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
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- 作者：Vikas Sharma ; Vikas Verma ; Nand Lal ; Santosh K. Yadav ; Saumya Sarkar ; Dhanaraju Mandalapu ; Konica Porwal ; Tara Rawat ; J.P. Maikhuri ; Singh Rajender ; V.L. Sharma and Gopal Gupta
- 刊名：Molecular Carcinogenesis
- 出版年：2016
- 出版时间：November 2016
- 年：2016
- 卷：55
- 期：11
- 页码：1843-1857
- 全文大小：4550K
- ISSN：1098-2744
文摘
Estrogen Receptor-β (ER-β), a tumor-suppressor in prostate cancer, is epigenetically repressed by hypermethylation of its promoter. DNA-methyltransferases (DNMTs), which catalyze the transfer of methyl-groups to CpG islands of gene promoters, are overactive in cancers and can be inhibited by DNMT-inhibitors to re-express the tumor suppressors. The FDA-approved nucleoside DNMT-inhibitors like 5-Azacytidine and 5-Aza-deoxycytidine carry notable concerns due to their off-target toxicity, therefore non-nucleoside DNMT inhibitors are desirable for prolonged epigenetic therapy. Disulfiram (DSF), an antabuse drug, inhibits DNMT and prevents proliferation of cells in prostate and other cancers, plausibly through the re-expression of tumor suppressors like ER-β. To increase the DNMT-inhibitory activity of DSF, its chemical scaffold was optimized and compound-339 was discovered as a doubly potent DSF-derivative with similar off-target toxicity. It potently and selectively inhibited cell proliferation of prostate cancer (PC3/DU145) cells in comparison to normal (non-cancer) cells by promoting cell-cycle arrest and apoptosis, accompanied with inhibition of total DNMT activity, and re-expression of ER-β (mRNA/protein). Bisulfite-sequencing of ER-β promoter revealed that compound-339 demethylated CpG sites more efficaciously than DSF, restoring near-normal methylation status of ER-β promoter. Compound-339 docked on to the MTase domain of DNMT1 with half the energy of DSF. In xenograft mice-model, the tumor volume regressed by 24% and 50% after treatment with DSF and compound-339, respectively, with increase in ER-β expression. Apparently both compounds inhibit prostate cancer cell proliferation by re-expressing the epigenetically repressed tumor-suppressor ER-β through inhibition of DNMT activity. Compound-339 presents a new lead for further study as an anti-prostate cancer agent.