Glutaminase inhibitor CB-839 increases radiation sensitivity of lung tumor cells and human lung tumor xenografts in mice
Glutaminase inhibitor CB-839 increases radiation sensitivity of lung tumor cells and human lung tumor xenografts in mice
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DOI：
10.1080/09553002.2018.1558299
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发表时间：
2019-04-01
影响因子：
2.6
通讯作者：
Griffin, Robert J.
中科院分区：
文献类型：
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作者：
Boysen, Gunnar;Jamshidi-Parsian, Azemat;Griffin, Robert J.
目的：本研究的目的是将我们的体外治疗方法转化为体内模型。已知谷氨酰胺摄取增加会驱动癌细胞增殖，使肿瘤细胞具有谷氨酰胺依赖性。研究含有恶性肺肿瘤细胞的淋巴结抽吸物显示谷氨酰胺消耗和谷胱甘肽（GSH）排泄之间存在很强的相关性。随后对A549和H460肺肿瘤细胞系的实验为谷氨酰胺在驱动GSH合成和排泄中的作用提供了额外的证据。使用稳定同位素标记的谷氨酰胺作为示踪代谢物，我们证明了GSH中的谷氨酸基团直接来自谷氨酰胺，将谷氨酰胺的利用与GSH合成密切相关。材料与方法：为了了解谷氨酰胺消耗和GSH排泄之间可能的机制联系，我们更详细地研究了GSH代谢。BPTES是一种谷氨酰胺酶（GLS）特异性抑制剂，用BPTES抑制GLS可有效地阻断GSH的合成和排泄。自从我们以前的工作以来，出现了几种新的GLS抑制剂，我们在此报告了CB-839在A427、H460和A549肺肿瘤细胞和小鼠人肺肿瘤异种移植物中的作用。结果如下：GLS的抑制显著降低了细胞活力，在A427、A549和H460中，抑制集落形成的ED 50值分别为9、27和217 nM。GLS的抑制伴随着对辐射的反应增加30%，这表明谷氨酰胺衍生的GSH在保护肿瘤细胞免受辐射诱导的损伤中具有重要作用。在随后的小鼠异种移植物中，短期CB-839治疗使血清GSH降低>50%，并使H460衍生的肿瘤异种移植物对放射治疗的反应增加30%。结论：这些结果支持GLS活性和GSH合成之间的机制联系，并表明GLS抑制剂是有效的放射增敏剂。
Purpose: The purpose of this study was to translate our in vitro therapy approach to an in vivo model. Increased glutamine uptake is known to drive cancer cell proliferation, making tumor cells glutamine-dependent. Studying lymph-node aspirates containing malignant lung tumor cells showed a strong correlation between glutamine consumption and glutathione (GSH) excretion. Subsequent experiments with A549 and H460 lung tumor cell lines provided additional evidence for glutamine's role in driving synthesis and excretion of GSH. Using stable-isotope-labeled glutamine as a tracer metabolite, we demonstrated that the glutamate group in GSH is directly derived from glutamine, linking glutamine utilization intimately to GSH syntheses. Materials and methods: To understand the possible mechanistic link between glutamine consumption and GSH excretion, we studied GSH metabolism in more detail. Inhibition of glutaminase (GLS) with BPTES, a GLS-specific inhibitor, effectively abolished GSH synthesis and excretion. Since our previous work, several novel GLS inhibitors became available and we report herein effects of CB-839 in A427, H460 and A549 lung tumor cells and human lungtumor xenografts in mice. Results: Inhibition of GLS markedly reduced cell viability, producing ED50 values for inhibition of colony formation of 9, 27 and 217 nM in A427, A549 and H460, respectively. Inhibition of GLS is accompanied by similar to 30% increased response to radiation, suggesting an important role of glutamine-derived GSH in protecting tumor cells against radiation-induced injury. In subsequent mouse xenografts, short-term CB-839 treatments reduced serum GSH by >50% and increased response to radiotherapy of H460-derived tumor xenografts by 30%. Conclusion: The results support the proposed mechanistic link between GLS activity and GSH synthesis and suggest that GLS inhibitors are effective radiosensitizers.