Analysis of miRNA profile in Ago2-IP fraction after miR-195 or miR-497 overexpression

To explore functionally crucial tumor-suppressive (TS)-miRNAs in hepatocellular carcinoma (HCC), we performed integrative function- and expression-based screenings of TS-miRNAs in six HCC cell lines. The screenings identified seven miRNAs, which showed growth-suppressive activities through the overexpression of each miRNA and were endogenously downregulated in HCC cell lines. Further expression analyses using a large panel of HCC cell lines and primary tumors demonstrated four miRNAs, miR-101, -195, -378 and -497, as candidate TS-miRNAs frequently silenced in HCCs. Among them, two clustered miRNAs miR-195 and miR-497 showed significant growth-suppressive activity with induction of G1 arrest. Comprehensive exploration of their targets using Argonute2-immunoprecipitation-deep-sequencing (Ago2-IP-seq) and genome-wide expression profiling after their overexpression, successfully identified a set of cell-cycle regulators, including CCNE1, CDC25A, CCND3, CDK4, and BTRC. Our results suggest the molecular pathway regulating cell cycle progression to be integrally altered by downregulation of miR-195 and miR-497 expression, leading to aberrant cell proliferation in hepatocarcinogenesis. Analysis of miRNA profile change in the Ago2-IP fraction after overexpression with miR-195 or miR-497 miRNA expression analysis using Immunopreticipated RNA fractions with anti-human-Argonute 2 antibody for non-treated, miR-195 or miR-497 overexpressed Hep G2 cell.