AFFINITY OF INTEGRINS FOR DAMAGED EXTRACELLULAR-MATRIX - ALPHA-V-BETA-3 BINDS TO DENATURED COLLAGEN TYPE-I THROUGH RGD SITES

Cellular adhesion receptors termed integrins play an important role in the interaction of cells with extracellular matrix (ECM) during wound healing, development and tumorigenesis. During such events, ECM may become modified or damaged which could alter the types of adhesive signals presented to cells. In this study, cell adhesion and affinity chromatography experiments were performed to determine whether different integrins interact with denatured versus native ECM molecules. Human melanoma cells were found to adhere to denatured versus native type I collagen through different integrins. The cells adhere to denatured collagen through the αvβ3 integrin and this interaction is inhibited by an RGD containing peptide but not by a control peptide. In contrast, adhesion to native type I collagen appears to be mediated by several β1 integrins and thus, is not inhibited by either αvβ3 antibodies or the RGD peptide. Affinity chromatography reveals a marked increase in the quantity of αvβ3 isolated on denatured collagen versus native collagen-sepharose. These results suggest that RGD sites in type I collagen may be masked and that they become exposed upon denaturation of the molecule. Wounding of extracellular matrix may, thus, expose RGD sites in collagens that facilitate the interaction of cells with damaged extracellular matrix through RGD binding integrins. © 1992.