To Study The Effect Of Megestrol Acetate Alone Or In Combination With NVP-BEZ235on PI3K/Akt Signal Pathway In Endometrial Cancer Cell Lines

Purpose:To investigate the therapeutic mechanism of megestrol acetate(MA) on endometrial cancer by studying the Akt portein changing after using progestin on endometrial Ishikawa cells and progestin-resistance Ishikawa cells. To investigate the influence of PI3K/mTOR pathway inhibitor (NVP-BEZ235) on inhibiting effect or resistance of progestin on endometrial cancer, by studying the cell proliferation of endometrial Ishikawa and progestin-resistance Ishikawa cells after using progestin alone or combination with NVP-BEZ235.Methods:Levels of phosphorylated Akt and total Akt were examined by Western Blotting in Ishikawa cells and progestin-resistance Ishikawa cells after being stimulated by MA alone, or MA combined with NVP-BEZ235.The effects of MA and NVP-BEZ235on cell proliferation, cell cycle and apoptosis were assessed in both cell lines by MTT assay, CCK-8assay and FACS analysis.Results:MA blocked the activation of Akt (pAkt/Akt) in Ishikawa cells. Levels of p-Akt/Akt decreased by25.90%,47.02%,53.89%,55.02%and85.48%(in comparison with control, P<0.05) after being stimulated by MA for15min,30min,1h,2h and24h respectively.The activation of Akt (p-Akt/Akt) increased by67.77%,9.60%,252.85%,514.99%, and604.14%(in comparison with control, P<0.05) after being stimulated by MA for15min,30min,1h,2h and24h in progestin-resistance Ishikawa cells.The levels of Akt(p-Akt/Akt) were inhibited by83.39%,85.25%,85.94%,0.33%and87.80%(in comparison with control, P<0.05) after being stimulated by MA and NVP-BEZ235for2h,6h,12h,24h and48h in Ishikawa cells, and93.20%,88.17%,85.84%,67.02%and73.75%(in comparison with control, P<0.05) in progestin-resistance Ishikawa cells.NVP-BEZ235significantly decreased cell proliferation in Ishikawa cells and progestin-resistance Ishikawa cells and the inhibitory effect was dependent on drug concentration and stimulating duration. Dose-dependent growth suppression was more drastically induced by MA combined with NVP-BEZ235than MA alone in both cell lines(P<0.05). Short-term action of NVP-BEZ235increased the sensitivity to MA in Ishikawa cells.The combination of NVP-BEZ235with MA affected the cell cycle distribution in Ishikawa cells significantly. The combination of NVP-BEZ235with MA promoted the apoptosis of Ishikawa cells and progestin-resistance Ishikawa cells.Conclusions:Progesterone can suppress PI3K/Akt signal pathway in Ishikawa cells and activate the signal pathway in progestin-resistance Ishikawa cells. MA combined with NVP-BEZ235blocked the activation of Akt effectively in Ishikawa cells and NVP-BEZ235blocked the activation of Akt induced by MA in progestin-resistance Ishikawa cells. NVP-BEZ235may promote the suppressive effect of MA on Ishikawa cells and reverse the resistance to MA in progestin-resistance Ishikawa cells.