PTEN在HepG2细胞中诱导凋亡发生及上调p53表达  

PTEN induces apoptosis and up-regulates p53 expression in HepG2 cells

作　　者：杨志芳[1] 易继林[1] 李兴睿[1] 谢大兴[1] 廖晓锋[1] 马昕[2] 

机构地区：[1]华中科技大学同济医学院附属同济医院普外科,武汉430030 [2]华中科技大学同济医学院附属同济医院肝病研究所,武汉430030

出　　处：《中华肝脏病杂志》2004年第12期745-748,共4页Chinese Journal of Hepatology

摘　　要：目的 研究肿瘤抑制基因PTEN对HepG2细胞凋亡及p53蛋白表达的影响,并探讨相关机制。方法 将携带有野生型PTEN基因及突变型G129E-PTEN,C124A-PTEN基因的真核表达载体转染HepG2细胞,利用western印迹杂交检测PTEN表达、蛋白激酶B(PKB/Akt)和焦点粘附激酶(FAK)的磷酸化状态,以及野生型p53蛋白表达水平的变化,并应用流式细胞仪,激光共聚焦技术检测细胞周期及细胞凋亡情况。结果 与对照细胞相比,转染野生型PTEN和G129E-PTEN的HepG2细胞中磷酸化FAK(-65％,-65％)与磷酸化Akt(-93％,-35％)表达均存在不同程度的下调,而细胞凋亡率分别增加至19.8％±1.2％和9.2％±0.6％,并且p53蛋白表达上调(+120%,,+50％);然而转染C124A-PTEN的细胞中各项检测指标均无明显变化。 结论 PTEN依赖其蛋白磷酸酶活性抑制FAK的磷酸化;并主要通过脂质磷酸酶活性抑制Akt的磷酸化,并诱导HepG2细胞凋亡和p53蛋白表达上调。Objective To investigate the effects of tumor suppressor gene PTEN on apoptosis and protein expression of p53 in HepG2 cells, as well as to explore its mechanisms. Methods HepG2 cells were transfected with GFP plasmids containing wild-type PTEN or G129E-PTEN and C124A-PTEN in vitro. Both the expression of wild-type p53 and the phosphorylation of protein kinase B (PKB/Akt) and focal adhesion kinase (FAK) were detected by Western blotting. Flow cytometry and confocal microscopy were used to analyze apoptosis of the transfected cells. Results Compared with the control, the expression of phosphorylated FAK and phosphoylated Akt were down-regulated in HepG2 cells transfected with wild-type PTEN (-65%, -93%) and G129E-PTEN (-65%, -35%), whereas the apoptosis percentage increased to (19.8±1.2)% and (9.2±0.6)%, and p53 expression was up-regulated by 120% and 50%, respectively. However, in the cells transfected with C124A-PTEN, neither the phosphorylation of FAK and Akt nor the apoptosis percentage and p53 expression had changed. Conclusion PTEN can dephosphrylate FAK through its protein phosphatase activity, and suppress phosphorylation of Akt mainly through its lipid phosphatase activity. Consequently, it can induce apoptosis of HepG2 cells and up-regulate p53 expression.

关 键 词：HEPG2细胞 PTEN 磷酸化 P53蛋白表达 FAK 上调 转染 蛋白激酶B 激光共聚焦 基因 

分 类 号：R363[医药卫生—病理学]