Novel IDH1 Mutant Inhibitors for Treatment of Acute Myeloid Leukemia (expression)

Neomorphic mutations in isocitrate dehydrogenase 1 (IDH1) are driver mutations in acute myeloid leukemia (AML) and other cancers. We report the development of new allosteric inhibitors of mutant IDH1. Crystallographic and biochemical results demonstrated that compounds of this chemical series bind to an allosteric site and lock the enzyme in a catalytically inactive conformation, thereby enabling inhibition of different clinically relevant IDH1 mutants. Treatment of IDH1 mutant primary AML cells uniformly led to a decrease in intracellular 2-HG, abrogation of the myeloid differentiation block and induction of granulocytic differentiation at the level of leukemic blasts and more immature stem-like cells, in vitro and in vivo. Molecularly, treatment with the inhibitors led to a reversal of the DNA cytosine hypermethylation patterns caused by mutant IDH1 in AML patients cells. Our study provides proof-of-concept for the molecular and biological activity of novel allosteric inhibitors for targeting different mutant forms of IDH1 in leukemia. To obtain insight into the molecular mechanism for the induction of granulocytic differentiation and cell death following inhibition of IDH1 mutant protein in primary AML cells, we performed gene expression microarrays following treatment with either GSK321 IDH1 inhibitor or Controls (DMSO or GSK990 inactive inhibitor).

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Okoye-Okafor UC, Bartholdy B, Cartier J, Gao EN, Pietrak B, Rendina AR, Rominger C, Quinn C, Smallwood A, Wiggall KJ, Reif AJ, Schmidt SJ, Qi H, Zhao H, Joberty G, Faelth-Savitski M, Bantscheff M, Drewes G, Duraiswami C, Brady P, Groy A, Narayanagari SR, Antony-Debre I, Mitchell K, Wang HR, Kao YR, Christopeit M, Carvajal L, Barreyro L, Paietta E, Makishima H, Will B, Concha N, Adams ND, Schwartz B, McCabe MT, Maciejewski J, Verma A, Steidl U