Disulfiram/copper selectively eradicates AML leukemia stem cells in vitro and in vivo by simultaneous induction of ROS-JNK and inhibition of NF-κB and Nrf2

Disulfiram: A novel repurposed drug for cancer therapy

ABSTRACT

Cancer is a major global health issue. Effective therapeutic strategies can prolong patients' survival and reduce the costs of treatment. Drug repurposing, which identifies new therapeutic uses for approved drugs, is a promising approach with the advantages of reducing research costs, shortening development time, and increasing efficiency and safety. Disulfiram (DSF), a Food and Drug Administration (FDA)-approved drug used to treat chronic alcoholism, has a great potential as an anticancer drug by targeting diverse human malignancies. Several studies show the antitumor effects of DSF, particularly the combination of DSF and copper (DSF/Cu), on a wide range of cancers such as glioblastoma (GBM), breast cancer, liver cancer, pancreatic cancer, and melanoma. In this review, we summarize the antitumor mechanisms of DSF/Cu, including induction of intracellular reactive oxygen species (ROS) and various cell death signaling pathways, and inhibition of proteasome activity, as well as inhibition of nuclear factor-kappa B (NF-κB) signaling. Furthermore, we highlight the ability of DSF/Cu to target cancer stem cells (CSCs), which provides a new approach to prevent tumor recurrence and metastasis. Strikingly, DSF/Cu inhibits several molecular targets associated with drug resistance, and therefore it is becoming a novel option to increase the sensitivity of chemo-resistant and radio-resistant patients. Studies of DSF/Cu may shed light on its improved application to clinical tumor treatment.

Bidirectional relationship between pancreatic cancer and diabetes mellitus: a comprehensive literature review

Pancreatic cancer (PC) is a fatal malignant disease. It is well known that the relationship between PC and type 2 diabetes mellitus (T2DM) is a complicated bidirectional relationship. The most important factors causing increased risks of pancreatic cancer are hyperglycaemia, hyperinsulinemia, pancreatitis, and dyslipidemia. Genetics and the immune system also play an important role in the relationship between diabetes mellitus and pancreatic cancer. The primary contributors to this association involve insulin resistance and inflammatory processes within the tumour microenvironment. The combination of diabetes and obesity can contribute to PC by inducing hyperinsulinemia and influencing leptin and adiponectin levels. Given the heightened incidence of pancreatic cancer in diabetes patients compared to the general population, early screening for pancreatic cancer is recommended. Diabetes negatively impacts the survival of pancreatic cancer patients. Among patients receiving chemotherapy, it reduced their survival. The implementation of a healthy lifestyle, including weight management, serves as an initial preventive measure to mitigate the risk of disease development. The role of anti-diabetic drugs on survival is controversial; however, metformin may have a positive impact, especially in the early stages of cancer, while insulin therapy increases the risk of PC.

Localized Sustained Release of Copper Enhances Antitumor Effects of Disulfiram in Head and Neck Cancer

Drug repurposing uses approved drugs as candidate anticancer therapeutics, harnesses previous research and development efforts, and benefits from available clinically suitable formulations and evidence of patient tolerability. In this work, the drug used clinically to treat chronic alcoholism, disulfiram (DSF), was studied for its antitumor efficacy in a copper-dependent manner. The combination of DSF and copper could achieve a tumor cell growth inhibition effect comparable to those of 5-fluorouracil and taxol on head and neck cancer cells. Both bulk dendrimer hydrogel and microsized dendrimer hydrogel particles were utilized for the localized sustained release of copper in the tumor site. The localized sustained release of copper facilitated the tumor inhibition effect following intratumoral injection in a mouse's head and neck cancer model.

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.

SF3B1 mutations provide genetic vulnerability to copper ionophores in human acute myeloid leukemia

In a phenotypical screen of 56 acute myeloid leukemia (AML) patient samples and using a library of 10,000 compounds, we identified a hit with increased sensitivity toward SF3B1-mutated and adverse risk AMLs. Through structure-activity relationship studies, this hit was optimized into a potent, specific, and nongenotoxic molecule called UM4118. We demonstrated that UM4118 acts as a copper ionophore that initiates a mitochondrial-based noncanonical form of cell death known as cuproptosis. CRISPR-Cas9 loss-of-function screen further revealed that iron-sulfur cluster (ISC) deficiency enhances copper-mediated cell death. Specifically, we found that loss of the mitochondrial ISC transporter ABCB7 is synthetic lethal to UM4118. ABCB7 is misspliced and down-regulated in SF3B1-mutated leukemia, creating a vulnerability to copper ionophores. Accordingly, ABCB7 overexpression partially rescued SF3B1-mutated cells to copper overload. Together, our work provides mechanistic insights that link ISC deficiency to cuproptosis, as exemplified by the high sensitivity of SF3B1-mutated AMLs. We thus propose SF3B1 mutations as a biomarker for future copper ionophore-based therapies.

Aberrant Lipid Metabolic Signatures in Acute Myeloid Leukemia

Leukemogenesis is a complex process that involves multiple stages of mutation in either hematopoietic stem or progenitor cells, leading to cancer development over time. Acute myeloid leukemia (AML) is an aggressive malignancy that affects myeloid cells. The major disease burden is caused by immature blast cells, which are eliminated using conventional chemotherapies. Unfortunately, relapse is a leading cause of death in AML patients, with 30%-80% experiencing it within 2 years of initial treatment. The dominant cause of relapse in leukemia is the presence of therapy-resistant leukemic stem cells (LSCs). These cells express genes related to stemness that are frequently difficult to eradicate and tend to survive standard treatments. Studies have demonstrated that by targeting the metabolic pathways of LSCs, it is possible to improve outcomes and extend the survival of those afflicted by leukemia. The overwhelming evidence suggests that lipid metabolism is reprogrammed in LSCs, leading to an increase in fatty acid uptake and de novo lipogenesis. Genes regulating this process also play a crucial role in therapy evasion. In this concise review, we summarize the lipid metabolism in normal hematopoietic cells, AML blast cells, and AML LSCs. We also compare the lipid metabolic signatures in de novo versus therapy-resistant AML blast and LSCs. We further discuss the metabolic switches, cellular crosstalk, potential targets, and inhibitors of lipid metabolism that could alleviate treatment resistance and relapse.

Hyperbaric Oxygen Boosts Antitumor Efficacy of Copper-Diethyldithiocarbamate Nanoparticles against Pancreatic Ductal Adenocarcinoma by Regulating Cancer Stem Cell Metabolism

Cuproptosis-based cancer nanomedicine has received widespread attention recently. However, cuproptosis nanomedicine against pancreatic ductal adenocarcinoma (PDAC) is severely limited by cancer stem cells (CSCs), which reside in the hypoxic stroma and adopt glycolysis metabolism accordingly to resist cuproptosis-induced mitochondria damage. Here, we leverage hyperbaric oxygen (HBO) to regulate CSC metabolism by overcoming tumor hypoxia and to augment CSC elimination efficacy of polydopamine and hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanoparticles (CuET@PH NPs). Mechanistically, while HBO and CuET@PH NPs inhibit glycolysis and oxidative phosphorylation, respectively, the combination of HBO and CuET@PH NPs potently suppresses energy metabolism of CSCs, thereby achieving robust tumor inhibition of PDAC and elongating mice survival importantly. This study reveals novel insights into the effects of cuproptosis nanomedicine on PDAC CSC metabolism and suggests that the combination of HBO with cuproptosis nanomedicine holds significant clinical translation potential for PDAC patients.

The effect of lipid metabolism on cuproptosis-inducing cancer therapy

Cuproptosis provides a new therapeutic strategy for cancer treatment and is thought to have broad clinical application prospects. Nevertheless, some oncological clinical trials have yet to demonstrate favorable outcomes, highlighting the need for further research into the molecular mechanisms underlying cuproptosis in tumors. Cuproptosis primarily hinges on the intracellular accumulation of copper, with lipid metabolism exerting a profound influence on its course. The interaction between copper metabolism and lipid metabolism is closely related to cuproptosis. Copper imbalance can affect mitochondrial respiration and lipid metabolism changes, while lipid accumulation can promote copper uptake and absorption, and inhibit cuproptosis induced by copper. Anomalies in lipid metabolism can disrupt copper homeostasis within cells, potentially triggering cuproptosis. The interaction between cuproptosis and lipid metabolism regulates the occurrence, development, metastasis, chemotherapy drug resistance, and tumor immunity of cancer. Cuproptosis is a promising new target for cancer treatment. However, the influence of lipid metabolism and other factors should be taken into consideration. This review provides a brief overview of the characteristics of the interaction between cuproptosis and lipid metabolism in cancer and analyses potential strategies of applying cuproptosis for cancer treatment.

Research progress on cuproptosis in cancer

Cuproptosis is a recently discovered form of cell death that is mediated by copper (Cu) and is a non-apoptotic form of cell death related to oligomerization of lipoylated proteins and loss of Fe-S protein clusters. Since its discovery, cuproptosis has been extensively studied by researchers for its mechanism and potential applications in the treatment of cancer. Therefore, this article reviews the specific mechanism of cuproptosis currently studied, as well as its principles and strategies for use in anti-cancer treatment, with the aim of providing a reference for cuproptosis-based cancer therapy.

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.

Cuproptosis: A novel therapeutic target for overcoming cancer drug resistance

Cuproptosis is a newly identified form of cell death driven by copper. Recently, the role of copper and copper triggered cell death in the pathogenesis of cancers have attracted attentions. Cuproptosis has garnered enormous interest in cancer research communities because of its great potential for cancer therapy. Copper-based treatment exerts an inhibiting role in tumor growth and may open the door for the treatment of chemotherapy-insensitive tumors. In this review, we provide a critical analysis on copper homeostasis and the role of copper dysregulation in the development and progression of cancers. Then the core molecular mechanisms of cuproptosis and its role in cancer is discussed, followed by summarizing the current understanding of copper-based agents (copper chelators, copper ionophores, and copper complexes-based dynamic therapy) for cancer treatment. Additionally, we summarize the emerging data on copper complexes-based agents and copper ionophores to subdue tumor chemotherapy resistance in different types of cancers. We also review the small-molecule compounds and nanoparticles (NPs) that may kill cancer cells by inducing cuproptosis, which will shed new light on the development of anticancer drugs through inducing cuproptosis in the future. Finally, the important concepts and pressing questions of cuproptosis in future research that should be focused on were discussed. This review article suggests that targeting cuproptosis could be a novel antitumor therapy and treatment strategy to overcome cancer drug resistance.

Targeting the NF-E2-related factor 2 pathway for overcoming leukemia

Leukemia is cancer of the body's blood-forming tissues, including the bone marrow and the lymphatic system. There are many types of leukemia that some of them occur in children and the others are more common in adults. Currently, there are many different chemotherapy agents for leukemia while chemoresistance increases the survival of the leukemic cells. One of the main reasons of chemoresistance, is a transcription factor called Nuclear factor erythroid 2-Related Factor 2 (NRF2). An increase in NRF2 expression in leukemic cells which are being treated with chemotherapy agents, can increase the survival of these cells in the presence of therapeutics. Accordingly, the inhibition of NRF2 by different methods as a cotreatment with classical chemotherapy agents, can be a promising procedure in leukemia treatment. In this study we focus on the association of NRF2 and leukemia and targeting it as a new therapeutic method in leukemia treatment.

Copper in Gynecological Diseases

Copper (Cu) is an essential micronutrient for the correct development of eukaryotic organisms. This metal plays a key role in many cellular and physiological activities, including enzymatic activity, oxygen transport, and cell signaling. Although the redox activity of Cu is crucial for enzymatic reactions, this property also makes it potentially toxic when found at high levels. Due to this dual action of Cu, highly regulated mechanisms are necessary to prevent both the deficiency and the accumulation of this metal since its dyshomeostasis may favor the development of multiple diseases, such as Menkes' and Wilson's diseases, neurodegenerative diseases, diabetes mellitus, and cancer. As the relationship between Cu and cancer has been the most studied, we analyze how this metal can affect three fundamental processes for tumor progression: cell proliferation, angiogenesis, and metastasis. Gynecological diseases are characterized by high prevalence, morbidity, and mortality, depending on the case, and mainly include benign and malignant tumors. The cellular processes that promote their progression are affected by Cu, and the mechanisms that occur may be similar. We analyze the crosstalk between Cu deregulation and gynecological diseases, focusing on therapeutic strategies derived from this metal.

ALDEFLUOR activity, ALDH isoforms, and their clinical significance in cancers

High aldehyde dehydrogenase (ALDH) activity is a metabolic feature of adult stem cells and various cancer stem cells (CSCs). The ALDEFLUOR system is currently the most commonly used method for evaluating ALDH enzyme activity in viable cells. This system is applied extensively in the isolation of normal stem cells and CSCs from heterogeneous cell populations. For many years, ALDH1A1 has been considered the most important subtype among the 19 ALDH family members in determining ALDEFLUOR activity. However, in recent years, studies of many types of normal and tumour tissues have demonstrated that other ALDH subtypes can also significantly influence ALDEFLUOR activity. In this article, we briefly review the relationships between various members of the ALDH family and ALDEFLUOR activity. The clinical significance of these ALDH isoforms in different cancers and possible directions for future studies are also summarised.

Aldehyde Dehydrogenase Genes as Prospective Actionable Targets in Acute Myeloid Leukemia

It has been previously shown that the aldehyde dehydrogenase (ALDH) family member ALDH1A1 has a significant association with acute myeloid leukemia (AML) patient risk group classification and that AML cells lacking ALDH1A1 expression can be readily killed via chemotherapy. In the past, however, a redundancy between the activities of subgroup members of the ALDH family has hampered the search for conclusive evidence to address the role of specific ALDH genes. Here, we describe the bioinformatics evaluation of all nineteen member genes of the ALDH family as prospective actionable targets for the development of methods aimed to improve AML treatment. We implicate ALDH1A1 in the development of recurrent AML, and we show that from the nineteen members of the ALDH family, ALDH1A1 and ALDH2 have the strongest association with AML patient risk group classification. Furthermore, we discover that the sum of the expression values for RNA from the genes, ALDH1A1 and ALDH2, has a stronger association with AML patient risk group classification and survival than either one gene alone does. In conclusion, we identify ALDH1A1 and ALDH2 as prospective actionable targets for the treatment of AML in high-risk patients. Substances that inhibit both enzymatic activities constitute potentially effective pharmaceutics.

LNS8801 inhibits Acute Myeloid Leukemia by Inducing the Production of Reactive Oxygen Species and Activating the Endoplasmic Reticulum Stress Pathway

Despite recent therapeutic advances, the 5-year survival rate for adults with acute myeloid leukemia (AML) is poor and standard-of-care chemotherapy is associated with significant toxicity, highlighting the need for new therapeutic approaches. Recent work from our group and others established that the G protein-coupled estrogen receptor (GPER) is tumor suppressive in melanoma and other solid tumors. We performed a preliminary screen of human cancer cell lines from multiple malignancies and found that LNS8801, a synthetic pharmacologic agonist of GPER currently in early phase clinical trials, promoted apoptosis in human AML cells. Using human AML cell lines and primary cells, we show that LNS8801 inhibits human AML in preclinical in vitro models, while not affecting normal mononuclear cells. Although GPER is broadly expressed in normal and malignant myeloid cells, this cancer-specific LNS8801-induced inhibition appeared to be independent of GPER signaling. LNS8801 induced AML cell death primarily through a caspase-dependent apoptosis pathway. This was independent of secreted classical death receptor ligands, and instead required induction of reactive oxygen species (ROS) and activation of endoplasmic reticulum (ER) stress response pathways including IRE1α. These studies demonstrate a novel activity of LNS8801 in AML cells and show that targeting ER stress with LNS8801 may be a useful therapeutic approach for AML.

Significance

Previous work demonstrated that LNS8801 inhibits cancer via GPER activation, especially in solid tumors. Here we show that LNS8801 inhibits AML via GPER-independent mechanisms that include ROS induction and ER activation.

NADPH oxidase mediated oxidative stress signaling in FLT3-ITD acute myeloid leukemia

The internal tandem duplication of the juxtamembrane domain of the FMS-like tyrosine kinase 3 (FLT3-ITD) is the most common genetic change in acute myeloid leukemia (AML), and about 30% of all AMLs harbor a FLT3-ITD mutation. Even though FLT3 inhibitors have displayed encouraging effects in FLT3-ITD-mutated AML, the extent of the clinical response to these compounds is cut short due to the rapid development of drug resistance. Evidence has shown that FLT3-ITD triggered activation of oxidative stress signaling may exert a pivotal role in drug resistance. The downstream pathways of FLT3-ITD, including STAT5, PI3K/AKT, and RAS/MAPK, are considered to be major oxidative stress signaling pathways. These downstream pathways can inhibit apoptosis and promote proliferation and survival by regulating apoptosis-related genes and promoting the generation of reactive oxygen species (ROS) through NADPH oxidase (NOX) or other mechanisms. Appropriate levels of ROS may promote proliferation, but high levels of ROS can lead to oxidative damage to the DNA and increase genomic instability. In addition, post-translational modifications of FLT3-ITD and changes in its subcellular localization can affect downstream signaling which may also be one of the mechanisms leading to drug resistance. In this review, we summarized the research progress on NOX mediated oxidative stress signaling and its relationship with drug resistance in FLT3-ITD AML, and discuss the possible new targets in FLT3-ITD signal blocking to reverse drug resistance in FLT3-ITD-mutated AML.

Inhibition of lung adenocarcinoma by combinations of sulfasalazine (SAS) and disulfiram-copper (DSF-Cu) in cell line models and mice

Sulfasalazine (SAS) is a repurposed antitumor drug which inhibits the proliferation and survival of cancer cells by inhibiting the xCT cellular antioxidant system. Recent clinical studies have shown that, due to poor bioavailability, the antitumor effects of SAS monotherapy are minimal. Therefore, we hypothesized that DSF, another repurposed drug that has demonstrated anticancer effects, or its complex with copper (DSF-copper, DSF-Cu) could potentiate the antilung cancer effects of SAS. Exposure of non-small cell lung cancer cells to therapeutically achievable concentrations of SAS-induced low-to-moderate cytotoxic effects (20-40% reduction in cell viability) and, unexpectedly, induced the antioxidant protein NRF2 and its downstream effectors xCT and ALDH1A1. However, combinations of SAS and DSF-Cu, but not SAS and DSF, induced a significantly higher cytotoxic effect (64-88% reduction in cell viability), apoptosis and generation of mitochondrial reactive oxygen species as compared with SAS or DSF-Cu alone. Moreover, DSF-Cu abrogated SAS-induced NRF2, xCT and ALDH1A1 expression. In a mouse model of lung tumor, SAS + DSF-Cu showed a higher efficacy than the individual drugs in reducing the number and size of tumors as well as the incidence and multiplicity of lung adenocarcinoma. Taken together, our findings indicate that the observed antilung cancer effects of SAS plus DSF-Cu are mediated, at least in part, via impairment of reactive oxygen species defense and -enhancement of oxidative stress and provide evidence for the preventive/therapeutic potential of this combinatorial approach against lung cancer.

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.

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).

Preparation and anticancer actions of CuET-nanoparticles dispersed by bovine serum albumin

Diethyldithiocarbamate-copper complex (CuET) shows promising anticancer effect; nonetheless, preclinical evaluations of CuET are hindered due to poor solubility. We prepared bovine serum albumin (BSA)-dispersed CuET nanoparticles (CuET-NPs) to overcome the shortcoming. Results from a cell-free redox system demonstrated that CuET-NPs reacted with glutathione, leading to form hydroxyl radical. Glutathione-mediated production of hydroxyl radicals may help explain why CuET selectively kills drug-resistant cancer cells with higher levels of glutathione. CuET-NPs dispersed by autoxidation products of green tea epigallocatechin gallate (EGCG) also reacted with glutathione; however, the autoxidation products eradicated hydroxyl radicals; consequently, such CuET-NPs exhibited largely compromised cytotoxicity, suggesting that hydroxyl radical is a crucial mediator of CuET anticancer activity. In cancer cells, BSA-dispersed CuET-NPs exhibited cytotoxic activities equivalent to CuET and induced protein poly-ubiquitination. Moreover, the reported powerful inhibition of CuET on colony formation and migration of cancer cells could be replicated by CuET-NPs. These similarities demonstrate BSA-dispersed CuET-NPs is identical to CuET. Thus, we advanced to pilot toxicological and pharmacological evaluations. CuET-NPs caused hematologic toxicities in mice and induced protein poly-ubiquitination and apoptosis of cancer cells inoculated in mice at a defined pharmacological dose. Given high interest in CuET and its poor solubility, BSA-dispersed CuET-NPs pave the way for preclinical evaluations.

Copper in cancer: From pathogenesis to therapy

One of the basic trace elements for the structure and metabolism of human tissue is copper. However, as a heavy metal, excessive intake or abnormal accumulation of copper in the body can cause inevitable damage to the organism because copper can result in direct injury to various cell components or disruption of the redox balance, eventually leading to cell death. Interestingly, a growing body of research reports that diverse cancers have raised serum and tumor copper levels. Tumor cells depend on more copper for their metabolism than normal cells, and a decrease in copper or copper overload can have a detrimental effect on tumor cells. New modalities for identifying and characterizing copper-dependent signals offer translational opportunities for tumor therapy, but their mechanisms remain unclear. Therefore, this article summarizes what we currently know about the correlation between copper and cancer and describes the characteristics of copper metabolism in tumor cells and the prospective application of copper-derived therapeutics.

Emerging drugs targeting cellular redox homeostasis to eliminate acute myeloid leukemia stem cells

Acute myeloid leukemia (AML) is a very heterogeneous group of disorders with large differences in the percentage of immature blasts that presently are classified according to the specific mutations that trigger malignant proliferation among thousands of mutations reported thus far. It is an aggressive disease for which few targeted therapies are available and still has a high recurrence rate and low overall survival. The main reason for AML relapse is believed to be due to leukemic stem cells (LSCs) that have unlimited self-renewal capacity and long residence in a quiescent state, which promote greater resistance to traditional therapies for this cancer. AML LSCs have low oxidative stress levels, which appear to be caused by a combination of low mitochondrial activity and high activity of ROS-removing pathways. In this sense, oxidative stress has been thought to be an important new potential target for the treatment of AML patients, targeting the eradication of AML LSCs. The aim of this review is to discuss some drugs that induce oxidative stress to direct new goals for future research focusing on redox imbalance as an effective strategy to eliminate AML LSCs.

Hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanocrystals for cancer therapy

Cancer stem cells (CSCs) have been recognized as the culprit for tumor progression, treatment resistance, metastasis, and recurrence while redox homeostasis represents the Achilles' Heel of CSCs. However, few drugs or formulations that are capable of elevating oxidative stress have achieved clinical success for eliminating CSCs. Here, we report hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanoparticles (CuET@HES NPs), which conspicuously suppress CSCs not only in vitro but also in numerous tumor models in vivo. Furthermore, CuET@HES NPs effectively inhibit CSCs in fresh tumor tissues surgically excised from hepatocellular carcinoma patients. Mechanistically, we uncover that hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanocrystals via copper‑oxygen coordination interactions, thereby promoting copper-diethyldithiocarbamate colloidal stability, cellular uptake, intracellular reactive oxygen species production, and CSCs apoptosis. As all components are widely used in clinics, CuET@HES NPs represent promising treatments for CSCs-rich solid malignancies and hold great clinical translational potentials. This study has critical implications for design of CSCs targeting nanomedicines.

Development and validation of a cuproptosis-associated prognostic model for diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a highly heterogeneous disease. Therefore, more reliable biomarkers are required to better predict the prognosis of DLBCL. Cuproptosis is a novel identified form of programmed cell death (PCD) that is different from oxidative stress-related cell death (e.g., apoptosis, ferroptosis, and necroptosis) by Tsvetkov and colleagues in a recent study released in Science. Cuproptosis is copper-dependent PCD that is closely tied to mitochondrial metabolism. However, the prognostic value of cuproptosis-related genes (CRGs) in DLBCL remains to be further elucidated. In the present study, we systematically evaluated the molecular changes of CRGs in DLBCL and found them to be associated with prognosis. Subsequently, based on the expression profiles of CRGs, we characterized the heterogeneity of DLBCL by identifying two distinct subtypes using consensus clustering. Two isoforms exhibited different survival, biological functions, chemotherapeutic drug sensitivity, and immune microenvironment. After identifying differentially expressed genes (DEGs) between CRG clusters, we built a prognostic model with the Least absolute shrinkage and selection operator (LASSO) Cox regression analysis and validated its prognostic value by Cox regression analysis, Kaplan-Meier curves, and receiver operating characteristic (ROC) curves. In addition, the risk score can predict clinical characteristics, levels of immune cell infiltration, and prognosis. Furthermore, a nomogram incorporating clinical features and risk score was generated to optimize risk stratification and quantify risk assessment. Compared to the International Prognostic Index (IPI), the nomogram has demonstrated more accuracy in survival prediction. Furthermore, we validated the prognostic gene expression levels through external experiments. In conclusion, cuproptosis-related gene signature can serve as a potential prognostic predictor in DLBCL patients and may provide new insights into cancer therapeutic targets.

Curcumin combined with arsenic trioxide in the treatment of acute myeloid leukemia: network pharmacology analysis and experimental validation

PURPOSE

This study aimed to evaluate the effects of curcumin by co-administration of arsenic trioxide (As₂O₃) in acute myeloid leukemia (AML) treatment, using network pharmacology and experimental validation.

METHODS

Using Pubchem database, Traditional Chinese Medicine Information Database (TCMID) database, and Swiss target prediction database to predict compound-related targets, AML-associated targets were determined using GeneCards and Online Mendelian Inheritance in Man (OMIM) databases. We identify overlapping common targets by comparing Compounds-related and AML-associated targets and using these targets to perform GO and KEGG functional enrichment analyses. Subsequently, these targets were input into the STRING database, and we used Cytoscape to construct protein-protein interaction (PPI) network. Finally, we used KG1-a cells and the AML mouse model to measure the anti-leukemia effects of curcumin and As₂O₃ and their combination.

RESULTS

Compounds and targets screening hinted that 85 intersection targets were predicted in the curcumin treatment of AML, 75 targets in the As₂O₃ treatment of AML, and 48 targets in the curcumin combined with the As₂O₃ treatment of AML. GO and KEGG analyses indicated that the top 10 enriched biological processes and top 20 pathways implicated in the therapeutic effects of curcumin and As₂O₃ on AML, respectively. In addition, network pharmacology screening revealed STAT3, TP53, EP300, MAPK1, and PIK3CA as the top five genes in PPI network of curcumin treatment of AML and TP53, MAPK3, MAPK1, STAT3, and SRC as the top five genes in PPI network of As₂O₃ treatment of AML. Moreover, the in vitro experiment demonstrated that curcumin combined with As₂O₃ inhibited proliferation and induced apoptosis in KG1-a cells, and this effect is more substantial than curcumin or As₂O₃ alone. Mechanistically, the curcumin combined with As₂O₃ significantly down-regulated the protein expression of JAK2, STAT3, and Bcl-2, and up-regulated the levels of P53, P27, and Bax. In the mouse model, the survival time of mice in each administration group was drawn out to varying degrees, with the most significant prolongation in the curcumin combined with the As₂O₃ group.

CONCLUSION

Our results suggested that curcumin and As₂O₃ combination therapy exerts more significant anti-leukemia effects in the treatment of AML than curcumin or As₂O₃ monotherapy by up-regulating p53 pathway and down-regulating the JAK2/STAT3 pathway.

The treatment of hepatocellular carcinoma with SP94 modified asymmetrical bilayer lipid-encapsulated Cu(DDC)2 nanoparticles facilitating Cu accumulation in the tumor

BACKGROUND

Copper diethyldithiocarbamate (Cu(DDC)₂) has been demonstrated to possess excellent antitumor activity. However, the extremely poor water solubility of Cu(DDC)₂ bring difficulty for its formulation research. In this study, we aim to develop a novel nanocarrier for Cu(DDC)₂ delivery to overcome this obstacle and enhance antitumor activity.

METHODS

The SP94 modified asymmetrical bilayer lipid-encapsulated Cu(DDC)₂ nanoparticles (DCDP) was established by combining the method of inverse microemulsion aggregation and thin-film dispersion. In vitro cellular assays and in vivo tumor-xenograft experiments were conducted to evaluate the tumor chemotherapeutic effect of DCDP. And the vital role of copper ions played in DSF or DDC (DSF/DDC)-based cancer chemotherapy was also explored.

RESULTS

DCDP with an encapsulation efficiency (EE%) of 74.0% were successfully prepared. SP94 modification facilitated cellular intake for DCDP, and promoted apoptosis to repress tumor cell proliferation (IC₅₀, 200 nM). And DCDP effectively inhibited tumor growth with a high tumor inhibition rate of 74.84%. Furthermore, Cu(DDC)₂ was found to facilitate the copper ion accumulation in tumor tissues, which is beneficial to therapy with high potency.

CONCLUSION

DCDP exhibited high-efficient tumor chemotherapeutic efficacy and provided a novel strategy for investigating the anticancer mechanism of Cu(DDC)₂.

Identification and validation of a novel cuproptosis-related gene signature in multiple myeloma

Background: Cuproptosis is a newly identified unique copper-triggered modality of mitochondrial cell death, distinct from known death mechanisms such as necroptosis, pyroptosis, and ferroptosis. Multiple myeloma (MM) is a hematologic neoplasm characterized by the malignant proliferation of plasma cells. In the development of MM, almost all patients undergo a relatively benign course from monoclonal gammopathy of undetermined significance (MGUS) to smoldering myeloma (SMM), which further progresses to active myeloma. However, the prognostic value of cuproptosis in MM remains unknown. Method: In this study, we systematically investigated the genetic variants, expression patterns, and prognostic value of cuproptosis-related genes (CRGs) in MM. CRG scores derived from the prognostic model were used to perform the risk stratification of MM patients. We then explored their differences in clinical characteristics and immune patterns and assessed their value in prognosis prediction and treatment response. Nomograms were also developed to improve predictive accuracy and clinical applicability. Finally, we collected MM cell lines and patient samples to validate marker gene expression by quantitative real-time PCR (qRT-PCR). Results: The evolution from MGUS and SMM to MM was also accompanied by differences in the CRG expression profile. Then, a well-performing cuproptosis-related risk model was developed to predict prognosis in MM and was validated in two external cohorts. The high-risk group exhibited higher clinical risk indicators. Cox regression analyses showed that the model was an independent prognostic predictor in MM. Patients in the high-risk group had significantly lower survival rates than those in the low-risk group (p < 0.001). Meanwhile, CRG scores were significantly correlated with immune infiltration, stemness index and immunotherapy sensitivity. We further revealed the close association between CRG scores and mitochondrial metabolism. Subsequently, the prediction nomogram showed good predictive power and calibration. Finally, the prognostic CRGs were further validated by qRT-PCR in vitro. Conclusion: CRGs were closely related to the immune pattern and self-renewal biology of cancer cells in MM. This prognostic model provided a new perspective for the risk stratification and treatment response prediction of MM patients.

Molecular typing and prognostic model of lung adenocarcinoma based on cuprotosis-related lncRNAs

Background

Previous research has shown the heterogeneity of lung adenocarcinoma (LUAD) accounts for the different effects and prognoses of the same treatment. Cuprotosis is a newly discovered form of programmed cell death involved in the development of tumors. Therefore, it is important to study the long non-coding RNAs (lncRNAs) that regulate cuprotosis to identify molecular subtypes and predict survival of LUAD.

Methods

The expression profile, clinical, and mutation data of LUAD were downloaded from The Cancer Genome Atlas (TCGA), and the "ConsensusClusterPlus" package was used to cluster LUADs based on cuprotosis-related lncRNAs (CR-lncRNAs). The least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression were used to construct a prognostic model. CIBERSORT and single-sample gene set enrichment analysis (ssGSEA) were used for assessing immune cells infiltration and immune function. The tumor microenvironment (TME) score was calculated by ESTIMATE, and the tumor mutational burden (TMB) and Tumor Immune Dysfunction and Exclusion (TIDE) were used to evaluate the efficacy of immunotherapy.

Results

Firstly, 501 CR-lncRNAs were identified based on the co-expression relationship of 19 cuprotosis genes. And univariate Cox further obtained 34 prognosis-related CR-lncRNAs. The unsupervised consensus clustering divided LUAD samples into cluster A and cluster B, and showed cluster A had better prognosis, more immune cells infiltration, stronger immune function, and a higher TME score. Subsequently, we used Lasso Cox regression to construct a prognostic model, and univariate and multivariate Cox analyses showed the risk score could be an independent prognostic indicator. Immune cells infiltration, immune function, and TME score were increased markedly in the low-risk group, while TMB and TIDE suggested the efficacy of immunotherapy might be increased in high-risk group.

Conclusions

Our research identified two new molecular subtypes and constructed a novel prognostic model of LUAD which could provide new direction for its diagnosis, treatment, and prognosis.

Redox balance and autophagy regulation in cancer progression and their therapeutic perspective

Cellular ROS production participates in various cellular functions but its accumulation decides the cell fate. Malignant cells have higher levels of ROS and active antioxidant machinery, a characteristic hallmark of cancer with an outcome of activation of stress-induced pathways like autophagy. Autophagy is an intracellular catabolic process that produces alternative raw materials to meet the energy demand of cells and is influenced by the cellular redox state thus playing a definite role in cancer cell fate. Since damaged mitochondria are the main source of ROS in the cell, however, cancer cells remove them by upregulating the process of mitophagy which is known to play a decisive role in tumorigenesis and tumor progression. Chemotherapy exploits cell machinery which results in the accumulation of toxic levels of ROS in cells resulting in cell death by activating either of the pathways like apoptosis, necrosis, ferroptosis or autophagy in them. So understanding these redox and autophagy regulations offers a promising method to design and develop new cancer therapies that can be very effective and durable for years. This review will give a summary of the current therapeutic molecules targeting redox regulation and autophagy for the treatment of cancer. Further, it will highlight various challenges in developing anticancer agents due to autophagy and ROS regulation in the cell and insights into the development of future therapies.

Preclinical Evaluation of the Multiple Tyrosine Kinases Inhibitor Anlotinib in Leukemia Stem Cells

Leukemia stem cells (LSCs) constitute the critical barrier to the cure of acute myeloid leukemia (AML) due to their chemoresistance and immune evasion property. Herein, the role of anlotinib, a multiple tyrosine kinase inhibitor, in killing LSCs and regulating chemoresistance and immune evasion was explored. Anlotinib treatment induced apoptosis of LSC-like cells as well as primary AML LSCs, while sparing the normal mononuclear cells in vitro. Moreover, anlotinib could impair the regeneration capacity of LSCs in the patient-derived leukemia xenograft mouse model. Mechanistically, anlotinib inhibited phosphorylation of c-kit, JAK2/STAT3, and STAT5, and downregulated STAT3 and STAT5 expression. In addition, anlotinib downregulated the anti-apoptotic proteins Bcl-2 and Bcl-xL, and upregulated Bax, thereby enhancing the sensitivity of LSCs to idarubicin in vitro. Intriguingly, anlotinib could also partially rescue the interferon-g production of T cells cocultured with LSCs by downregulating PD-L1 expression. In conclusion, anlotinib showed anti-LSC activity and the potential to enhance the sensitivity to idarubicin and inhibit the immunosuppressive feature of LSCs via JAK2/STAT signaling pathway downregulation in the preclinical study. Our results provided a rational basis for combinatory strategies involving anlotinib and chemotherapy or immunotherapy.

A novel cuproptosis-related LncRNA signature: Prognostic and therapeutic value for acute myeloid leukemia

Background

Cuproptosis is a type of programmed cell death that is involved in multiple physiological and pathological processes, including cancer. We constructed a prognostic cuproptosis-related long non-coding RNA (lncRNA) signature for acute myeloid leukemia (AML).

Methods

RNA-seq and clinical data for AML patients were acquired from The Cancer Genome Atlas (TCGA) database. The cuproptosis-related prognostic lncRNAs were identified by co-expression and univariate Cox regression analysis. The least absolute shrinkage and selection operator (LASSO) was performed to construct a cuproptosis-related lncRNA signature, after which the AML patients were classified into two risk groups based on the risk model. Kaplan-Meier, ROC, univariate and multivariate Cox regression, nomogram, and calibration curves analyses were used to evaluate the prognostic value of the model. Then, expression levels of the lncRNAs in the signature were investigated in AML samples by quantitative polymerase chain reaction (qPCR). KEGG functional analysis, single-sample GSEA (ssGSEA), and the ESTIMATE algorithm were used to analyze the mechanisms and immune status between the different risk groups. The sensitivities for potential therapeutic drugs for AML were also investigated.

Results

Five hundred and three lncRNAs related to 19 CRGs in AML samples from the TCGA database were obtained, and 21 differentially expressed lncRNAs were identified based on the 2-year overall survival (OS) outcomes of AML patients. A 4-cuproptosis-related lncRNA signature for survival was constructed by LASSO Cox regression. High-risk AML patients exhibited worse outcomes. Univariate and multivariate Cox regression analyses demonstrated the independent prognostic value of the model. ROC, nomogram, and calibration curves analyses revealed the predictive power of the signature. KEGG pathway and ssGSEA analyses showed that the high-risk group had higher immune activities. Lastly, AML patients from different risk groups showed differential responses to various agents.

Conclusion

A cuproptosis-related lncRNA signature was established to predict the prognosis and inform on potential therapeutic strategies for AML patients.

The anti-alcoholism drug disulfiram effectively ameliorates ulcerative colitis through suppressing oxidative stresses-associated pyroptotic cell death and cellular inflammation in colonic cells

BACKGROUND

Oxidative stress, cell pyroptosis and inflammation are considered as important pathogenic factors for ulcerative colitis (UC) development, and the traditional anti-alcoholism drug disulfiram (DSF) has recently been reported to exert its regulating effects on all the above cellular functions, which makes DSF as ideal therapeutic agent for UC treatment, but this issue has not been fully studied.

METHODS

Dextran sulfate sodium (DSS)-induced animal models in C57BL/6J mice and lipopolysaccharide (LPS)-induced cellular models in colonic cell lines (HT-29 and Caco-2) for UC were respectively established. Cytokine secretion was determined by ELISA. Cell viability and proliferation were evaluated by MTT assay and EdU assay. Real-Time qPCR, Western Blot, immunofluorescent staining assay and immunohistochemistry (IHC) were employed to evaluate gene expressions. The correlations of the genes in the clinical tissues were analyzed by using the Pearson Correlation analysis.

RESULTS

DSF restrained oxidative stress, pyroptotic cell death and cellular inflammation in UC models in vitro and in vivo, and elimination of Reactive Oxygen Species (ROS) by N-acetyl-l-cysteine (NAC) rescued cell viability in LPS-treated colonic cells (HT-29 and Caco-2). Further experiments suggested that a glycogen synthase kinase-3β (GSK-3β)/Nrf2/NLRP3 signaling cascade played critical role in this process. Mechanistically, DSF downregulated GSK-3β and NLRP3, whereas upregulated Nrf2 in LPS-treated colonic cells. Also, the regulating effects of DSF on Nrf2 and NLRP3 were abrogated by upregulating GSK-3β. Moreover, upregulation of GSK-3β abolished the protective effects of DSF on LPS-treated colonic cells.

CONCLUSIONS

Taken together, data of this study indicated that DSF restrained oxidative damages-related pyroptotic cell death and inflammation via regulating the GSK-3β/Nrf2/NLRP3 pathway, leading to the suppression of LPS-induced UC development.

The molecular biology and therapeutic potential of Nrf2 in leukemia

NF-E2-related factor 2 (Nrf2) transcription factor has contradictory roles in cancer, which can act as a tumor suppressor or a proto-oncogene in different cell conditions (depending on the cell type and the conditions of the cell environment). Nrf2 pathway regulates several cellular processes, including signaling, energy metabolism, autophagy, inflammation, redox homeostasis, and antioxidant regulation. As a result, it plays a crucial role in cell survival. Conversely, Nrf2 protects cancerous cells from apoptosis and increases proliferation, angiogenesis, and metastasis. It promotes resistance to chemotherapy and radiotherapy in various solid tumors and hematological malignancies, so we want to elucidate the role of Nrf2 in cancer and the positive point of its targeting. Also, in the past few years, many studies have shown that Nrf2 protects cancer cells, especially leukemic cells, from the effects of chemotherapeutic drugs. The present paper summarizes these studies to scrutinize whether targeting Nrf2 combined with chemotherapy would be a therapeutic approach for leukemia treatment. Also, we discussed how Nrf2 and NF-κB work together to control the cellular redox pathway. The role of these two factors in inflammation (antagonistic) and leukemia (synergistic) is also summarized.

DSF/Cu induces antitumor effect against diffuse large B-cell lymphoma through suppressing NF-κB/BCL6 pathways

Background

The B-cell lymphoma 6 (BCL6) oncogene is required for the survival of diffuse large B-cell lymphoma (DLBCL), which is incurable using conventional chemotherapy. Thus, it is imperative to improve the survival of patients with DLBCL. Disulfide (DSF) has been shown to have anticancer effects, but its effect on DLBCL remains unclear.

Methods

Four DLBCL cell lines (OCI-LY1, OCI-LY7, OCI-LY10 and U2932) and primary DLBCL cells from eight newly diagnosed DLBCL patients were pretreated with DSF alone or in combination with Cu. Cell morphology was observed under microscope. Flow cytometry was performed to evaluate the cell apoptosis, cell cycle, the mitochondrial membrane potential and the intracellular accumulation of reactive oxygen species (ROS). The protein expression was respectively measured by flow cytometry and western blotting.

Results

DSF or DSF/Cu exhibited a marked inhibitory effect on the growth of DLBCL cells, accompanied by cell cycle arrest at the G0/G1 phase. Meanwhile, DSF or DSF/Cu significantly induced DLBCL cells apoptosis. Further study revealed that DSF or DSF/Cu promoted apoptosis by inhibiting NF-κB signaling pathway. Interestingly, DSF/Cu significantly reduced BCL6 and AIP levels. In addition, DSF significantly up-regulate p53 protein in OCI-LY7 and OCI-LY10 while down-regulate p53 protein in OCI-LY1 and U2932.

Conclusion

These results provided evidence for the anti-lymphoma effects of DSF on DLBCL and suggested that DSF has therapeutic potential to DLBCL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02661-4.

Nrf2 Overexpression Decreases Vincristine Chemotherapy Sensitivity Through the PI3K-AKT Pathway in Adult B-Cell Acute Lymphoblastic Leukemia

Uncontrolled proliferation is an important cancer cell biomarker, which plays a critical role in carcinogenesis, progression and development of resistance to chemotherapy. An improved understanding of novel genes modulating cancer cell proliferation and mechanism will help develop new therapeutic strategies. The nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor, decreases apoptosis when its expression is upregulated. However, the relationship between Nrf2 and Vincristine (VCR) chemotherapy resistance in B-cell acute lymphoblastic leukemia (B-ALL) is not yet established. Our results showed that Nrf2 levels could sufficiently modulate the sensitivity of B-ALL cells to VCRby regulating an apoptotic protein, i.e., the Bcl-2 agonist of cell death (BAD). Chemotherapeutic agents used for the treatment of B-ALL induced Nrf2 overactivation and PI3K-AKT pathway activation in the cells, independent of the resistance to chemotherapy; thus, a potential resistance loop during treatment for B-ALL with a drug combination is established. Therefore, B-ALL patients with a high expression of Nrf2 might mean induction chemotherapy with VCR effective little.

Disulfiram/Copper induces antitumor activity against gastric cancer via the ROS/MAPK and NPL4 pathways

Disulfiram (DSF) is an anti-alcoholism medication with superior antitumor activity and clinical safety; its antitumor mechanisms in gastric cancer (GC) have not been fully explored. In the present work, low nontoxic concentrations of copper (Cu) ions substantially enhanced DSF’s antitumor activity, inhibiting the proliferation and growth of GC cell lines. DSF/Cu elevated the generation of reactive oxygen species (ROS), and apoptosis was induced in an ROS-dependent manner. This process might involve primary inhibition GC by DSF/Cu through induction of apoptosis via the ROS/mitogen-activated protein kinase pathway. Disordering transportation of ubiquitinated protein may also fuel the process. In summary, we found that DSF exerts antitumor effects on GC. DSF/Cu should be considered as adjunctive therapy for GC.

Selective Targeting of Cancer Cells by Copper Ionophores: An Overview

Conventional cancer therapies suffer from severe off-target effects because most of them target critical facets of cells that are generally shared by all rapidly proliferating cells. The development of new therapeutic agents should aim to increase selectivity and therefore reduce side effects. In addition, these agents should overcome cancer cell resistance and target cancer stem cells. Some copper ionophores have shown promise in this direction thanks to an intrinsic selectivity in preferentially inducing cuproptosis of cancer cells compared to normal cells. Here, Cu ionophores are discussed with a focus on selectivity towards cancer cells and on the mechanisms responsible for this selectivity. The proposed strategies, to further improve the targeting of cancer cells by copper ionophores, are also reported.

Disulfiram/copper induces antitumor activity against gastric cancer cells in vitro and in vivo by inhibiting S6K1 and c-Myc

PURPOSE

Disulfiram (DSF) is an approved drug for the treatment of alcohol dependence. Accumulating evidence indicates that DSF, alone or in combination with copper (Cu), possesses strong antitumor activity in various malignancies. This study investigated the effects of DSF on gastric cancer (GC) and the potential mechanisms involved.

METHODS

GC cell proliferation and apoptosis upon treatment with DSF with or without copper were analyzed using CCK-8 assay, colony formation assay, and flow cytometry. Glucose metabolism was investigated using glucose consumption and lactate production assays. The expression of caspase-3, Bcl-2, LC-3, P62, S6K1, c-Myc, GLUT1, PKM2, and LDHA was analyzed using western blot assay. In vivo nude mice studies were performed to verify the findings from in vitro analyses.

RESULTS

Our study showed that DSF was highly toxic to GC cells in a Cu-dependent manner. Nontoxic concentrations of Cu enhanced the inhibitory effects of DSF on cell viability and colony formation. DSF also induced apoptotic and autophagic cell death in the presence of Cu. In addition, DSF/Cu inhibited glycolysis and xenograft growth of GC cells by suppressing the expression of S6K1, c-Myc, and their downstream molecules, including GLUT1, PKM2, and LDHA.

CONCLUSION

Our study demonstrated that DSF/Cu exerted antitumor activity against GC cells both in vitro and in vivo. DSF/Cu may represent a promising therapeutic strategy for the treatment of GC.

The ionophore thiomaltol induces rapid lysosomal accumulation of copper and apoptosis in melanoma

In this report, we investigate the toxicity of the ionophore thiomaltol (Htma) and Cu salts to melanoma. Divalent metal complexes of thiomaltol display toxicity against A375 melanoma cell culture resulting in a distinct apoptotic response at submicromolar concentrations, with toxicity of Cu(tma)2 > Zn(tma)2 >> Ni(tma)2. In metal-chelated media, Htma treatment shows little toxicity, but the combination with supplemental CuCl2, termed Cu/Htma treatment, results in toxicity that increases with suprastoichiometric concentrations of CuCl2 and correlates with the accumulation of intracellular copper. Electron microscopy and confocal laser scanning microscopy of Cu/Htma treated cells shows a rapid accumulation of copper within lysosomes over the course of hours, concurrent with the onset of apoptosis. A buildup of ubiquitinated proteins due to proteasome inhibition is seen on the same timescale and correlates with increases of copper without additional Htma.

Nrf2 overexpression increases the resistance of acute myeloid leukemia to cytarabine by inhibiting replication factor C4

Drug resistance is a key factor in the treatment failure of acute myeloid leukemia (AML). Nuclear factor E2-related factor 2 (Nrf2) plays a crucial role in tumor chemotherapy resistance. However, the potential mechanism of Nrf2 regulating DNA mismatch repair (MMR) pathway to mediate gene-instability drug resistance in AML is still unclear. Here, it was found that Nrf2 expression was closely related to the disease progression of AML as well as highly expressed in AML patients with poor prognostic gene mutations. Meanwhile, it was also found that the expression of Nrf2 was significantly negatively correlated with DNA MMR gene replication factor C4 (RFC4) in AML. CHIP analysis combined with luciferase reporter gene results further showed that Nrf2 may inhibit the expression of RFC4 by its interaction with the RFC4 promoter. In vitro and vivo experiments showed that the overexpression of Nrf2 decreased the killing effect of chemotherapy drug cytarabine (Ara-C) on leukemia cells and inhibited the expression of RFC4. Mechanistically, The result that Nrf2-RFC4 axis mediated AML genetic instability drug resistance might be received by activating the JNK/NF-κB signaling pathway. Taken together, these findings may provide a new idea for improving AML drug resistance.

Disulfiram attenuates MCMV-Induced pneumonia by inhibition of NF-κB/NLRP3 signaling pathway in immunocompromised mice

Cytomegalovirus (CMV) pneumonia in immunocompromised individuals is associated with damaging hyperinflammation and leads to high morbidity and mortality. It is urgently needed to develop new strategies to treat CMV-induced pneumonia. As disulfiram (DSF) reportedly inhibits inflammatory responses in different disease models, its therapeutic effects in CMV-induced pneumonia are proposed. In this study, we demonstrated that DSF effectively attenuated pulmonary injury and improved survival in murine CMV (MCMV) pneumonia model. DSF treatment inhibited lung inflammatory responses, e.g. reducing pro-inflammatory cytokines, upregulating anti-inflammatory cytokine, and lowering the accumulation of leukocytes in the lung. Similar to the in vivo results, DSF attenuated inflammatory responses and modulated NF-κB/NLRP3 inflammasome activation in MCMV-infected BMDMs. Furthermore, DSF reduced pulmonary fibrosis and viral loads in MCMV pneumonia mice and BMDMs. The mechanism of anti-inflammatory effects of DSF may due to its regulating NF-κB signaling and NLRP3 inflammasome activation. Collectively, our results suggest that DSF-mediated anti-hyperinflammatory effects have potentials for therapy of human CMV pneumonia.

Combination of the 6-thioguanine and disulfiram/Cu synergistically inhibits proliferation of triple-negative breast cancer cells by enhancing DNA damage and disrupting DNA damage checkpoint

Because of the lack of specific molecular targeted therapies, triple-negative breast cancer (TNBC) has high tumour recurrence and metastasis rates. It is urgent to develop novel chemotherapeutic strategies to improve patient survival. DNA damaging agents have been shown to sensitize cancer to genotoxic chemotherapies. We first found that 6-thioguanine (6-TG) can activate the NF-кB signalling pathway. Our results showed that NF-кB signalling was reduced when cells were treated with 6-TG/disulfiram (DSF)/Cu. DSF/Cu enhanced the 6-TG-mediated inhibition of proliferation. 6-TG/DSF/Cu inhibited cell cycle progression, causing cell cycle arrest in the S phase and G2/M phase. Moreover, the combined effect of 6-TG and DSF/Cu induced apoptosis, and either agent alone was able to induce apoptosis. The accumulation of γH2A indicated that DSF/Cu increased the DNA damage induced by 6-TG. Combined treatment with 6-TG and DSF/Cu synergistically reduced the levels of both phosphorylated and total ataxia-telangiectasia-mutated-and-Rad3-related kinase (ATR), suggesting that DSF/Cu promoted 6-TG-induced DNA damage by suppressing ATR protein kinases, therefore enhancing cell apoptosis. In conclusion, we demonstrate that the combination of 6-TG and DSF/Cu exerted a significant synergistic antitumour effect on human TNBC in vitro and in vivo by enhancing DNA damage and disrupting DNA damage checkpoints. We propose that this combination therapy could be a novel strategy for the treatment of TNBC.

Recent Advances in Repurposing Disulfiram and Disulfiram Derivatives as Copper-Dependent Anticancer Agents

Copper (Cu) plays a pivotal role in cancer progression by acting as a co-factor that regulates the activity of many enzymes and structural proteins in cancer cells. Therefore, Cu-based complexes have been investigated as novel anticancer metallodrugs and are considered as a complementary strategy for currently used platinum agents with undesirable general toxicity. Due to the high failure rate and increased cost of new drugs, there is a global drive towards the repositioning of known drugs for cancer treatment in recent years. Disulfiram (DSF) is a first-line antialcoholism drug used in clinics for more than 65 yr. In combination with Cu, it has shown great potential as an anticancer drug by targeting a wide range of cancers. The reaction between DSF and Cu ions forms a copper diethyldithiocarbamate complex (Cu(DDC)₂ also known as CuET) which is the active, potent anticancer ingredient through inhibition of NF-κB and ubiquitin-proteasome system as well as alteration of the intracellular reactive oxygen species (ROS). Importantly, DSF/Cu inhibits several molecular targets related to drug resistance, stemness, angiogenesis and metastasis and is thus considered as a novel strategy for overcoming tumour recurrence and relapse in patients. Despite its excellent anticancer efficacy, DSF has proven unsuccessful in several cancer clinical trials. This is likely due to the poor stability, rapid metabolism and/or short plasma half-life of the currently used oral version of DSF and the inability to form Cu(DDC)₂ at relevant concentrations in tumour tissues. Here, we summarize the scientific rationale, molecular targets, and mechanisms of action of DSF/Cu in cancer cells and the outcomes of oral DSF ± Cu in cancer clinical trials. We will focus on the novel insights on harnessing the immune system and hypoxic microenvironment using DSF/Cu complex and discuss the emerging delivery strategies that can overcome the shortcomings of DSF-based anticancer therapies and provide opportunities for translation of DSF/Cu or its Cu(DDC)₂ complex into cancer therapeutics.

Disulfiram and metformin combination anticancer effect reversible partly by antioxidant nitroglycerin and completely by NF-κB activator mebendazole in hamster fibrosarcoma

We investigated the anticancer effect of disulfiram and metformin combination on fibrosarcoma in hamsters. Hamsters of both sexes (~ 70 g) were randomly allocated to control and experimental groups (8 animals per group). In all 10 groups, 2 × 10⁶ BHK-21/C13 cells in 1 ml were injected subcutaneously into the animals' backs. Peroral treatments were carried out with disulfiram 50 mg/kg daily, or with metformin 500 mg/kg daily, or with their combination. Validation and rescue grups were treated by double doses of the single therapy and by the combination with addition of rescue daily doses of ROS inhibitor nitroglycerin 25 mg/kg or NF-κB stimulator mebendazole 460 mg/kg, via a gastric probe after tumor inoculation. After 19 days all animals were sacrificed. Blood samples were collected for hematological and biochemical analyses, the tumors were excised and weighed, and their diameters and volumes were measured. The tumor samples were pathohistologically and immunohistochemically assessed (Ki-67, PCNA, CD34, CD31, COX4, Cytochrome C, GLUT1, iNOS), and the main organs were toxicologically tested. The combination of disulfiram and metformin significantly inhibited fibrosarcoma growth in hamsters without toxicity, compared to monotherapy or control. The single treatments did not show significant antisarcoma effect. Co-treatment with nitroglycerin partly rescued tumor progression, probably by ROS inhibition, while mebendazole completely blocked anticancer activity of the disulfiram and metformin combination, most likely by NF-κB stimulation. Combination of disulfiram with metformin may be used as an effective and safe candidate for novel nontoxic adjuvant and relapse prevention anticancer therapy.

Disulfiram/copper shows potent cytotoxic effects on myelodysplastic syndromes via inducing Bip-mediated apoptosis and suppressing autophagy

Patients with myelodysplastic syndromes (MDS) who resist or fail to respond to hypomethylating agents (HMAs) show very poor outcomes and have no effective treatment strategies. Therefore, new therapeutic approaches are urgently needed for MDS patients harboring adverse prognostic factors. Repurposing disulfiram (DSF), an alcohol-abuse drug, with or without Copper (Cu) has attracted considerable attentions as a candidate anti-tumor therapy in diverse malignancies. However, the effect of DSF in the presence or absence of Cu on MDS has not been reported yet. In this study, we found that monotherapy with DSF showed mild cytotoxic effects on MDS preclinical models. However, the anti-tumor activity of DSF was significantly enhanced in the presence of Cu in MDS in vitro and in vivo with minimal safety profiles. DSF/Cu combination blocked MDS cell cycle progression at the G0/G1 phase, accompanied by reduction of the S phase. Accordingly, co-treatment with DSF and Cu downregulated the expression of Cyclin D1 and Cyclin A2, whereas this combination upregulated the level of P21 and P27. Mechanistically, the anti-MDS effectiveness of DSF/Cu was potentially associated with activation of the ER stress-related Bip pathway and inactivation of the Akt pathway. In addition, inhibition of autophagy process also contributed to the cytotoxicity of DSF/Cu in MDS cells. In conclusion, these findings provide impressive evidence that the DSF/Cu complex shows potent anti-tumor efficacies on MDS preclinical models, representing a potential alternative therapy for MDS patients and warranting further investigation in clinical contexts.