抑癌基因PTEN对乳腺癌ZR-75-1细胞增殖和转移的抑制作用

背景与目的:研究表明,抑癌基因PTEN不仅能抑制肿瘤细胞的增殖,还能抑制其转移,但其机理还不甚明了.本文研究抑癌基因PTEN对人乳腺癌ZR-75-1细胞增殖和转移的作用.方法:以脂质体介导法分别将野生型PTEN质粒和磷酸酶缺陷的PTEN质粒转染人乳腺癌ZR-75-1细胞,用MTT法测定细胞增殖抑制率:转染后用嘌呤霉素筛选阳性克隆.用Western blot法检测细胞中PTEN蛋白的表达.通过细胞-基质粘附实验和人工重组基底膜侵袭实验,检测细胞粘附抑制率与侵袭抑制率.结果:野生型PTEN质粒转染的ZR-75-1细胞增殖明显被抑制,并伴有部分细胞凋亡;该细胞与未经转染的和磷酸酶缺陷的PTEN质粒转染的ZR-75-1细胞比较.细胞增殖抑制率差异均有统计学意义(42.7% vs.0%及2.7%,P＜0.01),细胞增殖抑制效应随细胞培养时间与质粒浓度的增加而增强.而磷酸酶缺陷的PTEN质粒转染的与未经质粒转染的ZR-75-1细胞比较,细胞增殖抑制率差异无统计学意义(2.7%vs.0%,P＞0.05).在两种PTEN质粒转染的ZR-75-1细胞中PTEN蛋白均明显表达,其中转染野生型PTEN质粒的细胞的粘附抑制率与侵袭抑制率分别达65.7%和70.4%,而转染磷酸酶缺陷的PTEN质粒的ZR-75-1细胞的粘附抑制率与侵袭抑制率分别只有8.8%和6.9%(P＜0.05).结论:具有双特异磷酸酶活性的野生型PTEN基因对ZR-75-1细胞的增殖和转移有一定的抑制作用.

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.