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Stegmann KM, Dickmanns A, Gerber S, Nikolova V, Klemke L, Manzini V, Schlösser D, Bierwirth C, Freund J, Sitte M, Lugert R, Salinas G, Meister TL, Pfaender S, Görlich D, Wollnik B, Groß U, Dobbelstein M. The folate antagonist methotrexate diminishes replication of the coronavirus SARS-CoV-2 and enhances the antiviral efficacy of remdesivir in cell culture models. Virus Res 2021; 302:198469. [PMID: 34090962 PMCID: PMC8180352 DOI: 10.1016/j.virusres.2021.198469] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 12/19/2022]
Abstract
The search for successful therapies of infections with the coronavirus SARS-CoV-2 is ongoing. We tested inhibition of host cell nucleotide synthesis as a promising strategy to decrease the replication of SARS-CoV-2-RNA, thus diminishing the formation of virus progeny. Methotrexate (MTX) is an established drug for cancer therapy and to induce immunosuppression. The drug inhibits dihydrofolate reductase and other enzymes required for the synthesis of nucleotides. Strikingly, the replication of SARS-CoV-2 was inhibited by MTX in therapeutic concentrations around 1 µM, leading to more than 1000-fold reductions in virus progeny in Vero C1008 (Vero E6) and ~100-fold reductions in Calu-3 cells. Virus replication was more sensitive to equivalent concentrations of MTX than of the established antiviral agent remdesivir. MTX strongly diminished the synthesis of viral structural proteins and the amount of released virus RNA. Virus replication and protein synthesis were rescued by folinic acid (leucovorin) and also by inosine, indicating that purine depletion is the principal mechanism that allows MTX to reduce virus RNA synthesis. The combination of MTX with remdesivir led to synergistic impairment of virus replication, even at 100 nM MTX. The use of MTX in treating SARS-CoV-2 infections still awaits further evaluation regarding toxicity and efficacy in infected organisms, rather than cultured cells. Within the frame of these caveats, however, our results raise the perspective of a two-fold benefit from repurposing MTX for treating COVID-19. Firstly, its previously known ability to reduce aberrant inflammatory responses might dampen respiratory distress. In addition, its direct antiviral activity described here would limit the dissemination of the virus.
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Affiliation(s)
- Kim M Stegmann
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany
| | - Antje Dickmanns
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany
| | - Sabrina Gerber
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany
| | - Vella Nikolova
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany
| | - Luisa Klemke
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany
| | - Valentina Manzini
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany
| | - Denise Schlösser
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany
| | - Cathrin Bierwirth
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany
| | - Julia Freund
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany
| | - Maren Sitte
- NGS Integrative Genomics Core Unit, Institute of Human Genetics, University Medical Center Göttingen, Germany
| | - Raimond Lugert
- Institute of Medical Microbiology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany
| | - Gabriela Salinas
- NGS Integrative Genomics Core Unit, Institute of Human Genetics, University Medical Center Göttingen, Germany
| | - Toni Luise Meister
- Department of Molecular and Medical Virology, Ruhr University Bochum, Germany
| | - Stephanie Pfaender
- Department of Molecular and Medical Virology, Ruhr University Bochum, Germany
| | - Dirk Görlich
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Bernd Wollnik
- Institute of Human Genetics, University Medical Center Göttingen, Germany
| | - Uwe Groß
- Institute of Medical Microbiology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany
| | - Matthias Dobbelstein
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Germany.
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Li H, Li Q, Zhang Y, Liu W, Gu B, Narumi T, Siu KL, Youn JY, Liu P, Yang X, Cai H. Novel Treatment of Hypertension by Specifically Targeting E2F for Restoration of Endothelial Dihydrofolate Reductase and eNOS Function Under Oxidative Stress. Hypertension 2019; 73:179-189. [PMID: 30571557 DOI: 10.1161/hypertensionaha.118.11643] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have shown that hydrogen peroxide (H2O2) downregulates tetrahydrobiopterin salvage enzyme DHFR (dihydrofolate reductase) to result in eNOS (endothelial NO synthase) uncoupling and elevated blood pressure. Here, we aimed to delineate molecular mechanisms underlying H2O2 downregulation of endothelial DHFR by examining transcriptional pathways hypothesized to modulate DHFR expression and effects on blood pressure regulation of targeting these novel mechanisms. H2O2 dose and time dependently attenuated DHFR mRNA and protein expression and enzymatic activity in endothelial cells. Deletion of E2F-binding sites, but not those of Sp1 (specificity protein 1), abolished H2O2 attenuation of DHFR promoter activity. Overexpression of E2F1/2/3a activated DHFR promoter at baseline and alleviated the inhibitory effect of H2O2 on DHFR promoter activity. H2O2 treatment diminished mRNA and protein expression of E2F1/2/3a, whereas overexpression of E2F isoforms increased DHFR protein levels. Chromatin immunoprecipitation assay indicated direct binding of E2F1/2/3a to the DHFR promoter, which was weakened by H2O2. E2F1 RNA interference attenuated DHFR protein levels, whereas its overexpression elevated tetrahydrobiopterin levels and tetrahydrobiopterin/dihydrobiopterin ratios in vitro and in vivo. In Ang II (angiotensin II)-infused mice, adenovirus-mediated overexpression of E2F1 markedly abrogated blood pressure to control levels, by restoring endothelial DHFR function to improve NO bioavailability and vasorelaxation. Bioinformatic analyses confirmed a positive correlation between E2F1 and DHFR in human endothelial cells and arteries, and downregulation of both by oxidized phospholipids. In summary, endothelial DHFR is downregulated by H2O2 transcriptionally via an E2F-dependent mechanism, and that specifically targeting E2F1/2/3a to restore DHFR and eNOS function may serve as a novel therapeutic option for the treatment of hypertension.
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Affiliation(s)
- Hong Li
- From the Division of Molecular Medicine, Department of Anesthesiology, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles.,Division of Cardiology, Department of Medicine, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles.,Department of Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China (H.L., P.L.)
| | - Qiang Li
- From the Division of Molecular Medicine, Department of Anesthesiology, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles.,Division of Cardiology, Department of Medicine, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles
| | - Yixuan Zhang
- From the Division of Molecular Medicine, Department of Anesthesiology, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles.,Division of Cardiology, Department of Medicine, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles
| | - Wenting Liu
- Department of Integrative Biology and Physiology (W.L., X.Y.), David Geffen School of Medicine, University of California, Los Angeles
| | - Bo Gu
- From the Division of Molecular Medicine, Department of Anesthesiology, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles.,Division of Cardiology, Department of Medicine, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles
| | - Taro Narumi
- From the Division of Molecular Medicine, Department of Anesthesiology, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles.,Division of Cardiology, Department of Medicine, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles
| | - Kin Lung Siu
- From the Division of Molecular Medicine, Department of Anesthesiology, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles.,Division of Cardiology, Department of Medicine, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles
| | - Ji Youn Youn
- From the Division of Molecular Medicine, Department of Anesthesiology, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles.,Division of Cardiology, Department of Medicine, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles
| | - Peiqing Liu
- Department of Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China (H.L., P.L.)
| | - Xia Yang
- Department of Integrative Biology and Physiology (W.L., X.Y.), David Geffen School of Medicine, University of California, Los Angeles
| | - Hua Cai
- From the Division of Molecular Medicine, Department of Anesthesiology, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles.,Division of Cardiology, Department of Medicine, Cardiovascular Research Laboratories (H.L., Q.L., Y.Z., B.G., T.N., K.L.S., J.Y.Y., H.C.), David Geffen School of Medicine, University of California, Los Angeles
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3
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Reeve SM, Si D, Krucinska J, Yan Y, Viswanathan K, Wang S, Holt GT, Frenkel MS, Ojewole AA, Estrada A, Agabiti SS, Alverson JB, Gibson ND, Priestley ND, Wiemer AJ, Donald BR, Wright DL. Toward Broad Spectrum Dihydrofolate Reductase Inhibitors Targeting Trimethoprim Resistant Enzymes Identified in Clinical Isolates of Methicillin Resistant Staphylococcus aureus. ACS Infect Dis 2019; 5:1896-1906. [PMID: 31565920 DOI: 10.1021/acsinfecdis.9b00222] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The spread of plasmid borne resistance enzymes in clinical Staphylococcus aureus isolates is rendering trimethoprim and iclaprim, both inhibitors of dihydrofolate reductase (DHFR), ineffective. Continued exploitation of these targets will require compounds that can broadly inhibit these resistance-conferring isoforms. Using a structure-based approach, we have developed a novel class of ionized nonclassical antifolates (INCAs) that capture the molecular interactions that have been exclusive to classical antifolates. These modifications allow for a greatly expanded spectrum of activity across these pathogenic DHFR isoforms, while maintaining the ability to penetrate the bacterial cell wall. Using biochemical, structural, and computational methods, we are able to optimize these inhibitors to the conserved active sites of the endogenous and trimethoprim resistant DHFR enzymes. Here, we report a series of INCA compounds that exhibit low nanomolar enzymatic activity and potent cellular activity with human selectivity against a panel of clinically relevant TMP resistant (TMPR) and methicillin resistant Staphylococcus aureus (MRSA) isolates.
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Affiliation(s)
- Stephanie M. Reeve
- Department of Pharmaceutical Sciences, University of Connecticut, 69 N. Eagleville Road, Storrs, Connecticut 06269, United States
| | - Debjani Si
- Department of Pharmaceutical Sciences, University of Connecticut, 69 N. Eagleville Road, Storrs, Connecticut 06269, United States
| | - Jolanta Krucinska
- Department of Pharmaceutical Sciences, University of Connecticut, 69 N. Eagleville Road, Storrs, Connecticut 06269, United States
| | - Yongzhao Yan
- Department of Pharmaceutical Sciences, University of Connecticut, 69 N. Eagleville Road, Storrs, Connecticut 06269, United States
| | - Kishore Viswanathan
- Department of Pharmaceutical Sciences, University of Connecticut, 69 N. Eagleville Road, Storrs, Connecticut 06269, United States
| | - Siyu Wang
- Department of Computer Science, Duke University, 308 Research Drive, Durham, North Carolina 27708, United States
- Program in Computational Biology and Bioinformatics, Duke University, 101 Science Drive, Durham, North Carolina 27708, United States
| | - Graham T. Holt
- Department of Computer Science, Duke University, 308 Research Drive, Durham, North Carolina 27708, United States
- Program in Computational Biology and Bioinformatics, Duke University, 101 Science Drive, Durham, North Carolina 27708, United States
| | - Marcel S. Frenkel
- Department of Biochemistry, Duke University Medical Center, 255 Nanaline H. Duke, Durham, North Carolina 27710, United States
| | - Adegoke A. Ojewole
- Department of Computer Science, Duke University, 308 Research Drive, Durham, North Carolina 27708, United States
- Program in Computational Biology and Bioinformatics, Duke University, 101 Science Drive, Durham, North Carolina 27708, United States
| | - Alexavier Estrada
- Department of Pharmaceutical Sciences, University of Connecticut, 69 N. Eagleville Road, Storrs, Connecticut 06269, United States
| | - Sherry S. Agabiti
- Department of Pharmaceutical Sciences, University of Connecticut, 69 N. Eagleville Road, Storrs, Connecticut 06269, United States
| | - Jeremy B. Alverson
- Department of Chemistry, University of Montana, 32 Campus Drive, Missoula, Montana 59812, United States
| | - Nathan D. Gibson
- Department of Chemistry, University of Montana, 32 Campus Drive, Missoula, Montana 59812, United States
| | - Nigel D. Priestley
- Department of Chemistry, University of Montana, 32 Campus Drive, Missoula, Montana 59812, United States
| | - Andrew J. Wiemer
- Department of Pharmaceutical Sciences, University of Connecticut, 69 N. Eagleville Road, Storrs, Connecticut 06269, United States
| | - Bruce R. Donald
- Department of Computer Science, Duke University, 308 Research Drive, Durham, North Carolina 27708, United States
- Department of Biochemistry, Duke University Medical Center, 255 Nanaline H. Duke, Durham, North Carolina 27710, United States
- Department of Chemistry, Duke University, 124 Science Drive, Durham, North Carolina 27708, United States
| | - Dennis L. Wright
- Department of Pharmaceutical Sciences, University of Connecticut, 69 N. Eagleville Road, Storrs, Connecticut 06269, United States
- Department of Chemistry, University of Connecticut, 55 N. Eagleville Road, Storrs, Connecticut 06269, United States
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4
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Shao Y, Tan B, Shi J, Zhou Q. Methotrexate induces astrocyte apoptosis by disrupting folate metabolism in the mouse juvenile central nervous system. Toxicol Lett 2019; 301:146-156. [DOI: 10.1016/j.toxlet.2018.11.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/22/2018] [Accepted: 11/26/2018] [Indexed: 01/23/2023]
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5
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Patel MM, Volkov OA, Leija C, Lemoff A, Phillips MA. A dual regulatory circuit consisting of S-adenosylmethionine decarboxylase protein and its reaction product controls expression of the paralogous activator prozyme in Trypanosoma brucei. PLoS Pathog 2018; 14:e1007404. [PMID: 30365568 PMCID: PMC6221367 DOI: 10.1371/journal.ppat.1007404] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/07/2018] [Accepted: 10/12/2018] [Indexed: 01/12/2023] Open
Abstract
Polyamines are essential for cell growth of eukaryotes including the etiologic agent of human African trypanosomiasis (HAT), Trypanosoma brucei. In trypanosomatids, a key enzyme in the polyamine biosynthetic pathway, S-adenosylmethionine decarboxylase (TbAdoMetDC) heterodimerizes with a unique catalytically-dead paralog called prozyme to form the active enzyme complex. In higher eukaryotes, polyamine metabolism is subject to tight feedback regulation by spermidine-dependent mechanisms that are absent in trypanosomatids. Instead, in T. brucei an alternative regulatory strategy based on TbAdoMetDC prozyme has evolved. We previously demonstrated that prozyme protein levels increase in response to loss of TbAdoMetDC activity. Herein, we show that prozyme levels are under translational control by monitoring incorporation of deuterated leucine into nascent prozyme protein. We furthermore identify pathway factors that regulate prozyme mRNA translation. We find evidence for a regulatory feedback mechanism in which TbAdoMetDC protein and decarboxylated AdoMet (dcAdoMet) act as suppressors of prozyme translation. In TbAdoMetDC null cells expressing the human AdoMetDC enzyme, prozyme levels are constitutively upregulated. Wild-type prozyme levels are restored by complementation with either TbAdoMetDC or an active site mutant, suggesting that TbAdoMetDC possesses an enzyme activity-independent function that inhibits prozyme translation. Depletion of dcAdoMet pools by three independent strategies: inhibition/knockdown of TbAdoMetDC, knockdown of AdoMet synthase, or methionine starvation, each cause prozyme upregulation, providing independent evidence that dcAdoMet functions as a metabolic signal for regulation of the polyamine pathway in T. brucei. These findings highlight a potential regulatory paradigm employing enzymes and pseudoenzymes that may have broad implications in biology. Trypanosoma brucei is a single-celled eukaryotic pathogen and the causative agent of human African trypanosomiasis (HAT). Polyamines are organic polycations that are essential for growth in T. brucei to facilitate protein translation and to maintain redox homeostasis. The pathway is the target of eflornithine, a current frontline therapy for treatment of HAT. Polyamine biosynthetic enzymes are regulated at multiple levels in mammals (e.g. transcription, translation and protein turnover), but in contrast, T. brucei lacks these mechanisms. Instead in T. brucei a central enzyme in polyamine metabolism called AdoMetDC must form a complex with a sister protein (termed a pseudoenzyme) to be active. Herein, we show that cellular levels of this sister protein we call prozyme are in turn feedback regulated by both AdoMetDC and by its reaction product in response to cell treatments that reduce pathway output. This regulatory paradigm highlights how pseudoenzymes can evolve to play an important role in metabolic pathway regulation and in organismal fitness.
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Affiliation(s)
- Manish M. Patel
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Harry Hines Blvd, Dallas, TX, United States of America
| | - Oleg A. Volkov
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Harry Hines Blvd, Dallas, TX, United States of America
| | - Christopher Leija
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Harry Hines Blvd, Dallas, TX, United States of America
| | - Andrew Lemoff
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Harry Hines Blvd, Dallas, TX, United States of America
| | - Margaret A. Phillips
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Harry Hines Blvd, Dallas, TX, United States of America
- * E-mail:
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6
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Whitsett J, Filho AR, Sethumadhavan S, Celinska J, Widlansky M, Vásquez-Vivar J. Human endothelial dihydrofolate reductase low activity limits vascular tetrahydrobiopterin recycling. Free Radic Biol Med 2013; 63:143-50. [PMID: 23707606 PMCID: PMC3748942 DOI: 10.1016/j.freeradbiomed.2013.04.035] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 04/09/2013] [Accepted: 04/27/2013] [Indexed: 11/19/2022]
Abstract
Tetrahydrobiopterin (BH₄) is required for NO synthesis and inhibition of superoxide release from endothelial NO synthase. Clinical trials using BH₄ to treat endothelial dysfunction have produced mixed results. Poor outcomes may be explained by the rapid systemic and cellular oxidation of BH₄. One of the oxidation products of BH₄, 7,8-dihydrobiopterin (7,8-BH₂), is recycled back to BH₄ by dihydrofolate reductase (DHFR). This enzyme is ubiquitously distributed and shows a wide range of activity depending on species-specific factors and cell type. Information about the kinetics and efficiency of BH4 recycling in human endothelial cells receiving BH₄ treatment is lacking. To characterize this reaction, we applied a novel multielectrode coulometric HPLC method that enabled the direct quantification of 7,8-BH₂ and BH₄, which is not possible with fluorescence-based methodologies. We found that basal untreated BH₄ and 7,8-BH₂ concentrations in human endothelial cells (ECs) are lower than in bovine and murine endothelioma cells. Treatment of human ECs with BH₄ transiently increased intracellular BH₄ while accumulating the more stable 7,8-BH₂. This was different from bovine or murine ECs, which resulted in preferential BH₄ increase. Using BH₄ diastereomers, 6S-BH₄ and 6R-BH₄, the narrow contribution of enzymatic DHFR recycling to total intracellular BH₄ was demonstrated. Reduction of 7,8-BH₂ to BH₄ occurs at very slow rates in cells and needs supraphysiological levels of 7,8-BH₂, indicating this reaction is kinetically limited. Activity assays verified that human DHFR has very low affinity for 7,8-BH₂ (DHF7,8-BH₂) and folic acid inhibits 7,8-BH₂ recycling. We conclude that low activity of endothelial DHFR is an important factor limiting the benefits of BH4 therapies, which may be further aggravated by folate supplements.
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Affiliation(s)
- Jennifer Whitsett
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
- Redox Biology Program, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Artur Rangel Filho
- Department of Pathology, Jackson Memorial Hospital, University of Miami Leonard M. Miller School of Medicine, Miami, Florida 33136
| | | | - Joanna Celinska
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Michael Widlansky
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Jeannette Vásquez-Vivar
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
- Redox Biology Program, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
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Yan KH, Lee LM, Hsieh MC, Yan MD, Yao CJ, Chang PY, Chen TL, Chang HY, Cheng AL, Lai GM, Chuang SE. Aspirin antagonizes the cytotoxic effect of methotrexate in lung cancer cells. Oncol Rep 2013; 30:1497-505. [PMID: 23799623 DOI: 10.3892/or.2013.2561] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 05/09/2013] [Indexed: 11/06/2022] Open
Abstract
Methotrexate (MTX) has been widely used for the treatment of cancer and rheumatoid arthritis (RA). Aspirin (ASA) is a non-selective cyclooxygenase (COX) inhibitor that contributes to the treatment of inflammatory conditions such as RA. It has been observed that the antitumor effect of ASA can be attributed to inhibition of cell cycle progression, induction of apoptosis and inhibition of angiogenesis. In the present study, we revealed that the treatment with a combination of MTX and ASA resulted in antagonism of the cytotoxic effect as demonstrated by SRB and colony formation assays. ASA alleviated the MTX-mediated S phase accumulation and recovered the G1 phase. MTX-mediated accumulation of the S phase marker cyclin A was also alleviated by ASA. Notably, FAS protein levels were upregulated by MTX in A549 cells. The antagonism of MTX efficacy caused by ASA was accompanied by altered expression of caspase-3, Bcl-2 and FAS but not dihydrofolate reductase (DHFR). This suggests that the alteration of caspase-3, Bcl-2 and FAS was involved in the antagonism between ASA and MTX. Exogenously added folic acid reversed the MTX-mediated DHFR inhibition following either MTX or MTX + ASA treatments. Most importantly, we demonstrated for the first time that the commonly used non-steroidal anti-inflammatory drug for headache ASA and possibly other COX-1/2 inhibitors can produce a strong antagonistic effect on the growth inhibition of lung cancer cells when administered in combination with MTX. The clinical implication of our finding is obvious, i.e., the clinical efficacy of MTX therapy can be compromised by ASA and their concomitant use should be avoided.
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Affiliation(s)
- Kun-Huang Yan
- Department of Urology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan, R.O.C
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8
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Xiao Y, Nguyen S, Kim SH, Volkov OA, Tu BP, Phillips MA. Product feedback regulation implicated in translational control of the Trypanosoma brucei S-adenosylmethionine decarboxylase regulatory subunit prozyme. Mol Microbiol 2013; 88:846-61. [PMID: 23634831 DOI: 10.1111/mmi.12226] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2013] [Indexed: 12/12/2022]
Abstract
Human African sleeping sickness (HAT) is caused by the parasitic protozoan Trypanosoma brucei. Polyamine biosynthesis is an important drug target in the treatment of HAT. Previously we showed that trypanosomatid S-adenosylmethionine decarboxylase (AdoMetDC), a key enzyme for biosynthesis of the polyamine spermidine, is activated by heterodimer formation with an inactive paralogue termed prozyme. Furthermore, prozyme protein levels were regulated in response to reduced AdoMetDC activity. Herein we show that T. brucei encodes three prozyme transcripts. The 3'UTRs of these transcripts were mapped and chloramphenicol acetyltransferase (CAT) reporter constructs were used to identify a 1.2 kb region that contained a 3'UTR prozyme regulatory element sufficient to upregulate CAT protein levels (but not RNA) upon AdoMetDC inhibition, supporting the hypothesis that prozyme expression is regulated translationally. To gain insight into trans-acting factors, genetic rescue of AdoMetDC RNAi knock-down lines with human AdoMetDC was performed leading to rescue of the cell growth block, and restoration of prozyme protein to wild-type levels. Metabolite analysis showed that prozyme protein levels were inversely proportional to intracellular levels of decarboxylated AdoMet (dcAdoMet). These data suggest that prozyme translation may be regulated by dcAdoMet, a metabolite not previously identified to play a regulatory role.
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Affiliation(s)
- Yanjing Xiao
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9041, USA
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Tomé S, Manley K, Simard JP, Clark GW, Slean MM, Swami M, Shelbourne PF, Tillier ERM, Monckton DG, Messer A, Pearson CE. MSH3 polymorphisms and protein levels affect CAG repeat instability in Huntington's disease mice. PLoS Genet 2013; 9:e1003280. [PMID: 23468640 PMCID: PMC3585117 DOI: 10.1371/journal.pgen.1003280] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 12/12/2012] [Indexed: 01/21/2023] Open
Abstract
Expansions of trinucleotide CAG/CTG repeats in somatic tissues are thought to contribute to ongoing disease progression through an affected individual's life with Huntington's disease or myotonic dystrophy. Broad ranges of repeat instability arise between individuals with expanded repeats, suggesting the existence of modifiers of repeat instability. Mice with expanded CAG/CTG repeats show variable levels of instability depending upon mouse strain. However, to date the genetic modifiers underlying these differences have not been identified. We show that in liver and striatum the R6/1 Huntington's disease (HD) (CAG)∼100 transgene, when present in a congenic C57BL/6J (B6) background, incurred expansion-biased repeat mutations, whereas the repeat was stable in a congenic BALB/cByJ (CBy) background. Reciprocal congenic mice revealed the Msh3 gene as the determinant for the differences in repeat instability. Expansion bias was observed in congenic mice homozygous for the B6 Msh3 gene on a CBy background, while the CAG tract was stabilized in congenics homozygous for the CBy Msh3 gene on a B6 background. The CAG stabilization was as dramatic as genetic deficiency of Msh2. The B6 and CBy Msh3 genes had identical promoters but differed in coding regions and showed strikingly different protein levels. B6 MSH3 variant protein is highly expressed and associated with CAG expansions, while the CBy MSH3 variant protein is expressed at barely detectable levels, associating with CAG stability. The DHFR protein, which is divergently transcribed from a promoter shared by the Msh3 gene, did not show varied levels between mouse strains. Thus, naturally occurring MSH3 protein polymorphisms are modifiers of CAG repeat instability, likely through variable MSH3 protein stability. Since evidence supports that somatic CAG instability is a modifier and predictor of disease, our data are consistent with the hypothesis that variable levels of CAG instability associated with polymorphisms of DNA repair genes may have prognostic implications for various repeat-associated diseases. The genetic instability of repetitive DNA sequences in particular genes can lead to numerous neurodegenerative, neurological, and neuromuscular diseases. These diseases show progressively increasing severity of symptoms through the life of the affected individual, a phenomenon that is linked with increasing instability of the repeated sequences as the person ages. There is variability in the levels of this instability between individuals—the source of this variability is unknown. We have shown in a mouse model of repeat instability that small differences in a certain DNA repair gene, MSH3, whose protein is known to fix broken DNA, can lead to variable levels of repeat instability. These DNA repair variants lead to different repair protein levels, where lower levels lead to reduced repeat instability. Our findings reveal that such naturally occurring variations in DNA repair genes in affected humans may serve as a predictor of disease progression. Moreover, our findings support the concept that pharmacological reduction of MSH3 protein should reduce repeat instability and disease progression.
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Affiliation(s)
- Stéphanie Tomé
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kevin Manley
- Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
- Department of Biomedical Sciences, University at Albany, SUNY, Albany, New York, United States of America
| | - Jodie P. Simard
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Greg W. Clark
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Institute for Cancer Research, Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada
| | - Meghan M. Slean
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Meera Swami
- Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Peggy F. Shelbourne
- Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Elisabeth R. M. Tillier
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Institute for Cancer Research, Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada
| | - Darren G. Monckton
- Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Anne Messer
- Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
- Department of Biomedical Sciences, University at Albany, SUNY, Albany, New York, United States of America
| | - Christopher E. Pearson
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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Hsieh YC, Tedeschi P, Adebisi Lawal R, Banerjee D, Scotto K, Kerrigan JE, Lee KC, Johnson-Farley N, Bertino JR, Abali EE. Enhanced degradation of dihydrofolate reductase through inhibition of NAD kinase by nicotinamide analogs. Mol Pharmacol 2012. [PMID: 23197646 DOI: 10.1124/mol.112.080218] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Dihydrofolate reductase (DHFR), because of its essential role in DNA synthesis, has been targeted for the treatment of a wide variety of human diseases, including cancer, autoimmune diseases, and infectious diseases. Methotrexate (MTX), a tight binding inhibitor of DHFR, is one of the most widely used drugs in cancer treatment and is especially effective in the treatment of acute lymphocytic leukemia, non-Hodgkin's lymphoma, and osteosarcoma. Limitations to its use in cancer include natural resistance and acquired resistance due to decreased cellular uptake and decreased retention due to impaired polyglutamylate formation and toxicity at higher doses. Here, we describe a novel mechanism to induce DHFR degradation through cofactor depletion in neoplastic cells by inhibition of NAD kinase, the only enzyme responsible for generating NADP, which is rapidly converted to NADPH by dehydrogenases/reductases. We identified an inhibitor of NAD kinase, thionicotinamide adenine dinucleotide phosphate (NADPS), which led to accelerated degradation of DHFR and to inhibition of cancer cell growth. Of importance, combination treatment of NADPS with MTX displayed significant synergy in a metastatic colon cancer cell line and was effective in a MTX-transport resistant leukemic cell line. We suggest that NAD kinase is a valid target for further inhibitor development for cancer treatment.
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Affiliation(s)
- Yi-Ching Hsieh
- Departments of Pharmacology and Medicine, Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, New Jersey, USA
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11
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Aye Y, Long MJC, Stubbe J. Mechanistic studies of semicarbazone triapine targeting human ribonucleotide reductase in vitro and in mammalian cells: tyrosyl radical quenching not involving reactive oxygen species. J Biol Chem 2012; 287:35768-35778. [PMID: 22915594 DOI: 10.1074/jbc.m112.396911] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Triapine® (3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP)) is a drug in Phase II trials. One of its established cellular targets is the β(2) subunit of ribonucleotide reductase that requires a diferric-tyrosyl-radical [(Fe(III)(2)-Y·)(Fe(III)(2))] cofactor for de novo DNA biosynthesis. Several mechanisms for 3-AP inhibition of β(2) have been proposed; one involves direct iron chelation from β(2), whereas a second involves Y· destruction by reactive oxygen species formed in situ in the presence of O(2) and reductant by Fe(II)-(3-AP). Inactivation of β(2) can thus arise from cofactor destruction by loss of iron or Y·. In vitro kinetic data on the rates of (55)Fe and Y· loss from [((55)Fe(III)(2)-Y·)((55)Fe(III)(2))]-β(2) under aerobic and anaerobic conditions reveal that Y· loss alone is sufficient for rapid β(2) inactivation. Oxyblot(TM) and mass spectrometric analyses of trypsin-digested inhibited β(2), and lack of Y· loss from H(2)O(2) and O(2)(•) treatment together preclude reactive oxygen species involvement in Y· loss. Three mammalian cell lines treated with 5 μm 3-AP reveal Y· loss and β(2) inactivation within 30-min of 3-AP-exposure, analyzed by whole-cell EPR and lysate assays, respectively. Selective degradation of apo- over [(Fe(III)(2)-Y·)(Fe(III)(2))]-β(2) in lysates, similar iron-content in β(2) immunoprecipitated from 3-AP-treated and untreated [(55)Fe]-prelabeled cells, and prolonged (12 h) stability of the inhibited β(2) are most consistent with Y· loss being the predominant mode of inhibition, with β(2) remaining iron-loaded and stable. A model consistent with in vitro and cell-based biochemical studies is presented in which Fe(II)-(3-AP), which can be cycled with reductant, directly reduces Y· of the [(Fe(III)(2)-Y·)(Fe(III)(2))] cofactor of β(2).
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Affiliation(s)
- Yimon Aye
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Marcus J C Long
- Graduate Program in Biochemistry and Biophysics, Brandeis University, Waltham, Massachusetts 02454
| | - JoAnne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.
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