Alphav integrins mediate adhesion and migration of breast carcinoma cell lines

Integrins with the alphav subunit are involved in cell adhesion and cellular signaling. Some alphav integrins have been associated with tumor progression and dissemination. The objective of this study was to assess the contribution of alphav integrins to the adhesive and migratory behavior of cells derived from breast carcinoma (BCA). The expression and function of alphav integrins was characterized in three BCA cell lines which exhibit different metastatic potentials. These include MCF-7 cells which metastasize inefficiently, MDA-MB-231 cells, which have a moderate metastatic potential, and MDA-MB-435 cells, which metastasize extensively. Each cell type displays a different repertoire of alphav integrins on the cell surface. The complement of alphav integrins on each cell type influences their ability to adhere and migrate. The most striking difference among these cell lines was the expression of the alphavbeta3 integrin. The highly metastatic MDA-MB-435 cells express substantial levels of this receptor, whereas MDA-MB-231 and MCF-7 cells do not. The MDA-MB-435 cells showed a greater ability to adhere and to migrate and this functional difference can largely be attributed to the expression of alphavbeta3 integrin. This characterization is a first step toward determining the role of alphav integrins in animal models of BCA metastasis, and lends support to the hypothesis that the alphavbeta3 integrin can be a contributing factor in metastatic disease.