title: Role of manganese in MG-63 osteosarcoma cell attachment to fibrinogen and von Willebrand factor.
abstract: Some integrin receptors have been reported to be functionally distinct in different cell types. In endothelial and melanoma cells, the vitronectin receptor, alpha v beta 3 binds fibrinogen (fg) and von Willebrand factor (vWf) in addition to vitronectin itself, whereas it fails to do so in MG-63 osteosarcoma cells. In this report, it is shown that, in the presence of Mn2+, MG-63 cells attach more efficiently to vitronectin and acquire the de novo capacity to adhere to fg- and vWf-coated surfaces. The latter phenomenon occurs with full cell spreading, F-actin microfilament organization, and alpha v and beta 3 clustering at focal contacts. In contrast, beta 1 and beta 5 do not localize to adhesion plaques under the same experimental conditions. An antiserum to the beta 3 chain and a synthetic peptide containing the sequence Gly-Arg-Gly-Asp-Ser-Pro block MG-63 attachment to fg and vWf in the presence of Mn2+. The minimal active concentration of Mn2+ is in the range of 0.1 to 1 microns. These data suggest that the acquired capacity of MG-63 to attach to fg and vWf in the presence of Mn2+ is mediated by alpha v beta 3 and that differences in alpha v beta 3 receptor specificity may be modulated by exogenous factors.
authors.affiliation: Instituto di Ricerche Farmacologiche Mario Negri, Milano, Italy.
authors.forename: M G
authors.initials: MG
authors.lastname: Lampugnani
authors.forename: S
authors.initials: S
authors.lastname: Bernasconi
authors.forename: P
authors.initials: P
authors.lastname: Neri
authors.forename: L
authors.initials: L
authors.lastname: Lozzi
authors.forename: I
authors.initials: I
authors.lastname: Gavazzi
authors.forename: P C
authors.initials: PC
authors.lastname: Marchisio
authors.forename: E
authors.initials: E
authors.lastname: Dejana
mesh_terms: D000595:Amino Acid Sequence; D002413:Cations, Divalent; D002448:Cell Adhesion; D005340:Fibrinogen / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D066298:In Vitro Techniques; D016023:Integrins / Q000378:metabolism; D008345:Manganese / Q000502:physiology*; D008969:Molecular Sequence Data; D008985:Monensin / Q000494:pharmacology; D009842:Oligopeptides; D012516:Osteosarcoma / Q000473:pathology*; D010455:Peptides / Q000378:metabolism; D011971:Receptors, Immunologic / Q000378:metabolism; D019030:Receptors, Vitronectin; D014407:Tumor Cells, Cultured; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D002413:Cations, Divalent; D005353:Fibronectins; D016023:Integrins; D009842:Oligopeptides; D010455:Peptides; D011971:Receptors, Immunologic; D019030:Receptors, Vitronectin; D014841:von Willebrand Factor; D008345:Manganese; C047981:arginyl-glycyl-aspartic acid; D005340:Fibrinogen; D008985:Monensin