野生型PTEN基因高表达对膀胱移行细胞癌EJ细胞的抑癌作用

Overexpression of PTEN gene inhibits proliferation of bladder transitional carcinoma cell line EJ

目的 探讨外源性野生型人酪氨酸磷酸酶（PTEN）基因的高表达对膀胱移行细胞癌EJ细胞的抑癌作用。方法 利用携带人PTEN基因的野生型、磷酸酶域突变型质粒体外分别转染人膀胱移行细胞癌EJ细胞。Western blot检测目的基因PTEN的表达，观察细胞形态变化及超微结构变化；MTIO法检测细胞增殖率及转染细胞对吡柔比星（THP）和丝裂霉素（MMC）的敏感性；Western blot法检测bcl-2蛋白的表达。以空载质粒作为对照。结果 质粒转染后，EJ细胞的PTEN蛋白表达上升75．0％。转染野生型质粒后，EJ细胞异型性低，出现典型凋亡小体，细胞增殖率下降40．1％，bcl-2蛋白表达被下调，并提高了对THP和MMC的敏感性。而转染突变型质粒的EJ细胞则无此作用。结论 野生型PTEN基因在体外对膀胱移行细胞癌EJ细胞增殖有明显抑制作用，诱导细胞凋亡，磷酸酶域突变型PTEN基因无此作用。野生型PTEN的抑癌作用可能与其对bcl-2蛋白表达的下调有关。

Objective To evaluate the anticancer effects of exogenous human WT-PTEN overexpression on bladder transitional carcinoma cell line EJ. Methods The plasmid containing WT-PTEN or mutant PTEN was separately transfected into bladder transitional carcinoma cell line E J, and the protein expression of PTEN in the EJ cells was detected by Western blot. Cell morphological changes were observed under the inverted microscope and transmission electron microscope. MTF test was used to assess the effect of PTEN on proliferation and anticancer effects for mitomycin and theraubicin. The change of bcl-2 expression in the cells was measured by Western blot. The empty plasmid was used as control. Results Western blot analysis showed that EJ cells expressed high level of PTEN protein after transfection with WT-PTEN or mutant FrEN plasmid. Abnormal morphological changes of the cells were observed in WT-PTEN transfected groups. The growth of EJ cells treated with WT-PTEN was significantly inhibited by 40.1% and anticancer effects were enhanced by mitomycin and theraubicin, but the cells transfected with mutant PTEN plasmid did not show such similar biological behavior. Conclusion WT-PTEN gene transfection can suppress the in vitro growth and induce apoptosis of bladder transitional carcinoma cell line EJ cells. Mutant PTEN does not show similar biological behavior. Overexpression of WT-PTEN inhibits cancer cell proliferation by down-regulating bcl-2 expression in the cells.