• Hydrogen peroxide;
  • Apoptosis;
  • Human gastric carcinoma cells


Hydrogen peroxide (H2O2), a representative ROS, has been used to study the apoptosis of cancer cells to oxidative stress. In this study, we exploited the cellular and molecular mechanisms involved in H2O2-induced apoptosis in human gastric carcinoma MGC803 cells. Exposure of cells to H2O2 might cause significant viability loss and the increase in apoptotic rate. Treatment with 0.4 mmol/L H2O2 up-regulated Bax but down-regulated Bcl-2 in a time-dependent manner, while Bcl-xL expression remained unchanged. Our results also showed that the levels of Fas and Fas-L were increased, the pro-caspase-3 and pro-caspase-9 were down-regulated in H2O2-treated MGC803 cells. Under H2O2 stress, we found that the protein p53 also participated in MGC803 cells apoptosis. Taken together, the present study indicated that Fas-mediated cell surface death receptor pathway and mitochondria-mediated pathway may participate in regulating the MGC803 cells apoptosis under oxidative stress.