Targeting ALDH2 with disulfiram/copper reverses the resistance of cancer cells to microtubule inhibitors.

Disulfiram (DSF) in combination with copper (Cu) has been reported to override drug resistance in cancer cells, and DSF combined with chemotherapy based on the microtubule inhibitor vinorelbine appears to prolong survival in non-small cell lung cancer patients. Here, we investigated the mechanisms underlying these findings. DSF/Cu reversed the microtubule inhibitor resistance in A549/Taxol and KB/VCR cells in vitro, and had anti-tumor effects in A549/Taxol and KB/VCR xenograft mice. DSF/Cu and DSF reduced the cancer stem cell (CSC) characteristics of drug-resistant A549/Taxol and KB/VCR cells, including sphere formation, colony generation and migration, and DSF/Cu was more effective than DSF alone. DSF/Cu also decreased the aldehyde dehydrogenase (ALDH) activity and the expression of P-gp and stem cell transcription factors in A549/Taxol and KB/VCR cells. Knockdown of ALDH2 attenuated the CSC characteristics of resistant cancer cells and enhanced their sensitivity to Taxol or VCR. Importantly, DSF/Cu treatment inhibited the expression of ALDH2 in vitro and in vivo. Our findings suggest that DSF/Cu reverses microtubule inhibitor resistance in cancer cells by suppressing ALDH2 expression, and Cu improves the activity of DSF.

Disulfiram combined with copper inhibits metastasis and epithelial-mesenchymal transition in hepatocellular carcinoma through the NF-κB and TGF-ß pathways.

Late-stage hepatocellular carcinoma (HCC) usually has a low survival rate because of the high risk of metastases and the lack of an effective cure. Disulfiram (DSF) has copper (Cu)-dependent anticancer properties in vitro and in vivo. The present work aims to explore the anti-metastasis effects and molecular mechanisms of DSF/Cu on HCC cells both in vitro and in vivo. The results showed that DSF inhibited the proliferation, migration and invasion of HCC cells. Cu improved the anti-metastatic activity of DSF, while Cu alone had no effect. Furthermore, DSF/Cu inhibited both NF-κB and TGF-ß signalling, including the nuclear translocation of NF-κB subunits and the expression of Smad4, leading to down-regulation of Snail and Slug, which contributed to phenotype epithelial-mesenchymal transition (EMT). Finally, DSF/Cu inhibited the lung metastasis of Hep3B cells not only in a subcutaneous tumour model but also in an orthotopic liver metastasis assay. These results indicated that DSF/Cu suppressed the metastasis and EMT of hepatic carcinoma through NF-κB and TGF-ß signalling. Our study indicates the potential of DSF/Cu for therapeutic use.