17β-雌二醇对子宫内膜癌细胞磷脂酰肌醇3激酶/蛋白激酶B信号传导通路的活化

目的:探讨17β雌二醇(E2)对子宫内膜癌细胞系HEC1A磷脂酰肌醇3激酶/蛋白激酶B(PI3K/PKB)信号传导通路的激活作用以及PI3K抑制剂和雌激素受体(ER)拮抗剂对它的影响。方法:应用免疫印迹杂交技术检测1×106mol/LE2作用于HEC1A细胞不同时间和不同浓度E2作用细胞15min后PKB的活化情况,同法检测PI3K抑制剂LY294002和ER拮抗剂ICI182780对E2活化PKB的影响。结果:1×106mol/LE2作用于HEC1A细胞15min时,PKB活化最明显,Ser473位点磷酸化PKB和总PKB比值(pPKB/PKB)为0.7877±0.0346,而基础值为0.5198±0.0166(P<0.001),且持续至少达2h,随着E2浓度的增加,PKB活化逐渐增强;随着LY294002作用浓度增加,E2作用HEC1A细胞后PKB的活化水平逐渐下降,浓度为50μmol/L时已完全阻断了E2对HEC1A细胞PKB的活化;而随着ICI182780浓度的增加,E2作用HEC1A细胞后PKB的活化水平无明显改变。结论:E2可通过非转录效应,迅速激活HEC1A细胞的PI3K/PKB信号传导通路,而且是ER非依赖性的。

Activation of phosphatidylinositol 3-kinase-protein kinase B(PI-3K-PKB)induced by 17β-estradiol in endometrial carcinoma cell

Objective:To study whether PI-3K/PKB signaling pathway can be activated rapidly by estradiol by non-nuclear action and also,whether PI-3K inhibitor,as well as ER antagonist,can inhibit such non-nuclear action of E_2 in HEC-1A.Methods:Levels of phosphorylated PKB(p-PKB)(Ser~473 site) and total PKB were examined by western blot in HEC-1A cell after stimulation with 10~-6mol/L E_2 for different times and with varied doses of E_2 for 15min.Inhibitory effect of LY294002 and ICI182 780 on activation of PKB induced by E_2 were also studied.p-PKB/PKB was used as levels of activation of PKB.Results:The maximal activation of PKB (maximal levels of p-PKB/PKB) took place at 15min (0.7877±0.0346,while 0min was 0.5198±0.0166,P<0.001)and its activation persisted at least 2 hours after stimulation with 10~-6mol/L E_2 in HEC-1A cell.With increased doses of E_2,the activation of PKB increased gradually;PI-3K inhibitor,LY294002,could inhibited the activation of PKB induced by E_2 in HEC-1A.Levels of PKB decreased gradually with increased concentrations of LY294002 and 50μmol/L LY294002 completely blocked the activation of PKB induced by E_2.However,ICI182 780 did not affect the activation of PKB induced by E_2.Conclusion: 17β-estradiol,by non-nuclear action,can activate promptly PI-3K-PKB signaling pathway in endometrial carcinoma cell line HEC-1A.This action of E_2 is ER-independent.