HUMAN OVARIAN TUMOR-CELLS CAN BIND HYALURONIC-ACID VIA MEMBRANE CD44 - A POSSIBLE STEP IN PERITONEAL METASTASIS

Our previous studies have suggested that the interaction between hyalu ronic acid (HA) on peritoneal mesothelial cells and the membrane adhes ion molecule, CD44, on ovarian tumour cells could be important in ovar ian cancer metastasis. In order to study this further, adhesion of six ovarian tumour lines to HA coated on to a plastic surface was investi gated, Four Lines bound to the HA coat and two lines did not, The adhe sive lines were those that expressed high amounts of CD44, but the deg ree of adhesion was not closely correlated,vith CD44 expression, The r esults suggested that different tumour Lines had different affinities for HA, Treatment of the HA coat with hyaluronidase substantially redu ced adhesion, Adhesion was also partially reduced if the tumour cells were preincubated with either soluble HA, or anti-CD44 antibodies dire cted against the HA binding region, An antibody against a non-HA bindi ng region only slightly blocked adhesion at high antibody concentratio ns. Only the CD44H isoform was detected by immunoprecipitation on the tumour cells, These results suggest that ovarian tumour cells can atta ch to immobilised HA via CD44H on the cell membrane.