BIRC5高表达在胃癌中增强细胞活力、抑制凋亡并与预后不良相关

High expression of BIRC5 enhances cell viability,inhibits apoptosis and is associated with poor prognosis in gastric cancer

目的:探讨含杆状病毒凋亡抑制蛋白重复序列蛋白5(BIRC5)在胃癌组织中的表达及其与胃癌患者预后的关系,并通过敲减BIRC5表达探讨BIRC5对胃癌细胞活力和凋亡的影响。方法:收集67例胃癌组织和癌旁组织,采用免疫组化检测BIRC5表达,并分析BIRC5表达与胃癌临床病理特征和预后的关系。采用RT-qPCR和Western blot检测胃癌细胞系AGS、MKN-1和MGC-803及正常胃上皮细胞系GES-1中BIRC5的mRNA和蛋白表达。将胃癌细胞系AGS分为blank组(不做任何处理)、Ctr-sh组(转染空白质粒)和BIRC5-sh组(转染BIRC5-shRNA质粒),用Western blot检测BIRC5-shRNA的干扰效率,MTT法检测各组细胞活力,流式细胞术检测各组细胞凋亡情况,Western blot检测凋亡相关蛋白cleaved caspase-3、Bax和Bcl-2的表达水平。结果:BIRC5主要表达在细胞质中,胃癌组织中BIRC5阳性表达率高于癌旁组织(P<0.01)。TNM分期为Ⅲ~Ⅳ期及淋巴结转移的胃癌患者BIRC5阳性率分别高于TNM分期为Ⅰ~Ⅱ期及无淋巴结转移的胃癌患者(P<0.05)。BIRC5阳性表达患者的生存期短于BIRC5阴性表达患者(P=0.0112)。在AGS细胞中敲减BIRC5的表达,结果发现48、72和96 h的BIRC5-sh组细胞活力均低于相应时点的blank组和Ctr-sh组,BIRC5-sh组的细胞凋亡率高于blank组和Ctr-sh组,cleaved caspase-3和Bax的蛋白水平高于blank组和Ctr-sh组,Bcl-2的蛋白表达低于blank组和Ctr-sh组(均P<0.05)。结论:胃癌中BIRC5高表达,这预示不良预后;BIRC5可以促进胃癌细胞生长,抑制细胞凋亡。

AIM:To investigate the expression of baculoviral inhibitor of apoptosis protein repeat-containing protein 5(BIRC5)in gastric cancer tissue and its relationship with prognosis of gastric cancer patients,and to explore the effect of BIRC5 knock-down on the viability and apoptosis of gastric cancer cells.METHODS:The expression of BIRC5 was detected by immunohistochemistry in 67 cases of gastric cancer tissues and paracancerous tissues for analyzing the re⁃lationships with clinicopathological characteristics.The mRNA and protein expression levels of BIRC5 in gastric carcino⁃ma cell lines(AGS,MKN-1 and MGC-803)and normal gastric epithelial cell line GES-1 were detected by RT-qPCR and Western blot.The AGS cells were divided into blank group(no treatment),Ctr-sh group(blank plasmid transfection)and BIRC5-sh group(BIRC5-shRNA plasmid transfection).The interference efficiency of BIRC5-shRNA was evaluated by Western blot.The cell viability was measured by MTT assay,the apoptosis was analyzed by flow cytometry,and the levels of apoptosis-related proteins cleaved caspase-3,Bax and Bcl-2 were determined by Western blot.RESULTS:BIRC5 was mainly expressed in cytoplasm,and the positive expression rate of BIRC5 in the gastric cancer tissues was higher than that in the adjacent tissues(P<0.01).The positive rates of BIRC5 in the gastric cancer patients at TNMⅢ~Ⅳstages and with lymph node metastasis were higher than those in the patients at TNMⅠ~Ⅱstages and without lymph node metastasis,re⁃spectively(P<0.05).The survival time of the patients with positive BIRC5 expression was shorter than that of the patients with negative BIRC5 expression(P=0.0112).The cell viability in BIRC5-sh group was lower than that in blank group and Ctr-sh group at time points of 48,72 and 96 h.The apoptotic rate in BIRC5-sh group was increased compared with blank group and Ctr-sh group.The protein levels of cleaved caspase-3 and Bax in BIRC5-sh group were higher than those in blank group and Ctr-sh group,while the protein expression of Bcl-2 in BIRC5-sh group was lower than that in blank group and Ctr-sh group(P<0.05).CONCLUSION:High expression of BIRC5 in gastric cancer indicates poor progno⁃sis.BIRC5 promotes the growth of gastric cancer cells and inhibits apoptosis.