Matrix Metalloproteinase 2-Integrin αvβ3 Binding Is Required for Mesenchymal Cell Invasive Activity but Not Epithelial Locomotion: A Computational Time-Lapse Study

Cellular invasive behavior through three-dimensional collagen gels was analyzed using computational time-lapse imaging. A subpopulation of endocardial cells, derived from explanted quail cardiac cushions, undergoes an epithelial-to-mesenchymal transition and invades the substance of the collagen gels when placed in culture. In contrast, other endocardial cells remain epithelial and move over the gel surface. Here, we show that integrin alpha v beta 3 and matrix metalloproteinase (MMP)2 are present and active in cushion mesenchymal tissue. More importantly, functional assays show that mesenchymal invasive behavior is dependent on MMP2 activity and integrin alpha v beta 3 binding. Inhibitors of MMP enzymatic activity and molecules that prevent integrin alpha v beta 3 binding to MMP2, via its hemopexin domain, result in significantly reduced cellular protrusive activity and invasive behavior. Computational analyses show diminished intensity and persistence time of motility in treated invasive mesenchymal cells, but no reduction in motility of the epithelial-like cells moving over the gel surface. Thus, quantitative time-lapse data show that mesenchymal cell invasive behavior, but not epithelial cell locomotion over the gel surface, is partially regulated by the MMP2-integrin interactions.