Carcinoembryonic antigen functions as an accessory adhesion molecule mediating colon epithelial cell-collagen interactions.
We have previously shown that a human colon carcinoma cell line (SW1222) expresses a collagen receptor recognizing the Arg-Gly-Asp tripeptide sequence found in collagen. This receptor mediates the cellular attachment to collagen and, subsequently, the glandular differentiation seen in a three-dimensional collagen gel culture. In a search to identify cell surface molecules mediating the adhesion and differentiation of SW1222 cells, we have screened a panel of monoclonal antibodies recognizing epithelial cell surface determinants for their ability to inhibit the collagen binding of SW1222 cells. We have found that four monoclonal antibodies recognizing the 180-kDa carcinoembryonic antigen (CEA) glycoprotein and other members of the CEA family inhibited (up to 87%) the binding of SW1222 cells to type I collagen matrix. Using a cell attachment assay, we have not detected any direct collagen binding of either purified CEA or another CEA-expressing human colon carcinoma cell line (LS174T). These data suggest that CEA is not a collagen-binding protein itself but is likely to be associated with the functional Arg-Gly-Asp collagen receptor expressed by SW1222 cells. We suggest that CEA may function as an accessory molecule, controlling the functional activity of the SW1222 collagen receptor.
Pignatelli
M
M
Imperial Cancer Research Fund, London, United Kingdom.
Durbin
H
H
Bodmer
W F
WF
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000276:immunology; D002272:Carcinoembryonic Antigen; D002448:Cell Adhesion; D002460:Cell Line; D003094:Collagen / Q000378:metabolism; D003110:Colonic Neoplasms; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis / Q000494:pharmacology; D011485:Protein Binding; D014407:Tumor Cells, Cultured / Q000276:immunology / Q000502:physiology*
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D002272:Carcinoembryonic Antigen; D009842:Oligopeptides; D003094:Collagen