Expression of integrin alpha(v)beta(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

Int J Cancer. 2000 Jul 1;87(1):12-9. doi: 10.1002/1097-0215(20000701)87:1<12::aid-ijc3>;2-a.


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 alpha(v)beta(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 alpha(v)beta(3)-negative melanoma cell line BLM and in its beta(3)-transfected, alpha(v)beta(3)-expressing counterpart BLM-beta(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 alpha(v)beta(3)-negative and alpha(v)beta(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 alpha(v)beta(3)-positive cell line and clearly accumulated in xenografts derived from the BLM-beta(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-beta(3). The ratio of active and inactive MT1-MMP was 3-fold higher in the beta(3)-transfectants. Immunofluorescence double-labeling followed by confocal laser microscopy showed co-localization of MT1-MMP and alpha(v)beta(3) on BLM-beta(3) cells. In xenografts from BLM-beta(3) cells, active MT1-MMP was markedly increased. Our results demonstrate that expression of alpha(v)beta(3) in cell lines and xenografts was accompanied by an accumulation of active MT1-MMP and MMP-2. Furthermore, MT1-MMP and alpha(v)beta(3) are co-localized on the cell membrane of tumor cells. These findings suggest that activated MT1-MMP co-localized with alpha(v)beta(3) may be involved in activation of alpha(v)beta(3)-bound MMP-2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Cell Membrane / metabolism
  • Enzyme Activation
  • Fluorescent Antibody Technique
  • Humans
  • Matrix Metalloproteinase 14
  • Matrix Metalloproteinase 2 / metabolism*
  • Matrix Metalloproteinase 9 / metabolism
  • Matrix Metalloproteinases, Membrane-Associated
  • Melanoma / metabolism*
  • Metalloendopeptidases / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Neoplasm Transplantation
  • RNA, Messenger / metabolism
  • Receptors, Vitronectin / biosynthesis*
  • Receptors, Vitronectin / physiology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tissue Inhibitor of Metalloproteinase-2 / metabolism
  • Transfection
  • Tumor Cells, Cultured


  • Mmp14 protein, mouse
  • RNA, Messenger
  • Receptors, Vitronectin
  • Tissue Inhibitor of Metalloproteinase-2
  • Matrix Metalloproteinases, Membrane-Associated
  • Metalloendopeptidases
  • Matrix Metalloproteinase 2
  • Matrix Metalloproteinase 9
  • Matrix Metalloproteinase 14