Attachment, proliferation, and motility of RBE cells on extracellular matrix proteins. (A) Cell attachment; Serum-starved wild type (wt; □) or CEACAM1-L–expressing (CEACAM1-L; ▦) cells (3 × 10⁴) were plated on fibronectin (FN), laminin-1 (LN), or Matrigel coatings under serum-free conditions for 75 minutes. Nonadherent cells were removed by washing, and adherent cells were fixed and visualized with crystal violet. Quantification of attachment after 75 minutes was measured at 570 nm after dye release. The data represent means ± SD of 3 independent experiments done in triplicate. (B) Cell proliferation. Serum-starved wt (□) or CEACAM1-L–expressing (▦) cells (2 × 10⁴) were plated on matrix protein–coated 96-well plates in medium containing 1% FCS and BrdU for 24 hours. Incorporation of BrdU was measured at 405 nm as described in “Materials and methods.” The results are shown as means ± SD of 2 independent experiments done in triplicate. (Ci) Representative paths of cell migration on plastic, fibronectin (FN), or laminin-1 (LN) of RBE wt (wt) or CEACAM1-L–expressing cells (CEACAM1-L) tracked at 20-minute intervals over a span of 8 hours. (ii) Quantification of cell migration represented as means ± SD in duplicate assays. ^*P < .001.