Disulfiram and its novel derivative sensitize prostate cancer cells to the growth regulatory mechanisms of the cell by re-expressing the epigenetically repressed tumor suppressor-estrogen receptor β

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.

Exploring Disulfiram's Anticancer Potential: PLGA Nano-Carriers for Prolonged Drug Delivery and Potential Improved Therapeutic Efficacy

Disulfiram (DS) has been shown to have potent anti-cancer activity; however, it is also characterised by its low water solubility and rapid metabolism in vivo. Biodegradable polylactic-co-glycolic acid (PLGA) polymers have been frequently employed in the manufacturing of PLGA nano-carrier drug delivery systems. Thus, to develop DS-loaded PLGA nanoparticles (NPs) capable of overcoming DS's limitations, two methodologies were used to formulate the NPs: direct nanoprecipitation (DNP) and single emulsion/solvent evaporation (SE), followed by particle size reduction. The DNP method was demonstrated to produce NPs of superior characteristics in terms of size (151.3 nm), PDI (0.083), charge (-37.9 mV), and loading efficiency (65.3%). Consequently, NPs consisting of PLGA and encapsulated DS coated with mPEG2k-PLGA at adjustable ratios were prepared using the DNP method. Formulations were then characterised, and their stability in horse serum was assessed. Results revealed the PEGylated DS-loaded PLGA nano-carriers to be more efficient; hence, in-vitro studies testing these formulations were subsequently performed using two distinct breast cancer cell lines, showing great potential to significantly enhance cancer therapy.

ATPase Copper Transporting Beta (ATP7B) Is a Novel Target for Improving the Therapeutic Efficacy of Docetaxel by Disulfiram/Copper in Human Prostate Cancer

Docetaxel has been the standard first-line chemotherapy for lethal metastatic prostate cancer (mPCa) since 2004, but resistance to docetaxel treatment is common. The molecular mechanisms of docetaxel resistance remain largely unknown and could be amenable to interventions that mitigate resistance. We have recently discovered that several docetaxel-resistant mPCa cell lines exhibit lower uptake of cellular copper and uniquely express higher levels of a copper exporter protein ATP7B. Knockdown of ATP7B by silencing RNAs (siRNA) sensitized docetaxel-resistant mPCa cells to the growth-inhibitory and apoptotic effects of docetaxel. Importantly, deletions of ATP7B in human mPCa tissues predict significantly better survival of patients after their first chemotherapy than those with wild-type ATP7B (P = 0.0006). In addition, disulfiram (DSF), an FDA-approved drug for the treatment of alcohol dependence, in combination with copper, significantly enhanced the in vivo antitumor effects of docetaxel in a docetaxel-resistant xenograft tumor model. Our analyses also revealed that DSF and copper engaged with ATP7B to decrease protein levels of COMM domain-containing protein 1 (COMMD1), S-phase kinase-associated protein 2 (Skp2), and clusterin and markedly increase protein expression of cyclin-dependent kinase inhibitor 1 (p21/WAF1). Taken together, our results indicate a copper-dependent nutrient vulnerability through ATP7B exporter in docetaxel-resistant prostate cancer for improving the therapeutic efficacy of docetaxel.

Antifungal activity of the repurposed drug disulfiram against Cryptococcus neoformans

Fungal infections have become clinically challenging owing to the emergence of drug resistance in invasive fungi and the rapid increase in the number of novel pathogens. The development of drug resistance further restricts the use of antifungal agents. Therefore, there is an urgent need to identify alternative treatments for Cryptococcus neoformans (C. neoformans). Disulfiram (DSF) has a good human safety profile and promising applications as an antiviral, antifungal, antiparasitic, and anticancer agent. However, the effect of DSF on Cryptococcus is yet to be thoroughly investigated. This study investigated the antifungal effects and the mechanism of action of DSF against C. neoformans to provide a new theoretical foundation for the treatment of Cryptococcal infections. In vitro studies demonstrated that DSF inhibited Cryptococcus growth at minimum inhibitory concentrations (MICs) ranging from 1.0 to 8.0 μg/mL. Combined antifungal effects have been observed for DSF with 5-fluorocytosine, amphotericin B, terbinafine, or ketoconazole. DSF exerts significant protective effects and synergistic effects combined with 5-FU for Galleria mellonella infected with C. neoformans. Mechanistic investigations showed that DSF dose-dependently inhibited melanin, urease, acetaldehyde dehydrogenase, capsule and biofilm viability of C. neoformans. Further studies indicated that DSF affected C. neoformans by interfering with multiple biological pathways, including replication, metabolism, membrane transport, and biological enzyme activity. Potentially essential targets of these pathways include acetaldehyde dehydrogenase, catalase, ATP-binding cassette transporter (ABC transporter), and iron-sulfur cluster transporter. These findings provide novel insights into the application of DSF and contribute to the understanding of its mechanisms of action in C. neoformans.

Disulfiram ameliorates bleomycin induced pulmonary inflammation and fibrosis in rats

Bleomycin (BL) is a widely used anticancer drug that can cause pulmonary fibrosis due to increased fibroblast proliferation and increased secretion of extracellular matrix. RASSF1A is a tumor suppressor gene that is down-regulated by DNA methylation during fibrosis. Disulfiram (DSF), a noncytosine DNA methyltransferase inhibitor, can revert epigenetic biomarkers and re-express silenced genes. We investigated anti-inflammatory and anti-fibrotic effects of DSF on regulation of epigenetic molecules and histopathology in a rat model of BL induced pulmonary fibrosis. We used six groups of rats: sesame oil (SO) control (Co) group, BL group, BL + SO group and three BL + DSF groups administered 1 mg/kg DSF (BL + DSF), 10 mg/kg DSF (BL + DSF10) or 100 mg/kg DSF (BL + DSF100), respectively. BL was administered intratracheally to induce pulmonary fibrosis. DSF and SO were injected intraperitoneally (i.p.) 2 days before BL administration; these injections were continued for 3 weeks. At the end of the study, lung tissues were removed for molecular and histopathologic studies. Administration of 10 or 100 mg/kg DSF after BL induced pulmonary inflammation and fibrosis, and up-regulated RASSF1A and down-regulated TNF-α and IL-1 β compared to the BL and BL + SO groups. A RASSF1A unmethylated band was observed using the methylation-specific PCR technique in rats that had been administered 10 and 100 mg/kg DSF, which indicated partial DNA demethylation. Histopathologic evaluation revealed that fibrosis and all inflammatory scores were decreased significantly in the BL + DSF10 and BL + DSF100 groups compared to the BL group. Our findings indicate that DSF modified DNA methylation by up-regulating RASSF1A, which reduced inflammation and fibrosis in BL induced pulmonary inflammation and fibrosis.

Disulfiram suppresses epithelial-mesenchymal transition (EMT), migration and invasion in cervical cancer through the HSP90A/NDRG1 pathway

Disulfiram (DSF) has proven to be a promising anti-tumor drug in preclinical studies. However, its anti-cancer mechanism has not yet been elucidated. As an activator in tumor metastasis, N-myc downstream regulated gene-1 (NDRG1) is involved in multiple oncogenic signaling pathways and is upregulated by cell differentiation signals in various cancer cell lines. DSF treatment results in a significant reduction in NDRG1, while down-regulated NDRG1 has a pronounced effect on invading cancer cells, as shown in our previous work. Here, in vitro and in vivo experiments confirm that DSF contributes to regulating tumor growth, EMT, and the migration and invasion of cervical cancer. Furthermore, our results show DSF binds to the ATP-binding pocket in the N-terminal domain of HSP90A, thereby affecting the expression of its client protein NDRG1. To our knowledge, this is the first report of DSF binding to HSP90A. In conclusion, this study sheds light on the molecular mechanism by which DSF inhibits tumor growth and metastasis through the HSP90A/NDRG1/β-catenin pathway in cervical cancer cells. These findings provide novel insights into the mechanism underlying DSF function in cancer cells.

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).

Inhibition of the chemokine signal regulator FROUNT by disulfiram ameliorates crescentic glomerulonephritis

Activated monocytes/macrophages promote glomerular injury, including crescent formation, in anti-glomerular basement membrane (GBM) glomerulonephritis. Disulfiram, an alcohol-aversion drug, inhibits monocyte/macrophage migration by inhibiting FROUNT, a cytosolic protein that enhances chemokine receptor signaling. Our study found that disulfiram at a human equivalent dose successfully blocked albuminuria and crescent formation with podocyte loss, and later stage kidney fibrotic lesions, in a rat model of anti-GBM glomerulonephritis. A disulfiram derivative, DSF-41, with more potent FROUNT inhibition activity, inhibited glomerulonephritis at a lower dose than disulfiram. Disulfiram markedly reduced the number of monocytes or macrophages at the early stage of glomerulonephritis and that of CD3⁺ and CD8⁺ lymphocytes at the established stage. Impaired pseudopodia formation was observed in the glomerular monocytes/macrophages of the disulfiram group; consistent with the in vitro observation that disulfiram blocked chemokine-dependent pseudopodia formation and chemotaxis of bone marrow-derived monocytes/macrophages. Furthermore, disulfiram suppressed macrophage activation as revealed by reduced expression of inflammatory cytokines and chemokines (TNF-α, CCL2, and CXCL9) and reduced CD86 and MHC class II expressions in monocytes/macrophages during glomerulonephritis. The dramatic reduction in monocyte/macrophage number might have resulted from disulfiram suppression of both the chemotactic response of monocytes/macrophages and their subsequent activation to produce cytokines and chemokines, which further recruit monocytes. Additionally, FROUNT was expressed in CD68⁺ monocytes/macrophages infiltrating the crescentic glomeruli in human anti-GBM glomerulonephritis. Thus, disulfiram can be a highly effective and safe drug for the treatment of glomerulonephritis by blocking the chemotactic responses of monocytes/macrophages and their activation status in the glomerulus.

Anticancer effects of disulfiram: a systematic review of in vitro, animal, and human studies

BACKGROUND AND OBJECTIVES

Cancer morbidity and mortality rates remain high, and thus, at present, considerable efforts are focused on finding drugs with higher sensitivity against tumor cells and fewer side effects. Disulfiram (DSF), as an anti-alcoholic drug, kills the cancer cells by inducing apoptosis. Several preclinical and clinical studies have examined the potential of repurposing DSF as an anticancer treatment. This systematic review aimed to assess evidence regarding the antineoplastic activity of DSF in in vitro and in vivo models, as well as in humans.

METHODS

Two authors independently conducted this systematic review of English and Chinese articles from the PubMed, Embase, and the Cochrane Library databases up to July 2019. Eligible in vitro studies needed to include assessments of the apoptosis rate by flow cytometry using annexin V/propidium iodide, and studies in animal models and clinical trials needed to examine tumor inhibition rates, and progression-free survival (PFS) and overall survival (OS), respectively. Data were analyzed using descriptive statistics.

RESULTS

Overall, 35 studies, i.e., 21 performed in vitro, 11 based on animal models, and three clinical trials, were finally included. In vitro and animal studies indicated that DSF was associated with enhanced apoptosis and tumor inhibition rates, separately. Human studies showed that DSF prolongs PFS and OS. The greatest anti-tumor activity was observed when DSF was used as combination therapy or as a nanoparticle-encapsulated molecule. There was no noticeable body weight loss after DSF treatment, which indicated that there was no major toxicity of DSF.

CONCLUSIONS

This systematic review provides evidence regarding the anti-tumor activity of DSF in vitro, in animals, and in humans and indicates the optimal forms of treatment to be evaluated in future research.

Direct targeted therapy for MLL-fusion-driven high-risk acute leukaemias

BACKGROUND

Improving the poor prognosis of infant leukaemias remains an unmet clinical need. This disease is a prototypical fusion oncoprotein-driven paediatric cancer, with MLL (KMT2A)-fusions present in most cases. Direct targeting of these driving oncoproteins represents a unique therapeutic opportunity. This rationale led us to initiate a drug screening with the aim of discovering drugs that can block MLL-fusion oncoproteins.

METHODS

A screen for inhibition of MLL-fusion proteins was developed that overcomes the traditional limitations of targeting transcription factors. This luciferase reporter-based screen, together with a secondary western blot screen, was used to prioritize compounds. We characterized the lead compound, disulfiram (DSF), based on its efficient ablation of MLL-fusion proteins. The consequences of drug-induced MLL-fusion inhibition were confirmed by cell proliferation, colony formation, apoptosis assays, RT-qPCR, in vivo assays, RNA-seq and ChIP-qPCR and ChIP-seq analysis. All statistical tests were two-sided.

RESULTS

Drug-induced inhibition of MLL-fusion proteins by DSF resulted in a specific block of colony formation in MLL-rearranged cells in vitro, induced differentiation and impeded leukaemia progression in vivo. Mechanistically, DSF abrogates MLL-fusion protein binding to DNA, resulting in epigenetic changes and down-regulation of leukaemic programmes setup by the MLL-fusion protein.

CONCLUSION

DSF can directly inhibit MLL-fusion proteins and demonstrate antitumour activity both in vitro and in vivo, providing, to our knowledge, the first evidence for a therapy that directly targets the initiating oncogenic MLL-fusion protein.

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.

Leveraging disulfiram to treat cancer: Mechanisms of action, delivery strategies, and treatment regimens

Disulfiram (DSF) has been used as an alcoholism drug for 70 years. Recently, it has attracted increasing attention owing to the distinguished anticancer activity, which can be further potentiated by the supplementation of Cu²⁺. Although encouraging anticancer results are obtained in lab, the clinical outcomes of oral DSF are not satisfactory, which urges an in-depth understanding of the underlying mechanisms, bottlenecks, and proposal of potential methods to address the dilemma. In this review, a critical summarization of various molecular biological anticancer mechanisms of DSF/Cu²⁺ is provided and the predicament of orally delivering DSF in clinical oncotherapy is explained by the metabolic barriers. We highlight the recent advances in the DSF/Cu²⁺ delivery strategies and the emerging treatment regimens for cancer treatment. Last but not the least, we summarize the clinical trials regarding DSF and make a prospect of DSF/Cu-based cancer therapy.

Repurposing Disulfiram for Targeting of Glioblastoma Stem Cells: An In Vitro Study

Mesenchymal glioblastoma stem cells (GSCs), a subpopulation in glioblastoma that are responsible for therapy resistance and tumor spreading in the brain, reportedly upregulate aldehyde dehydrogenase isoform-1A3 (ALDH1A3) which can be inhibited by disulfiram (DSF), an FDA-approved drug formerly prescribed in alcohol use disorder. Reportedly, DSF in combination with Cu2+ ions exerts multiple tumoricidal, chemo- and radio-therapy-sensitizing effects in several tumor entities. The present study aimed to quantify these DSF effects in glioblastoma stem cells in vitro, regarding dependence on ALDH1A3 expression. To this end, two patient-derived GSC cultures with differing ALDH1A3 expression were pretreated (in the presence of CuSO4, 100 nM) with DSF (0 or 100 nM) and the DNA-alkylating agent temozolomide (0 or 30 µM) and then cells were irradiated with a single dose of 0-8 Gy. As read-outs, cell cycle distribution and clonogenic survival were determined by flow cytometry and limited dilution assay, respectively. As a result, DSF modulated cell cycle distribution in both GSC cultures and dramatically decreased clonogenic survival independently of ALDH1A3 expression. This effect was additive to the impairment of clonogenic survival by radiation, but not associated with radiosensitization. Of note, cotreatment with temozolomide blunted the DSF inhibition of clonogenic survival. In conclusion, DSF targets GSCs independent of ALDH1A3 expression, suggesting a therapeutic efficacy also in glioblastomas with low mesenchymal GSC populations. As temozolomide somehow antagonized the DSF effects, strategies for future combination of DSF with the adjuvant standard therapy (fractionated radiotherapy and concomitant temozolomide chemotherapy followed by temozolomide maintenance therapy) are not supported by the present study.

Quantitative proteomics analysis reveals novel insights into mechanisms of action of disulfiram (DSF)

PURPOSE

Disulfiram (DSF) has been proven safe and shows the promising antitumor effect in preclinical studies. However, the precise mechanism of DSF on tumor is rarely reported. This study aims to fully understand the mechanism of action of DSF with a systems perspective in anticancer effects.

EXPERIMENTAL DESIGN

SILAC-based quantitative proteomics strategy was used to systematically identify differential expression proteins (DEPs) after DSF treatment in HeLa cells. Bioinformatical analysis (PANTHER, DAVID, and STRING) were performed to characterize biological functions of DEPs. Functional studies were performed to explore underlying mechanisms of DSF in cancer cells.

RESULTS

In total, 201 proteins were dysregulated significantly after DSF exposure. Functional studies of hexokinase 2 (HK2), which catalyzed the first irreversible enzymatic step in glucose metabolism, revealed that various phenotypic effects observed after DSF treatment in cancer cells, at least partly, through the regulation of HK2 expression.

CONCLUSIONS AND CLINICAL RELEVANCE

By correlating the proteomics data with these functional studies, the current results provided novel insights into the mechanism underlying DSF function in cancer cells. Meanwhile, these provided theoretical basis for the new use of old drugs in clinical therapy.

Non-epigenetic induction of HEXIM1 by DNMT1 inhibitors and functional relevance

We have been studying the role of Hexamethylene bisacetamide (HMBA) Induced Protein 1 (HEXIM1) as a tumor suppressor whose expression is decreased in breast and prostate cancer. The anti-cancer actions of HEXIM1 in melanomas and AML have been reported by other groups. Previous studies have shown that 5-Aza-2'deoxycytidine (5-AzadC), a DNMT1 inhibitor, induces re-expression of tumor suppressor genes by removing/erasing methylation marks from their promoters. Our studies highlighted another mechanism wherein 5-AzadC induced DNA damage, which then resulted in enhanced occupancy of NF-ĸB, P-TEFb, and serine 2 phosphorylated RNA Polymerase II on the HEXIM1 gene. As a consequence, 5-AzadC induced HEXIM1 expression in prostate cancer cell lines and triple negative breast cancers. 5-AzadC-induced DNA damage enhanced P-TEFb occupancy via a mechanism that involved activation of ATR and ATM and induction of NF-ĸB recruitment to the HEXIM1 promoter. Downregulation of NF-ĸB attenuated 5-AzadC-induced HEXIM1 expression in prostate and breast cancer cells. The functional relevance of 5-AzadC-induced HEXIM1 expression is revealed by studies showing the HEXIM1 is required for the induction of apoptosis. Collectively, our findings support a non-epigenetic mechanism for 5-AzadC-induced re-expression of HEXIM1 protein, and may contribute to the clinical efficacy of 5-AzadC.

Thermosensitive Chitosan-Based Injectable Hydrogel as an Efficient Anticancer Drug Carrier

A thermosensitive, physically cross-linked injectable hydrogel was formulated for the effective and sustained delivery of disulfiram (DSF) to the cancer cells as there is no hydrogel formulation available until now for the delivery of DSF. As we know, hydrogels have an advantage over other drug delivery systems because of their unique properties, so we proposed to formulate an injectable hydrogel system for the sustained delivery of an anticancer drug (DSF) to cancer cells. To investigate the surface morphology, a scanning electron microscope study was carried out, and for thermal stability of hydrogels, TGA (thermogravimetric analysis) and DSC (differential scanning calorimetry) were performed. The rheological behavior of hydrogels was evaluated with the increasing temperature and time. These developed hydrogels possessing excellent biocompatibility could be injected at room temperature following rapid gel formation at body temperature. The swelling index and in vitro drug release studies were performed at different pH (6.8 and 7.4) and temperatures (25 and 37 °C). The cell viability of the blank hydrogel, free DSF solution, and Ch/DSF (chitosan/DSF)-loaded hydrogel was studied by MTT assay on SMMC-7721 cells for 24 and 48 h, which exhibited higher cytotoxicity in a dose-dependent manner in contrast to the free DSF solution. Moreover, the cellular uptake of DSF-loaded hydrogels was observed stronger as compared with free DSF. Hence, chitosan-based hydrogels loaded with DSF possessing exceptional properties can be used as a novel injectable anticancer drug for the sustained delivery of DSF for long-term cancer therapy.

The combination of disulfiram and copper for cancer treatment

Disulfiram (DSF) is a thiuram derivative that was developed to treat alcoholism but was also found to have antitumor activity. Copper (Cu), as a trace metal, has important roles in the body. Numerous studies have shown that the combination of DSF and copper (DSF/Cu) greatly enhances its antitumor efficacy. Given that the efficacy of DSF is well established and its safety profile is understood, repurposing DSF as a new anticancer drug is a promising strategy. Here, we summarize the pharmacological effects of DSF and the role of Cu in cancer, and focus on the antitumor effect of DSF/Cu, especially the mechanisms involved in enhancing drug sensibility by targeting specific molecules. We also provide rational strategies for using DSF as a cancer therapy.

Disulfiram/Copper Induces Antitumor Activity against Both Nasopharyngeal Cancer Cells and Cancer-Associated Fibroblasts through ROS/MAPK and Ferroptosis Pathways

Disulfiram/copper (DSF/Cu) is a promising antitumor reagent for clinical application due to its excellent anticancer activity and safety. However, the anticancer mechanism of DSF/Cu has not been fully elucidated. Our study showed that DSF/Cu strongly induced cytotoxic effects on both nasopharyngeal carcinoma (NPC) cells and α-smooth muscle actin (α-SMA)-positive fibroblasts. Fluorescence activated cell sorting (FACS) analysis further showed that DSF/Cu induced a higher late apoptosis rate in α-SMA-positive fibroblasts than in tumor cells, and DSF/Cu promoted apoptosis and necrosis by an aldehyde dehydrogenase (ALDH)-independent method. Furthermore, we found that the antitumor activity of DSF/Cu against NPC cells occurred through ROS/MAPK and p53-mediated ferroptosis pathways, and that the ROS scavenger N-acetyl-l-cysteine (NAC) could reverse the cellular and lipid ROS levels. In 5-8F xenografts, both TUNEL and immunohistochemical (IHC) analyses indicated that DSF/Cu could induce apoptosis and inactivate cancer-associated fibroblasts (CAFs) by inhibiting the expression of α-SMA. In addition, combined with cisplatin (CDDP), DSF/Cu was well tolerated in vivo and could significantly suppress the growth of NPC tissues. Our study demonstrated that DSF/Cu induced antitumor activity against both tumor cells, as well as CAFs and suggested that the use of DSF/Cu as an adjunctive therapy for NPC is worthy of consideration.

Recent advances in the delivery of disulfiram: a critical analysis of promising approaches to improve its pharmacokinetic profile and anticancer efficacy

BACKGROUND

Disulfiram (DSF) has a long history of being used as a first-line promising therapy for treatment of alcoholism in human. Besides its prominence in the treatment of alcoholism, extensive investigations have been carried out to explore other biomedical and pharmacological effects of DSF. Amongst other biomedical implications, plenty researches have shown evidence of promising anticancer efficacy of this agent for treatment of wide range of cancers such as breast cancer, liver cancer and lung carcinoma.

METHODS

Electronic databases, including Google scholar, PubMed and Web of science were searched with the keywords disulfiram, nanoparticles, cancer, drug delivery systems.

RESULT

Despite its excellent anticancer efficacy, the pharmaceutical significance and clinical applicability of DSF are hampered due to poor stability, low solubility, short plasma half-life, rapid metabolism, and early clearance from systemic circulation. Various attempts have been made to eradicate these issues. Nanotechnology based interventions have gained remarkable recognition in improving pharmacokinetic and pharmacodynamic profile of DSF by improving its stability and avoiding its degradation.

CONCLUSION

The aim of the present review is to critically analyse all recent developments in designing various nanotechnology-based delivery systems, to ponder their relevance in improving stability, pharmacokinetic and pharmacodynamic profile, and achieving target-specific delivery of this agent to cancer cells to effectively eradicate cancer and abolish its metastasis. Nanotechnology is a novel approach for overcoming such obstacles faced presently, the results obtained so far using different novel drug delivery systems seem to be very promising to increase the stability and half-life of DSF. Graphical abstract Nanocrrier mediated drug delivery systems for disulfiram.

Knockdown of estrogen receptor β increases proliferation and affects the transcriptome of endometrial adenocarcinoma cells

Background

Estrogen receptor β (ERβ) has been repeatedly suggested to play important roles in hormone-dependent cancer like in tumors of the breast, ovary or prostate. In this study, we intended to further elucidate its role in endometrial cancer.

Methods

For this purpose, we knocked down ERβ expression in two endometrial cancer cell lines, the ERα-negative/ERβ-positive line HEC-1A and the ERα/β-positive cell line RL95/2, by means of siRNA transfection. Cell proliferation after transfection was assessed using the fluorescent CTB Assay (Promega). In order to elucidate possible molecular mechanisms which might underlie the effect on proliferation, we performed transcriptome analyses by means of human Affymetrix Human Gene Chip 2.0. Additionally, we treated the employed cell lines with different ERβ modulators to examine their effect on proliferation.

Results

siRNA-mediated knockdown of ERβ significantly increased proliferation of both endometrial cancer cell lines. In HEC-1A cells, proliferation was significantly increased 4, 5 and 6 days after transfection, with a maximum of about 1.7-fold (p < 0.05) on day 6. Endometrial RL95/2 cells with an ERβ knockdown exhibited a clearly enhanced proliferation on day 3 and days 4 to 8, when even 2.4-fold higher numbers of viable cells were detected (p < 0.01). Transcriptome analysis revealed that this was accompanied by increased expression of several genes being known to be upregulated in cancer, including proliferation-associated genes and oncogenes, and by repression of genes associated with differentiation, apoptosis or growth inhibition. Corroborating the observed knockdown effects, treatment with the ERβ antagonists PHTTP and (R, R) THC was also able to induce proliferation of both cell lines.

Conclusions

Our data clearly support the putative role of ERβ as tumor suppressor in endometrium as previously suggested in studies on other tissues and encourage further studies to find out to what extent this molecule might be a potential therapy target in this cancer entity.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5928-2) contains supplementary material, which is available to authorized users.

Drugs Targeting Epigenetic Modifications and Plausible Therapeutic Strategies Against Colorectal Cancer

Genetic variations along with epigenetic modifications of DNA are involved in colorectal cancer (CRC) development and progression. CRC is the fourth leading cause of cancer-related deaths worldwide. Initiation and progression of CRC is the cumulation of a variety of genetic and epigenetic changes in colonic epithelial cells. Colorectal carcinogenesis is associated with epigenetic aberrations including DNA methylation, histone modifications, chromatin remodeling, and non-coding RNAs. Recently, epigenetic modifications have been identified like association of hypermethylated gene Claudin11 (CLDN11) with metastasis and prognosis of poor survival of CRC. DNA methylation of genes CMTM3, SSTR2, MDF1, NDRG4 and TGFB2 are potential epigenetic biomarkers for the early detection of CRC. Tumor suppressor candidate 3 (TUSC3) mRNA expression is silenced by promoter methylation, which promotes epidermal growth factor receptor (EGFR) signaling and rescues the CRC cells from apoptosis and hence leading to poor survival rate. Previous scientific evidences strongly suggest epigenetic modifications that contribute to anticancer drug resistance. Recent research studies emphasize development of drugs targeting histone deacetylases (HDACs) and DNA methyltransferase inhibitors as an emerging anticancer strategy. This review covers potential epigenetic modification targeting chemotherapeutic drugs and probable implementation for the treatment of CRC, which offers a strong rationale to explore therapeutic strategies and provides a basis to develop potent antitumor drugs.

Estrogens and prostate cancer

BACKGROUND

Hormonal influences such as androgens and estrogens are known contributors in the development and progression of prostate cancer (CaP). While much of the research to the hormonal nature of CaP has focused on androgens, estrogens also have critical roles in CaP development, physiology as well as a potential therapeutic intervention.

METHODS

In this review, we provide a critical literature review of the current basic science and clinical evidence for the interaction between estrogens and CaP.

RESULTS

Estrogenic influences in CaP include synthetic, endogenous, fungi and plant-derived compounds, and represent a family of sex hormones, which cross hydrophobic cell membranes and bind to membrane-associated receptors and estrogen receptors that localize to the nucleus triggering changes in gene expression in various organ systems.

CONCLUSIONS

Estrogens represent a under-recognized contributor in CaP development and progression. Further research in this topic may provide opportunities for identification of environmental influencers as well as providing novel therapeutic targets in the treatment of CaP.

Disulfiram-loaded mixed nanoparticles with high drug-loading and plasma stability by reducing the core crystallinity for intravenous delivery

To develop an injectable formulation and improve the stability of disulfiram (DSF), DSF was encapsulated into mixed nanoparticles (DSF-NPs) through a high-pressure homogenization method. The Flory-Huggins interaction parameters (χ_FH) were calculated to predict the miscibility between DSF and the hydrophobic core, resulting in PCL₅₀₀₀ selected as the hydrophobic block to encapsulate the DSF, as PCL₅₀₀₀ had a lower χ_FH 3.39 and the drug loading of the nanoparticles prepared by mPEG₅₀₀₀-PCL₅₀₀₀ was relatively higher. mPEG₅₀₀₀-PCL₅₀₀₀ and PCL₅₀₀₀ were blended to reduce the leakage of DSF during preparation, as well as increase the stability of the nanoparticles. The cargo-loading capacity of the nanoparticles was improved from 3.35% to 5.50% by reducing the crystallinity of the PCL nanoparticle core, and the crystallinity decreased from 51.13% to 25.15% after adding medium chain triglyceride (MCT). The DSF-NPs prepared by the above method had a small particle size of 98.1 ± 10.54 nm, with a polydispersity index (PDI) of 0.036, as well as drug loading of 5.50%. Furthermore, DSF-NPs containing MCT showed higher stability than DSF-NPs without MCT and DSF-sol (DSF dissolved in Cremophor EL and ethanol) in water and 90% plasma-containing PBS. The pharmacokinetics proved that DSF-NPs containing MCT enhanced the DSF concentration in the blood. Finally, DSF-NPs effectively inhibited H22 xenograft tumor growth in vivo.

Targeting DNA Methyltranferases in Urological Tumors

Urological cancers are a heterogeneous group of malignancies accounting for a considerable proportion of cancer-related morbidity and mortality worldwide. Aberrant epigenetic traits, especially altered DNA methylation patterns constitute a hallmark of these tumors. Nonetheless, these alterations are reversible, and several efforts have been carried out to design and test several epigenetic compounds that might reprogram tumor cell phenotype back to a normal state. Indeed, several DNMT inhibitors are currently under evaluation for therapeutic efficacy in clinical trials. This review highlights the critical role of DNA methylation in urological cancers and summarizes the available data on pre-clinical assays and clinical trials with DNMT inhibitors in bladder, kidney, prostate, and testicular germ cell cancers.

Anti-hepatocellular carcinoma properties of the anti-alcoholism drug disulfiram discovered to enzymatically inhibit the AMPK-related kinase SNARK in vitro

We recently described that the anti-apoptotic AMPK-related kinase, SNARK, promotes transforming growth factor (TGF)-β signaling in hepatocellular carcinoma (HCC) cells, as a potentially new therapeutic target. Here we explored FDA-approved drugs inhibiting the enzymatic activity of SNARK, using an in vitro luminescence kinase assay system. Interestingly, the long-used anti-alcoholism drug disulfiram (DSF), also known as Antabuse, emerged as the top hit. Enzymatic kinetics analyses revealed that DSF inhibited SNARK kinase activity in a noncompetitive manner to ATP or phosphosubstrates. Comparative in vitro analyses of DSF analogs indicated the significance of the disulfide bond-based molecular integrity for the kinase inhibition. DSF suppressed SNARK-promoted TGF-β signaling and demonstrated anti-HCC effects. The chemical and enzymatic findings herein reveal novel pharmacological effects of and use for DSF and its derivatives, and could be conducive to prevention and inhibition of liver fibrosis and HCC.

Disulfiram with or without metformin inhibits oesophageal squamous cell carcinoma in vivo

Oesophageal squamous cell carcinoma (OSCC) is highly prevalent in developing countries but there has been little recent progress into efficacious yet affordable treatment strategies. Drug repurposing is one attractive approach for cancer therapy. Disulfiram (DSF), used to treat alcoholism, inhibits cancer growth and we previously found that DSF perturbs protein degradation/turnover pathways in vitro. This was enhanced by combining DSF with the anti-diabetic drug metformin (Met). Here, we investigated DSF with/without Met, against OSCC in vivo. Nude mice injected subcutaneously with the human OSCC cell line WHCO1, were treated with 30 mg/kg or 50 mg/kg DSF three times per week and with/without Met, for 21 days. DSF and DSF/Met-treated animals had significantly smaller tumours compared to untreated, vehicle and positive control cisplatin-treated groups. This effect for DSF was independent of copper, with no significant accumulation of copper in tumours, together with maintained proteasome activity. However, increases in total ubiquitinated proteins, LC3B-II, LAMP1 and p62 in DSF and DSF/Met groups, indicate that autophagy is inhibited. These findings show that DSF and DSF/Met significantly impede OSCC tumour growth in vivo and offer prospective alternative chemotherapy approaches for OSCC.

Disulfiram chelated with copper promotes apoptosis in human breast cancer cells by impairing the mitochondria functions

Disulfiram (DSF) has been proved to have broad-spectrum anti-alcoholism effects, and it is also found to show stronger anti-tumor effects after chelating with Cu²⁺ to form DSF-Cu complex. In this work, we studied the anti-tumor activity of DSF-Cu in MCF-7 cells by flow cytometry, confocal laser scanning microscope, and atomic force microscopy to clarify the underlying anti-tumor mechanisms. MCF-7 cells were incubated with 50, 100, 150, 200, and 250 nM DSF chelated with 10 µM CuCl₂ for 24 h. The results showed that DSF-Cu could induce the accumulation of MCF-7 cells in G2/M phase and apoptosis in a concentration-dependent manner. Additionally, atomic force microscope (AFM) analysis at nanoscale level showed that the morphology of cell was significantly shrunk with destroyed filopodia and ultrastructure presented many irregular protuberances on the cell membrane after DSF-Cu treatment, which was closely associated with the re-arrangement of cytoskeleton. DSF-Cu induced the production of reactive oxygen species (ROS), increased the concentration of intracellular Ca²⁺ and decreased the mitochondrial membrane potential (MMP) in MCF-7 cells resulting in a mitochondria-dependent apoptosis pathway. The results indicated that DSF-Cu has a potential anti-tumor activity in breast cancer by impairing the mitochondria functions. SCANNING 38:825-836, 2016. © 2016 Wiley Periodicals, Inc.

Epigenetic modulators as therapeutic targets in prostate cancer

Prostate cancer is one of the most common non-cutaneous malignancies among men worldwide. Epigenetic aberrations, including changes in DNA methylation patterns and/or histone modifications, are key drivers of prostate carcinogenesis. These epigenetic defects might be due to deregulated function and/or expression of the epigenetic machinery, affecting the expression of several important genes. Remarkably, epigenetic modifications are reversible and numerous compounds that target the epigenetic enzymes and regulatory proteins were reported to be effective in cancer growth control. In fact, some of these drugs are already being tested in clinical trials. This review discusses the most important epigenetic alterations in prostate cancer, highlighting the role of epigenetic modulating compounds in pre-clinical and clinical trials as potential therapeutic agents for prostate cancer management.

Cholesterol biosynthesis inhibitor RO 48-8071 suppresses growth of hormone-dependent and castration-resistant prostate cancer cells

Standard treatment for primary prostate cancer includes systemic exposure to chemotherapeutic drugs that target androgen receptor or antihormone therapy (chemical castration); however, drug-resistant cancer cells generally emerge during treatment, limiting the continued use of systemic chemotherapy. Patients are then treated with more toxic standard therapies. Therefore, there is an urgent need for novel and more effective treatments for prostate cancer. The cholesterol biosynthetic pathway is an attractive therapeutic target for treating endocrine-dependent cancers because cholesterol is an essential structural and functional component of cell membranes as well as the metabolic precursor of endogenous steroid hormones. In this study, we have examined the effects of RO 48-8071 (4′-[6-(allylmethylamino)hexyloxy]-4-bromo-2′-fluorobenzophenone fumarate; Roche Pharmaceuticals internal reference: RO0488071) (RO), which is an inhibitor of 2, 3-oxidosqualene cyclase (a key enzyme in the cholesterol biosynthetic pathway), on prostate cancer cells. Exposure of both hormone-dependent and castration-resistant human prostate cancer cells to RO reduced prostate cancer cell viability and induced apoptosis in vitro. RO treatment reduced androgen receptor protein expression in hormone-dependent prostate cancer cells and increased estrogen receptor β (ERβ) protein expression in both hormone-dependent and castration-resistant prostate cancer cell lines. Combining RO with an ERβ agonist increased its ability to reduce castration-resistant prostate cancer cell viability. In addition, RO effectively suppressed the growth of aggressive castration-resistant human prostate cancer cell xenografts in vivo without any signs of toxicity to experimental animals. Importantly, RO did not reduce the viability of normal prostate cells in vitro. Our study is the first to demonstrate that the cholesterol biosynthesis inhibitor RO effectively suppresses growth of human prostate cancer cells. Our findings suggest that cholesterol biosynthesis inhibitors such as RO, when used in combination with commonly used chemotherapeutic drugs or ERβ specific ligands, could represent a novel therapeutic approach to prevent the growth of prostate cancer tumors.