title: LFA-1 and ICAM-1 expression induced during melanoma-endothelial cell co-culture favors the transendothelial migration of melanoma cell lines in vitro.
abstract: BACKGROUND
  Patients with metastatic melanoma have a poor median rate of survival. It is therefore necessary to increase our knowledge about melanoma cell dissemination which includes extravasation, where cancer cells cross the endothelial barrier. Extravasation is well understood during travelling of white blood cells, and involves integrins such as LFA-1 (composed of two chains, CD11a and CD18) expressed by T cells, while ICAM-1 is induced during inflammation by endothelial cells. Although melanoma cell lines cross endothelial cell barriers, they do not express LFA-1. We therefore hypothesized that melanoma-endothelial cell co-culture might induce the LFA-1/ICAM ligand/receptor couple during melanoma transmigration.
  
  
  METHODS
  A transwell approach has been used as well as blocking antibodies against CD11a, CD18 and ICAM-1. Data were analyzed with an epifluorescence microscope. Fluorescence intensity was quantified with the ImageJ software.
  
  
  RESULTS
  We show here that HUVEC-conditioned medium induce cell-surface expression of LFA-1 on melanoma cell lines. Similarly melanoma-conditioned medium activates ICAM-1 expression in endothelial cells. Accordingly blocking antibodies of ICAM-1, CD11a or CD18 strongly decrease melanoma transmigration. We therefore demonstrate that melanoma cells can cross endothelial monolayers in vitro due to the induction of ICAM-1 and LFA-1 occurring during the co-culture of melanoma and endothelial cells. Our data further suggest a role of LFA-1 and ICAM-1 in the formation of melanoma cell clumps enhancing tumor cell transmigration.
  
  
  CONCLUSIONS
  Melanoma-endothelial cell co-culture induces LFA-1 and ICAM-1 expression, thereby favoring in vitro melanoma trans-migration.
authors.affiliation: Team Regulation des Reponses Immunitaires, Institut Jacques Monod, CNRS, UMR 7592, Univ Paris Diderot, Sorbonne Paris Cité, Paris, F-75205, France.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Ghislin
authors.forename: Dorian
authors.initials: D
authors.lastname: Obino
authors.forename: Sandrine
authors.initials: S
authors.lastname: Middendorp
authors.forename: Nicole
authors.initials: N
authors.lastname: Boggetto
authors.forename: Catherine
authors.initials: C
authors.lastname: Alcaide-Loridan
authors.forename: Frederique
authors.initials: F
authors.lastname: Deshayes
mesh_terms: D040881:CD11a Antigen / Q000096:biosynthesis; D018821:CD18 Antigens / Q000096:biosynthesis; D002450:Cell Communication / Q000502:physiology*; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D016169:Lymphocyte Function-Associated Antigen-1 / Q000096:biosynthesis* / Q000378:metabolism; D008545:Melanoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008856:Microscopy, Fluorescence; D016133:Polymerase Chain Reaction; D057705:Transendothelial and Transepithelial Migration / Q000502:physiology*; D014407:Tumor Cells, Cultured
chemical_list: D040881:CD11a Antigen; D018821:CD18 Antigens; D016207:Cytokines; D016169:Lymphocyte Function-Associated Antigen-1; D018799:Intercellular Adhesion Molecule-1