Targeting cuproptosis for treatment and prognostic assessment in endometrial cancer

Abstract

Endometrial Cancer is a prevalent malignant tumor in gynecology, marked by high incidence and poor prognosis. The discovery of cuproptosis, a copper-dependent cell death pathway, offers new therapeutic potential. We systematically reviewed literature on cuproptosis mechanisms in endometrial cancer, including copper metabolism dysregulation, prognostic biomarkers, and therapeutic strategies. Then we identified three key findings: (1) Copper homeostasis disruption promotes cancer via angiogenesis, metastasis, and chemoresistance; (2) Cyclin-dependent kinase inhibitor 2 A and glutaminase exhibit strong prognostic predictive value; (3) The strategy of regulating copper homeostasis exhibits anticancer effects. Cuproptosis targeting represents a promising strategy for endometrial cancer management. Further clinical validation of cuproptosis-related biomarkers and optimization of combination therapies are warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-025-04057-6.

Introduction

Endometrial cancer (EC) represents the fourth most commonly diagnosed gynecological malignancy, accounting for the fifth most frequent cause of cancer death among women [1]. The rising incidence of EC is likely attributed to factors such as the increasing prevalence of obesity, nulliparity, and early menarche [2, 3]. Although curative surgery (often supplemented by adjuvant treatments like chemotherapy or radiotherapy) remains the first-line therapy for EC [4, 5], persistently high incidence, recurrence, and mortality rates have driven an urgent exploration of new diagnostic and treatment strategies [1, 6, 7]. Consequently, exploring the molecular mechanisms underlying EC development, particularly in relation to cell death, is essential. Identifying new candidate genes is crucial for improving early diagnosis and guiding treatment strategies.

In recent years, programmed cell death (PCD)-encompassing apoptosis, ferroptosis, and necrosis-has garnered significant attention in cancer research for its promising potential treatment prospects [8]. In March 2022, Tsvetkov Pde et al. reported in Science that cuproptosis, a newly identified form of PCD, is distinct from other cell death mechanisms, and is driven by mitochondrial respiration [9]. Specifically, cuproptosis occurs when copper binds directly to lipoylated components of the tricarboxylic acid (TCA) cycle. This process leads to the accumulation of lipoylated proteins and subsequent reduction of iron-sulfur cluster proteins, inducing proteotoxic stress and ultimately cell death [10]. Emerging evidence indicates that copper plays a pivotal role in tumorigenesis and cancer progression [11–14]. However, studies exploring the role of Cuproptosis-Related Genes (CRGs) in the development and prognosis of EC remain scarce.

This review aims to provide an overview of the basic concepts of cuproptosis and its recent advancements in EC research. It focuses on the role of copper in cancer and its therapeutic implications, including drug development targeting cuproptosis pathways and combination therapy strategies. Furthermore, the article summarizes prognostic models based on CRGs that have been developed for EC and explores their potential applications in clinical risk assessment, diagnosis and therapy. Ultimately, this review could provide a new theoretical foundation and practical insights for the precise treatment and prognosis evaluation of EC.

Copper homeostasis

Copper (also known as Cu) is an essential trace element, playing a crucial role in numerous physiological processes, including redox reactions, mitochondrial respiration, antioxidant defense, and autophagy. The recommended daily intake of copper for adults ranges from 0.8 to 2.4 mg [15]. In humans, absorption of dietary copper occurs primarily in the small intestine, where the high-affinity copper transporter Solute carrier family 31 member 1 (SLC31A1, also known as copper transporter 1 (CTR1)) mediates cellular uptake. Then, Cu is transported by antioxidant-1 (ATOX1) and released into the bloodstream through ATPase copper transporting A (ATP7A). Most copper is stored in the liver, regulated by ATPase copper transporting B (ATP7B). Excess copper is exported into the bile and eliminated from the body via fecal excretion [16]. The intracellular copper homeostasis, as shown in Fig. 1 [17]., is collaboratively achieved by the most important copper transporters such as SLC31A1, ATP7A, and ATP7B. In normal cells, SLC31A1 primarily mediates cellular copper uptake, while ATP7A and ATP7B serve dual functions of both copper export and acting as metal chaperone proteins. Through the interactions among these proteins, cellular homeostasis of copper is maintained, preventing its toxic accumulation within the cell. Conversely, disruption of copper homeostasis can result in metabolic disorders and even trigger cell death. Multiple studies suggest that CRGs may be involved in cancer progression. For instance, increased expression of SLC31A1 has been observed in endometrial carcinoma [18], and elevated levels of ATP7A have been reported in prostate cancer [19], further supporting this notion.

Fig. 1.

Copper distribution pathways within a generalized cell. Extracellular copper is reduced from Cu²⁺ to Cu⁺ by the reductase six-transmembrane epithelial antigen of the prostate (STEAP). Cells primarily take up the resulting Cu⁺ through the copper transporter SLC31A1. Once inside the cell, Cu⁺ associates with cytosolic copper chaperones (copper chaperone for superoxide dismutase (CCS), cytochrome c oxidase assembly factor 17 (COX17), and ATOX1) and potentially other soluble proteins. The chaperone CCS specifically delivers copper to cytosolic superoxide dismutase 1 (SOD1). Additionally, ATOX1 delivers copper to the transporters ATP7A and ATP7B, which then transfer copper to cuproenzymes within the lumen of the Trans-Golgi Network (TGN). With the increase of cellular Cu, ATP7A and ATP7B relocate from the TGN to vesicles where they sequester excess Cu and ultimately export it out of cells. If copper levels are within physiological range, they return to the TGN. Furthermore, ATOX1 transports copper in a tumor necrosis factor receptor-associated factor 4 (TRAF4)-facilitated fashion and collaborates with CCS to facilitate intracellular copper transport to the nucleus. In the mitochondria, Cu can bind to cytochrome c oxidase (CCO), contributing to the respiratory chain and redox pathways. COX17, located in the mitochondrial intermembrane space, can help transfer Cu to SCO1 or cytochrome c oxidase assembly factor 11 (COX11), which subsequently deliver it to cytochrome oxidase subunits. To prevent copper toxicity, excessive intracellular copper can be chelated by metallothioneins 1 and 2 (MT 1/2) as well as glutathione (GSH). (Created in BioRender.com).

Copper levels in endometrial cancer

Recently, the role of copper in cancer research has gained more attention. In patients with oral cancer [20], thyroid cancer [21], lung cancer [22], breast cancer [23], and ovarian cancer [24], the serum copper levels are elevated. However, the research findings regarding serum copper levels in EC patients remain inconsistent. Most studies report that EC patients have elevated serum copper levels [25–28], while a minority indicate lower serum copper levels compared to control groups [29, 30]. Furthermore, some research has found no significant correlation between the two groups [24, 31]. Certain investigations suggest a positive correlation between serum copper concentration and EC risk [28]; however, Haruna I and colleagues did not identify any significant association between copper levels and the staging of EC [32]. These discrepancies may be attributed to confounding variables such as body mass index (BMI), age, and menopausal status. For instance, Atakul T et al. found a positive correlation between copper levels and the age of EC patients [29]; Michalczyk K et al. reported that for EC patients, both elevated BMI and postmenopausal condition are associated with increased concentrations of Cu and Zn and their ratio [33]. In conclusion, copper dysregulation offers new prospects for future research in the diagnosis and treatment of EC, while the current body of evidence highlights significant inconsistencies, underscoring the need for more comprehensive and rigorous investigations. This may also suggest that the role of copper in EC is comparatively less pronounced than in other cancers.

The role of copper in cancer mechanisms

As illustrated in Fig. 2, dysregulation of copper facilitates cancer progression by promoting tumor growth, proliferation, angiogenesis, and metastasis via multiple signaling pathways [34, 35]. The specific mechanisms are outlined below:

Fig. 2.

Core mechanisms of cuproptosis in cancer. Cu²⁺ enters mitochondria using the copper ionophores. Inside, ferredoxin 1 (FDX1) reduces Cu²⁺ to Cu⁺, which in turn induces mitochondrial proteotoxic stress by promoting protein lipoylation and facilitating the oligomerization of dihydrolipoamide S-acetyltransferase (DLAT). FDX1 further modulates lipoylation by binding to lipoic acid synthetase (LIAS), thereby stabilizing its interaction with the glycine cleavage system H protein (GCSH). An auxiliary Fe-S cluster in LIAS supplies essential sulfur atoms and must be rebuilt after each reaction cycle. The interruption of Fe-S cluster biosynthesis reduces sulfur atom availability, consequently decreasing protein lipoylation. As a result, enhanced degradation of Fe-S cluster proteins impedes cuproptosis. However, the main mechanisms of cuproptosis are still unclear. It is evident that glycolysis can effectively suppress cuproptosis, a process that is significantly enhanced by the activation of hypoxia-inducible factor 1 alpha (HIF-1α) induced by hypoxic conditions. Adenosine monophosphate-activated protein kinase (AMPK) serves as a critical metabolic regulator in cuproptosis: short-term activation reduces protective toxic stress, but sustained activation during glucose starvation inhibits glycolysis and promotes cell death. (Created in BioRender.com)

Firstly, cuproplasia is a newly discovered form of copper-mediated regulated cell growth and proliferation that includes hyperplasia and neoplasia. This process is associated with various cellular functions, such as redox signal transduction, kinase signaling pathways, protein quality control, antioxidant defense mechanisms, and mitochondrial respiration [13]. However, excessive copper can induce cuproptosis, particularly through a mitochondrial pathway characterized as “cuproplasia” [10, 13]. Tumors require elevated copper levels to support proliferation, a process that involves altered expression of chaperone proteins and transport pumps responsible for copper uptake, distribution, and export. This dysregulation further promotes cancer progression [36]. Elevated expression of SLC31A1 has been observed in EC [37]. Specifically, the overexpression of ATP7A and ATP7B reduces intracellular copper levels, thereby inhibiting cuproplasia. In contrast, overactivation of SLC31A1 can enhance intracellular copper levels, thereby promoting cuproptosis [38].

Secondly, Cu promotes cancer metastasis, a key factor in cancer-related deaths [39]. Cu is essential for the function of various metalloenzymes, such as matrix metalloproteinase (MMP-9), lactic oxidase (LOX), and superoxide dismutase 1 (SOD1), which are integral to the metastatic process [34]. It is noteworthy that copper exhibits dual regulation of cancer metastasis: it can promote metastasis by activating proliferation and metabolism-related enzymes, while possibly inhibiting the metastatic process at certain stages. For example, LOX, an extracellular copper-dependent enzyme responsible for crosslinking collagen and elastin in the extracellular matrix (ECM), plays a crucial role in ECM remodeling processes [40]. Moreover, ECM remodeling is crucial for tumor metastasis. Overactivation of lysyl oxidase-like 2 (LOXL2) has been shown to reduce cancer cell proliferation in vitro and inhibit xenograft tumor growth in vivo [41]. This highlights the complexity of copper dependence in cancer metastasis regulation.

Thirdly, Cu promotes angiogenesis by regulating various factors, including the Cu chaperone ATOX1, the inflammatory cytokine IL-1α and fibroblast growth factor (FGF) [42–45]. Copper-driven angiogenesis plays a critical role in tumor initiation, growth, and metastasis by activating angiogenic factors [46, 47].

Fourthly, Cu is involved in chemoresistance. Cu transporters such as SLC31A1, ATOX1, and ATP7A and ATP7B play crucial roles in cisplatin transport, indicating that copper homeostasis regulation may influence the effectiveness of platinum-based chemotherapy [48–50]. Thus, targeting the copper transport system may enhance the efficacy of platinum-based chemotherapy for cancer.

Fifth, Cu contributes to cancer immune evasion by upregulating the expression of programmed cell death ligand 1 (PD-L1) in cancer cells [51]. However, its impact on immunotherapy exhibits marked variability. For instance, a study by Zhao M et al. suggests that patients with high Glycine cleavage system H protein (GCSH) exhibited insensitivity to common immune therapies like anti-PDL1 [52]. Conversely, research conducted by Nie H et al. reveals that gastric cancer patients with high copper death scores had higher responses to immunotherapies such as adoptive T-cell therapy and anti-PD-L1 therapy [53]. These findings suggest that the role of cuproptosis in tumor treatment is complex and requires further exploration as a potential therapeutic application.

Prognostic models for endometrial cancer

The clinical management of EC faces significant challenges due to the absence of reliable prognostic biomarkers. To address this gap, we summarized articles on bioinformatics risk prediction models for prognosis and survival in EC patients based on the expression levels of CRGs (Table 1), using datasets from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO). Notably, these models not only demonstrate clinical value in accurately predicting prognosis but also deepen comprehension of the fundamental mechanisms involved in copper-induced cell death, offering potential pathways for early diagnosis and targeted therapies of EC [18, 52, 54–58]. These findings lay a crucial foundation for developing innovative therapeutic strategies based on the regulation of copper-induced cell death.

Table 1.

Prognostic prediction model for EC patients based on gene expression

Author	Databases	Prognostic genes	Gene set enrichment analysis
Huang et al. [55]	TCGA	CDKN2A, GLS, PPAT	Functional analysis of CDKN2A, GLS, and PPAT showed their roles in pathways like the TCA cycle, pyruvate metabolism and resistance to platinum-based chemotherapy. The binding of iron-sulfur clusters and metal clusters represents a significant aspect of their molecular functions. The three genes were significantly linked to immune infiltration levels in EC.
Zhao et al. [52]	TCGA, GEO (GSE40032, GSE63678)	GCSH	Enrichment analysis identified high GCSH as linked to immune suppression. Additionally, high GCSH correlated with a non-inflamed tumor microenvironment (TME), resulting in the reduction of immune cell infiltration. Ultimately, patients exhibiting elevated GCSH expression demonstrated reduced sensitivity to both immunotherapy and chemotherapy.
Ran et al. [58]	TCGA	GLS, CDKN2A, PDHX, SUCLG1, TRAF4	Gene Ontology (GO) enrichment analysis indicated that these genes were significantly associated with metal cluster binding, iron-sulfur cluster binding, the mitochondrial matrix, the oxidoreductase complex, and the TCA cycle enzyme complex. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed their involvement in carbon metabolism, the citrate cycle and glycolysis/gluconeogenesis.
Pang X et al. [56]	TCGA, GEO(GSE154763)	CDKN2A, PDHA1, GLS, DBT, SLC31A1	These genes were associated with immune infiltration.
Lin S et al. [54]	TCGA	GLS, CDKN2A, PC, SUCLG1	Functional enrichment analysis indicated that these genes are predominantly involved in pathways related to intercellular adhesion and immune activities, such as the IL-1 signaling pathway. Furthermore, as disease progresses, differentiation decreases, patient age increases and resistance to initial treatment rises, higher risk score cohorts can be observed in both training and testing.
Chen Y et al. [57]	TCGA	CDKN2A, GLS, LIPT1	High expressions of GLS, CDKN2A, and LIPT1 are associated with poor prognosis in EC. Immune infiltration analysis revealed that the expressions of GLS, CDKN2A, and LIPT1 were positively correlated with the abundance of certain immune cells, particularly CD8 + T cells and neutrophils.
Wu Q et al. [18]	TCGA, GEO(GSE17025)	ATP7B, PDHA1, SLC31A1, ATP7A, DLST, GCSH, LIAS, LIPT1	GO enrichment analysis indicated that these genes predominantly are associated with aspects such as cell-cell junctions, axonogenesis, and growth factor binding. KEGG enrichment analysis showed a significant association with axon guidance, the cell cycle, and transcriptional misregulation in cancer.

As summarized in Table 2, we identified 16 key CRGs related to EC, including CDKN2A, GLS, GCSH, LIPT1, PDHA1, SLC31A1, SUCLG1, ATP7A, ATP7B, DBT, DLST, LIAS, PC, PDHX, and PPAT. These genes play crucial roles in vital biological pathways, including carbon metabolism, glycolysis/gluconeogenesis, platinum-based drug resistance, the TCA cycle, and transmembrane transport of metal ions. Among them, CDKN2A and GLS have the highest mutation rates, followed by GCSH, LIPT1, PDHA1, SLC31A1, and SUCLG1. Mutations in the remaining CRGs occur at relatively lower frequencies. Next, we compared the differential gene expression between EC tissues and normal endometrial tissues. Results indicated that ATP7B, CDKN2A, GLS, PC, PDHA1, PPAT, SLC31A1, and SUCLG1 were significantly upregulated, while ATP7A, DBT, DLST, GCSH, LIAS, and LIPT1 were notably downregulated. Additionally, the expression of GLS displayed instability requiring further clarification. No clear information has yet been provided regarding PDHX and TRAF4. We also examined the relationship between CRGs and prognosis risk. Our study found that PDHX and SLC31A1 were negatively correlated with prognosis risk, while ATP7A, ATP7B, CDKN2A, DLST, GCSH, GLS, LIAS, LIPT1, PC, PDHA1, PPAT, SUCLG1, and TRAF4 showed positive correlations with prognosis risk. The relationship between DBT and prognostic risk remains unclear. Interestingly, Chen et al. identified three clusters (A, B, and C) of CRGs based on ten CRGs (including CDKN2A, DLAT, DLD, FDX1, GLS, LIAS, LIPT1, MTF1, PDHA1, and PDHB) and evaluated their prognosis and immunotherapy effects in EC patients. The analysis showed that the CRG cluster A was significantly enriched in metabolic-related pathways. In contrast, the CRG cluster C correlated with cellular activities such as cell cycle progression, DNA replication, and RNA degradation. Furthermore, the analysis indicated that CRG cluster C exhibits minimal enrichment in various innate immune cells, including activated CD8⁺ T cells, activated CD4⁺ T cells, natural killer cells, and T helper cells. This may explain why patients categorized under CRG cluster C experience the poorest survival outcomes [59]. It is noteworthy that a higher prognosis risk correlates with poorer survival for patients, implying that these CRGs could serve not only as potential therapeutic targets but also as significant indicators for disease progression.

Table 2.

The role and clinical value of CRGs in EC

Gene	Full name	Subcellular	Functions	Role in cuproptosis	Clinical values
CDKN2A [74]	Cyclin-dependent kinase inhibitor 2 A	Nucleus	High-affinity copper transporter for dietary absorption	Overactivation leads to intracellular copper accumulation	CDKN2A is upregulated in EC and correlated with poor survival prognosis, potentially related to the tumor immune landscape and autophagy.
GLS [75]	Glutaminase	Mitochondria	Key genetic regulator of the pyruvate dehydrogenase (PDH) complex	Linking the TCA cycle to glycolysis and fat and amino acid metabolism	GLS expression in EC is lower than in normal tissues, and elevated GLS levels in EC patients are associated with poorer overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI) outcomes.
LIPT1 [18]	Lipoyltransferase 1	Mitochondrion	Regulating glutamine metabolism via acyl transfer catalysis	Regulated by FDX1 and involved in the lipid acylation of DLAT	LIPT1 is found to be overexpressed in patients with poor prognosis.
PDHA1 [18, 76]	Pyruvate dehydrogenase E1 subunit alpha 1	Mitochondrion matrix	Components the pyruvate dehydrogenase complex(PDC)	Key enzyme in the TCA cycle	Patients with advanced EC (older age, higher grades, and/or stages) show significant upregulation of PDHA1 expression and a poorer prognosis.
LIAS [18, 77]	Lipoic acid synthase	Mitochondrion	Participating in mitochondrial enzyme synthesis, energy metabolism, and antioxidant reactions.	FDX1-regulated downstream gene	LIAS is down-regulates in EC.
SLC31A1 [18]	Solute carrier family 31 (copper transporter), member 1	Cell membrane	High-affinity, saturable copper transporter involved in dietary copper uptake	Overactivation leads to intracellular copper accumulation	Higher SLC31A1 expression is linked to better prognosis in EC.
SUCLG1 [58, 78]	Succinate-coA ligase GDP/ADP-forming subunit alpha	Mitochondrion matrix	Restricting succinyl-CoA levels to suppress the succinylation of mitochondrial RNA polymerase	Connecting succinyl-CoA with POLRMT succinylation to modulate mitochondrial function and cancer development	High SUCLG1 expression in EC patients correlates with decreased B cell and CD4 + cell counts, as well as reduced survival time and rates.
ATP7A [18, 79]	ATPase copper transporting A	Cell membrane, trans-Golgi network membrane, plasma membrane	ATP-driven copper pump	Knockout-mediated copper accumulation	ATP7A is lower in tumor tissues, and patients with high ATP7A levels have a worse prognosis.
ATP7B [18, 79]	ATPase copper transporting B	Cell membrane, trans-Golgi network membrane, plasma membrane	ATP-driven copper pump	Knockout-mediated copper accumulation	ATP7B is up-regulated in tumor tissues, correlating with poor prognosis for patients with high ATP7B levels. Conversely, patients with mutant ATP7B show better outcomes than those with wild-type ATP7B.
DBT [80]	Dihydrolipoamide branched chain transacylase E2	Mitochondrion	Key component of branched-chain alpha‐keto acid dehydrogenase complex	Loss of DBT causes mitochondrial dysfunction, resulting in the accumulation of ROS and apoptosis	Not Available.
DLST [81]	Dihydrolipoyllysine-residue succinyltransferase	Mitochondrion matrix	Key component of α-ketoglutarate dehydrogenase complex (KGDHC)	Key enzyme involved in the TCA cycle	DLST is down-regulated in tumor tissues, and patients with high levels of DLST expression have a poorer prognosis.
GCSH [52]	γ-glutamylcysteine synthetase	Mitochondrion	Key component of the Glycine Cleavage System (GCS)	Modulating oxidative stress	GCSH expression is significantly upregulated in EC. High GCSH expression are associated with poor prognosis, immune suppression, and a non-inflammatory TME in EC patients, as well as resistance to immunotherapy and chemotherapy.
PC [82]	Pyruvate carboxylase	Mitochondrion matrix	A widely expressed mitochondrial enzyme	Catalyzing the carboxylation of pyruvate to oxaloacetate and replenishing TCA cycle intermediates	PC is highly expressed in patients with poor prognosis.
PDHX [83]	Pyruvate dehydrogenase complex component X	Mitochondrion matrix	An E3-binding protein in the PDC	Key enzyme linking glycolysis and the TCA cycle	Low PDHX expression in EC is associated with a significant decrease in the number of B cells and CD4 + cells, as well as reduced survival time and rates.
PPAT [84]	Phosphoribosyl pyrophosphate amidotransferase	Cytoplasm	Key metabolic enzyme in de novo purine synthesis	Purine synthesis	PPAT is highly expressed in patients with poor prognosis.
TRAF4 [85]	TNF receptor-associated factor 4	Cytoplasm, Plasma Membrane	E3 ubiquitin ligase	Regulating the adipogenic differentiation of Mesenchymal Stem Cells by activating PKM2	High TRAF4 expression in EC is associated with a significant decrease in the number of B cells and CD4 + cells, as well as reduced survival time and rates.

The most frequently identified prognostic genes in EC are CDKN2A and GLS, which play significant roles in key biological pathways such as glycolysis/gluconeogenesis, metal ion transmembrane transporter activity, and the TCA cycle [55]. Mechanistic studies indicate that silencing CDKN2A reduces the expression of the rate-limiting enzyme phosphofructokinase-1. This results in the inhibition of glycolytic activity. Additionally, silencing CDKN2A can alter the expression profiles of Cu transport genes, specifically ATP7B and SLC31A2. ATP7B, as a copper-transporting ATPase, plays a crucial role in facilitating the excretion of intracellular copper or its transport into the lysosomal lumen. In contrast, SLC31A2 transports copper ions from lysosomes back into the cytoplasm [60]. Ultimately, CDKN2A is essential for regulating intracellular copper levels and facilitating its directional transport. Meanwhile, GLS, as a key genetic regulator of the pyruvate dehydrogenase (PDH) complex, plays a crucial role in the rate-limiting step in mitochondrial pyruvate decarboxylation. This process intricately connects the TCA cycle with glycolysis, as well as fat and amino acid metabolism [61]. Therefore, overactivation of CDKN2A and GLS ultimately leads to severe toxic protein stress, triggering cell death.

Although many bioinformatics studies have identified new CRG-based prognostic models in EC, experimental validation using cell lines or clinical samples is still limited. While bioinformatics offers promising avenues for future research, further experimental investigations are needed to assess the reliability and therapeutic significance of these molecules.

Targeting cuproptosis for potential endometrial cancer treatment

Cu toxicity, as a promising cancer treatment strategy, is receiving more attention. Copper chelators and copper ionophores represent two primary strategies for targeting copper homeostasis. Cu chelators can reduce the bioavailability of intracellular copper ions by binding to them, thereby inhibiting cuproplasia. In contrast, copper ionophores refer to compounds or chemical substances that can enhance intracellular copper levels, leading to the induction of cuproptosis [34]. These copper-based drugs can serve as a starting point for optimizing therapies or be used in combination with anticancer agents.

Copper chelator

Copper chelators, exemplified by Tetrathiomolybdate (TTM), have shown promising therapeutic potential in cancer treatment. TTM suppresses mitochondrial complex IV activity and facilitates the breakdown of hypoxia-inducible factor-1α (HIF-1α) in cancer cells, thereby impairing the activation of its transcriptional targets related to glucose metabolism and angiogenesis. Therefore, TTM demonstrates potential as a therapeutic approach for inhibiting angiogenesis in EC [62]. In addition, TTM has been shown to enhance p38 mitogen-activated protein kinase (MAPK) activation following cisplatin treatment, which in turn promotes epidermal growth factor receptor (EGFR) degradation. This suggests that TTM may potentiate the efficacy of cisplatin by facilitating EGFR downregulation [63]. Furthermore, a study conducted by Ryumon S et al. has discovered that TTM can overcome cisplatin resistance in head and neck squamous cell cancer in vitro [64]. Recently, the dynamic therapy mediated by nanosensitizers utilizing copper complexes has been playing crucial roles in conquering tumors. In vivo experiments using mouse models, Cu@CPP-800 exhibits remarkable tumor ablating capabilities [65]. In addition, the copper chelator can attenuate the tumor-promoting signals mediated by PD-L1 expression through its inhibition, thereby alleviating tumor immune evasion and ultimately enhancing the efficacy of immunotherapy [51]. A noteworthy finding is that copper-containing intrauterine devices (IUDs) may not only serve contraceptive purposes but also exhibit potential preventive and therapeutic effects against cervical cancer and endometrial cancer [38]. However, existing studies have not observed significant alterations in serum copper concentrations or detectable cytotoxic effects associated with the use of such IUDs [66, 67]. We hypothesize that combining targeted copper therapy with immunotherapy may further enhance antitumor efficacy; however, whether this mechanism operates through pathways involving copper toxicity still requires validation through additional research.

In conclusion, TTM has shown significant preclinical efficacy as a classical copper chelator in EC. However, its clinical application faces some key challenges, such as stability of in vivo efficacy, precise elucidation of molecular mechanisms, and optimization of combination therapy. Current evidence supporting its efficacy mainly comes from in vitro cell experiments and animal model studies, with a lack of clinical-grade data validation.

Copper ionophores

Copper ionophores such as elesclomol (ES) and disulfiram (DSF) can induce cuproptosis, thereby demonstrating their anticancer potential.

ES facilitates the transport of excessive intracellular Cu²⁺ ions into the mitochondria, where FDX1 subsequently reduces Cu²⁺ to Cu⁺. Elevated levels of Cu⁺ directly interacts with lipoylated DLAT, resulting in the aggregation of lipoylated proteins and instability of Fe-S cluster proteins. This cascade leads to proteotoxic stress, ultimately inducing cuproptosis (see Fig. 2) [9]. To enhance the precision of copper delivery, specially designed nanodrug delivery systems have been developed. Zeng Y et al. developed a GSH-responsive prodrug hybridization nanoassembly CA-4S2@ES-Cu, which targets the delivery of copper ions to mitochondria via ES and then contributes to mitochondrial dysfunction and inducing copper toxicity events. Simultaneously, CA-4S2 releases CA-4 by depleting GSH, to disrupt microtubule function and suppress HCC cell proliferation and angiogenesis. This approach achieves a dual attack against deterioration and metastasis mediated by copper ions [68]. Copper ionophores can also interact with other forms of regulated cell death, such as ferroptosis and apoptosis. For example, ES can induce ferroptosis, enhancing its anticancer efficacy. ES can increase mitochondrial Cu²⁺ concentration and downregulate ATP7A expression, leading to increased intracellular Cu²⁺ and elevated accumulation of reactive oxygen species (ROS), and eventually causing SLC7A11 degradation and ferroptosis in cells [9]. Cuproptosis can amplify the cytotoxic effect of conventional chemotherapeutic agents. The research conducted by Zou Q et al. suggests that the combination of ES and cisplatin may be a promising therapy for ovarian cancer [69].

DSF, an FDA-approved medication originally used to treat alcohol dependence, has demonstrated potential anticancer activity through its modulation of redox-related cellular processes. It also alters cellular glutathione and other redox thiol proteins, thereby affecting mitochondrial permeability. Ultimately, these changes may induce apoptosis in the affected cells [70]. The mechanism elucidates how DSF improves the antitumor efficacy and sensitivity of hepatocellular carcinoma in mice to 5-FU through redox management [71]. Additionally, the DSF/Cu complex has demonstrated considerable cytotoxicity against cancer cells while maintaining safety for normal cells [38]. The mechanism elucidates the combination of CuCy and DSF induces mitochondrial impairment in Ishikawa cells, thereby promoting apoptosis and ultimately achieving a significant anti-tumor effect [72].

A combination treatment strategy with chemotherapeutic drugs or targeted agents enhances therapeutic efficacy. Copper transporters ATP7A/B are known to mediate chemotherapeutic cancer resistance. It can be observed that high expression levels of ATP7A/B confer resistance to platinum-based chemotherapeutic drugs in cells. Accordingly, ES stimulates the degradation of ATP7A, enhancing sensitivity to chemotherapy [73]. In EC, this multi-mechanism synergy demonstrates significant anti-cancer potential.

In summary, these copper-based drugs may serve as potential therapeutic options for EC, either as monotherapies or in combination with standard chemotherapeutic agents. Nevertheless, further studies are required to comprehensively assess their efficacy, safety, and clinical applicability.

Conclusion and future perspectives

Emerging evidence confirms that cuproptosis is implicated in the pathophysiology of EC. Given the crucial role of copper ions in tumor proliferation, angiogenesis, and metastasis, copper-targeted therapy is emerging as an important new anti-cancer strategy. Currently, copper ionophores, chelators, and their combination therapies show promising results for EC treatment due to significant anti-tumor effects.

Multiple studies have successfully developed prognostic models for EC based on CRG, highlighting their potential as biomarkers for immunotherapy response. However, current research remains limited by the lack of systematic functional validation in vivo and in vitro, incomplete understanding of CRGs’ molecular mechanisms and signaling pathways, and insufficient clinical translation evidence. Thus, future research should focus on rigorously validating the functions of identified biomarkers; thoroughly investigating molecular mechanisms related to cuproptosis; and conducting preclinical and clinical translational studies.

Although copper-targeted therapy has limited effects in EC compared to other tumors, it still holds potential. Its clinical value of using copper-related biomarkers still requires further validation through large-scale multi-center studies. Additionally, developing combination therapy strategies based on copper metabolism regulation may enhance therapeutic efficacy against EC.

Abbreviations

AMPK

AMP activated protein kinase

ATOX1

Antioxidant 1 copper chaperone

ATP7A

ATPase copper transporting A

ATP7B

ATPase copper transporting B

BMI

Body mass index

CCS

Copper chaperone for superoxide dismutase

CDKN2A

Cyclin-dependent kinase inhibitor 2 A

COX17

Cytochrome oxidase copper chaperone 17

CRGs

Cuprotosis-related genes

CTR1

Copper transporter 1

DBT

Dihydrolipoamide branched chain transacylase E2

DLAT

Drolipoamide S-acetyltransferase

DLST

Dihydrolipoyllysine-residue succinyltransferase

DSF

Disulfiram

DSS

Disease-specific survival

EC

Endometrial cancer

ECM

Extracellular matrix

EGFR

Epidermal growth factor receptor

ES

Elesclomol

FDX1

Ferredoxin 1

FGF

Fibroblast growth factor

FGF

Fibroblast growth factor

GCS

Glycine cleavage system

GCSH

Glycine cleavage system H protein

GEO

Gene expression omnibus

GLS

Glutaminase

GO

Gene ontology

GSH

Glutathione

HIF-1

Hypoxia-inducible factor-1

IUDs

Intrauterine devices

KEGG

Kyoto encyclopedia of genes and genomes

KGDHC

α-ketoglutarate dehydrogenase complex

LIAS

Lipoic acid synthetase

LOX

Lactic oxidase

MAPK

Mitogen-activated protein kinase

MMP-9

Matrix metalloproteinase

MT 1/2

Metallothioneins 1 and 2

OS

Overall survival

PC

Pyruvate carboxylase

PCD

Programmed cell death

PDC

Pyruvate dehydrogenase complex

PDH

Pyruvate dehydrogenase

PDHA1

Pyruvate dehydrogenase E1 subunit alpha 1

PDHX

Pyruvate dehydrogenase complex component X

PD-L1

Programmed death ligand 1

PFI

Progression-free interval

POLRMT

Mitochondrial RNA polymerase

PPAT

Phosphoribosyl pyrophosphate amidotransferase

ROS

Reactive oxygen species

SLC31A1

Solute carrier family 31, member 1

SOD1

Superoxide dismutase 1

SUCLG1

Succinate-coA ligase GDP/ADP-forming subunit alpha

TCA

Tricarboxylic acid

TCGA

The cancer genome atlas database

TGN

Trans-Golgi network

TME

Tumor microenvironment

TRAF4

TNF receptor-associated factor 4

TTM

Tetrathiomolybdate

VEGF

Vascular endothelial growth factor

Author contributions

JXZ and WYS handled concept development and data curation. JY focused on concept creation and drafting the initial manuscript. HS worked on visualization. QPX contributed to review, editing, and oversight of the research. HKS was involved in reviewing, editing, project management, and funding applications. All authors have read and approved the final manuscript.

Funding

This study was funded by the Construction Fund of Key Medical Disciplines of Hangzhou (2025HZZD07). Zhejiang Province Medical and Health Science and Technology Program (2023KY933); Zhejiang Traditional Chinese Medicine Science and Technology Project (2023ZL565); Zhejiang Traditional Chinese Medicine Science and Technology Project (2022ZA139); Zhejiang Provincial Natural Science Foundation of China (LY21H040001).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.