Multiple epigenetic changes, including alterations in DNA methylation occur during tumorigenesis. Various inhibitors of DNA methylation have been developed to prevent proliferation of cancer cells. 5-fluoro-2(')-deoxycytidine (FCdR) is one such DNA methylation inhibitor, which is currently in phase II clinical trial. To investigate the molecular mechanism/s by which FCdR might mediate repression of tumor cell proliferation, we analyzed the toxicity of FCdR in various cell lines established from different sarcomas. We found HCT116, a colon cancer cell line, is much more sensitive to FCdR compared to others. FCdR treatment inhibited HCT116 cells at G2/M check point and up-regulated expression of multiple cancer-related genes, which could be due to its inhibitory activity towards DNA methylation. Furthermore, we found that FCdR activates DNA damage response pathway. Using an inhibitor for ATM and ATR kinases activity, which are required for amplifying the DNA damage repair signal, we show that FCdR induced inhibition of HCT116 cells at G2/M is mediated through activation of DNA damage response pathway.
Electronic supplementary material: The online version of this article (doi:10.1186/2193-1801-1-65) contains supplementary material, which is available to authorized users.
Keywords: Cancer; Cell cycle; DNA damage response; DNA methylation; FCdR; p53.