Disulfiram Facilitates Intracellular Cu Uptake and Induces Apoptosis in Human Melanoma Cells

Cu Nanowires Trigger Efficient Cuproptosis via Special Intracellular Distribution and Excessive Cu Ion Release

Cuproptosis, dependent on Cu overload, presents novel opportunities for cancer therapy. Cu-based nanomaterials have shown excellent advantages for the intracellular delivery of Cu. However, the biological process of Cu nanomaterials transporting Cu ions into cancer cells remains unclear. In this study, we tracked the Cu ion release process of copper nanowires (CuNWs) and copper nanoparticles (CuNPs) at the single-cell level. CuNWs with 5-μm length and CuNPs were found to be completely internalized by cancer cells. Interestingly, CuNWs escaped from the endolysosomal system, whereas CuNPs were mainly trapped in the lysosomes. This specific intracellular distribution of CuNWs led to cytoplasmic Cu ion overload, directly damaging mitochondria and inducing dihydrolipoamide S-acetyltransferase (DLAT) protein aggregation. Through these excessive Cu ions, CuNWs triggered more efficient cuproptosis than CuNPs to further increase cell death. Thus, CuNWs are more effective in delivering Cu ions than CuNPs, providing a novel perspective for designing cuproptosis-based functional nanomaterials for cancer therapy.

GSH exhaustion via inhibition of xCT-GSH-GPX4 pathway synergistically enhanced DSF/Cu-induced cuproptosis in myelodysplastic syndromes

The clinical application of the therapeutic approach in myelodysplastic syndromes (MDS) remains an insurmountable challenge for the high propensity for progressing to acute myeloid leukemia and predominantly affecting elderly individuals. Thus, the discovery of molecular mechanisms underlying the regulatory network of different programmed cell death holds great promise for the identification of therapeutic targets and provides insights into new therapeutic avenues. Herein, we found that disulfiram/copper (DSF/Cu) significantly repressed the cell viability, increased reactive oxygen species (ROS) accumulation, destroyed mitochondrial morphology, and altered oxygen consumption rate. Further studies verified that DSF/Cu induces cuproptosis, as evidenced by the depletion of glutathione (GSH), aggregation of lipoylated DLAT, and induced loss of Fe-S cluster-containing proteins, which could be rescued by tetrathiomolybdate and knockdown of ferredoxin 1 (FDX1). Additionally, GSH contributed to the tolerance of DSF/Cu-mediated cuproptosis, while pharmacological chelation of GSH triggered ROS accumulation and sensitized cell death. The xCT-GSH-GPX4 axis is the ideal downstream component of ferroptosis that exerts a powerful protective mechanism. Notably, classical xCT inhibitors were capable of leading to the catastrophic accumulation of ROS and exerting synergistic cell death, while xCT overexpression restored these phenomena. Simvastatin, an inhibitor of HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase, has beneficial effects in repurposing for inhibiting GPX4. Similarly, the combination treatment of DSF/Cu and simvastatin dramatically decreased the expression of GPX4 and Fe-S proteins, ultimately accelerating cell death. Moreover, we identified that the combination treatment of DSF/Cu and simvastatin also had a synergistic antitumor effect in the MDS mouse model, with the reduced GPX4, increased COX-2 and accumulated lipid peroxides. Overall, our study provided insight into developing a novel synergistic strategy to sensitize MDS therapy by targeting ferroptosis and cuproptosis.

Targeting cuproptosis for cancer therapy: mechanistic insights and clinical perspectives

Cuproptosis is a newly identified form of cell death induced by excessive copper (Cu) accumulation within cells. Mechanistically, cuproptosis results from Cu-induced aggregation of dihydrolipoamide S-acetyltransferase, correlated with the mitochondrial tricarboxylic acid cycle and the loss of iron-sulfur cluster proteins, ultimately resulting in proteotoxic stress and triggering cell death. Recently, cuproptosis has garnered significant interest in tumor research due to its potential as a crucial therapeutic strategy against cancer. In this review, we summarized the cellular and molecular mechanisms of cuproptosis and its relationship with other types of cell death. Additionally, we reviewed the current drugs or strategies available to induce cuproptosis in tumor cells, including Cu ionophores, small compounds, and nanomedicine. Furthermore, we targeted cell metabolism and specific regulatory genes in cancer therapy to enhance tumor sensitivity to cuproptosis. Finally, we discussed the feasibility of targeting cuproptosis to overcome tumor chemotherapy and immunotherapy resistance and suggested future research directions. This study suggested that targeting cuproptosis could open new avenues for developing tumor therapy.

Copper Homeostasis Based on Cuproptosis-Related Signature Optimizes Molecular Subtyping and Treatment of Glioma

Copper is essential in living organisms and crucial to various physiological processes. Normal physiological conditions are in a state of copper homeostasis to ensure normal biochemical and metabolic processes. Dysregulation of copper homeostasis has been associated with multiple diseases, especially cancer. Cuproptosis is a copper-dependent cell death mediated by excess copper or homeostasis dysregulation. Elesclomol is a common inducer of cuproptosis, carrying copper into the cell and producing excess copper. Cuproptosis modulates tumor proliferation-related signaling pathways and is closely associated with remodeling the tumor microenvironment. In gliomas, the role of cuproptosis and copper homeostasis needs to be better characterized. This study systematically analyzed cuproptosis-related genes (CRGs) and constructed a cuproptosis signature for gliomas. The signature closely links the subtypes and clinical features of glioma patients. The results showed a greater tendency toward dysregulation of copper homeostasis as the malignant grade of glioma patients increased. In addition, CRGs-signature effectively predicted the sensitivity of glioma cells to elesclomol and verified that elesclomol inhibited glioma mainly through inducing cellular cuproptosis. In summary, we found different copper homeostatic features in gliomas and verified the anticancer mechanism of elesclomol, which provides a theoretical basis for developing novel therapeutic strategies for gliomas.

Regenerating Chemotherapeutics through Copper-Based Nanomedicine: Disrupting Protein Homeostasis for Enhanced Tumor Therapy

The bis-(diethyldithiocarbamate)-copper (CuET), the disulfiram (DSF)-Cu complex, has exhibited noteworthy anti-tumor property. However, its efficacy is compromised due to the inadequate oxidative conditions and the limitation of bioavailable copper. Because CuET can inactivate valosin-containing protein (VCP), a bioinformatic pan-cancer analysis of VCP is first conducted in this study to identify CuET as a promising anticancer drug for diverse cancer types. Then, based on the drug action mechanism, a nanocomposite of CuET and copper oxide (CuO) is designed and fabricated utilizing bovine serum albumin (BSA) as the template (denoted as CuET-CuO@BSA, CCB). CCB manifests peroxidase (POD)-mimicking activity to oxidize the tumor endogenous H2O2 to generate reactive oxygen species (ROS), enhancing the chemotherapy effect of CuET. Furthermore, the cupric ions released after enzymatic reaction can regenerate CuET, which markedly perturbs intracellular protein homeostasis and induces apoptosis of tumor cells. Meanwhile, CCB triggers cuproptosis by inducing the aggregation of lipoylated proteins. The multifaceted action of CCB effectively inhibits tumor progression. Therefore, this study presents an innovative CuET therapeutic strategy that creates an oxidative microenvironment in situ and simultaneously self-supply copper source for CuET regeneration through the combination of CuO nanozyme with CuET, which holds promise for application of CuET for effective tumor therapy.

Cuproptosis and physical training: A review

Copper is an essential element in the human body, involved in many physiological and metabolic functions, including coagulation, oxidative metabolism, and hormone production. The maintenance of copper homeostasis within cells is a complex procedure that is intrinsically controlled by a multitude of intricate mechanisms. Disorders of copper homeostasis encompass a wide range of pathological conditions, including degenerative neurological diseases, metabolic disorders, cardio-cerebrovascular diseases, and tumors. Cuproptosis, a recently identified non-apoptotic mode of cell death mode, is characterized by copper dependence and the regulation of mitochondrial respiration. Cuproptosis represents a novel form of cell death distinct from the previously described modes, including apoptosis, necrosis, pyroptosis, and ferroptosis. Excess copper has been shown to induce cuproptosis by stimulating protein toxic stress responses via copper-dependent abnormal oligomerization of lipoylation proteins within the tricarboxylic acid cycle and the subsequent reduction of iron-sulfur cluster protein levels. Ferredoxin1 facilitates the lipoacylation of dihydrolipoyl transacetylase, which in turn degrades iron-sulfur cluster proteins by reducing Cu2+ to Cu+, thereby inducing cell death. Furthermore, copper homeostasis is regulated by the copper transporter, and disturbances in this homeostasis result in cuproptosis. Current evidence suggests that cuproptosis plays an important role in the onset and development of several cardiovascular diseases. Copper-chelating agents, including ammonium tetrathiomolybdate (VI) and DL-penicillamine, have been shown to facilitate the alleviation of cardiovascular disease by inhibiting cuproptosis. It is hypothesized that oxidative phosphorylation inhibitors such as physical training may inhibit cuproptosis by inhibiting the protein stress response. In conclusion, the implementation of physical training may be a viable strategy to reducte the incidence of cuproptosis.

Cuproptosis-related gene DLAT is a biomarker of the prognosis and immune microenvironment of gastric cancer and affects the invasion and migration of cells

OBJECTIVE

Cuproptosis is a novel cell death dependent on mitochondrial respiration and regulated by copper. This study aimed to investigate the cuproptosis-related gene DLAT potential value in gastric cancer (GC).

METHODS

Bioinformatics was used to analyze DLAT expression. DLAT expression in GC cell lines was detected using qRT-PCR. Cell proliferation ability was assessed using CCK8 and cell cycle assay. Cell migration and invasion were assessed using wound healing and transwell assay. A prognostic assessment was performed through survival and Cox regression analysis. DLAT protein expression was analyzed through HPA immunohistochemistry. Biological functions and processes were analyzed through GO and KEGG enrichment analysis and PPI. Correlation with immune cell infiltration and immune checkpoint genes was analyzed for DLAT.

RESULTS

DLAT expression was upregulated in GC tissues and cells and correlated with shorter survival for patients. Age, gender, histological typing, lymph node metastasis, and distant metastasis were identified as independent prognostic factors affecting OS in GC. DLAT protein was upregulated in GC. The biological functions and pathways enriched in DLAT were mainly linked to mitochondrial respiration and the TCA cycle. The expression of DLAT was found to be positively correlated with the infiltration of Th and Th2 immune cells and only positively correlated with the expression of the BTN2A1 immune checkpoint gene.

CONCLUSION

DLAT has the potential to serve as a prognostic assessment factor in GC. The expression of DLAT was correlated with immune infiltration and tumor immune escape, providing a new target for immunotherapy of GC.

Quality-by-design-based microemulsion of disulfiram for repurposing in melanoma and breast cancer therapy

Aim: The current study aims to develop and optimize microemulsions (ME) through Quality-by-Design (QbD) approach to improve the aqueous solubility and dissolution of poorly water-soluble drug disulfiram (DSF) for repurposing in melanoma and breast cancer therapy.Materials & methods: The ME was formulated using Cinnamon oil & Tween® 80, statistically optimized using a D-optimal mixture design-based QbD approach to develop the best ME with low vesicular size (Zavg) and polydispersity index (PDI).Results: The DSF-loaded optimized stable ME showed enhanced dissolution, in-vitro cytotoxicity and improved cellular uptake in B16F10 and MCF-7 cell lines compared with their unformulated free DSF.Conclusion: Our investigations suggested the potential of the statistically designed DSF-loaded optimized ME for repurposing melanoma and breast cancer therapy.

Cuproptosis in cancer: biological implications and therapeutic opportunities

Cuproptosis, a newly identified copper (Cu)-dependent form of cell death, stands out due to its distinct mechanism that sets it apart from other known cell death pathways. The molecular underpinnings of cuproptosis involve the binding of Cu to lipoylated enzymes in the tricarboxylic acid cycle. This interaction triggers enzyme aggregation and proteotoxic stress, culminating in cell death. The specific mechanism of cuproptosis has yet to be fully elucidated. This newly recognized form of cell death has sparked numerous investigations into its role in tumorigenesis and cancer therapy. In this review, we summarized the current knowledge on Cu metabolism and its link to cancer. Furthermore, we delineated the molecular mechanisms of cuproptosis and summarized the roles of cuproptosis-related genes in cancer. Finally, we offered a comprehensive discussion of the most recent advancements in Cu ionophores and nanoparticle delivery systems that utilize cuproptosis as a cutting-edge strategy for cancer treatment.

Clinical features and molecular landscape of cuproptosis signature-related molecular subtype in gastric cancer

Recent studies have highlighted the biological significance of cuproptosis in disease occurrence and development. However, it remains unclear whether cuproptosis signaling also has potential impacts on tumor initiation and prognosis of gastric cancer (GC). In this study, 16 cuproptosis-related genes (CRGs) transcriptional profiles were harnessed to perform the regularized latent variable model-based clustering in GC. A cuproptosis signature risk scoring (CSRS) scheme, based on a weighted sum of principle components of the CRGs, was used to evaluate the prognosis and risk of individual tumors of GC. Four distinct cuproptosis signature-based clusters, characterized by differential expression patterns of CRGs, were identified among 1136 GC samples across three independent databases. The four clusters were also associated with different clinical outcomes and tumor immune contexture. Based on the CSRS, GC patients can be divided into CSRS-High and CSRS-Low subtypes. We found that DBT, MTF1, and ATP7A were significantly elevated in the CSRS-High subtype, while SLC31A1, GCSH, LIAS, DLAT, FDX1, DLD, and PDHA1 were increased in the CSRS-Low subtype. Patients with CSRS-Low score were characterized by prolonged survival time. Further analysis indicated that CSRS-Low score also correlated with greater tumor mutation burden (TMB) and higher mutation rates of significantly mutated genes (SMG) in GC. In addition, the CSRS-High subtype harbored more significantly amplified focal regions related to tumorigenesis (3q27.1, 12p12.1, 11q13.3, etc.) than the CSRS-Low tumors. Drug sensitivity analyses revealed the potential compounds for the treatment of gastric cancer with CSRS-High score, which were experimentally validated using GC cells. This study highlights that cuproptosis signature-based subtyping is significantly associated with different clinical features and molecular landscape of GC. Quantitative evaluation of the CSRS of individual tumors will strengthen our understanding of the occurrence and development of cuproptosis and the treatment progress of GC.

Cyclodextrin encapsulation enabling the anticancer repositioning of disulfiram: Preparation, analytical and in vitro biological characterization of the inclusion complexes

Drug repositioning is a high-priority and feasible strategy in the field of oncology research, where the unmet medical needs are continuously unbalanced. Disulfiram is a potential non-chemotherapeutic, adjuvant anticancer agent. However, the clinical translation is limited by the drug's poor bioavailability. Therefore, the molecular encapsulation of disulfiram with cyclodextrins is evaluated to enhance the solubility and stability of the drug. The present work describes for the first time the complexation of disulfiram with randomly methylated-β-cyclodextrin. A parallel analytical andin vitrobiological comparison of disulfiram inclusion complexes with hydroxypropyl-β-cyclodextrin, randomly methylated-β-cyclodextrin and sulfobutylether-β-cyclodextrin is conducted. A significant drug solubility enhancement by about 1000-folds and fast dissolution in 1 min is demonstrated. Thein vitrodissolution-permeation studies and proliferation assays demonstrate the solubility-dependent efficacy of the drug. Throughout the different cancer cell lines' characteristics and disulfiram unspecific antitumoral activity, the inhibitory efficacy of the cyclodextrin encapsulated drug on melanoma (IC50 about 100 nM) and on glioblastoma (IC50 about 7000 nM) cell lines differ by a magnitude. This pre-formulation screening experiment serves as a proof of concept of using cyclodextrin encapsulation as a platform tool for further drug delivery development in repositioning areas.

Cuproptosis: unveiling a new frontier in cancer biology and therapeutics

Copper plays vital roles in numerous cellular processes and its imbalance can lead to oxidative stress and dysfunction. Recent research has unveiled a unique form of copper-induced cell death, termed cuproptosis, which differs from known cell death mechanisms. This process involves the interaction of copper with lipoylated tricarboxylic acid cycle enzymes, causing protein aggregation and cell death. Recently, a growing number of studies have explored the link between cuproptosis and cancer development. This review comprehensively examines the systemic and cellular metabolism of copper, including tumor-related signaling pathways influenced by copper. It delves into the discovery and mechanisms of cuproptosis and its connection to various cancers. Additionally, the review suggests potential cancer treatments using copper ionophores that induce cuproptosis, in combination with small molecule drugs, for precision therapy in specific cancer types.

Turning anecdotal irradiation-induced anticancer immune responses into reproducible in situ cancer vaccines via disulfiram/copper-mediated enhanced immunogenic cell death of breast cancer cells

Irradiation (IR) induces immunogenic cell death (ICD) in tumors, but it rarely leads to the abscopal effect (AE); even combining IR with immune checkpoint inhibitors has shown only anecdotal success in inducing AEs. In this study, we aimed to enhance the IR-induced immune response and generate reproducible AEs using the anti-alcoholism drug, disulfiram (DSF), complexed with copper (DSF/Cu) to induce tumor ICD. We measured ICD in vitro and in vivo. In mouse tumor models, DSF/Cu was injected intratumorally followed by localized tumor IR, creating an in situ cancer vaccine. We determined the anticancer response by primary tumor rejection and assessed systemic immune responses by tumor rechallenge and the occurrence of AEs relative to spontaneous lung metastasis. In addition, we analyzed immune cell subsets and quantified proinflammatory and immunosuppressive chemokines/cytokines in the tumor microenvironment (TME) and blood of the vaccinated mice. Immune cell depletion was investigated for its effects on the vaccine-induced anticancer response. The results showed that DSF/Cu and IR induced more potent ICD under hypoxia than normoxia in vitro. Low-dose intratumoral (i.t.) injection of DSF/Cu and IR(12Gy) demonstrated strong anti-primary and -rechallenged tumor effects and robust AEs in mouse models. These vaccinations also increased CD8+ and CD4+ cell numbers while decreasing Tregs and myeloid-derived suppressor cells in the 4T1 model, and increased CD8+, dendritic cells (DC), and decreased Treg cell numbers in the MCa-M3C model. Depleting both CD8+ and CD4+ cells abolished the vaccine's anticancer response. Moreover, vaccinated tumor-bearing mice exhibited increased TNFα levels and reduced levels of immunosuppressive chemokines/cytokines. In conclusion, our novel approach generated an anticancer immune response that results in a lack of or low tumor incidence post-rechallenge and robust AEs, i.e., absence of or decreased spontaneous lung metastasis in tumor-bearing mice. This approach is readily translatable to clinical settings and may increase IR-induced AEs in cancer patients.

Tumor-Microenvironment-Responsive Cerium-Enriched Copper Nanozyme with O2 Supply and Oxidative Stress Amplification for In Situ Disulfiram Chemotherapy and Chemodynamic Therapy Intensification

Traditional chemotherapy has faced tough challenges of systemic toxicity, hypoxia resistance, and inadequacy of monotherapy. Developing the tumor-specific O2-supply-enhanced chemotherapy without toxic drugs while combing other precise treatments can substantially improve therapeutic efficacy. Herein, a CeO2-enriched CuO nanozyme with O2 supply and oxidative stress amplification for tumor-specific disulfiram (DSF) chemotherapy and intensified chemodynamic therapy by synergistic in situ "nontoxicity-toxicity" activation is developed. Notably, CeO2 can not only act as a morphological "regulator," but also serve as a cascaded enzyme-mimetic catalyst via tumor-microenvironment-responsive cascaded-logical programmable valence conversion. Once internalized inside tumor cells, the nanozyme can be degraded by lysosomal acidity to release nontoxic DSF and Cu2+, which can trigger in situ "Cu2+-DSF" chelation, generating a highly toxic Cu(DTC)2 for in situ chemotherapy. Moreover, the enriched CeO2 with catalase-mimetic activity can decompose the endogenous H2O2 into O2, which can relieve the hypoxia to enhance the chemotherapeutic efficacy. Furthermore, the simultaneously generated Ce3+ can exert peroxidase-mimetic activity to catalyze H2O2 into hydroxyl radicals (•OH) for chemodynamic therapy. This Fenton-like chemistry is accompanied by the regeneration of Ce4+, which can deplete the intracellular overproduced GSH to amplify the oxidative stress. Therefore, this nanozyme can provide an alternative to precise cancer treatment.

Cuproptosis: Unraveling the Mechanisms of Copper-Induced Cell Death and Its Implication in Cancer Therapy

Copper, an essential element for various biological processes, demands precise regulation to avert detrimental health effects and potential cell toxicity. This paper explores the mechanisms of copper-induced cell death, known as cuproptosis, and its potential health and disease implications, including cancer therapy. Copper ionophores, such as elesclomol and disulfiram, increase intracellular copper levels. This elevation triggers oxidative stress and subsequent cell death, offering potential implications in cancer therapy. Additionally, copper ionophores disrupt mitochondrial respiration and protein lipoylation, further contributing to copper toxicity and cell death. Potential targets and biomarkers are identified, as copper can be targeted to those proteins to trigger cuproptosis. The role of copper in different cancers is discussed to understand targeted cancer therapies using copper nanomaterials, copper ionophores, and copper chelators. Furthermore, the role of copper is explored through diseases such as Wilson and Menkes disease to understand the physiological mechanisms of copper. Exploring cuproptosis presents an opportunity to improve treatments for copper-related disorders and various cancers, with the potential to bring significant advancements to modern medicine.

Augmenting MEK inhibitor efficacy in BRAF wild-type melanoma: synergistic effects of disulfiram combination therapy

BACKGROUND

MEK inhibitors (MEKi) were shown to be clinically insufficiently effective in patients suffering from BRAF wild-type (BRAF WT) melanoma, even if the MAPK pathway was constitutively activated due to mutations in NRAS or NF-1. Thus, novel combinations are needed to increase the efficacy and duration of response to MEKi in BRAF WT melanoma. Disulfiram and its metabolite diethyldithiocarbamate are known to have antitumor effects related to cellular stress, and induction of endoplasmic reticulum (ER) stress was found to synergize with MEK inhibitors in NRAS-mutated melanoma cells. Therefore, we investigated the combination of both therapeutics to test their effects on BRAF-WT melanoma cells and compared them with monotherapy using the MEKi trametinib.

METHODS

The effects of combined therapy with disulfiram or its metabolite diethyldithiocarbamate and the MEKi trametinib were evaluated in a series of BRAF-WT melanoma cell lines by measuring cell viability and apoptosis induction. Cytotoxicity was additionally assessed in 3D spheroids, ex vivo melanoma slice cultures, and in vivo xenograft mouse models. The response of melanoma cells to treatment was studied at the RNA and protein levels to decipher the mode of action. Intracellular and intratumoral copper measurements were performed to investigate the role of copper ions in the antitumor cytotoxicity of disulfiram and its combination with the MEKi.

RESULTS

Diethyldithiocarbamate enhanced trametinib-induced cytotoxicity and apoptosis induction in 2D and 3D melanoma culture models. Mechanistically, copper-dependent induction of oxidative stress and ER stress led to Janus kinase (JNK)-mediated apoptosis in melanoma cells. This mechanism was also detectable in patient-derived xenograft melanoma models and resulted in a significantly improved therapeutic effect compared to monotherapy with the MEKi trametinib.

CONCLUSIONS

Disulfiram and its metabolite represent an attractive pharmaceutical approach to induce ER stress in melanoma cells that potentiates the antitumor effect of MEK inhibition and may be an interesting candidate for combination therapy of BRAF WT melanoma.

The construction of hierarchical assemblies with in situ generation of chemotherapy drugs to enhance the efficacy of chemodynamic therapy for multi-modal anti-tumor treatments

The effectiveness of chemodynamic therapy (CDT) in cancer treatment is limited by insufficient endogenous H2O2 levels in tumor tissue and an increasing ratio of high valence metal ions. To overcome these challenges, a novel nanotherapeutic approach, named GOx-CuCaP-DSF, has been proposed. This approach involves the design of nanotherapeutics that aim to self-supply H2O2 within cancer cells and provide a supplement of low valence metal ions to enhance the performance of CDT. GOx-CuCaP-DSF nanotherapeutics are engineered by incorporating glucose oxidase (GOx) into Ca2+-doped calcium phosphate (CaP) nanoparticles and loading disulfiram (DSF) through surface adsorption. Under the tumor microenvironment, GOx catalyzes the conversion of tumor-overexpressed glucose (Glu) to liberate H2O2. The degradation of CaP further lowers the pH, facilitating the release of Cu2+ ions and DSF. The rapid reaction between Cu2+ and DSF leads to the generation of Cu+, increasing the Cu+/Cu2+ ratio and promoting the Cu+-based Fenton reaction, which enhances the efficiency of CDT. Simultaneously, DSF undergoes conversion to diethyldithiocarbamate acid (ET), forming a copper(II) complex (Cu(II)ET) by strong chelation with Cu ions. This Cu(II)ET complex, a potent chemotherapeutic drug, exhibits a synergistic therapeutic effect in combination with CDT. Moreover, the elevated Cu+ species resulting from DSF reaction promotes the aggregation of toxic mitochondrial proteins, leading to cell cuproptosis. Overall, the strategy of integrating the chemodynamic therapy efficiency of the Fenton reaction with the activation of efficacious cuproptosis using a chemotherapeutic drug presents a promising avenue for enhancing the effectiveness of multi-modal anti-tumor treatments.

Small-molecule redox modulators with anticancer activity: A comprehensive mechanistic update

The pursuit of effective anticancer therapies has led to a burgeoning interest in the realm of redox modulation. This review provides a comprehensive exploration of the intricate mechanisms by which diverse anticancer molecules leverage redox pathways for therapeutic intervention. Redox modulation, encompassing the fine balance of oxidation-reduction processes within cells, has emerged as a pivotal player in cancer treatment. This review delves into the multifaceted mechanisms of action employed by various anticancer compounds, including small molecules and natural products, to disrupt cancer cell proliferation and survival. Beginning with an examination of the role of redox signaling in cancer development and resistance, the review highlights how aberrant redox dynamics can fuel tumorigenesis. It then meticulously dissects the strategies employed by anticancer agents to induce oxidative stress, perturb redox equilibrium, and trigger apoptosis within cancer cells. Furthermore, the review explores the challenges and potential side effects associated with redox-based treatments, along with the development of novel redox-targeted agents. In summary, this review offers a profound understanding of the dynamic interplay between redox modulation and anticancer molecules, presenting promising avenues to revolutionize cancer therapy and enhance patient outcomes.

Cuproptosis: emerging biomarkers and potential therapeutics in cancers

The sustenance of human life activities depends on copper, which also serves as a crucial factor for vital enzymes. Under typical circumstances, active homeostatic mechanisms keep the intracellular copper ion concentration low. Excess copper ions cause excessive cellular respiration, which causes cytotoxicity and cell death as levels steadily rise above a threshold. It is a novel cell death that depends on mitochondrial respiration, copper ions, and regulation. Cuproptosis is now understood to play a role in several pathogenic processes, including inflammation, oxidative stress, and apoptosis. Copper death is a type of regulatory cell death(RCD).Numerous diseases are correlated with the development of copper homeostasis imbalances. One of the most popular areas of study in the field of cancer is cuproptosis. It has been discovered that cancer angiogenesis, proliferation, growth, and metastasis are all correlated with accumulation of copper ions. Copper ion concentrations can serve as a crucial marker for cancer development. In order to serve as a reference for clinical research on the product, diagnosis, and treatment of cancer, this paper covers the function of copper ion homeostasis imbalance in malignant cancers and related molecular pathways.

Novel insights into anticancer mechanisms of elesclomol: More than a prooxidant drug

As an essential micronutrient for humans, the metabolism of copper is fine-tuned by evolutionarily conserved homeostatic mechanisms. Copper toxicity occurs when its concentration exceeds a certain threshold, which has been exploited in the development of copper ionophores, such as elesclomol, for anticancer treatment. Elesclomol has garnered recognition as a potent anticancer drug and has been evaluated in numerous clinical trials. However, the mechanisms underlying elesclomol-induced cell death remain obscure. The discovery of cuproptosis, a novel form of cell death triggered by the targeted accumulation of copper in mitochondria, redefines the significance of elesclomol in cancer therapy. Here, we provide an overview of copper homeostasis and its associated pathological disorders, especially copper metabolism in carcinogenesis. We summarize our current knowledge of the tumor suppressive mechanisms of elesclomol, with emphasis on cuproptosis. Finally, we discuss the strategies that may contribute to better application of elesclomol in cancer therapy.

A disulfiram/copper gluconate co-loaded bi-layered long-term drug delivery system for intraperitoneal treatment of peritoneal carcinomatosis

To develop a long-term drug delivery system for the treatment of primary and metastatic peritoneal carcinoma (PC) by intraperitoneal (IP) injection, a disulfiram (DSF)/copper gluconate (Cu-Glu)-co-loaded bi-layered poly (lactic acid-coglycolic acid) (PLGA) microspheres (Ms) - thermosensitive hydrogel system (DSF-Ms-Cu-Glu-Gel) was established. Rate and mechanisms of drug release from DSF-Ms-Cu-Glu-Gel were explored. The anti-tumor effects of DSF-Ms-Cu-Glu-Gel by IP injection were evaluated using H22 xenograft tumor model mice. The accumulative release of DSF from Ms on the 10th day was 83.79% without burst release. When Ms were dispersed into B-Gel, burst release at 24 h decreased to 14.63%. The results showed that bis (diethyldithiocarbamate)-copper (Cu(DDC)2) was formed in DSF-Ms-Cu-Glu-Gel and slowly released from B-Gel. In a pharmacodynamic study, the mount of tumor nodes and ascitic fluid decreased in the DSF-Ms-Cu-Glu-Gel group. This was because: (1) DSF-Ms-Cu-Glu-Gel system co-loaded DSF and Cu-Glu, and physically isolated DSF and Cu-Glu before injection to protect DSF; (2) space and water were provided for the formation of Cu(DDC)2; (3) could provide an effective drug concentration in the abdominal cavity for a long time; (4) both DSF and Cu(DDC)2 were effective anti-tumor drugs, and the formation of Cu(DDC)2 occurred in the abdominal cavity, which further enhanced the anti-tumor activity. Thus, the DSF-Ms-Cu-Glu-Gel system can be potentially used for the IP treatment of PC in the future.

Cuproptosis: Harnessing Transition Metal for Cancer Therapy

Transition metal elements, such as copper, play diverse and pivotal roles in oncology. They act as constituents of metalloenzymes involved in cellular metabolism, function as signaling molecules to regulate the proliferation and metastasis of tumors, and are integral components of metal-based anticancer drugs. Notably, recent research reveals that excessive copper can also modulate the occurrence of programmed cell death (PCD), known as cuprotosis, in cancer cells. This modulation occurs through the disruption of tumor cell metabolism and the induction of proteotoxic stress. This discovery uncovers a mode of interaction between transition metals and proteins, emphasizing the intricate link between copper homeostasis and tumor metabolism. Moreover, they provide innovative therapeutic strategies for the precise diagnosis and treatment of malignant tumors. At the crossroads of chemistry and oncology, we undertake a comprehensive review of copper homeostasis in tumors, elucidating the molecular mechanisms underpinning cuproptosis. Additionally, we summarize current nanotherapeutic approaches that target cuproptosis and provide an overview of the available laboratory and clinical methods for monitoring this process. In the context of emerging concepts, challenges, and opportunities, we emphasize the significant potential of nanotechnology in the advancement of this field.

Enhanced pH-Responsive Chemo/Chemodynamic Synergistic Cancer Therapy Based on In Situ Cu2+ Di-Chelation

Considering the chemodynamic therapy and chemotherapy independent of external stimulus witnessing great advantage in the clinical translation, developing a smart nanoplatform that can realize enhanced chemo/chemodynamic synergistic therapy in the tumor microenvironment (TME) is of great significance. Herein, we highlight the enhanced pH-responsive chemo/chemodynamic synergistic cancer therapy based on in situ Cu2+ di-chelation. The alcohol-withdrawal drug disulfiram (DSF) and chemotherapeutic drug mitoxantrone (MTO) were embedded into PEGylated mesoporous CuO (denoted as PEG-CuO@DSF@MTO NPs). The acidic TME triggered the collapse of CuO and the concurrent release of Cu2+, DSF, and MTO. Then, the in situ complexation between Cu2+ and DSF, as well as the coordination between Cu2+ and MTO not only prominently enhanced the chemotherapeutic performance but also triggered the chemodynamic therapy. In vivo mouse model experiments demonstrated that the synergistic therapy can remarkably eliminate tumors. This study provides an interesting strategy to design intelligent nanosystems, which could proceed to clinical translations.

Turning anecdotal irradiation-induced anti-cancer immune responses into reproducible in situ cancer vaccines via disulfiram/copper-mediated enhanced immunogenic cell death of breast cancer cells

Irradiation (IR) induces immunogenic cell death (ICD) in tumors, but it rarely leads to the abscopal effect (AE). However, combining IR with immune checkpoint inhibitors has shown anecdotal success in inducing AEs. In this study, we aimed to enhance the IR-induced immune response and generate reproducible AEs using the anti-alcoholism drug disulfiram (DSF) and copper complex (DSF/Cu) via induction of tumor ICD. We measured ICD in vitro and in vivo. In mouse tumor models, DSF/Cu was injected intratumorally followed by localized tumor IR, creating an in situ cancer vaccine. We determined the anti-cancer response by primary tumor rejection and assessed systemic immune responses by tumor rechallenge and the occurrence of AEs, i.e., spontaneous lung metastasis. Additionally, we analyzed immune cell subsets and quantified proinflammatory and immunosuppressive chemokines/cytokines in the tumor microenvironment (TME) and blood of the vaccinated mice. Immune cell depletion was investigated for its effects on the vaccine-induced anti-cancer response. The results showed that DSF/Cu and IR induced more potent ICD under hypoxia than normoxia in vitro. Low-dose intratumoral injection of DSF/Cu and IR demonstrated strong anti-primary and -rechallenged tumor effects and robust AEs in mouse models. These vaccinations also increased CD8 + and CD4 + cell numbers while decreasing Tregs and myeloid-derived suppressor cells in the 4T1 model, and increased CD8+, DC, and decreased Treg cell numbers in the MCa-M3C model. Depleting both CD8 + and CD4 + cells abolished the vaccine's anticancer response. Moreover, vaccinated tumor-bearing mice exhibited increased TNFα levels and reduced levels of immunosuppressive chemokines/cytokines. In conclusion, our novel approach generated an anti-cancer immune response, resulting in a lack of or low tumor incidence post-rechallenge and robust AEs, i.e., the absence of or decreased spontaneous lung metastasis in tumor-bearing mice. This approach is readily translatable to clinical settings and may increase IR-induced AEs in cancer patients.

Copper-instigated modulatory cell mortality mechanisms and progress in oncological treatment investigations

Copper, a transition metal, serves as an essential co-factor in numerous enzymatic active sites and constitutes a vital trace element in the human body, participating in crucial life-sustaining activities such as energy metabolism, antioxidation, coagulation, neurotransmitter synthesis, iron metabolism, and tetramer deposition. Maintaining the equilibrium of copper ions within biological systems is of paramount importance in the prevention of atherosclerosis and associated cardiovascular diseases. Copper induces cellular demise through diverse mechanisms, encompassing reactive oxygen species responses, apoptosis, necrosis, pyroptosis, and mitochondrial dysfunction. Recent research has identified and dubbed a novel regulatory cell death modality-"cuprotosis"-wherein copper ions bind to acylated proteins in the tricarboxylic acid cycle of mitochondrial respiration, resulting in protein aggregation, subsequent downregulation of iron-sulfur cluster protein expression, induction of proteotoxic stress, and eventual cell death. Scholars have synthesized copper complexes by combining copper ions with various ligands, exploring their significance and applications in cancer therapy. This review comprehensively examines the multiple pathways of copper metabolism, copper-induced regulatory cell death, and the current status of copper complexes in cancer treatment.

A tumor microenvironment-responsive core-shell tecto dendrimer nanoplatform for magnetic resonance imaging-guided and cuproptosis-promoted chemo-chemodynamic therapy

Theranostic nanoplatforms for combination tumor therapy have gained lots of attention recently due to the optimized therapeutic efficiency and simultaneous diagnosis performance. Herein, a novel tumor microenvironment (TME)-responsive core-shell tecto dendrimer (CSTD) was assembled by phenylboronic acid- and mannose-modified poly(amidoamine) dendrimers via the phenylboronic ester bonds that are responsive to low pH and reactive oxygen species (ROS), and efficiently loaded with copper ions and chemotherapeutic drug disulfiram (DSF) for tumor-targeted magnetic resonance (MR) imaging and cuproptosis-promoted chemo-chemodynamic therapy. The formed CSTD-Cu(II)@DSF could be specifically taken up by MCF-7 breast cancer cells, accumulated to the tumor model after circulation, and released drugs in response to the weakly acidic TME with overexpressed ROS. The enriched intracellular Cu(II) ions could induce the oligomerization of lipoylated proteins and proteotoxic stress for cuproptosis, and lipid peroxidation for chemodynamic therapy as well. Moreover, the CSTD-Cu(II)@DSF could cause the dysfunction of mitochondria and arrest the cell cycle at the G2/M phase, leading to enhanced DSF-mediated cell apoptosis. As a result, CSTD-Cu(II)@DSF could effectively inhibit the growth of MCF-7 tumors by a combination therapy strategy integrating chemotherapy with cuproptosis and chemodynamic therapy. Lastly, the CSTD-Cu(II)@DSF also displays Cu(II)-associated r1 relaxivity, allowing for T1-weighted real-time MR imaging of tumors in vivo. The developed tumor-targeted and TME-responsive CSTD-based nanomedicine formulation may be developed for accurate diagnosis and synergistic treatment of other cancer types. STATEMENT OF SIGNIFICANCE: Constructing an effective nanoplatform for the combination of therapeutic effects and real-time tumor imaging remains a challenge. In this study, we reported for the first time an all-in-one tumor-targeted and tumor microenvironment (TME) responsive nanoplatform based on core-shell tecto dendrimer (CSTD) for the cuproptosis-promoted chemo-chemodynamic therapy and enhanced MR imaging. The efficient loading, selective tumor-targeting, and TME-responsive release of Cu(II) and disulfiram could enhance the intracellular accumulation of drugs, induce cuproptosis of cancer cells, and amplify the synergistic chemo-chemodynamic therapeutic effect, resulting in enhanced MR imaging and accelerated tumor eradication. This study sheds new light on the development of theranostic nanoplatforms for early accurate diagnosis and effective treatment of cancers.

Copper in cancer: from limiting nutrient to therapeutic target

As an essential nutrient, copper's redox properties are both beneficial and toxic to cells. Therefore, leveraging the characteristics of copper-dependent diseases or using copper toxicity to treat copper-sensitive diseases may offer new strategies for specific disease treatments. In particular, copper concentration is typically higher in cancer cells, making copper a critical limiting nutrient for cancer cell growth and proliferation. Hence, intervening in copper metabolism specific to cancer cells may become a potential tumor treatment strategy, directly impacting tumor growth and metastasis. In this review, we discuss the metabolism of copper in the body and summarize research progress on the role of copper in promoting tumor cell growth or inducing programmed cell death in tumor cells. Additionally, we elucidate the role of copper-related drugs in cancer treatment, intending to provide new perspectives for cancer treatment.

High-capacity glycol chitosan-based nanoemulsion for efficient delivery of disulfiram

Disulfiram (DS) is an anti-alcoholism drug capable of acting against important and hard-to-treat cancers. The drug's relative instability and variable absorption/distribution have led to its variable pharmacokinetics and suboptimal exposure. Hence, it was hypothesised that a nano-enabled form of DS might be able to overcome such limitations. Encapsulation of the labile DS was achieved with quaternary ammonium palmitoyl glycol chitosan (GCPQ) to form a high-capacity, soybean oil-based DS-GCPQ nanoemulsion. DS-GCPQ showed capability of oil-loading up to 50% v/v for a stable entrapment of high drug content. With increasing oil content (10 to 50% v/v), the mean particle size and polydispersity index were also increased (166 to 351 nm and 0.14 to 0.22, respectively) for a given amount of GCPQ. Formulations showed a highly positive particle surface charge (50.9 ± 1.3 mV), contributing to the colloidal stability of the individual particles. DS-GCPQ showed marked cytotoxicity against pancreatic cancer cell lines with enhanced activity in the presence of copper. An intravenous pharmacokinetic study of DS-GCPQ in vivo showed improved plasma drug stability with a DS half-life of 17 min. Prolonged survival was seen in tumour-bearing animals treated with DS-GCPQ supplemented with copper. In conclusion, DS-GCPQ nanoemulsion has the potential to be developed further for cancer therapeutic purposes.

Oxidative Stress in Melanoma: Beneficial Antioxidant and Pro-Oxidant Therapeutic Strategies

Cutaneous melanoma ranks as the fifth most common cancer in the United States and represents one of the deadliest forms of skin cancer. While recent advances in systemic targeted therapies and immunotherapies have positively impacted melanoma survival, the survival rate of stage IV melanoma remains at a meager 32%. Unfortunately, tumor resistance can impede the effectiveness of these treatments. Oxidative stress is a pivotal player in all stages of melanoma progression, with a somewhat paradoxical function that promotes tumor initiation but hinders vertical growth and metastasis in later disease. As melanoma progresses, it employs adaptive mechanisms to lessen oxidative stress in the tumor environment. Redox metabolic rewiring has been implicated in acquired resistance to BRAF/MEK inhibitors. A promising approach to enhance the response to therapy involves boosting intracellular ROS production using active biomolecules or targeting enzymes that regulate oxidative stress. The complex interplay between oxidative stress, redox homeostasis, and melanomagenesis can also be leveraged in a preventive context. The purpose of this review is to provide an overview of oxidative stress in melanoma, and how the antioxidant system may be manipulated in a therapeutic context for improved efficacy and survival.

Advancing Cancer Therapy with Copper/Disulfiram Nanomedicines and Drug Delivery Systems

Disulfiram (DSF) is a thiocarbamate based drug that has been approved for treating alcoholism for over 60 years. Preclinical studies have shown that DSF has anticancer efficacy, and its supplementation with copper (CuII) significantly potentiates the efficacy of DSF. However, the results of clinical trials have not yielded promising results. The elucidation of the anticancer mechanisms of DSF/Cu (II) will be beneficial in repurposing DSF as a new treatment for certain types of cancer. DSF's anticancer mechanism is primarily due to its generating reactive oxygen species, inhibiting aldehyde dehydrogenase (ALDH) activity inhibition, and decreasing the levels of transcriptional proteins. DSF also shows inhibitory effects in cancer cell proliferation, the self-renewal of cancer stem cells (CSCs), angiogenesis, drug resistance, and suppresses cancer cell metastasis. This review also discusses current drug delivery strategies for DSF alone diethyldithocarbamate (DDC), Cu (II) and DSF/Cu (II), and the efficacious component Diethyldithiocarbamate-copper complex (CuET).

Integrated machine learning and bioinformatic analyses used to construct a copper-induced cell death-related classifier for prognosis and immunotherapeutic response of hepatocellular carcinoma patients

Background: Copper as phytonutrient has powerful activity against health diseases. A newly discovered mechanism of cell death that affects energy metabolism by copper ("cuproptosis") can induce multiple cuproptosis-related genes. Hepatocellular carcinoma (HCC) is a poorly prognosed widespread cancer having danger of advanced metastasis. Therefore, earlier diagnosis followed by the specific targeted therapy are required for improved prognosis. The work herein constructed scoring system built on ten cuproptosis-related genes (CRGs) to predict progression of tumor and metastasis more accurately and test patient reaction toward immunotherapy. Methods: A comprehensive assessment of cuproptosis patterns in HCC samples from two databases and a real-world cohort was performed on ten CRGs, that were linked to immune cell infiltration signatures of TME (tumor microenvironment). Risk signatures were created for quantifying effect of cuproptosis on HCC, and the effects of related genes on cellular function of HCC were investigated, in addition to the effects of immunotherapy and targeted therapy drugs. Results: Two distinct cuproptosis-associated mutational patterns were identified, with distinct immune cell infiltration characteristics and survival likelihood. Studies have shown that assessment of cuproptosis-induced tumor mutational patterns can help predict tumor stage, phenotype, stromal activity, genetic diversity, and patient prognosis. High risk scores are characterized by lower survival and worse treatment with anti-PD-L1/CTAL4 immunotherapy and first-line targeted drugs. Cytological functional assays show that CDKN2A and GLS promote proliferation, migration and inhibit copper-dependent death of HCC cells. Conclusion: HCC patients with high-risk scores exhibit significant treatment disadvantage and survival rates. Cuproptosis plays a non-negligible role in the development of HCC. Quantifying cuproptosis-related designs of tumors will aid in phenotypic categorization, leading to efficient personalized and targeted therapeutics and precise prediction of prognosis and metastasis.

The molecular mechanisms of cuproptosis and its relevance to cardiovascular disease

Recently, cuproptosis has been demonstrated to be a new non-apototic cell death mode that is characterized by copper dependence and the regulation of mitochondrial respiration. Cuproptosis is distinct from known cell death modes such as apoptosis, necrosis, pyroptosis, or ferroptosis. Excessive copper induces cuproptosis by promoting protein toxic stress reactions via copper-dependent anomalous oligomerization of lipoylation proteins in the tricarboxylic acid (TCA) cycle and reducing iron-sulfur cluster protein levels. Ferredoxin1 (FDX1) promotes dihydrolipoyl transacetylase (DLAT) lipoacylation and abates iron-sulfur cluster proteins by reducing Cu²⁺ to Cu⁺, inducing cell death. Copper homeostasis depends on the copper transporter, and disturbances to this homeostasis cause cuproptosis. Recent evidence has shown that cuproptosis plays a significant role in the occurrence and development of many cardiovascular diseases, such as myocardial ischemia/reperfusion (I/R) injury, heart failure, atherosclerosis, and arrhythmias. Copper chelators, such as ammonium tetrathiomolybdate(VI) and DL-Penicillamine, may ease the above cardiovascular diseases by inhibiting the cuproptosis pathway. Oxidative phosphorylation inhibitors may inhibit cuproptosis by inhibiting protein stress response. In conclusion, cuproptosis plays an essential role in cardiovascular disease pathogenesis. Inhibition of cardiovascular cuproptosis is expected to become a potential treatment. Here, we will thoroughly review the molecular mechanisms involved in cuproptosis and its significance in cardiovascular disease.

Construction of prognostic risk model of bladder cancer based on cuproptosis-related long non-coding RNAs

OBJECTIVES

To construct a prognosis risk model based on long noncoding RNAs (lncRNAs) related to cuproptosis and to evaluate its application in assessing prognosis risk of bladder cancer patients.

METHODS

RNA sequence data and clinical data of bladder cancer patients were downloaded from the Cancer Genome Atlas database. The correlation between lncRNAs related to cuproptosis and bladder cancer prognosis was analyzed with Pearson correlation analysis, univariate Cox regression, Lasso regression, and multivariate Cox regression. Then a cuproptosis-related lncRNA prognostic risk scoring equation was constructed. Patients were divided into high-risk and low-risk groups based on the median risk score, and the immune cell abundance between the two groups were compared. The accuracy of the risk scoring equation was evaluated using Kaplan-Meier survival curves, and the application of the risk scoring equation in predicting 1, 3 and 5-year survival rates was evaluated using receiver operating characteristic (ROC) curves. Univariate and multivariate Cox regression were used to screen for prognostic factors related to bladder cancer patients, and a prognostic risk assessment nomogram was constructed, the accuracy of which was evaluated with calibration curves.

RESULTS

A prognostic risk scoring equation for bladder cancer patients was constructed based on nine cuproptosis-related lncRNAs. Immune infiltration analysis showed that the abundances of M0 macrophages, M1 macrophages, M2 macrophages, resting mast cells and neutrophils in the high-risk group were significantly higher than those in the low-risk group, while the abundances of CD8+ T cells, helper T cells, regulatory T cells and plasma cells in the low-risk group were significantly higher than those in the high-risk group (all P<0.05). Kaplan-Meier survival curve analysis showed that the total survival and progression-free survival of the low-risk group were longer than those of the high-risk group (both P<0.01). Univariate and multivariate Cox analysis showed that the risk score, age and tumor stage were independent factors for patient prognosis. The ROC curve analysis showed that the area under the curve (AUC) of the risk score in predicting 1, 3 and 5-year survival was 0.716, 0.697 and 0.717, respectively. When combined with age and tumor stage, the AUC for predicting 1-year prognosis increased to 0.725. The prognostic risk assessment nomogram for bladder cancer patients constructed based on patient age, tumor stage, and risk score had a prediction value that was consistent with the actual value.

CONCLUSIONS

A bladder cancer patient prognosis risk assessment model based on cuproptosis-related lncRNA has been successfully constructed in this study. The model can predict the prognosis of bladder cancer patients and their immune infiltration status, which may also provide a reference for tumor immunotherapy.

Photothermally Triggered Copper Payload Release for Cuproptosis-Promoted Cancer Synergistic Therapy

Cuproptosis is a new form of programmed cell death and exhibits enormous potential in cancer treatment. However, reducing the undesirable Cu ion release in normal tissue and maximizing the copper-induced therapeutic effect in cancer sites are two main challenges. In this study, we constructed a photothermally triggered nanoplatform (Au@MSN-Cu/PEG/DSF) to realize on-demand delivery for synergistic therapy. The released disulfiram (DSF) chelated with Cu²⁺ in situ to generate highly cytotoxic bis(diethyldithiocarbamate)copper (CuET), causing cell apoptosis, and the formed Cu⁺ species promoted toxic mitochondrial protein aggregation, leading to cell cuproptosis. Synergistic with photothermal therapy, Au@MSN-Cu/PEG/DSF could effectively kill tumor cells and inhibit tumor growth (inhibition rate up to 80.1 %). These results provide a promising perspective for potential cancer treatment based on cuproptosis, and may also inspire the design of advanced nano-therapeutic platforms.

Cuproptosis: mechanisms and links with cancers

Cuproptosis was a copper-dependent and unique kind of cell death that was separate from existing other forms of cell death. The last decade has witnessed a considerable increase in investigations of programmed cell death, and whether copper induced cell death was an independent form of cell death has long been argued until mechanism of cuproptosis has been revealed. After that, increasing number of researchers attempted to identify the relationship between cuproptosis and the process of cancer. Thus, in this review, we systematically detailed the systemic and cellular metabolic processes of copper and the copper-related tumor signaling pathways. Moreover, we not only focus on the discovery process of cuproptosis and its mechanism, but also outline the association between cuproptosis and cancers. Finally, we further highlight the possible therapeutic direction of employing copper ion ionophores with cuproptosis-inducing functions in combination with small molecule drugs for targeted therapy to treat specific cancers.

Identification and characterisation of the tegument-expressed aldehyde dehydrogenase SmALDH_312 of Schistosoma mansoni, a target of disulfiram

Schistosomiasis is an infectious disease caused by blood flukes of the genus Schistosoma and affects approximately 200 million people worldwide. Since Praziquantel (PZQ) is the only drug for schistosomiasis, alternatives are needed. By a biochemical approach, we identified a tegumentally expressed aldehyde dehydrogenase (ALDH) of S. mansoni, SmALDH_312. Molecular analyses of adult parasites showed Smaldh_312 transcripts in both genders and different tissues. Physiological and cell-biological experiments exhibited detrimental effects of the drug disulfiram (DSF), a known ALDH inhibitor, on larval and adult schistosomes in vitro. DSF also reduced stem-cell proliferation and caused severe tegument damage in treated worms. In silico-modelling of SmALDH_312 and docking analyses predicted DSF binding, which we finally confirmed by enzyme assays with recombinant SmALDH_312. Furthermore, we identified compounds of the Medicine for Malaria Venture (MMV) pathogen box inhibiting SmALDH_312 activity. Our findings represent a promising starting point for further development towards new drugs for schistosomiasis.

Pan-cancer analyses reveal molecular and clinical characteristics of cuproptosis regulators

Imbalance in copper homeostasis can be lethal. A recent study found that excess copper induces cell death in a way that has never been characterized before, which is dependent on mitochondrial stress and is referred to as "cuproptosis." The role of cuproptosis in tumors has not yet been elucidated. In this study, we revealed the complex and important roles of cuproptosis regulators and cuproptosis activity in tumors via a comprehensive analysis of multiomics data from more than 10,000 samples of 33 tumor types. We found that the cyclin-dependent kinase inhibitor 2A is the most frequently altered cuproptosis regulator, and the cuproptosis regulator expression is dysregulated in various tumors. Additionally, we developed a cuproptosis activity score to reflect the overall cuproptosis level. On the basis of the expression levels of cuproptosis regulators, tumors can be divided into two clusters with different cuproptosis activities and survival outcomes. Importantly, cuproptosis activity was found to be associated with the prognosis of multiple tumors and multiple tumor-related pathways, including fatty acid metabolism and remodeling of the tumor microenvironment. Furthermore, cuproptosis increased the sensitivity to multiple drugs and exhibited potential to predict the outcome of immunotherapy. We also comprehensively identified cuproptosis-related microRNAs, long noncoding RNAs, and transcription factors. We provided the code corresponding to the results of this study in GitHub (https://github.com/Changwuuu/Cuproptosis-pancancer.git) for reference. In summary, this study reveals important molecular and clinical characteristics of cuproptosis regulators and cuproptosis activity in tumors, and suggests the use of cuproptosis as a promising tumor therapeutic approach. This study provides an important reference point for future cuproptosis-related research.

Molecular subtypes based on cuproptosis-related genes and tumor microenvironment infiltration characteristics in pancreatic adenocarcinoma

BACKGROUND

Multiple molecular subtypes with distinct clinical outcomes in pancreatic adenocarcinoma (PAAD) have been identified in recent years. Cuproptosis is a new form of cell death that likely involved in tumor progression. However, the cuproptosis-related molecular subtypes as well as its mediated tumor microenvironment (TME) cell infiltration characteristics largely remain unclear.

METHODS

Expression profiles of 10 cuproptosis-related genes (CRGs) and their association with patient survival, TME, cancer stemness and drug resistance were studied in 33 cancer types using the TCGA pan-cancer data. Using 437 PAAD samples from five cohorts (TCGA-PAAD cohort and four GEO cohorts), we explored the molecular subtypes mediated by CRGs, along with the associated TME cell infiltration. Unsupervised methods were utilized to perform cuproptosis subtype clustering. The cuproptosis score was constructed using the COX regression model with least absolute shrinkage and selection operator regression (LASSO) algorithm to quantify the cuproptosis characteristics of a single tumor.

RESULTS

The expression of 10 CRGs varies in different cancer types with striking inter- and intra- cancer heterogeneity. We integrated the genomic profiling of the CRGs and identified three distinct cuproptosis subtypes, and found that multi-layer CRG alterations were correlated with patient prognosis and TME cell infiltration characteristics. In addition, a cuproptosis score signature was constructed to predict prognosis, and its clinical impacts were characterized in the TCGA-PAAD cohort. The cuproptosis signature was significantly associated with prognosis, tumor subtypes, CD8 T-cell infiltration, response to immune checkpoint inhibitors (ICIs) and chemotherapeutic drug sensitivity. Furthermore, the expression patterns of CRGs in pancreatic cancer cells and normal controls were validated, which was almost consistent with the results from the public database. The expression level and prognostic predictive capability of DLAT were verified in 97 PAAD patients from our patient cohort.

CONCLUSIONS

These findings may help understand the roles of CRGs in PAAD and the molecular characterization of cuproptosis subtypes. In addition, the cuproptosis score could serve as a promising biomarker for predicting prognosis and response to immunotherapy in PAAD patients.

A novel prognostic scoring model based on copper homeostasis and cuproptosis which indicates changes in tumor microenvironment and affects treatment response

Background: Intracellular copper homeostasis requires a complex system. It has shown considerable prospects for intervening in the tumor microenvironment (TME) by regulating copper homeostasis and provoking cuproptosis. Their relationship with hepatocellular carcinoma (HCC) remains elusive. Methods: In TCGA and ICGC datasets, LASSO and multivariate Cox regression were applied to obtain the signature on the basis of genes associated with copper homeostasis and cuproptosis. Bioinformatic tools were utilized to reveal if the signature was correlated with HCC characteristics. Single-cell RNA sequencing data analysis identified differences in tumor and T cells' pathway activity and intercellular communication of immune-related cells. Real-time qPCR analysis was conducted to measure the genes' expression in HCC and adjacent normal tissue from 21 patients. CCK8 assay, scratch assay, transwell, and colony formation were conducted to reveal the effect of genes on in vitro cell proliferation, invasion, migration, and colony formation. Results: We constructed a five-gene scoring system in relation to copper homeostasis and cuproptosis. The high-risk score indicated poor clinical prognosis, enhanced tumor malignancy, and immune-suppressive tumor microenvironment. The T cell activity was markedly reduced in high-risk single-cell samples. The high-risk HCC patients had a better expectation of ICB response and reactivity to anti-PD-1 therapy. A total of 156 drugs were identified as potential signature-related drugs for HCC treatment, and most were sensitive to high-risk patients. Novel ligand-receptor pairs such as FASLG, CCL, CD40, IL2, and IFN-Ⅱ signaling pathways were revealed as cellular communication bridges, which may cause differences in TME and immune function. All crucial genes were differentially expressed between HCC and paired adjacent normal tissue. Model-constructed genes affected the phosphorylation of mTOR and AKT in both Huh7 and Hep3B cells. Knockdown of ZCRB1 impaired the proliferation, invasion, migration, and colony formation in HCC cell lines. Conclusion: We obtained a prognostic scoring system to forecast the TME changes and assist in choosing therapy strategies for HCC patients. In this study, we combined copper homeostasis and cuproptosis to show the overall potential risk of copper-related biological processes in HCC for the first time.

Identification of cuproptosis-related lncRNAs for prognosis and immunotherapy in glioma

Glioma is a highly invasive primary brain tumour, making it challenging to accurately predict prognosis for glioma patients. Cuproptosis is a recently discovered cell death attracting significant attention in the tumour field. Whether cuproptosis-related genes have prognostic predictive value has not been clarified. In this study, uni-/multi-variate Cox and Lasso regression analyses were applied to construct a risk model based on cuproptosis-related lncRNAs using TCGA and CGGA cohorts. A nomogram was constructed to quantify individual risk, including clinical and genic characteristics and risk. GO and KEGG analyses were used to define functional enrichment of DEGs. Tumour mutation burden (TMB) and immune checkpoint analyses were performed to evaluate potential responses to ICI therapy. Ten prognostic lncRNAs were obtained from Cox regression. Based on the median risk score, patients were divided into high- and low-risk groups. Either for grade 2-3 or for grade 4, glioma patients with high-risk exhibited significant poorer prognoses. The risk was an independent risk factor associated with overall survival. The high-risk group was functionally associated with immune responses and cancer-related pathways. The high-risk group was associated with higher TMB scores. The expression levels of many immune checkpoints in the high-risk group were significantly higher than those in the low-risk group. Differentiated immune pathways were primarily enriched in the IFN response, immune checkpoint and T-cell co-stimulation pathways. In conclusion, we established a risk model based on cuproptosis-related lncRNAs showing excellent prognostic prediction ability but also indicating the immuno-microenvironment status of glioma.

Copper homeostasis and cuproptosis in health and disease

As an essential micronutrient, copper is required for a wide range of physiological processes in virtually all cell types. Because the accumulation of intracellular copper can induce oxidative stress and perturbing cellular function, copper homeostasis is tightly regulated. Recent studies identified a novel copper-dependent form of cell death called cuproptosis, which is distinct from all other known pathways underlying cell death. Cuproptosis occurs via copper binding to lipoylated enzymes in the tricarboxylic acid (TCA) cycle, which leads to subsequent protein aggregation, proteotoxic stress, and ultimately cell death. Here, we summarize our current knowledge regarding copper metabolism, copper-related disease, the characteristics of cuproptosis, and the mechanisms that regulate cuproptosis. In addition, we discuss the implications of cuproptosis in the pathogenesis of various disease conditions, including Wilson's disease, neurodegenerative diseases, and cancer, and we discuss the therapeutic potential of targeting cuproptosis.

Iron-Sulfur Clusters: A Key Factor of Regulated Cell Death in Cancer

Iron-sulfur clusters are ancient cofactors that play crucial roles in myriad cellular functions. Recent studies have shown that iron-sulfur clusters are closely related to the mechanisms of multiple cell death modalities. In addition, numerous previous studies have demonstrated that iron-sulfur clusters play an important role in the development and treatment of cancer. This review first summarizes the close association of iron-sulfur clusters with cell death modalities such as ferroptosis, cuprotosis, PANoptosis, and apoptosis and their potential role in cancer activation and drug resistance. This review hopes to generate new cancer therapy ideas and overcome drug resistance by modulating iron-sulfur clusters.

Pan-cancer genetic analysis of cuproptosis and copper metabolism-related gene set

Background

A recent paper has revealed a novel cell death pathway, cuproptosis, a programmed cell death based on copper. This study aimed to evaluate the pan-cancer genomics and clinical association of cuproptosis and copper metabolism-related cell death genes, including SLC25A3, SLC25A37, SLC31A1, FDX1, DLAT, LIAS, ATP7A, ATP7B, COX17, SCO1, SCO2, COX11, and COX19.

Methods

By mining multi-omics profiling data, we performed a comprehensive and systematic characterization of cuproptosis genes across more than 9,000 samples of over 30 types of cancer.

Results

ATP7B and ATP7A were the two most frequently mutated copper cell death genes in cancer. UCEC and SKCM were the two cancer types that have the highest mutation rates while the mutation of LIAS was associated with worse survival of BRCA. Brain cancer was potentially affected by copper cell death because of the difference in copper cell death gene expression among subtypes and stages. On the contrary, KIRC might have a lower cuproptosis activity because of the decrease in copper cell death gene expression. In lung cancer and kidney cancer, most of the cancer–noncancer expression patterns of copper cell death genes were consistent between mRNA and protein levels. Some of the cuproptosis gene expression was associated with the survival of LGG, KIRC, and ACC. The top five expression-copy numbers correlating cancer types were BRCA, OV, LUSC, HNSC, BLCA, and LUAD. Generally, the copy number variations of these genes in KIRC, UCEC, and LGG were associated with survival. The expression of DLAT, LIAS, and ATP7B was negatively correlated with the methylation in most of the cancer types. The copper cell death genes regulating miRNA and pathway regulation networks were constructed. The copper cell death genes were correlated with immune cell infiltration levels of multiple immune cells. These genes were correlated with the sensitivity of cancer cells to multiple drugs.

Conclusion

Copper cell death genes are potentially involved in many cancer types and can be developed as candidates for cancer diagnosis, prognosis, and therapeutic biomarkers.

Comprehensive investigation into cuproptosis in the characterization of clinical features, molecular characteristics, and immune situations of clear cell renal cell carcinoma

Background

Copper-induced cell death has been widely investigated in human diseases as a form of programmed cell death (PCD). The newly recognized mechanism underlying copper-induced cell death provided us creative insights into the copper-related toxicity in cells, and this form of PCD was termed cuproptosis.

Methods

Through consensus clustering analysis, ccRCC patients from TCGA database were classified into different subgroups with distinct cuproptosis-based molecular patterns. Analyses of clinical significance, long-term survival, and immune features were performed on subgroups accordingly. The cuproptosis-based risk signature and nomogram were constructed and validated relying on the ccRCC cohort as well. The cuproptosis scoring system was generated to better characterize ccRCC patients. Finally, in vitro validation was conducted using ccRCC clinical samples and cell lines.

Result

Patients from different subgroups displayed diverse clinicopathological features, survival outcomes, tumor microenvironment (TME) characteristics, immune-related score, and therapeutic responses. The prognostic model and cuproptosis score were well validated and proved to efficiently distinguish the high risk/score and low risk/score patients, which revealed the great predictive value. The cuproptosis score also tended out to be intimately associated with the prognosis and immune features of ccRCC patients. Additionally, the hub cuproptosis-associated gene (CAG) FDX1 presented a dysregulated expression pattern in human ccRCC samples, and it was confirmed to effectively promote the killing effects of copper ionophore elesclomol as a direct target. In vitro functional assays revealed the prominent anti-cancer role of FDX1 in ccRCC.

Conclusion

Cuproptosis played an indispensable role in the regulation of TME features, tumor progression, and long-term prognosis of ccRCC.

Cuproptosis patterns in papillary renal cell carcinoma are characterized by distinct tumor microenvironment infiltration landscapes

Cuproptosis is a novel kind of programmed cell death that has been linked to tumor development, prognosis, and responsiveness to therapy. Nevertheless, the precise function of cuproptosis-related genes (CRGs) in the tumor microenvironment (TME) remains unknown. We characterized the genetic and transcriptional changes of CRGs in papillary renal cell carcinoma (PRCC) samples and analyzed the expression patterns in two separate cohorts. We observed that two unique cuproptosis-related subgroups and three separate gene subgroups were connected with clinicopathological, prognostic, and TME features of patients. Then, a risk score for predicting overall survival (OS) was created and validated in patients with PRCC. To make the risk score more clinically useful, we created a nomogram that was very accurate. A lower risk score, which was associated with higher tumor mutation burden, and immune activity, suggested a better prognosis for OS. Additionally, the risk score was shown to be substantially linked with the drug’s susceptibility to chemotherapeutic agents. Our extensive research of CRGs in PRCC identified possible roles for them in the TME, clinicopathological features, and overall survival. These findings may help advance our knowledge of CRGs in PRCC and pave the way for improved prognosis and the creation of more effective immunotherapy therapies.

Prognostic Implication of a Cuproptosis-Related miRNA Signature in Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most frequently diagnosed malignancies globally, accounting for the third cause of cancer mortality. Cuproptosis, a copper-induced cell death, was recently reported in Science. The purpose of this study was to evaluate the prognostic implication of cuproptosis-related miRNAs (CRMs) in HCC.

Methods

Transcriptomic data and clinicopathological features of patients with HCC were extracted from the Cancer Genome Atlas (TCGA) database. Prognostic CRM signature was established by utilizing univariate Cox regression and LASSO analyses. To validate the accuracy of prediction, the Kaplan-Meier (K-M) and time-dependent receiver operating characteristic (ROC) analyses were adopted. A nomogram comprising clinical characteristics and the miRNA signature was developed to improve the prediction of patient outcomes. Finally, functional enrichment analysis and immune infiltration analysis were carried out.

Results

Of CRMs, 14 were obtained to construct a prognostic miRNA signature. This CRM signature was an independent factor for predicting overall survival (OS). Kaplan-Meier curves demonstrated a noteworthy difference in survival rates between different risk subgroups (p < 0.001). The robust prognostic capacity of this signature was exhibited by sampling verification and stratified survival analysis. Functional analysis indicated that the high-risk group was mainly enriched in signaling pathways and different levels of immune infiltration were revealed between the two risk groups. The potential interaction of the model with the immune checkpoint activities was also detected.

Conclusion

The CRM signature could act as an independent predictor to guide individual treatment strategies, which could provide fundamental insights for further studies.

Cuproptosis-Related Risk Score Predicts Prognosis and Characterizes the Tumor Microenvironment in Hepatocellular Carcinoma

Aims

Cuproptosis is a recently identified form of programmed cell death; however, its role in hepatocellular carcinoma (HCC) remains unclear.

Methods

A set of bioinformatic tools was integrated to analyze the expression and prognostic significance of ferredoxin 1 (FDX1), the key regulator of cuproptosis. A cuproptosis-related risk score (CRRS) was developed via correlation analyses, least absolute shrinkage and selection operator (LASSO) Cox regression, and multivariate Cox regression. The metabolic features, mutation signatures, and immune profile of CRRS-classified HCC patients were investigated, and the role of CRRS in therapy guidance was analyzed.

Results

FDX1 was significantly downregulated in HCC, and its high expression was associated with longer survival time. HCC patients in the high-CRRS group showed a significantly lower overall survival (OS) and enriched in cancer-related pathways. Mutation analyses revealed that the high-CRRS HCC patients had a high mutational frequency of some tumor suppressors such as tumor protein P53 (TP53) and Breast-cancer susceptibility gene 1 (BRCA1)-associated protein 1 (BAP1) and a low frequency of catenin beta 1 (CTNNB1). Besides, HCC patients with high CRRS showed an increase of protumor immune infiltrates and a high expression of immune checkpoints. Moreover, the area under the curve (AUC) values of CRRS in predicting the efficiency of sorafenib and the non-responsiveness to transcatheter arterial chemoembolization (TACE) in HCC patients reached 0.877 and 0.764, respectively.

Significance

The cuproptosis-related signature is helpful in prognostic prediction and in guiding treatment for HCC patients.

Cytotoxic effect of disulfiram/copper on human cervical cancer cell lines and LGR5-positive cancer stem-like cells

BACKGROUND

Tumor resistance is a global challenge for tumor treatment. Cancer stem cells (CSCs) are the main population of tumor cells for drug resistance. We have reported that high aldehyde dehydrogenase (ALDH) activity represents a functional marker for cervical CSCs. Here, we aimed at disulfiram (DSF), an ALDH inhibitor, that has the potential to be used for cervical cancer treatment.

METHODS

MTT assay, western blot, vector construction and transfection, cell sorting and in vivo anti-tumor assays were performed using cervical cancer cell lines SiHa and HeLa. Cell cycle distribution and cell apoptosis were carried out by flow cytometry. The cytotoxicity of DSF was detected by MTT assay and cervical cancer xenograft models.

RESULTS

DSF was cytotoxic to cervical cancer cell lines in a copper (Cu)-dependent manner. Disulfiram/copper (DSF/Cu) complex induced deregulation of S-phase and inhibited the expression of stemness markers in cervical cancer cells. Furthermore, DSF/Cu could also reduce the cancer stem cell-like LGR5⁺ cells which lead to cisplatin resistance in cervical cancer cells. DSF/Cu complex had the greater antitumor efficacy on cervical cancer than cisplatin in vitro and in vivo.

CONCLUSION

Our findings indicate that the cytotoxicity of DSF/Cu complex may be superior to cisplatin because of targeting LGR5-positive cervical cancer stem-like cells in cervical cancer. Thus, the DSF/Cu complex may represent a potential therapeutic strategy for cervical cancer patients.

Programming Hydrogels with Complex Transient Behaviors via Autocatalytic Cascade Reactions

It is challenging to design complex synthetic life-like systems that can show both autoevolution and fuel-driven transient behaviors. Here, we report a new class of chemical reaction networks (CRNs) to construct life-like polymer hydrogels. The CRNs are constituted of autocatalytic cascade reactions and fuel-driven reaction networks. The reactions start with only two compounds, that is, thiol of 4-arm-PEG-SH and thiuram disulfides, and undergo thiol oxidation (k₁), disulfide metathesis (k₂), and thionate hydrolysis-coupling reactions (k₃) subsequently, leading to a four-state autonomous transition of sol(I) → soft gel → sol(II) → stiff gel. Moreover, thiuram disulfides can be applied as a fuel to drive the repeated occurrence of metathesis and hydrolysis-coupling reactions, generating dissipative stiff gel → sol(II) → stiff gel cycles. Systematic kinetics studies reveal that the event and lifetime of every transient state could be delicately tailored-up by varying the thiuram disulfide concentration, pH of the system, and thiuram structures. Since the consecutive transient behaviors are precisely predictable, we envision the strategy's potential in guiding the molecular designs of autonomous and adaptive materials for many fields.