Human tumour-associated cell adhesion protein MN/CA IX: identification of M75 epitope and of the region mediating cell adhesion

MN/CA IX is a cell surface protein, strongly associated with several types of human carcinomas. It exerts activity of carbonic anhydrase and capacity of binding to cell surface receptors. in the present work, we used affinity purified MN/CA IX protein to demonstrate that the cells adhere to immobili zed MN/CA IX and that the monoclonal antibody M75 abrogates cell attachment to MN/CA IX, Using synthetic oligopeptides, we identified M75 epitope and located it in the proteoglycan domain, which contains a sixfold tandem repe at of six amino acids GEEDLP. From phage display library of random heptapep tides we identified and chemically synthesized those which compete for the epitope with M75 and inhibit adhesion of cells to MN/CA IX. These heptapept ides might serve as lead compounds for drug design. (C) 2000 Cancer Researc h Campaign.