Matrix metalloproteinase activity and osteoclasts in experimental prostate cancer bone metastasis tissue

Am J Pathol. 2005 Apr;166(4):1173-86. doi: 10.1016/S0002-9440(10)62337-1.


Previously, we and others showed that broad spectrum pharmaceutical inhibition of matrix metalloproteinase (MMP) activity reduces intraosseous tumor burden and bone degradation in animal models of bone metastasis. Herein, we used specific assays to measure net enzymatic activities of individual MMPs during colonization of bone by prostate cancer cells. PC3 cells were injected into the marrow of human fetal femurs previously implanted in SCID mice. Net MMP-9 activity in bone tissues peaked 2 weeks after injection, coinciding with a wave of osteoclast recruitment. In contrast, MMP-2 and MT1-MMP activity did not change. In vitro, co-culture of PC3 cells with bone tissue led to activation of pro-MMP-9 and increases in secreted net MMP-9 activity. Activation of pro-MMP-9 was prevented by metalloprotease inhibitors but not by inhibitors of other classes of proteases. Ribozyme suppression of MMP-9 expression in PC3 cells did not affect pro-MMP-9 activation or net MMP-9 activity and did not affect the phenotype of bone tumors. siRNA targeting of MMP-9 expression in preosteoclasts in vitro demonstrated that tumor-induced preosteoclast motility was dependent on MMP-9 expression. These data suggest that osteoclast-derived MMP-9 may represent a potential therapeutic target in bone metastasis and provide a rationale for the development of MMP-9-specific inhibitors.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bone Neoplasms / enzymology*
  • Bone Neoplasms / secondary*
  • Bone and Bones / metabolism
  • Cell Line, Tumor
  • Cell Movement / physiology
  • Coculture Techniques
  • Enzyme Activation / physiology
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Immunohistochemistry
  • Male
  • Matrix Metalloproteinase 14
  • Matrix Metalloproteinase 2 / metabolism
  • Matrix Metalloproteinase 9 / metabolism
  • Matrix Metalloproteinases / metabolism*
  • Matrix Metalloproteinases, Membrane-Associated
  • Metalloendopeptidases / metabolism
  • Mice
  • Osteoclasts / metabolism*
  • Prostatic Neoplasms / enzymology*
  • Reverse Transcriptase Polymerase Chain Reaction


  • Mmp14 protein, mouse
  • Matrix Metalloproteinases
  • Matrix Metalloproteinases, Membrane-Associated
  • Metalloendopeptidases
  • Matrix Metalloproteinase 2
  • Matrix Metalloproteinase 9
  • Matrix Metalloproteinase 14