Effect of SDF-1 on ICAM-1 expression and cell adhesion of CRC cells. (A) SDF-1-stimulated DLD-1 and SW48 cells were treated with isotype-matched IgG or 20 μg/mL neutralizing antibody against ICAM-1, or were transfected with control siRNA (si-CL) or si-ICAM-1, and were then added to HUVECs for 1 h. (B) DLD-1 and SW48 cells were kept as CL or stimulated with SDF-1 for 4 h. Before being kept as CL or stimulated with SDF-1, cells were pretreated with AMD3100 or incubated with neutralizing antibody against CXCR4 for 1 h. (C) Before being kept as CL, DLD-1 cells were pretreated with AMD3100 for 1 h, and were then stimulated with different doses of SDF-1 for 4 h. All bar graphs represent multiple increases of CL cells normalized to 18S rRNA. *p < 0.05 versus CL. #p < 0.05 versus IgG-treated, DMSO-treated, or si-CL-transfected cells. (D) The ICAM-1 basal expression level of DLD-1 cells was analyzed by flow cytometry. Cells were incubated with mAb against ICAM-1 or isotype-matched IgG served as a blank.