The dual facets of MiRNA in modulating NF-κB in breast cancer

Abstract

Background

Breast cancer (BC) remains a leading cause of cancer-related mortality among women globally, especially among women aged 45-55 years. A key driver of tumor progression, metastasis, and therapy resistance in BC is the aberrant activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), a proinflammatory transcription factor. Concurrently, microRNAs (miRNAs), a class of small non-coding RNAs, have emerged as critical post-transcriptional regulators of gene expression, influencing oncogenesis, immune response, apoptosis, and therapeutic outcomes.

Main body

Studies have revealed a complex interplay between miRNAs and NF-κB, wherein miRNAs exhibit context-dependent roles, functioning as either tumor suppressors or oncogenic regulators that modulate NF-κB signaling through direct or indirect mechanisms, modulating NF-κB signaling via direct or indirect mechanisms. This dual regulatory capacity presents unique therapeutic opportunities to either suppress oncogenic NF-κB signaling through tumor suppressor miRNAs (TS-miRs) or inhibit oncogenic miRNAs (OncomiRs) that potentiate NF-κB activity. This review presents a comprehensive overview of how miRNAs modulate NF-κB pathways in BC, outlines recent preclinical advances in miRNA delivery technologies, and discusses the clinical implications of miRNA-based therapeutics.

Conclusion

We emphasize the translational potential of miRNAs as emerging therapeutic modalities and predictive biomarkers for the personalized management of BC.

Graphical abstract

Background

Breast cancer (BC) is the most frequently diagnosed cancer among women and a leading cause of cancer-related mortality worldwide, with over 2.3 million new cases annually. Despite advancements in detection and therapy, BC continues to present clinical challenges due to its molecular heterogeneity and frequent development of treatment resistance. Aberrant activation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway plays a key role in BC progression by promoting proliferation, invasion, metastasis, and resistance to apoptosis, particularly in highly aggressive subtypes like triple-negative breast cancer (TNBC).

MicroRNAs (miRNAs), small non-coding RNAs approximately 22 nucleotides in length, have emerged as crucial post-transcriptional regulators of gene expression and key players in cancer development. Depending on their targets, miRNAs can act as tumor suppressors (TS-miRs) or oncogenic miRNAs (oncomiRs), with dysregulated expression contributing to BC progression and therapy resistance. Notably, miRNAs and NF-κB exhibit a complex, bidirectional relationship: miRNAs can directly or indirectly modulate NF-κB signaling, while NF-κB can influence miRNA expression, creating regulatory feedback loops that shape tumor behavior.

Understanding this interplay offers opportunities for innovative miRNA-based therapies aimed at modulating NF-κB activity. Recent advances in delivery systems, such as nanoparticles and extracellular vesicles, have enhanced the translational potential of miRNA therapeutics, highlighting the importance of elucidating miRNA-NF-κB interactions to improve outcomes for BC patients.

Introduction

Despite the high five-year survival rate, breast cancer (BC) continues to be a leading cause of cancer-related mortality among women worldwide [1, 2]. In 2022, BC among females represented the second most prevalent malignancy globally, with approximately 2.3 million newly diagnosed cases, constituting about 11.6% of total cancer incidences. Furthermore, it ranked as the fourth leading cause of cancer-related mortality worldwide, accounting for nearly 666,000 deaths and representing 6.9% of all cancer-related fatalities [1]. The inherent heterogeneity of this disease, both intertumoral and intratumoral, stands as a significant obstacle to developing effective treatment strategies [3]. Moreover, the dynamic plasticity of the tumor microenvironment further complicates patient responses to therapy [3]. The modulation of numerous signaling pathways has been shown to influence the progression and management of various chronic diseases, including cancer [4–7]. The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is one such signaling pathway, a family of transcription factors (TFs) essential for regulating cell proliferation, immune responses, survival, and inflammation [8, 9]. The NF-κB signaling pathway participates in a diverse physiological and pathological processes, including inflammatory conditions, autoimmune diseases, and cancer [8, 10].

Aberrant activation of the NF-κB pathway drives cancer progression by promoting angiogenesis, stimulating uncontrolled cell proliferation, suppressing apoptosis, and facilitating metastatic dissemination [11, 12]. NF-κB is often persistently activated in BC, promoting a more aggressive tumor phenotype and contributing to resistance against therapies such as chemotherapy and radiotherapy [13–15]. Although the exact mechanisms by which NF-κB contributes to BC progression are not fully understood; however, it is well-established that NF-κB governs the transcriptional activity of numerous genes involved in key processes of breast carcinogenesis [13]. Evidence indicates that NF-κB signaling enhances the survival of cancer cells under therapeutic stress by inhibiting apoptosis, thereby contributing to the development of treatment resistance [16]. This pathway also influences the tumor microenvironment, promoting inflammation, angiogenesis, and even the spread of cancer to distant organs [17]. It is associated with poor patient outcomes, particularly in highly aggressive subtypes like the triple-negative breast cancer (TNBC), where it has been linked to drug resistance [18–20]. Hence, targeting the NF-κB pathway holds promise as a therapeutic strategy, as inhibition of this signaling can reduce tumor growth and sensitize cancer cells to treatments.

Noncoding RNAs (ncRNAs) are crucial in cancer regulation, acting as either oncogenes or tumor suppressors [21–23]. Dysregulated expression of ncRNAs and their subsequent signaling have direct implications for cancer progression. ncRNAs represent a broad class of RNA molecules that are not translated into proteins but play crucial roles in gene regulation and cellular function. Among the major categories of ncRNAs are transfer RNA-derived small RNAs, microRNAs (miRNAs), and Piwi-interacting RNAs (piRNAs), each having distinct biological functions. Additionally, long non-coding RNAs (lncRNAs) represent a heterogeneous group of ncRNAs longer than 200 nucleotides and include circular RNAs (circRNAs) and pseudogenes [24–26]. On the other hand, miRNAs are short ncRNAs of approximately 22 nucleotides that regulate gene expression by base pairing between the 5′ seed region of the miRNA and complementary sequences within the 3′UTR of target mRNAs [24, 25]. They either promote mRNA degradation or inhibit translation, thereby precisely regulating the transcriptional output of a broad spectrum of genes implicated in essential cellular processes. Since the discovery of miRNAs’ involvement in cancer in 2002, several studies have explored their biological functions, their dysregulation in various diseases, and their potential as therapeutic targets [27]. The identification of circulating miRNAs as novel biomarkers for cancer detection, along with the investigation of miRNAs involved in carcinogenesis, are the two primary focal points of miRNA-based cancer research [27, 28]. MiRNAs associated with carcinogenesis can be divided into two distinct subgroups: tumor suppressor miRNAs (TS-miRs) and oncogenic miRNAs (OncomiRs) [27].

In addition, several miRNAs are ambivalent in nature, where they function as oncomiRs in certain cancer types while functioning as tumor suppressors in others [27]. miRNAs have long been recognized as key regulators of NF-κB signaling, exerting significant influence on its activation and repression across various physiological and pathological contexts (Fig. 1). Their ability to exert dual regulatory effects on NF-κB activity presents a unique and promising opportunity for targeted therapeutic strategies in cancer, including BC, where aberrant NF-κB signaling is closely associated with tumor progression and resistance to therapy. One strategy involves restoring the function of TS-miRs to inhibit NF-κB signaling. For instance, introducing miRNAs like miR-30b-5p and miR-621 into BC patients can suppress NF-κB activity, leading to reduced tumor growth, invasion, metastasis, and sensitizing BC to chemotherapy, offering a targeted and efficient method to modulate NF-κB signaling in BC [29, 30]. Alternatively, targeting oncogenic miRNAs that enhance NF-κB signaling can also be a viable therapeutic approach. For example, inhibiting miR-362-5p could restore the expression of tumor suppressors that negatively regulate NF-κB, thereby reducing cancer cell proliferation and resistance to therapy [31]. Several miRNA-based therapeutics are currently in preclinical and clinical trials, with some showing promising results in reducing tumor burden and improving patient outcomes in BC [29, 30, 32–36].

Fig. 1.

Timeline illustrating key discoveries in miRNA-mediated regulation of the NF-κB signaling pathway (2006-2025): This timeline depicts the progressive understanding of how miRNAs modulate the NF-κB signaling cascade across different physiological and pathological contexts. Beginning with the 2006 discovery of NF-κB-dependent induction of miR-146a as a negative feedback regulator of innate immune signaling, subsequent milestones highlight the intricate interplay between miRNAs, inflammation, infection, and cancer. In 2007-2008, Epstein-Barr virus (EBV)-encoded LMP1 was shown to induce miR-146a and miR-155 through NF-κB activation, linking viral oncogenesis to immune modulation. Over the following decade, key findings revealed miRNA-NF-κB regulatory loops in neuro/chronic inflammation (miR-146a, miR-125b, miR-486), cancer (miR-221/222, miR-708, miR-196a, miR-155, miR-532), and immune signaling (miR-125a/b, miR-342). Recent studies (2020-2025) uncovered emerging roles of miRNAs in ferroptosis, pyroptosis, and extracellular vesicle-mediated intercellular communication, including miR-93-5p, miR-7-5p, miR-206-3p, and miR-146a/TAB 1 axis. Collectively, this timeline highlights the dual role of miRNAs in fine-tuning NF-κB activity, from immune regulation to cancer progression, and highlights their potential as therapeutic targets and biomarkers across diverse diseases

Therefore, this review summarizes various studies that have highlighted the significant roles of miRNAs in BC progression or suppression, suggesting their potential as promising therapeutic targets in BC treatment. It also provides an in-depth overview of both the canonical and non-canonical pathways of NF-κB signaling and its critical role in BC progression. The core aim of this review is to provide an in-depth analysis of recent advancements in miRNA-based therapies for the treatment of BC, which in turn results in making this treatment approach an integral part of personalized treatment strategies for BC patients.

NF-κB signaling: an overview

Cellular and developmental processes are tightly regulated by various signaling pathways [37–41]. Among these NF-κB pathway plays a pivotal role in the various developmental processes of tissues and organs [42, 43]. The NF-κB family includes TFs, such as RelA (p65), RelB, c-Rel, and the precursors NF-κB1 (p105) and NF-κB2 (p100) that process to p50 and p52, respectively [44, 45]. All these members share an identical N-terminal domain, the Rel homology domain (RHD), which enables DNA binding and dimerization. Except for RelB, which only forms heterodimers, NF-κB proteins can form both homo- and heterodimers [42, 46]. The NF-κB signaling cascade is regulated through two distinct mechanisms: the canonical (NEMO-dependent) and the non-canonical (NEMO-independent) pathways [46, 47]. The canonical pathway, which activates RelA, c-Rel, and NF-κB1, is triggered by receptors such as TNFR, TLRs, TCRs, and ILRs [42]. Activation of the IKK complex (IKKα, IKKβ, and NEMO) involves multiple mechanisms, including ubiquitination of NEMO and phosphorylation by TAK1 (Fig. 2) [46, 48–50]. The IKK complex phosphorylates the inhibitor IκB, leading to its ubiquitination and proteasomal degradation, thereby freeing NF-κB dimers for nuclear translocation [46, 51–54]. Upon nuclear translocation, NF-κB undergoes post-translational modifications and interacts with κB consensus sequences (5′-GGGRNWYYCC-3′) located within the promoter regions of its target genes [44, 54]. One of these targets, IκB, participates in a negative feedback loop that restores pathway homeostasis [44, 54].

Fig. 2.

Major receptor-mediated activation mechanisms of NF-κB signaling: Stimulation of TLR/IL-1R, TCR, and TNFR activates the canonical NF-κB pathway through the recruitment of adaptor proteins such as MyD88, TRADD, CARMA1, and TRAF family members, leading to activation of the TAK1-TAB complex and subsequent phosphorylation of the IKK complex (IKKα, IKKβ, and NEMO/IKKγ). This results in phosphorylation and degradation of IκBα, releasing the p50/p65 (RelA) heterodimer to translocate into the nucleus and induce transcription of NF-κB-responsive genes. In contrast, receptors such as RANK primarily activate the non-canonical NF-κB pathway, where stabilization of NIK leads to IKKα-mediated processing of p100 into p52, forming the p52/RelB transcriptional complex. Negative regulatory proteins, including A20, CYLD, and LUBAC, modulate both pathways to maintain signaling balance. The green balls represents the phosphorylation and the blue balls represents ubiquitination

The non-canonical NF-κB pathway is triggered by specific members of the TNF receptor superfamily, such as CD40, CD27, RANK, and the lymphotoxin β receptor, and is predominantly regulated by NF-κB-inducing kinase (NIK) [42, 55, 56]. NIK phosphorylates IKKα, which then phosphorylates p100, marking it for partial proteasomal degradation by β-TrCP to generate p52. The resulting p52/RelB heterodimer translocates to the nucleus and regulates transcription [46, 47, 55–57]. Only newly synthesized p100 is susceptible to this proteasomal processing [46, 58].

NF-κB in cancer

NF-κB is a central mediator of inflammation and immunity, activated by pro-inflammatory cytokines and regulating multiple chemokines and cytokines [56, 59–61]. It contributes to both innate and adaptive immune responses, making it vital for immune homeostasis [59, 62, 63]. Dysregulated or chronic NF-κB activation is implicated in inflammatory disorders such as psoriasis, inflammatory bowel disease (IBD), rheumatoid arthritis, and atherosclerosis, several of which are linked to cancer predisposition [64–75]. Chronic inflammatory states such as IBD or COPD can facilitate malignancies in the colon, skin, lymphatic system, and lungs, consistent with the concept of tumor-promoting inflammation as a hallmark of cancer [69–71, 76, 77]. Genetic alterations in NF-κB family genes have been detected in multiple cancers, particularly hematologic malignancies [78–80]. However, constitutive NF-κB activation in tumors often results not from mutation but from cytokine-driven microenvironmental signaling and aberrant upstream regulation [59, 81, 82]. This persistent activation promotes tumor cell survival, proliferation, and resistance to apoptosis, and cooperates with other oncogenic pathways, thereby contributing to malignant transformation [10, 59, 83].

NF-κB in breast cancer

Extensive studies have demonstrated a crucial role of NF-κB in the initiation and progression of BC. NF-κB is frequently overexpressed in inflammatory BC subtypes, while IKKε amplification sustains NF-κB activation in BC cells, and its inhibition triggers apoptosis [83, 84]. Similarly, IKKα supports the self-renewal of BC tumor-initiating cells and promotes metastasis through RANKL/RANK signaling driven by regulatory T cells [85, 86]. The CD40L/CD40/NF-κB axis contributes to neoplastic transformation [59, 87, 88].

NF-κB also interacts with oncogenic TFs and signaling cascades. It regulates FOXC1, a basal-like BC biomarker, via the EGF-NF-κB-FOXC1 axis, and cooperates with STAT3 in controlling genes linked to inflammation, cell cycle, and apoptosis [86, 89–91]. Crosstalk with HIF-1α promotes hypoxia-induced proliferation, migration, and epithelial-to-mesenchymal transition (EMT) [86, 92]. Collectively, NF-κB signaling underlies cancer cell survival, metastasis, and resistance to multiple BC therapies, including chemotherapy, radiotherapy, endocrine, and targeted therapies [86, 93]. These findings exhibit NF-κB’s role as a pivotal regulator of tumor progression and therapeutic resistance, making it an attractive target for developing innovative interventions in BC management.

MicroRNA

MiRNAs represent a class of small, endogenous RNA molecules, consisting of typically 19-24 nucleotides in size, that are evolutionarily conserved. Acting as post-transcriptional regulators of gene expression, miRNAs primarily modulate protein synthesis by base-pairing with complementary sequences within target mRNAs. This interaction interferes with translational processes, thereby controlling the expression of specific proteins [94]. In 1993, the discovery of the first miRNA, lin-4, was made by the Ambros and Ruvkun groups in Caenorhabditis elegans [95–97]. MiRNAs are predominantly transcribed into the primary miRNAs (pri-miRNAs) from the DNA sequences. These pri-miRNAs undergo sequential enzymatic processing to generate precursor miRNAs (pre-miRNAs), which are then further processed into biologically active mature miRNAs. Mature miRNAs typically regulate gene expression by binding to complementary sequences within the 3′ untranslated region (UTR) of target mRNAs, resulting in the suppression of gene expression [98]. However, interactions with other regions like the 5′ UTR, gene promoters, and coding sequences have also been observed [95, 99]. Studies also suggest that miRNAs can be shuttled across various subcellular compartments to modulate translation and even transcription rates [95, 100].

Biogenesis of MiRNA

MiRNA biogenesis is an intricate, multi-level process that begins with the transcription of RNA by the polymerase II/III transcripts in the nucleus and culminates in the production of mature miRNA in the cytoplasm. This process can be classified into two pathways: canonical and non-canonical (Fig. 3) [95, 98, 101].

Fig. 3.

Canonical and non-canonical pathways of miRNA biogenesis: This schematic illustrates the two main routes of miRNA biogenesis: the canonical and non-canonical pathways. In the canonical pathway, miRNA genes are transcribed by Pol II into pri-miRNA transcripts within the nucleus. The Microprocessor complex, composed of DROSHA and DGCR8, cleaves pri-miRNA into pre-miRNA. The pre-miRNA is then exported to the cytoplasm via Exportin-5 in a Ran-GTP-dependent manner. In the cytoplasm, DICER, along with its cofactor TRBP, further processes the pre-miRNA into a mature double-stranded miRNA duplex. One strand (the guide strand) is incorporated into the RISC containing AGO2, leading to target mRNA recognition and gene silencing or degradation. In contrast, the non-canonical pathway bypasses either DROSHA or DICER processing. For example, mirtrons, which originate from spliced introns, are processed by the spliceosome and debranching enzymes to generate pre-miRNAs that enter the cytoplasmic phase directly. Overall, both pathways converge on the formation of functional miRNAs that regulate gene expression posttranscriptionally

Canonical

It is the predominant signaling pathway by which the miRNAs are processed. Here, the pri-miRNA, transcribed by RNA polymerase II, undergoes cleavage in the nucleus by the microprocessor complex composed of Drosha and DGCR8. The resulting pre-miRNA is then transported to the cytoplasm by exportin-5 [102]. In the cytoplasm, Dicer enzymatically cleaves the terminal loop of pre-miRNA, producing a double-stranded miRNA duplex. The resulting miRNA duplex is subsequently incorporated into an Argonaute protein. After the passenger strand is removed, the remaining single-stranded mature miRNA guides the Argonaute-bound RNA-induced silencing complex (RISC) to recognize and suppress complementary target RNAs [102].

Non-canonical

Several alternative, non-canonical miRNA biogenesis pathways have been identified, each utilizing distinct combinations of proteins commonly associated with the canonical pathway, including Argonaute, Drosha, Dicer, and Exportin-5 [95]. Here, the formation of miRNA involves the generation of pre-miRNAs unaided by the microprocessor complex. A mechanism that circumvents the microprocessor is the generation of mirtrons, which are pre-miRNA analogs produced through the action of the spliceosome and intron-debranching enzymes. Furthermore, RNase Z-mediated tRNA synthesis can produce useful pre-miRNAs in the case of the murine hepatitis virus [102]. Another non-canonical pathway involves the transcription of pre-miRNAs with a 7-methylguanosine (m⁷G) cap directly by RNA polymerase II, which are subsequently transported to the cytoplasm via Exportin-1. Since Argonaute loading necessitates a 5′-monophosphate end, Dicer-mediated cleavage of these capped pre-miRNA hairpins predominantly generates mature miRNAs primarily from the 3’ arms [102].

MiRNA in cancer

MiRNAs are increasingly recognized as a promising cancer biomarker due to several key attributes. Firstly, miRNA molecules are easily accessible for study as they are abundantly present in various body fluids. Additionally, their remarkable biological stability enhances their reliability for detection. Further, miRNAs play critical roles in regulating chronic diseases and multiple stages of tumor development and often exhibit tissue-specific expression patterns [103–105]. With respect to cancer, miRNAs play a critical role in cell transformation [106]. They can function either as tumor suppressor genes or oncogenes, depending on the targets they regulate. This dual role suggests their importance in cancer biology and their potential utility in cancer diagnosis and therapy [106, 107].

Molecular interplay between MiRNAs and NF-κB signaling in breast cancer

Studies have demonstrated that miRNAs, functioning either as oncomiRs or TS-miRs, modulate various signaling pathways, including NF-κB, leading to significant anticancer effects in BC (Fig. 4) [108–111]. The following section provides an in-depth exploration of how these miRNAs exert their influence on BC by modulating the NF-κB signaling pathway, highlighting their critical roles in cancer progression and potential therapeutic applications (Fig. 5) (Tables 1 and 2).

Fig. 4.

MiRNAs involved in breast cancer (BC). OncomiRs promote tumor progression by enhancing angiogenesis, invasion, proliferation, and migration, whereas TS-miRs inhibit these tumorigenic pathways and induce apoptosis. The figure illustrates key miRNAs functioning as oncogenic (red) or tumor-suppressive (green) regulators across major cancer hallmarks, highlighting their dual roles in BC development and progression

Fig. 5.

miRNA-mediated modulation of NF-κB signaling in breast cancer: This schematic illustrates the regulatory roles of miRNAs in modulating both the canonical and non-canonical NF-κB signaling pathways, which are critical in controlling cell proliferation, survival, apoptosis, and inflammatory responses in breast cancer. In the canonical pathway, activation of receptors such as TLR, TNFR1, and IL-1R initiates downstream signaling that activates the IKK complex (IKKα, IKKβ, and NEMO), leading to IκBα phosphorylation and degradation. This releases NF-κB dimers (p50/p65/c-Rel), which translocate to the nucleus to induce transcription of pro-inflammatory cytokines, chemokines, and survival genes. Dysregulated miRNAs, including miR-29a, miR-138, miR-423, miR-187, miR-562, miR-362-5p, miR-892b, miR-200b, miR-222, miR-370-3p, miR-187, miR-222, miR-322, miR-26b, miR-373, miR-520 etc., influence these steps by targeting IKK components or IκBα, thereby altering NF-κB activation and its transcriptional output. The non-canonical pathway, activated by TNF, RANK, CD27, and CD40, involves the TRAF2/TRAF3/NIK/IKKα axis, culminating in p100 processing to p52 and nuclear translocation of p52/RelB dimers. miRNAs such as miR-29b-3p, miR-370-3p, miR-301b, miR-892b-3p, miR-1910-3p, miR-188-5p, etc., modulate this pathway by targeting TRAF3, NIK, or RelB, thereby influencing tumor cell survival and apoptosis. Collectively, the interplay between miRNAs and NF-κB signaling orchestrates a complex regulatory network that determines the inflammatory and oncogenic balance in breast cancer, highlighting miRNAs as potential biomarkers and therapeutic targets

Table 1.

MiRNA expression in breast cancer

miRNA	In silico/In vitro/ In vivo/Clinical	Model used	Expression	Reference
miR-29b-3p	In vitro	MDA-MB-231 cells	Up	[112]
miR-423	In silico	Human breast cancer tissues	Up	[108]
	In vitro	MDA-MB-468, T47D, Bcap37, SK-BR3, MCF-7, MDA-MB-231 cells
miR-892b	In vitro	ZR-75-30, ZR-75-1, MCF-7, BT549, BT474, SK-BR3, MDA-MB-415, MDA-MB-435, MDA-MB-468, MDA-MB-231, MDA-MB-435 cells	Down	[110]
miR-370	In silico	Breast cancer samples	Up	[111]
miR-222	Clinical	Breast cancer patients	Up	[113]
miR-1910-3p	In vitro	MDA-MB-231, MCF-7 cells	Up	[114]
miR-1910-3p	Clinical	Breast cancer tissues	Up	[114]
miR-217-5p	In vitro	MCF-7, BT549, SKBR3 cells	Down	[115]
miR-217-5p	Clinical	Breast cancer tissues	Down	[115]
miR-370-3p	In vitro	MCF-7, MDA-MB-231 cells	Up	[116]
miR-370-3p	Clinical	Breast cancer tissues	Up	[116]
miR-449a	In silico	Lymph node-negative invasive ductal breast cancer samples	Up	[33]
miR-449a	In vitro	MDA-MB-231, T47D, MDA-MB-453 cells	Up	[33]
miR-449a	Clinical	Lymph node-negative invasive ductal breast cancer samples	Up	[33]
miR-502-5p	Clinical	Breast cancer tissues	Down	[34]
miR-502-5p	In vitro	MCF-7, MDA-MB-231 cells	Down	[34]
miR-7	Clinical	Breast cancer tissues	Down	[117]
miR-310b	Clinical	Breast cancer tissues	Up	[35]
miR-310b	In vitro	BT-549, MDA-MB-231, MDA-MB-468, HCC1937, MDA-MB-436 cells	Up	[35]
miR-29a	In vitro	MCF-7, MDA-MB-231, T47D cells	Down	[118]
miR-29a	Clinical	Breast cancer tissues	Down
miR-362-5p	In vitro	MDA-MB-231, MCF-7 cells	Up	[31]
miR-188-5p	In vitro	MDA-MB-231, BT-549, MCF-7 cells	Down	[119]
miR-188-5p	Clinical	Breast cancer tissues	Down
miR-187	In vitro	MCF-7, MDA-MB-231, MDA-MB- 453, MDA-MB-468 cells	Up	[120]
miR-26b*	In vitro	MDA-MB-231 cells	Down	[121]
miR-562	In vitro	MDA-MB-231 cells	Down	[121]
miR-185-5p	In vitro	MCF-7, T47D, MDA-MB-231, MDA-MB-453, SK-BR-3 cells	Down	[122]
miR-6767-5p	In vitro	MCF-7, MDA-MB-231, SK-BR3, T47D cells	Up	[123]
Exosomal miR-105-5p	In vitro	Exo-MDA-MB-231	Up	[124]

Table 2.

Various OncomiRs modulating NF-κB signaling in breast cancer

miRNA	In silico/ In vitro/ In vivo/ Clinical	Model used	Target	Effect on NF-κB/its associated proteins	Mechanism/Outcome	Reference
miR-29b-3pA	In vitro	MDA-MB-231 cells	TRAF3	↑NF-κB, p-NF-κB, IκB-α, p-IκB-α	↑Colony formation, migration, invasion; ↓cleaved PARP	[112]
miR-29b-3pB	In vitro	MDA-MB-231 cells	TRAF3	↓NF-κB, p-NF-κB, IκB-α, p-IκB-α	↑Apoptosis, nuclear fragmentation, cell blebbing, cytoskeleton damage, cleaved PARP; ↓Proliferation, colony formation, migration, invasion	[112]
miR-423A	In vitro	MCF-7 and SK-BR3 cells	TNIP2	↑NF-κB transcriptional activity	↑Migration, invasion, Snail1, Twist1	[108]
miR-423B	In vitro	MDA-MB-231	TNIP2	-	↓Invasion	[108]
EVs from MDA-MB-231/MDA-MB-436	In vitro	Normal fibroblasts from BC patients	-	↑NF-κB p65/NF-κB	-	[111]
EVs from MDA-MB-231 transfected with miR-370-3pA	In vitro	Normal fibroblasts from BC patients	-	-	↑Migration, invasion, IL-1β, IL-6, IL-8	[111]
EVs from MDA-MB-231/MDA-MB-436 transfected with miR-370-3pB	In vitro	Normal fibroblasts from BC patients	-	-	↓Migration, invasion, IL-1β, IL-6, IL-8	[111]
miR-222A	In vitro	MCF-7 cells	PDLIM2	↑RelA, RelB; ↓PDLIM2	↑Migration, invasion	[113]
miR-222B	In vitro	MDA-MB-231 cells	PDLIM2	↑PDLIM2; ↓RelA, RelB	↓Invasion, migration	[113]
miR-222A	In vivo	Mice model (MCF-7 xenograft)	PDLIM2	↑RelA, RelB; ↓PDLIM2	↑Tumor formation rate, tumor weight, tumor volume	[113]
miR-1910-3pA	In vitro	MDA-MB-231 and MCF-7 cells	MTMR3	↑p-p65; ↓p-IκBα, MTMR3	↑Migration, colony formation, N-cadherin, Vimentin, Slug, Twist, Bcl2, PCNA, ATG7, BECN1, LC3B, Wnt2, Wnt3, Wnt5, Wnt10b, β-catenin; ↓E-cadherin, cleaved Caspase 3, PARP, apoptosis	[114]
miR-1910-3pA	In vivo	Mice model (MDA-MB-231 xenograft)	MTMR3	↑p-p65; ↓p-IκBα, MTMR3	↑Tumor volume, tumor weight, N-cadherin, Vimentin, PCNA, β-catenin; ↓E-cadherin	[114]
miR-1910-3pB	In vitro	MDA-MB-231 and MCF-7 cells	MTMR3	↑p-IκBα, MTMR3; ↓p-p65	↑E-cadherin, cleaved Caspase 3, PARP, apoptosis; ↓Migration, colony formation, N-cadherin, Vimentin, Slug, Twist, Bcl2, PCNA, ATG7, BECN1, LC3B, Wnt2, Wnt3, Wnt5, Wnt10b, β-catenin	[114]
miR-1910-3pB	In vivo	Mice model (MDA-MB-231 xenograft)	MTMR3	↑p-IκBα, MTMR3; ↓p-p65	↑E-cadherin; ↓Tumor volume, tumor weight, N-cadherin, Vimentin, PCNA, β-catenin	[114]
miR-370-3pA	In vitro	MCF-7 and MDA-MB-231 cells	FBLN5	↑NF-κB-p65	↑Migration, proliferation, N-cadherin, Vimentin, PCNA, OCT4, SOX2; ↓E-cadherin	[116]
miR-370-3pA	In vivo	Mice model (MDA-MB-231 xenograft)	FBLN5	-	↑Tumor weight, N-cadherin, Vimentin; ↓E-cadherin	[116]
miR-370-3pB	In vitro	MCF-7 and MDA-MB-231 cells	FBLN5	↓NF-κB-p65	↑E-cadherin; ↓Migration, proliferation, N-cadherin, Vimentin, PCNA, OCT4, SOX2	[116]
miR-370-3pB	In vivo	Mice model (MDA-MB-231 xenograft)	-	-	↑E-cadherin; ↓Tumor weight, N-cadherin, Vimentin	[116]
miR-668A	In vitro	MCF-7 and T47D cells	IκBα	↑p65, NF-κB binding activity; ↓IκBα	↑Survival fraction	[125]
miR-668B	In vitro	MCF-7R and T47DR cells (Radioresistant)	IκBα	↑IκBα; ↓p65, NF-κB binding activity	↓Survival fraction	[125]
miR-449aB	In vitro	T47D cells	CRIP2	↓NF-κB target gene (VEGF)	↓Cell viability, colony formation	[33]
miR-449aB	In vitro	MDA-MB-231 cells	CRIP2	↓NF-κB target gene (VEGF)	↓Cell viability, colony formation, migration, invasion	[33]
miR-187A	In vitro	MCF-7 and MDA-MB-231 cells	HIPK3	↑p65, p50	↑Cell viability, invasion; ↓HIPK3	[120]
miR-362-5pB	In vitro	MCF-7 cells	CYLD	↑Cytoplasmic p-65 ↓Nuclear p-65	↑G1 phase arrest, apoptosis, CYLD; ↓Proliferation, colony formation, migration, invasion	[31]
miR-301bB	In vitro	MDA-MB-231 and HCC1937 cells	CYLD	↓p-p65	↑Apoptosis induced by 5-FU, CYLD; ↓Cell viability, colony formation, IL-8, Bcl-2, XIAP	[35]
miR-301bA	In vitro	MDA-MB-231 and HCC1937 cells	CYLD	↑p-p65	↑Cell viability, colony formation, p-p65, IL-8, Bcl-2, XIAP; ↓Apoptosis induced by 5-FU, CYLD	[35]
miR-6767-5pB	In vitro	MDA-MB-231 and MCF-7 cells	CRIP2	↓p-p65	↑CRIP2, E-cadherin; ↓Proliferation, migration, invasion, N-cadherin, Vimentin, % of S phase cells	[123]
miR-6767-5pB	In vivo	Mice- lung metastasis model (MDA-MB-231 cells xenograft)	-	-	↓Tumor growth	[123]
miR-6767-5pB	In vivo	Mice model (MCF-7 cells xenograft)	-	-	↓Tumor growth	[123]
miR-6767-5pA	In vitro	MDA-MB-231 and MCF-7 cells	CRIP2	-	↑Proliferation, invasion, migration, % of S phase cells	[123]
Exosomal miR-3960A	In vitro	MDA-MB-231 cells	BRSK2	-	↑Cisplatin resistance	[126]
Exosomal miR-105-5pA	In vitro	Normal fibroblasts from breast cancer patients	LATS2	↑p-p65; ↓IκBα	↑FAP, migration ⍺-SMA, IL-1𝛽, IL-6, IL-8; ↓LATS2	[124]
Exosomal miR-105-5pA	In vivo	Mice model (MDA-MB-231/Normal fibroblast mixtures xenograft)	-	-	↑Number of metastatic nodules, FAP, ⍺-SMA	[124]

^AOverexpressed;^BKnockdown

Table 3.

Various TS-miRs modulating NF-κB signaling in breast cancer

miRNA	In silico/ In vitro/ In vivo/ Clinical	Model used	Target	Effect on NF-κB/its associated proteins	Mechanism/Outcome	Reference
miR-138A	In vitro	MCF-7 cells	-	↓NF-κB	↑Apoptosis rate, caspase-3, -9; ↓Cell proliferation, IL-1β, IL-6, IL-18, TNF-α, Bax, VEGF	[109]
miR-892bA	In vitro	MDA-MB-231 and ZR-75-30 cells	TRAF2, TAB 3, TAK1	↑Cytoplasmic NF-κB; ↓NF-κB transcriptional activity, TRAF2, TAB 3, TAK1, p-IKK-β, K63-polyubiquitin levels of RIP1	↓Colony formation, anchorage-independent growth, invasion, angiogenesis	[110]
miR-892bA	In vivo	Mice model (MDA-MB-231 miR-829b OE xenograft)	-	↓NF-κB p65, VEGFC, MMP-9, CD31	↑Survival; ↓Tumor size, tumor weight, proliferation, microvascular density, metastasis	[110]
miR-892bB	In vitro	MDA-MB-231 and ZR-75-30	TRAF2, TAB 3, TAK1	↑Nuclear NF-κB, NF-κB transcriptional activity, TRAF2, TAB 3, TAK1, p-IKK-β, K63-polyubiquitin levels of RIP1	↑Colony formation, anchorage-independent growth, invasion,angiogenesis	[110]
miR-892bB	In vivo	Mice model (MDA-MB-231 miR-829b silenced xenograft)	-	↑NF-κB p65, nuclear localization of NF-κB p65, VEGFC, MMP-9, CD31	↑Tumor size, tumor weight, proliferation, microvascular density, metastasis, MMP-9, VEGFC; ↓Survival	[110]
miR-217-5pA	In vitro	SK-BR3 cells	MTDH	↑IκBα; ↓p-p65	↑E-cadherin; ↓Proliferation, colony formation, migration, invasion, Vimentin, Slug	[115]
miR-217-5pB	In vitro	SK-BR3 cells	MTDH	↑p-p65; ↓IκBα	↑Cell proliferation, colony formation, migration, invasion, Vimentin, Slug; ↓E-cadherin	[115]
miR-30c‐2‐3pA	In vitro	MDA-MB-231 cells (TNF-α-induced)	TRADD, CCNE1	↓IL-6, IL-8, CXCL1. p-p105	↑Apoptosis; ↓Myc, CCND1, CSF2, cell viability, MMP-9, cell cycle progression, invasion	[127]
miR-188-5pA	In vitro	MDA-MB-231 cells	ZFP91	↓NF-κB, RELB, ZFP91	↑Apoptosis ratio, Vimentin, N-cadherin ↓Cell proliferation, migration, invasion, E-cadherin, colony formation, MMP-2, -9	[119]
miR-188-5pA	In vivo	Mice model (MDA-MB-231 xenograft)	ZFP91	-	↓Tumor weight, tumor volume	[119]
miR-184A	In vitro	MCF-7 cells	-	↓Relative NF-κB activity	↑p53, p21, caspase-3,-8, G0/G1 phase arrest; ↓Cell viability, relative adhesion rate, invasion, MMP-2,-9, CD44, p-AKT, SND1	[128]
miR-7A	In vitro	MDA-MB-231, MCF-7 and SK-BR3 cells	RELA	↓RELA	↓CD44	[117]
miR-7A	In vitro	MDA-MB-231 cells	RELA, XIST	↓RELA	↑miR-92b; ↓CD44, ESA	[117]
miR-7 A	In vivo	Mice model (MDA-MB-231 xenograft)	RELA	↓RELA	↓Tumor size, CD44, Slug, ESA	[117]
miR-7B	In vitro	MDA-MB-231, MCF-7 and SK-BR3 cells	RELA	↑RELA	↑CD44	[117]
miR-146aA	In vitro	MDA-MB-231 cells	-	↓p-IκBα, IRAK1, TRAF6	↓IL-8, IL-6, MMP-9, invasion, migration	[129]
miR-146bA	In vitro	MDA-MB-231 cells	-	↓p-IκBα, IRAK1, TRAF6	↓IL-8, IL-6, MMP-9, invasion, migration	[129]
miR-502-5pA	In vitro	MCF-7 and MDA-MB-231 cells	TRAF2	↓TRAF2	↑Apoptosis; ↓Cell proliferation, colony formation	[34]
MiR-502-5pB	In vitro	MCF-7 and MDA-MB-231 cells	-	-	↑Cell proliferation, colony formation	[34]
miR-185-5pA	In vitro	MDA-MB-231 cells	RAGE	↓p-IκBα, IκBα	↑E-cadherin; ↓RAGE, invasion, Vimentin	[122]
miR-185-5pA	In vivo	Mice model (MDA-MB-231 xenograft)	RAGE	-	↑Vimentin; ↓RAGE, no: of tumor nodule	[122]
miR-200bA	In vitro	SK-BR3 and T47D cells	IKBKB	↓IKBKB, p-IκBα, nuclear p50, nuclear p65, NF-κB	↓Cell growth, colony formation, migration	[130]
miR-31A	In vitro	MDA-MB-231 cells	Protein kinase Cε	↓NF-κB activity	↑Apoptosis; ↓Bcl-2	[36]
miR-562A	In vitro	MCF-7 cells	NF-κB1	↑p50; ↓NF-κB, NF-κB1, p105	↑Endothelial cell angiogenesis; ↓Migration	[121]
miR-26b*A	In vitro	MCF-7 cells	RELA	↓NF-κB, RELA, p65	↑Endothelial cell angiogenesis	[121]
miR-373A	In vitro	MDA-MB-231 cells	TGFBR2	↓RELA, IL-6, -8, CXCL1, ICAM-1	↓Cell invasion, LCAM intravastion	[131]
miR-520cA	In vitro	MDA-MB-231 cells	TGFBR2	↓RELA, IL-6, -8, CXCL1, ICAM-1	↓Cell invasion, LCAM intravasation	[131]
miR-520cB	In vitro	MDA-MB-231 cells	-	↑TGFBR2	↑Cell invasion	[131]
miR-29aA	In vitro	MCF-7 cells	TNFR1	↓NF-κBp65	↑Cells in the G0/G1 phase, apoptosis, Bax; ↓TNFR1, cell proliferation, colony formation, Bcl-2, Cyclin D1	[118]
miR-140-5pA	In vitro	MDA-MB-231 cells	-	↓p-p65, NF-κB	G0/G1 phase cell cycle arrest; ↑Cell adhesion rate, E-cadherin; ↓Cell viability, colony formation, invasion, migration, CDK2, p-AKT, p-STAT-3	[132]
miR-140-5pA	In vivo	Mice model (MDA-MB-231 xenograft)	-	-	↑E-cadherin; ↓Tumor volume, CDK2, p-AKT, p-STAT3	[132]

^AOverexpressed;^BKnockdown

OncomiRs

OncomiRs are miRNAs that are overexpressed in tumors and contribute to tumorigenesis by downregulating tumor suppressor proteins (Table 2). For instance, Zhang et al. demonstrated that miR-29b-3p acts as an oncomiR in MDA-MB-231 BC cells by targeting the 3’-UTR of TRAF3, thereby inducing the activation of the NF-κB signaling cascade [112]. However, treatment with the miR-29b-3p inhibitor led to a decrease in cell viability and impeded their migratory and invasive capabilities. Additionally, it resulted in damage to the cell cytoskeleton and destroyed the structural integrity of the cell [112]. Another study reported that miR-423 has elevated expression in human BC tissues relative to normal tissues using TCGA data [108]. The ectopic expression of miR-423 in BC cells led to increased invasiveness by promoting activation of the NF-κB signaling axis and upregulating the levels of Snail and Twist proteins. Conversely, the inhibition of miR-423 suppressed this pathway. Moreover, TNIP2 has been identified as a target gene of miR-423, and the suppression of TNIP2 was linked to increased invasiveness, suggesting that miR-423 could be used as a promising prognostic and therapeutic marker for the management of metastatic BC [108]. Another study showed that extracellular vesicles (EV) derived from BC cells facilitate the transfer of miR-370-3p, which exacerbates BC progression through fibroblast activation [111]. This effect was mediated by the downregulation of CYLD and activation of the NF-κB signaling cascade in the fibroblasts [111]. In another study, Ding et al. revealed that the levels of exosomal miR-222 have been correlated with the metastatic progression of advanced BC [113]. The transfer of miR-222 via exosomes augmented the migratory and invasive abilities of BC cells. Further, miR-222 contributed to the tumorigenicity of these cells by downregulating PDLIM2 and thereby inducing NF-κB signaling [113]. Another study demonstrated that overexpression of miR-1910-3p resulted in enhanced proliferative and migratory capacities, inhibition of apoptosis, and induction of autophagy in MDA-MB-231 and MCF-7 cells [114]. Similarly, in vivo studies also confirmed that miR-1910-3p promoted the proliferative and migratory potential of BC xenograft models. Mechanistically, miR-1910-3p was found to downregulate myotubularin-related protein 3 (MTMR3) and activate the NF-κB and Wnt/β-catenin signaling pathways, implicating a crucial role of miR-1910-3p in the management of BC [114].

Another in vitro study revealed that miR-370-3p, which is upregulated in BC patients, suppressed FBLN5 expression and promoted NF-κB signaling pathway activation, thereby facilitating the progression of the disease [116]. Additionally, in vivo experiments have also shown that miR-370-3p enhances tumour growth and promotes the expression of EMT-associated proteins [116]. Shi et al. reported that miR-449a suppressed cysteine-rich protein 2 (CRIP2) expression, which subsequently increased clonogenicity, cell survival, migration, and invasion, and activated pro-angiogenic protein, VEGF, potentially via the NF-κB/p65 complex, in preclinical settings [33]. Another in vitro study demonstrated that miRNA-301b targets CYLD and activates NF-κB, resulting in cell proliferation and apoptosis resistance in MDA-MB-231 and HCC1937 cells, suggesting its oncogenic role and indicating how its modulation could result in a novel therapeutic approach for the management of TNBC [35]. Another study showed that inhibition of miR-362-5p expression using a miR-362-5p inhibitor led to the upregulation of CYLD protein expression and a reduction in nuclear NF-κB expression in MCF-7 cells [31]. This suppression ultimately resulted in decreased proliferation, invasion, and migration of this BC cells [31]. Hu et al. reported that miR-187 downregulated the expression of HIPK3, while upregulating the expression of p65 and p50 in BC cells. These changes were associated with increased cell viability and enhanced invasiveness in vitro [120]. An in vitro study demonstrated that miR-668 enhanced the radioresistance of human BC cells MCF-7 and T47D by targeting IκBα [125]. Ding X et al. demonstrated that exosomal miR-105-5p derived from BC cells facilitated the transformation of normal fibroblasts (NFs) into cancer-associated fibroblasts (CAFs) by directly targeting and downregulating LATS2, leading to the activation of the NF-κB signaling pathway. These CAFs concurrently promoted EMT in BC cells, suggesting that exosomal miR-105-5p represents a promising therapeutic target to disrupt the reciprocal crosstalk and coevolution between BC cells and CAFs [124]. Tan and colleagues demonstrated that miR-6767-5p acts as an oncogenic miRNA in BC, enhancing cell proliferation, migration, and invasion in preclinical settings. miR-6767-5p directly targets and suppresses CRIP2, resulting in NF-κB activation and induction of EMT. Upstream, the study identified SP1 transcriptionally upregulates miR-6767-5p, and this process is driven by MAP2K4 through the PI3K/Akt/c-Jun/SP1 signaling axis. Clinically, high expression of miR-6767-5p correlated with advanced tumor stage and poor prognosis in BC patients, highlighting its potential as both a prognostic biomarker and a therapeutic target [123]. Another study reported that SOD1-high fibroblast-derived exosomal miR-3960 enhanced cisplatin resistance in MDA-MB-231 TNBC cells by suppressing BRSK2, which regulates the stability of PIMREG and supresses NF-κB signaling [126]. Such miRNA-NF-κB crosstalk reveals novel therapeutic avenues for overcoming drug resistance and tumor progression. Overall, these studies suggest that modulating these oncomiRs presents a potential alternative strategy for the management of BC.

Tumor suppressor MiRs

TS-miRs exhibit downregulation in numerous cancers and function as tumor suppressors. They exert their tumoricidal activities by specifically targeting oncogenic mRNAs, thereby inhibiting tumor development and progression (Table 2). For example, the upregulation of miR-892b in BC cells resulted in the suppression of the NF-κB signaling pathway through downregulating TRAF2, TAB 3, and TAK1, thereby reducing tumor growth, metastatic potential, and angiogenesis in preclinical settings [110]. In another study, Yang et al. revealed that the overexpression of miR-217-5p led to the inhibition of metadherin (MTDH) and NF-κB signaling pathway [115]. This inhibition subsequently resulted in decreased cell proliferation, colony formation, invasion, and migration while also suppressing the EMT in vitro [115].

Another study revealed that miR-502 is expressed at lower levels in BC relative to normal tissues. Ectopic expression of miR-502 in BC cell lines MCF-7 and MDA-MB-231 using a miR-502 mimic led to downregulation of TRAF2 expression and exhibited anticancer effects, such as increased apoptosis, reduced proliferation, and diminished colony formation of these cells [34]. An intriguing study reported that the overexpression of miR-7 resulted in the inhibition of XIST and a decrease in epithelium-specific antigen (ESA) expression by upregulating miR-92b and inhibiting Slug. Additionally, miR-7 concurrently suppressed CD44 by targeting and inhibiting RELA and Slug in preclinical settings [117]. Zhao et al. demonstrated that miR-29a targets TNFR1, leading to the inactivation of the NF-κB signaling pathway and suppressing MCF-7 cell growth [118]. Another study demonstrated that miR-188-5p targets zinc finger protein 91 (ZFP91), inhibiting NF-κB-p65, which resulted in the induction of apoptosis, reduced colony formation ability, invasion, and migration, and the suppression of EMT in TNBC cells. Similar effects on ZFP91 expression and tumor growth were observed in vivo [119]. Further, miR-26b* and miR-562 led to the downregulation of NF-κB activity levels. This modulation may contribute to increased endothelial cell tube formation and reduced wound healing ability in BC cells [121]. Furthermore, miR-185-5p inhibited F-actin polymerization, thereby affecting the chemotaxis ability of cells and reversing EMT through the NF-κB pathway while modulating the receptor for advanced glycation end products (RAGE) in preclinical models [122]. In another study, overexpression of miR-138 led to a decrease in NF-κB and VEGF expression, lowered the levels of inflammatory cytokines, including IL-6, IL-18, IL-1β, and TNF-α, and reduced proliferation, while inducing apoptosis in MCF-7 cells [109]. Shukla et al. reported that TRADD and CCNE1 are targets of miR-30c-2-3p [127]. Overexpression of miR-30c-2-3p in TNF-α-stimulated MDA-MB-231 cells led to a reduction in NF-κB signaling activation. Moreover, miR-30c-2-3p also reduced proinflammatory cytokines, such as IL-8, IL-6, and CXCL1, as well as downregulated NF-κB transcriptional targets such as MYC, CCND1, and CSF2. Ultimately, overexpression of this miRNA led to a reduction in cell viability and induction of apoptosis in vitro [127].

Another study demonstrated that overexpression of miR-146a/b in MDA-MB-231 cells reduced the phosphorylation of IκBα and decreased NF-κB DNA-binding activity. This resulted in the downregulation of IL-8, IL-6, and MMP-9 expression. Additionally, miR-146a/b overexpression led to a reduction in the invasion and migration capabilities of these cells [129]. Hou et al. demonstrated that the upregulation of miR-140-5p resulted in the downregulation of CDK2 and AKT/STAT3/NF-κB signaling pathway-related proteins. This led to cell cycle arrest, decreased cell proliferation, suppressed invasion and migration, enhanced cell adhesion, and increased E-cadherin expression in pre-clinical settings [132]. Additionally, miR-184 overexpression in MCF-7 BC cells was also shown to enhance cell adhesion by upregulating the expression of p53 and p21, as well as caspase-3 and caspase-8 activity. Also, miR-184 suppressed the expression of staphylococcal nuclease and tudor domain containing 1 (SND1), MMP-2, MMP-9, CD44, and AKT/NF-κB pathway activity [128]. Another study reported that the miRNA-520/373 family targets signaling pathways like the TGF-β and NF-κB and acts as a tumor suppressor by demonstrating various anticancer activities, such as inhibition of invasion, reduction of cytokine expressions such as IL-6 and IL-8 in vitro, and suppression of vascular intravasation in vivo [131]. An intriguing study revealed that overexpression of miR-31 led to inhibition of NF-κB activity, a decrease in Bcl-2 expression, and induced apoptosis in the TNBC cell line MDA-MB-231 [36]. An in vitro study demonstrated that miR-200b overexpression led to the attenuation of cell growth, migration, and NF-κB activation by inhibiting inhibitor of nuclear factor kappa B kinase subunit beta (IKBKB) expression [130]. Collectively, these studies highlight the role of TS-miRs in BC. They demonstrate how these TS-miRs can be modulated to inhibit key oncogenic pathways, suggesting their potential as an alternative therapeutic strategy for BC treatment.

MiRNA delivery: strategies, advances, and translational potential

Efficient and targeted delivery of miRNA therapeutics remains a major challenge in translating preclinical discoveries into clinical success. Delivery strategies are designed to ensure selective targeting of tumor cells while minimizing off-target effects and degradation. Among these, viral vector-based systems are among the earliest and most effective delivery approaches. Genetically modified viral vectors, such as retroviral, lentiviral, adeno-associated virus (AAV), and bacteriophage-derived virus-like particles (VLPs), have demonstrated high transduction efficiency, stable gene expression, and the ability to transduce both dividing and non-dividing cells. These vectors are engineered to remove pathogenic sequences, thereby reducing toxicity and enhancing biosafety [133]. Despite their advantages, viral delivery systems carry limitations, including the risk of insertional mutagenesis, limited packaging capacity, immunogenicity, and production complexity [133].

To overcome these barriers, non-viral delivery platforms, particularly nanoparticle-based systems, have emerged as promising alternatives. Lipid-, polymeric-, and inorganic nanoparticles enable efficient encapsulation and delivery of miRNAs while offering scalability, biocompatibility, and tunable surface properties for enhanced cellular uptake [134].

Examples include gold nanoparticles (NPs), gold-iron oxide NPs, silica NPs, and silicon dioxide NPs, which have been explored for miRNA delivery in human systems [135]. An interesting study showed the use of an RNA-based NP delivery system to target stem cell marker CD133 in TNBC [136]. Another study reported that gold NP-based delivery of a miR-708 mimetic effectively reduced BC metastasis in preclinical models [137]. Hayward et al. revealed the therapeutic potential of miR-125a-5p as a standalone treatment for HER2-positive metastatic BC through targeted delivery using engineered lipid NP, suggesting it as a promising nonviral, translational delivery platform [138]. Beyond synthetic systems, EVs, particularly exosomes, have gained attention as naturally derived, nanoscale delivery carriers. EVs facilitate intercellular communication and possess inherent stability, safety, and targeting capabilities, making them ideal for therapeutic miRNA transport [139, 140]. Additional delivery innovations include N-acetylgalactosamine (GalNAc)-based conjugates, which enhance tissue-specific delivery, and 3D scaffold-based systems such as hydrogels and electrospun fibers that enable sustained, localized miRNA release [139]. Furthermore, ultrasound-targeted microbubble destruction has emerged as a non-invasive approach to enhance tissue penetration and therapeutic efficacy, as demonstrated by the successful delivery of miR-133a, which inhibited tumor growth and improved survival in vivo [141]. Recent advancements in nanoparticle engineering have further strengthened the translational potential of miRNA therapeutics. Gareev et al. highlighted both viral and non-viral vectors, including lipid, polymeric, peptide, inorganic, and exosome-based carriers, that improve miRNA stability, bioavailability, and tumor-specific accumulation [142]. Importantly, Farhana et al. demonstrated that gold NPs can restore TS-miRs activity, specifically, gold NP-mediated upregulation of miR-26a-5p effectively suppressed IL-6 expression and NF-κB (RelA/p50) signaling in BC cells [143].

Collectively, these advancements highlight the translational promise of nanocarrier-based, spatially informed miRNA therapeutics for precision oncology. Continued optimization of biocompatibility, delivery efficiency, and targeting specificity, combined with multi-omics-driven design, will be pivotal for realizing the full therapeutic potential of miRNAs in clinical cancer management.

Future directions

Future research should address the biological and technical barriers to clinical translation of miRNA-based therapies in BC. A key focus should be on the context-dependent behavior of miRNAs, as several miRNAs exhibit dual functionality-acting as tumor suppressors in some contexts and as oncogenes in others [98]. This highlights the need to investigate subtype-specific expression and functional roles of miRNAs in luminal, HER2-positive, and TNBC subtypes. Another promising area is elucidating miRNA expression dynamics in response to standard therapies, such as chemotherapy, radiotherapy, and immunotherapy. Understanding how miRNAs influence or respond to treatment-induced NF-κB activation may help overcome resistance mechanisms [17–20]. Numerous studies have demonstrated that combining miRNA therapeutics with immunotherapy provides a synergistic and precision-driven approach to cancer treatment. For instance, miRNAs modulate critical immune checkpoint pathways, including the PD-1/PD-L1 and CTLA-4 axes, reprogram the tumor microenvironment, and enhance T-cell-mediated antitumor immunity, overcoming immune evasion and sensitizing refractory tumors to checkpoint blockade. Moreover, co-delivery systems employing nanoparticles or exosomes facilitate simultaneous delivery of miRNAs with immune agents, improving therapeutic efficacy and minimizing immune resistance [144, 145]. Further, studies have emphasized that miRNAs such as miR-34a and miR-155 modulate CTLA-4 and PD-1/PD-L1 signaling to potentiate immune responses; integrating miRNA mimics or inhibitors with checkpoint inhibitors enhances T-cell activation and immunotherapy responsiveness, offering a next-generation personalized immune-oncology strategy [146, 147].

Further, studies on the miRNA-PD-1/PD-L1 axis demonstrate that TS-miRs downregulate PD-L1, augment CD8⁺ T-cell activation, and sensitize tumors, such as NSCLC, to checkpoint blockade therapy. At the same time, oncogenic miRNAs promote immune escape through PD-L1 upregulation [148]. Vaxevanis et al. highlighted that immune-modulatory miRNAs, such as miR-34a, miR-16, miR-155, and miR-146a, orchestrate immune checkpoint regulation (CTLA-4, LAG-3, PD-1/PD-L1, TIM-3) and can be harnessed in combined miRNA-immunotherapy or CAR-T cell platforms to enhance immune activation, reverse T-cell exhaustion, and achieve durable antitumor responses [149]. Thus, integrating miRNA therapeutics with immunotherapy offers a compelling strategy to overcome resistance and achieve personalized, durable cancer control.

In parallel, high-resolution tools such as single-cell transcriptomics and spatial omics can provide valuable insights into miRNA-mediated signaling within the tumor microenvironment, revealing cellular heterogeneity and intercellular communication [139, 150]. Building on these advances, recent developments in spatial miRNomics have enabled the exploration of miRNA expression and activity within their native tissue context. Robles-Remacho et al. comprehensively reviewed the emerging technologies for spatially resolved miRNA profiling, highlighting both imaging-based approaches, such as LNA-ISH and miRNAscope, and sequencing-based strategies, including STRS and Patho-DBiT, that allow miRNA detection while preserving spatial architecture. Patho-DBiT is the first method to achieve high-throughput spatial miRNA mapping in FFPE tissues, identifying region-specific and disease-associated miRNA signatures [151]. Complementing these experimental advances, Herbst et al. introduced miTEA-HiRes, a computational framework that infers miRNA activity, rather than mere expression, by assessing the coordinated downregulation of miRNA target transcripts in single-cell and spatial RNA-sequencing data. This approach enables creating high-resolution miRNA activity maps, revealing tissue- and disease-specific regulatory patterns and uncovering differentially active miRNAs in conditions such as multiple sclerosis and BC metastasis [150]. Together, these integrative advances enable spatially resolved miRNA functional mapping, providing opportunities to discover precision biomarkers and therapeutic targets in cancer.

Integrating multi-omics platforms will further enable the construction of comprehensive regulatory networks linking miRNAs, mRNAs, proteins, and signaling pathways, thus facilitating the prediction of therapeutic outcomes [152]. Combining miRNA therapeutics with immune checkpoint blockade or standard therapies could yield synergistic effects and improve clinical responses [133, 136–138]. Developing efficient, targeted, and biocompatible miRNA delivery systems remains a priority to achieve these goals. Approaches such as engineered nanoparticles, EVs, and scaffold-based platforms are actively explored to enhance delivery precision and minimize systemic toxicity [133–135, 139–141]. Comprehensive preclinical validation followed by meticulously designed clinical trials is crucial to ascertain the safety, target specificity, and therapeutic efficacy of these interventions. In summary, miRNAs represent a promising therapeutic paradigm across multiple cancers, including BC, owing to their ability to modulate key oncogenic signaling pathways such as NF-κB. However, the successful clinical translation of miRNA-based therapies requires continued progress in elucidating miRNA biology, optimizing delivery technologies, and addressing tumor heterogeneity. Advancements in these areas will be crucial for transforming miRNA research into safe, targeted, and effective clinical interventions.

Discussion and conclusion

BC remains a major global health burden, representing the second most commonly diagnosed cancer worldwide, accounting for nearly 11.6% of new cancer cases in 2022, with approximately 2.3 million diagnoses. Its multifactorial etiology encompasses hormonal, genetic, and lifestyle risk factors, along with dysregulated intracellular signaling cascades that drive tumorigenesis. Among these, the NF-κB signaling pathway plays a central role in BC pathogenesis, contributing to chronic inflammation, apoptosis resistance, metastasis, and therapeutic failure. Mounting evidence indicates that miRNAs, particularly oncomiRs and TS-miRs, act as key modulators of NF-κB signaling. By influencing transcriptional regulators and post-transcriptional checkpoints, miRNAs can either promote or inhibit NF-κB activation, thereby impacting major cancer hallmarks such as proliferation, invasion, drug resistance, etc.

Studies have demonstrated that distinct miRNAs, including miR-621, miR-30b-5p, or miR-150, can modulate components of the NF-κB pathway to enhance chemosensitivity and apoptosis, suggesting their therapeutic potential [29, 30, 153]. However, clinical translation of miRNA-based therapies faces challenges related to stability, targeted delivery, immune activation, and off-target gene silencing. Innovative nanoparticle, exosome, and scaffold-based delivery systems, as well as single-cell and spatial omics-guided approaches, are helping overcome these limitations, enabling precision-targeted modulation of oncogenic signaling networks [156, 154].

The clinical evaluation of miRNA therapeutics, such as MRX34 (a miR-34a mimic), has demonstrated encouraging outcomes across multiple tumor types, suggesting a viable framework for personalized cancer therapy [32, 155]. Moving forward, integrating multi-omics platforms, spatial miRNomics, and immunotherapy combinations will be crucial to harness the full potential of miRNAs as diagnostic biomarkers and therapeutic agents. Collectively, the dual regulatory nature of miRNAs in NF-κB signaling represents a promising frontier in precision oncology, with the potential to redefine therapeutic strategies and improve long-term outcomes in BC management.

Abbreviations

AAV

Adeno-associated virus

BC

Breast cancer

cIAP1/2

Cellular inhibitor of apoptosis 1/2

circRNA

Circular RNA

EMT

Epithelial-to-mesenchymal transition

ESA

Epithelium-specific antigen

EV

Extracellular vesicles

IBD

Inflammatory bowel disease

IKBKB

Inhibitor of nuclear factor kappa B kinase subunit beta

IKKβ

IκB kinaseβ

IRAK1/4

IL-1 receptor-associated kinase 1/4

lncRNA

Long non-coding RNA

m⁷G

7-methylguanosine

miRNA

MicroRNA

MTMR3

Myotubularin-related protein 3

MyD88

Myeloid differentiation primary response gene 88

ncRNA

Noncoding RNA

NEMO

NF-κB essential modulator

NF-κB

Nuclear factor kappa-light-chain-enhancer of activated B cells

NIK

NF-κB-inducing kinase

OncomiR

Oncogenic microRNA

piRNA

Piwi-interacting RNA

PKCθ

Protein kinase C-θ

RAGE

Receptor for advanced glycation end products

RANK

Receptor activator of nuclear factor κB

RHD

Rel homology domain

RIP1

Receptor-interacting protein 1

RISC

RNA-induced silencing complex

SIX1

Sine oculis homeobox 1

SND1

Staphylococcal nuclease and tudor domain-containing 1

TAK1

TGF-β-activated kinase 1

TCRs

T cell receptors

TFs

Transcription factors

TGFβ

Transforming growth factorβ

TIRAP

Toll/IL-1 receptor adaptor protein

TLR4

Toll-like receptor 4

TRADD

TNF-R-associated death domain

TRAF2/5/6

TNF-R-associated factors

TRAM

TRIF-related adaptor molecule

TS-miR

Tumor suppressor microRNA

UTR

Untranslated region

VLP

Virus-like particle

ZFP91

Zinc finger protein 91

Author contributions

**MKM** conducted the investigation, prepared the original draft, performed visualization, and prepared the tables. **RV** contributed to the original draft writing and was involved in manuscript review and editing. **AS** participated in writing the original draft and in reviewing and editing the manuscript. **AG** contributed to the manuscript review and editing and prepared the figures. **MSA** and **MA** were involved in reviewing and editing the manuscript. **VT and GS** were responsible for conceptualization, supervision, and funding acquisition, and contributed to reviewing and editing the manuscript. **ZM** and **ABK** provided conceptualization, supervision, and funding acquisition, and were major contributors in reviewing and editing the manuscript. All authors read and approved the final manuscript.

Funding

The authors disclose receipt of the following financial support for the research, authorship, and/or publication of this article. This work was supported by Ajaikumar B. Kunnumakkara’s Professional Development Fund (PDF), BSBE/ABK/01 from IIT Guwahati.

Data availability

Not applicable.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.