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Expression of integrin α v β 3 correlates with activation of membrane‐type matrix metalloproteinase‐1 (MT1‐MMP) and matrix metalloproteinase‐2 (MMP‐2) in human melanoma cells in vitro and in vivo
Author(s) -
Hofmann Uta B.,
Westphal Johan R.,
Van Kraats Annemieke A.,
Ruiter Dirk J.,
Van Muijen Goos N.P.
Publication year - 2000
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/1097-0215(20000701)87:1<12::aid-ijc3>3.0.co;2-a
Subject(s) - matrix metalloproteinase , integrin , cell culture , beta (programming language) , microbiology and biotechnology , cell , biology , chemistry , biochemistry , genetics , computer science , programming language
Activation of matrix metalloproteinase‐2 (MMP‐2) is mediated by binding to the complex of membrane‐type matrix metalloproteinase‐1 (MT1‐MMP) with tissue inhibitor of MMP‐2 (TIMP‐2) on the cell surface. Binding of MMP‐2 to integrin α v β 3 has been implicated in presenting activated MMP‐2 on the cell surface of invasive cells, but interactions with the MT1‐MMP‐TIMP‐2 system have not been considered. Therefore, we studied the expression and interaction of MT1‐MMP, MMP‐2 and TIMP‐2 in the α v β 3 ‐negative melanoma cell line BLM and in its β 3 ‐transfected, α v β 3 ‐expressing counterpart BLM‐β 3 , both on cell lines and in xenografts. Total expression levels of MMP‐2, MT1‐MMP and TIMP‐2 did not differ markedly between the α v β 3 ‐negative and α v β 3 ‐positive cells. Remarkable differences, however, exist in the presence of active MMP‐2 and MT1‐MMP. Zymography on cell lysates revealed that active MMP‐2 was restricted to α v β 3 ‐positive cell line and clearly accumulated in xenografts derived from the BLM‐β 3 cells, confirming the relevance of this integrin for MMP‐2 function. Western blotting of cell lysates showed that processing of proMT1‐MMP to the activated form was enhanced in BLM‐β 3 . The ratio of active and inactive MT1‐MMP was 3‐fold higher in the β 3 ‐transfectants. Immunofluorescence double‐labeling followed by confocal laser microscopy showed co‐localization of MT1‐MMP and α v β 3 on BLM‐β 3 cells. In xenografts from BLM‐β 3 cells, active MT1‐MMP was markedly increased. Our results demonstrate that expression of α v β 3 in cell lines and xenografts was accompanied by an accumulation of active MT1‐MMP and MMP‐2. Furthermore, MT1‐MMP and α v β 3 are co‐localized on the cell membrane of tumor cells. These findings suggest that activated MT1‐MMP co‐localized with α v β 3 may be involved in activation of α v β 3 ‐bound MMP‐2. Int. J. Cancer 87:12–19, 2000. © 2000 Wiley‐Liss, Inc.