Acute myeloid leukemia (AML) with an 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. In addition, gilteritinib treatment was associated with decreased ATP production and glutathione synthesis and increased reactive oxygen species, resulting in cellular senescence. Finally, we found that the glutaminase inhibitor CB-839 enhanced antileukemic 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.

中文翻译：

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Gilteritinib 抑制 FLT3-ITD 阳性 AML 中的谷氨酰胺摄取和利用

具有 FLT3 内部串联重复 (FLT3 -ITD) 突变的急性髓性白血病 (AML) 是一种侵袭性血液系统恶性肿瘤，与频繁复发和总生存期差有关。酪氨酸激酶抑制剂 gilteritinib 被批准用于治疗具有 FLT3 突变的复发/难治性 AML，但其作用机制尚不完全清楚。在这里，我们试图确定可用于增强 gilteritinib 抗白血病作用的其他治疗靶点。基于无偏转录组学分析，我们将谷氨酰胺转运蛋白 SNAT1 (SLC38A1) 确定为 gilteritinib 的新靶点，导致白血病细胞内谷氨酰胺摄取和利用受损。使用代谢组学和代谢通量分析，我们发现 gilteritinib 通过 TCA 循环和癌代谢物 2-羟基戊二酸的细胞水平降低了谷氨酰胺代谢。此外，gilteritinib 治疗与 ATP 产生和谷胱甘肽合成减少以及活性氧种类增加有关，从而导致细胞衰老。最后，我们发现谷氨酰胺酶抑制剂 CB-839 在体外研究中增强了 gilteritinib 的抗白血病作用，该研究使用人类原发性 FLT3 -ITD 阳性 AML 细胞，其中异柠檬酸脱氢酶突变，该酶催化异柠檬酸的氧化脱羧，产生 α-酮戊二酸. 总的来说，这项工作已经确定了 SLC38A1 下游的一个以前未被识别的、对 gilteritinib 敏感的代谢途径，它导致谷氨酰胺分解减少和氧化还原稳态的破坏。