Next-Generation Sequencing Reveals the Role of Epigallocatechin-3-Gallate in Regulating Putative Novel and Known microRNAs Which Target the MAPK Pathway in Non-Small-Cell Lung Cancer A549 Cells

Lung cancer constitutes 85% of non-small cell lung cancer diagnosed cases. MicroRNAs are novel biomarkers that are capable of modulating multiple oncogenic pathways. Epigallocatechin-3-gallate (EGCG) is a potent chemopreventive and chemotherapeutic agent for cancer. We aimed to identify important known and putative novel microRNAs modulated by EGCG in A549 cells using next-generation sequencing and identify their gene targets. Preliminary analysis revealed an IC50 value of 309 μM with G0/G1 phase arrest at 40 μM EGCG treatment. MicroRNA profiling identified 115 known and 4 putative novel microRNAs in 40 μM and 134 known and 3 putative novel microRNAs in 100 μM EGCG-treated A549 cells. The top 10 up-expressed microRNAs were similar between the untreated control and EGCG-treated A549 cells. An up-expression in oncogenic microRNAs, which belong to broadly conserved seed families, were observed in untreated control and EGCG-treated A549 cells. Kyoto Encyclopedia of Genes and Genomes and Protein Analysis Through Evolutionary Relationships pathway analyses of the validated microRNA targeting genes strengthened the hypothesis that EGCG treatment can modulate microRNAs that play a significant role in the MAPK signaling pathway. Expression profile of microRNAs was validation by quantitative real time PCR of randomly selected microRNAs. This study identified signature microRNAs that can be used as novel biomarkers for lung cancer diagnosis.