摘要目的 观察靶向封闭EEF1A2基因对胰腺癌细胞株凋亡的影响,并探讨其可能的作用机制.方法 体外转录制备2对EEF1A2 siRNA,应用脂质体技术转染胰腺癌细胞株BxPC-3,半定量RT-PCR、蛋白质印迹法检测转染前后EEF1A2基因表达的变化.运用膜联蛋白V/碘化丙啶法检测细胞凋亡率;蛋白质印迹法检测细胞中caspase-3、caspase-8、caspase-9、聚二磷酸腺苷核糖多聚酶(PARP)细胞色素C和Bid等凋亡相关蛋白表达变化.结果 2对EEF1A2 siRNA均能有效降低BxPC-3细胞中EEF1A2的表达,其中第2对siRNA静默效果更佳,EEF1A2在mRNA和蛋白质水平的表达抑制率均达75%左右.抑制BxPC-3细胞中EEF1A2的表达后,细胞的早期凋亡率为15.28%±3.65%,显著高于阴性对照组的10.11%±3.05%和空白组的9.41%±4.14%,同时伴随出现caspase-3、caspase-8、caspase-9、PARP和Bid的蛋白活化增强和细胞色素C表达增加.结论 抑制EEF1A2表达能明显诱导胰腺癌细胞BxPC-3的凋亡,而死亡受体途径和线粒体途径的激活可能均参与凋亡的发生.

abstractsObjective To elucidate whether down-regulation of homo sapiens eukaryotic translation elongation factor 1 alpha 2 (EEF1A2) expression induces apoptosis in pancreatic cancer cells and its possible mechanisms. Methods Two siRNAs targeting human EEF1A2 were synthesized and the siRNA/liposome complexes were transfected into the pancreatic cancer cell line BxPC-3. RTPCR and Western blot were used to analyze the change of EEF1A2 expression and the apoptosis rate of BxPC-3 cells was studied using Annexin-V/PI assay. To identify the mechanisms involved, the apoptosis associated proteins such as caspase-3, caspase-8, caspase-9, PARP, cytochrome C and Bid were detected by Western blotting. Results Both EEF1A2-targeting siRNAs reduced the EEF1A2expression, and the No. 2 siRNA inhibited EEF1A2 expression to less than 25 % in mRNA and protein levels. Down-regulation of EEF1A2 expression in BxPC-3 cells enhanced cell apoptosis (15.28% ±3.65%) at a greater level than negative siRNA-expressing cells (10. 11% ± 3. 05%) or mock cells (9.41 % ±4.14 %). Furthermore, reduction of EEF1A2 activated the pro-caspase-8, pro-caspase-3,pro-caspase-9,PARP and Bid to their active forms, and increased the expression of cytochrome C.Conclusions These data suggest that EEF1A2 down-regulation could significantly induce apoptosis of pancreatic cancer cell line BxPC-3, which is likely mediated by the death receptor and mitochondrial apoptotic pathways.