Effects of suramin on PMN interactions with different surfaces

Human polymorphonuclear leukocytes (PMN) were found to lightly adhere on en dothelial (lines EAhy926 and ECV304) and collagen surfaces under the influe nce of the chemotherapeutic drug suramin. This was observed by scanning ele ctron microscopy and quantitated by myeloperoxidase assays. Suramin also in hibited Ca2+ ionophore A23187-stimulated leukotriene (LT) synthesis in PMN interaction with endothelial cells or with collagen surface. Suramin decrea sed the release of radiolabeled arachidonic acid (AA) and 5-lipoxygenase (5 -LO) metabolites by prelabeled PMN stimulated with A23187. Using agents rel easing the suramin-stimulated adhesion namely jasplakonolide and dextran su lfate, we observed a reversal of the suramin effect on leukotriene synthesi s. Jasplakonolide released the adhesion of PMN on endothelial and collagen- coated surfaces and restored 5-LO activity. Dextran-sulfate released adhesi on on collagen-coated surfaces and abolished suramin inhibition. Arachidona te could also overcome adhesion and inhibition of 5-LO. We conclude that su ramin-induced tight attachment of PMN on to solid surfaces lead to decrease d leukotriene synthesis during subsequent A23187 stimulation in the absence of exogenous substrates.