BIOM-85. A NOVEL GENETICALLY ENCODED FLUORESCENT SENSOR ENABLES CELLULAR AND CLINICAL MEASUREMENTS OF D-2-HYDROXYGLUTARATE (D-2-HG)

Abstract D-2-Hydroxyglutarate (D-2-HG) is an oncometabolite produced by mutant isocitrate dehydrogenase 1 or 2 (IDH1/2). D-2-HG is a promising surrogate marker for IDH1/2 mutant cancers; however, simple and enantiomer-specific detection methods are limited. We have developed a genetically encoded fluorescent sensor, D2HGlo, that rapidly detects and quantifies D-2-HG in biological samples, including cell culture media, artificial cerebrospinal fluid, serum, and urine. D2HGlo directly analyzed supernatants from tumor lysates, predicting IDH1 mutational status in gliomas with 100% accuracy. Thus, D2HGlo may be amenable to preoperative or intraoperative detection of IDH1/2 mutations and postoperative monitoring of D-2-HG levels in patients treated with mutant IDH1 inhibitors. Importantly, D2HGlo also performs robustly in situ, where it demonstrates the specific detection of endogenous and exogenous D-2-HG levels at the subcellular level. As no tool currently exists to study the spatial distribution of D-2-HG in living cells, we present novel findings of elevated levels within the nucleus, mitochondria, and cytoplasm of IDH1 mutant cells. These results offer valuable insight into the oncogenic mechanisms driving IDH1/2 mutant cancers and may aid in further elucidation of its role in disease.