RNA干扰沉默IGFBP2基因表达抑制裸鼠移植瘤的生长

目的：应用RNAi技术沉默胰岛素生长因子结合蛋白2基因（IGFBP2）,探讨其对人胃癌移植瘤生长的影响。方法：合成靶向IGFBP siRNA的表达质粒,于雌裸鼠皮下种植SGC7901胃癌细胞,肿瘤长至一定大小时,随机分为重组质粒实验组（A）,阴性质粒对照组（B）及盐水对照组（C）,于肿瘤局部分别注射重组质粒、阴性重组质粒、生理盐水。每3d给药一次,共8次,3d测量一次肿瘤体积,22d后处死全部动物,取肿瘤,测其大小和瘤重,RT-PCR检测各组IGFBP-2的表达。结果：A组肿瘤瘤块的体积和重量明显小于B、C组（P〈0.05）,RT-PCR显示,A组IGFBP-2的表达明显低于B、C组（P〈0.05）,B、C组IGFBP-2的表达差异无显著性（P〉0.05）。结论：靶向IGFBP-2siRNA瘤内注射能显著地延缓胃癌细胞裸鼠皮下移植瘤的生长,可能通过抑制IGFBP-2基因表达的机制抑制细胞增殖。

Silence Insulin-Like Growth Factor Binding Protein-2 Gene Expression with RNA Interference Retards Growth of Xenografts of Gastric Cancer in Nude Mice

Objective To observe the growth of gastric cancer xenografts in nude mice after applying RNAi technique to silence insulin-like growth factor binding protein-2.Methods ①Synthesize siRNA targeting IGFBP2,②SGC7901 gastric cancer cells were implanted under the skin of female nude mice.After the tumors grew to a definite size,the mice were randomly divided into three groups： the experimental group （A） ,negative control group （B） ,saline control group （C） .The Group A animals were treated with intra-tumoral injection of recombined plasmid with IGFBP-2 siRNA 20μg q3d ×8.Group B animals were treated with negative siRNA and Group C animals were treated with normal saline.Measure tumor volume every 3days.After 20 days,the animals were sacrificed and the tumors were taken out,their size and weight were measured,gene expression of IGFBP-2 were examined with RT-PCR.Results The size and the weight of tumor group A animals were significantly less than those of group B and C （P〈 0.05） .RT-PCR show that expression of IGFBP-2 gene in group A were significantly lower than that in group B and C （P〈 0.05） and there were no significant differences between group B and group C （P〈 0.05） .Conclusion siRNA targeting IGFBP-2 intratumoral injection can significantly retard the growth of gastric cancer xenografts in nude mice,probably by inhibiting IGFBP-2 gene with inhibition of proliferation.