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目的探讨腺病毒载体介导的早幼粒细胞白血病基因(PML)生长抑制因子诱导胃癌细胞凋亡作用的机制。方法将人PML全长cDNA插入穿梭质粒pSGCMV,再与腺病毒骨架质粒pPE3共转染293细胞后获得重组病毒。用重组病毒感染胃癌细胞系SGC-7901,采用噻唑蓝比色法、流式细胞术以及免疫细胞化学法对p53和bcl-2在肿瘤细胞内的表达以及细胞凋亡的定性与定量指标进行检测。结果经腺病毒介导的PML处理的SGC-7901细胞生长受到明显抑制,凋亡细胞发生率升高,且与MOI值呈正相关,MOI值由5增加到20,细胞的生长抑制率从22．4％增加到38．5％,而细胞凋亡率从37．2％增加到49．8％。经腺病毒介导的PML处理的SGC-7901细胞内p53蛋白表达较对照组明显增加,bcl-2蛋白的表达则无明显变化。结论腺病毒介导的PML对胃癌细胞的杀伤主要是通过诱导细胞凋亡,p53蛋白高表达为其诱发胃癌细胞凋亡的机制之一。
Objective To investigate the mechanism of adenovirus vector-mediated promyelocytic leukemia gene (PML) growth inhibitory factor in gastric cancer cell apoptosis. Methods The full-length cDNA of human PML was inserted into the shuttle plasmid pSGCMV. The recombinant plasmid was co-transfected into 293 cells with adenovirus backbone plasmid pPE3. The recombinant adenovirus was used to infect gastric cancer cell line SGC-7901. The expression of p53 and bcl-2 in tumor cells and the qualitative and quantitative indexes of apoptosis were detected by thiazolyl blue colorimetric assay, flow cytometry and immunocytochemistry . Results The growth of SGC-7901 cells treated with adenovirus mediated PML was significantly inhibited. The incidence of apoptotic cells was increased, and it was positively correlated with the MOI. The MOI increased from 5 to 20 and the growth inhibition rate of cells from 22. 4% to 38.5%, while the apoptosis rate increased from 37.2% to 49.8%. The expression of p53 protein in SGC-7901 cells treated with adenovirus-mediated PML increased significantly compared with the control group, while the expression of bcl-2 protein did not change significantly. Conclusion Adenovirus-mediated killing of human gastric cancer cells by PML is mainly through induction of apoptosis and high expression of p53 protein as one of the mechanisms of gastric cancer cell apoptosis.