Targeted inhibition of genome-wide DNA methylation analysis in epigenetically modulated phenotypes in lung cancer.

Abstract

DNA methylation analysis, an epigenetic specification, has been explored for partial determination of cancer cell phenotypes. The development of metastasis in cancerogenesis has led its feasible association with the epigenetic modulations. We generated highly aggressive non-small cell lung cancer cell lines (HTB56 and A549) by using in vivo selection approach. These were, then, subjected to DNA methylation analysis (genome-wide). We also explored the therapeutic effects of azacytidine, an epigenetic agent, on DNA methylation patterns as well as the in vivo phenotypes. During the development of highly aggressive cell lines, we observed widespread modulations in DNA methylation. Reduced representation bisulfite sequencing was used and compared with the less aggressive parental cell lines to identify the differential methylation, which was achieved up to 2.7 % of CpG-rich region. Azacytidine inhibited DNA methyltransferase and reversed the prometastatic phenotype. We found its high association with the preferential loss of DNA methylation from hypermethylated sites. After persisted exposure of azacytidine, we observed that DNA methylation affected the polycomb-binding sites. We found close association of DNA methylome modifications with metastatic capability of non-small cell lung cancer. We also concluded that epigenetic modulation could be used as a potential therapeutic approach to prevent metastasis formation as prometastatic phenotype was reversed due to inhibition of DNA methyltransferase.