ML-390 is an inhibitor of dihydroorotate dehydrogenase (DHODH), the enzyme that converts dihydroorotate to orotate during de novo pyrimidine synthesis. In acute myeloid leukemia, leukemic myeloblast development is halted at an immature stage leading to perpetual self-renewal rather than differentiation. ML-390 induces differentiation in the acute myeloid leukemia cell lines U937 (murine) and THP-1 (human) cell lines with an EC50 value of approximately 2 μM.
