KDR为靶的siRNA抑制乳腺癌细胞增殖的体内外研究

Small interference RNAs directed against KDR gene inhibit the proliferation of breast cancer cells in vitro and in vivo

目的:采用化学修饰的小干扰RNA(siRNA)在体内外抑制含激酶插入区受体(KDR)基因表达,探讨化学修饰的siRNA介导的RNA干扰(RNA i)技术在乳腺癌基因治疗的可行性和特异性。方法:采用阳离子脂质体L ipofectam ine2000TM作为转染试剂将针对人KDR基因的siRNA转染人类乳腺细胞株MCF-7,诱导RNA i,采用四甲基偶氮唑蓝(MTT)法,RT-PCR,Western blot试验等检测KDR基因和蛋白表达及细胞增殖变化。采用阳离子聚合物纳米粒In vivojetPEITM为转染试剂将siRNA直接注射进裸鼠移植瘤,监测肿瘤生长变化,RT-PCR,免疫组化方法等监测KDR基因和蛋白表达变化。结果:靶向KDR基因siRNA转染MCF-7后,细胞增殖被抑制,KDRmRNA和蛋白的表达明显降低;裸鼠体内实验显示siRNA治疗组瘤组织的增长受到明显抑制;RT-PCR,免疫组化结果同时表明治疗组KDR表达下调。各对照组指标无明显变化。结论:化学修饰的siRNA介导的RNAi在体内外均能成功抑制靶基因的表达和MCF-7细胞增殖,是潜在的肿瘤治疗新方法,而KDR亦可作为肿瘤治疗的新靶点。

AIM： To inhibit kinase insert domain-containing receptor （KDR） expression chemically modified siRNA in vitro and in vivo and to investigate the feasibility and specificity of gene therapy for breast cancer. METHODS： In vitro, siRNA was transfected into MCF-7 cells to induce RNAi by using cationic liposome Lipofectamine2000TM. The changes of KDR mRNA and protein expression in both siRNA treatment group and control group were measured by MTT assay and RT-PCR, In vivo, the siRNA was transfected into transplanted tumor in nude mice by using cationic polymer nanoparticle In vivo jetPEITM. Tumor growth was observed. The mRNA and protein expression of KDR was measured by RT-PCR and immunohistochemical staining. RESULTS： Experiments in vitro showed that siRNA directed against KDR effectively inhibited the proliferation of MCF-7 cells and downregulated KDR mRNA expression. In vivo, the growth of tumor was visibly suppressed. Furthermore, RT-PCR and immunohistochemical results indicated that KDR mRNA and protein expression was reduced in excised tumors. CONCLUSION： RNAi mediated by chemically modified siRNA markedly decreased KDR gene expression and inhibited cellular proliferation. It may have the potential as a therapeutic method to treat human cancer.