BackgroundPancreatic ductal adenocarcinomas (PDA) activate a glutamine-dependent pathway of cytosolic nicotinamide adenine dinucleotide phosphate (NADPH) production to maintain redox homeostasis and support proliferation. Enzymes involved in this pathway (GLS1 (mitochondrial glutaminase 1), GOT1 (cytoplasmic glutamate oxaloacetate transaminase 1), and GOT2 (mitochondrial glutamate oxaloacetate transaminase 2)) are highly upregulated in PDA, and among these, inhibitors of GLS1 were recently deployed in clinical trials to target anabolic glutamine metabolism. However, single-agent inhibition of this pathway is cytostatic and unlikely to provide durable benefit in controlling advanced disease.ResultsHere, we report that reducing NADPH pools by genetically or pharmacologically (bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl)ethyl sulfide (BPTES) or CB-839) inhibiting glutamine metabolism in mutant Kirsten rat sarcoma viral oncogene homolog (KRAS) PDA sensitizes cell lines and tumors to ß-lapachone (ß-lap, clinical form ARQ761). ß-Lap is an NADPH:quinone oxidoreductase (NQO1)-bioactivatable drug that leads to NADPH depletion through high levels of reactive oxygen species (ROS) from the futile redox cycling of the drug and subsequently nicotinamide adenine dinucleotide (NAD)+ depletion through poly(ADP ribose) polymerase (PARP) hyperactivation. NQO1 expression is highly activated by mutant KRAS signaling. As such, ß-lap treatment concurrent with inhibition of glutamine metabolism in mutant KRAS, NQO1 overexpressing PDA leads to massive redox imbalance, extensive DNA damage, rapid PARP-mediated NAD+ consumption, and PDA cell death—features not observed in NQO1-low, wild-type KRAS expressing cells.ConclusionsThis treatment strategy illustrates proof of principle that simultaneously decreasing glutamine metabolism-dependent tumor anti-oxidant defenses and inducing supra-physiological ROS formation are tumoricidal and that this rationally designed combination strategy lowers the required doses of both agents in vitro and in vivo. The non-overlapping specificities of GLS1 inhibitors and ß-lap for PDA tumors afford high tumor selectivity, while sparing normal tissue.

中文翻译：

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靶向谷氨酰胺代谢使胰腺癌对β-拉帕酮诱导的 PARP 驱动的代谢灾难敏感

背景胰腺导管腺癌 (PDA) 激活细胞溶质烟酰胺腺嘌呤二核苷酸磷酸 (NADPH) 生产的谷氨酰胺依赖性途径，以维持氧化还原稳态并支持增殖。参与该途径的酶（GLS1（线粒体谷氨酰胺酶 1）、GOT1（细胞质谷氨酸草酰乙酸转氨酶 1）和 GOT2（线粒体谷氨酸草酰乙酸转氨酶 2））在 PDA 中高度上调，其中最近在临床中部署了 GLS1 抑制剂针对合成代谢谷氨酰胺代谢的试验。然而，该途径的单药抑制是细胞抑制的，不太可能在控制晚期疾病方面提供持久的益处。 结果在这里，我们报告说，通过遗传或药理学（bis-2-(5-phenylacetamido-1,2, 4-噻二唑-2-基）乙基硫化物（BPTES）或CB-839）抑制突变型Kirsten大鼠肉瘤病毒癌基因同源物（KRAS）PDA中的谷氨酰胺代谢使细胞系和肿瘤对β-拉帕酮（β-lap，临床形式ARQ761）敏感）。ß-Lap 是一种 NADPH:醌氧化还原酶 (NQO1)-生物可激活药物，通过药物无效氧化还原循环产生的高水平活性氧 (ROS) 导致 NADPH 消耗，随后通过多聚体消耗烟酰胺腺嘌呤二核苷酸 (NAD)+ (ADP 核糖) 聚合酶 (PARP) 过度活化。NQO1 表达被突变的 KRAS 信号高度激活。因此，β-lap 治疗同时抑制突变 KRAS 中的谷氨酰胺代谢，NQO1 过表达 PDA 导致大规模氧化还原失衡、广泛的 DNA 损伤、PARP 介导的 NAD+ 快速消耗，和 PDA 细胞死亡——在 NQO1 低的野生型 KRAS 表达细胞中未观察到的特征。这种合理设计的组合策略降低了体外和体内两种药物所需的剂量。GLS1 抑制剂和 ß-lap 对 PDA 肿瘤的非重叠特异性提供了高肿瘤选择性，同时保留了正常组织。结论该治疗策略证明了同时降低依赖于谷氨酰胺代谢的肿瘤抗氧化防御和诱导超生理 ROS 形成具有杀灭肿瘤作用的原理，并且这种合理设计的组合策略降低了体外和体内两种药物的所需剂量。GLS1 抑制剂和 ß-lap 对 PDA 肿瘤的非重叠特异性提供了高肿瘤选择性，同时保留了正常组织。结论该治疗策略证明了同时降低谷氨酰胺代谢依赖的肿瘤抗氧化防御和诱导超生理 ROS 形成具有杀瘤作用，并且这种合理设计的组合策略降低了体外和体内两种药物的所需剂量。GLS1 抑制剂和 ß-lap 对 PDA 肿瘤的非重叠特异性提供了高肿瘤选择性，同时保留了正常组织。