1-O-OCTADECYL-2-O-METHYL-GLYCEROPHOSPHOSCHOLINE INHIBITS THE ADHESIONOF RAS-TRANSFORMED FIBROBLASTS TO HUMAN ENDOTHELIAL-CELLS

The adhesion of tumor cells to the endothelium is a key step in haemat ogenic metastasis. Because alkyllysophospholipids decrease tumor metas tasis, we investigated the effect of 1-O-octadecyl-2-O-methyl-glycerop hosphocholine (ET18-OCH3) on the adhesion of two highly metastatic ras -transformed 10T1/2 cell lines, CIRAS-2 and CIRAS-3, to confluent endo thelial cells. The order of adhesion to the endothelial cells was CIRA S-2 > 10T1/2 > CIRAS-3. RGD peptides were unable to inhibit the bindin g of the cells suggesting that adhesion was not mediated by fibronecti n or vitronectin. Treatment of the cell lines with 20 mu M ET18-OCH3 f or 24 h decreased the adhesion of CIRAS-2, CIRAS-3 and 10T1/2 to the e ndothelial cells by 50, 43 and 36% respectively. Thus interference in the adhesion of tumor cells to the endothelium could contribute to dec reased metastasis.