livin在人胃癌组织中的表达及其沉默后对胃癌细胞凋亡的影响

目的探讨凋亡抑制蛋白livin在人胃癌组织中的表达及其与临床病理的关系,研究小分子干扰RNA(siRNA)对胃癌细胞系(SGC-7901)livin基因表达的抑制作用,以及livin基因沉默后对胃癌细胞凋亡的影响。方法采用RT-PCR方法和Western blot法检测胃不同组织中livin基因mRNA和蛋白的表达,分析livin表达与临床病理的关系;设计两条针对人源livin基因的siRNA,分别转染SGC-7901细胞;RT-PCR法检测转染前后livin基因的表达情况,四甲基偶氮唑盐(MTT)法检测转染前后细胞增殖能力的变化以及细胞对5-氟尿嘧啶(5-Fu)、顺铂的半数抑制浓度(IC_(50))的改变,流式细胞术检测转染前后细胞凋亡变化。结果40例胃癌组织中,livin表达阳性率为47.5%(19/40);在癌旁组织和良性病变胃黏膜组织中,livin表达呈阴性。组织分化程度差、淋巴结转移者的livin表达率高(P<0.05)。livin特异性siRNA转染48h后,SGC-7901细胞中的livin mRNA表达受到抑制,细胞增殖能力减弱,对5-Fu和顺铂凋亡敏感性增加,同时IC_(50)降低(P<0.05)。结论livin在胃癌组织中表达增高,且与组织分化程度和淋巴结转移有关,可作为辅助胃癌预后判断的分子标志之一;RNA干扰可明显抑制livin基因表达,并使胃癌细胞的凋亡敏感性增加;livin有可能成为通过诱导细胞凋亡增强胃癌治疗效果的一个分子靶点。

Expression of livin in gastric cancer and effect of silencing of the livin gene on apoptosis in gastric cancer cells

Objective The aim of this study was to detect the expression of livin in human gastric carcinoma and analyze the relationship between livin expression and cliniopathologic features.To explore the feasibility of small interference RNA (siRNA) in inhibition of livin gene expression and to investigate the apoptosis susceptibility of SGC-7901 cells by siRNA-mediated silencing of the livin gene.Methods The expression of iivin at mRNA and protein levels were determined by RT-PCR and Western blot assay, respectively.The relationship between livin expression and clinicopathologic features was analyzed.Two siRNAs specifically targeting livin gene were designed and synthesized in vitro,and were transfeeted into the gastric cancer SGC-7901 cells.The expression of livin mRNA was assayed by RT-PCR.Cell growth state and 50% inhibition concentration (IC_(50)) of 5-Fu and cisplatin on SGC-7901 cells were determined by MTT method.Cell apoptosis was assessed by flow cytometry (FCM).Results The expressions of livin mRNA and protein were detected in 19 of 40 gastric carcinoma cases (47.5%).No expression of livin was detected in tumor-adjacent tissues and benign gastric lesion.A positive correlation was found between livin expression and poor differentiation as well as lymph node metastases (P<0.05).The level of livin mRNA was decreased in the SGC-7901 cells transfected by si-livinl for 48 hours,with inhibition of cell growth.IC_(50) of si-livin-treated SGC-7901 cells to 5-Fu and cisplatin was decreased (P<0.05) and the cells were more susceptible to proapoptotic stimuli (5-Fu and cisplatin) than control groups (P<0.05).Conclusion Livin is overexpressed in gastric carcinoma with a correlation to tumor differentiation and lymph node metastasis, suggesting that it may be as one of molecular prognostic factors for some cases of gastric cancer.SiRNA can inhibit livin expression of SGC-7901 cells and induce cell apoptosis.Livin might serve as a new target for apoptosis-inducing therapy of gastric cancer.