Membrane-type 1 matrix metalloproteinase expression is regulated by zonula occludens-1 in human breast cancer cells

Cancer Res. 2005 Sep 1;65(17):7691-8. doi: 10.1158/0008-5472.CAN-04-4230.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Breast Neoplasms / enzymology*
  • Breast Neoplasms / genetics
  • Cytoplasm / metabolism
  • Cytoskeletal Proteins / genetics
  • DNA, Complementary / genetics
  • Down-Regulation
  • Gene Expression Regulation, Enzymologic
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Matrix Metalloproteinases, Membrane-Associated
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Metalloendopeptidases / biosynthesis*
  • Metalloendopeptidases / genetics
  • Neoplasm Invasiveness
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Promoter Regions, Genetic
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • RNA, Small Interfering / genetics
  • Trans-Activators / genetics
  • Transcriptional Activation
  • Transfection
  • Zonula Occludens-1 Protein
  • beta Catenin

Substances

  • CTNNB1 protein, human
  • Cytoskeletal Proteins
  • DNA, Complementary
  • Membrane Proteins
  • Phosphoproteins
  • RNA, Messenger
  • RNA, Small Interfering
  • TJP1 protein, human
  • Trans-Activators
  • Zonula Occludens-1 Protein
  • beta Catenin
  • Matrix Metalloproteinases, Membrane-Associated
  • Metalloendopeptidases