title: Regulatory role of tetraspanin CD9 in tumor-endothelial cell interaction during transendothelial invasion of melanoma cells.
abstract: Heterotypic interaction among tumor cells (TCs) and endothelial cells (ECs) may play a critical role during the vascular dissemination of neoplastic cells and during pathologic angiogenesis in tumors. To identify molecules involved in these processes, the distribution of vascular junctional proteins was first studied by immunofluorescence at sites of heterologous intercellular contact using TC-EC mosaic monolayers grown on 2-dimensional collagen. Several members of the tetraspanin superfamily, including CD9, CD81, and CD151, were found to localize at the TC-EC contact area. The localization of tetraspanins to the TC-EC heterologous contact area was also observed during the active transmigration of TCs across EC monolayers grown onto 3-dimensional collagen matrices. Dynamic studies by time-lapse immunofluorescence confocal microscopy showed an active redistribution of endothelial CD9 to points of melanoma insertion. Anti-CD9 monoclonal antibodies were found to specifically inhibit the transendothelial migration of melanoma cells; the inhibitory effect was likely caused by a strengthening of CD9-mediated heterotypic interactions of TCs to the EC monolayer. These data support a novel mechanism of tetraspanin-mediated regulation of TC transcellular migration independent of TC motility and growth during metastasis and a role for these molecules in the formation of TC-EC mosaic monolayers during tumor angiogenesis.
authors.affiliation: Servicio de Inmunología, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Longo
authors.forename: M
authors.initials: M
authors.lastname: Yáñez-Mó
authors.forename: M
authors.initials: M
authors.lastname: Mittelbrunn
authors.forename: G
authors.initials: G
authors.lastname: de la Rosa
authors.forename: M L
authors.initials: ML
authors.lastname: Muñoz
authors.forename: F
authors.initials: F
authors.lastname: Sánchez-Madrid
authors.forename: P
authors.initials: P
authors.lastname: Sánchez-Mateos
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D002465:Cell Movement; D002478:Cells, Cultured; D018920:Coculture Techniques; D004396:Coloring Agents; D004730:Endothelium, Vascular / Q000473:pathology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D008545:Melanoma / Q000473:pathology*; D008562:Membrane Glycoproteins; D018613:Microscopy, Confocal; D009361:Neoplasm Invasiveness; D009389:Neovascularization, Pathologic; D012835:Silver Nitrate; D060245:Tetraspanin 29; D014162:Transfection; D014407:Tumor Cells, Cultured; D014471:Umbilical Veins
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; C554869:CD9 protein, human; D004396:Coloring Agents; D008562:Membrane Glycoproteins; D060245:Tetraspanin 29; D012835:Silver Nitrate