用siRNA研究IQGAP1基因调控STAT3信号对脑胶质瘤细胞生物学特性的影响

Effect of IQGAP1 siRNA on biological characteristics of glioma cells by regulating STAT3 signaling pathway

目的:探讨敲减IQGAP1基因表达对脑胶质瘤细胞侵袭、迁移及免疫抑制的影响及机制。方法:将人脑胶质瘤U251细胞随机分为空白组、阴性对照组和si-IQGAP1组,AG490作为STAT3信号通路抑制剂。转染48 h后,MTT法检测细胞活力;Western blot检测IQGAP1、血管内皮生长因子(VEGF)、转化生长因子β1(TGF-β1)、STAT3和p-STAT3的蛋白水平;Transwell小室检测细胞的侵袭和迁移能力。结果:si-IQGAP1-1组和si-IQGAP1-2组的IQGAP1蛋白表达均显著低于空白组(P<0.05)。与空白组比较,si-IQGAP1组和AG490组的细胞活力、侵袭能力和迁移能力均显著降低,VEGF、TGF-β1和p-STAT3的蛋白水平均显著降低(P<0.05)。与AG490组比较,AG490+si-IQGAP1组的细胞活力、侵袭能力和迁移能力均显著降低,VEGF和TGF-β1的蛋白表达均显著降低(P<0.05)。结论:敲减IQGAP1基因表达可降低脑胶质瘤细胞的侵袭和迁移能力,减弱细胞免疫抑制因子VEGF和TGF-β1的表达,机制与下调STAT3信号通路有关。

AIM:To investigate the effect of IQGAP1 gene expression knock-down on invasion,migration and immunosuppression of glioma cells and its mechanism.METHODS:Human glioma U251 cells were randomly divided into blank group,negative control group and si-IQGAP1 group.AG490,an inhibitor of STAT3 signaling pathway,was used to treat the cells for 48 h.The cell viability was measured by MTT assay.The protein levels of IQGAP1,vascular endothelial growth factor(VEGF),transforming growth factor-β1(TGF-β1),STAT3 and p-STAT3 were determined by Western blot.The cell invasion and migration abilities were detected by Transwell assays.RESULTS:The protein expression of IQGAP1 in si-IQGAP1-1 group and si-IQGAP1-2 group was significantly lower than that in blank group(P<0.05).Compared with blank group,the viability,the invasion ability and the migration ability of the cells in si-IQGAP1 group and AG490 group were significantly decreased,while the protein levels of VEGF,TGF-β1 and p-STAT3 were significantly decreased(P<0.05).Compared with AG490 group,the cell viability,invasion ability and migration ability in AG490+si-IQGAP1 group were significantly decreased,and the protein levels of VEGF and TGF-β1 were significantly decreased(P<0.05).CONCLUSION:Silencing of IQGAP1 gene expression reduces the invasion and migration abilities of glioma cells and decreases the protein expression of cellular immunosuppression molecules VEGF and TGF-β1,which is related to down-regulation of STAT3 signaling pathway.