Effect of CXCL12 on the adhesive and invasive properties of hu/SCID tumor cells. (A) Effect of CXCL12 on adhesion of hu/SCID tumor cells to fibronectin and endothelial cells. The panels from left to right represent adhesion of hu/SCID tumor cells to bovine serum albumin (BSA), fibronectin, and HUVECs. Unstimulated cells are shown as black bars; open and gray bars represent hu/SCID tumor cells stimulated with CXCL12/SDF-1α (200 ng/mL) in the absence and in the presence, respectively, of the CXCR4 antagonist TC14012. Data are shown as mean ± SEM of 2 consecutive experiments; the single asterisk denotes a significant difference compared with untreated cells (P < .05); 2 asterisks denote a significant inhibition by TC14012 of the adhesive properties of CXCL12-stimulated cells (P < .05). (B) Cells invading the Matrigel were collected from the lower compartments and counted as detailed in “Materials and methods”; results are expressed as number of cells per high power field (HPF) and represent mean values ± SEM of 3 replicate determinations for each tumor. Hu/SCID lymphoma cells showed significant invasion through Matrigel toward a CXCL12 gradient (open columns); this phenomenon was inhibited by treating the cells with TC14012 (gray columns). The single asterisk denotes a significant difference (P < .05) compared with unstimulated cells; 2 asterisks denote a significant inhibition by TC14012 of the invasive properties of CXCL12-stimulated cells (P < .05). Results obtained in 3 different hu/SCID tumor masses representative of 4 consecutive experiments are shown.