Objective: To explore the role of transfected pIRES-p21(waf1)-p27(kip1) gene on the centrosome duplication and cell proliferation of MCF-7, a breast cancer cell line.
Methods: The pIRES-p21(waf1), pIRES-p27(kip1) and pIRES-p21(waf1)-p27(kip1) genes were transfected into the MCF-7 cells by lipofection. The effect on proliferation was evaluated by MTT assay and cell growth curve was drawn. The cell cycle was analyzed by flow cytometry. The centrosome duplication was detected by using indirect immunofluorescence microscopy.
Results: After transfected 24 hours, the p21(waf1) and p27(kip1) protein expressions were significantly increased as compared with untransfected MCF-7 cells (P < 0.01), and cell growth was obviously inhibited and resulted in an accumulation of cells in G(1) (P < 0.01), presenting that the proportion of cells in G(1) phase was obviously increased from(47.28 +/- 2.25)% to (69.52 +/- 3.21)% of p21(waf1) transfected cells, (60.83 +/- 3.02)% of p27(kip1) transfected cells, and (78.37 +/- 2.83)% of p21 (waf1)-p27(kip1) transfected cells. The proportion of cells which contained unnormal centrosomes was obviously decreased, from (13.47 +/- 0.33)% to (5.07 +/- 0.38)%, (6.28 +/- 0.35)%, (3.47 +/- 0.23)%, respectively.
Conclusion: The transfer of p21(waf1) and p27(kip1) genes could inhibit the growth of human breast carcinoma cells and the unnormal duplication of centrosomes. p21(waf1) had a really synergy with p27(kip1) in these effects, suggesting p21(waf1)-p27(kip1) combined gene can inhibit the genesis and development of breast cancer and might have potential clinical significance as therapeutic agents of breast cancer.