title: Episialin (MUC1) overexpression inhibits integrin-mediated cell adhesion to extracellular matrix components.
abstract: Episialin (MUC1) is a transmembrane molecule with a large mucin-like extracellular domain protruding high above the cell surface. The molecule is located at the apical side of most glandular epithelial cells, whereas in carcinoma cells it is often present at the entire surface and it is frequently expressed in abnormally large quantities. We have previously shown that overexpression of episialin reduces cell-cell interactions. Here we show that the integrin-mediated adhesion to extracellular matrix of transfectants of a melanoma cell line (A375), a transformed epithelial cell line (MDCK-ras-e) and a human breast epithelial cell line (HBL-100) is reduced by high levels of episialin. This reduction can be reversed by inducing high avidity of the beta 1 integrins by mAb TS2/16 (at least for beta 1-mediated adhesion). The adhesion can also be restored by redistribution of episialin on the cell surface by monoclonal antibodies into patches or caps. Similarly, capping of episialin on ZR-75-1 breast carcinoma cells, growing in suspension, caused adherence and spreading of these cells. We propose that there is a delicate balance between adhesion and anti-adhesion forces in episialin expressing cells, which can be shifted towards adhesion by strengthening the integrin-mediated adhesion, or towards anti-adhesion by increasing the level of expression of episialin.
authors.affiliation: Division of Tumor Biology, The Netherlands Cancer Institute (Antoni van Leeuwenhoekhuis), Amsterdam.
authors.forename: J
authors.initials: J
authors.lastname: Wesseling
authors.forename: S W
authors.initials: SW
authors.lastname: van der Valk
authors.forename: H L
authors.initials: HL
authors.lastname: Vos
authors.forename: A
authors.initials: A
authors.lastname: Sonnenberg
authors.forename: J
authors.initials: J
authors.lastname: Hilkens
mesh_terms: D000818:Animals; D001483:Base Sequence; D001940:Breast; D001943:Breast Neoplasms; D002448:Cell Adhesion; D002455:Cell Division; D002460:Cell Line; D002461:Cell Line, Transformed; D017931:DNA Primers; D004285:Dogs; D016326:Extracellular Matrix Proteins; D005260:Female; D011905:Genes, ras; D006801:Humans; D016023:Integrins / Q000502:physiology*; D007668:Kidney; D008545:Melanoma; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D018396:Mucin-1; D009077:Mucins / Q000096:biosynthesis*; D009363:Neoplasm Proteins / Q000096:biosynthesis; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000096:biosynthesis; D017384:Sequence Deletion; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D017931:DNA Primers; D016326:Extracellular Matrix Proteins; D016023:Integrins; D008562:Membrane Glycoproteins; D018396:Mucin-1; D009077:Mucins; D009363:Neoplasm Proteins; D011994:Recombinant Proteins