PI3K Inhibition Sensitize the Cisplatin-resistant Human Ovarian Cancer Cell OVCAR3 by Induction of Oxidative Stress

Background:This study evaluates the effect of simultaneous AKT inhibition and cisplatin therapy in changes of Reactive Oxygen Species (ROS) production, apoptosis induction, and cell survival in cisplatin-resistant OVCAR3 cell.Methods:OVCAR3 cancer cells were treated with cisplatin, Ly 294002 (LY), and cisplatin+Ly to investigate the cytotoxicity effect of the mentioned groups via MTT assay. Then, DCFH-DA (2′, 7′-dichlorodihydro fluorescein diacetate) assay kit is used to assess the potential of treated groups in intracellular ROS generation. Protein expression levels of caspase-3, cleaved caspase 3, PI3K, Akt, p-Akt, XIAP, and Survivin are estimated through immunoblotting assay in all three experimental groups.Results:The results showed that all three treated groups, including cisplatin and Ly alone and co-administration of cisplatin+Ly, could reduce the cell vitality of OVCAR3 cancer cells, induced intracellular production of ROS and increased the expression level of activated caspase 3 and Akt protein, whereas down-regulated the phosphorylation of Akt protein. However, the effect of combination therapy was more tangible compared to single therapy and control groups. In contrast, the expression amount of XIAP, Survivin, and PI3K did not show detectable changes in comparison with the control group.Conclusion:The results showed that the AKT inhibition by Ly could sensitize the OVCAR3 cancer cells to the cisplatin and lower the effective dose of cisplatin through hyperactivation of oxidative stress.Key Words: Caspase-3, Cisplatin, Ovarian cancer, PI3K/Akt signaling