alpha v beta 3 and vitronectin expression by normal ovarian surface epithelial cells: Role in cell adhesion and cell proliferation

The alpha v beta 3 integrin and its ligand vitronectin are expressed by dif ferentiated epithelial ovarian carcinomas and carcinoma cell lines in cultu re. Moreover, alpha v beta 3/vitronectin interaction influences adhesion an d migration of ovarian carcinoma cells in culture. For a better understandi ng of the behavior of these carcinomas, it appeared necessary to study the characteristics of their normal counterpart, the ovarian surface epithelium (OSE). The present study showed that normal cultured human OSE cells, like the carcinoma cells, have the ability to synthesize vitronectin, The vitro nectin receptor, alpha v beta 3 integrin, is also expressed by OSE cells an d is localized in focal contacts close to paxillin, a focal contact-specifi c protein, and p125(FAK), a cytoskeletal and signaling molecule, This local ization suggested an active participation of the integrin in the adhesion a nd/or proliferation of OSE cells. Indeed, the use of a blocking antibody de monstrated that alpha v integrins promote OSE cell adhesion on vitronectin but not on fibronectin and that these integrins are required for maximal pr oliferative activity, The results suggest a role of the alpha v beta 3/vitr onectin system in normal OSE physiology and demonstrate that the expression of this system by well-differentiated ovarian carcinomas reflects the rete ntion of normal cell properties. (C) 1999 Academic Press.