抑制MEK/ERK消除胃腺癌细胞对内质网应激性凋亡的耐受  

Overcome the resistance of gastric cell lines to apoptosis induced by the ER stress inducers by inhibiting MEK/ERK pathway

作　　者：陈思[1] 吴萍[1] 江蓓蕾[1] 程文晋[1] 罗畅民[1] 张旭东[1] 张林杰[1] 

机构地区：[1]安徽医科大学免疫学教研室,合肥230032

出　　处：《安徽医科大学学报》2008年第1期1-4,共4页Acta Universitatis Medicinalis Anhui

基　　金：国家自然科学基金项目(编号:30572118);安徽省自然科学基金项目(编号:070413077)

摘　　要：目的了解内质网应激诱导胃腺癌细胞凋亡情况及其作用途径,并探讨MEK/ERK信号途径在其中发挥的作用。方法流式细胞仪PI单染法检测细胞周期DNA含量分析凋亡率,DAPI染色后荧光显微镜观察药物处理后死亡细胞形态特征及各组死亡差别,免疫印迹法(Western blot)检测衣霉素以及U0126诱导前后p-ERK、caspase-3、PARP的表达变化。结果不同浓度衣霉素(TM)诱导胃腺癌细胞48h凋亡率最高仅为15.65%,TM诱导ERK活化形式p-ERK表达增加,而在U0126处理后下调。U0126与TM共同作用于胃腺癌细胞时,凋亡率显著升高至38.3%±2.78%。荧光显微镜可观察到细胞内典型的凋亡小体,凋亡细胞比TM单独作用明显增多。U0126作用后TM诱发胃腺癌细胞caspase-3、PARP剪切、活化。结论TM可诱导胃腺癌细胞发生内质网应激反应性凋亡并且激活MEK/ERK信号通路,但对其相对不敏感。通过阻断MEK/ERK信号途径后能杀死大量胃腺癌细胞,caspase-3、PARP的活化表明胃腺癌细胞的内质网应激性凋亡依赖于caspase途径。Objective To clarify the sensitivity and the pathway of apoptosis of ER stress-induced gastric adenocarcinoma cells,and investigate the role of MEK/ERK pathway in ER stress-induced apoptosis. Methods Apoptosis was analyzed by detecting the DNA content of cell cycle with PI staining in flow cytometry. Morphological characteristics of cell death and apoptotic contrast among the drug treatment group were examined with DAPI staining by fluorescence microscope. The expression level of p-ERK, caspase-3, PARP before and after tunicamycin, U0126 and the two co-treatment was assayed by immunoblotting（ Western blot）. Results The TM-induced apoptotic percentage of gastric adenocarcinoma cells peaked only at 15.65% with a range of concentration. The expression of p-ERK protein was increased after exposure to TM, but decreasd with U0126 pre-treated. The levels of apoptosis induced by TM in the presence of U0126 notably rose to 38.3% ＋ 2.78% in gastric cells. There were typical apoptotic bodies in death cells, and apoptotic cells with U0126 and TM co-treated could be more frequently observed than that with TM alone under fluorescent microscope. The cleavage and activation of caspase-3, PARP were induced by TM when cells pretreated with U0126. Conclusion TM can induce ER stress-mediated apoptosis and activate MEK/ERK signaling pathway in gastric adenocarcinoma cells, however, which are relatively resistant to TM. After blocking MEK/ERK pathway numerous cells are killed by TM. Activation of caspase-3, PARP indicates that ER stress-induced apoptosis in gastric adenocarcinoma cells is also capase-dependent.

关 键 词：胃肿瘤 内质网 细胞凋亡 信号传导 

分 类 号：R735.2[医药卫生—肿瘤] R392.2[医药卫生—临床医学]