Cuproptosis in gastric cancer: Mechanisms and therapeutic opportunities

Abstract

Gastric cancer remains one of the leading causes of cancer-related mortality, especially when disease recurrence, distant metastasis, and treatment resistance compromise long-term survival. Cuproptosis is a mitochondria-associated, copper-dependent mode of cell death that involves copper-induced clustering of lipoylated tricarboxylic acid cycle proteins, subsequent proteotoxic stress, and destabilization of iron-sulfur cluster proteins. This review summarizes the processes governing copper uptake, intracellular transport, buffering, and export, while outlining the molecular machinery that mediates cuproptosis. It further discusses the role of copper-dependent signaling in gastric cancer biology, with emphasis on receptor tyrosine kinase/mitogen-activated protein kinase pathways, the ubiquitin-proteasome system, autophagy, hypoxia signaling, angiogenesis, and the tumor microenvironment. It also addresses emerging therapies, including copper ionophores, copper chelators, and copper-based or copper-modulating nanoplatforms, and discusses biomarkers and actionable nodes, such as ferredoxin 1, amine oxidase copper-containing 1, integrin beta 1, and serpin family E member 1, which may help stratify patients and guide combinations with chemotherapy, targeted therapy, or immunotherapy. Understanding context-dependent mechanisms, therapeutic windows, and toxicity is essential for translating cuproptosis-based treatment strategies for gastric cancer.

Key Words: Cuproptosis; Copper metabolism; Gastric cancer; Tumor microenvironment; Immunotherapy; Copper ionophores; Copper chelators; Nanomedicine; Biomarkers

Core Tip: Cuproptosis connects copper imbalance with mitochondrial metabolic vulnerability, angiogenesis, immune regulation, and treatment resistance in gastric cancer. This review summarizes copper homeostasis, protein lipoylation, oncogenic signaling, the tumor microenvironment, and copper-modulating therapies. It highlights copper ionophores, chelators, nanomedicine, and biomarkers, including ferredoxin 1, amine oxidase copper-containing 1, integrin beta 1, and serpin family E member 1, for patient stratification and rational combination therapy while emphasizing toxicity and translational challenges.

INTRODUCTION

Gastric cancer (GC) is among the most common malignancies of the gastrointestinal tract. According to global cancer statistics, GC is ranked fifth worldwide for both disease incidence and cancer-related mortality[1]. Since GC at an early stage is often difficult to detect, many patients are diagnosed only after tumor progression has occurred. For individuals with advanced or metastatic GC, palliative systemic therapy is typically considered the primary therapeutic approach[2]. Current treatment commonly includes surgery combined with chemotherapy, targeted therapy, and other multidisciplinary strategies. However, outcomes for advanced GC remain unsatisfactory[3]. Conventional radiotherapy and chemotherapy have achieved only limited improvements, and multidrug resistance and recurrence reduce the effectiveness of standard regimens. Despite the application of targeted therapy, patients with metastatic disease achieve only a modest improvement in median overall survival (OS), with median OS extended by approximately 1 year[4,5].

With the growing understanding of the tumor microenvironment (TME), immunotherapy for advanced GC has progressed rapidly. Immune checkpoint inhibitors and other immunotherapeutic approaches have achieved breakthroughs in multiple malignancies and are increasingly used in clinical practice for GC. For advanced GC, immunotherapy mainly includes immune checkpoint blockade, adoptive cellular therapy, anti-vascular endothelial growth factor A antibody-based therapy, and tumor vaccine-based therapeutic strategies[6]. Of these modalities, therapeutic antibodies targeting the programmed death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway have demonstrated notable clinical efficacy in cancer treatment. Nevertheless, the clinical use of immunotherapy in GC remains constrained by variable target-antigen expression, inadequate T-cell infiltration within tumor tissues, and an immunosuppressive TME[7]. Therefore, identifying and developing novel therapeutic targets for GC, as well as constructing effective biomarkers and corresponding treatment strategies, are of great importance for precise diagnosis, individualized treatment, and prognostic assessment.

This review discusses copper metabolism and cuproptosis in GC from mechanistic and translational perspectives. It summarizes copper homeostasis, the molecular machinery of cuproptosis, cuproptosis-related signaling pathways, tumor microenvironmental regulation, emerging therapeutic strategies, and candidate biomarkers, with the aim of providing a reference for future experimental and clinical studies.

LITERATURE SEARCH STRATEGY

This narrative review was prepared through a systematic search of the literature in PubMed/MEDLINE, Web of Science, EMBASE, Scopus, and Google Scholar. Eligible publications available through May 17, 2026 were considered. The literature search was conducted by integrating Medical Subject Headings with appropriate free-text terms, such as “gastric cancer”, “stomach neoplasms”, “cuproptosis”, “copper metabolism”, “copper homeostasis”, “copper transporter”, “ferredoxin 1 (FDX1)”, “dihydrolipoamide S-acetyltransferase (DLAT)”, “lipoic acid synthetase (LIAS)”, “lipoyltransferase 1 (LIPT1)”, “dihydrolipoamide dehydrogenase (DLD)”, “ATPase copper-transporting alpha/beta (ATP7A/ATP7B)”, “solute carrier family 31 member 1 (SLC31A1)”, “tumor microenvironment”, “immunotherapy”, “copper ionophore”, “elesclomol”, “disulfiram”, “copper chelator”, “tetrathiomolybdate”, “nanomedicine”, and “biomarker”.

Articles were included if they addressed copper homeostasis, mechanisms of cuproptosis, GC biology, regulation of the TME, therapeutic strategies, or prognostic biomarkers. Articles were excluded if they were unrelated to GC or copper/cuproptosis biology, lacked mechanistic or translational relevance, were duplicates, or were not in English. No formal quantitative synthesis was performed, as this is a narrative review. Key studies were chosen for relevance, methodological quality, recency, and contribution to mechanistic or translational understanding.

COPPER METABOLISM

Copper is an indispensable trace element involved in numerous cellular processes, including copper-dependent enzymatic activity, cellular copper acquisition and distribution, autophagy-related kinase regulation, and metabolic cell-death signaling[8-10]. Copper exists mainly as monovalent Cu⁺ and divalent Cu²⁺. To preserve normal physiological activity, copper absorption, transport, utilization, and excretion are strictly controlled across the circulation, tissues, and individual cells[11]. Disruption of copper balance affects the central nervous system, liver, and lipid metabolism[12-14]. As shown in Figure 1, dietary copper is initially present as Cu²⁺. After copper reaches the intestinal epithelium, Cu²⁺ is reduced to Cu⁺ by reductases located on the epithelial surface, after which Cu⁺ enters cells through copper transporter 1. Within the cell, Cu⁺ is bound by ATOX1 (antioxidant 1 copper chaperone protein). ATPase copper-transporting beta (ATP7B) subsequently controls copper transport associated with the Golgi apparatus, thereby supporting copper incorporation into ceruloplasmin[15]. Beyond these physiological functions, copper also promotes angiogenesis and may participate in tumor initiation, progression, and metastatic dissemination by activating angiogenic factors[16]. Proangiogenic activity mediated by copper has been reported across various cancer types[17-20].

Figure 1 This schematic provides an overview of systemic copper metabolism and the regulation of copper homeostasis in humans. During intestinal absorption, copper predominantly exists in the divalent form, Cu²⁺, and is then reduced to monovalent Cu⁺ by membrane-bound reductases, including members of the STEAP protein family, prior to cellular entry. Cu⁺ enters cells mainly through copper transporter 1/solute carrier family 31 member 1. After cellular uptake, copper is distributed by intracellular chaperones, including antioxidant 1 copper chaperone and copper chaperone for superoxide dismutase. This intracellular delivery supports superoxide dismutase 1-mediated antioxidant protection and contributes to mitochondrial respiration through cytochrome c oxidase assembly factors such as COX11, SCO1, and COX17. When intracellular copper becomes excessive, it is sequestered by glutathione and metallothioneins. ATPase copper-transporting alpha/beta mediates copper export and controls Golgi-associated trafficking, allowing copper incorporation into secreted cuproproteins such as ceruloplasmin. Disruption of copper homeostasis may enhance pathological angiogenesis and participate in tumorigenesis, tumor expansion, and metastatic spread. ATOX1: Antioxidant 1 copper chaperone; CCS: Superoxide dismutase; SOD1: Superoxide dismutase 1; GSH: Glutathione; MT: Metallothioneins; ATP7A/ATP7B: ATPase copper-transporting alpha/beta; CTR1: Copper transporter 1; SLC31A1: Solute carrier family 31 member 1. Created by FigDraw (Supplementary material).

Abnormal copper metabolism denotes disrupted copper homeostasis, which may result in either copper deficiency or accumulation. Copper functions as a cofactor for many indispensable enzymes in nearly all living organisms[21]. To avoid the buildup of excess free copper, cells preserve intracellular copper concentrations at extremely low levels[16], as elevated copper abundance may induce copper-dependent cell death and may influence GC biology[22,23]. Increased copper levels have been widely reported in multiple malignancies, including breast cancer, head and neck cancer, and endometrial cancer[24,25]. These elevations are associated with cancer development, severity, and progression. Studies show that copper promotes tumor growth mainly by increasing cell proliferation, drug resistance, angiogenesis, and metastasis[16,26-29].

Copper acts as an essential cofactor for diverse enzymes and participates in numerous physiological processes. Nevertheless, abnormal changes in intracellular copper availability can induce oxidative stress and exert cytotoxic effects[16]. Copper homeostasis depends largely on the coordinated actions of transport proteins and intracellular chaperones. Representative molecules, including ATP7A and ATP7B, are essential for regulating copper balance because they mediate copper trafficking, intracellular distribution, and elimination in various tissues[30].

CUPROPTOSIS

As shown in Figure 2, cuproptosis is a distinct mitochondria-associated form of copper-dependent cell death that was first described by Tsvetkov et al[31]. Their study demonstrated that copper-mediated cytotoxicity differs mechanistically from apoptosis and other recognized forms of cell death. Specifically, elesclomol (ES)-copper remained cytotoxic in cells lacking the core apoptotic regulators BCL2-associated X apoptosis regulator and BCL2 antagonist/killer 1. In addition, pharmacological inhibitors of several known cell death pathways did not markedly attenuate this cytotoxic response. These findings collectively supported the identification of a previously unrecognized copper-dependent form of regulated cell death, subsequently termed cuproptosis. Further evidence suggested that ES-induced cell death is closely associated with mitochondrial oxidative respiration, because cells that depend heavily on respiratory metabolism are more vulnerable to copper ionophores than cells primarily relying on glycolysis. Mechanistically, copper induces DLAT oligomerization, promotes the formation of insoluble DLAT aggregates, triggers proteotoxic stress, and eventually results in cell death. Subsequent mechanistic analyses have further emphasized that FDX1 can reduce Cu²⁺ to Cu⁺, thereby linking copper redox conversion with lipoylation and aggregation of enzymes participating in the mitochondrial tricarboxylic acid (TCA) cycle[32]. Meanwhile, FDX1 also promotes the destabilization of iron-sulfur (Fe-S) cluster proteins, leading to mitochondrial stress responses that further support cuproptosis[33]. Accordingly, the accumulation of lipoylated DLAT aggregates and the loss of Fe-S cluster proteins are regarded as the major molecular features of cuproptosis[31,34]. Tsvetkov et al[31] also reported that the hydrophilic antioxidant glutathione (GSH) attenuates ES-Cu-mediated cytotoxicity by chelating intracellular copper. By contrast, other antioxidants, including N-acetylcysteine, α-tocopherol, ebselen, and JP4-039, were unable to rescue ES-Cu-induced growth suppression. These observations indicate that reactive oxygen species (ROS), including mitochondria-derived ROS, are not indispensable mediators of cuproptosis. Overall, cuproptosis represents a mitochondria-associated mode of cell death that depends on copper but occurs independently of oxidative stress.

Figure 2 Proposed model of cuproptosis. Cuproptosis refers to a mitochondria-related, copper-dependent form of regulated cell death. Elesclomol, acting as a copper ionophore, facilitates intracellular copper accumulation, whereas ferredoxin 1 catalyzes the conversion of Cu²⁺ into Cu⁺. Increased Cu⁺ levels enhance lipoylation-dependent interactions and drive the aggregation of lipoylated proteins associated with the tricarboxylic acid cycle, especially dihydrolipoamide S-acetyltransferase (DLAT), thereby triggering proteotoxic stress. At the same time, copper-mediated stress impairs the stability of iron-sulfur (Fe-S) cluster proteins and accelerates their depletion, which in turn activates mitochondrial stress responses. Collectively, the accumulation of aggregated lipoylated DLAT together with the loss of Fe-S cluster proteins represents a defining molecular hallmark of cuproptosis. This mode of cell death is independent of reactive oxygen species and generally cannot be blocked by antioxidants, except for glutathione, which attenuates cuproptosis through copper chelation. ES: Elesclomol; FDX1: Ferredoxin 1; TCA: Tricarboxylic acid; DLAT: Dihydrolipoamide S-acetyltransferase; Fe-S: Iron-sulfur; ROS: Reactive oxygen species; GSH: Glutathione. Created by FigDraw (Supplementary material).

Subsequently, Tsvetkov et al[31] performed a CRISPR-Cas9 loss-of-function screen and identified seven genes linked to cuproptosis, with FDX1 being defined as the sole driver of this process. The other six genes may be grouped on the basis of their biological roles. Lipoic acid (LA) pathway genes, including LIPT1, LIAS, and DLD, are involved in LA metabolism. By comparison, genes associated with lipoylation, such as DLAT, pyruvate dehydrogenase E1 subunit alpha 1 (PDHA1), and pyruvate dehydrogenase E1 subunit beta (PDHB), control protein lipoylation, a process essential for cuproptosis. In addition, cuproptosis-related genes also include negative regulatory factors and copper transport molecules. MTF1, GLS, and CDKN2A act as anti-cuproptotic genes that inhibit this cell death program, whereas ATP7A, ATP7B, and SLC31A1 serve as copper transporters that regulate intracellular copper distribution and trafficking[31].

FDX proteins are members of the small Fe-S protein family and are involved in a wide range of metabolic activities[35]. FDX1 has been shown to participate in the regulation of cuproptosis[36]. In the LA pathway, FDX1 functions as an important regulator of protein lipoylation[31]. It also contributes to the control of glucose metabolism, fatty acid oxidation, and amino acid metabolism, which may partly explain its prognostic significance in lung adenocarcinoma[37]. Relative to paired nontumorous tissues, FDX1 expression is increased in glioblastoma and malignancies of the female reproductive system, but decreased in several solid tumors, including lung adenocarcinoma and hepatocellular carcinoma[38]. High FDX1 expression has been associated with unfavorable prognosis in head and neck squamous cell carcinoma and low-grade glioma. In contrast, elevated FDX1 levels appear to correlate with improved clinical outcomes in cervical squamous cell carcinoma and clear cell renal cell carcinoma[38-40]. In clear cell renal cell carcinoma, increased expression of FDX1 and DLAT is related to superior survival, whereas CDKN2A appears to exert oncogenic effects, with its overexpression predicting poorer survival[41]. One possible explanation is that FDX1 and CDKN2A contribute to the regulation of immune cell infiltration across different cancer types[42].

LA synthase (LIAS), a member of the biotin-LA synthase family, mediates the terminal step in LA biosynthesis[43]. These findings suggest that LIAS could serve as a promising therapeutic target in cancers that rely heavily on mitochondrial oxidative respiration. More broadly, a cuproptosis-related human copper-proteome signature has been associated with prognosis, immune infiltration, and predicted immunotherapy response in GC[44].

DLAT can increase enzyme activity, promote nucleic acid synthesis, and facilitate cancer cell growth[45]. At present, DLAT, LIPT1, and LIAS are recognized as three cuproptosis-related genes with potential value as diagnostic biomarkers for pancreatic adenocarcinoma[46]. Earlier investigations have shown that DLAT expression is elevated in GC cells, indicating that DLAT may represent a promising mitochondrial therapeutic target in GC[47].

Cell metabolism is closely associated with tumor progression[48]. Liu et al[49] reported that the miR-21-5p/PDHA1 axis contributes to the regulation of glycolysis and the advancement of GC. In addition, Song et al[50] found that PDHA1 mRNA levels were decreased across several GC histological subtypes, including intestinal, diffuse, and mixed forms. Kaplan-Meier survival analysis also revealed a significant association between low PDHA1 expression and poor OS in patients with GC. In addition, PDHA1 overexpression in hepatocellular carcinoma has been shown to modulate TCA enzyme activity, suppress aerobic glycolysis, and strengthen mitochondrial apoptosis-related signaling[51].

ATP7A and ATP7B are highly homologous proteins belonging to the copper-transporting ATPase family. When intracellular copper levels exceed physiological requirements, ATP7A mediates copper efflux toward the extracellular compartment, whereas ATP7B promotes copper secretion from hepatocytes into the bile. Pathogenic changes in ATP7A or ATP7B may impair copper metabolism and cause neurological damage, eventually resulting in Menkes disease and Wilson disease, respectively[11]. Recent findings indicate that ATP7A is abundantly expressed on the membrane of KRAS-mutant colorectal cancer cells, where it protects against toxicity caused by excessive copper ions[52]. Moreover, ATP7A is able to interact with vascular endothelial growth factor receptor 2 (VEGFR2), suppressing VEGFR2 degradation and promoting angiogenesis through the p62-SQSTM1 pathway[53]. Taken together, these findings suggest that ATP7A may indirectly promote angiogenesis, thereby facilitating tumorigenesis and disease progression.

Notably, ATP7A and ATP7B are also capable of binding platinum-based drugs and promoting their efflux from cancer cells, thereby facilitating the development of chemotherapy resistance. ATP7B has been implicated in resistance to platinum-based chemotherapy across various malignancies, such as ovarian cancer[54] and head and neck cancer[55]. Furthermore, knockout of ATP7A in breast cancer cells substantially enhances the suppressive effect of cisplatin on cellular proliferation[56]. Collectively, these observations indicate that ATP7A and ATP7B could represent promising therapeutic targets in cancer treatment. Inhibition of ATP7A or ATP7B could reduce tumor angiogenesis and improve the antitumor activity of platinum-based agents.

MECHANISMS OF CUPROPTOSIS IN GC

Receptor tyrosine kinase signaling pathway

Previous studies have shown that copper is critically involved in receptor tyrosine kinase (RTK)-related signaling. Copper may activate RTKs independently of ligand binding by epidermal growth factor or hepatocyte growth factor. Once activated, epidermal growth factor receptor and mesenchymal-epithelial transition factor promote phosphorylation of downstream extracellular signal-regulated kinase and protein kinase B (AKT), thereby enhancing cell migration and proliferation[57]. Copper ions may also support AKT activation by modulating phosphoinositide 3-kinase (PI3K) or phosphoinositide-dependent kinase 1[58]. In gastric adenocarcinoma, activation of RTK/RAS signaling induces a stem-like phenotype that is closely linked to metastasis and resistance to chemotherapy[59].

Mitogen-activated protein kinase signaling pathway

The mitogen-activated protein kinase (MAPK) signaling pathway is also subject to regulation by copper ions. Specifically, copper can interact with MAPK kinase 1, enhance extracellular signal-regulated kinase 1/2 phosphorylation, and stimulate c-Jun N-terminal kinase activation, thereby supporting tumor progression[60]. Liu et al[61] further showed that disulfiram/copper (DSF/Cu) increases ROS production in GC cells and induces a cell death-associated MAPK signaling response.

Ubiquitin-proteasome system

Although the ubiquitin-proteasome system (UPS) broadly regulates intracellular protein degradation, GC-specific analyses have linked UPS-related expression patterns with distinct molecular subtypes, molecular characteristics, and patient prognosis[62]. This system is strongly implicated in various biological processes related to tumor progression, such as cancer cell proliferation, programmed cell death, neovascularization, and metastatic spread. Notably, Cu²⁺ has been reported to directly interact with proteasomal components, thereby suppressing proteasome activity[63]. Diethyldithiocarbamate can chelate Cu⁺ to generate a binuclear copper-containing complex, such as DDTCCu⁺. This complex suppresses tumor cell proliferation and proteasomal function by promoting the accumulation of ubiquitinated proteins, upregulating p27 expression, and inhibiting nuclear factor kappa B (NF-κB) activity. NF-κB is a crucial transcription factor that participates in controlling cell proliferation, invasion, metastatic dissemination, and angiogenesis[64]. Earlier studies have shown that DSF/Cu inhibits GC cell growth by regulating stress-response mechanisms and modulating the Wnt/β-catenin/NF-κB signaling pathway[65].

Autophagy

Autophagy breaks down and recycles cellular components. It enhances the capacity of malignant cells to tolerate adverse stimuli, including oxygen deprivation, genomic injury, and chemotherapeutic exposure. It also supports tumor metabolic activity and proliferative growth, thereby contributing to cancer progression[66]. In GC, autophagy is closely linked to chemoresistance, and key autophagy-related proteins and noncoding RNAs may regulate therapeutic response and provide potential intervention targets[67]. Similar to the MAPK pathway, autophagy supports the preservation of cancer cell survival and may be directly modulated by copper ions[8].

Hypoxia-inducible factor 1α-related signaling pathway

Hypoxia is an important microenvironmental factor regulating tumor angiogenesis. The key transcription factor for cellular adaptation to hypoxia is hypoxia-inducible factor 1α (HIF-1α)[68]. Numerous reports show that copper ions exhibit proangiogenic properties that depend on their interactions with HIF-1α-related signaling pathways[69]. Li et al[70] summarized HIF-1α-related mechanisms in GC, including proliferation, apoptosis, angiogenesis, epithelial-mesenchymal transition (EMT), and drug resistance, and proposed HIF-1α signaling as a potential therapeutic target. In a separate study, A-kinase-interacting protein 1 was reported to promote GC cell invasion and stem-like properties under hypoxic conditions through activation of HIF-1α and β-catenin signaling pathways[71].

Angiogenesis

Copper has been reported to regulate multiple pro-angiogenic mediators, including interleukin-8, interleukin-6, interleukin-1, tumor necrosis factor-alpha, superoxide dismutase 1, and fibroblast growth factor 2[72]. Malignant angiogenesis facilitates cancer cell proliferation, dissemination, and invasion, as neovascularization occurs during the initial phases of tumor development[73]. Copper stimulates angiogenesis by promoting endothelial cell movement, growth, and fibronectin production[74]. Angiogenesis in GC is dynamically linked to tumor progression and has potential therapeutic relevance[75]. Copper depletion can suppress angiogenesis and inhibit endothelial cell proliferation. Copper-depletion strategies have therefore been proposed as a way to inhibit cancer-associated angiogenesis[16]. Tetrathiomolybdate suppresses tumor-associated angiogenesis primarily by chelating copper ions and generating poorly soluble copper-containing complexes[13]. Studies show that abnormal angiogenesis helps tumors grow and allows GC cells to invade and spread[76]. As a result, antiangiogenic therapy is now a major therapeutic focus for GC management and disease control[77].

CUPROPTOSIS-BASED THERAPEUTIC STRATEGIES FOR GC

Although many new strategies for GC have emerged in recent years, chemotherapy remains important. Platinum-containing agents, including cisplatin, oxaliplatin, and carboplatin, remain the principal therapeutic options. Drug resistance remains the primary challenge and often causes treatment failure, especially when tumors metastasize[78,79]. The development of novel targeted therapies has reshaped cancer treatment strategies and marked the beginning of the precision medicine era. Copper plays a critical role in tumorigenesis, and growing evidence suggests that copper complex-based compounds exert cytotoxic activity against drug-resistant cancer cells[80-82]. Copper ionophores and chelators also show promise for targeted therapy. Furthermore, nanomedicines for precision treatment have been developed.

Tables 1 and 2 summarize current copper-modulating therapeutic strategies, representative agents, evidence levels, and translational challenges[83-97].

Table 1 Representative agents/platforms and proposed mechanisms.

Strategy	Representative agents/platforms and evidence	Proposed mechanism
Copper ionophores	Elesclomol; disulfiram/copper (DSF/Cu); cisplatin plus disulfiram for advanced gastric cancer (NCT05667415; not yet recruiting; no results posted)[83-86]	Increase intracellular copper, promote mitochondrial stress, induce cuproptosis-related or ROS-dependent cytotoxicity, and enhance chemotherapy response[31,61,83,84,86]
Copper chelators	Tetrathiomolybdate, D-penicillamine, triethylenetetramine/tetraethylenepentamine[87-89]	Reduce copper bioavailability, inhibit copper-driven angiogenesis, and may modulate immune checkpoint signaling and tumor vascularization[16,87-89]
Copper-based or copper-modulating nanomedicine	CuO nanoparticles, elesclomol-loaded copper oxide nanoplatforms, CuMoO4-based systems, mitochondria-targeted copper-depleting nanoparticles[90-96]	Improve tumor-targeted copper delivery or depletion, induce mitochondrial stress/cuproptosis, and enable combination with photothermal therapy, chemotherapy, or immunotherapy[90-96]
Combination therapy	Copper modulation plus chemotherapy, immune checkpoint blockade, targeted therapy, or photothermal therapy[17,88,90,94,95]	May overcome drug resistance, reshape the tumor microenvironment, and convert immunologically cold tumors into more responsive phenotypes[17,88,90,93,95]

Copper-modulating therapeutic strategies and translational challenges in gastric cancer. ROS: Reactive oxygen species.

Table 2 Evidence level and translational limitations.

Strategy	Current evidence level	Main limitations
Copper ionophores	Gastric cancer-specific preclinical evidence; registered disulfiram/cisplatin gastric cancer trial is exploratory and has no posted results[61,85,86,90,97]	Narrow window, systemic toxicity, unclear patient selection, no mature gastric cancer efficacy data, and context-dependent mitochondrial metabolism[84-86]
Copper chelators	Mostly preclinical or early clinical evidence in non-GC malignancies; direct GC-specific clinical evidence remains limited[87,88]	Non-selective systemic copper depletion, potential neurological/hematological toxicity, and uncertain optimal combination schedules[87-89]
Copper-based or copper-modulating nanomedicine	Predominantly preclinical evidence in tumor models, with limited gastric cancer-specific validation[90-96]	Biodistribution, long-term safety, manufacturing reproducibility, and regulatory translation remain unresolved[89,91,93,95]
Combination therapy	Strong mechanistic rationale, but prospective biomarker-guided gastric cancer trials are still needed; clinical exploration remains limited[85,86,95]	Requires validated biomarkers, toxicity monitoring, dose optimization, and careful sequencing of treatment modalities[86,88,95]

Copper-modulating therapeutic strategies and translational challenges in gastric cancer. GC: Gastric cancer.

Copper ionophores

Copper ionophores are small-molecule compounds that facilitate the movement of extracellular copper ions through cellular membranes, resulting in increased intracellular copper accumulation. These agents are capable of triggering cuproptosis[83,84]. Representative examples include ES and disulfiram (DSF). In cancer therapy, ES primarily acts on mitochondria and exhibits potent inhibitory effects against cancer stem-like cells, chemoresistant cell populations, and tumor cells with limited glycolytic dependence. Prolonged ES exposure has been shown to elevate TCA cycle-related metabolites in non-small cell lung cancer cells, indicating that cuproptosis may directly affect TCA cycle metabolism[85]. In a bladder cancer mouse model, the combination of ES and an anti-PD-L1 antibody promoted cuproptosis and enhanced the efficacy of cancer immunotherapy[90]. Studies of DSF in tumors have increased in recent years. The DSF/Cu complex has been reported to exert cytotoxic effects and induce S-phase arrest in cervical cancer cells, including LGR5-positive cancer stem-like cells[98]. DSF/Cu enhances ROS generation and promotes ROS-dependent apoptosis. In addition, DSF induces oxidative stress via the ROS/MAPK and nuclear protein localization protein 4 pathways, leading to copper-dependent apoptosis in GC cells[65].

Copper chelators

Copper chelators decrease copper bioavailability through direct binding to copper ions. Studies show that copper chelators inhibit tumor growth in animal models, making them potential anticancer agents[87]. In addition to findings from preclinical studies, clinical trials have investigated copper-chelating agents in malignancies with increased copper deposition. As an early identified copper-chelating compound, tetrathiomolybdate has been demonstrated to suppress lung metastasis in head and neck tumors and breast cancer, largely through inhibition of lysyl oxidase activity[88]. Moreover, GSH functions as an endogenous intracellular chelator of copper ions. Depletion of GSH elevates copper accumulation within cells and subsequently induces cell death[31]. Copper chelators reported to exhibit anticancer activity include D-penicillamine, tetrathiomolybdate, and tetraethylenepentamine[87-89]. Copper chelators also exhibit synergistic effects with immune checkpoint inhibitors. Current evidence indicates that copper chelation facilitates PD-L1 degradation, enhances the infiltration of CD4+ and CD8+ lymphocytes into tumor tissues, and stimulates natural killer (NK) cell activity[89]. However, copper chelators pose toxicity risks due to their nonselective copper depletion, which can affect normal cells and potentially cause harm, such as organ dysfunction or hematologic abnormalities. Therefore, precise targeted delivery is important.

Nanomaterials

These platforms enable accurate cancer cell targeting while limiting injury to normal cells[91]. Because of their high surface-area-to-volume ratio and flexible payload design, copper- or metal-based nanoplatforms can interact efficiently with tumor cells and enable controlled intracellular release of therapeutic components. In GC models, a ZnO@DNAzyme-Cu(II)-ES nanoplatform was reported to suppress ATP7B, deliver copper/ES, and promote copper-induced cancer-cell death[92]. Copper oxide-based nanoparticles can also promote ROS generation, thereby damaging lipids, proteins, DNA structures, and mitochondrial function[93]. ES and Cu released from ES-copper-loaded nanoparticles (NP@ESCu) induce cuproptosis and an immune response[90], and stimulus-responsive copper complex nanoparticles have similarly been reported to induce cuproptosis and augment cancer immunotherapy[94]. Experimental studies have shown that copper oxide-based nanoparticles can induce antitumor effects in breast and prostate cancer models[93,99]. Combining CuO nanoparticles with NP@ESCu could enhance antitumor efficacy. Zhou et al[100] used Au@MSN-Cu/PEG/DSF together with photothermal therapy, which effectively promoted tumor cell death and inhibited tumor growth. Zhang et al[96] found that CuMoO4 induces cuproptosis and may serve as a promising nanocarrier. Copper-depleting nanoparticles have been shown to reprogram tumor metabolism and inhibit disease progression in murine models of triple-negative breast cancer[95]. Nanomaterials enable targeted treatment and hold broad promise for GC therapy.

Currently, most evidence for cuproptosis-based therapies in GC is preclinical, and clinical data are insufficient for routine use. At the clinical level, the clearly GC-specific registered copper-modulating drug trial identified in this review is cisplatin plus disulfiram for advanced GC (ClinicalTrials.gov identifier: NCT05667415), but no efficacy results have been reported; therefore, this trial should be interpreted as clinical exploration rather than evidence of established benefit[86]. Future investigations should further distinguish direct cuproptosis from other copper-associated cytotoxic events. In addition, canonical markers, including FDX1 activity, DLAT aggregation, lipoylated protein accumulation, and Fe-S cluster protein depletion, require further rigorous validation[101]. It is also necessary to assess whether copper-modulating compounds can be safely integrated with chemotherapy, targeted therapy, or immunotherapy in molecularly defined GC subgroups.

GC MICROENVIRONMENT AND IMMUNOTHERAPY

The TME comprises malignant cells together with adjacent nonmalignant components, such as stromal elements and diverse immune cell populations. It mainly consists of cancer-associated fibroblasts (CAFs), infiltrating immune cell subsets, tumor-associated vascular endothelial cells, and components of the extracellular matrix[102]. The TME is pivotal for immunotherapeutic efficacy because it provides multiple regulatory targets for tumor progression.

Studies have demonstrated that increased CAF abundance correlates with metastasis and poor prognosis in GC[103,104]. Moreover, Helicobacter pylori, a recognized risk factor for GC, accelerates its progression by upregulating PIEZO1 and enhancing CAF infiltration[105]. The GC immune microenvironment is composed of diverse immune cell populations, including tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), and tumor-infiltrating lymphocytes (TILs). High CX3CR1 expression on TAMs and MDSCs induces acute inflammation and facilitates tumor progression[106]. PD-1 signaling has also been shown to promote tumor-infiltrating MDSCs and gastric tumorigenesis in mice[107]. Within TIL populations, regulatory T cells suppress anticancer immune responses[108]. Angiogenesis-related endothelial activity also contributes to tumor progression and neovascularization[109].

Currently, there are two common immunotherapeutic approaches for GC. One strategy aims to strengthen endogenous antitumor immunity by suppressing inhibitory immune checkpoint pathways within the TME, a mechanism exemplified by immune checkpoint inhibitor therapy. Another strategy relies on the ex vivo expansion and genetic or functional modification of selected immune cells to enhance their tumor-killing capacity, followed by reinfusion into the patient, as represented by adoptive cell therapy (ACT).

In GC, the binding of PD-1 to PD-L1 promotes dysfunction of T cells, making this pathway a key target for immunotherapeutic intervention. PD-L1 expression is elevated in patients with GC and is linked to advanced stage, larger tumor size, aggressive behavior, distant metastasis, and poor OS[110]. CAF-derived IL-8 can upregulate PD-L1 expression in GC through the NF-κB pathway, potentially contributing to immune escape[111]. TAM infiltration, especially M2-like macrophage infiltration, has been shown to be highly associated with PD-L1 expression in gastric adenocarcinoma, supporting macrophage involvement in immunoregulatory networks within the TME[112]. Preclinical GC studies suggest that combined anti-CTLA-4 and anti-PD-1 treatment can suppress proliferation, migration, invasion, and EMT-related signaling in GC cells[113]. Cadonilimab mediates simultaneous blockade of PD-1 and CTLA-4. In patients with previously untreated human epidermal growth factor receptor 2 (HER2)-negative, locally advanced or metastatic GC, cadonilimab combined with chemotherapy has been reported to improve survival compared with chemotherapy alone[114]. Following PD-L1 and CTLA-4, lymphocyte activation gene 3 (LAG-3) has emerged as a potential immunotherapeutic target. LAG-3 suppresses antitumor immunity by promoting T-cell apoptosis and limiting T-cell proliferation[115]. Few clinical studies have examined LAG-3, so its therapeutic potential warrants further exploration.

ACT produces antitumor activity by expanding and engineering patient-derived autologous immune cells ex vivo. These modified immune cells can express newly introduced receptors, including chimeric antigen receptors (CARs)[116]. CAR-T strategies have been reviewed across multiple GC targets, including HER2, carcinoembryonic antigen, mucin 1, epithelial cell adhesion molecule, claudin 18.2, mesothelin, natural-killer receptor group 2 member D, and folate receptor 1[117]. Nevertheless, ACT use in solid tumors, including GC, is still restricted by multiple challenges. These include target-antigen heterogeneity, inadequate infiltration of T cells into tumor tissues, and immunosuppressive mechanisms driven by the TME[118]. Further studies are needed to advance ACT for GC.

POTENTIAL TARGETS OF CUPROPTOSIS IN GC

Copper-modulating approaches can inhibit GC growth and induce antitumor activity[61,119]. In GC patients, copper concentrations in serum and tumor tissues are markedly elevated relative to those detected in noncancerous gastric specimens[83]. Elevated copper concentrations have been linked to GC progression and may be particularly relevant in mucinous adenocarcinoma with high copper content[83,97]. In GC tissues, most cuproptosis-related genes are upregulated and display relatively frequent mutational alterations. Among these genes, LIAS and FDX1 appear to be strongly linked to survival outcomes in patients with GC[120,121]. These findings suggest that cuproptosis participates in GC progression, and that its molecular mechanisms and associated targets may hold potential value for GC diagnosis, therapeutic intervention, and prognostic evaluation.

Tables 3 and 4 summarize the major cuproptosis-related pathways and candidate biomarkers discussed in this review[122-132].

Table 3 Biological roles.

Pathway/biomarker	Role in copper metabolism or cuproptosis
FDX1	Reduces Cu2+ to Cu+ and promotes lipoylation-dependent aggregation of TCA-cycle proteins, especially DLAT[31-33,97,122]
DLAT/LIAS/LIPT1/DLD (lipoylation-related genes)	Core components of mitochondrial protein lipoylation and lipoylated TCA-cycle protein aggregation during cuproptosis[31,34,43,47]
SLC31A1/ATP7A/ATP7B (copper transporters)	Regulate copper uptake and efflux; ATP7A/ATP7B can also influence platinum-drug transport and chemoresistance[11,16,30,52-56]
AOC1	Copper-containing amine oxidase involved in polyamine catabolism and ROS-related metabolic stress[123,124]
ITGB1	Integrin-mediated regulator of cell adhesion, metabolism, migration, and cuproptosis-related phenotypes[125,126]
SERPINE1	Regulates extracellular matrix remodeling, EMT, angiogenesis, apoptosis, and immune infiltration[127-130]

Cuproptosis-related pathways and candidate biomarkers in gastric cancer. FDX1: Ferredoxin 1; TCA: Tricarboxylic acid; DLAT: Dihydrolipoamide S-acetyltransferase; LIAS: Lipoic acid synthetase; LIPT1: Lipoyltransferase 1; DLD: Dihydrolipoamide dehydrogenase; ATP7A/ATP7B: ATPase copper-transporting alpha/bet; SLC31A1: Solute carrier family 31 member 1; AOC1: Amine oxidase copper-containing 1; ROS: Reactive oxygen species; EMT: Epithelial-mesenchymal transition; SERPINE1: Serpin family E member 1; ITGB1: Integrin β1.

Table 4 Gastric cancer evidence and clinical implications.

Pathway/biomarker	Evidence in gastric cancer	Potential clinical implication
FDX1	Linked to cuproptosis sensitivity, copper-lactylation signaling, and immune infiltration in gastric cancer-related studies[97,121,122,131,132]	Candidate marker for cuproptosis susceptibility and rational selection of copper-modulating strategies[97,121,122,131,132]
DLAT/LIAS/LIPT1/DLD (lipoylation-related genes)	Altered expression of lipoylation-related genes has been associated with gastric cancer metabolism and prognosis[47,49-50,122]	May help define tumors with mitochondrial metabolic dependence and potential vulnerability to cuproptosis induction[31,47,122]
SLC31A1/ATP7A/ATP7B (copper transporters)	Copper transporter dysregulation may affect intracellular copper accumulation, angiogenesis, and response to platinum-based therapy[16,52-56]	Potential targets to enhance copper-mediated cytotoxicity or overcome chemotherapy resistance[52-56]
AOC1	AOC1 down-regulation suppresses AKT signaling, epithelial-mesenchymal transition, proliferation, invasion, and migration in gastric cancer cells[124]	Candidate therapeutic and prognostic biomarker linked to tumor growth and metastasis[124]
ITGB1	High ITGB1 expression is associated with poor prognosis in diffuse gastric cancer and may reduce sensitivity to copper ionophores[125,126]	Potential stratification marker and actionable node for enhancing cuproptosis-based therapy[125,126]
SERPINE1	Elevated SERPINE1 expression in gastric adenocarcinoma is associated with proliferation, migration, and immunosuppressive features[128-130]	Candidate prognostic and immune-related marker that may guide combination strategies[128-130]

Cuproptosis-related pathways and candidate biomarkers in gastric cancer. FDX1: Ferredoxin 1; DLAT: Dihydrolipoamide S-acetyltransferase; LIAS: Lipoic acid synthetase; LIPT1: Lipoyltransferase 1; DLD: Dihydrolipoamide dehydrogenase; ATP7A/ATP7B: ATPase copper-transporting alpha/bet; SLC31A1: Solute carrier family 31 member 1; AOC1: Amine oxidase copper-containing 1; SERPINE1: Serpin family E member 1; ITGB1: Integrin β1.

FDX1

FDX1 promotes the conversion of Cu²⁺ to the more cytotoxic Cu⁺ state, especially under conditions of increased intracellular copper accumulation[97]. Sun et al[97] reported that elevated copper concentrations enhance lactylation at METTL16-K229. Subsequently, lactylated METTL16 upregulates FDX1 mRNA and protein levels through N6-methyladenosine modification, ultimately inducing lipoylation of DLAT and cuproptosis in GC tissues. The METTL16-FDX1-cuproptosis pathway mediated by copper-dependent lactylation represents a critical regulatory mechanism in copper-associated metabolic processes. Mitochondrial uncoupling has also been reported to sensitize GC cells to ES-induced cuproptosis via FDX1/DLAT upregulation[122]. A recent bioinformatics study found that cuproptosis-related regulatory axes may be associated with stomach adenocarcinoma (STAD) progression[131]. Previous studies have demonstrated that the long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) promotes proliferation, migration, and invasion in STAD cells. MALAT1 has further been implicated in cisplatin resistance in STAD[133]. Notably, FDX1-focused analyses and cuproptosis-signature studies show associations with immune-cell infiltration and TME characteristics, indicating that cuproptosis may serve not only as a potential therapeutic target in GC but also as an important mediator of tumor immune regulation[121,132,134,135]. Therefore, FDX1 may influence GC growth and could be therapeutically targetable, although direct evidence for selective FDX1 inhibitors in GC remains limited.

Amine oxidase copper-containing 1

Polyamine metabolism is closely linked to GC biology and may influence gastric epithelial and immune-cell functions during Helicobacter pylori-associated inflammation and tumor progression[136]. Amine oxidase copper-containing 1 (AOC1) is a copper-containing diamine oxidase involved in the metabolism of histamine and diamines, and this enzymatic context supports its biological link with polyamine catabolism[123]. Evidence from earlier research suggests that AOC1 knockdown suppresses AKT pathway activity and EMT, thereby impairing the proliferation, invasion, and migration of human-derived GC cells; accordingly, AOC1 may represent a potential therapeutic target[124].

Integrin β1

Integrin β1 (ITGB1) is an important member of the integrin family. Previous research has suggested that ITGB1 functions as an oncogenic factor and modulates the proliferation, migration, and invasion of diffuse GC (DGC) cells[125,126]. Western blot analysis further demonstrated a close relationship between ITGB1 and cuproptosis-related genes, including FDX1, LIAS, DLD, DLST, DLAT, PDHA1, and PDHB. In addition, ITGB1 downregulation inhibits cell proliferation and migration while enhancing cellular sensitivity to copper ionophores. Single-sample gene set enrichment analysis showed that reduced ITGB1 expression was accompanied by higher cuproptosis scores and was inversely correlated with major cuproptosis regulators, such as FDX1, DLAT, and DLST. Functional enrichment analysis further suggested that ITGB1 may be involved in regulating tumor-associated metabolic pathways and immune responses. Integrated transcriptomic and proteomic analyses indicated that elevated ITGB1 expression is strongly associated with unfavorable clinical outcomes in DGC. Further investigation revealed a potential link between ITGB1 dysregulation and mutational signatures related to impaired DNA mismatch repair. Therefore, modulating ITGB1 overexpression may help regulate DGC progression by triggering cuproptosis-related vulnerability[126].

SERPINE1

SERPINE1 belongs to the serine protease inhibitor family and functions as the major endogenous inhibitor of tissue plasminogen activator and urokinase-type plasminogen activator. Several GC-specific studies have linked SERPINE1 to EMT, malignant progression, poor prognosis, cuproptosis-related genes, and immune infiltration[127-130]. In gastric adenocarcinoma, SERPINE1 is reported to be elevated and to enhance tumor cell invasion and proliferation by regulating EMT[129]. One study reported that SERPINE1 was inversely associated with several cuproptosis-related genes, including FDX1, LIAS, LIPT1, and PDHA1. Immune infiltration analysis further indicated that SERPINE1 displays distinct expression characteristics in GC tissues. Functional evaluation linked SERPINE1 to angiogenesis, apoptosis, and extracellular matrix degradation. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis suggested that SERPINE1 may be involved in multiple signaling networks, including the tumor protein p53, PI3K/AKT, and transforming growth factor-beta pathways. Additional immune-related analyses showed that SERPINE1 expression was positively associated with infiltration of resting NK cells, neutrophils, activated mast cells, and M2 macrophages, but negatively correlated with memory B cells and plasma cells[130]. Taken together, these results indicate that SERPINE1 may enhance GC cell growth and motility while reducing active immune cell infiltration and protecting tumor cells from apoptosis. Accordingly, SERPINE1 may represent a promising therapeutic target for GC.

DISCUSSION

GC remains a major challenge. Surgery is the only curative option for localized disease, yet recurrence and metastasis are frequent. Outcomes for advanced GC remain unsatisfactory, highlighting the need to clarify mechanisms underlying tumor progression and treatment resistance and to identify new therapeutic targets. In this review, we summarize the physiological roles of copper, discuss the contribution of copper dyshomeostasis to mitochondrial stress and regulated cell death, and further consider copper metabolism, cuproptosis-associated signaling pathways, immune-microenvironment interactions, copper-modulating strategies, and candidate prognostic biomarkers in GC.

Although radiotherapy, chemotherapy, and targeted therapy have improved some outcomes, progress in advanced GC remains limited, and median OS remains unsatisfactory. Beyond conventional therapeutic modalities such as surgical resection, radiotherapy, chemotherapy, and molecularly targeted treatment, immunotherapy has become an increasingly prominent approach in cancer management. Cuproptosis may be linked to malignant progression and the tumor immune microenvironment, thereby affecting prognosis and immunotherapy response. Tumors with low immune activity in the TME are often considered immunologically cold, whereas those with high immune activity are considered immunologically hot. Immune-hot tumors are more likely to respond to T-cell-targeted immunotherapy or related approaches, whereas immune-cold tumors are harder to treat because of low T-cell infiltration. One potential strategy is to convert cold tumors into hot tumors before applying additional therapies. In the future, GC treatment may benefit from rational combinations of immunotherapy with other modalities.

During recent decades, advances in targeted therapy have facilitated new treatment strategies for GC. Inducing cuproptosis has attracted increasing interest as a promising approach for overcoming therapeutic resistance. Several pharmacological agents can modulate intracellular copper ion levels, including copper ionophores and copper-chelating compounds such as triethylenetetramine dihydrochloride and penicillamine. These agents may alter intracellular copper availability and thereby modulate cuproptosis.

Precision treatment of GC may benefit from novel nanomaterials. In future applications, nanomaterials may be functionalized with specific recognition molecules to selectively identify GC cells and achieve targeted therapeutic effects. Nanomaterials also serve as drug carriers, efficiently delivering chemotherapeutic drugs, gene-therapy drugs, and other agents to cancer cells. Controlled drug release and dosing may maintain continuous, effective treatment while reducing side effects. Nanomaterials can be combined with treatments such as photothermal therapy and immunotherapy to develop multimodal strategies. This approach leverages the advantages of nanomaterial targeting and immunotherapy, potentially improving treatment outcomes and patient prognosis. Nevertheless, additional investigations are required to improve the preparation procedures, biocompatibility, and safety profiles of these approaches, thereby enhancing their therapeutic applicability in GC.

Despite growing interest in cuproptosis-based therapy, clinical translation in GC faces several key challenges. Regulatory mechanisms and signaling pathways remain incompletely understood, and most supporting evidence still comes from preclinical studies or bioinformatics rather than prospective clinical data. The only GC-specific registered disulfiram-based trial identified here remains exploratory, and no posted results currently establish clinical efficacy in GC[86]. Cuproptosis sensitivity may depend on mitochondrial metabolism, copper transporter expression, lipoylation, and the TME, which means that unselected patients may not benefit equally. Manipulating copper can harm normal tissues, as it is essential for mitochondrial respiration, antioxidant defense, angiogenesis, and neurological function. While cuproptosis may help overcome chemotherapy resistance, its ability to reverse resistance to targeted therapy or immunotherapy remains uncertain. Resistance could arise through altered copper uptake, metabolic adaptation, antioxidant buffering, autophagy, or ubiquitin-proteasome responses. To address these issues, future research should prioritize mechanistic validation, biomarker-driven patient selection, tumor-targeted delivery, rational combinations, and rigorous safety monitoring.

CONCLUSION

Cuproptosis connects copper imbalance with mitochondrial metabolism, proteotoxic stress, immune remodeling, angiogenesis, and treatment resistance in GC. Copper-modulating therapies and biomarkers, including FDX1, AOC1, ITGB1, and SERPINE1, may help stratify patients and guide future combination treatment. Current evidence remains mainly preclinical, so mechanistic validation, biomarker-guided trials, and careful safety monitoring are needed before these strategies can be used in routine care.