Abstract 1280 A Novel Genetically Encoded Fluorescent Sensor Enables Cellular and Clinical Measurements of D-2-Hydroxyglutarate

D-2-Hydroxyglutarate (D-2-HG) is an oncometabolite that accumulates in response to certain mutations in isocitrate dehydrogenase 1 or 2 (IDH1/2). While D-2-HG is often used as a surrogate marker for IDH1/2 mutant cancers, 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. This work was supported by the Upper Michigan Brain Tumor Center and the CHSPS grant (College of Health Sciences and Professional Studies) at Northern Michigan University.