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

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.