Human ovarian adenocarcinoma cells synthesize vitronectin and use It to organize their adhesion

Extracellular matrix components and integrin receptors are frequently altered in cancer, including ovarian adenocarcinoma. Vitronectin (Vn) is a matrix protein mainly synthesized by liver cells; it is present in normal ovarian surface epithelium and differentiated ovarian adenocarcinoma, but is frequently undetectable in undifferentiated carcinoma (F. Carreiras et al., 1996, Gynecol Oncol 62:260-267). Wondering about the cellular origin of Vn in ovarian carcinoma, we searched for evidence of Vn synthesis by these tumors. We demonstrated that three human ovarian adenocarcinoma cell lines were able to synthesize Vn, as revealed by the presence of Vn mRNA and the protein. The Vn matrix promotes adhesion of ovarian tumor cells through alphav integrins. Moreover, during in vitro growth, Vn is progressively organized into a particular pattern in combination with the recruitment of alphav into focal contacts. Our results suggest that Vn synthesis may participate in ovarian adenocarcinoma cell biology and raise the possibility that altered expression of Vn in some ovarian carcinomas could result from a defect in Vn synthesis.