Gilteritinib Inhibits Glutamine Uptake and Utilization in FLT3-ITD–Positive AML

Abstract

Acute myeloid leukemia (AML) with a FLT3 internal tandem duplication (FLT3-ITD) mutation is an aggressive hematologic malignancy associated with frequent relapse and poor overall survival.The tyrosine kinase inhibitor gilteritinib is approved for the treatment of relapse/refractory AML with FLT3 mutations, yet its mechanism of action is not completely understood. Here, we sought to identify additional therapeutic targets that can be exploited to enhance gilteritinib's antileukemic effect. Based on unbiased transcriptomic analyses, we identified the glutamine transporter SNAT1 (SLC38A1) as a novel target of gilteritinib that leads to impaired glutamine uptake and utilization within leukemic cells. Using metabolomics and metabolic flux analyses, we found that gilteritinib decreased glutamine metabolism through the TCA cycle and cellular levels of the oncometabolite 2-hydroxyglutarate. Additionally, gilteritinib treatment was associated with decreased ATP production and glutathione synthesis and increased reactive oxygen species, resulting in cellular senescence. Lastly, we found that the glutaminase inhibitor CB-839 enhanced anti-leukemic effect of gilteritinib in ex vivo studies using human primary FLT3-ITD-positive AML cells harboring mutations in the enzyme isocitrate dehydrogenase, which catalyzes the oxidative decarboxylation of isocitrate, producing α-ketoglutarate. Collectively, this work has identified a previously unrecognized, gilteritinib-sensitive metabolic pathway downstream of SLC38A1 that causes decreased glutaminolysis and disruption of redox homeostasis. These findings provide a rationale for the development and therapeutic exploration of targeted combinatorial treatment strategies for this subset of relapse/refractory AML.

Inhibition of Mcl-1 Synergistically Enhances the Antileukemic Activity of Gilteritinib and MRX-2843 in Preclinical Models of FLT3-Mutated Acute Myeloid Leukemia

“…In this study, we have similarly found that FLT3 inhibition enhances AZD5991-induced cytochrome c release. Given that gilteritinib treatment has been reported to decrease the oxygen consumption rate in FLT3 -ITD AML cells, indicating a reduction in oxidative phosphorylation [ 44 ], this may also play a role in the mechanism of action, though further investigation into this mechanism of action is beyond the scope of this manuscript.…”

Deciphering the Role of Pyrvinium Pamoate in the Generation of Integrated Stress Response and Modulation of Mitochondrial Function in Myeloid Leukemia Cells through Transcriptome Analysis

“…For example, glutaminolysis was identified as synthetically lethal with FLT3-TKI treatment, indicating the potency of using amino acid depletion in combination therapies [ 56 , 57 ]. Another FLT3-TKI gilteritinib was also proved to hinder glutamine uptake and utilization in FLT3 -ITD–positive AML [ 58 ]. Recently, NEI-01, a novel arginine-depleting enzyme, could not only induce arginine deprivation, but also had cytotoxic activity against arginine auxotrophic AML cells through induction of cell cycle arrest and apoptosis [ 59 ].…”

Amino acids in hematologic malignancies: Current status and future perspective

“…In FLT3-internal tandem duplication (FLT3-ITD)-positive AML, a subtype of leukemia with notoriously dismal outcome, CB-839 also impaired GSH production, induced severe mitochondrial oxidative stress and cell apoptosis. More remarkably, CB-839 and FLT3 inhibitors, including AC220 and gilteritinib, exerted synergistic pro-apoptotic effects and displayed more potent anti-leukemia effect (42,43). These redox-targeted combinations represented a novel therapeutic strategy with high efficiency, low toxicity and enormous potential for clinical translation (44).…”