title: TIMP-1 via TWIST1 induces EMT phenotypes in human breast epithelial cells.
abstract: Tissue inhibitor of metalloproteinase-1 (TIMP-1) regulates intracellular signaling networks for inhibition of apoptosis. Tetraspanin (CD63), a cell surface binding partner for TIMP-1, was previously shown to regulate integrin-mediated survival pathways in the human breast epithelial cell line MCF10A. In the current study, we show that TIMP-1 expression induces phenotypic changes in cell morphology, cell adhesion, cytoskeletal remodeling, and motility, indicative of an epithelial-mesenchymal transition (EMT). This is evidenced by loss of the epithelial cell adhesion molecule E-cadherin with an increase in the mesenchymal markers vimentin, N-cadherin, and fibronectin. Signaling through TIMP-1, but not TIMP-2, induces the expression of TWIST1, an important EMT transcription factor known to suppress E-cadherin transcription, in a CD63-dependent manner. RNAi-mediated knockdown of TWIST1 rescued E-cadherin expression in TIMP-1-overexpressing cells, demonstrating a functional significance of TWIST1 in TIMP-1-mediated EMT. Furthermore, analysis of TIMP-1 structural mutants reveals that TIMP-1 interactions with CD63 that activate cell survival signaling and EMT do not require the matrix metalloproteinase (MMP)-inhibitory domain of TIMP-1. Taken together, these data demonstrate that TIMP-1 binding to CD63 activates intracellular signal transduction pathways, resulting in EMT-like changes in breast epithelial cells, independent of its MMP-inhibitory function.
  
  
  CONCLUSIONS
  TIMP-1's function as an endogenous inhibitor of MMP or as a "cytokine-like" signaling molecule may be a critical determinant for tumor cell behavior.
authors.affiliation: Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan.
authors.forename: Rosemarie Chirco
authors.initials: RC
authors.lastname: D'Angelo
authors.affiliation: Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan.
authors.forename: Xu-Wen
authors.initials: XW
authors.lastname: Liu
authors.affiliation: Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan.
authors.forename: Abdo J
authors.initials: AJ
authors.lastname: Najy
authors.affiliation: Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan.
authors.forename: Young Suk
authors.initials: YS
authors.lastname: Jung
authors.affiliation: Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan.
authors.forename: Joshua
authors.initials: J
authors.lastname: Won
authors.affiliation: Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan.
authors.forename: Karl X
authors.initials: KX
authors.lastname: Chai
authors.affiliation: Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan.
authors.forename: Rafael
authors.initials: R
authors.lastname: Fridman
authors.affiliation: Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan hrckim@med.wayne.edu.
authors.forename: Hyeong-Reh Choi
authors.initials: HR
authors.lastname: Kim
mesh_terms: D017209:Apoptosis / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation / Q000235:genetics; D002470:Cell Survival / Q000235:genetics; D004847:Epithelial Cells; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D060149:Tetraspanin 30; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics* / Q000378:metabolism; D051879:Twist-Related Protein 1 / Q000235:genetics / Q000378:metabolism*
chemical_list: C554586:CD63 protein, human; D015820:Cadherins; D009687:Nuclear Proteins; C560822:TIMP1 protein, human; C103173:TWIST1 protein, human; D060149:Tetraspanin 30; D019715:Tissue Inhibitor of Metalloproteinase-1; D051879:Twist-Related Protein 1