Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China (C.T., X.P., Z.G., R.G., L.L., X.C.) and University of Chinese Academy of Sciences, Beijing, China (C.T., R.G., L.L., X.C.).
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R. China (C.T., X.P., Z.G., R.G., L.L., X.C.) and University of Chinese Academy of Sciences, Beijing, China (C.T., R.G., L.L., X.C.)
Drug Metab Dispos. 2021 Jun;49(6):434-441. doi: 10.1124/dmd.120.000317. Epub 2021 Mar 24.
Disulfiram, an antialcoholism drug, could potentially be repurposed as an anticancer drug because of the formation of copper(II) diethyldithiocarbamate (CuET) from dithiocarb (DTC, a reduced metabolite of disulfiram) and Cu CuET exhibited preferential distribution to tumor tissues. This study investigated the mechanism of CuET accumulation in tumor tissues by employing MDA-MB-231 human breast cancer cells. The concentration of CuET in cells treated with DTC and Cu in acidic culture medium (pH 6.8) was significantly higher than that of the control group (pH 7.4). Subsequently, the effects of pH on the uptake of DTC, Cu, and CuET were investigated separately. The acidic environment significantly increased the uptake rate of DTC and Cu but had no effect on CuET. MDA-MB-231 cells overexpressing copper transporter hCTR1 were constructed to evaluate its intermediate role in CuET accumulation. After treatment with CuCl followed by DTC for 15 minutes, the levels of CuET and Cu in hCTR1-overexpressed cells were 2.5 times as much as those of vector group. In the tumors of cancer xenograft models constructed by hCTR1-MDA-MB-231 cells, the concentrations of CuET and Cu were also significantly higher than those of control group. In conclusion, the acidic microenvironment of tumors can promote the enrichment of CuET in tumors through dual action. On the one hand, it can promote transmembrane transport of DTC by converting ionic DTC into molecular state. On the other hand, it enhances Cu uptake by activating hCTR1, which ultimately leads to the enrichment of CuET. SIGNIFICANCE STATEMENT: Increasing evidence suggests that the antitumor activity of disulfiram is related to the formation of a copper(II) diethyldithiocarbamate (CuET) of its reducing metabolite dithiocarb with copper(II) ion, which is preferentially distributed in tumor tissues. We showed that the acidic microenvironment, a common feature of many solid tumor tissues, could promote intracellular CuET accumulation through dual action without changing CuET uptake. This result is helpful for the formulation of clinical dosage regimens of disulfiram in cancer treatment.
双硫仑，一种戒酒药物，由于双硫仑（Disulfiram）的还原代谢物二硫代氨基甲酸盐（DTC）与铜（Cu）形成铜（II）二乙基二硫代氨基甲酸盐（CuET），因此有可能被重新用作抗癌药物。CuET 优先分布在肿瘤组织中。本研究通过 MDA-MB-231 人乳腺癌细胞探讨了 CuET 在肿瘤组织中积累的机制。用 DTC 和 Cu 在酸性培养介质（pH6.8）处理的细胞中 CuET 的浓度明显高于对照组（pH7.4）。随后，分别研究了 pH 对 DTC、Cu 和 CuET 摄取的影响。酸性环境显著增加了 DTC 和 Cu 的摄取率，但对 CuET 没有影响。构建了过度表达铜转运蛋白 hCTR1 的 MDA-MB-231 细胞，以评估其在 CuET 积累中的中间作用。用 CuCl 处理后再用 DTC 处理 15 分钟，hCTR1 过表达细胞中 CuET 和 Cu 的水平是对照组的 2.5 倍。在 hCTR1-MDA-MB-231 细胞构建的癌症异种移植模型的肿瘤中，CuET 和 Cu 的浓度也明显高于对照组。总之，肿瘤的酸性微环境可以通过双重作用促进 CuET 在肿瘤中的富集。一方面，它可以通过将离子型 DTC 转化为分子态来促进 DTC 的跨膜转运。另一方面，它通过激活 hCTR1 增强 Cu 的摄取，最终导致 CuET 的富集。意义陈述：越来越多的证据表明，双硫仑的抗肿瘤活性与其还原代谢物二硫代氨基甲酸盐与铜（II）离子形成的铜（II）二乙基二硫代氨基甲酸盐（CuET）有关，该化合物优先分布在肿瘤组织中。我们表明，酸性微环境，许多实体瘤组织的共同特征，可以通过双重作用促进细胞内 CuET 的积累，而不改变 CuET 的摄取。这一结果有助于制定癌症治疗中双硫仑的临床剂量方案。
