TIMP-1 induces an EMT-like phenotypic conversion in MDCK cells independent of its MMP-inhibitory domain.
Matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs) regulate epithelial-mesenchymal transition (EMT) critical for the development of epithelial organs as well as cancer cell invasion. TIMP-1 is frequently overexpressed in several types of human cancers and serves as a prognostic marker. The present study investigates the roles of TIMP-1 on the EMT process and formation of the lumen-like structure in a 3D Matrigel culture of MDCK cells. We show that TIMP-1 overexpression effectively prevents cell polarization and acinar-like structure formation. TIMP-1 induces expression of the developmental EMT transcription factors such as SLUG, TWIST, ZEB1 and ZEB2, leading to downregulation of epithelial marker and upregulation of mesenchymal markers. Importantly, TIMP-1's ability to induce the EMT-like process is independent of its MMP-inhibitory domain. To our surprise, TIMP-1 induces migratory and invasive properties in MDCK cells. Here, we present a novel finding that TIMP-1 signaling upregulates MT1-MMP and MMP-2 expression, and potentiates MT1-MMP activation of pro-MMP-2, contributing to tumor cell invasion. In spite of the fact that TIMP-1, as opposed to TIMP-2, does not interact with and inhibit MT1-MMP, TIMP-1 may act as a key regulator of MT1-MMP/MMP-2 axis. Collectively, our findings suggest a model in which TIMP-1 functions as a signaling molecule and also as an endogenous inhibitor of MMPs. This concept represents a paradigm shift in the current view of TIMP-1/MT1-MMP interactions and functions during cancer development/progression.
Department of Pathology, Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan, United States of America.
Young Suk
YS
Jung
Xu-Wen
XW
Liu
Rosemarie
R
Chirco
Richard B
RB
Warner
Rafael
R
Fridman
Hyeong-Reh Choi
HR
Kim
D000818:Animals; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology; D016764:Cell Polarity / Q000502:physiology; D049109:Cell Proliferation; D017931:DNA Primers / Q000235:genetics; D004285:Dogs; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology*; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000502:physiology*; D055785:Gene Knockdown Techniques; D015151:Immunoblotting; D053511:Matrix Metalloproteinase 14 / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013778:Tetrazolium Salts; D013844:Thiazoles; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
D017931:DNA Primers; D013778:Tetrazolium Salts; D013844:Thiazoles; D019715:Tissue Inhibitor of Metalloproteinase-1; D014157:Transcription Factors; D020778:Matrix Metalloproteinase 2; D053511:Matrix Metalloproteinase 14; C022616:thiazolyl blue