Abstract 3732: Characterization of tumor relevant isocitrate dehydrogenase 1 (IDH1)

Abstract

Abstract Isocitrate dehydrogenase 1 (IDH1) is found commonly mutated in grade II and III gliomas and secondary glioblastomas. Normally, IDH1 catalyzes the conversion of isocitrate and NADP+ to α-ketoglutarate and NADPH. However, in mutated form, IDH1 catalyzes α-ketoglutarate and NADPH into NADP+ and D-2-hydroxyglutarate, an oncometabolite. D-2-hydroxyglutarate is toxic to cells and drives a number of pro-tumorigenic pathways. To understand the molecular mechanisms of how mutated IDH1 can lead to brain cancer, we created point mutations in IDH1 to understand the effects on enzyme activity. Site-directed mutagenesis was used to generate mutations at residue 132, the most common site of mutations in cancer patients. Wild type (WT) IDH1 and mutant IDH1 were heterologously expressed in bacteria . Following purification using affinity column chromatography, steady-state kinetic assays were used to compare the catalytic activity of WT versus mutant IDH1. By elucidating the types of mutations at R132 that facilitate D2HG production, we can have a better understanding of how IDH1 mutations affect prognosis and therapeutic response. This work was funded by a Research Scholar Grant, RSG-19-075-01-TBE, from the American Cancer Society (CDS), National Institutes of Health R00 CA187594 (CDS), National Institutes of Health U54CA132384 (SDSU) & U54CA132379 (UC San Diego), MARC 5T34GM008303 (SDSU), and IMSD 5R25GM058906 (SDSU), and the California Metabolic Research Foundation (SDSU). Citation Format: Nalani J. Coleman, Ella Thornberg, Danielle Caliger, Lucas Luna, Christal D. Sohl. Characterization of tumor relevant isocitrate dehydrogenase 1 (IDH1) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3732.