Collagen-induced rapid morphogenesis of human mammary epithelial cells: The role of the «2/*i integrin

The cell line MTSV1-7, originally derived by immortalizing mammary epithelial cells cultured from human milk was able to form three-dimensional structures in collagen gel. We have now found that these cells, cultured as a monolayer, are able to undergo rapid morphogenesis forming ridges and balls around collagen fibres, when soluble collagen type I is added to the medium. Monoclonal antibodies to the a2(PlE6) and fi\(mAB13) subunits of VLA-2, but not to the a3-subunit (P1B5) of VLA-3, could block this collagen-induced rapid morphogenesis (CIRM). The effect of the antibodies on cell attachment, spreading, and migration on collagen gels was analyzed to identify «2j3i dependent steps which might be involved in CIRM. The results suggest that while other proteins, besides a2fil, are also involved in cell attachment and migration, cell spreading was specifically blocked by antibodies to the VLA-2, but not to the VLA-3 integrin. The results demonstrate that the (iifl\ integrin plays a crucial role in the collageninduced morphogenesis of human mammary epithelial cells and implicate the process of VLA-2-dependent cell spreading as an important step in this morphogenesis.