UPTAKE OF SURAMIN BY HUMAN MICROVASCULAR ENDOTHELIAL-CELLS

We have demonstrated for the first time that suramin is taken up by hu man dermal microvascular endothelial (HMEC-1) cells by an active proce ss involving the caveolae system. The uptake of suramin was time-depen dent and reduced by more than 90% when incubated in the presence of al bumin or at 4 degrees C. Suramin uptake was also inhibited when incuba ted in the presence of filipin and digitonin, both potent cholesterol- binding agents, but not in the presence of probenecid. The [H-3]surami n taken up by the HMEC-1 cells was located primarily within the nucleu s, followed by the cytoplasmic fraction. The presence of suramin in th ese cellular compartments suggests that this drug may act through intr acellular mechanisms. Published by Elsevier Science Ireland Ltd.