeutic benefit, warranting further investigation in preclinical cancer models.

Targeting BMI1 and Histone Ubiquitination

B lymphoma Mo-MLV insertion region 1 homolog (BMI1) is a core epigenetic regulator in the polycomb repressive complex 1 (PRC1), which stimulates RING1A/B ubiquitin ligases to catalyze mono-ubiquitination of histone H2A at lysine 119 (H2AK119ub1), an epigenetic mark associated with gene silencing and heterochromatin formation [317]. BMI1/PRC1 and the associated H2AK119ub repressive histone mark regulate chromatin accessibility genome-wide, maintaining oncogenic gene expression programs that support stemness, cell proliferation, and the DNA damage response, while silencing genes involved in senescence, apoptosis, and differentiation [318]. Thus, targeting BMI1/PRC1/H2AK119ub has been shown to rewire the global gene expression program in cancer cells by suppressing oncogenic processes, including the MYC pathway, and enhancing antitumor mechanisms. Bmi1 was initially identified as a factor that accelerates lymphomagenesis in B and T cells in the Eμ–myc transgenic mouse model [319, 320], which is believed to be mediated by repression of the INK4a/ARF tumor suppressor locus [321]. Since then, BMI1 deregulation has been reported in several cancer types, many of which are MYC/MYCN-dependent, such as MM [322], NB [323], GBM [324], and MB [325]. It promotes tumorigenesis by regulating several hallmarks of cancer, including tumor stemness, proliferation, invasion, metastasis, and therapy resistance [326]. In NB, MYC/MYCN [327, 328] and E2F-1 [329] drive BMI1 overexpression, which correlates with aggressive tumor phenotype. Moreover, BMI1 suppresses cell death through direct repression of FBW7, a Stem cell factor (SCF) E3 ubiquitin ligase involved in protein degradation, resulting in sustained cyclin E1 expression and enhanced cell proliferation [330].

In MB, BMI1 overexpression has been shown to enhance the proliferation of granule cell precursors by modulating gene expression within the sonic hedgehog (SHH) signaling pathway [331, 332]. Consistent with findings in the Eμ–myc transgenic mouse model, BMI1 promotes MB progression through direct regulation of cell cycle inhibitors, including INK4a/ARF and CDKNA1 [p21(Waf1/Cip1)] [332]. In group 4 MB models, BMI1 also promotes cell migration, invasion, and extracellular matrix (ECM) remodeling by suppressing bone morphogenetic proteins (BMP), which normally inhibit proliferation and enhance differentiation [333]. Moreover, in vivo studies have demonstrated that BMI1 supports MYCN-driven tumor initiation in embryonic tumors such as NB, MB, and ALL by suppressing p53-dependent responses in tumor precursor cells [334]. Mechanistically, BMI1 in complex with Really interesting new gene 1A/1B (RING1A/B) ubiquitin ligases promotes poly-ubiquitination of p53, leading to its degradation [334]. In MM, BMI1 supports cell growth via both tumor intrinsic [322] and extrinsic [335] mechanisms. Intrinsically, BMI1 enhances proliferation through direct repression of the pro-apoptotic BIM gene [322]. Extrinsically, BMI1 overexpression driven by the SHH-MYC axis in myeloma-associated macrophages promotes their pro-angiogenic function and chemoresistance [335].

BMI1 is highly expressed in CD133-positive human GBM cells, where it prevents apoptosis and inhibits differentiation into neuronal and astrocytic lineages [324]. In these cells, BMI1 represses tumor suppressor pathways that attempt to compensate for INK4A/ARF/p53 loss and PI3K/AKT hyperactivation [324], while also enhancing gene expression programs associated with stem cell-like properties [336]. In normal cells, activation or overexpression of the MYC family induces apoptosis through both p53-dependent and independent pathways [337–339]. Therefore, MYC/MYCN-driven overexpression of BMI1 in cancer precursor cells, early during tumorigenesis, as well as in established cancer cells, suppresses key safeguard mechanisms mediated by the INK4A/ARF/p53/p21[Waf1/Cip1] axis. This, in turn, enables MYC/MYCN to bypass oncogene-induced apoptosis, sustain cell proliferation, and drive tumor progression.

The development of small-molecule BMI1 inhibitors such as PTC-209 and PTC-028 has highlighted the therapeutic potential of targeting BMI1 in cancer, including MYC/MYCN-driven tumors. Treatment with PTC-02 resulted in complete ablation of GRP 3 MB self-renewal capacity in vitro, and significantly reduced tumor burden in both local and metastatic compartments in PDX models, leading to prolonged survival without signs of neurotoxicity [340]. Notably, PTC-028 selectively downregulated tumor-promoting pathways, including MYC signaling, oxidative phosphorylation, and glycolysis [340]. Furthermore, BMI1 inhibition using PTC-209 decreased MM cell viability, increased G1 cell cycle arrest, and promoted apoptosis [341, 342]. Notably, PTC-209 robustly reduced MYC expression in these cells [341] and demonstrated synergistic antitumor effects when combined with BET-bromodomain inhibition [342]. In MYCN-amplified NB cell lines, both PTC-028 and PTC-209 exhibited selective tumor suppressive activity in vitro and in vivo, triggering p53-dependent apoptosis and promoting cell cycle arrest, further supporting BMI1 as a promising therapeutic target in MYC/MYCN-driven cancers [343]. Recent studies have reported resistance to BMI1 inhibition with PTC-209 in head and neck squamous cell carcinoma (HNSCC), which has been attributed to increased MYC expression in tumor cells, causing the acquisition of a cancer stem cell phenotype [344]. In this context, genetic or pharmacological inhibition of MYC synergized with BMI1 targeting to eradicate HNSCC cancer stem cells and prevent tumor relapse [344]. Targeting BMI1 using PTC596 or A1016 has also demonstrated antitumor activity in vitro and in vivo models of human GBM [345]. However, PTC596, but not A1016, induced activation of an EMT molecular program in treated cells, which has been associated with tumor relapse in some mice bearing intracranial tumors, potentially through de-repression of PRC2-target genes [345]. Notably, PTC596 has been described as a potent microtubule polymerization inhibitor with anticancer activity either as a single agent or in combination with standard-of-care therapies in leiomyosarcoma, GBM [346], MM [347, 348], and PDAC [349]. This dual mechanism of action may explain potential off-target effects observed in GBM models [345]. In a phase I, open-label, multiple-ascending-dose clinical trial involving 31 patients with advanced solid tumors (NCT02404480), PTC596 has demonstrated acceptable tolerability, with mild-to-moderate adverse effects, and stable disease response was observed in seven patients [350]. On the basis of these findings, phase Ib clinical trials evaluating PTC596 have been initiated in children with newly diagnosed diffuse intrinsic pontine glioma and high-grade glioma (NCT03605550) [351], as well as in patients with advanced leiomyosarcoma (NCT03761095) [352]. Considering these studies, together with the observed suppressive effects of BMI1 inhibitors on MYC expression and signaling, evaluating combination strategies using BMI1 inhibitors (e.g., PTC596 or PTC-028) and OMO-103 in preclinical models of MYC/MYCN-driven tumors may provide a promising therapeutic strategy for these aggressive malignancies.

Targeting Histone Demethylases

Histone demethylases (KDMs) play central roles in cancer-associated oncogenic programs by altering chromatin states to favor transcriptional activation of proliferation-associated genes and repression of tumor suppressor pathways. Many oncogenic enhancers require specific chromatin states maintained by KDMs. In turn, KDM inhibition changes transcriptional circuits by disrupting super-enhancer-promoter interactions essential for driving oncogenic transcriptional programs, such as the ones mediated by MYC, as well as reactivating tumor suppressor genes and immune-related genes, including those involved in the interferon-response genes, the antigen-presentation machinery, and endogenous retroviral elements [353].

Lysine-specific demethylase 1/lysine demethylase 1 A (LSD1/KDM1A) catalyzes the demethylation of mono- and dimethylated lysine 4 or lysine 9 on histone H3 (H3K4me1/2 and H3K9me1/2), thereby functioning as either a transcriptional repressor or activator, respectively [354]. Notably, LSD1 mRNA expression levels have been shown to correlate with MYC expression in AML, GBM, stomach cancer, and PCa [355]. Furthermore, LSD1/KDM1A has been experimentally established as a MYC target gene in several human cancer cell lines [355]. Functionally, MYC interacts with LSD1/KDM1A at E-box elements, inducing a transient H3K4 demethylation that promotes assembly of the MYC-driven transcription initiation complex and subsequent activation of target genes in Rat1 cells expressing a 4-hydroxytamoxifen (4-OHT)-inducible MYC^ER construct [356].

In NB cells, MYCN physically interacts with LSD1/KDM1via MBIII to repress the expression of tumor suppressor genes, including CDKN1A/p21 and Clusterin (CLU) [357]. Combined inhibition of MYCN:MAX interactions and LSD1/KDM1 has demonstrated potent antitumor activity in vitro [357]. Moreover, the pharmacological inhibition of LSD1 using HCI-2509 reactivates a p53-associated gene expression signature while disrupting the MYCN transcriptional program [358]. Notably, both genetic and pharmacological inhibition of LSD1/KDM1A have been shown to induce autophagy [359]. Consistent with earlier findings showing that inhibition of G9a/GLP H3K9 methyltransferases induces autophagy in MYC-driven tumors, these observations suggest that MYC/MYCN, through interactions with histone methyltransferases and demethylases, selectively regulates autophagy in cancer cells, thereby providing a novel therapeutic approach.

Furthermore, LSD1/KDM1A has been reported to cooperate with MYCN to suppress expression of the metastasis suppressor MYCN downstream regulated gene 1 (NDRG1) [360]. Pharmacological inhibition of LSD1/KDM1A using TCP or SP2509 relieves MYC-mediated repression of NDRG1, thereby impairing the motility and invasiveness of NB cells [360]. Notably, induction of neuronal differentiation in MYCN-amplified cells is associated with decreased expression of LSD1/KDM1A and MYCN [360], suggesting LSD1/KDM1A as a promising target for differentiation therapy in this childhood tumor. Further supporting this notion, treatment with the LSD1/KDM1A inhibitor TCP in combination with all-trans-retinoic acid (ATRA) induces differentiation and impairs the engraftment of primary human AML cells in murine models, indicating that the combination may target leukemia-initiating cells (LICs) [361]. These findings led to a phase I dose escalation clinical trial (NCT02273102) evaluating TCP in combination with ATRA in adult patients with relapsed or refractory AML and myelodysplastic syndromes [362]. The TCP-ATRA combination demonstrated an acceptable safety profile, with clinical responses ranging from morphologic leukemia-free status in one patient to stable disease in two cases [362]. Notably, the combined treatment induced expression of ATRA target genes in responders but not in nonresponders, indicating that LSD1/KDM1A serves as a primary target for differentiation therapy [362]. In this regard, another LSD1/KDM1A inhibitor, iadademstat (ORY-1001), is in phase Ib clinical investigation in combination with azacitidine (DMNTi) and venetoclax (BCL-2i) (NCT06357182) in newly diagnosed patients with AML who are ineligible for intensive chemotherapy. Other histone demethylases have been shown to modulate the MYC-driven pathways. For example, the lysine demethylase 4 family A-C (KDM4A-C) specifically demethylates H3K9, H3K36, and H1.4K26, and has been shown to cooperate with MYCN in tumorigenic transcriptional programs [363].

In NB, amplification or overexpression of MYCN, through transcriptional and epigenetic reprogramming, drives tumor cells to transition from a mesenchymal (MES), neural crest-like state into an adrenergic (ADR), sympathetic neuron-like state [364, 365]. This MYCN-induced MES-to-ADR transition is accompanied by the induction of KDM4A-C, which, together with MYCN, regulates the expression of MYCN itself as well as the ADR core regulatory circulatory (CRC) transcription factors [366]. Pharmacological inhibition of KDM4A-C using QC6352 induces a genome-wide increase in H3K9me3, suppresses MYCN expression, downregulates the ADR CRC transcriptome, and exerts potent antitumor activity by inducing differentiation and apoptosis [366]. Further, QC6352 in combination with conventional chemotherapy (vincristine/irinotecan) resulted in complete tumor elimination in xenograft models of MYCN-amplified NB cells [366]. Importantly, KDM4B expression correlates positively with MYCN levels and serves as a marker of poor prognosis [367]. KDM4B physically interacts with MYCN at canonical MYCN target loci such as the miR-17~92 oncogenic cluster, Cell division cycle 25A, (CDC25A), Thyroid hormone receptor-interacting protein (TRIP13), and Versican (VCAN), enhancing transcription of these MYCN-regulated oncogenic programs [367]. This interaction culminates in reduced levels of H3K9me3/me2 repressive marks at target loci, thereby enhancing MYCN-mediated transcription of target genes [367]. In contrast, loss of KDM4B increases H3K9me2/3 at MYCN target promoters, reduces oncogenic transcription, impairs cell proliferation, induces differentiation, and suppresses tumor growth in vivo [367]. Supporting the therapeutic potential of targeting KDM4 family members, treatment of NB cell lines with ciclopirox, which targets multiple histone demethylases, including KDM4B, inhibited the MYC pathway, suppressed cell viability, induced differentiation, and inhibited tumor growth and dissemination in xenograft mouse models [368].

In castration-resistant PCa, KDM4B promotes tumor growth partly by enhancing androgen receptor (AR) mediated transcription of the MYC gene [369]. KDM4B inhibition reduces MYC expression and alleviates resistance to AR-targeted therapies [369]. Furthermore, KDM4B, in cooperation with MYC, promotes progression to castration-resistant PCa by enhancing the expression of MYC-regulated metabolic genes [370]. In GBM, KDM4B interacts with MYC, promoting a MYC gene expression program that accelerates tumor progression by impacting cell survival, proliferation, migration, and invasion capabilities [371]. Mechanistically, KDM4B enhances MYC oncogenic activity by inducing miR-181d-5p expression, targeting the SCF^FBXL3+CRY2 E3 ligase complex, which in turn promotes MYC protein stability [371].

Collectively, these studies clearly suggest histone demethylases, particularly KDM4B, as essential epigenetic regulators that cooperate with MYC and MYCN across multiple cancer types. Notably, ciclopirox selectively suppressed the growth of NB cell lines while sparing normal primary human fibroblasts [368], supporting its advancement in clinical settings.

Targeting the Epitranscriptome

N⁶-methyl adenosine (m⁶A) is the most abundant modification in eukaryotic mRNAs and noncoding RNAs, modulating multiple aspects of RNA metabolism, including splicing, export, stability, translation, and decay, thereby influencing gene expression [372]. The levels of m⁶A are finely tuned by a dynamic regulatory machinery consisting of “writer” methyltransferases [Methyltransferase-like 3 (METTL3), METTL14, and Wilms' tumor 1-associating protein (WTAP)] which install m⁶A,  the “eraser” demethylases [Fat mass and obesity-associated protein (FTO) and AlkB homolog 5 (ALKBH5) protein] which  remove m⁶A, and the “readers” [YTH domain-containing family proteins 1/2/3 (YTHDF1/2/3) and Insulin-like growth factor 2 mRNA-binding protein 1/2/3 (IGF2BP1/2/3)] which recognize m⁶A and direct RNA fate [372]. Aberrant expression of m⁶A components and altered m⁶A profiles are common in cancer, due to deregulation of oncogenic and tumor-suppressive programs that impact multiple hallmarks of cancer, including proliferation, differentiation, invasion, metabolic activity, and immune evasion [373].

Recent studies have demonstrated that MYC/MYCN influence mRNA m⁶A levels in several cancer types. For example, MYC has been shown to preferentially reduce m⁶A levels in transcripts of a subset of MYC-repressed genes, many of which are tumor suppressor genes, in B-cell lymphoma [374]. Mechanistically, MYC drives the expression of the m⁶A demethylases ALKBH5 and FTO, which counteract YTHDF3 binding to m⁶A-modified mRNAs and subsequent mRNA translation inhibition [374]. This study identified the MYC-ALKBH5-m⁶A-Spi-1 proto-oncogene (SPI1)/Plant homeodomain finger protein 12 (PHF12) axis as an oncogenic driver of cell proliferation and tumor progression [374]. Treatment of P493-6 lymphoma cells, either in vitro or in vivo with the ALKBH5 inhibitor IOX3, suppressed cell proliferation, increased SPI1 and PHF12 protein levels, and inhibited MYC-ALKBH5 regulation on MYC-mediated target gene repression [374].

In high-risk MYCN-amplified NB, elevated MYCN mRNA levels are maintained by Krüppel-associated box-associated protein 1 (KAP1), which protects the m⁶A reader YTH domain-containing protein 1 (YTHDC1) from degradation [375]. Notably, MYCN directly drives the transcription of KAP1 [375], suggesting the existence of a self-reinforcing regulatory loop that sustains MYCN expression. In agreement, KAP1 depletion downregulated YTHDC1 levels and promoted MYCN mRNA degradation, which negatively impacted tumor cell growth [375]. Given that KAP1 lacks enzymatic activity and primarily functions as a scaffold protein, no pharmacological inhibitors are currently available. Thus, the development of KAP1 degraders may provide a promising therapeutic target in MYC/MYCN-driven tumors.

In contrast, targeting METTL3, the catalytic subunit of the m⁶A methyltransferase complex, using the small-molecule inhibitor STM2457, reduced tumor growth in AML models, partly by reducing m⁶A on MYC mRNAs and suppressing MYC signaling [376]. In addition, the antitumor activity of STM2457 has been demonstrated in MYCN-amplified NB cells [375]. Notably, STM2457 treatment reduced MYCN levels without affecting KAP1 protein expression [376], suggesting that it suppresses MYCN expression without interfering with KAP1 activity on other mRNA targets. Furthermore, STM2457 treatment of NB cells has been shown to stabilize transcripts associated with neuronal differentiation and upregulate their expression [377].

Intriguingly, targeting METTL3 also induces double-stranded RNA (dsRNA) formation and a robust cell-intrinsic interferon response, thereby enhancing tumor immunogenicity and improving the efficacy of anti-PD-1 therapy [378]. These findings propelled the clinical evaluation of STM2457-derived compound STC-15 in a phase IB/II clinical trial in combination with the anti-PD-1 toripalimab for selected advanced solid tumors (NCT06975293). Considering the immune-suppressive functions of MYC/MYCN in cancer, investigating targeting METTL3 in combination with immunotherapies may represent a promising strategy to suppress the growth and progression of MYC/MYCN-driven tumors in preclinical models.

Moreover, inhibitors targeting the m⁶A demethylases, including FTO and ALKBH5, have shown potent anticancer activity in preclinical studies. For example, FB23-2, a small-molecule inhibitor targeting FTO demethylase activity, suppresses the proliferation of human AML cell lines and primary blast cells in vitro, while promoting cell differentiation and apoptosis [379]. Mechanistically, FB23-2 increases m⁶A levels and downregulates MYC-CCAAT/enhancer-binding protein alpha (CEBPA) signaling in AML models [379]. Similar antitumor effects and underlying molecular mechanisms have also been reported for preclinical inhibitors targeting m⁶A ALKBH5 as well as m⁶A readers, including IGF2BP and YTHDF family members [380].

Dual Epigenetic Inhibitors

Simultaneous dysregulation of multiple epigenetic pathways is a hallmark of cancer cells, leading to widespread epigenetic reprogramming that fuels tumor initiation, progression, and therapy resistance. Recent advances in epigenetic drug discovery have resulted in the development of dual epigenetic inhibitors that address the complexity by modulating complementary epigenetic targets within a single molecule, potentially enhancing therapeutic efficacy, reducing drug resistance, and minimizing toxicity compared with combination therapies [381, 382]. Consequently, dual inhibition represents a promising strategy in the development of next-generation epigenetic treatments for cancer. CM-272 is a first-in-class dual small-molecule which inhibits both G9a and DNMT activity, reduces cancer cell proliferation, induces interferon-stimulated genes, and promotes immunogenic cell death in AML, ALL, and lymphoma models [383]. Recently, dual BRD4/HDAC inhibitors were designed and synthesized through a pharmacophore fusion strategy on the basis of the BRD4 inhibitor ABBV-744 and the HDAC inhibitors vorinostat and entinostat [384]. These molecules exhibit both biochemical and cellular activity and induce cell cycle arrest and apoptosis in MV-4-11 B-myelomonocytic leukemia cells [384]. The antitumor activity and therapeutic potential of combined BRD4/HDAC inhibition are yet to be evaluated in preclinical cancer models. The development of dual epigenetic inhibitors that target HDACs and upstream oncogenic signaling has demonstrated potent antitumor effects when compared with single-target inhibition. For instance, CUDC-907, a dual inhibitor of HDAC and PI3K signaling, has shown potent antitumor effects in preclinical models of MYC/MYCN-driven tumors such as GRP 3 MB [385], AML [386], MM [387], and NB [388]. The encouraging findings have provided the rationale for clinical evaluation of CUDC-907 in lymphomas (NCT02674750, NCT01742988) and different solid tumors (NCT02909777, NCT03893487). CUDC-101 is a multi-HDAC+EGFR/HER2 inhibitor that has demonstrated potent antitumor effects using in vitro and in vivo models of NSCLC, liver, breast, head and neck, colon, and pancreatic cancers [389]. Early phase I clinical trial evaluating CUDC-101 on 25 patients with advanced solid tumors (NCT00728793) has demonstrated on-target effects, good tolerability, and preliminary evidence of antitumor activity [390]. In another study performed on twelve patients with intermediate or high-risk HNSCC (NCT01384799), combinations of CUDC-101, cisplatin, and radiation were feasible, but CUDC-101 was discontinued due to adverse effects [391].

Metabolic Pathways and Mitochondrial Biogenesis

As discussed above, oncogenic MYC drives extensive metabolic reprogramming in cancer by rewiring glycolysis, nutrient utilization, lipid metabolism, and mitochondrial function [53]. Consequently, MYC-driven metabolic alterations establish specific dependencies to which cancer cells become addicted; targeting these vulnerabilities can selectively impair tumor growth and induce tumor regression (Fig. 7).

Fig. 7.

Metabolic susceptibilities in MYC-driven cancers. Schematic representation illustrating the metabolic programs directly or indirectly upregulated by oncogenic MYC, contributing to tumorigenesis. High MYC activity drives an extensive metabolic reprogramming, altering many metabolic pathways, including glycolysis, oxidative phosphorylation (OXPHOS), fatty acid β-oxidation (FAO), fatty acid synthesis, and glutaminolysis, thereby supporting rapid proliferation and oncogene-induced stress. In addition, MYC-driven tumors show an increased dependency on tryptophan and vitamin B5 and suppress ferroptosis. Key enzymes highlighted in red represent MYC-associated vulnerabilities for which pharmacological inhibition (in light green rectangles) has shown antitumor activity. Designed using Biorender.com

Glycolysis

Many different cancer types preferentially metabolize glucose through aerobic glycolysis, resulting in lactate production even in the presence of sufficient oxygen, a phenomenon known as the Warburg effect, which is regulated by the lactate dehydrogenase A (LDHA) enzyme [392]. MYC, as well as HIF1α, directly regulates LDHA expression, enhancing glycolysis and diverting pyruvate away from mitochondrial oxidation [393]. The small-molecule LDHA inhibitor FX11 disrupts cancer cell metabolism by lowering ATP and inducing oxidative stress and cell death, while suppressing tumor growth and progression in xenograft models of lymphoma and pancreatic cancer [394]. A recent study characterized two compounds (6 and 21) derived from a succinic acid monoamide scaffold, which induce ATP depletion, oxidative stress, and suppress tumor growth in models of pancreatic cancer. Moreover, they demonstrate strong synergy upon oxidative phosphorylation (OXPHOS) inhibition, supporting the notion that targeting metabolic vulnerabilities represents a promising strategy against aggressive tumors [395].

Monocarboxylate transporters (MCTs) are responsible for the transport of monocarboxylates, including lactate, in cells. To prevent intracellular acidification resulting from elevated lactate production, MYC-driven tumors upregulate their expression. Exploiting this dependency, the MCT1 inhibitor AZD3965 has completed a phase I clinical trial, showing encouraging preliminary clinical activity, including a complete response in one patient with lymphoma (NCT01791595) [396].

Pyruvate dehydrogenase kinase (PDK) inhibits the pyruvate dehydrogenase complex (PDC), preventing pyruvate conversion to acetyl-CoA and its entry to the tricarboxylic acid (TCA) cycle, thereby maintaining glycolytic flux. Similar to LDHA, MYC and HIF1α cooperatively enhance PDK expression [397]. The PDK1 inhibitor dichloroacetate (DCA) has demonstrated antitumor activity in preclinical cancer models, and several clinical trials (NCT01111097, NCT05120284, NCT01386632) have been completed or are ongoing for the treatment of head and neck cancer and brain tumors, including GBM [398, 399]. However, its anticancer efficacy varies across tumor types and often requires high concentrations, reflecting differential sensitivity and isoform-specific PDK expression, with PDK2 being the most responsive to DCA-mediated inhibition. Furthermore, a recent study showed that the use of PROTACs directed against PDK1 reverses the Warburg effect, triggers immunogenic cell death, and sensitizes tumors to immune checkpoint blockade in vivo [400].

Other inhibitors that have shown promising preclinical data but remain to be clinically evaluated include the glucose transporter 1 (GLUT1) inhibitors BAY-876 [401] and WZB117 [402], which block glucose uptake and cell proliferation with high affinity, as well as the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) inhibitor PFK15, which disrupts glycolytic flux and induces cell cycle arrest and apoptosis [403].

Lipid Metabolism

We have demonstrated that both genetic and pharmacological inhibition of MYCN induces metabolic reprogramming, characterized by lipid droplet accumulation and neuronal differentiation in NB (Zirath et al., PNAS [458]). We subsequently showed that MYC inhibition in clear cell renal cell carcinoma (ccRCC) similarly induces a metabolic switch, as characterized by formation of lipid droplets [91]. In addition, we found that MYCN-amplified NB exhibit enhanced glycolysis and OXPHOS, preferentially relying on fatty acids as an energy source and displaying metabolic reprogramming characterized by elevated expression of antioxidant enzymes. We also found that targeting carnitine palmitoyl transferase 1 (CPT1), the rate-limiting enzyme of fatty acid β-oxidation (FAO), reduces tumor burden [404]. In parallel, inhibition of fatty acid synthesis through targeting fatty acid synthase (FASN) and acetyl-CoA carboxylase A (ACACA) decreases MYCN levels, promotes neuronal differentiation, and suppresses tumor growth [405]. Moreover, we identified the antioxidant enzyme peroxiredoxin 6 (PRDX6) as a promising therapeutic target in NB, as its inhibition reduces MYCN levels, induces apoptosis and neural differentiation, and synergizes with glutathione S-transferase Pi 1 (GSTP1) inhibition to suppress tumor growth in vitro and in vivo [406]. Similarly, another study reported that MYCN-amplified cells promote fatty acid uptake and synthesis, highly dependent on fatty acid uptake for survival. Inhibition of the fatty acid transport protein 2 (FATP2), encoded by SLC27A2, reduces tumor growth as a single agent and synergizes with conventional chemotherapeutic drugs in preclinical models [407]. Collectively, these findings highlight lipid metabolism as a key susceptibility in NB and a promising therapeutic target for further investigation, particularly in combination with existing and emerging therapies.

Another report demonstrated that MYC, together with sterol-regulated element-binding protein 1 (SREBP1), promotes tumorigenesis by driving fatty acid synthesis and reshaping the cellular lipidome across multiple preclinical cancer models. Pharmacological inhibition of lipogenesis using 5-tetradecyl-oxy-2-furoic acid (TOFA), an ACACA inhibitor, blocked tumor growth and induced tumor regression, highlighting lipid metabolism as a key vulnerability in MYC-driven cancers [408]. Moreover, lipid metabolic profiling identified FAO as a key dysregulated pathway in MYC-overexpressing TNBC. It has been demonstrated that inhibiting FAO by targeting CPT1 with etomoxir impaired energy metabolism and suppressed tumor growth in MYC-high TNBC models, highlighting FAO as a therapeutic vulnerability in this tumor subset [409]. The same group further demonstrated that MYC-high TNBC cells stimulated lipolysis in adjacent adipocytes via gap junction-mediated interactions, thereby supplying fatty acids that support tumor growth, and that disruption of this metabolic crosstalk represents an additional therapeutic opportunity [410].

Glutamine Metabolism

Glutamine is the primary carrier of nitrogen and the most abundant nonessential amino acid in the body [411]. Tumors with high MYC signaling often exhibit a depletion of TCA cycle intermediates due to elevated glycolytic flux. To compensate for this deficit, cancer cells rely heavily on glutamine as a carbon source, a phenomenon referred to as glutamine addiction [412, 413]. Glutamine-derived carbons enter the TCA cycle through conversion to glutamate by glutaminase (GLS), followed by further conversion to α-ketoglutarate via glutamate dehydrogenase (GDH) or transaminases. This process, known as glutaminolysis, functions as an anaplerotic pathway that sustains mitochondrial respiration and supports the energetic and biosynthetic demands of rapidly proliferating MYC-driven tumors [414]. MYC directly upregulates the expression of the glutamine transporter SLC1A5 (ASCT2), and indirectly, increases GLS expression by repressing microRNAs miR-23a/b [415, 416]. Consequently, targeting glutaminolysis represents a potential strategy to exploit this metabolic dependency. One of the first glutamine antagonists described was 6-diazo-5-oxo-L-norleucine (L-DON), which exhibited antitumor activity, but was limited by gastrointestinal toxicity [417]. Newer prodrugs derived from L-DON, such as JHU-083, are currently under investigation in preclinical models, demonstrating improved oral bioavailability, blood–brain barrier penetration, and notable efficacy against MYC-driven MB growth [418, 419]. Bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl)ethyl sulfide (BPTES), an allosteric GLS1 inhibitor, is widely used in preclinical studies but has limited clinical application due to its poor solubility and pharmacokinetics [420]. We have demonstrated that combining BPTES and OMOMYC expression further reduced tumor burden compared with either approach alone in a xenograft model of ccRCC, while also preventing lipid droplet accumulation [91]. These findings indicate that simultaneous inhibition of MYC activity and glutamine metabolism exerts synergistic antitumor effects by disrupting MYC-dependent metabolic reprogramming that supports tumor growth and lipid storage.

Limitations of earlier GLS inhibitors have driven the development of the more selective, orally bioavailable compound CB839, which exhibited a favorable safety profile in patients. Although its single-agent activity in solid tumors was limited, it showed a promising response when combined with azacytidine in myelodysplastic syndromes [421]. Recently, the first-in-class inhibitor iMQT-020, which targets the specific splice variant of SLC1A5 (SLC1A5_var) and impairs mitochondrial glutamine transport, was developed. This compound not only inhibits the growth of several cancer types, but also modulates PD-L1 expression in pancreatic cancer cells, supporting its potential use in combination with anti-PD-L1 antibodies [422].

Mitochondrial Metabolism and Biogenesis

MYC regulates genes related to mitochondrial metabolism and biogenesis [423]. Consequently, MYC inhibition has been shown to impair OXPHOS, reduce mitochondrial mass and function, and broadly rewire cellular metabolism, limiting the bioenergetic and biosynthetic capacity of cancer cells [424]. A recent genome-wide clustered interspaced short palindromic repeats (CRISPR) screening showed that MYC inhibition with the small-molecule inhibitor MYCi975 creates a selective vulnerability to mitochondrial complex I disruption using metformin. Both genetic and pharmacological targeting of complex I enhanced sensitivity to MYCi975 and promoted infiltration of CD8⁺ T cells and macrophages into tumors [84]. Similarly, another study reported that cancer cells with deregulated MYC levels are particularly sensitive to the human N-myristoyltransferases (NMTs) inhibitor IMP-1320, which induces cell death associated with loss of mitochondrial respiratory complex I proteins. NMT inhibition suppressed or eradicated MYC/MYCN-driven tumors in vivo without evident toxicity, highlighting their potential as a novel targeted therapy [425].

In MYC-driven NB, targeting mitochondrial translation results in cell death as demonstrated by inhibition of mitoribosome function with doxycycline and disruption of mitochondrial fission with Mdivi-1 [426].

Other Amino Acid and Vitamin Metabolism

Cysteine is the rate-limiting amino acid for glutathione synthesis, a critical regulator in cellular redox homeostasis. In MYCN-amplified NB, cysteine depletion induces lipid peroxidation, sensitizing cells to iron-dependent death (ferroptosis). Simultaneous targeting of cystine uptake and the transsulfuration pathway in combination with inactivation of the antioxidant enzyme glutathione peroxidase 4 (GPX4) led to tumor remission in an orthotopic model of NB, supporting the simultaneous targeting of multiple ferroptosis regulators as a promising therapeutic strategy against this aggressive childhood cancer [427].

Tryptophan is an essential amino acid that can be converted into serotonin or catabolized via the kynurenine pathway. Liver tumors with elevated MYC expression depend on increased tryptophan uptake, which is preferentially metabolized into indole-3-pyruvate (I3P) rather than classical kynurenine metabolites. In this context, I3P promotes tumor growth, and restricting tryptophan in the diet limits tumor progression, revealing a metabolic vulnerability in MYC-high liver cancers [428].

Similarly, a recent study reported that in mammary tumors, regions with high MYC expression accumulate elevated levels of pantothenic acid (vitamin B₅), due to direct upregulation of its transporter SLC5A6. Its overexpression drives tumor proliferation, whereas restricting pantothenic acid intake reverses MYC-mediated metabolic reprogramming and suppresses tumor growth [429].

Targeting Metabolic Plasticity

MYC promotes both glycolysis and mitochondrial OXPHOS, providing cancer cells with high metabolic plasticity. The antihypertensive drug syrosingopine has been repurposed as a cancer metabolic inhibitor, blocking lactate transport and disrupting redox homeostasis in tumor cells. Two studies have reported that combining syrosingopine with inhibitors of mitochondrial metabolism, such as UK-5099 or metformin, creates synthetic lethality by simultaneously blocking glycolysis and OXPHOS compensation. Syrosingopine and UK-5099 synergistically suppress NSCLC by inducing cell cycle arrest, apoptosis, and mitochondrial damage through lactate accumulation and oxidative stress, which triggers an integrated stress response (ISR) and results in robust tumor suppression in vitro and in vivo [430]. In MM, the combination of syrosingopine with metformin activates AMP-activated protein kinase (AMPK) signaling, reduces protein synthesis, and robustly limits tumor growth [431].

Tumors driven by MYC tolerate high levels of oxidative stress by, in part, upregulating nuclear factor erythroid 2-related factor 2 (NRF2)-dependent antioxidant programs that protect cancer cells from ROS accumulation [432]. A key NRF2-regulated antioxidant pathway is the thioredoxin system, comprising thioredoxin and thioredoxin reductase 1 (TrxR1), frequently overexpressed across multiple human cancers, including MYC-overexpressing high-grade serous ovarian carcinoma (HGSOC) [433]. Inhibition of TrxR1 with auranofin suppresses glycolysis, forcing metabolic rewiring that increases their dependence on glutamine as an alternative energy source. Combination treatment with auranofin and the glutaminase inhibitor CB-839 shows a synergistic effect in vitro and in vivo models of HGSOC, resulting in robust tumor growth suppression [433].

Given the broad role of MYC in regulating cellular metabolism, tumors with activated MYC expression exhibit high metabolic flexibility, which often limits the efficacy of single-agent therapies. The abovementioned preclinical studies demonstrate that simultaneous targeting of glycolysis and compensatory pathways can prevent this metabolic adaptation, creating an “energy crisis” and producing synergistic antitumor effects. Accordingly, future therapeutic strategies should focus on rational combination approaches to exploit the metabolic vulnerabilities of MYC-driven tumors, prevent compensatory adaptations, and achieve more durable and effective antitumor responses.

MYC as a Regulator of Tumor Immune Evasion

During cancer initiation and progression, tumor cells are actively communicating with stromal and immune cells through cytokines, growth factors, and extracellular vesicles, promoting proliferation, survival, and in later stages, invasion and metastasis. In this context, MYC functions as a critical orchestrator of the TME, contributing to its remodeling into a more permissive niche through modulation of stromal interactions, immune evasion, and metabolic reprogramming, supporting tumor growth. Several studies have described that impacting MYC function in tumors interferes with their ability to evade immune surveillance.

The first immune evasion strategy that was described as being governed by MYC was the suppression of neoantigen preparation and presentation. This process is controlled by major histocompatibility class I and II (MHC-I and II) molecules that present intracellular peptides to cytotoxic T cells, enabling the immune system to detect pathological changes such as infection or oncogenic transformation, leading to their elimination. Elevated MYC expression is associated with reduced antigen presentation due to the suppression of both MHC-I and II in multiple cancer types [70, 72, 434, 435]. Conversely, MYC inhibition or depletion restores the expression of antigen presentation machinery, enhancing tumor immunogenicity, and promoting their recognition by T cells [71].

In addition, MYC promotes immune evasion through coordinated regulation of immune checkpoint molecules and remodeling of the TME. For instance, MYC directly promotes the expression of PD-L1 and CD47 [71]. In lymphomas, downregulation of MYC is associated with a decrease in PD-L1 levels, leading to tumor regression in immunocompetent mouse models of the disease. CD47 functions as a major innate immune checkpoint by delivering a “do not eat me” signal to macrophages and other myeloid cells through interaction with signal regulatory protein alpha (SIRPα) [436]. MYC has been shown to directly bind the CD47 promoter and activate its transcription in lymphoma models, enabling tumor cells to escape phagocytic clearance by the innate immune system [71].

Moreover, deregulated expression of MYC in tumors induces the expression of inhibitory cytokines and chemokines, reshaping the TME and facilitating immune evasion. For example, in a mouse model of pancreatic cancer, MYC activation in β cells promotes the rapid expression and release of the proinflammatory cytokine interleukin 1β (IL-1β), triggering the rapid onset of angiogenesis. Furthermore, MYC activation rapidly promotes the expression of CCL2 and CCL5, associated with infiltration of mast cells, followed by the onset of tumor angiogenesis by macrophages and neutrophils [437]. In addition, MYC cooperates with mutant KRAS^G12D to suppress the type I interferon (IFN) pathway through MYC-MIZ-1-mediated repression of key IFN regulators, including interferon regulatory factor 5 (IRF5), IRF7, signal transducer and activator of transcription 1 (STAT1), and STAT2. This suppresses NK- and B-cell infiltration, promoting immune evasion and tumor progression in preclinical models, while restoration of IFN signaling may represent a promising therapeutic strategy in PDAC. A recent study using a reversible KRAS^G12D-driven pancreatic cancer mouse model with switchable MYC activity demonstrated that MYC inhibition induces rapid PDAC regression. This was mediated by the transient release of granulocyte-macrophage colony-stimulating factor (GM-CSF) and recruitment of conventional type 1 dendritic cells (cDC1s), resulting in stromal collapse and antitumor immune responses. These findings identify GM-CSF–cDC1 signaling as a key mediator of MYC-dependent tumor maintenance and a potential therapeutic target in PDAC [438].

In a preclinical model of TNBC, MYC cooperates with MIZ-1 to suppress innate immune signaling and immune cell recruitment by repressing IFN signaling as well as the chemokines CCL5 and CXCL10. These effects impair stimulator of interferon genes (STING)-mediated antitumor immunity, reduce immune cell infiltration, and promote immune evasion [439]. In HCC, MYC and MIZ-1 repress the expression of MHC-I. Importantly, MYC-driven immunosuppression could be reversed by combined PD-L1 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) blockade, which induced proinflammatory macrophage activation, enhanced antigen presentation, and restored effective antitumor immunity, highlighting the therapeutic potential of targeting immune checkpoint pathways in MYC-driven tumors [440]. Moreover, the cooperation of MYC and TWIST1 in a mouse model of HCC induces the secretion of CCL2 and IL-13 that leads to the recruitment and polarization of tumor-associated macrophages (TAMs), promoting metastasis [441].

MYC activation has been shown to rapidly drive progression to aggressive, invasive adenocarcinoma characterized by a highly inflammatory, angiogenic, and immunosuppressed stroma in a KRAS^G12D-driven mouse lung adenoma model. This is mediated by tumor-derived CCL9 and IL-23, which reprogram the microenvironment by recruiting macrophages, inducing angiogenesis, and promoting the exclusion of B, T, and NK cells. Blocking both CCL9 and IL-23 prevents MYC-driven tumor progression, while MYC inactivation in established tumors leads to rapid tumor regression, dependent on NK cell infiltration [51]. A more recent study using the same mouse model revealed that inactivation of oncogenic MYC triggers a rapid, tissue-intrinsic immune response mediated by epithelial release of IL-33. This signal reverses immunosuppression and angiogenesis, promotes eosinophil recruitment, and drives elimination of tumor cells in this model. The authors demonstrated that MYC inactivation can drive resolution of established tumors by engaging intrinsic innate immune response [442]. However, as illustrated by the studies discussed above, how MYC regulates the tumor immune microenvironment is highly dependent on the tumor type and concomitant mutations. Increasing evidence indicates that MYC does not act alone but rather cooperates with additional factors to shape distinct immune composition and evasion programs. For instance, while MYC has been reported to directly regulate immune checkpoint molecules such as PD-L1 and CD47 in some settings, these mechanisms are not observed in KRAS/p53-driven mouse models of PDAC [70].

MYC-Driven Reprogramming of Cancer Metabolism and Immune Suppression

Metabolic reprogramming in tumors shapes the immune microenvironment by altering nutrient availability and accumulating metabolites that can suppress or modulate immune cells. This may impair antitumor immune responses and contribute to immune evasion in a context-dependent manner. Thus, it is not surprising that the wide-ranging role of MYC in reprogramming cancer cell metabolism can have major consequences for immune regulation in tumors (Fig. 8).

Fig. 8.

MYC promotes an immunosuppressive immunosuppressive TME by combining metabolic and epigenetic effects. Left panel: Elevated levels of MYC promote immune evasion through a combination of different metabolic and epigenetic alterations in cancer cells. The MYC-driven metabolic alterations include the release of immunosuppressive metabolites, such as lactate, kynurenine, and lipids, thereby limiting nutrient availability for immune cells due to increased uptake of glucose, glutamine, and tryptophan. These changes contribute to T-cell exhaustion, polarization of macrophages toward an immunosuppressive M2 phenotype, expansion of myeloid-derived suppressor cells (MDSCs) as well as regulatory T cells (Tregs), and reduced antigen presentation by dendritic cells. In parallel, MYC-associated epigenetic programs suppress interferon (IFN) signaling and chemokine expression, including CXCL9 and CXCL10, leading to impaired T-cell recruitment and reduced MHC-I-mediated antigen presentation. MYC-driven expression of CXCL1, CXCL5, and CCL20 further promotes recruitment of immunosuppressive MDSCs. Right panel: MYC-targeting strategies restore metabolic homeostasis and epigenetic repression programs, thereby promoting inflammation and an antitumorigenic TME. Designed using Biorender.com

As described above, MYC promotes glucose metabolism toward lactate production through upregulation of glycolytic enzymes. The resulting accumulation of lactate acidifies the tumor milieu, which can impair immune cell function and contribute to immunosuppressive conditions in the TME [443]. In parallel, lactate has been reported to disrupt antigen presentation by dendritic cells, partly by inhibiting their differentiation and limiting MHC-dependent antigen presentation [444]. Lactate has been associated with the expansion of immunosuppressive myeloid-derived suppressor cells (MDSCs) and driving recruitment and polarization of tumor-associated macrophages toward an M2-like phenotype in a preclinical pancreatic cancer model [445]. In addition, lactate signaling through its receptor G protein-coupled receptor 81 (GPR81) can reinforce immune evasion by upregulating PD-L1 on lung tumor cells, further suppressing dendritic cell activity, and attenuating T-cell function in a paracrine manner [446].

MYC-driven tumors are often addicted to glutamine, resulting in enhanced glutaminolysis and depletion of extracellular glutamine. This metabolic competition may limit glutamine availability for immune cells, thereby potentially impairing the function of glutamine-dependent populations such as effector T cells and dendritic cells, as observed in a model for metastatic melanoma [447]. In parallel, some MYC-high tumors showed an increase in tryptophan catabolism, leading to depletion of tryptophan and accumulation of kynurenine, which in turn promotes T-cell dysfunction and apoptosis, expanding regulatory T cells and suppressing NK cell cytotoxicity and cytokine production [448, 449]. Kynurenine can additionally impair dendritic cell maturation and antigen presentation and activate aryl hydrocarbon receptor (AHR)-dependent immunosuppressive transcriptional programs.

Notably, MYC-induced changes in lipid metabolism could critically shape the immune tumor compartment by generating immunosuppressive lipid species and disrupting immune cell function. Accumulation of fatty acids, cholesterol, and oxidized lipids is associated with impaired dendritic cell and macrophage function by inducing ER and oxidative stress, disrupting lipid raft-dependent antigen presentation, and promoting immunosuppressive cytokine production. In addition, lipid signaling pathways, including peroxisome proliferator-activated receptor (PPAR) activation and lysophospholipid signaling, could lead to the polarization of macrophages toward a more tumor-promoting phenotype and impair immune cell migration and activation.

The abovementioned small-molecule inhibitors targeting MYC-driven metabolic vulnerabilities may therefore contribute to attenuation of tumor immune evasion by mitigating nutrient depletion and reducing the accumulation of immunosuppressive metabolites (Fig. 8). Inhibition of MYC-dependent glycolysis, glutaminolysis, lipid biosynthesis, and amino acid catabolism could potentially lower lactate levels, restore amino acid availability, and prevent the production of lipid mediators that suppress immune function. As a result, effector T and NK cells may regain metabolic fitness and cytotoxic capacity, while dendritic cells could recover antigen-presenting function. At the same time, inhibiting signals induced by metabolites could decrease the recruitment and polarization of immunosuppressive cells such as TAMs and MDSCs. Importantly, while targeting MYC-driven metabolic programs can result in modulation of tumor-immune interactions in preclinical models, the extent to which these approaches reverse immune evasion is context-dependent and tumor-type specific, and further research is needed to establish their potential translational relevance.

Epigenetic Control of Immune Suppression in MYC-Driven Cancers

Emerging evidence using preclinical models of MYC/MYCN-driven as well as other human cancer types suggests that context-dependent epigenetic mechanisms may contribute to suppression of immunosurveillance by decreasing the expression of immunomodulatory pathway genes and tumor antigen presentation mechanisms impacting both innate and adaptive immune responses (Fig. 8). Consequently, clinical trials evaluating epigenetic therapies in combination with immunotherapy approaches have gained momentum [450, 451]. In NB, the epigenetic core regulatory circuits defining the ADR- or MES-phenotypes significantly impact innate immune responses via modulating the cyclic GMP-AMP synthase (cGAS)-STING and Toll-like receptor 3 (TLR3) pathways, which mediate cytosolic DNA and dsRNA sensing, respectively [452]. This study suggests that human NB cells with stronger MES-epigenetic signatures possess a higher basal inflammatory state, which enhances T-cell mediated tumor killing in an in vitro experimental setting [452]. In addition, MYCN-amplified NBs are considered to be immune cold tumors. It has been suggested that the histone-lysine methyltransferases EHMT2 (G9a), EHMT1 (GLP), and EZH2 drive this phenotype by repressing the expression of IFN-γ response genes such as C-X-C motif chemokine ligand 9 (CXCL9), CXCL10, key factors of T-cell recruitment into the TME, as well as genes in the MHC class I antigen presentation machinery [453]. Moreover, the HDACi entinostat has been shown to enhance the expression of MHC class I genes in high-risk NB cells, increasing the expression of transporter associated with antigen processing 1/2 (TAP1/2) and immunoproteasome subunits regulating T-cell cytotoxicity, as well as MHC class I polypeptide-related sequence A and B (MICA and MICB), which are important in NK cell cytotoxicity [454].

In breast cancer gene 1/2 (BRCA 1/2)  deficient TNBC, MYC overexpression correlated with loss of immune signatures by repressing the expression of multiple interferon-signaling genes in a MIZ-1 dependent manner [439]. Furthermore, MYC overexpression also suppressed the expression of STING by blocking enhancer acetylation, resulting in downregulation of the T-cell chemokines CCL5, CXCL10, and CXCL11, which in turn hampered the efficacy of PD-L1 blockade. Notably, targeting MYC combined with PD-L1 blockade elicited a durable response in mouse models of TNBC [455]. Furthermore, DNMTs and HDACs have been shown to enhance MYC-mediated immunosuppression in KRAS^G12D NSCLC mouse model by inhibiting an INFα/β-based transcriptional program, as well as the antigen presentation machinery [456]. The combination of DNMTi and HDACi reduced MYC expression and increased CCL5 levels, as well as the percentage of CD8⁺ TILs in tumors of treated mice. Additional evidence highlighting epigenetic regulation of tumor immunity comes from studies of METTL3, a core enzyme for RNA m⁶A modification. This enzyme enhances MYC stability, and promotes the expression of pro-tumorigenic chemokines, including CXCL1, CXCL5, and CCL20, and destabilizes PD-L1 mRNA, thereby shaping a noninflammatory TME in NSCLC models [457]. Furthermore, the study shows that METTL3 inhibition enhances the efficacy of anti-PD-1 therapy in murine lung tumor models [457].

These findings support a role for epigenetic regulators in shaping immune-related phenotypes in MYC/MYCN-driven tumors. However, the extent to which these mechanisms operate across tumor types and their therapeutic relevance remains to be elucidated, as much of the evidence is derived from preclinical models. The ongoing clinical trials will provide insights into how epigenetic mechanisms regulate tumor immunity and shed light on the therapeutic window of using epigenetic therapies in combination with immunotherapy. This will also give guidance on defining the conditions under which a particular epigenetic therapy may be beneficial for patients with cancer.

Conclusions and Future Perspectives

Current strategies targeting the MYC oncoproteins represent one of the most active yet challenging areas in cancer therapy, as their structural properties and pervasive role in normal cellular function make direct inhibition difficult. Although preclinical studies and early clinical trials have demonstrated significant potential, translating these strategies into safe and effective therapies remains a major hurdle due to issues related to specificity, delivery, and systemic toxicity. Despite these challenges, ongoing research integrating multiple targeting strategies with precision medicine approaches holds promise for effective management of MYC-driven cancers and may enable therapies that selectively inhibit tumor growth without compromising normal cellular functions.

Inhibiting MYC:MAX interactions using peptides and small molecules represents the most rational and direct approach to attenuating MYC oncogenic activity to date. The development of peptide inhibitors targeting MYC:MAX dimerization has demonstrated promising therapeutic value in MYC-targeted cancer therapies. This is exemplified by the rapid clinical progression of OMO-103 in aggressive and advanced solid tumors, including PDAC (NCT07089940, NCT06059001), NSCLC, TNBC, CRC (NCT04808362), and advanced high-grade osteosarcoma (NCT06650514). The promising results of the phase I clinical trial of OMO-103, demonstrating stable disease, target engagement, and minimal adverse effects, support the evaluation of OMO-103 as a front-line treatment in combination with standard-of-care therapy. However, peptide and mini-protein-based therapies suffer from some significant limitations, such as poor stability and limited absorption across the intestinal lining, which restricts their oral bioavailability. Consequently, peptide-based MYC inhibitors are typically delivered via intravenous or other parenteral routes in both preclinical and clinical settings. Continued research aimed at improving formulation strategies and delivery methods may enhance the stability and bioavailability of anti-MYC peptide inhibitors, thereby increasing their therapeutic efficacy.

In parallel, advances in high-throughput screening, structure-based drug design, and computational modeling have facilitated the identification and development of high-affinity small-molecule compounds capable of selectively disrupting MYC:MAX interaction and suppressing tumor growth in a MYC-dependent manner. For example, MYCi361, a lead small-molecule inhibitor of MYC:MAX dimerization, inhibits MYC-driven transcription, suppresses tumor growth in vivo, enhances tumor immune cell infiltration, and sensitizes tumors to anti-PD-1 immunotherapy in preclinical models. These findings position MYCi361, and its improved, second-generation analog MYCi975, as a promising anti-MYC therapeutic candidate that warrants further clinical validation. Further, PROTACs represent an emerging class of small molecules that induce selective degradation of oncogenic drivers by recruiting target proteins to E3 ubiquitin ligases, thereby promoting their ubiquitination and subsequent proteasomal degradation. PROTACs offer several key advantages, including the ability to target previously “undruggable” proteins, overcome resistance-associated mutations, and achieve sustained therapeutic effects through protein degradation rather than transient inhibition.

When compared with peptide inhibitors, small-molecule-based strategies to target MYC:MAX dimerization as well as MYC PROTACs present additional clinical advantages. For example, small-molecule inhibitors typically enter cells via passive diffusion, often exhibit oral bioavailability, and can be produced using established medicinal chemistry approaches, making them economically viable candidates for oncology applications. However, several challenges remain, including potential off-target effects, the possible emergence of resistance mechanisms, and limited long-term clinical data regarding safety and efficacy. Overall, small-molecule strategies may still represent one of the most promising frontiers in anti-MYC therapy, and their continued development will benefit advances in medicinal chemistry and improved structure-guided drug design.

Indirect MYC targeting strategies are likely to remain highly relevant, as MYC-driven tumors exhibit a strong dependency on transcriptional and epigenetic machinery. Inhibitors of key regulators such as CDK7, CDK9, BRD4, EZH2, G9a, and other super-enhancer-associated proteins have demonstrated synthetic lethality in the context of MYC overexpression. Dual epigenetic therapies have gained momentum to disrupt oncogenic transcriptional programs more effectively. The main advantages of combined epigenetic targeting include synergistic antitumor activity, reduced likelihood of resistance compared with single-agent therapy, and simplified treatment regimens compared with traditional drug combinations. However, disadvantages include an increased risk of overlapping toxicities, challenges in dose optimization to balance dual inhibitory activity, and the complexity of identifying predictive biomarkers. Future research will focus on identifying robust prognostic biomarkers to stratify patients most likely to benefit from these therapies. Advances in single-cell sequencing and spatial transcriptomics will further enhance our understanding of intratumoral MYC heterogeneity, guiding more precise and personalized epigenetic interventions.

Another important frontier lies in exploiting MYC-induced metabolic vulnerabilities. MYC-driven tumors frequently display increased dependence on glutamine metabolism, nucleotide biosynthesis, ribosome biogenesis, and mitochondrial function. Importantly, many of these MYC-driven altered metabolic programs are required to sustain oncogene-induced stress and rapid proliferation, which makes MYC-addicted tumors particularly vulnerable to metabolic perturbation. Targeting these metabolic liabilities could offer a tumor-selective therapeutic window while sparing normal cells, as pharmacological disruption of key metabolic pathways can selectively impair proliferation, induce cell death, and limit metabolic adaptation in MYC-high cancers. Integration of metabolomics and functional genomics will help in refining these approaches and reveal context-specific metabolic dependencies. Moreover, metabolic targeting may reshape the TME by altering nutrient availability and immune cell function, potentially enhancing antitumor immunity. In this context, rational combination strategies pairing MYC-pathway inhibitors with chemotherapy, targeted therapy, or immunotherapy may help to overcome resistance mechanisms and enhance the durability of therapeutic responses.

Collectively, these findings suggest that MYC-targeted therapies may show antitumor effects not only through direct inhibition of cancer cell proliferation and survival, but also by reshaping the composition of the immune system within the tumor. MYC inhibition can reverse immunosuppressive programs, restoring interferon signaling, antigen presentation, and immune cell recruitment, thereby enhancing both innate and adaptive antitumor immunity. Notably, MYC blockade has been shown to promote infiltration and activation of immune populations such as NK cells, dendritic cells, macrophages, eosinophils, and cytotoxic T cells. In addition, the immunomodulatory effects of MYC are context-dependent and can vary across tumor type, tissue context, and genetic alterations. Thus, the mechanisms by which MYC regulates the immune system in tumors, as well as the consequences of MYC-targeted therapies in the immune environment, should be investigated in a cancer-specific manner. Importantly, the impact of targeting MYC in the immune component may also sensitize tumors to immunotherapies, highlighting the therapeutic potential of combining MYC-targeted approaches with immune-based strategies.

In conclusion, targeting MYC oncoproteins has emerged as a compelling strategy in cancer therapy, from direct inhibition to exploiting MYC-dependent vulnerabilities. While clinical application remains challenging, these approaches have uncovered critical tumor dependencies and guided innovative combination strategies. With advances in biomarker-driven selection, targeted delivery, and rational drug design, MYC-directed therapies are poised to transform treatment for aggressive, previously untreatable cancers, offering a new paradigm for precision oncology, which will be beneficial for patients with diverse cancer types.

Funding

Open access funding provided by Karolinska Institute. The research in the Arsenian Henriksson Lab is funded by grants from Karolinska Institutet Research Funds [LSA (2024-02878), MA (2024-02968), & MAH (2024-03105)], the Lilian Sagen and Curt Ericsson Research Foundation [MA (2024-02)], the Swedish Cancer Society [MAH (25 4806 Pj)], the Swedish Childhood Cancer Fund [MAH (PR2024-0126)], the Cancer Research Foundations of Radiumhemmet [MAH (24 1103)], and the Swedish Research Council [MAH (32024-03253)]. LSA is supported by a postdoctoral position from the Swedish Society for Medical Research (PG-24-0412-H-01).

Declarations

Conflict of Interest

Lourdes Sainero-Alcolado (LSA), Dilraj Lama (DL), Mohammad Alzrigat (MA), and Marie Arsenian-Henriksson (MAH) declare that they have no conflicts of interest that might be relevant to the contents of this manuscript.

Ethics Approval

Not applicable.

Consent to Participate

Not applicable.

Consent for Publication

Not applicable.

Availability of Data and Material:

Not applicable.

Code Availability

Not applicable.

Author Contributions

LSA, DL, and MA wrote the manuscript with input from MAH. LSA, DL, and MA made the Figures. MAH contributed to manuscript design and revision. All authors approved the final version.

Data Availability

No datasets were generated or analyzed during the current study.