CD44 PLAYS A ROLE IN ADHESIVE INTERACTIONS BETWEEN GLIOMA-CELLS AND EXTRACELLULAR-MATRIX COMPONENTS

Glioma invasion is a complex process involving interactions of tumour cells with host cells and extracellular matrix (ECM). The initial even t in the process is recognition and attachment of glioma cells to spec ific ECM molecules prior to migration into proteolytically modified ma trix. In comparison with other tissues, brain ECM is a relatively amor phous matrix which contains glycosaminoglycans including hyaluronan (H A). Recently CD44 which is a transmembrane adhesion molecule found on a wide variety of cells, has been suggested as the principal cell surf ace receptor for HA, In the present in vitro investigation we have ana lysed the role of CD44 in adhesive interactions between human gliomas and ECM. Our experimental procedures included immunocytochemistry, imm unoblotting, in vitro adhesion assay and now cytometry. CD44 was expre ssed on the surface of all gliomas analysed (9) and the level of expre ssion showed no correlation with tumour grade. Eighty, 95 and 120 kDa isoforms were demonstrated by immunoblotting. In an adhesion blocking assay it was found that ligation of CD44 with specific antibody result ed in reduced adhesion to hyaluronan, chondroitin sulphate, fibronecti n, laminin, collagen IV and Matrigel(TM). We conclude that CD44 is inv olved in adhesion of glioma cells to a wide range of ECM components.