Rapid activation of matrix metalloproteinase-2 by glioma cells occurs through a posttranslational MT1-MMP-dependent mechanism.

Abstract

Matrix metalloproteinase-2 (MMP-2) has been suggested to play a crucial role in tumor invasion and angiogenesis. In order to understand the mechanisms underlying proMMP-2 activation, we compared the biochemical and cellular events triggered by two potent MMP-2 activators, the lectin concanavalin A (ConA) and the cytoskeleton disrupting agent cytochalasin D (CytoD). Incubation of U87 human glioma cells for 24 h in the presence of ConA or CytoD induced a marked activation of proMMP-2 and this activation was correlated in both cases with an increase in the mRNA levels of MT1-MMP. At the protein level, proMMP-2 activation induced by CytoD or ConA strongly correlated with the appearance of a 43-kDa MT1-MMP proteolytic breakdown product in cell lysates. Interestingly, CytoD also induced a very rapid (2 h) activation of proMMP-2 that was independent of protein synthesis. Under these conditions, CytoD also promoted the rapid proteolytic breakdown of the 63 kDa pro form of MT1-MMP, resulting in the appearance of the 43 kDa MT1-MMP processed form. Overexpression of a recombinant full-length MT1-MMP protein in glioma cells resulted in the activation of proMMP-2 that was correlated with the generation of the 43 kDa fragment of the protein. By contrast, overexpression of the protein in COS-7 cells promoted proMMP-2 activation without inducing the production of the 43 kDa fragment. These results thus suggest that activation of proMMP-2 occurs through both translational and post-translational mechanisms, both involving proteolytic processing of membrane-associated MT1-MMP. This processing of MT1-MMP is, however, not essential to proMMP-2 activation but may represent a regulatory mechanism to control the activity of MT1-MMP.

• Authors: D Gingras, M Pagé, B Annabi, R Béliveau
• Journal: Biochimica et biophysica acta (Biochim Biophys Acta) Vol. 1497 Issue 3 Pg. 341-50 (Sep 20 2000) ISSN: 0006-3002 [Print] Netherlands
• PMID: 10996658 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Culture Media, Conditioned
• Enzyme Inhibitors
• Extracellular Matrix Proteins
• Protein Precursors
• RNA, Messenger
• Concanavalin A
• Cytochalasin D
• Matrix Metalloproteinases, Membrane-Associated
• Metalloendopeptidases
• Matrix Metalloproteinase 2

Topics

• Concanavalin A (pharmacology)
• Culture Media, Conditioned
• Cytochalasin D (pharmacology)
• Enzyme Activation
• Enzyme Inhibitors (pharmacology)
• Extracellular Matrix Proteins (metabolism)
• Gene Expression Regulation, Enzymologic
• Glioma
• Humans
• Immunoblotting
• Matrix Metalloproteinase 2 (metabolism)
• Matrix Metalloproteinases, Membrane-Associated
• Metalloendopeptidases (genetics, metabolism)
• Protein Precursors (metabolism)
• RNA, Messenger (analysis)
• Reverse Transcriptase Polymerase Chain Reaction
• Signal Transduction (drug effects)
• Tumor Cells, Cultured