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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。
Objective To investigate the expression of livin in human gastric cancer and its relationship with clinicopathological features and to study the inhibitory effect of siRNA on livin gene expression in gastric cancer cell line SGC-7901 and the silencing of livin gene On the apoptosis of gastric cancer cells. Methods RT-PCR and Western blot were used to detect the expression of livin mRNA and protein in different tissues of gastric tissues. The relationship between livin expression and clinical pathology was analyzed. Two siRNAs targeting human livin gene were designed and transfected into SGC-7901 cells The expression of livin gene was detected by RT-PCR before and after transfection. The proliferation of cells was detected by MTT assay and the effect of 5-fluorouracil (5-Fu), cisplatin Half inhibitory concentration (IC 50) changes, flow cytometry detection of apoptosis before and after transfection. Results The positive expression rate of livin was 47.5% (40/40) in 40 cases of gastric cancer tissues. The expression of livin was negative in the paracancerous tissues and benign gastric mucosa tissues. Tissue differentiation was poor, lymphatic metastasis of livin expression was high (P <0.05). The livin mRNA expression in SGC-7901 cells was inhibited 48h after livin-specific siRNA transfection, and the cell proliferation was weakened. The sensitivity of 5-Fu and cisplatin to apoptosis was increased and the IC 50 was decreased (P <0.05) . Conclusion The expression of livin in gastric cancer tissue is increased, and it is related to the degree of tissue differentiation and lymph node metastasis, which can be used as one of the molecular markers to assist the prognosis of gastric cancer. RNA interference can significantly inhibit the expression of livin gene and increase the apoptosis sensitivity of gastric cancer cells ; livin may become a molecular target of enhancing the therapeutic effect of gastric cancer by inducing apoptosis.