Glutaminolysis is a metabolic dependency in FLT3ITD acute myeloid leukemia unmasked by FLT3 tyrosine kinase inhibition.

FLT3 internal tandem duplication (FLT3ITD) mutations are common in acute myeloid leukemia (AML) associated with poor patient prognosis. Although new-generation FLT3 tyrosine kinase inhibitors (TKI) have shown promising results, the outcome of FLT3ITD AML patients remains poor and demands the identification of novel, specific, and validated therapeutic targets for this highly aggressive AML subtype. Utilizing an unbiased genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 screen, we identify GLS, the first enzyme in glutamine metabolism, as synthetically lethal with FLT3-TKI treatment. Using complementary metabolomic and gene-expression analysis, we demonstrate that glutamine metabolism, through its ability to support both mitochondrial function and cellular redox metabolism, becomes a metabolic dependency of FLT3ITD AML, specifically unmasked by FLT3-TKI treatment. We extend these findings to AML subtypes driven by other tyrosine kinase (TK) activating mutations and validate the role of GLS as a clinically actionable therapeutic target in both primary AML and in vivo models. Our work highlights the role of metabolic adaptations as a resistance mechanism to several TKI and suggests glutaminolysis as a therapeutically targetable vulnerability when combined with specific TKI in FLT3ITD and other TK activating mutation-driven leukemias.P.G. is funded by the Wellcome Trust (109967/Z/15/Z) and was previously supported by the Academy of medical Sciences and Lady Tata Memorial Trust. The Huntly lab is funded by European Research Council, MRC, Bloodwise, the Kay Kendall Leukaemia Fund, the Cambridge NIHR Biomedical Research Centre, and core support grants to the Wellcome Trust - Medical Research Council Cambridge Stem Cell Institute. C.F. and A.S.H.C are funded by the Medical Research Council, Core Grant to the Cancer Unit. P.M-P. is supported by a grant from Cancer Research UK (C56179/A21617). D.S. is a Postdoctoral Fellow of the Mildred-Scheel Organisation, German Cancer Aid. This research was supported by the CIMR Flow Cytometry Core Facility. We would like to thank the Welcome Trust Sanger Institute facility for the MiSeq run