Collagen-Induced Invasion in Breast Cancer
Abstract
Overexpression of activated c-Src leads to increased invasive behavior in MDA-MB-23 1 cells. Localized matrix degradation at invadopodia was increased more than 4 fold. Zymogram analysis of conditioned media from these cells demonstrated that the level of the extracellular matrix degrading metalloproteinase, MMP-9 was dramatically up regulated in transfected cells expressing constitutively activated c-Src (Y527F). Conversely, expression levels of MMP-9 in transfected cells expressing the dominant negative, kinase inactive c-Src (K295R) were suppressed. Matrix degradation could be inhibited using a monoclonal antibody that blocked the enzyme activity of MMP-9. These results suggest that membrane-associated MMP-9 was largely responsible for the localized matrix degradation observed at invadopodia in cells over-expressing kinase activated c-Src. Subcellular fractionation confirmed the localization of MMP-9 to invadopodia-enriched fractions. Interestingly, activated MMP- 2 was also present in these fractions. Co-immunoprecipitation, Western blotting and zymography demonstrated that MMP-9 is localized at invadopodia via an interaction with the cell surface receptor, alpha3 integrin. Levels of integrin expression were not modulated by c-Src transfections. We conclude that c-Src activation promotes invasion, in part by increasing the expression of MMP-9, which associates with alpha3 integrin to promote localized matrix degradation at invadopodia.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1999
- Accession Number
- ADB257715
Entities
People
- Emma Bowden
Organizations
- Georgetown University