title: Claudin-6 enhances cell invasiveness through claudin-1 in AGS human adenocarcinoma gastric cancer cells.
abstract: Claudins participate in tissue barrier function. The loss of this barrier is associated to metalloproteases-related extracellular matrix and basal membranes degradation. Claudin-1 is a pro-MMP-2 activator and claudin-6 transfected AGS (AGS-Cld6) cells are highly invasive. Our aim was to determine if claudin-6 was direct or indirectly associated with MMP-2 activation and cell invasiveness. Cytofluorometry, cell fractioning, immunoprecipitation, gelatin-zymography, cell migration and invasiveness assays were performed, claudin-2, -6, -7 and -9 transfected AGS cells, anti-MMP-2, -9 and -14, anti-claudins specific antibodies and claudin-1 small interfering RNA were used. The results showed a significant (p<0.001) overexpression of claudin-1 in AGS-Cld6 cell membranes. A strong MMP-2 activity was identified in culture supernatants of AGS-Cld6. Claudin-1 co-localized with MMP-2 and MMP-14; interestingly a significant increase in cell membrane and cytosol MMP-14 expression was detected in AGS-Cld6 cells (p<0.05). Silencing of claudin-1 in AGS-Cld6 cells showed a 60% MMP-2 activity decrease in culture supernatants and a significant decrease (p<0.05) in cell migration and invasiveness. Our results suggest that claudin-6 induces MMP-2 activation through claudin-1 membrane expression, which in turn promotes cell migration and invasiveness.
authors.affiliation: Laboratorio de Inmunobiología, Departmento de Biología Celular y Tisular, Facultad de Medicina, UNAM, Circuito Interior s/n, Ciudad Universitaria, México D.F. 04510, Mexico.
authors.forename: A C
authors.initials: AC
authors.lastname: Torres-Martínez
authors.affiliation: Laboratorio de Inmunobiología, Departmento de Biología Celular y Tisular, Facultad de Medicina, UNAM, Circuito Interior s/n, Ciudad Universitaria, México D.F. 04510, Mexico.
authors.forename: J F
authors.initials: JF
authors.lastname: Gallardo-Vera
authors.affiliation: Laboratorio de Inmunobiología, Departmento de Biología Celular y Tisular, Facultad de Medicina, UNAM, Circuito Interior s/n, Ciudad Universitaria, México D.F. 04510, Mexico.
authors.forename: A N
authors.initials: AN
authors.lastname: Lara-Holguin
authors.affiliation: Laboratorio de Inmunobiología, Departmento de Biología Celular y Tisular, Facultad de Medicina, UNAM, Circuito Interior s/n, Ciudad Universitaria, México D.F. 04510, Mexico.
authors.forename: L F
authors.initials: LF
authors.lastname: Montaño
authors.affiliation: Laboratorio de Inmunobiología, Departmento de Biología Celular y Tisular, Facultad de Medicina, UNAM, Circuito Interior s/n, Ciudad Universitaria, México D.F. 04510, Mexico. Electronic address: erendon@unam.mx.
authors.forename: E P
authors.initials: EP
authors.lastname: Rendón-Huerta
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology*; D062445:Claudin-1 / Q000378:metabolism*; D057167:Claudins / Q000378:metabolism*; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D009361:Neoplasm Invasiveness; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D019108:Tight Junctions / Q000378:metabolism
chemical_list: D062445:Claudin-1; D057167:Claudins; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9; C122101:claudin 6
keywords: Claudin; Cldn-1; Cldn-6; MMP-14; MMP-2