[Inhibitory effects of tumor suppressor gene PTEN on proliferation and metastasis of breast cancer ZR-75-1 cells].

Background & Objective: Tumor suppressor gene PTEN could not only inhibit the proliferation of cancer cells, but also inhibit their metastasis. However, the mechanism is still unclear. This study was to investigate the effects of PTEN gene on the proliferation and metastasis of human breast cancer ZR-75-1 cells, and explore the mechanisms.
Methods: Wild-type PTEN (wt-PTEN) plasmid and phosphatase-defective PTEN (G129R-PTEN) plasmid were transfected into ZR-75-1 cells by liposome, respectively. Cell proliferation was detected by MTT assay. Transfected cells were selected by puromycin. The expression of PTEN protein was detected by Western blot. Cell adhesion and invasion were tested by adhesion test and invasion test.
Results: The proliferation inhibition rate was significantly higher in wt-PTEN-transfected ZR-75-1 cells than in untransfected cells and G129R-PTEN-transfected cells (42.7% vs. 0% and 2.7%, P<0.01); there was no significant difference between untransfected cells and G129R-PTEN-transfected cells(P>0.05). The proliferation inhibition of ZR-75-1 cells was enhanced along with the increase of culture time and concentration of wt-PTEN. wt-PTEN also induced cell apoptosis. PTEN protein was expressed efficiently in the cells transfected with either wt-PTEN or G129R-PTEN. The inhibition rates of adhesion and invasion were significantly higher in wt-PTEN-transfected cells than in G129R-PTEN-transfected cells (65.7% vs. 8.8%, 70.4% vs. 6.9%, P<0.01).
Conclusion: Wild-type PTEN gene with dual-specific phosphatase activity can inhibit the proliferation and metastasis of ZR-75-1 cells.