title: Oncometabolic mutation IDH1 R132H confers a metformin-hypersensitive phenotype.
abstract: Metabolic flexibility might be particularly constrained in tumors bearing mutations in isocitrate dehydrogenase 1 (IDH1) leading to the production of the oncometabolite 2-hydroxygluratate (2HG). To test the hypothesis that IDH1 mutations could generate metabolic vulnerabilities for therapeutic intervention, we utilized an MCF10A cell line engineered with an arginine-to-histidine conversion at position 132 (R132H) in the catalytic site of IDH1, which equips the enzyme with a neomorphic α-ketoglutarate to 2HG reducing activity in an otherwise isogenic background. IDH1 R132H/+ and isogenic IDH1 +/+ parental cells were screened for their ability to generate energy-rich NADH when cultured in a standardized high-throughput Phenotype MicroArrayplatform comprising >300 nutrients. A radical remodeling of the metabotype occurred in cells carrying the R132H mutation since they presented a markedly altered ability to utilize numerous carbon catabolic fuels. A mitochondria toxicity-screening modality confirmed a severe inability of IDH1-mutated cells to use various carbon substrates that are fed into the electron transport chain at different points. The mitochondrial biguanide poisons, metformin and phenformin, further impaired the intrinsic weakness of IDH1-mutant cells to use certain carbon-energy sources. Additionally, metabolic reprogramming of IDH1-mutant cells increased their sensitivity to metformin in assays of cell proliferation, clonogenic potential, and mammosphere formation. Targeted metabolomics studies revealed that the ability of metformin to interfere with the anaplerotic entry of glutamine into the tricarboxylic acid cycle could explain the hypersensitivity of IDH1-mutant cells to biguanides. Moreover, synergistic interactions occurred when metformin treatment was combined with the selective R132H-IDH1 inhibitor AGI-5198. Together, these results suggest that therapy involving the simultaneous targeting of metabolic vulnerabilities with metformin, and 2HG overproduction with mutant-selective inhibitors (AGI-5198-related AG-120 [Agios]), might represent a worthwhile avenue of exploration in the treatment of IDH1-mutated tumors.
authors.affiliation: Metabolism and Cancer Group, Translational Research Laboratory, Catalan Institute of Oncology (ICO), Girona, Catalonia, Spain.|Molecular Oncology Group, Girona Biomedical Research Institute (IDIBGI), Girona, Catalonia, Spain.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Cuyàs
authors.affiliation: Unitat de Recerca Biomèdica (URB-CRB), Institut d'Investigació Sanitaria Pere i Virgili (IISPV), Universitat Rovira i Virgili, Reus, Catalonia. Spain.
authors.forename: Salvador
authors.initials: S
authors.lastname: Fernández-Arroyo
authors.affiliation: Metabolism and Cancer Group, Translational Research Laboratory, Catalan Institute of Oncology (ICO), Girona, Catalonia, Spain.|Molecular Oncology Group, Girona Biomedical Research Institute (IDIBGI), Girona, Catalonia, Spain.
authors.forename: Bruna
authors.initials: B
authors.lastname: Corominas-Faja
authors.affiliation: Unitat de Recerca Biomèdica (URB-CRB), Institut d'Investigació Sanitaria Pere i Virgili (IISPV), Universitat Rovira i Virgili, Reus, Catalonia. Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Rodríguez-Gallego
authors.affiliation: Molecular Oncology Group, Girona Biomedical Research Institute (IDIBGI), Girona, Catalonia, Spain.|Medical Oncology, Catalan Institute of Oncology (ICO), Girona, Catalonia, Spain.
authors.forename: Joaquim
authors.initials: J
authors.lastname: Bosch-Barrera
authors.affiliation: Molecular Oncology Group, Girona Biomedical Research Institute (IDIBGI), Girona, Catalonia, Spain.|Clinical Research Unit, Catalan Institute of Oncology (ICO), Girona, Catalonia, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Martin-Castillo
authors.affiliation: Biochemistry and Molecular Biology Unit, Department of Biology, University of Girona, Girona, Catalonia, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: De Llorens
authors.affiliation: Unitat de Recerca Biomèdica (URB-CRB), Institut d'Investigació Sanitaria Pere i Virgili (IISPV), Universitat Rovira i Virgili, Reus, Catalonia. Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Joven
authors.affiliation: Metabolism and Cancer Group, Translational Research Laboratory, Catalan Institute of Oncology (ICO), Girona, Catalonia, Spain.|Molecular Oncology Group, Girona Biomedical Research Institute (IDIBGI), Girona, Catalonia, Spain.
authors.forename: Javier A
authors.initials: JA
authors.lastname: Menendez
mesh_terms: D001932:Brain Neoplasms / Q000235:genetics*; D045744:Cell Line, Tumor; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000235:genetics*; D008687:Metformin / Q000378:metabolism*; D050505:Mutant Proteins / Q000235:genetics*; D009154:Mutation; D010641:Phenotype
chemical_list: D050505:Mutant Proteins; D008687:Metformin; D007521:Isocitrate Dehydrogenase
keywords: IDH1; anaplerosis; cancer; metformin; oncometabolites