Implication of the αvβ3 integrin in the adhesion of the ovarian‐adenocarcinoma cell line IGROV1

Abstract

Accumulating evidence suggests that integrins, which participate in many complex cellular processes, are important for tumor progression and metastasis. In order to understand the role of these cell-surface receptors and of their ligands in the biological behavior of ovarian tumor cells, we have examined the expression of integrins in the human ovarian-adenocarcinoma cell line IGROVI. These cells expressed the αv sub-unit and used it to attach on vitronectin (Vn). A monoclonal antibody (MAb) (69-6-5) specific to αv blocked the attachment of IGROVI cells on Vn and fibrinogen (Fg), but not on fibronectin (FN) and other adhesive ligands. Immunoprecipitation of surface biotinylated cells followed by Western blotting showed that the αv sub-unit was associated with β3, but not with β1, β5 or β6. When cells were cultivated on glass coverslips or on Vn sub-stratum in serum-free medium, immunofluorescence staining with MAb 69-6-5 revealed the presence of αv at cell-cell contacts and at focal contacts, supporting its active participation in adhesion as part of a functional heterodimer. Furthermore, immunofluorescence data showed the presence of Vn as a fibrillar network in IGROVI cells cultivated on FN-coated slides. These results suggest that αvβ3 and its Vn ligand may play a important role in the behavior of ovarian epithelial tumors.