CD44-mediated metabolic rewiring is a targetable dependency of IDH-mutant leukemia

Abstract

Recurrent isocitrate dehydrogenase (IDH) mutations catalyze nicotinamide adenine dinucleotide phosphate (NADPH)-dependent production of oncometabolite (R)-2-hydroxyglutarate (R-2HG) for tumorigenesis. IDH inhibition provides clinical response in a subset of acute myeloid leukemia (AML) cases; however, most patients develop resistance, highlighting the need for more effective IDH-targeting therapies. By comparing transcriptomic alterations in isogenic leukemia cells harboring CRISPR base-edited IDH mutations, we identify the activation of adhesion molecules including CD44, a transmembrane glycoprotein, as a shared feature of IDH-mutant leukemia, consistent with elevated CD44 expression in IDH-mutant AML patients. CD44 is indispensable for IDH-mutant leukemia cells through activating pentose phosphate pathway and inhibiting glycolysis by phosphorylating glucose-6-phosphate dehydrogenase and pyruvate kinase muscle isozyme M2, respectively. This metabolic rewiring ensures efficient NADPH generation for mutant IDH-catalyzed R-2HG production. Combining IDH inhibition with CD44 blockade enhances the elimination of IDH-mutant leukemia cells. Hence, we describe an oncogenic feedforward pathway involving CD44-mediated metabolic rewiring for oncometabolite production, representing a potentially targetable dependency of IDH-mutant malignancies.