Objective   To observe the effects of CXCR4 downregulation on the invasion capacity and VEGF secretion of glioma stem cells (GSCs).    Methods   Coexpression of CXCR4 and CD133 in U87 cells and their xenografts grown in nude mice brain was detected by indirect immunofluorescence

under a laser scanning microscope. Tumorspheres were isolated from control U87 cells and CXCR4-siRNA U87 cells

respectively. We investigated the expression of CD133

nestin and CXCR4 in tumorspheres by laser scanning microscopy. Effects of CXCR4 downregulation on invasion and VEGF production of GSCs were detected by transwell assay and ELISA respectively.    Results   CXCR4 and CD133 were coexpressed in U87 cells and their xenografts. Downregulation of CXCR4 expression inhibits the invasion capacity [siRNA:（17.0±5.8）

control:（71.5±8.7）

P0.05] and VEGF secretion of GSCs[siRNA: 24 h （690±24）pg/ml，48 h （1 504±53）pg/ml

control: 24 h （850±25）pg/ml，48 h （2 001±150）pg/ml

P0.05].    Conclusion   GSCs express CXCR4

and downregulation of CXCR4 expression attenuates the invasion and pro-angiogenic capacity of GSCs

which suggests that CXCR4 expressed on GSCs may be a potential target of glioma therapy.