【摘要】 目的研究胃腺癌细胞对内质网应激诱导细胞凋亡耐受中BH3-only家族蛋白Noxa的表达、作用以及相关机制。方法衣霉素(TM)处理SGC-7901中分化胃腺癌细胞株及BGC-823低分化胃腺癌细胞株;采用PI单染法测定细胞凋亡率;Western blot法检测葡萄糖调节蛋白78(GRP78)、半胱天冬氨酸蛋白酶3(Caspase-3)、半胱天冬氨酸蛋白酶9(Caspase-9)、成人T细胞白血病诱导的PMA反应蛋白(Noxa)和髓样细胞白血病-1(Mcl-1)蛋白变化;小干扰RNA(siRNA)技术特异"沉默"Mcl-1和Noxa基因;实时荧光定量PCR检测Noxa mRNA水平变化。结果 TM处理胃腺癌细胞后,GRP78表达升高;胃腺癌细胞对TM诱导的内质网应激性凋亡耐受,Caspase-3和Caspase-9活化较弱;Noxa在蛋白水平和mRNA水平表达均升高;Mcl-1在蛋白水平表达升高;在SGC-7901细胞中,"沉默"Mcl-1基因会使细胞凋亡率升高,而双"沉默"Mcl-1和Noxa基因则细胞凋亡率明显下降。结论胃腺癌SGC-7901细胞在内质网应激状态下,Noxa的促凋亡作用被同样上调的Mcl-1抗凋亡作用拮抗,是胃腺癌细胞耐受内质网应激诱导凋亡的重要机制。更多还原

【Abstract】 Objective To investigate the role and mechanism of Noxa in resistance of gastric adenocarcinoma cells to endoplasmic reticulum(ER) stress-induced apoptosis.Methods Apoptosis was measured by flow cytometry using propidium iodide staining.The activation of Caspase-3,Caspase-9 and protein levels of GRP78,Noxa,Mcl-1 were detected by Western blot.The expression of Noxa mRNA was monitored by quantitative RT-PCR.Silencing of gene Mcl-1,Noxa expression was accomplished by small interfering RNA(siRNA) techniques.Results Gastric adenocarcinoma cells were generally resistant to apoptosis induced by the ER-stress inducer tunicymicin(TM).Exposure of TM resulted in less activation of Caspase-3 and Caspase-9 in gastric adenocarcinoma cells.The expression of Noxa and Mcl-1 were increased in protein level.Inhibiting Mcl-1 expression by siRNA in SGC-7901 cells increased the cell apoptosis.In contrast,inhibition of Noxa and Mcl-1 partially blocked tunicamycin-induced apoptosis in SGC-7901 cells.Conclusion Pro-apoptotic Bcl-2 family member Noxa is critical in gastric adenocarcinoma cells and the role of pro-apoptotic of Noxa is neutralized by the anti-apoptotic protein Mcl-1,which is also increased by ER stress.更多还原