Molecular targeting of inosine-5′-monophosphate dehydrogenase by FF-10501 promotes erythropoiesis via ROS/MAPK pathway

One of the major symptoms of myelodysplastic syndromes (MDS) is severe cytopenia. Despite cytokine therapies, such as erythropoiesis-stimulating agents, many patients still require blood transfusions, and the development of new therapeutic approaches is needed. In this work, we studied the effects of the inosine-5 '-monophosphate (IMP) dehydrogenase (IMPDH) inhibitor FF-10501 on erythropoiesis of human hematopoietic cells. Differentiation of K562 chronic myeloid leukemia cells to an erythroid lineage was promoted by FF-10501 in a dose-dependent manner. Interestingly, we found that metabolic conversion of IMP to hypoxanthine leads to elevation of reactive oxygen species (ROS). The differentiative effects of FF-10501 were abolished by the ROS scavenger dimethylthiourea or the p38 MAPK inhibitor SB203580. Furthermore, FF-10501 promoted erythropoiesis from CD34(+) hematopoietic stem/progenitor cells, accompanied with ROS accumulation, while high-dose FF-10501 mainly showed cytotoxic effects. These findings denote the potential of IMPDH inhibition therapy with FF-10501 in amelioration of anemia in MDS patients.