[Pro-apoptotic effects of luteolin on hepatoma HepG2 cells].

OBJECTIVE: To investigate the effect of luteolin on cell growth and apoptosis of HepG2 cells in vitro. METHODS: Cultured HepG2,HL60,A549 and LO2 cells were treated with luteolin for different doses (0 µg/ml,2.5 µg/ml,10 µg/ml and 20 µg/ml) and varied times (0 h,24 h,48 h and 72 h). Cell viability was measured with MTT assay and IC50 was calculated. The reactive oxygen species (ROS) levels in HepG2 cells treated with luteolin for 6 h and 12 h were measured with flow cytometry. Cell apoptosis of HepG2 cells treated with luteolin for 24h was examined with flow cytometry and Annexin V-FITC/PI. Expression levels of apoptosis pathway proteins (p53,ASPP2 and iASPP) in HepG2 cells were detected with western blot and the dose and time-effect was analyzed. RESULTS: Luteolin effectively inhibited tumor cell proliferation in a dose-and time-dependent manner,and the inhibition rates of 20 µg/ml Luteolin for 72 h were 39.34%,62.90%,57.57% and 62.90% to LO2,HepG2, HL60 and A549 cells,respectively. The intracellular ROS level was decreased in HepG2 cells by 13.88% and 41.11% after being treated with luteolin for 6 h and 12 h,respectively. The apoptosis rate of HepG2 cells treated with luteolin for 24 h was 14.43%,and western blot showed that luteolin reduced the expression level of iASPP by 77.07% and up-regulated the expression of p53 by 179.37% and ASPP2 by 725.02% in HepG2 cells treated with luteolin for 12 h. CONCLUSION: Luteolin has ant-proliferative and pro-apoptotic activity on hepatoma HepG2 cells, which is associated with the altered expression of pro-apoptotic factors and decreased ROS level in HepG2 cells.