pEgr-sTRAIL体外转染联合^(60)Co γ射线照射诱导肿瘤细胞凋亡及Caspase-3活化

pEgr-sTRAIL TRANSFER IN COMBINATION WITH ^(60)Co γ RAY IRRADIATION TO INDUCE THE APOPTOSIS ON HeLa CELLS AND ACTIVATION OF Caspase-3

为探讨Egr-1启动子调控TRAIL基因表达的辐射增敏作用及其作用机制,采用体外瞬时转染pEgr-sTRAIL辐射诱导表达载体联合不同剂量60Coγ射线照射,观察其诱导肿瘤细胞凋亡的作用及其与凋亡执行分子Caspase-3活化的关系。结果表明重组质粒体外瞬时转染联合不同剂量60Coγ射线照射可诱导肿瘤细胞凋亡,并具有随剂量增高而增加的趋势。Western blot及分光光度法检测Capase-3活性均显示转染重组质粒pEgr-sTRAIL接受不同剂量γ射线照射后,其Caspase-3活性明显增高,亦有随着剂量增高而增高的趋势。提示γ射线可通过激活Egr-1启动子增加TRAIL诱导凋亡及活化Caspase-3的作用从而提高肿瘤细胞的辐射敏感性。

In order to approach the radiosensitivity of TRAIL expression controlled by Egr-1 promotor, the recombinant vector pEgr-sTRAIL was tranfected into HeLa cells, the early apoptosis and Caspase-3 activity were detected after different doses of ^60Co γ-ray irradiation. The results showed that pEgr-sTRAIL transfected in combination with γ-ray irradiation could significantly induce the apoptosis of HeLa cells in a dose-dependent manner. The higher activity of Capase-3 was also found in pEgr-sTRAIL irradiated group by using western blotting and spectrophotometry. Our result demonstrated that the activity of Caspase-3, as the apoptosis executor, play an important role in TRAIL-induced apoptosis and the enhanced TRAIL-induced apoptosis in transfected ceils after irradiation can be controlled by radio-sensitive promoter Egr-1.