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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。
BACKGROUND AND PURPOSE: Studies have shown that the tumor suppressor gene PTEN can not only inhibit the proliferation of tumor cells, but also inhibit its metastasis, but the mechanism is still unclear. This article studies the role of tumor suppressor gene PTEN on proliferation and metastasis of human breast cancer ZR-75-1 cells. METHODS: Wild type PTEN plasmid and phosphatase-deficient PTEN plasmid were transfected into human breast cancer cell line ZR-75-1 respectively by liposome-mediated method. The inhibition rate of cell proliferation was determined by MTT assay. After transfected with puromycin Positive clones were screened. Western blot was used to detect the expression of PTEN protein. Cell adhesion inhibition and invasion inhibition were measured by cell-matrix adhesion assay and artificial recombinant basement membrane invasion assay. Results: The proliferation of ZR-75-1 cells transfected with wild-type PTEN plasmid was significantly inhibited and accompanied with some apoptosis. Compared with untransfected and phosphatase-deficient PTEN plasmids, ZR-75- 1 cells, the difference of cell proliferation inhibition rate was statistically significant (42.7% vs.0% and 2.7%, P <0.01). The cell proliferation inhibitory effect increased with the increase of cell culture time and plasmid concentration. However, there was no significant difference in cell proliferation inhibition between PTEN plasmid transfected with phosphatase and ZR-75-1 transfected without plasmid (2.7% vs.0%, P> 0.05). The expression of PTEN protein in ZR-75-1 cells transfected with both PTEN plasmids was significantly higher than that in untransfected PTEN plasmids. The rates of adhesion inhibition and invasion inhibition were 65.7% and 70.4% The adhesion inhibition rate and invasion inhibition rate of phosphatase-deficient PTEN plasmid in ZR-75-1 cells were only 8.8% and 6.9%, respectively (P <0.05). CONCLUSION: The wild-type PTEN gene with bispecific phosphatase activity can inhibit the proliferation and metastasis of ZR-75-1 cells.