Abstract SY43-01: Stereochemistry matters: L-2HG as a tumor response to hypoxia

Abstract

Abstract Somatic mutations in isocitrate dehydrogenase 1 or 2 (IDH1/2) contribute to the pathogenesis of cancer via production of the ‘oncometabolite’ D-2-hydroxyglutarate (D-2HG). Elevated D-2HG can block differentiation of malignant cells by functioning as a competitive inhibitor of alpha-ketoglutarate (alpha-KG) dependent enzymes, including Jumonji family histone lysine demethylases. 2HG is a chiral molecule that can exist in either the D- or L- enantiomer. Although cancer-associated IDH1/2 mutations exclusively produce D-2HG, biochemical studies have demonstrated that L-2HG functions as a more potent inhibitor of alpha-KG-dependent enzymes. Here we report that under conditions of oxygen limitation, mammalian cells selectively produce L-2HG via enzymatic reduction of alpha-KG. Hypoxia-induced L-2HG is not mediated by IDH1 or IDH2, but instead results from promiscuous substrate usage by lactate dehydrogenase A (LDHA). During hypoxia, the resulting increase in L-2HG is necessary and sufficient for the induction of increased methylation of histone repressive marks, including histone 3 lysine 9 (H3K9me3). Thus, L-2HG appears to function as a metabolic signaling intermediate, translating information about oxygen availability into epigenetic modifications that can influence gene expression and cellular differentiation. Citation Format: Craig B. Thompson, Andrew M. Intlekofer, Raymond G. Dematteo, Sriram Venneti, Lydia W. S. Finley, Chao Lu, Ariën S. Rustenburg, Patrick B. Grinaway, John D. Chodera, Justin R. Cross, Alexander R. Judkins. Stereochemistry matters: L-2HG as a tumor response to hypoxia. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr SY43-01. doi:10.1158/1538-7445.AM2015-SY43-01