Identification of a selective inhibitor of IDH2/R140Q enzyme that induces cellular differentiation in leukemia cells
Jiao Chen, Jie Yang, Qingyun Wei, Ling Weng, Fei Wu, Yun Shi, Xiaolan Cheng, Xueting Cai, Chunping Hu, Peng Cao
Abstract
BACKGROUND: IDH2/R140Q mutation is frequently detected in acute myeloid leukemia (AML). It contributes to leukemia via accumulation of oncometabolite D-2-HG. Therefore, mutant IDH2 is a promising target for AML. Discovery of IDH2 mutant inhibitors is in urgent need for AML therapy. METHODS: Structure-based in silico screening and enzymatic assays were used to identify IDH2/R140Q inhibitors. Molecular docking, mutant structure building and molecular dynamics simulations were applied to investigate the inhibitory mechanism and selectivity of CP-17 on IDH2/R140Q. TF-1 cells overexpressed IDH2/R140Q mutant were used to study the effects of CP-17 on cellular proliferation and differentiation, the wild-type TF-1 cells were used as control. The intracellular D-2-HG production was measured by LC-MS. The histone methylation was evaluated with specific antibodies by western blot. RESULTS: of 40.75 nM against IDH2/R140Q. More importantly, it shows poor activity against the wild-type IDH1/2, resulting in a high selectivity of over 55 folds, a dramatic improvement over previously developed inhibitors such as AGI-6780 and Enasidenib. Molecular simulations suggested that CP-17 binds to IDH2/R140Q at the allosteric site within the dimer interface through extensive polar and hydrophobic interactions, locking the enzyme active sites in open conformations with abolished activity to produce D-2-HG. Cellular assay results demonstrated that CP-17 inhibits intracellular D-2-HG production and suppresses the proliferation of TF-1 erythroleukemia cells carrying IDH2/R140Q mutant. Further, CP-17 also restores the EPO-induced differentiation that is blocked by the mutation and decreases hypermethylation of histone in the TF-1(IDH2/R140Q) cells. CONCLUSIONS: These results indicate that CP-17 can serve as a lead compound for the development of inhibitory drugs against AML with IDH2/R140Q mutant. Video abstract.