In recent years, onco-metabolites like D-2-hydroxyglutarate, which is produced in isocitrate dehydrogenase-mutated tumors, have gained increasing interest. Here, we report a metabolite in human specimens that is closely related to 2-hydroxyglutarate: the intramolecular ester of 2-hydroxyglutarate, 2-hydroxyglutarate-γ-lactone. Using 13C5-L-glutamine tracer analysis, we showed that 2-hydroxyglutarate is the endogenous precursor of 2-hydroxyglutarate-lactone and that there is a high exchange between these two metabolites. Lactone formation does not depend on mutated isocitrate dehydrogenase, but its formation is most probably linked to transport processes across the cell membrane and favored at low environmental pH. Furthermore, human macrophages showed not only striking differences in uptake of 2-hydroxyglutarate and its lactone but also in the enantiospecific hydrolysis of the latter. Consequently, 2-hydroxyglutarate-lactone may play a critical role in the modulation of the tumor microenvironment.
近年来,像D-2-羟基
戊二酸这样的肿瘤代谢产物,它是在
异柠檬酸脱氢酶突变肿瘤中产生的,引起了越来越多的关注。在这里,我们报告了人体标本中与2-羟基
戊二酸密切相关的一种代谢产物:2-羟基
戊二酸的分子内酯,2-羟基
戊二酸-γ-内酯。使用13C5-L-谷
氨酰胺示踪分析,我们表明2-羟基
戊二酸是2-羟基
戊二酸内酯的内源前体,并且这两种代谢产物之间存在高度交换。内酯的形成并不依赖于突变的
异柠檬酸脱氢酶,但其形成很可能与细胞膜之间的转运过程有关,并且在低环境pH下更为有利。此外,人类巨噬细胞不仅在对2-羟基
戊二酸及其内酯的摄取上存在显著差异,而且在对后者的对映选择性
水解上也存在差异。因此,2-羟基
戊二酸内酯可能在调节肿瘤微环境中发挥关键作用。