Expression Of VEGF、STAT3and IGF-1R In Colorectal Carcinoma And Influence On Biological Characteristics Of HT29Cells By SiRNA-mediated Silencing VEGF Gene

Purpose:To investigate the expression and clinical significance of vascular endothelial growth factor(VEGF)、STAT3and IGF-IR in colorectal carcinoma and the Influence on Biological Characteristics of HT29cells by SiRNA-mediated Silencing VEGF Gene. Methods:The expression of VEGF、STAT3and IGF-IR was detected by immunohistochemistry S-P method in62cases of colorectal carcinoma and20cases of normal colorectal tissue. To knockdown VEGF expression,a small interfering RNA targeting against VEGF was synthesized and transfected into HT29cells with lipofectamine2000. The expression of VEGF protein was detected by Immunocytochemical staining (S-P method) and Western blot analysis. The effect of suppressing proliferation of cells was detected by MTT assay. The effect of inducing cells apoptosis was detected by flow cytometry(FCM). Results:(1)The expression of VEGF、STST3and IGF-1R were significantly higher in tumor tissue than those in normal tissue (P<0.05). The expression of VEGF and STAT3was positively correlated with lymph node metastasis and clinical stages (P<0.05).(2)VEGF protein was positively correlated with the expression of STAT3protein in the Colorectal cancer tissue.(3)VEGF protein was positively correlated with the expression of IGF-1R protein in the Colorectal cancer tissue.(4)Immunocytochemistry shows that:The HT29cell of the normal control group, Lip-2000control group and mismatch control group cytoplasm were positive expression (dark brown yellow), VEGF-siRNA group showed weakly positive expression in HT29cytoplasm(Light brown yellow); Western blot indicated that:The brightness of protein bands in VEGF-SiRNA were significantly lower than those of the normal control group, Lip-2000control group and mismatch control group.(5)MTT test results:Compared with negative control group, the VEGF-siRNA cell growth inhibition was significantly higher (P<0.05). Tumor cell proliferation rates were significantly higher than the same cell line with a VEGF-siRNA group at the different times (24h,48h,72h)(P<0.05), the effection showed time-dependence.(6)Flow cytometry results show that:compared with the blank control and negative control cells, VEGF-siRNA group have a apparent hypodiploid peak. Which indicating that the apoptosis rates of HT29cell.(P<0.01)Conclusions:VEGF, STAT3and IGF-1R play an important role in colorectal carcinogenesis.VEGF was related to prognosis of colorectal carcinoma. SiRNA silencing VEGF gene can suppress the proliferation of colorectal cancer cells and induce apoptosis to a certain degree. The application of RNA interference technology is expected to become an effective gene therapy approach to colorectal cancer. VEGF may be a effictive gene therapy target of colorectal cancer.