title: Membrane-type 1 matrix metalloproteinase expression is regulated by zonula occludens-1 in human breast cancer cells.
abstract: The acquisition of a migratory/invasive phenotype by tumor cells is characterized by the loss of cell-cell adhesion contacts and the expression of degradative properties. In this study, we examined the effect of the disorganization of occludin/zonula occludens (ZO)-1 tight junction (TJ) complexes on the expression of membrane-type 1 matrix metalloproteinase (MT1-MMP). We first compared the expression of MT1-MMP and the localization of occludin/ZO-1 complexes in breast tumor cell lines displaying various degrees of invasiveness. We showed that the expression of MT1-MMP in invasive breast tumor cell lines correlates with the absence of occludin and with a cytoplasmic localization of ZO-1. In contrast, noninvasive cell lines displayed a membrane staining for both ZO-1 and occludin and did not express MT1-MMP. In vivo, cytoplasmic ZO-1 and MT1-MMP could be detected in invasive tumor clusters of human breast carcinomas. We then used RNA interference strategy to inhibit ZO-1 expression in invasive BT549 cells and to evaluate the effect of ZO-1 down-regulation on MT1-MMP expression. We observed that ZO-1 small interfering RNA transfection down-regulates MT1-MMP mRNAs and proteins and subsequently decreases the ability of tumor cells to invade a reconstituted basement membrane in a Boyden chamber assay. Inversely, transfection of expression vectors encoding wild-type ZO-1 or the NH2-terminal fragment of ZO-1 comprising the PSD95/DLG/ZO-1 domains in BT549 activated a human MT1-MMP promoter luciferase reporter construct and increased cell invasiveness. Such transfections concomitantly activated the beta-catenin/TCF/LEF pathway. Our results therefore show that ZO-1, besides its structural role in TJ assembly, can intervene in signaling events promoting tumor cell invasion.
authors.affiliation: Institut National de la Sante et de la Recherche Medicale UMRS 514, Laboratory of Histology, IFR 53, CHU Maison Blanche, Reims, France. myriam.polette@univ-reims.fr
authors.forename: Myriam
authors.initials: M
authors.lastname: Polette
authors.forename: Christine
authors.initials: C
authors.lastname: Gilles
authors.forename: Béatrice
authors.initials: B
authors.lastname: Nawrocki-Raby
authors.forename: Jouko
authors.initials: J
authors.lastname: Lohi
authors.forename: Walter
authors.initials: W
authors.lastname: Hunziker
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Foidart
authors.forename: Philippe
authors.initials: P
authors.lastname: Birembaut
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics; D003593:Cytoplasm / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D015536:Down-Regulation; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D053504:Matrix Metalloproteinases, Membrane-Associated; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008666:Metalloendopeptidases / Q000096:biosynthesis* / Q000235:genetics; D009361:Neoplasm Invasiveness; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics; D015533:Transcriptional Activation; D014162:Transfection; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin
chemical_list: C495270:CTNNB1 protein, human; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D008565:Membrane Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C569042:TJP1 protein, human; D015534:Trans-Activators; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases