PTEN基因对胶质瘤细胞增殖及侵袭性影响的体外研究

目的探讨PTEN基因转染人胶质瘤U251细胞后对其增殖及侵袭性的影响。方法应用脂质体转染技术,将含PTEN基因重组表达质粒转染U251细胞系,Western blot鉴定其蛋白表达;应用四甲基偶氮唑蓝比色(MTT)法观察对细胞株生长的影响;流式细胞仪检测细胞周期及凋亡;应用免疫组化检测转染PTEN的U251细胞基质金属蛋白酶(MMP-2、MMP-9)和金属蛋白酶抑制剂(TIMP-1、TIMP-2)的表达变化。结果 PTEN质粒成功转染U251细胞并有PTEN蛋白的表达。与对照组、空载体组相比,转染组细胞生长抑制率下降达52.46%;细胞周期改变,细胞从G1期到S期发生阻滞;转染组MMP-2、MMP-9表达显著下降,而TIMP-1、TIMP-2表达显著上升,两者呈负相关(r=-0.506,P<0.05)。结论 PTEN转染人胶质瘤细胞系U251后,可抑制其增殖、促进凋亡;并可能通过抑制MMPs和促进TIMPs来抑制细胞侵袭性。

Effect of PTEN gene transfection on growth and invasion in human glioblastoma cell line U251

Objective To investigate the inhibitory effect of wild-type phosphatase and tensin homolog deleted on chromosome ten(PTEN) gene on the growth and invasion of human glioblastoma cell line U251.Methods Recombinant plasmid pEGFP-PTEN containing wild-type PTEN gene segment was transferred into U251 cells by liposome transfection technique,and the transfection was identified by Western blotting.Cell growth was analyzed by MTT assay,and cell cycle and apoptosis were examined by flow cytometry.The protein levels of matrix metalloproteinase-2(MMP-2),matrix metalloproteinase-9(MMP-9),tissue inhibitor of metalloproteinase-1(TIMP-1) and tissue inhibitor of metalloproteinase-2(TIMP-2) were detected by immunohistochemical method.Results The recombinant plasmid pEGFP-PTEN was successfully transferred into U251 cells,and PTEN protein expression was detected.Compared with those of the control group and empty vector group,the rate of cell growth inhibition decreased to 52.46%.The cell cycle was arrested at G1/S phase.The expression levels of MMP-2 and MMP-9 decreased significantly in the transfection group,while those of TIMP-1 and TIMP-2 significantly increased and were negatively correlated with the expression levels of MMP-2 and MMP-9(r=-0.506,P<0.05).Conclusion PTEN gene transfection can inhibit the growth of human glioblastoma U251 cell line,induce cell apoptosis,and inhibit cell invasion by downregulating MMPs and upregulating TIMPs.