Effect of Osteopontin Silencing by Lentivirus-mediated Delivery of RNA Interference on the Growth of U251 Cells in vivo

To observe the effect of osteopontin(OPN) silencing on the growth of human glioma U251 cells of nude mice in vivo and to investigate the mechanism of OPN gene on the proliferation and invasion of glioma U251 cell.LV-N-OPN/U251 cells transfected with blank lentivirus vector,LV-OPNshRNA/U251cells transfected with shRNA lentivirus vector osteopontin,and untransfected U251 cells were injected into the oxter of the nude mice,respectively to establish the xenograft.The excised tumor masses on the 21st day,the volume and the weight of tumors were checked.Histopathological changes were observed.The mRNA and protein expression of OPN,urokinase type plasminogen activator(uPA),matrix metalloproteinase(MMP-2 and MMP-9) were measured by RT-PCR and immunoblotting.The microvessel density(MVD) and vascular endothelial growth factor(VEGF)were detected by immunohistochemistry.OPN interference RNA inhibited OPN expression,cell proliferation and invasion,both volume and weight of tumor were decreased obviously.In addition,the expression of uPA,MMP-2 and MMP-9 were significantly decreased,the expression of MVD and VEGF were also significantly lower.The results indicated that OPN might increase the abilities of invasion of glioma by degrade extracellular matrix to activate uPA,MMP-2,MMP-9 and to promote angiogenesis of tumor.