Downregulation of microRNA-143 promotes cell proliferation by regulating PKCε in hepatocellular carcinoma cells

The abnormal expression of microRNAs (miRNAs) has been reported in hepatocellular carcinoma (HCC), however, the functional role of miR-143 in HCC remains to be fully elucidated. The present study aimed to investigate the effects of the downregulation of miR-143 on HCC cell proliferation and apoptosis, and elucidated the underlying mechanism. Hepg2 and Hep3B human hepatoma cell lines cells were transfected with miR-143 inhibitor. Following transfection, the cell viability and apoptosis were respectively determined using a 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide assay and flow cytometry, and the mRNA and protein levels of protein kinase C epsilon (PKC epsilon) were examined. The expression levels of PKCe were downregulated by short hairpin (sh) RNA, and the effects of the downregulation of miR-143 on HCC cell proliferation were measured. The results showed that the miR-143 inhibitor significantly promoted cell proliferation and suppressed apoptosis in the Hepg2 and Hep3B cells. The miR-143 inhibitor significantly increased the protein levels of PKCe in the Hepg2 and Hep3B cells; however, no significant differences were found in the mRNA levels of PKCe. In addition, the downregulation of PKCe markedly decreased the cell viability of the Hepg2 and Hep3B cells, and co-transfection with the miR-143 inhibitor and PKCe shRNA significantly alleviated the miR-143 inhibitor-induced high cell proliferation. Taken together, these results suggested that miR-143 acts as a tumor suppressor gene in HCC. The downregulation of mi-143 promoted cell proliferation by regulating PKCe in the HCC cells.