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

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.

Crizotinib-loaded polymeric nanoparticles in lung cancer chemotherapy.

The study describes the development of polylactide-tocopheryl polyethylene glycol 1000 succinate (PLA-TPGS)-based nanosystem as a carrier of crizotinib (CZT) to achieve superior anticancer efficacy in lung cancer therapy. We have demonstrated that block copolymer and hydrophobic drug is capable of self-assembling into a very stable nanocarrier, with suitable properties that allow their application for cancer drug delivery. Drug release study showed a sustained release pattern as a result of entrapment in the hydrophobic core of micelles. CZT/PT NP showed a noticeable cytotoxic effect in NCIH3122 lung cancer cells in a dose-dependent manner. Furthermore, morphological imaging and Live/Dead assay revealed a superior anticancer efficacy for nanoformulations. The polymeric nanoparticle showed a predominant presence in the cytoplasmic region of cell, indicating a typical endocytosis-mediated cellular uptake. The annexin V/PI staining-based apoptosis assay showed a remarkable ~40 % apoptosis (early and late apoptosis cells) comparing to only ~25 % apoptosis by free CZT. Taken together, Vitamin E TPGS-modified PLA nanoparticles would be a potential drug delivery system to increase the chemotherapeutic efficacy of CZT in lung cancer chemotherapy.