miR-613 inhibits the growth and invasiveness of human hepatocellular carcinoma via targeting DCLK1.

microRNAs (miRNAs) play key regulatory roles in various biological processes. In this study, we aimed to determine the expression and biological roles of miR-613 in hepatocellular carcinoma (HCC). Compared with non-cancerous liver tissues, miR-613 was significantly downregulated in HCC tissues. Ectopic expression of miR-613 significantly suppressed the proliferation and invasion of Hep3B and SMMC-7721 HCC cells. Bioinformatic and luciferase reporter analysis identified doublecortin-like kinase 1 (DCLK1) as a direct target of miR-613. Overexpression of miR-613 inhibited the expression of DCLK1 in HCC cells. There was a significant inverse correlation between miR-613 and DCLK1 protein expression in HCC samples. Small interfering RNA-mediated silencing of DCLK1 phenocopied the suppressive effects of miR-613 in HCC cells. Rescue experiments demonstrated that co-transfection of DCLK1 lacking the 3'-untranslated region partially prevented miR-613-induced suppression of HCC cell proliferation and invasion. In vivo studies confirmed that miR-613 overexpression retarded the growth of Hep3B xenograft tumors in nude mice, coupled with a reduction in the percentage of Ki67-positive tumor cells and DCLK1 protein expression. In conclusion, we provide first evidence for the suppressive activity of miR-613 in HCC, which is causally linked to targeting of DCLK1. Restoration of miR-613 may provide a potential therapeutic strategy for HCC.