上调NDRG1基因表达对肺腺癌细胞增殖与凋亡的影响

［摘要］目的: 建立稳定转染N myc下游调节基因1（N-myc downstream regulated gene 1，NDRG1）的A549细胞株,探讨NDRG1对A549细胞增殖与凋亡的影响及其可能的分子机制。方法: 经脂质体介导将含有NDRG1的重组表达质粒转染人肺腺癌A549细胞株，采用G418筛选阳性细胞克隆并进行实时荧光定量PCR（qRT-PCR）、蛋白质印迹鉴定；qRT-PCR和蛋白质印迹检测阳性细胞克隆P21及鼠双微体基因2（murine doubleminute 2，MDM2）的表达；MTT比色法检测阳性细胞克隆的增殖活性；流式细胞仪检测阳性细胞克隆凋亡率。结果: 成功建立高表达NDRG1的阳性A549细胞克隆（N11）；N11细胞P21表达及细胞凋亡率显著增高（P<0.05），而MDM2表达及细胞增殖显著降低（P<0.05）。结论: 上调A549细胞NDRG1表达后，细胞凋亡增加而细胞增殖降低，其作用机制可能与P21表达增高而MDM2表达降低有关。

Effect of up-regulating the NDRG1 gene expression on lung adenocarcinoma cells proliferation and apoptosis

Objective： To evaluate the effect and mechanism of N-myc downstream-regulated gene 1（NDRG1） on the proliferation and apoptosis of lung adenocarcinoma cells.Methods： pcDNA3.0-NDRG1 and pcDNA3.0 were transfected into A549 cells by lipofectamine;and positive clones were screened by G418.Quantitative real time polymerase chain reaction（qRT-PCR） and western blotting were used to identify mRNA and protein expressions of NDRG1 in A549 cells,respectively.The expressions of P21 and marine doubleminute 2（MDM2） in positive clones were detected by qRT-PCR and western blotting.The cell proliferation and apoptosis were observed by MTT assay and flow cytomertry.Results： Positive clone N11 with NDRG1 over-expression were successfully established.Compared with non-transfected control group,the expression of P21 and the apoptosis of N11 were significantly increased,however,the expression of MDM2 and the proliferation of N11 were significantly decreased.Conclusions： NDRG1 transfection could effectively promote the apoptosis and inhibit the proliferation of A549 cells by upregulating P21 expression and downregulating MDM2 expression in A549 cells.