title: Intermediary metabolite precursor dimethyl-2-ketoglutarate stabilizes hypoxia-inducible factor-1α by inhibiting prolyl-4-hydroxylase PHD2.
abstract: Hypoxia-inducible factor 1α (HIF-1α), a major mediator of tumor physiology, is activated during tumor progression, and its abundance is correlated with therapeutic resistance in a broad range of solid tumors. The accumulation of HIF-1α is mainly caused by hypoxia or through the mutated succinate dehydrogenase A (SDHA) or fumarate hydratase (FH) expression to inhibit its degradation. However, its activation under normoxic conditions, termed pseudohypoxia, in cells without mutated SDHA or FH is not well documented. Here, we show that dimethyl-2-ketoglutarate (DKG), a cell membrane-permeable precursor of a key metabolic intermediate, α-ketoglutarate (α-KG), known for its ability to rescue glutamine deficiency, transiently stabilized HIF-1α by inhibiting activity of the HIF prolyl hydroxylase domain-containing protein, PHD2. Consequently, prolonged DKG-treatment under normoxia elevated HIF-1α abundance and up-regulated the expression of its downstream target genes, thereby inducing a pseudohypoxic condition. This HIF-1α stabilization phenotype is similar to that from treatment of cells with desferrioxamine (DFO), an iron chelator, or dimethyloxalyglycine (DMOG), an established PHD inhibitor, but was not recapitulated with other α-KG analogues, such as Octyl-2KG, MPTOM001 and MPTOM002. Our study is the first example of an α-KG precursor to increase HIF-1α abundance and activity. We propose that DKG acts as a potent HIF-1α activator, highlighting the potential use of DKG to investigate the contribution of PHD2-HIF-1α pathway to tumor biology.
authors.affiliation: Department of Molecular Pharmacology, Beckman Research Institute, City of Hope, Duarte, California, United States of America; Department of Oncology, Fujian Medical University Union Hospital, Fuzhou, Fujian, China; Fujian Key Laboratory of Translational Cancer Medicine, Fuzhou, Fujian, China.
authors.forename: Peifeng
authors.initials: P
authors.lastname: Hou
authors.affiliation: Department of Molecular Pharmacology, Beckman Research Institute, City of Hope, Duarte, California, United States of America; Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute, City of Hope, Duarte, California, United States of America.
authors.forename: Ching-Ying
authors.initials: CY
authors.lastname: Kuo
authors.affiliation: Department of Molecular Pharmacology, Beckman Research Institute, City of Hope, Duarte, California, United States of America; Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute, City of Hope, Duarte, California, United States of America.
authors.forename: Chun-Ting
authors.initials: CT
authors.lastname: Cheng
authors.affiliation: School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan.
authors.forename: Jing-Ping
authors.initials: JP
authors.lastname: Liou
authors.affiliation: Department of Molecular Pharmacology, Beckman Research Institute, City of Hope, Duarte, California, United States of America; Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute, City of Hope, Duarte, California, United States of America.
authors.forename: David K
authors.initials: DK
authors.lastname: Ann
authors.affiliation: Department of Oncology, Fujian Medical University Union Hospital, Fuzhou, Fujian, China; Fujian Key Laboratory of Translational Cancer Medicine, Fuzhou, Fujian, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Chen
mesh_terms: D000600:Amino Acids, Dicarboxylic / Q000494:pharmacology; D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D003676:Deferoxamine / Q000494:pharmacology; D015870:Gene Expression / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D006900:Hydroxylation / Q000187:drug effects; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000494:pharmacology; D007656:Ketoglutaric Acids / Q000494:pharmacology*; D061986:MCF-7 Cells; D011392:Proline / Q000378:metabolism; D059748:Proteolysis / Q000187:drug effects; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000600:Amino Acids, Dicarboxylic; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007502:Iron Chelating Agents; D007656:Ketoglutaric Acids; C550691:dimethyl-2-oxoglutarate; D011392:Proline; C490190:EGLN1 protein, human; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases; D003676:Deferoxamine; C040947:oxalylglycine