Quantitative metabolome analysis profiles activation of glutaminolysis in glioma with IDH1 mutation
Quantitative metabolome analysis profiles activation of glutaminolysis in glioma with IDH1 mutation
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DOI：
10.1007/s13277-014-1784-5
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发表时间：
2014-06-01
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影响因子：
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通讯作者：
Natsume, Atsushi
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文献类型：
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作者：
Ohka, Fumiharu;Ito, Maki;Natsume, Atsushi
异柠檬酸脱氢酶 1 (IDH1) 定位于细胞质和过氧化物酶体，催化异柠檬酸氧化脱羧为 α-酮戊二酸 (α-KG)，同时将 NADP(+) 转化为 NADPH。 IDH1 突变常见于 2-4 级神经胶质瘤和急性髓系白血病 (AML)。 IDH1 的突变已在密码子 132 处被发现，在大多数情况下精氨酸被组氨酸取代。突变体 IDH1 获得了新的酶活性，可将 α-KG 转化为 d-2-羟基戊二酸 (2-HG)，后者充当 α-KG 的竞争性抑制剂。结果，α-KG依赖性酶的活性降低。基于这些发现，2-HG 被认为是一种肿瘤代谢物。在本研究中，我们建立了稳定表达 IDH1-WT 和 IDH1-R132H 的 HEK293 和 U87 细胞，并研究了 6-diazo-5-oxo-l-norleucine (DON) 抑制谷氨酰胺酶对细胞增殖的影响。我们发现 IDH1-R132H 细胞的细胞增殖受到抑制。添加α-KG可恢复细胞增殖。使用毛细管电泳飞行时间质谱 (CE-TOFMS) 进行整体代谢组分析，检查了 33 例具有野生型 IDH1 (IDH1-WT) 和 IDH1-R132H 突变的神经胶质瘤的代谢特征。我们发现，在 IDH1-R132H 突变的神经胶质瘤中，2-HG 水平高度升高。有趣的是，在具有 IDH1-R132H 的神经胶质瘤中，谷氨酰胺和谷氨酸水平显着降低，这意味着通过谷氨酰胺分解补充 α-KG。基于这些结果，我们得出结论，谷氨酰胺分解在 IDH1-R132H 突变的神经胶质瘤中被激活，并且有必要开发针对激活的谷氨酰胺分解的新治疗方法。
Isocitrate dehydrogenase 1 (IDH1), which localizes to the cytosol and peroxisomes, catalyzes the oxidative decarboxylation of isocitrate to alpha-ketoglutarate (alpha-KG) and in parallel converts NADP(+) to NADPH. IDH1 mutations are frequently detected in grades 2-4 gliomas and in acute myeloid leukemias (AML). Mutations of IDH1 have been identified at codon 132, with arginine being replaced with histidine in most cases. Mutant IDH1 gains novel enzyme activity converting alpha-KG to d-2-hydroxyglutarate (2-HG) which acts as a competitive inhibitor of alpha-KG. As a result, the activity of alpha-KG-dependent enzyme is reduced. Based on these findings, 2-HG has been proposed to be an oncometabolite. In this study, we established HEK293 and U87 cells that stably expressed IDH1-WT and IDH1-R132H and investigated the effect of glutaminase inhibition on cell proliferation with 6-diazo-5-oxo-l-norleucine (DON). We found that cell proliferation was suppressed in IDH1-R132H cells. The addition of alpha-KG restored cell proliferation. The metabolic features of 33 gliomas with wild type IDH1 (IDH1-WT) and with IDH1-R132H mutation were examined by global metabolome analysis using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). We showed that the 2-HG levels were highly elevated in gliomas with IDH1-R132H mutation. Intriguingly, in gliomas with IDH1-R132H, glutamine and glutamate levels were significantly reduced which implies replenishment of alpha-KG by glutaminolysis. Based on these results, we concluded that glutaminolysis is activated in gliomas with IDH1-R132H mutation and that development of novel therapeutic approaches targeting activated glutaminolysis is warranted.