抑癌基因PTEN依赖其磷酸活性诱导人膀胱癌细胞BIU-87失巢凋亡机制

摘要

Objective: To investigate the effects and mechanisms of tumor suppressor gene PTEN on the induction of anoikis of human bladder transitional carcinoma cells BIU-87. Methods: BIU-87 cells were transfected with GFP plasmids containing wild-type PTEN or phosphatase inactivating mutant PTEN (C124A-PTEN) in vitro. The PTEN expression and the phosphorylation levels of focal adhesion kinase (FAK) and protein kinase B (PKB/Akt) were detected by Western blotting. Flow cytometry assay and laser scanning confocal microscopy were used to analyze apoptosis in adherent and non-adherent cells. Results:Compared with the control group, PTEN expression in the cells transfected with wild-type PTEN increased to 210%-260%,while the phosphorylation level of FAK and Akt decreased 59% ( P ＜ 0.01) and 89% ( P ＜ 0.01), respectively. And the anoikis percentage increased from 8.32 ± 0.57% to 37.62 ± 2.12%. In the cells transfected with C124A-PTEN, neither the phosphorylation of FAK and Akt nor the anoikis percentage had obviously changed, although the PTEN expression enhanced remarkably in comparison with the control. Conclusion: Through its phosphatase activity, tumor suppressor gene PTEN can suppress the phosphorylation of FAK and Akt, and induce anoikis in human bladder transitional carcinoma cells BIU-87.