Adhesion to carcinoembryonic antigen by human colorectal carcinoma cells involves at least two epitopes

✍ Scribed by J. M. Jessup; J. C. Kim; P. Thomas; S. Ishii; R. Ford; J. E. Shively; H. Durbin; C. P. Stanners; A. Fuks; H. Zhou; H. J. Hansen; D. M. Goldenberg; G. Steele Jr

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: French
• Weight: 872 KB
• Volume: 55
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910550216

✦ Synopsis

Carcinoembryonic antigen (CEA) may be involved in both cell-cell and cell-substrate adhesion. Our purpose was to determine whether epitopes involved in the homophilic binding of human colorectal carcinoma cells to CEA participated in adhesion to basement membrane proteins. Three human colorectal adenocarcinoma cell lines and one CHO cell line transfected with CEA cDNA were tested in a solid-phase adhesion assay. The 2 CEA-expressing carcinoma cell lines (KM-I2c and CCL 188) and the transfectant, but not the parental CHO line, bound to CEA, The CEA-non-producing carcinoma line (Clone A) did not bind to CEA. All colorectal carcinoma cell lines, the transfectant and the parental CHO line bound to laminin, while the colorectal carcinoma lines bound to type-IV collagen. MAbs to epitopes on CEA that cross-react with non-specific crossreacting antigen (NCA) inhibited adhesion of CEA-expressing cells to CEA. MAbs to non-cross-reactive epitopes of CEA did not block adhesion to CEA. When the inhibitory anti-CEA antibodies were compared in a competitive radioimmunoassay, 2 distinct epitopes were identified. Epitope I is in the N-terminal domain and defined by MAbs MN3, T84.1 and C I 10, whereas epitope II is located in the repeating loop domains and is recognized by antibodies M N 15, PR3B 10 and NP I. None of the antibodies to epitope I or II blocked adhesion by KM-I2c or CCL I88 cells to laminin or type-IV collagen. Thus, at least 2 different regions on CEA participate in adhesion to CEA but not to collagen or laminin by CEA-expressing human colorectal carcinoma cells.