Cl-IB-MECA inhibits human erythropoiesis.

Candidate drugs are being sought for the suppression of human erythropoiesis. Cl-IB-MECA [2-chloro-N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide] is a derivative of adenosine that inhibits the growth of leukaemic cell lines. To determine the effects of Cl-IB-MECA upon erythropoiesis, studies were performed by using an ex vivo culture system of primary human CD34+ cells. Cl-IB-MECA suppressed erythroblast growth and maturation at doses >/=50 mumol/l through a mechanism of cell cycle inhibition and accumulation of cells in the G1/G0 phase. These findings demonstrate that Cl-IB-MECA inhibits human erythropoiesis, and suggest that further consideration of this drug is warranted for patients with erythrocytosis or polycythemia syndromes.