Cell surface overexpression of αvβ5 integrin impedes αvβ3-mediated migration of the human ovarian adenocarcinoma cell line IGROV1

Human ovarian surface epithelium and epithelial tumors express integrin αvβ5, which can interact with vitronectin. In addition, in vitro acquisition of cisplatin resistance by αvβ3-expressing IGROV1 cells is accompanied by cell-surface expression of integrin αvβ5. To further explore the role of αvβ5 in ovarian carcinoma cells, IGROV1 cells were stably transfected with a human β5 integrin cDNA construct, and three β5 transfectant clones were selected for the expression of αvβ5 integrin at their cell surface. Despite a delayed entry in the exponential phase of growth, β5-transfectant cells kept a proliferation ability similar to that of parental cells, while their growth rate was hindered in the presence of an anti-αvβ5 blocking antibody. Only simultaneous blockade of αvβ3 and αvβ5 by specific antibodies impeded the adhesion to vitronectin of β5 transfectants and of the β5-expressing cisplatin-resistant variant IGROV1-R10, suggesting that the two heterodimers cooperated in the regulation of this process. Cell surface expression of αvβ5 resulted in an attenuation of αvβ3-mediated migration on vitronectin. αvβ5 participated to migration events in the absence of exogenous growth factors only in one transfectant clone and in IGROV1-R10 cells. Finally, the response to cisplatin was not significantly modified in β5 transfectants when compared to IGROV1 parental cells.