The Effects Of PI3K/Akt Signaling Pathway On Apoptosis Induced By H₂O₂ In PC12 Cells

Objective To investigate the effects and mechanism of phosphatidylinositol3-kinase(PI3K) signaling pathway on apoptosis induced by hydrogen proxide (H₂O₂) in rat pheochromocytoma(PC12) cells.Methods In the present study, PC12 cells were preconditioned with 20μMLY294002(a PI3K-specific inhibitor) for 60 min, followed by exposures to different concentrations (20, 50, 100, 200, 400, 500μM) of H₂O₂ for 24-h respectively, cells growth inhibition rate was assessed by MTT. Using H₂O₂(200μM)-induced apoptosis model in PC12 cells, pretreatment with or without LY294002(20μM) for lh, apoptotic cell death was assessed by Hoechst33342/PI nuclei double staining, DNA ladder and flow cytometry. To further explore the downstream effector of PI3K activation, activation of CPP32, protein expression related with apoptotic regulation including Bcl-2, Bcl-X_L, Bad, and phosphorylation of Bad was examined by Western blotting.Results After pretreated with LY294002(20μM) for 1h, â‘  by MTT, cellgrowth inhibition rate H₂O₂-caused was increased markedly was examined; â‘¡ typically apoptotic nuclei and more stronger DNA ladder was observed, increased in the number of apoptotic cell death was examined. (3) elevated level of CPP32 activation was observed, with decrease in protein expression of Bcl-2, Bcl-X_L, and declined level in phosphorylation of Bad.Conclusions The results suggested, transient activation of PI3K prevents from apoptosis H₂O₂-induced in PC12 cells. PI3K signaling pathway delays the...