MiR-181a overexpression induced cell proliferation in HCC cells. (A) SMMC-7721 cells were transfected with pTARGET-miR-181a, miR-181a inhibitor and their negative controls. 48 h after transfection, expression of miR-181a was measured by qRT-PCR. (B) Effect of miR-181a on cell proliferation was measured by MTS assay in pTARGET-miR-181a or miR-181a inhibitor transfected SMMC-7721 cells. (C) Relative miR-181a expression in p-miR-181a which can stably express miR-181a. miRNA abundance was normalized to U6 RNA. (D) Representative pictures of colony formation assay of p-miR-181a and p-control cells. Colonies were evaluated and values were reported as the ratio. *P < 0.05, **P<0.01.