肿瘤坏死因子相关凋亡诱导配体诱导胶质瘤细胞凋亡机制研究

目的 探讨肿瘤坏死因子相关凋亡诱导配体(TRAIL)诱导胶质瘤细胞凋亡的机制.方法 以人重组可溶性TRAIL蛋白(rsTRAIL)处理人胶质瘤细胞U87;AnnexinV-FITC/PI双染色流式细胞术检测细胞凋亡;DiOC6荧光染色流式细胞术检测细胞线粒体跨膜电位(△ψm);比色法测定细胞caspase-3、8、9活性的变化;ELISA法检测胞浆cytC浓度;观察caspase-8阻断剂(Z-IETD-fmk)对U87细胞凋亡、△ψm和caspase-3、8、9活性变化的影响. 结果 rsTRAIL以时间依赖方式诱导U87细胞凋亡.同时导致U87细胞△ψm进行性下降,caspase-3、8、9活性及胞浆内cyt C浓度升高:caspase-8阻断剂可明显减弱rsTRAIL对U87细胞的上述生物学效应. 结论 TRAU通过激活caspase-8间接启动线粒体凋亡途径诱导恶性胶质瘤细胞U87凋亡.

Tumor necrosis factor-related apoptosis-inducing ligand induces glioma U87 cell apoptosis through the mitochondrial apoptotic pathway

Objective To study the mechanism of tumor necrosis factor-related apoptosis-inducing ligand(TRAIL)-induced apoptosis of glioma U87 cells.Methods Human glioma U87 cells were treated with human recombinant soluble TRAIL(rsTRAIL),and the cell apoptosis was detecmd with flow cytometry with AnnexinV-FITC/PI double staining.Flow cytometry with DiOC6 staining was used to assess the changes in mitochondrial transmembrane potential(△ψm).The relative activity of caspase-3,-8 and-9 Was measmed by colorimetric assay,and the concentration of cytoplasmic cytochrome C(cyt C) determined using enzyme-linked immunosorbem assay.The effects ofcaspase-8 inhibitor(Z-IETD-fmk)on rsTRAIL-induced apoptosis,△ψm,caspase-3,-8 and-9 activities and cyt C concentration were observed. Results RsTRAIL tinle-dependently induced apoptosis and progressive collapse of △ψm in glioma U87 cells,resulting also in caspase-3,-8 and-9activation and elevated cytC concentration.Caspase-8 inhibitor partially antagonized these biological effects induced by rsTRAIL in U87 cells.Conclusion TRAIL initiates a cascade of mitochondrial events by activating caspase-8 and induces apoptosis of glioma U87 cells.