CEACAM1-L enhances network formation on Matrigel and cell migration after monolayer injury. (Ai) Single-cell suspensions of 3 × 10⁴ RBE/wt (wt), mock-transfected (mock), or CEACAM1-L–expressing (CEACAM1-L) cells were transferred on Matrigel-coated plates. Images were taken at the indicated time points after plating. Original magnification, × 10. (ii) Quantification of network formation. Length of interconnections between cell clusters were measured at 7 hours and 21 hours. Length of interconnections relative to wt cells after 7 hours are represented as means ± SD of 3 experiments done in duplicate. ^*P < .01. (Bi) RBE wild-type (wt), mock-transfected (mock), and CEACAM1-L–expressing (CEACAM1-L) cells were cultured to confluence. Monolayers were scratched with a pipette tip to create a wound, washed with medium, and recultured. Closure of the cell-free area was followed by phase contrast microscopy and photographed at the indicated time points after scratching. CEACAM1-L–expressing RBE cells show single cells migrating into the wounded area (arrow). Original magnification × 25. (ii) The width of the cell-free area was measured at time 0 (scratching) and 18 hours after scratching. Relative closure of the cell-free area is shown in means ± SD (n = 8). ^*P < .01. (C) Immunoblotting of total cell lysates to determine the expression levels of PECAM-1 and VE-cadherin in RBE wt and CEACAM1-L–expressing cells. The data shown are representative of 2 independent experiments.