奥沙利铂对TRAIL诱导胃癌BGC823细胞凋亡的增强作用

Oxaliplatin enhances TRAILinduced apoptosis of gastric cancer BGC823 cells

目的:探讨奥沙利铂和肿瘤坏死因子相关凋亡诱导配体(TRAIL)对胃癌BGC823细胞联合作用的机制.方法:不同浓度的TRAIL和/或奥沙利铂作用于人胃癌细胞系BGC823细胞,MTT检测细胞增殖能力.流式细胞术PI染色检测细胞凋亡.TRAIL和/或奥沙利铂作用BGC823细胞后,用抗CTX-B,抗死亡受体4(DR4)和罗丹明标记的荧光二抗染色.免疫荧光显微技术检测脂筏和DR4在细胞膜的分布.结果:1-1000μg/L的TRAIL作用BGC823细胞24h,细胞增殖抑制率不超过20%.100μg/L的TRAIL对细胞的增殖抑制率在10%左右.100μg/L的TRAIL作用BGC823细胞24h,诱导4.12%±1.26%的细胞凋亡.1-50mg/L奥沙利铂处理BGC823细胞24h,抑制细胞增殖50%的药物浓度(IC50)为37.36mg/L±8.12mg/L.与单药奥沙利铂相比,奥沙利铂(38mg/L,24h的IC50)联合TRAIL(100μg/L)作用24h,细胞凋亡比率明显提高(19.83%±4.21%vs40.42%±5.78%,P<0.05).与对照组相比,100μg/L的TRAIL作用BGC823细胞24h,没有引起明显的脂筏聚集或DR4聚集.奥沙利铂(38mg/L)明显促进脂筏聚集和DR4聚集,同时观察到DR4和脂筏的共定位.奥沙利铂和TRAIL联合作用24h,同样观察到DR4定位在聚集的脂筏内.结论:奥沙利铂通过促进DR4在脂筏聚集增强TRAIL诱导的胃癌BGC823细胞凋亡.

AIM： To determine whether there is a synergistic effect between oxaliplatin and tumor necrosis factorrelated apoptosisinducing ligand （TRAIL） in inducing the apoptosis of gastric cancer BGC823 cells. METHODS： After BGC823 cells were cultured and treated with TRAIL and/or oxaliplatin, cell proliferation was measured using MTT assay; cell apoptosis was determined by flow cytometry after propidium iodide staining; and the distribution of lipid rafts and death receptors 4（DR4） on cell membrane was analyzed by immunofluorescence staining with anticholera toxin B subunit, antiDR4 antibody and rhodamineconjugated ？ uorescent secondary antibody. RESULTS： After BGC823 cells were treated with 11 000 μg/L TRAIL for 24 h, the reduced rates of cell proliferation did not exceed 20%. Treatment with 100 μg/L TRAIL for 24 h induced about 10% inhibition of cell proliferation and 4.12% ± 1.26% cell apoptosis. After BGC823 cells were treated with 150 mg/L oxaliplatin for 24 h, it was found that the half maximal inhibitory concentration （IC50） was 37.36 mg/L ± 8.12 mg/L. Treatment with oxaliplatin （38 mg/L, IC50 dose） plus TRAIL resulted in a dramatic increase in cell apoptosis when compared to treatment with TRAIL alone （19.83% ± 4.21% vs 40.42% ± 5.78%, P 0.05）. TRAIL at a concentration of 100 μg/L did not induce obvious lipid raft aggregation or DR4 clustering. Oxaliplatin （38 mg/L） signif icantly promoted lipid raft aggregation and DR4 clustering and induced the colocalization of DR4 and lipid rafts. Treatment with oxaliplatin and TRAIL for 24 h also induced DR4 clustering into aggregated lipid rafts. CONCLUSION： Oxaliplatin enhances TRAILinduced BGC823 cell apoptosis by clustering DR4 into lipid rafts.