Effect of SDF-1 on CRC cell adhesion to HUVECs. All bar graphs represent the multiple increases over the control cells (CL), calculated as the mean ± standard error of the mean (SEM) from five experiments. DLD-1 cells were kept as CL or stimulated with SDF-1 for 4 h. *P < 0.05 versus CL. #P < 0.05 versus vehicle control (DMSO) or IgG-treated cells with SDF-1 stimulation. (A) DLD-1 and SW48 cells treated with different doses of SDF-1 were labeled with DiI and added to confluent monolayers of HUVECs for 1 h. (B) Before being kept as CL or stimulated with SDF-1, DLD-1 and SW48 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. (D) Flow cytometry shows the cell surface expression of CXCR4. DLD-1 cells were kept as CL or stimulated with SDF-1. Cells were incubated with mAb against CXCR4 or isotype-matched IgG served as a blank.