中文摘要：

目的探讨程序性死亡基因4（PDCD4）对死亡相关蛋白5（DAP5）的表达及对人大肠癌细胞系LOVO凋亡的影响。方法构建重组真核表达载体pFLAG／PDCD4，转染人大肠癌细胞LOVO，G418（500rag／L）筛选获得稳定表达PDCD4的细胞系。RT—PCR及Western blotting检测LOVO细胞中PDCD4的mRNA及蛋白表达，流式细胞仪检测LOVO细胞凋亡情况，Western blotting检测LOVO细胞DAP5表达的变化。结果成功建立稳定表达PDCD4的大肠癌细胞LOVO—pFLAG／PDCD4。转染PDCD4的LOVO—pFLAG／PDCD4组与空白对照LOVO组、转染空载质粒的LOVO—pFLAG组相比，PDCD4蛋白表达和mRNA水平明显升高（P〈0．01）；细胞凋亡率明显增加（P〈0．01）；同时伴有DAP5蛋白表达明显升高（P〈0．01）。结论PDCD4能够诱导大肠癌细胞LOVO的凋亡，其机制可能与上调DAP5的表达有关。

英文摘要：

Objective To investigate the effect of exogenous programmed cell death 4 （PDCD4） gene on the expression of death associated protein 5 （DAPS） and apoptosis of human colorectal cancer cell LOVO, and involved mechanisms thereof. Methods Recombinant eukaryotic plasmid pFLAG/PDCD4 was constructed and transfeeted into human colorectal cancer cell LOVO. Cells stably expressing PDCD4 were established by G418 selection （500 mg/L）. The levels of PDCD4 protein and mRNA were analyzed by RT-PCR and Western blotting. The apoptotic cells were measured by flow eytometry, and protein expression of DAP5 was detected by Western blotting. Results LOVO-pFLAG/PDCD4 cell line was successfully established by G418 selection. Compared to non-transfection and mock-transfection group, the levels of PDCD4 mRNA and protein were significantly increased, the cell apoptosis ratio was enhanced and the expression of DAP5 protein was increased in transfection group （P 〈 0.01）. Conclusion PDCD4 could induce apoptosis of human colorectal cancer LOVO cells, which mechanism might be involved in up-regulating DAP5 protein.