Abstract: 【Abstract】　Objective　To investigate the effect of atorvastatin on the proliferation , cell cycle and COX-2 protein expression of human hepatocellular carcinoma (HepG2) cells in vitro.Methods　 The human hepatocellular carcinoma HepG2 cells were employed during logarithmic growth phase and atorvastatin were administrated and the final concentrations were 0, 0.1μM,1μM,10μM,100μM respectively. Proliferation of the cells was detected by cell counting and MTT assay ,cell cycle was measured by flowcytometry (FCM), COX-2 protein expression was detected by immunocytochemistry. Results　1 Atorvastatin suppressed growth of HepG2 cells in a dose- and time-dependent manner. There was no significant difference between 0.1μM group and 0μM group. 2.Cell cycle analysis revealed that atorvastatin caused a dose-dependent increase of cells in G0/G1 phase of the cell cycle. At the same time the cells in S and G2/M phase were decreased.However, apoptosis in HepG2 cells was not obvious. 3.Atorvastatin inhibited COX-2 protein expression in a dose-dependent manner. Conclusion　Atorvastatin inhibited HepG2 cells growth in vitro, which may be related with its inhibitory effect on COX-2 protein expression and arresting HepG2 cells at G0/G1 phase of cell cycle.

Key words: Atorvastatin, Cellcycle, hepatic cancer, COX-2