OBJECTIVETo investigate the effects of simvastatin on the proliferation, cell cycle and expression of cyclin-dependent kinase inhibitor p21 protein in human hepatocellular carcinoma (HepG2) cells in vitro.

METHODSHepG2 cells were administrated with simvastatin. Proliferation of the cells was detected by MTT assay, cell cycle was measured by flowcytometry and the cyclin-dependent kinase inhibitor p21 protein expression was detected by immunocytochemistry. The results were evaluated by factorial design and one-way analysis of variance.

RESULTSSimvastatin inhibited HepG2 cells growth in vitro (F(concentration) = 1264, P value less than 0.001; F(time) = 17.466, P value less than 0.001; F(concentration*time) = 35.053, P value less than 0.001) and could arrest HepG2 cells in G0/G1 phase of cell cycle. However, apoptosis of HepG2 cells was not obvious. Simvastatin could also increase cyclin-dependent kinase inhibitor p21 protein expression (F = 512.133, P value less than 0.001).

CONCLUSIONSimvastatin can inhibit the growth of HepG2 cells in vitro, which may be explained by its effects of enhancing cyclin-dependent kinase inhibitor p21 protein expression and arresting HepG2 cells at G0/G1 phase of cell cycle.