The malaria parasite activates anion channels in the host erythrocyte which prevent colloidosomotic hemolysis of the host cell. Channel activation involves parasite-derived oxidative stress and autocrine purinergic signalling. To allow the application of RNA interference technology, experiments were performed to explore, whether K562 leucemic cells - as a nucleated erythrocyte model system - express similar anion channels. The cells were oxidized (1 mM (tBHP/30 min) and the osmolyte channel activity was analyzed by colloidosmotic lysis in isosmotic sorbitol solution, patch-clamp whole-cell recording, and MQAE fluorescence. Oxidation stimulated NPPB (50 mM)-sensitive sorbitol lysis and whole-cell anion current. The latter exhibited a permselectivity of Cl-> lactate >> gluconate. MQAE fluorescence similarly demonstrated an oxidation-stimulated anion permeability with a permselectivity of NO3-[cong] Br- > lactate >> gluconate and a blocker sensitivity of NPPB > DIDS > furosemide >> glybenclamide. ATP (100 mM) enhanced and the nonspecific purinoceptor antagonist suramin (10 mM) blunted the oxidation-induced activation of the anion and sorbitol permeability. In conclusion, K562 leukemic cells express oxidant sensitive anion and organic osmolyte channels similar to those in erythrocytes. Thus, K562 leukemic cells may serve as a nucleated model system for the molecular identification of those channels.