Influence of arsenic trioxide on apoptosis and Bcl-2/Bax expression of hepatoma cell line HepG2

Objective To investigate the apoptosis inducing activity of arsenic trioxide in hepatoma cell line HepG2 and its mechanisms.Methods HepG2 cells were treated with arsenic trioxide at 1.25,2.5,5,10,20μmol/L.Cell growth inhibitory rate was detected by MTT colorimetric assay every 24 hours.Apoptosis rate was analyzed by Annexin V/PI fluorescence staining and TUNEL.Changes in expression of Bcl-2 and Bax protein were assayed by flow cytometry.Results MTT tests showed HepG2 cell proliferation was significantly inhibited by arsenic trioxide in time and dosedependent fashion.Marked apoptosis was detected by Annexin V/PI and TUNEL in HepG2 cells after treatment by arsenic trioxide at 5,10,20μmol/L after 24 hours and increased in a dose-dependent manner(t=-2.96,-4.15,-7.33,P 0.05).The Bcl-2 expression decreased and the Bax expression increased in HepG2 cells induced by arsenic trioxide after 24 hours (t=3.59,5.65,6.94,7.62,7.92,P0.05).Conclusions Bcl-2 and Bax protein probably correlated with the activation of apoptosis in HepG2 cells induced by arsenic trioxide.