Effect of alpha3beta1 and alphavbeta3 integrin glycosylation on interaction of melanoma cells with vitronectin.

Abstract

The metastatic transformation of melanocytes is associated with altered expression of adhesion molecules, including alpha(v)beta(3) and alpha(3)beta(1) integrins. Integrin alpha(v)beta(3) is a primary vitronectin (VN) receptor, while both integrin types take part in adhesion to VN when they are in complex with uPAR. Although their role in melanoma cell interaction with VN is of great interest, the influence of N-oligosaccharides attached to these glycoproteins is still unappreciated. The present study assesses the role of alpha(v)beta(3) and alpha(3)beta(1) integrins and the influence of their glycosylation status on WM9 and WM239 metastatic melanoma cell interactions with VN. Cell adhesion to and migration on VN were selected as the studied cell behaviour parameters. Function-blocking antibodies and swainsonine (SW) treatment were used in these tests. Both cell lines interacted with VN in an integrin-mediated but cell-line-specific manner. In WM9 cells, migration was not completely inhibited by antibodies against alpha(3)beta(1) or alpha(v)beta(3) integrins, suggesting the participation of other VN receptors. In both cell lines in coprecipitation test the formation of an integrins/uPAR complex was shown. In the presence of SW formation of the complex did not occur, suggesting the participation of glycosylation in this process. Additionally, the adhesion properties of WM9 cells were changed after SW treatment. Our results suggest that in these two metastatic cell lines integrin-linked N-oligosaccharides influence the VN adhesion receptor activity and function.