The IDH2 mutation cooperates with the NPM1 mutation to activate Hoxa9/Meis1 and hypoxia pathways in acute myeloid leukemia (expression)

Mutations in IDH1 and IDH2 are frequently observed in various cancers, including acute myeloid leukemia (AML). Mutant IDHs convert -ketoglutarate (-KG) to 2-hydroxyglutarate (2-HG), which dysregulates a set of-KG-dependent dioxygenases. To determine whether mutant IDHs are valid targets for cancer therapy, we established a mouse AML model harboring an IDH2 mutation by transplanting mice with nucleophosmin1 (NPM1)+/- mouse hematopoietic stem/progenitor cells that had been co-transduced with four mutant genes (NPMc, IDH2/R140Q, DNMT3A/R882H and FLT3/ITD) that frequently occur simultaneously in human AML patients. IDH2/R140Q is necessary for the engraftment or survival of NPMc+ cells in vivo.Gene-expression analysis indicated that NPMc increased the expression of Hoxa9, and that IDH2/R140Q increased the level of Meis1 and activated the hypoxia pathway in AML cells.Conditional deletion of IDH2/R140Q blocked 2-HG production and maintenance of leukemia stem cells, resulting in survival of the AML mice. IDH2/R140Q reversibly decreased the levels of 5hmC modification and gene expression at some differentiation inducing genes (Ebf1, Pax5 and Spib). These results indicate that the IDH2 mutation is critical for the development and maintenance of AML stem cells, and that mutant IDHs are promising targets for anticancer therapy.

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Ogawara Y, Katsumoto T, Aikawa Y, Shima Y, Kagiyama Y, Soga T, Matsunaga H, Seki T, Araki K, Kitabayashi I