Osteoblast-derived TGF-beta1 modulates matrix degrading protease expression and activity in prostate cancer cells

Int J Cancer. 2000 Feb 1;85(3):407-15.


Tumor progression and metastasis may result in part from the selection of cell clones competent for survival, invasion and growth at secondary sites and characterized by loss of growth inhibitory responses, acquisition of increased adhesiveness and enhanced motility and protease expression. Transforming growth factor-beta1 (TGF-beta1) is produced by osteoblasts (OB) in a latent form and is activated by proteases in a cell-dependent manner. We show here that OB conditioned medium (OB CM) modulates Matrigel invasion of a bone metastatic prostate cancer cell line (PC3) and that this effect is blocked by antibody against TGF-beta1 and by uPA/plasmin inhibitors, suggesting that TGF-beta1 can modulate OB-mediated cell recruitment and that PC3 cells can activate TGF-beta1. TGF-beta1 induces uPA and PAI-1 secretion and promotes binding of uPA at the external plasma membrane with increased membrane-associated plasmin activity. Matrix metalloprotease-9 (MMP-9) is induced both in the medium and in the membrane associated form. Moreover, the balance between proteolytic activity and inhibition is crucial in the metastatic event. Indeed, the increment of PAI-1 could have an important regulatory role on the extracellular proteolysis and might explain the decrease of net PA and gelatinolytic activities measured in the medium. In addition, PAI-1 plays a regulative role localizing matrix degradation in some specific sites, such as areas of cell-to-cell or cell-to-ECM contacts. In conclusion, TGF-beta1 enhances PC3 Matrigel invasion by a uPA/plasmin-dependent mechanism, also involving the MMP-9, and thus may play a central role in malignant prostate tumor progression as a result of stimulating bone matrix invasion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology
  • Biocompatible Materials / pharmacology
  • Blotting, Western
  • Bone Neoplasms / metabolism*
  • Bone Neoplasms / secondary
  • Collagen / pharmacology
  • Culture Media, Conditioned
  • Disease Progression
  • Drug Combinations
  • Endopeptidases / biosynthesis*
  • Endopeptidases / drug effects
  • Extracellular Matrix / drug effects
  • Extracellular Matrix / metabolism*
  • Fluorescent Antibody Technique
  • Gene Expression Regulation, Enzymologic / drug effects
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Laminin / pharmacology
  • Male
  • Matrix Metalloproteinase 9 / metabolism
  • Membrane Proteins / metabolism
  • Neoplasm Invasiveness
  • Osteoblasts / drug effects
  • Osteoblasts / metabolism*
  • Plasminogen Activator Inhibitor 1 / metabolism
  • Precipitin Tests
  • Prostatic Neoplasms / enzymology*
  • Prostatic Neoplasms / pathology
  • Protease Inhibitors / pharmacology
  • Proteoglycans / pharmacology
  • Rabbits
  • Tissue Inhibitor of Metalloproteinases / pharmacology
  • Transforming Growth Factor beta / metabolism*
  • Tumor Cells, Cultured
  • Urokinase-Type Plasminogen Activator / metabolism


  • Antineoplastic Agents
  • Biocompatible Materials
  • Culture Media, Conditioned
  • Drug Combinations
  • Laminin
  • Membrane Proteins
  • Plasminogen Activator Inhibitor 1
  • Protease Inhibitors
  • Proteoglycans
  • Tissue Inhibitor of Metalloproteinases
  • Transforming Growth Factor beta
  • matrigel
  • Collagen
  • Endopeptidases
  • Urokinase-Type Plasminogen Activator
  • Matrix Metalloproteinase 9