silencing of CXCR7 inhibits CXCL12 induced enhancement on SMMC-7721 cells invasion in vitro. A. SMMC-7721 cells were examined for their invasive ability after stimulation with different concentrations of CXCL12 (0, 10 or 100 ng/ml). Representative pictures are shown. B. mean number of invasive cells from each group. Data are expressed as means ± SD. *p < 0.05 (as compared with untreated cells). C. CXCR7shRNA transfected, NC and control cells were treated with CXCL12 (100 ng/ml). The invasive ability of CXCR7shRNA transfected cells appeared significantly reduced, compared with control cells and NC cells. The pictures highlight the differences in number between the CXCR7shRNA transfected, control and NC cells able to invade through Matrigel. D. mean number of invasive cells from five independent fields/well is indicated. Data are expressed as means ± SD from three independent experiments. *p < 0.05 (as compared with control cells).