Integrin expression in human melanoma cell lines: Heterogeneity of vitronectin receptor composition and function

Publisher Website
Google Scholar
Abstract
Ten human melanoma cell lines were examined for integrin-receptor expression using a panel of antibodies directed against different integrin subunits. Considerable heterogeneity was detected for levels of expression of 7 integrins, including the αvβ3 vitronectin receptor where a correlation between tumorigenic capacity in athymic nude mice and αvβ3 levels was found. Detailed analysis of the vitronectin receptor on these lines revealed heterogeneity of composition. In one cell line, VUP, an αvβ1 association was detected and, by antibody-inhibition studies, this receptor was shown to bind vitronectin as its ligand. In another line, DX3, evidence was obtained which indicated that apart from the qfi, receptor the αv was able to associate with another β subunit which was not β3. The existence of these alternative forms of the vitronectin receptor in this small sample of tumours of common origin might explain why the capacity to bind to fibrinogen and vitronectin substrates by these cells did not necessarily correlate with αvβ3 levels.