title: The high affinity alphaIIb beta3 integrin is involved in invasion of human melanoma cells.
abstract: Integrins play an important role in mediating tumor cell-extracellular matrix (ECM) and tumor cell-endothelial cell interactions. The integrin alphaIIb beta3 (GPIIb-IIIa) is expressed on the surface of platelets in an inactive state and requires a conformational change to recognize extracellular matrix proteins such as fibrinogen, fibronectin, vitronectin, and others. In this study, we questioned whether human melanoma cells express the alphaIIb beta3 integrin. Reverse transcription-PCR/Southern blotting, Northern blotting, and dot blotting demonstrated the presence of the platelet-type alphaIIb beta3 integrin in human melanoma WM 983B, WM 983A, and WM 35 cells. AP-2, a monoclonal antibody (mAb) to alphaIIb beta3, positively stained two human melanoma specimens, indicating expression of this integrin in vivo. Phorbol 12-myristate 13-acetate and 12(S)-hydroxyeicosatetraenoic acid, two activators of protein kinase C, stimulated adhesion of melanoma cells to immobilized fibronectin and PAC-1, a mAb to alphaIIb beta3. PAC-1 specifically recognizes the conformationally active form of platelet alphaIIb beta3. Phorbol 12-myristate 13-acetate-stimulated adhesion of WM 983B cells to PAC-1 was completely blocked by an RGD peptide, thus providing evidence that tumor cell adhesion to PAC-1 is mediated via the alphaIIb beta3 integrin but not the Fc receptor. Confocal immunofluorescent studies demonstrated that fibronectin-adherent melanoma cells possess an intracellularly localized pool of high-affinity alphaIIb beta3. Invasion of WM 983B cells through fibronectin was stimulated by 12(S)-hydroxyeicosatetraenoic acid, and this stimulated invasion was blocked by the mAb PAC-1. The data suggest that melanoma cells express the high-affinity alphaIIb beta3 integrin, which is involved in tumor invasion.
authors.affiliation: Department of Radiation Oncology, Wayne State University, Detroit, Michigan 48202, USA.
authors.forename: M
authors.initials: M
authors.lastname: Trikha
authors.forename: J
authors.initials: J
authors.lastname: Timar
authors.forename: S K
authors.initials: SK
authors.lastname: Lundy
authors.forename: K
authors.initials: K
authors.lastname: Szekeres
authors.forename: Y
authors.initials: Y
authors.lastname: Cai
authors.forename: A T
authors.initials: AT
authors.lastname: Porter
authors.forename: K V
authors.initials: KV
authors.lastname: Honn
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000494:pharmacology; D000328:Adult; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015152:Blotting, Northern; D015139:Blotting, Southern; D002448:Cell Adhesion / Q000187:drug effects; D000939:Epitopes / Q000378:metabolism; D005260:Female; D005353:Fibronectins / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007150:Immunohistochemistry; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D018613:Microscopy, Confocal; D009361:Neoplasm Invasiveness; D009842:Oligopeptides / Q000494:pharmacology; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D005353:Fibronectins; D009842:Oligopeptides; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D012333:RNA, Messenger; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; C047981:arginyl-glycyl-aspartic acid; D013755:Tetradecanoylphorbol Acetate