title: Platelet-endothelial cell adhesion molecule-1 (CD31) recycles and induces cell growth inhibition on human tumor cell lines.
abstract: CD31 (PECAM-1) is a 130-kDa member of the immunoglobulin gene superfamily expressed on endothelial cells, platelets, and most leukocytes. This report demonstrates by Western Blot and immunofluorescence that some human melanoma and adenocarcinoma cell lines express CD31 on the cell surface. The surface expression of CD31 was regulated by cell-cell contact, being higher on sparse and spontaneously detached cells. Indeed, fixing and permeabilizing tumor cells revealed a cytoplasmic pool, which was confirmed by confocal microscopy. Some of the plasma surface molecule is endocytosed following mAb binding. Engagement of CD31 on tumor cells via domain-3 inhibited proliferation by inducing cell apoptosis. On the other hand, apoptosis does not increase CD31 expression. Overall, these results indicate that there is an intracellular pool of CD31 on some tumor cells, which modulates CD31 surface expression and its role in cancer cell growth and metastasis. Thus, the expression of CD31 and its role in cell survival in some tumor cells appears to differ from endothelial cells.
authors.affiliation: Laboratorio de Inmunogenética, Hospital de Clínicas José de San Martín, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Viviana P
authors.initials: VP
authors.lastname: Lutzky
authors.forename: Romina P
authors.initials: RP
authors.lastname: Carnevale
authors.forename: Mariano J
authors.initials: MJ
authors.lastname: Alvarez
authors.forename: Paulo C
authors.initials: PC
authors.lastname: Maffia
authors.forename: Sandra I
authors.initials: SI
authors.lastname: Zittermann
authors.forename: Osvaldo L
authors.initials: OL
authors.lastname: Podhajcer
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Issekutz
authors.forename: H Eduardo
authors.initials: HE
authors.lastname: Chuluyan
mesh_terms: D017304:Annexin A5 / Q000378:metabolism; D000906:Antibodies / Q000276:immunology; D002450:Cell Communication; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D016895:Culture Media, Serum-Free; D006801:Humans; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology*; D016376:Oligonucleotides, Antisense / Q000235:genetics; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D017304:Annexin A5; D000906:Antibodies; D016895:Culture Media, Serum-Free; D016376:Oligonucleotides, Antisense; D019408:Platelet Endothelial Cell Adhesion Molecule-1