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INTRODUCTION Prostate cancer (PCa) is the most common cancer in the North-American man. It was responsible for about 192,000 new cases and 33,000 deaths in the USA in 2020. Surgical resection and systemic androgen deprivation therapy are standard approaches to treat both localized and metastatic PCa (mPCa). The five-year survival from prostate cancer (PCa) without bone metastasis is 56% versus 3% with metastasis There is no cure for the metastatic prostate cancer (mPCa) which often spreads to the hip, spine, and pelvis bones. Therefore, new approaches and combination therapy need to be developed to improve patients's survival. Disulfiram's anti-cancer activity was previously explored and its metabolite ditiocarb-copper complex (CuET) was found to have high anti-cancer activity. The mechanism of action of CuET involves NPL4 aggregation and activation of ER stress, leading to preferential apoptosis of cancer cells. Since altered protein degradation is targeted by CuET, it might display high efficacy in highly mutated PCa. Consequently, we want to propose CuET for the treatment of mPCa. METHODS Survival curve and colony-formation assays in murine dKO cell line harboring PTEN and Rb driver mutations as well as in the human metastatic PC3 cell line, were performed. Anti-metastatic effect of CuET in vitro was assessed through Boyden chamber. In vivo efficacy of systemic treatment with CuET, was studied in dKO model of C57BL/6 mice. RESULTS Our results demonstrate that CuET displays cytotoxicity in dKO and PC3 cells at very low concentrations with respective IC50 of 46.2nM and 90.5nM. In vitro, CuET significantly reduced both the clonogenicity and migration ability of cells. In vivo, systemic treatment with CuET significantly reduced growth of dKO tumor and prevented recurrence of tumors. CONCLUSION Given these positive pre-clinical results, CuET should be investigated for its antineoplastic activity in clinical setting as an adjuvant therapy for mPCa. Citation Format: Daciana Catalina Dumut, Juan B. DeSanctis, Martin Mistrik, Zdenek Skrott, Petr Dzubak, Jiri Bartek, Marian Hajduch, Danuta Radzioch. Dithiocarb-copper complex, CuET, demonstrates anti-neoplastic activity in mouse model of prostate cancer and prevents recurrence of tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1251. more...

Introduction: Colorectal cancer (CRC) is the third leading cause of cancer related deaths in the United States. It was responsible for about 51,000 deaths during 2019. Surgical resection and systemic chemotherapy are standard approaches to treat both localized and metastatic CRC (mCRC). However, the effect of the chemotherapy depends on the characteristics of the individual tumor, for instance CRC subtypes with a microsatellite instability (MSI) tend to have better prognosis and response to both chemotherapy and immune check-point inhibition. Recently, Disulfiram's anti-cancer activity was explored and its metabolite ditiocarb-copper complex (CuET) was found to have high anti-cancer activity. The mechanism of action of CuET was proposed to act through p97 segregase adaptor NPL4 and activation of endoplasmic reticulum stress leading to preferential apoptosis of cancer cells. Since altered protein degradation pathway is targeted by CuET, this compound might display high efficacy in highly mutated colorectal cancers. Methods: To assess CuET anti-cancer activity in vitro, we performed survival curve assays and colony-formation assays in both murine hypermutated colorectal cancer cell line MC-38 as well as in human KRAS mutant and MSI HCT116 cell line. We also evaluated anti-metastatic effect of CuET on both cell lines through migration-invasion assays in Boyden chamber setting. We assessed in vivo efficacy of systemic treatment with CuET alone or in combination with irinotecan, against MC-38 model in immunocompetent C57BL/6 mice. We characterized tumor growth, mice survival and tumor histopathology. Results: Our results demonstrate that CuET displays cytotoxicity in MC-38 and HCT116 cells at very low doses with respective IC50 of 46nM and 88nM. CuET also significantly reduces the ability of both cell lines to grow and form colonies under sustained treatment. Additionally, CuET is effective in significantly reducing cancer cell migration and invasion through porous membrane in vitro. Furthermore, systemic treatment with CuET significantly reduced tumor growth in mice and prolonged survival when compared to controls. Conclusion: CuET demonstrates cytotoxic activity against hypermutated colorectal cancer cells both in vitro and in vivo and should be further investigated in clinical trials. Citation Format: Daciana Catalina Dumut, Juan B. De Sanctis, Martin Mistrik, Zdenek Skrott, Petr Dzubak, Jiri Bartek, Marian Hajduch, Danuta Radzioch. Disulfiram anticancer metabolite, dithiocarb-copper complex, demonstrates anti-neoplastic activity against hypermutated colorectal cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5246. more...

In patients with thallium poisoning, treated with the chelating agent sodium diethyldithiocarbamate (dithiocarb), clinical deterioration and electroencephalographic disturbances have been observed coincident with the periods in which dithiocarb was given. Intravenous administration of dithiocarb to rats poisoned with thallium causes redistribution of thallium in the chelate form, with an increase of concentration in the brain. The chelate formed is rapidly decomposed again. These observations constitute a contraindication to the use of dithiocarb as an antidote in thallium poisoning. more...

In phenobarbital (phenemalum NFN)-pretreated male rats exposed to 1% halothane for 2 hrs under hypoxic conditions (10% 02), significant increases in serum enzyme activities of alanine aminotransferase and sorbitol dehydrogenase were observed 24 and 48 hrs later indicating liver damage. In this known model of halothane hepatotoxicity, pretreatment with (+)-catechin (200 mg/kg orally) or silybine (150 mg/kg orally) protected against halothane-induced liver injury, whereas diethyldithiocarbamate (200 mg/kg orally) failed to be effective. Halothane decreased the concentration of reduced glutathione in liver only under hypoxic conditions indicating that glutathione might be involved in the non-oxidative metabolic pathways of halothane. Free fluoride in plasma was used as a measure of non-oxidative defluorination of halothane. Higher plasma fluoride levels were observed under conditions which led to hepatotoxicity but did not correlate with the protective effects of the antidotes. This further supports the assumption that 2-chloro-1,1,1-trifluoroethane might be the radical intermediate responsible for halothane hepatotoxicity. more...

60 patients with HIV-1 infection in Walter Reed stages 2-4 were randomised to treatment with intravenous or oral dithiocarb (diethyldithiocarbamate, DTC) or placebo for 24 weeks in a paired double-blind design. 55 patients were evaluable at the end of the study: no patient who had received DTC but 6 placebo patients had AIDS, a significant difference. Significantly delayed disease progression was observed in the intravenous DTC group compared with its matching placebo. The benefit in the oral DTC group was not statistically significant. During an 18-month follow-up 3 deaths occurred in the original placebo groups, whereas no patient who had initially received DTC died. A significant delay in progression to AIDS was observed in the DTC groups. more...

Hepatotoxicity of vinylidene chloride (1, 1-dichloroethylene, VDC) in rats was evidenced by increases of serum enzyme activities of the aminotransferases (GOT, GPT) and sorbitol dehydrogenase (SDH). Simultaneous treatment with ethanol (4.8 g kg-1; p.o.) totally inhibited these hepatotoxic effects, whereas pretreatment with the same ethanol dose 24 h prior to VDC had no effect. Dithiocarb or (+)-catechin (0.2 g kg-1; p.o.), administered simultaneously with VDC, significantly reduced the VDC-induced increments of serum enzyme activities. Pretreatment with 5% ethanol for 7 days instead of drinking water increased the hepatotoxicity of a single dose of VDC. The combined treatment with VDC (0.125-0.2 g kg-1, twice weekly) and 5% ethanol for 4 weeks led to only small increases of serum enzyme activities as compared with controls treated with VDC alone. However, 60% lethality occurred in the VDC-ethanol group. Administration of either dithiocarb or (+)-catechin with VDC totally antagonized the observed lethality. Metabolic studies with VDC in a closed exposure system indicated that simultaneous treatment with ethanol or dithiocarb totally depressed the metabolic removal of VDC, whereas (+)-catechin had no effect. more...

The present study describes the inhibitory effects of diethyldithiocarbamate (dithiocarb) on the metabolic elimination of hexobarbital, phenazone, tolbutamide and four halogenated hydrocarbons. The plasma half-life for the beta-slopes of hexobarbital (25 mg/kg, i.v.) and phenazone (50 mg/kg, i.v.) were increased 2.5 and 3.5 fold respectively, when dithiocarb (100 mg/kg, i.p.) was administered simultaneously. The plasma half-life of tolbutamide was 2.27 h, when administered alone to rats; and 4.04 h, when administered with dithiocarb. Metabolic elimination of halothane, trichloroethylene, dichloroethane, and carbon tetrachloride, from the atmosphere of a closed exposure system was studied in rats. Treatment with dithiocarb (100 mg/kg, i.p.) immediately before exposure, prolonged the elimination half-life of: halothane (103 parts/10(6)) by a factor of 7.6, of trichloroethylene (25 parts/10(6)) by a factor of 5.3; dichloroethane (69 parts/10(6)) by 4.6; and carbon tetrachloride (38 parts/10(6)) by 2.4, respectively. The inhibitory actions of dithiocarb on the metabolism of the tested drugs and chemicals are explained as the consequences of a depressed microsomal mono-oxygenase activity due to a decrease in the cytochrome P 450 content. more...

The influence of intravenously administered mixtures of paraquat and the chelating agents CaNa 2 -EDTA or dithiocarb on the toxicity of oxygen at normal pressure was studied in rats. No increase in toxic effects of the combination paraquat-oxygen was seen by additionally administered chelate-forming agents. This paper completes the investigations on oxygen toxicity after administration of various chelate-forming agents in mice 1 . more...

Dithiocarb and (+)-cyanidanol-3-prevented paracetamol-induced liver injury in rats in vivo. Both, as well as two other antihepatotoxic agents, deanol and DMSO, inhibited covalent binding of [3H]-paracetamol to rat liver microsomal proteins in vitro. Dithiocarb and (+)-cyanidanol-3 were the most effective inhibitors. The concentrations of the antidotes yielding 50% inhibition (I50) valued 1 . 8 x 10(-5) M for dithiocarb and 2 . 1 x 10(-5) M for (+)-cyanidanol-3. more...

During intoxications with paracetamol hepatic and renal failure may develop, the latter also in the absence of liver damage (Boyer et al., 1971; Prescott et al., 1971; Cobden et al., 1982). Several antidotes are available for the treatment of severe paracetamol poisoning, these include mainly precursors of GSH-synthesis like methionine or N-acetylcysteine (Crome et al,. 1976; Prescott et al., 1977). In animal experiments diethyldithiocarbamate (dithiocarb) was shown to be an effective antidote against paracetamol-induced hepatotoxicity, due to its strong inhibitory influence on microsomal monooxygenases (Strubelt et al., 1974; Siegers et al., 1982). No experimental or clinical data, however, are available proving the efficacy of these antidotes in preventing paracetamol-induced renal damage. Moreover, it is still unclear, whether the metabolic pathways leading to hepatotoxic intermediates of paracetamol are the same for exerting nephrotoxic response. more...

1. After i.p. injection of [2,3-14C]acrylonitrile to rats, a significant portion of radioactivity becomes irreversibly attached to proteins of liver, lung, spleen and other tissues. 2. When rat liver microsomes were incubated with [2,3-14C]acrylonitrile, a time-dependent irreversible binding of radioactivity occurred to microsomal proteins. This binding was not dependent on NADPH. A high extent of binding to heat-inactivated microsomes indicated that no enzymic metabolic step was involved. 3. The irreversible binding of [2,3-14C]acrylonitrile to rat liver microsomal protein in vitro was inhibited by thiols (cysteine, glutathione, mercaptoethanol). The greatest inhibitory potency was displayed by dithiocarb (diethyl dithiocarbamate). more...

Immune impairment or dysfunction is associated with cancers, and is frequently aggravated by conventional therapies. As a consequence, the development of agents active on the immune system in ways that restore or regulate host defenses, has become a major objective. An overall appreciation of the published data led us to conceptualize the following requirements for suitable immunopharmacologic agents. Absence of carcinogenicity, of tumor promoting influence and of antigenicity or sensitizing effects, is an essential prerequisite since these agents will be administered for long periods of time to patients already at risk. They should have defined influences on populations or subpopulations of immunocompetent cells, as their essential activities. Their toxic levels and pharmacologic effects should be known to delineate the range of doses and predict most side effects. Such requirements will reasonably eliminate most of the inconsistencies which have somewhat dampened confidence in therapies intended to modify the immune system. more...

A dose-dependent increase of paracetamol serum half-life (t1/2) was found after oral and intravenous application in rats and oral application in mice. The hepatotoxic effects of paracetamol were not correlated with this prolongation of t1/2. Dithiocarb protected rats against paracetamol liver damage but did not change paracetamol t1/2. Paracetamol t1/2 was not influenced either by a hepatotoxic dose of carbon tetrachloride. In conclusion, the dose-dependent prolongation of paracetamol serum half-life is not due to paracetamol-induced liver damage but merely the consequence of saturated elimination processes. more...

Metabolic balance studies carried out on a thirty-four year old woman with Wilson's disease who was treated with sodium diethyldithiocarbamate ("dithiocarb") during a period of five months are described. Intravenous administration of dithiocarb in daily dosages of 10 and 20 mg. per kg. of body weight resulted in clinical improvement and increased excretion of copper in the urine but did not reverse the pre-existing positive copper balance. Oral administration of dithiocarb in daily dosage of 30 mg. per kg. of body weight produced a threefold increase in the fecal excretion of copper and thereby resulted in negative copper balance. Measurements of nickel revealed that the patient maintained a positive nickel balance. Administration of dithiocarb intravenously in dosage of 20 mg. per kg. of body weight, or orally, in dosage of 30 mg. per kg., resulted in a negative metabolic balance for nickel. Treatment with dithiocarb was accompanied by a striking clinical response. The patient's neurologic involvement had been so severe that she had been unable to walk, to feed herself or to speak intelligibly. Following dithiocarb therapy she became able to speak clearly and to return to light housework. The Kayser-Fleischer corneal rings became less intense, and measurements of hepatic function returned to the normal ranges. more...