IDH1 Mutation Enhances Catabolic Flexibility and Mitochondrial Dependencies to Favor Drug Resistance in Acute Myeloid Leukemia

Isocitrate dehydrogenases (IDH) are involved in redox control and central metabolism. We hypothesized that key metabolic fluxes are selectively reprogrammed to maintain biosynthetic homeostasis and lower drug responses in IDH mutant acute myeloid leukemia cells. Here we show that metabolic reprogramming initiated by IDH1 mutation leads to marked increases in glucose, glutamine and fatty acid catabolism that along with enhancement of wild-type IDH enzyme activity contribute to provision of α-KG required for 2-HG synthesis and to replenish Krebs cycle intermediates for biosynthetic reactions, oxygen consumption and ATP production. Mechanistically, this occurs through both methylation-driven CEBPα activation of FAO and reprogramming of systemic metabolic fluxes through other pathways that augment catabolic flexibility. Consequently, this catabolic flexibility enhances Krebs cycle and OxPHOS activities that are not necessarily rescued by IDH mutant inhibitors or 2-HG reduction. This renders IDH1 mutant cells more resistant to chemotherapeutics but more susceptible to mitochondrial inhibition. Our findings provide a scientific rationale for innovative combinatory targeted therapies to treat this subgroup of patients, especially those unresponsive to or relapsing from IDH mutant-specific inhibitors.