PTEN基因诱导人胚肾293细胞凋亡和细胞周期停滞

The Expression of PTEN in HEK293 Cells Induces Apoptosis and Cell Cycle Arrest

为了研究抑癌基因PTEN过表达对HEK2 93细胞凋亡和细胞周期停滞的作用 ,以野生型PTEN和PTEN突变子 (T910G)表达质粒分别转染无PTEN表达的人胚肾 2 93细胞 ,采用细胞质梯度DNA方法检测细胞凋亡 ,以流式细胞仪分析细胞周期 .发现PTEN过表达能够诱导人胚肾 2 93细胞质中出现梯度DNA ,2 93细胞发生凋亡 ,PTEN过表达改变细胞周期分布 ,G0 /G1期细胞增加 13% ,S期细胞下降 15 % .PTEN突变子对细胞凋亡和G1细胞停滞的影响略弱于野生型PTEN .PTEN基因过表达明显下调血小板衍生生长因子 (PDGF)诱导的蛋白激酶B (PKB)和p4 2 ,p4 4 促分裂原活化蛋白激酶 (MAPK)磷酸化水平 ,PTEN突变子对p4 2 ,p4 4 MAPK磷酸化水平的调节作用略弱于野生型PTEN .PTEN通过抑制细胞增殖 。

It was to study whether overexpression of the tumor suppressor PTEN in HEK293 cells could lead to apoptosis and cell cycle arrest. The wild-type and mutant T910G of PTEN expression plasmids were constructed and transfected into PTEN-null HEK293 cells respectively. Apoptosis was evaluated by the appearance of cytosolic low molecular DNA ladder on the gel. Cell cycle was determined by flow-cytometric analysis. The Western blot analysis was performed to determine the phosphorylation levels of PKB/Akt and MAPK. The present data showed that the overexpression of PTEN in HEK293 cells could induce apoptosis and resulted in an increase in G1 cell population through inhibiting PKB/Akt and MAPK phosphrylation stimulated by PDGF. Mutant PTEN cause less apoptosis and G1 arrest than wild-type PTEN. MAPK dephosphorylation caused by mutant PTEN was not so significant as by wild-type PTEN. These data suggested that PTEN may exert its tumor-suppressive effects through both the inhibition of cell cycle progression and the induction of apoptosis.