Knockdown of FoxM1 by siRNA interference decreases cell proliferation, induces cell cycle arrest and inhibits cell invasion in MHCC-97H cells in vitro

Aim: To investigate the effects of small interfering RNA (siRNA) knockdown of forkhead box M1 (FoxM1) on the proliferation and invasion capacities of human hepatocellular carcinoma MHCC-97H cells in vitro. Methods: The expression levels of FoxM1 in human hepatocellular carcinoma samples, adjacent non-hepatocellular carcinoma liver samples and MHCC-97 cell lines were detected by RT-PCR and Western blotting. FoxM1 siRNA was transfected into MHCC-97H cells with Lipofectamine 2000. Cell growth was evaluated by 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and cell cycle analysis was performed by flow cytometry. Protein expression levels were evaluated by Western blotting. Anchorage-independent growth and the invasive potency of MHCC-97H cells were measured by soft agar colony formation and a transwell cell invasion assay, respectively. Results: FoxM1 was over-expressed in hepatocellular carcinoma samples compared to adjacent non-hepatocellular carcinoma liver samples. FoxM1 siRNA was successfully transfected into MHCC-97H cells, resulting in the significant inhibition of FoxM1 mRNA and protein expression. Down-regulation of FoxM1 inhibited cell proliferation, caused cell cycle arrest, and decreased invasion of MHCC-97H cells. Compared with control and mock groups, the FoxM1 siRNA transfected cells showed decreased protein expressions of cyclin B1 and cyclin D1, whereas p27 protein expression was increased. Down-regulation of FoxM1 reduced the expression of matrix metalloproteinase-2 (MMP-2) and urokinase plasminogen activator (uPA). Conclusion: FoxM1 is functionally involved in hepatocellular carcinoma cell proliferation and invasion and is a potential target for hepatocellular carcinoma therapy.