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Zhang SM, Paulin CB, Shu H, Yagüe-Capilla M, Michel M, Marttila P, Ortis F, Bwanika HC, Dirks C, Venkatram RP, Wiita E, Jemth AS, Almlöf I, Loseva O, Hormann FM, Koolmeister T, Linde E, Lee S, Llona-Minguez S, Haraldsson M, Axelsson H, Strömberg K, Homan EJ, Scobie M, Lundbäck T, Helleday T, Rudd SG. Identification and evaluation of small-molecule inhibitors against the dNTPase SAMHD1 via a comprehensive screening funnel. iScience 2024; 27:108907. [PMID: 38318365 PMCID: PMC10839966 DOI: 10.1016/j.isci.2024.108907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 09/05/2023] [Accepted: 01/10/2024] [Indexed: 02/07/2024] Open
Abstract
SAMHD1 is a dNTP triphosphohydrolase governing nucleotide pool homeostasis and can detoxify chemotherapy metabolites controlling their clinical responses. To understand SAMHD1 biology and investigate the potential of targeting SAMHD1 as neoadjuvant to current chemotherapies, we set out to discover selective small-molecule inhibitors. Here, we report a discovery pipeline encompassing a biochemical screening campaign and a set of complementary biochemical, biophysical, and cell-based readouts for rigorous characterization of the screen output. The identified small molecules, TH6342 and analogs, accompanied by inactive control TH7126, demonstrated specific, low μM potency against both physiological and oncology-drug-derived substrates. By coupling kinetic studies with thermal shift assays, we reveal the inhibitory mechanism of TH6342 and analogs, which engage pre-tetrameric SAMHD1 and deter oligomerization and allosteric activation without occupying nucleotide-binding pockets. Altogether, our study diversifies inhibitory modes against SAMHD1, and the discovery pipeline reported herein represents a thorough framework for future SAMHD1 inhibitor development.
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Affiliation(s)
- Si Min Zhang
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Cynthia B.J. Paulin
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Huazhang Shu
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Miriam Yagüe-Capilla
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Maurice Michel
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Petra Marttila
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Florian Ortis
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Henri Colyn Bwanika
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Christopher Dirks
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Rajagopal Papagudi Venkatram
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Elisée Wiita
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Ann-Sofie Jemth
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Ingrid Almlöf
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Olga Loseva
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Femke M. Hormann
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Tobias Koolmeister
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Erika Linde
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Sun Lee
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Sabin Llona-Minguez
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Martin Haraldsson
- Chemical Biology Consortium Sweden, Science for Life Laboratory (SciLifeLab), Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Hanna Axelsson
- Chemical Biology Consortium Sweden, Science for Life Laboratory (SciLifeLab), Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Kia Strömberg
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Evert J. Homan
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Martin Scobie
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Thomas Lundbäck
- Chemical Biology Consortium Sweden, Science for Life Laboratory (SciLifeLab), Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 65 Stockholm, Sweden
| | - Thomas Helleday
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
- Weston Park Cancer Centre, Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, UK
| | - Sean G. Rudd
- Science for Life Laboratory (SciLifeLab), Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden
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Qi Y, Zhang Y, Tian S, Zong R, Yan X, Wang Y, Wang Y, Zhao J. An optimized prime editing system for efficient modification of the pig genome. SCIENCE CHINA. LIFE SCIENCES 2023; 66:2851-2861. [PMID: 37505431 DOI: 10.1007/s11427-022-2334-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/22/2023] [Indexed: 07/29/2023]
Abstract
Prime editing (PE) is a recent gene editing technology that can mediate insertions or deletions and all twelve types of base-to-base conversions. However, its low efficiency hampers the application in creating novel breeds and biomedical models, especially in pigs and other important farm animals. Here, we demonstrate that the pig genome is editable using the PE system, but the editing efficiency was quite low as expected. Therefore, we aimed to enhance PE efficiency by modulating both exogenous PE tools and endogenous pathways in porcine embryonic fibroblasts (PEFs). First, we modified the pegRNA by extending the duplex length and mutating the fourth thymine in a continuous sequence of thymine bases to cytosine, which significantly enhanced PE efficiency by improving the expression of pegRNA and targeted cleavage. Then, we targeted SAMHD1, a deoxynucleoside triphosphate triphosphohydrolase (dNTPase) that impedes the reverse transcription process in retroviruses, and found that treatment with its inhibitor, cephalosporin C zinc salt (CPC), increased PE efficiency up to 29-fold (4-fold on average), presumably by improving the reverse transcription process of Moloney murine leukemia virus reverse transcriptase (M-MLV RT) in the PE system. Moreover, PE efficiency was obviously improved by treatment with a panel of histone deacetylase inhibitors (HDACis). Among the four HDACis tested, panobinostat was the most efficient, with an efficiency up to 122-fold (7-fold on average), partly due to the considerable HDACi-mediated increase in transgene expression. In addition, the synergistic use of the three strategies further enhanced PE efficiency in PEFs. Our study provides novel approaches for optimization of the PE system and broadens the application scope of PE in agriculture and biomedicine.
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Affiliation(s)
- Yanan Qi
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ying Zhang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101, China
| | - Shuangjie Tian
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ruojun Zong
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xinghui Yan
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yu Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yanfang Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
| | - Jianguo Zhao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China.
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101, China.
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3
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Egleston M, Dong L, Howlader AH, Bhat S, Orris B, Bianchet MA, Greenberg MM, Stivers JT. Deoxyguanosine-Linked Bifunctional Inhibitor of SAMHD1 dNTPase Activity and Nucleic Acid Binding. ACS Chem Biol 2023; 18:2200-2210. [PMID: 37233733 PMCID: PMC10596003 DOI: 10.1021/acschembio.3c00118] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/10/2023] [Indexed: 05/27/2023]
Abstract
Sterile alpha motif histidine-aspartate domain protein 1 (SAMHD1) is a deoxynucleotide triphosphohydrolase that exists in monomeric, dimeric, and tetrameric forms. It is activated by GTP binding to an A1 allosteric site on each monomer subunit, which induces dimerization, a prerequisite for dNTP-induced tetramerization. SAMHD1 is a validated drug target stemming from its inactivation of many anticancer nucleoside drugs leading to drug resistance. The enzyme also possesses a single-strand nucleic acid binding function that promotes RNA and DNA homeostasis by several mechanisms. To discover small molecule inhibitors of SAMHD1, we screened a custom ∼69 000-compound library for dNTPase inhibitors. Surprisingly, this effort yielded no viable hits and indicated that exceptional barriers for discovery of small molecule inhibitors existed. We then took a rational fragment-based inhibitor design approach using a deoxyguanosine (dG) A1 site targeting fragment. A targeted chemical library was synthesized by coupling a 5'-phosphoryl propylamine dG fragment (dGpC3NH2) to 376 carboxylic acids (RCOOH). Direct screening of the products (dGpC3NHCO-R) yielded nine initial hits, one of which (R = 3-(3'-bromo-[1,1'-biphenyl]), 5a) was investigated extensively. Amide 5a is a competitive inhibitor against GTP binding to the A1 site and induces inactive dimers that are deficient in tetramerization. Surprisingly, 5a also prevented ssDNA and ssRNA binding, demonstrating that the dNTPase and nucleic acid binding functions of SAMHD1 can be disrupted by a single small molecule. A structure of the SAMHD1-5a complex indicates that the biphenyl fragment impedes a conformational change in the C-terminal lobe that is required for tetramerization.
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Affiliation(s)
- Matthew Egleston
- Department
of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Linghao Dong
- Department
of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - A. Hasan Howlader
- Department
of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Shridhar Bhat
- Department
of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Benjamin Orris
- Department
of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Mario A. Bianchet
- Department
of Neurology and Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Marc M. Greenberg
- Department
of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - James T. Stivers
- Department
of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
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4
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Song J, Yang RR, Chang J, Liu YD, Lu CH, Chen LF, Guo H, Zhang YH, Fan ZS, Zhou JY, Zhou GZ, Zhang KK, Luo XM, Chen KX, Jiang HL, Zhang SL, Zheng MY. Discovery and characterization of a novel cGAS covalent inhibitor for the treatment of inflammatory bowel disease. Acta Pharmacol Sin 2023; 44:791-800. [PMID: 36229599 PMCID: PMC10043009 DOI: 10.1038/s41401-022-01002-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 09/19/2022] [Indexed: 11/09/2022] Open
Abstract
Cyclic GMP-AMP synthase (cGAS), a cytosolic DNA sensor, acts as a nucleotidyl transferase that catalyzes ATP and GTP to form cyclic GMP-AMP (cGAMP) and plays a critical role in innate immunity. Hyperactivation of cGAS-STING signaling contributes to hyperinflammatory responses. Therefore, cGAS is considered a promising target for the treatment of inflammatory diseases. Herein, we report the discovery and identification of several novel types of cGAS inhibitors by pyrophosphatase (PPiase)-coupled activity assays. Among these inhibitors, 1-(1-phenyl-3,4-dihydro-1H-pyrrolo[1,2-a]pyrazin-2-yl)prop-2-yn-1-one (compound 3) displayed the highest potency and selectivity at the cellular level. Compound 3 exhibited better inhibitory activity and pathway selectivity than RU.521, which is a selective cGAS inhibitor with anti-inflammatory effects in vitro and in vivo. Thermostability analysis, nuclear magnetic resonance and isothermal titration calorimetry assays confirmed that compound 3 directly binds to the cGAS protein. Mass spectrometry and mutation analysis revealed that compound 3 covalently binds to Cys419 of cGAS. Notably, compound 3 demonstrated promising therapeutic efficacy in a dextran sulfate sodium (DSS)-induced mouse colitis model. These results collectively suggest that compound 3 will be useful for understanding the biological function of cGAS and has the potential to be further developed for inflammatory disease therapies.
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Affiliation(s)
- Jia Song
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Rui-Rui Yang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Shanghai Institute for Advanced Immunochemical Studies, and School of Life Science and Technology, Shanghai Tech University, Shanghai, 200031, China
| | - Jie Chang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Ya-Dan Liu
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Cheng-Hao Lu
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Li-Fan Chen
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hao Guo
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ying-Hui Zhang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zi-Sheng Fan
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Jing-Yi Zhou
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Gui-Zhen Zhou
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Ke-Ke Zhang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Xiao-Min Luo
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Kai-Xian Chen
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Hua-Liang Jiang
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China.
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Shanghai Institute for Advanced Immunochemical Studies, and School of Life Science and Technology, Shanghai Tech University, Shanghai, 200031, China.
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Su-Lin Zhang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Ming-Yue Zheng
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
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Helleday T, Rudd SG. Targeting the DNA damage response and repair in cancer through nucleotide metabolism. Mol Oncol 2022; 16:3792-3810. [PMID: 35583750 PMCID: PMC9627788 DOI: 10.1002/1878-0261.13227] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/05/2022] [Accepted: 05/17/2022] [Indexed: 12/24/2022] Open
Abstract
The exploitation of the DNA damage response and DNA repair proficiency of cancer cells is an important anticancer strategy. The replication and repair of DNA are dependent upon the supply of deoxynucleoside triphosphate (dNTP) building blocks, which are produced and maintained by nucleotide metabolic pathways. Enzymes within these pathways can be promising targets to selectively induce toxic DNA lesions in cancer cells. These same pathways also activate antimetabolites, an important group of chemotherapies that disrupt both nucleotide and DNA metabolism to induce DNA damage in cancer cells. Thus, dNTP metabolic enzymes can also be targeted to refine the use of these chemotherapeutics, many of which remain standard of care in common cancers. In this review article, we will discuss both these approaches exemplified by the enzymes MTH1, MTHFD2 and SAMHD1. © 2022 The Authors. Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.
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Affiliation(s)
- Thomas Helleday
- Science for Life LaboratoryDepartment of Oncology‐PathologyKarolinska InstitutetStockholmSweden
- Department of Oncology and Metabolism, Weston Park Cancer CentreUniversity of SheffieldUK
| | - Sean G. Rudd
- Science for Life LaboratoryDepartment of Oncology‐PathologyKarolinska InstitutetStockholmSweden
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6
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Johnston ML, Bonett EM, DeColli AA, Freel Meyers CL. Antibacterial Target DXP Synthase Catalyzes the Cleavage of d-Xylulose 5-Phosphate: a Study of Ketose Phosphate Binding and Ketol Transfer Reaction. Biochemistry 2022; 61:1810-1823. [PMID: 35998648 PMCID: PMC9531112 DOI: 10.1021/acs.biochem.2c00274] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The bacterial enzyme 1-deoxy-d-xylulose 5-phosphate synthase (DXPS) catalyzes the formation of DXP from pyruvate and d-glyceraldehyde 3-phosphate (d-GAP) in a thiamin diphosphate (ThDP)-dependent manner. In addition to its role in isoprenoid biosynthesis, DXP is required for ThDP and pyridoxal phosphate biosynthesis. Due to its function as a branch-point enzyme and its demonstrated substrate and catalytic promiscuity, we hypothesize that DXPS could be key for bacterial adaptation in the dynamic metabolic landscape during infection. Prior work in the Freel Meyers laboratory has illustrated that DXPS displays relaxed specificity toward donor and acceptor substrates and varies acceptor specificity according to the donor used. We have reported that DXPS forms dihydroxyethyl (DHE)ThDP from ketoacid or aldehyde donor substrates via decarboxylation and deprotonation, respectively. Here, we tested other DHE donors and found that DXPS cleaves d-xylulose 5-phosphate (X5P) at C2-C3, producing DHEThDP through a third mechanism involving d-GAP elimination. We interrogated DXPS-catalyzed reactions using X5P as a donor substrate and illustrated (1) production of a semi-stable enzyme-bound intermediate and (2) O2, H+, and d-erythrose 4-phosphate act as acceptor substrates, highlighting a new transketolase-like activity of DXPS. Furthermore, we examined X5P binding to DXPS and suggest that the d-GAP binding pocket plays a crucial role in X5P binding and turnover. Overall, this study reveals a ketose-cleavage reaction catalyzed by DXPS, highlighting the remarkable flexibility for donor substrate usage by DXPS compared to other C-C bond-forming enzymes.
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Affiliation(s)
- Melanie L. Johnston
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Eucolona M. Bonett
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | - Caren L. Freel Meyers
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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7
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Rothenburger T, Thomas D, Schreiber Y, Wratil PR, Pflantz T, Knecht K, Digianantonio K, Temple J, Schneider C, Baldauf HM, McLaughlin KM, Rothweiler F, Bilen B, Farmand S, Bojkova D, Costa R, Ferreirós N, Geisslinger G, Oellerich T, Xiong Y, Keppler OT, Wass MN, Michaelis M, Cinatl J. Differences between intrinsic and acquired nucleoside analogue resistance in acute myeloid leukaemia cells. J Exp Clin Cancer Res 2021; 40:317. [PMID: 34641952 PMCID: PMC8507139 DOI: 10.1186/s13046-021-02093-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/01/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND SAMHD1 mediates resistance to anti-cancer nucleoside analogues, including cytarabine, decitabine, and nelarabine that are commonly used for the treatment of leukaemia, through cleavage of their triphosphorylated forms. Hence, SAMHD1 inhibitors are promising candidates for the sensitisation of leukaemia cells to nucleoside analogue-based therapy. Here, we investigated the effects of the cytosine analogue CNDAC, which has been proposed to be a SAMHD1 inhibitor, in the context of SAMHD1. METHODS CNDAC was tested in 13 acute myeloid leukaemia (AML) cell lines, in 26 acute lymphoblastic leukaemia (ALL) cell lines, ten AML sublines adapted to various antileukaemic drugs, 24 single cell-derived clonal AML sublines, and primary leukaemic blasts from 24 AML patients. Moreover, 24 CNDAC-resistant sublines of the AML cell lines HL-60 and PL-21 were established. The SAMHD1 gene was disrupted using CRISPR/Cas9 and SAMHD1 depleted using RNAi, and the viral Vpx protein. Forced DCK expression was achieved by lentiviral transduction. SAMHD1 promoter methylation was determined by PCR after treatment of genomic DNA with the methylation-sensitive HpaII endonuclease. Nucleoside (analogue) triphosphate levels were determined by LC-MS/MS. CNDAC interaction with SAMHD1 was analysed by an enzymatic assay and by crystallisation. RESULTS Although the cytosine analogue CNDAC was anticipated to inhibit SAMHD1, SAMHD1 mediated intrinsic CNDAC resistance in leukaemia cells. Accordingly, SAMHD1 depletion increased CNDAC triphosphate (CNDAC-TP) levels and CNDAC toxicity. Enzymatic assays and crystallisation studies confirmed CNDAC-TP to be a SAMHD1 substrate. In 24 CNDAC-adapted acute myeloid leukaemia (AML) sublines, resistance was driven by DCK (catalyses initial nucleoside phosphorylation) loss. CNDAC-adapted sublines displayed cross-resistance only to other DCK substrates (e.g. cytarabine, decitabine). Cell lines adapted to drugs not affected by DCK or SAMHD1 remained CNDAC sensitive. In cytarabine-adapted AML cells, increased SAMHD1 and reduced DCK levels contributed to cytarabine and CNDAC resistance. CONCLUSION Intrinsic and acquired resistance to CNDAC and related nucleoside analogues are driven by different mechanisms. The lack of cross-resistance between SAMHD1/ DCK substrates and non-substrates provides scope for next-line therapies after treatment failure.
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Affiliation(s)
- Tamara Rothenburger
- Institute for Medical Virology, Goethe-University, Frankfurt am Main, Germany
- Faculty of Biological Sciences, Goethe-University, Frankfurt am Main, Germany
| | - Dominique Thomas
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University of Frankfurt, Frankfurt, Germany
| | - Yannick Schreiber
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University of Frankfurt, Frankfurt, Germany
| | - Paul R Wratil
- Max von Pettenkofer Institute & Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, LMU München, Munich, Germany
- German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Tamara Pflantz
- Max von Pettenkofer Institute & Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, LMU München, Munich, Germany
- German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Kirsten Knecht
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Katie Digianantonio
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Joshua Temple
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Constanze Schneider
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | - Hanna-Mari Baldauf
- Max von Pettenkofer Institute & Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, LMU München, Munich, Germany
| | | | - Florian Rothweiler
- Institute for Medical Virology, Goethe-University, Frankfurt am Main, Germany
| | - Berna Bilen
- Faculty of Biological Sciences, Goethe-University, Frankfurt am Main, Germany
| | - Samira Farmand
- Faculty of Biological Sciences, Goethe-University, Frankfurt am Main, Germany
| | - Denisa Bojkova
- Institute for Medical Virology, Goethe-University, Frankfurt am Main, Germany
| | - Rui Costa
- Institute for Medical Virology, Goethe-University, Frankfurt am Main, Germany
| | - Nerea Ferreirós
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University of Frankfurt, Frankfurt, Germany
| | - Gerd Geisslinger
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University of Frankfurt, Frankfurt, Germany
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Project group Translational Medicine and Pharmacology (TMP), Frankfurt am Main, Germany
| | - Thomas Oellerich
- Department of Hematology/Oncology, Goethe-University, Frankfurt am Main, Germany
- Molecular Diagnostics Unit, Frankfurt Cancer Institute, Frankfurt am Main, Germany
- German Cancer Consortium/German Cancer Research Center, Heidelberg, Germany
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Oliver T Keppler
- Max von Pettenkofer Institute & Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, LMU München, Munich, Germany
- German Center for Infection Research (DZIF), Partner Site Munich, Munich, Germany
| | - Mark N Wass
- School of Biosciences, University of Kent, Canterbury, UK
| | | | - Jindrich Cinatl
- Institute for Medical Virology, Goethe-University, Frankfurt am Main, Germany.
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8
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Morris ER, Kunzelmann S, Caswell SJ, Purkiss AG, Kelly G, Taylor IA. Probing the Catalytic Mechanism and Inhibition of SAMHD1 Using the Differential Properties of R p- and S p-dNTPαS Diastereomers. Biochemistry 2021; 60:1682-1698. [PMID: 33988981 PMCID: PMC8173608 DOI: 10.1021/acs.biochem.0c00944] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
SAMHD1 is a fundamental regulator of cellular dNTPs that catalyzes their hydrolysis into 2'-deoxynucleoside and triphosphate, restricting the replication of viruses, including HIV-1, in CD4+ myeloid lineage and resting T-cells. SAMHD1 mutations are associated with the autoimmune disease Aicardi-Goutières syndrome (AGS) and certain cancers. More recently, SAMHD1 has been linked to anticancer drug resistance and the suppression of the interferon response to cytosolic nucleic acids after DNA damage. Here, we probe dNTP hydrolysis and inhibition of SAMHD1 using the Rp and Sp diastereomers of dNTPαS nucleotides. Our biochemical and enzymological data show that the α-phosphorothioate substitution in Sp-dNTPαS but not Rp-dNTPαS diastereomers prevents Mg2+ ion coordination at both the allosteric and catalytic sites, rendering SAMHD1 unable to form stable, catalytically active homotetramers or hydrolyze substrate dNTPs at the catalytic site. Furthermore, we find that Sp-dNTPαS diastereomers competitively inhibit dNTP hydrolysis, while Rp-dNTPαS nucleotides stabilize tetramerization and are hydrolyzed with similar kinetic parameters to cognate dNTPs. For the first time, we present a cocrystal structure of SAMHD1 with a substrate, Rp-dGTPαS, in which an Fe-Mg-bridging water species is poised for nucleophilic attack on the Pα. We conclude that it is the incompatibility of Mg2+, a hard Lewis acid, and the α-phosphorothioate thiol, a soft Lewis base, that prevents the Sp-dNTPαS nucleotides coordinating in a catalytically productive conformation. On the basis of these data, we present a model for SAMHD1 stereospecific hydrolysis of Rp-dNTPαS nucleotides and for a mode of competitive inhibition by Sp-dNTPαS nucleotides that competes with formation of the enzyme-substrate complex.
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Affiliation(s)
- Elizabeth R Morris
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, U.K
| | - Simone Kunzelmann
- Structural Biology Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, U.K
| | - Sarah J Caswell
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, U.K
| | - Andrew G Purkiss
- Structural Biology Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, U.K
| | - Geoff Kelly
- The Medical Research Council Biomedical NMR Centre, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, U.K
| | - Ian A Taylor
- Macromolecular Structure Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, U.K
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9
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Dual roles of SAMHD1 in tumor development and chemoresistance to anticancer drugs. Oncol Lett 2021; 21:451. [PMID: 33907561 PMCID: PMC8063254 DOI: 10.3892/ol.2021.12712] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 03/10/2021] [Indexed: 11/05/2022] Open
Abstract
Human sterile alpha motif and HD-domain-containing protein 1 (SAMHD1) has been identified as a GTP or dGTP-dependent deoxynucleotide triphosphohydrolase (dNTPase) and acts as an antiviral factor against certain retroviruses and DNA viruses. Genetic mutation in SAMHD1 causes the inflammatory Aicardi-Goutières Syndrome and abnormal intracellular deoxyribonucleoside triphosphates (dNTPs) pool. At present, the role of SAMHD1 in numerous types of cancer, such as chronic lymphocytic leukemia, lung cancer and colorectal cancer, is highly studied. Furthermore, it has been found that methylation, acetylation and phosphorylation are involved in the regulation of SAMHD1 expression, and that genetic mutations can cause changes in its activities, including dNTPase activity, long interspersed element type 1 (LINE-1) suppression and DNA damage repair, which could lead to uncontrolled cell cycle progression and cancer development. In addition, SAMHD1 has been reported to have a negative regulatory role in the chemosensitivity to anticancer drugs through its dNTPase activity. The present review aimed to summarize the regulation of SAMHD1 expression in cancer and its function in tumor growth and chemotherapy sensitivity, and discussed controversial points and future directions.
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10
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Kaspar F, Giessmann RT, Westarp S, Hellendahl KF, Krausch N, Thiele I, Walczak MC, Neubauer P, Wagner A. Spectral Unmixing-Based Reaction Monitoring of Transformations between Nucleosides and Nucleobases. Chembiochem 2020; 21:2604-2610. [PMID: 32324971 PMCID: PMC7540295 DOI: 10.1002/cbic.202000204] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/21/2020] [Indexed: 11/10/2022]
Abstract
The increased interest in (enzymatic) transformations between nucleosides and nucleobases has demanded the development of efficient analytical tools. In this report, we present an update and extension of our recently described method for monitoring these reactions by spectral unmixing. The presented method uses differences in the UV absorption spectra of nucleosides and nucleobases after alkaline quenching to derive their ratio based on spectral shape by fitting normalized reference spectra. It is applicable to a broad compound spectrum comprising more than 35 examples, offers HPLC-like accuracy, ease of handling and significant reductions in both cost and data acquisition time compared to other methods. This contribution details the principle of monitoring reactions by spectral unmixing, gives recommendations regarding solutions to common problems and applications that necessitate special sample treatment. We provide software, workflows and reference spectra that facilitate the straightforward and versatile application of the method.
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Affiliation(s)
- Felix Kaspar
- Institute of Biotechnology, Chair of Bioprocess EngineeringTechnische Universität Berlin ACK 24Ackerstraße 7613355BerlinGermany
- BioNukleo GmbHAckerstraße 7613355BerlinGermany
| | - Robert T. Giessmann
- Institute of Biotechnology, Chair of Bioprocess EngineeringTechnische Universität Berlin ACK 24Ackerstraße 7613355BerlinGermany
| | - Sarah Westarp
- Institute of Biotechnology, Chair of Bioprocess EngineeringTechnische Universität Berlin ACK 24Ackerstraße 7613355BerlinGermany
- BioNukleo GmbHAckerstraße 7613355BerlinGermany
| | - Katja F. Hellendahl
- Institute of Biotechnology, Chair of Bioprocess EngineeringTechnische Universität Berlin ACK 24Ackerstraße 7613355BerlinGermany
| | - Niels Krausch
- Institute of Biotechnology, Chair of Bioprocess EngineeringTechnische Universität Berlin ACK 24Ackerstraße 7613355BerlinGermany
| | - Isabel Thiele
- Institute of Biotechnology, Chair of Bioprocess EngineeringTechnische Universität Berlin ACK 24Ackerstraße 7613355BerlinGermany
| | - Miriam C. Walczak
- Institute of Biotechnology, Chair of Bioprocess EngineeringTechnische Universität Berlin ACK 24Ackerstraße 7613355BerlinGermany
- BioNukleo GmbHAckerstraße 7613355BerlinGermany
| | - Peter Neubauer
- Institute of Biotechnology, Chair of Bioprocess EngineeringTechnische Universität Berlin ACK 24Ackerstraße 7613355BerlinGermany
| | - Anke Wagner
- Institute of Biotechnology, Chair of Bioprocess EngineeringTechnische Universität Berlin ACK 24Ackerstraße 7613355BerlinGermany
- BioNukleo GmbHAckerstraße 7613355BerlinGermany
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11
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Wang C, Zhang K, Meng L, Zhang X, Song Y, Zhang Y, Gai Y, Zhang Y, Yu B, Wu J, Wang S, Yu X. The C-terminal domain of feline and bovine SAMHD1 proteins has a crucial role in lentiviral restriction. J Biol Chem 2020; 295:4252-4264. [PMID: 32075911 PMCID: PMC7105322 DOI: 10.1074/jbc.ra120.012767] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/14/2020] [Indexed: 01/29/2023] Open
Abstract
SAM and HD domain-containing protein 1 (SAMHD1) is a host factor that restricts reverse transcription of lentiviruses such as HIV in myeloid cells and resting T cells through its dNTP triphosphohydrolase (dNTPase) activity. Lentiviruses counteract this restriction by expressing the accessory protein Vpx or Vpr, which targets SAMHD1 for proteasomal degradation. SAMHD1 is conserved among mammals, and the feline and bovine SAMHD1 proteins (fSAM and bSAM) restrict lentiviruses by reducing cellular dNTP concentrations. However, the functional regions of fSAM and bSAM that are required for their biological functions are not well-characterized. Here, to establish alternative models to investigate SAMHD1 in vivo, we studied the restriction profile of fSAM and bSAM against different primate lentiviruses. We found that both fSAM and bSAM strongly restrict primate lentiviruses and that Vpx induces the proteasomal degradation of both fSAM and bSAM. Further investigation identified one and five amino acid sites in the C-terminal domain (CTD) of fSAM and bSAM, respectively, that are required for Vpx-mediated degradation. We also found that the CTD of bSAM is directly involved in mediating bSAM's antiviral activity by regulating dNTPase activity, whereas the CTD of fSAM is not. Our results suggest that the CTDs of fSAM and bSAM have important roles in their antiviral functions. These findings advance our understanding of the mechanism of fSAM- and bSAM-mediated viral restriction and might inform strategies for improving HIV animal models.
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Affiliation(s)
- Chu Wang
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China; The First Hospital and Institute of Immunology, Jilin University, Changchun 130012, China
| | - Kaikai Zhang
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Lina Meng
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Xin Zhang
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Yanan Song
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Ying Zhang
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Yanxin Gai
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Yuepeng Zhang
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Bin Yu
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China; Key Laboratory for Molecular Enzymology and Engineering, the Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Jiaxin Wu
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China; Key Laboratory for Molecular Enzymology and Engineering, the Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China
| | - Song Wang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130012, China
| | - Xianghui Yu
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun 130012, China; Key Laboratory for Molecular Enzymology and Engineering, the Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China.
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12
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Rudd SG, Tsesmetzis N, Sanjiv K, Paulin CBJ, Sandhow L, Kutzner J, Hed Myrberg I, Bunten SS, Axelsson H, Zhang SM, Rasti A, Mäkelä P, Coggins SA, Tao S, Suman S, Branca RM, Mermelekas G, Wiita E, Lee S, Walfridsson J, Schinazi RF, Kim B, Lehtiö J, Rassidakis GZ, Pokrovskaja Tamm K, Warpman‐Berglund U, Heyman M, Grandér D, Lehmann S, Lundbäck T, Qian H, Henter J, Schaller T, Helleday T, Herold N. Ribonucleotide reductase inhibitors suppress SAMHD1 ara-CTPase activity enhancing cytarabine efficacy. EMBO Mol Med 2020; 12:e10419. [PMID: 31950591 PMCID: PMC7059017 DOI: 10.15252/emmm.201910419] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 12/15/2019] [Accepted: 12/17/2019] [Indexed: 01/23/2023] Open
Abstract
The deoxycytidine analogue cytarabine (ara-C) remains the backbone treatment of acute myeloid leukaemia (AML) as well as other haematological and lymphoid malignancies, but must be combined with other chemotherapeutics to achieve cure. Yet, the underlying mechanism dictating synergistic efficacy of combination chemotherapy remains largely unknown. The dNTPase SAMHD1, which regulates dNTP homoeostasis antagonistically to ribonucleotide reductase (RNR), limits ara-C efficacy by hydrolysing the active triphosphate metabolite ara-CTP. Here, we report that clinically used inhibitors of RNR, such as gemcitabine and hydroxyurea, overcome the SAMHD1-mediated barrier to ara-C efficacy in primary blasts and mouse models of AML, displaying SAMHD1-dependent synergy with ara-C. We present evidence that this is mediated by dNTP pool imbalances leading to allosteric reduction of SAMHD1 ara-CTPase activity. Thus, SAMHD1 constitutes a novel biomarker for combination therapies of ara-C and RNR inhibitors with immediate consequences for clinical practice to improve treatment of AML.
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13
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Zhang Z, Zheng L, Yu Y, Wu J, Yang F, Xu Y, Guo Q, Wu X, Cao S, Cao L, Song X. Involvement of SAMHD1 in dNTP homeostasis and the maintenance of genomic integrity and oncotherapy (Review). Int J Oncol 2020; 56:879-888. [PMID: 32319570 DOI: 10.3892/ijo.2020.4988] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 02/07/2020] [Indexed: 11/06/2022] Open
Abstract
Sterile alpha motif and histidine/aspartic acid domain‑containing protein 1 (SAMHD1), the only deoxynucleotide triphosphate (dNTP) hydrolase in eukaryotes, plays a crucial role in regulating the dynamic balance and ratio of cellular dNTP pools. Furthermore, SAMHD1 has been reported to be involved in the pathological process of several diseases. Homozygous SAMHD1 mutations have been identified in immune system disorders, such as autoimmune disease Aicardi‑Goutières syndrome (AGS), whose primary pathogenesis is associated with the abnormal accumulation and disproportion of dNTPs. SAMHD1 is also considered to be an intrinsic virus‑restriction factor by suppressing the viral infection process, including reverse transcription, replication, packaging and transmission. In addition, SAMHD1 has been shown to promote genome integrity during homologous recombination following DNA damage, thus being considered a promising candidate for oncotherapy applications. The present review summarizes the molecular mechanisms of SAMHD1 regarding the regulation of dNTP homeostasis and DNA damage response. Additionally, its potential effects on tumorigenesis and oncotherapy are reported.
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Affiliation(s)
- Zhou Zhang
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Lixia Zheng
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Yang Yu
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Jinying Wu
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Fan Yang
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Yingxi Xu
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Qiqiang Guo
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Xuan Wu
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Sunrun Cao
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Liu Cao
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Xiaoyu Song
- College of Basic Medical Science, Institute of Translational Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
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14
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Jiang H, Xue X, Panda S, Kawale A, Hooy RM, Liang F, Sohn J, Sung P, Gekara NO. Chromatin-bound cGAS is an inhibitor of DNA repair and hence accelerates genome destabilization and cell death. EMBO J 2019; 38:e102718. [PMID: 31544964 PMCID: PMC6826206 DOI: 10.15252/embj.2019102718] [Citation(s) in RCA: 165] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/19/2019] [Accepted: 09/02/2019] [Indexed: 12/19/2022] Open
Abstract
DNA repair via homologous recombination (HR) is indispensable for genome integrity and cell survival but if unrestrained can result in undesired chromosomal rearrangements. The regulatory mechanisms of HR are not fully understood. Cyclic GMP-AMP synthase (cGAS) is best known as a cytosolic innate immune sensor critical for the outcome of infections, inflammatory diseases, and cancer. Here, we report that cGAS is primarily a chromatin-bound protein that inhibits DNA repair by HR, thereby accelerating genome destabilization, micronucleus generation, and cell death under conditions of genomic stress. This function is independent of the canonical STING-dependent innate immune activation and is physiologically relevant for irradiation-induced depletion of bone marrow cells in mice. Mechanistically, we demonstrate that inhibition of HR repair by cGAS is linked to its ability to self-oligomerize, causing compaction of bound template dsDNA into a higher-ordered state less amenable to strand invasion by RAD51-coated ssDNA filaments. This previously unknown role of cGAS has implications for understanding its involvement in genome instability-associated disorders including cancer.
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Affiliation(s)
- Hui Jiang
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Xiaoyu Xue
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA.,Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX, USA
| | - Swarupa Panda
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Ajinkya Kawale
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Richard M Hooy
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Fengshan Liang
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Jungsan Sohn
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA.,Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Nelson O Gekara
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden.,Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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15
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Oellerich T, Schneider C, Thomas D, Knecht KM, Buzovetsky O, Kaderali L, Schliemann C, Bohnenberger H, Angenendt L, Hartmann W, Wardelmann E, Rothenburger T, Mohr S, Scheich S, Comoglio F, Wilke A, Ströbel P, Serve H, Michaelis M, Ferreirós N, Geisslinger G, Xiong Y, Keppler OT, Cinatl J. Selective inactivation of hypomethylating agents by SAMHD1 provides a rationale for therapeutic stratification in AML. Nat Commun 2019; 10:3475. [PMID: 31375673 PMCID: PMC6677770 DOI: 10.1038/s41467-019-11413-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 07/08/2019] [Indexed: 02/08/2023] Open
Abstract
Hypomethylating agents decitabine and azacytidine are regarded as interchangeable in the treatment of acute myeloid leukemia (AML). However, their mechanisms of action remain incompletely understood, and predictive biomarkers for HMA efficacy are lacking. Here, we show that the bioactive metabolite decitabine triphosphate, but not azacytidine triphosphate, functions as activator and substrate of the triphosphohydrolase SAMHD1 and is subject to SAMHD1-mediated inactivation. Retrospective immunohistochemical analysis of bone marrow specimens from AML patients at diagnosis revealed that SAMHD1 expression in leukemic cells inversely correlates with clinical response to decitabine, but not to azacytidine. SAMHD1 ablation increases the antileukemic activity of decitabine in AML cell lines, primary leukemic blasts, and xenograft models. AML cells acquire resistance to decitabine partly by SAMHD1 up-regulation. Together, our data suggest that SAMHD1 is a biomarker for the stratified use of hypomethylating agents in AML patients and a potential target for the treatment of decitabine-resistant leukemia. In acute myeloid leukemia, hypomethylating agents decitabine and azacytidine are used interchangeably. Here, the authors show that the major metabolite of decitabine, but not azacytidine, is subject to SAMHD1 inactivation, highlighting SAMHD1 as a potential biomarker and therapeutic target
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Affiliation(s)
- Thomas Oellerich
- Department of Medicine II, Hematology/Oncology, Goethe University of Frankfurt, Frankfurt, 60590, Germany.,German Cancer Consortium/German Cancer Research Center, Heidelberg, 69120, Germany.,Frankfurt Cancer Institute, Goethe University Frankfurt, Frankfurt, 60596, Germany
| | - Constanze Schneider
- Department of Medicine II, Hematology/Oncology, Goethe University of Frankfurt, Frankfurt, 60590, Germany.,Frankfurt Cancer Institute, Goethe University Frankfurt, Frankfurt, 60596, Germany.,Institute of Medical Virology, University of Frankfurt, Frankfurt, 60590, Germany
| | - Dominique Thomas
- pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University of Frankfurt, Frankfurt, 60590, Germany
| | - Kirsten M Knecht
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Olga Buzovetsky
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Lars Kaderali
- Institute of Bioinformatics, University Medicine Greifswald, Greifswald, 17475, Germany
| | | | | | - Linus Angenendt
- Department of Medicine A, University Hospital Münster, Münster, 48149, Germany
| | - Wolfgang Hartmann
- Gerhard Domagk Institute for Pathology, University Hospital Münster, Münster, 48149, Germany
| | - Eva Wardelmann
- Gerhard Domagk Institute for Pathology, University Hospital Münster, Münster, 48149, Germany
| | - Tamara Rothenburger
- Institute of Medical Virology, University of Frankfurt, Frankfurt, 60590, Germany
| | - Sebastian Mohr
- Department of Medicine II, Hematology/Oncology, Goethe University of Frankfurt, Frankfurt, 60590, Germany
| | - Sebastian Scheich
- Department of Medicine II, Hematology/Oncology, Goethe University of Frankfurt, Frankfurt, 60590, Germany
| | - Federico Comoglio
- Department of Haematology, Cambridge Institute of Medical Research, Cambridge University, Cambridge, CB2 0XY, UK
| | - Anne Wilke
- Department of Medicine II, Hematology/Oncology, Goethe University of Frankfurt, Frankfurt, 60590, Germany
| | - Philipp Ströbel
- Institute of Pathology, University Medical Center, Göttingen, 37075, Germany
| | - Hubert Serve
- Department of Medicine II, Hematology/Oncology, Goethe University of Frankfurt, Frankfurt, 60590, Germany.,German Cancer Consortium/German Cancer Research Center, Heidelberg, 69120, Germany.,Frankfurt Cancer Institute, Goethe University Frankfurt, Frankfurt, 60596, Germany
| | - Martin Michaelis
- Industrial Biotechnology Centre and School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Nerea Ferreirós
- pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University of Frankfurt, Frankfurt, 60590, Germany
| | - Gerd Geisslinger
- pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe University of Frankfurt, Frankfurt, 60590, Germany.,Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Project group Translational Medicine and Pharmacology (TMP), Frankfurt, 60596, Germany
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Oliver T Keppler
- Institute of Medical Virology, University of Frankfurt, Frankfurt, 60590, Germany. .,Max von Pettenkofer Institute, Virology, Faculty of Medicine, LMU München, Munich, 80336, Germany.
| | - Jindrich Cinatl
- Institute of Medical Virology, University of Frankfurt, Frankfurt, 60590, Germany.
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16
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Kaspar F, Giessmann RT, Krausch N, Neubauer P, Wagner A, Gimpel M. A UV/Vis Spectroscopy-Based Assay for Monitoring of Transformations Between Nucleosides and Nucleobases. Methods Protoc 2019; 2:E60. [PMID: 31311105 PMCID: PMC6789650 DOI: 10.3390/mps2030060] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/10/2019] [Accepted: 07/10/2019] [Indexed: 12/25/2022] Open
Abstract
Efficient reaction monitoring is crucial for data acquisition in kinetic and mechanistic studies. However, for conversions of nucleosides to their corresponding nucleobases, as observed in enzymatically catalyzed nucleoside phosphorylation reactions, the current analytical arsenal does not meet modern requirements regarding cost, speed of analysis and high throughput. Herein, we present a UV/Vis spectroscopy-based assay employing an algorithm for spectral unmixing in a 96-well plate format. The algorithm relies on fitting of reference spectra of nucleosides and their bases to experimental spectra and allows determination of nucleoside/nucleobase ratios in solution with high precision. The experimental procedure includes appropriate dilution of a sample into aqueous alkaline solution, transfer to a multi-well plate, measurement of a UV/Vis spectrum and subsequent in silico spectral unmixing. This enables data collection in a high-throughput fashion and reduces costs compared to state-of-the-art HPLC analyses by approximately 5-fold while being 20-fold faster and offering comparable precision. Additionally, the method is robust regarding dilution and sample transfer errors as it only considers spectral form and not absolute intensity. It can be applied to all natural nucleosides and nucleobases and even unnatural ones as demonstrated by several examples.
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Affiliation(s)
- Felix Kaspar
- Bioprocess Engineering, Department of Biotechnology, Technische Universität Berlin, Ackerstraße 76, ACK24, D-13355 Berlin, Germany
| | - Robert T Giessmann
- Bioprocess Engineering, Department of Biotechnology, Technische Universität Berlin, Ackerstraße 76, ACK24, D-13355 Berlin, Germany
| | - Niels Krausch
- Bioprocess Engineering, Department of Biotechnology, Technische Universität Berlin, Ackerstraße 76, ACK24, D-13355 Berlin, Germany
| | - Peter Neubauer
- Bioprocess Engineering, Department of Biotechnology, Technische Universität Berlin, Ackerstraße 76, ACK24, D-13355 Berlin, Germany
| | - Anke Wagner
- Bioprocess Engineering, Department of Biotechnology, Technische Universität Berlin, Ackerstraße 76, ACK24, D-13355 Berlin, Germany.
- BioNukleo GmbH, Ackerstraße 76, D-13355 Berlin, Germany.
| | - Matthias Gimpel
- Bioprocess Engineering, Department of Biotechnology, Technische Universität Berlin, Ackerstraße 76, ACK24, D-13355 Berlin, Germany
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17
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Abstract
Cyclic GMP-AMP synthase, cGAS, converts ATP and GTP into a cyclic dinucleotide second messenger, cyclic GMP-AMP or cGAMP, through its enzymatic, nucleotidyl transferase (NTase) activity. Although many methods are available to directly measure cGAMP production, these assays often have high cost of implementation and/or experimental limitations. This chapter details how to implement an alternative approach that is relatively inexpensive, accurate and medium-throughput. The assay measures cGAS NTase activity by quantifying pyrophosphate production, a byproduct of the cGAS reaction. A coupling enzyme, pyrophosphatase, catalyzes the hydrolysis of pyrophosphate into inorganic phosphate, which enables facile detection of cGAS activity through conventional phosphomolybdate-malachite green absorbance methodology. This method is amenable for conventional steady-state kinetic measurements as well as high-throughput compound screening.
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Affiliation(s)
- Richard Hooy
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
| | - Jungsan Sohn
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
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18
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Mauney CH, Perrino FW, Hollis T. Identification of Inhibitors of the dNTP Triphosphohydrolase SAMHD1 Using a Novel and Direct High-Throughput Assay. Biochemistry 2018; 57:6624-6636. [PMID: 30380297 DOI: 10.1021/acs.biochem.8b01038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dNTP triphosphohydrolase SAMHD1 is a regulator of cellular dNTP pools. Given its central role in nucleotide metabolism, SAMHD1 performs important functions in cellular homeostasis, cell cycle regulation, and innate immunity. It therefore represents a high-profile target for small molecule drug design. SAMHD1 has a complex mechanism of catalytic activation that makes the design of an activating compound challenging. However, an inhibitor of SAMHD1 could serve multiple therapeutic roles, including the potentiation of antiviral and anticancer drug regimens. The lack of high-throughput screens that directly measure SAMHD1 catalytic activity has impeded efforts to identify inhibitors of SAMHD1. Here we describe a novel high-throughput screen that directly measures SAMHD1 catalytic activity. This assay results in a colorimetric end point that can be read spectrophotometrically and utilizes bis(4-nitrophenyl) phosphate as the substrate and Mn2+ as the activating cation that facilitates catalysis. When used to screen a library of Food and Drug Administration-approved drugs, this HTS identified multiple novel compounds that inhibited SAMHD1 dNTPase activity at micromolar concentrations.
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Affiliation(s)
- Christopher H Mauney
- Center for Structural Biology, Department of Biochemistry , Wake Forest School of Medicine , Winston-Salem , North Carolina 27157 , United States
| | - Fred W Perrino
- Center for Structural Biology, Department of Biochemistry , Wake Forest School of Medicine , Winston-Salem , North Carolina 27157 , United States
| | - Thomas Hollis
- Center for Structural Biology, Department of Biochemistry , Wake Forest School of Medicine , Winston-Salem , North Carolina 27157 , United States
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19
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Chen S, Bonifati S, Qin Z, St Gelais C, Wu L. SAMHD1 Suppression of Antiviral Immune Responses. Trends Microbiol 2018; 27:254-267. [PMID: 30336972 DOI: 10.1016/j.tim.2018.09.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/17/2018] [Accepted: 09/26/2018] [Indexed: 12/18/2022]
Abstract
SAMHD1 is a host triphosphohydrolase that degrades intracellular deoxynucleoside triphosphates (dNTPs) to a lower level that restricts viral DNA synthesis, and thus prevents replication of diverse viruses in nondividing cells. Recent progress indicates that SAMHD1 negatively regulates antiviral innate immune responses and inflammation through interacting with various key proteins in immune signaling and DNA damage-repair pathways. SAMHD1 can also modulate antibody production in adaptive immune responses. In this review, we summarize how SAMHD1 regulates antiviral immune responses through distinct mechanisms, and discuss the implications of these new functions of SAMHD1. Furthermore, we propose important new questions and future directions that can advance functional and mechanistic studies of SAMHD1-mediated immune regulation during viral infections.
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Affiliation(s)
- Shuliang Chen
- School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, PR China; Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Serena Bonifati
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Zhihua Qin
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Corine St Gelais
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Li Wu
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA.
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20
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The structural basis for cancer drug interactions with the catalytic and allosteric sites of SAMHD1. Proc Natl Acad Sci U S A 2018; 115:E10022-E10031. [PMID: 30305425 DOI: 10.1073/pnas.1805593115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
SAMHD1 is a deoxynucleoside triphosphate triphosphohydrolase (dNTPase) that depletes cellular dNTPs in noncycling cells to promote genome stability and to inhibit retroviral and herpes viral replication. In addition to being substrates, cellular nucleotides also allosterically regulate SAMHD1 activity. Recently, it was shown that high expression levels of SAMHD1 are also correlated with significantly worse patient responses to nucleotide analog drugs important for treating a variety of cancers, including acute myeloid leukemia (AML). In this study, we used biochemical, structural, and cellular methods to examine the interactions of various cancer drugs with SAMHD1. We found that both the catalytic and the allosteric sites of SAMHD1 are sensitive to sugar modifications of the nucleotide analogs, with the allosteric site being significantly more restrictive. We crystallized cladribine-TP, clofarabine-TP, fludarabine-TP, vidarabine-TP, cytarabine-TP, and gemcitabine-TP in the catalytic pocket of SAMHD1. We found that all of these drugs are substrates of SAMHD1 and that the efficacy of most of these drugs is affected by SAMHD1 activity. Of the nucleotide analogs tested, only cladribine-TP with a deoxyribose sugar efficiently induced the catalytically active SAMHD1 tetramer. Together, these results establish a detailed framework for understanding the substrate specificity and allosteric activation of SAMHD1 with regard to nucleotide analogs, which can be used to improve current cancer and antiviral therapies.
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21
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Hooy RM, Sohn J. The allosteric activation of cGAS underpins its dynamic signaling landscape. eLife 2018; 7:39984. [PMID: 30295605 PMCID: PMC6211831 DOI: 10.7554/elife.39984] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 10/05/2018] [Indexed: 12/22/2022] Open
Abstract
Cyclic G/AMP synthase (cGAS) initiates type-1 interferon responses against cytosolic double-stranded (ds)DNA, which range from antiviral gene expression to apoptosis. The mechanism by which cGAS shapes this diverse signaling landscape remains poorly defined. We find that substrate-binding and dsDNA length-dependent binding are coupled to the intrinsic dimerization equilibrium of cGAS, with its N-terminal domain potentiating dimerization. Notably, increasing the dimeric fraction by raising cGAS and substrate concentrations diminishes duplex length-dependent activation, but does not negate the requirement for dsDNA. These results demonstrate that reaction context dictates the duplex length dependence, reconciling competing claims on the role of dsDNA length in cGAS activation. Overall, our study reveals how ligand-mediated allostery positions cGAS in standby, ready to tune its signaling pathway in a switch-like fashion. The human immune system protects the body from various threats such as damaged cells or invading microbes. Many of these threats can move molecules of DNA, which are usually only found within a central compartment in the cell known as the nucleus, to the surrounding area, the cytoplasm. An enzyme called cGAS searches for DNA in the cytoplasm of human cells. When DNA binds to cGAS it activates the enzyme to convert certain molecules (referred to as ‘substrates’) into another molecule (the ‘signal’) that triggers various immune responses to protect the body against the threat. To produce the signal, two cGAS enzymes need to work together as a single unit called a dimer. The length of DNA molecules in the cytoplasm of cells can vary widely. It was initially thought that DNA molecules of any length binding to cGAS could activate the enzyme to a similar degree, but later studies demonstrated that this is not the case. However, it remains unclear how the length of the DNA could affect the activity of the enzyme, or why some of the earlier studies reported different findings. Hooy and Sohn used biochemical approaches to study the human cGAS enzyme. The experiments show that cGAS can form dimers even when no DNA is present. However, when DNA bound to cGAS, the enzyme was more likely to form dimers. Longer DNA molecules were better at promoting cGAS dimers to form than shorter DNA molecules. The binding of substrates to cGAS also made it more likely that the enzyme would form dimers. These findings suggest that inside cells cGAS is primed to trigger a switch-like response when it detects DNA in the cytoplasm. The work of Hooy and Sohn establishes a simple set of rules to predict how cGAS might respond in a given situation. Such information may aid in designing and tailoring efforts to regulate immune responses in human patients, and may provide insight into why the body responds to biological threats in different ways.
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Affiliation(s)
- Richard M Hooy
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Jungsan Sohn
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, United States
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22
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Tsesmetzis N, Paulin CBJ, Rudd SG, Herold N. Nucleobase and Nucleoside Analogues: Resistance and Re-Sensitisation at the Level of Pharmacokinetics, Pharmacodynamics and Metabolism. Cancers (Basel) 2018; 10:cancers10070240. [PMID: 30041457 PMCID: PMC6071274 DOI: 10.3390/cancers10070240] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 07/18/2018] [Accepted: 07/20/2018] [Indexed: 02/07/2023] Open
Abstract
Antimetabolites, in particular nucleobase and nucleoside analogues, are cytotoxic drugs that, starting from the small field of paediatric oncology, in combination with other chemotherapeutics, have revolutionised clinical oncology and transformed cancer into a curable disease. However, even though combination chemotherapy, together with radiation, surgery and immunotherapy, can nowadays cure almost all types of cancer, we still fail to achieve this for a substantial proportion of patients. The understanding of differences in metabolism, pharmacokinetics, pharmacodynamics, and tumour biology between patients that can be cured and patients that cannot, builds the scientific basis for rational therapy improvements. Here, we summarise current knowledge of how tumour-specific and patient-specific factors can dictate resistance to nucleobase/nucleoside analogues, and which strategies of re-sensitisation exist. We revisit well-established hurdles to treatment efficacy, like the blood-brain barrier and reduced deoxycytidine kinase activity, but will also discuss the role of novel resistance factors, such as SAMHD1. A comprehensive appreciation of the complex mechanisms that underpin the failure of chemotherapy will hopefully inform future strategies of personalised medicine.
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Affiliation(s)
- Nikolaos Tsesmetzis
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, 171 77 Stockholm, Sweden.
| | - Cynthia B J Paulin
- Science for Life Laboratory, Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden.
| | - Sean G Rudd
- Science for Life Laboratory, Department of Oncology-Pathology, Karolinska Institutet, 171 65 Stockholm, Sweden.
| | - Nikolas Herold
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, 171 77 Stockholm, Sweden.
- Paediatric Oncology, Theme of Children's and Women's Health, Karolinska University Hospital Solna, 171 76 Stockholm, Sweden.
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23
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Mauney CH, Hollis T. SAMHD1: Recurring roles in cell cycle, viral restriction, cancer, and innate immunity. Autoimmunity 2018; 51:96-110. [PMID: 29583030 PMCID: PMC6117824 DOI: 10.1080/08916934.2018.1454912] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 03/16/2018] [Indexed: 12/24/2022]
Abstract
Sterile alpha motif and histidine-aspartic acid domain-containing protein 1 (SAMHD1) is a deoxynucleotide triphosphate (dNTP) hydrolase that plays an important role in the homeostatic balance of cellular dNTPs. Its emerging role as an effector of innate immunity is affirmed by mutations in the SAMHD1 gene that cause the severe autoimmune disease, Aicardi-Goutieres syndrome (AGS) and that are linked to cancer. Additionally, SAMHD1 functions as a restriction factor for retroviruses, such as HIV. Here, we review the current biochemical and biological properties of the enzyme including its structure, activity, and regulation by post-translational modifications in the context of its cellular function. We outline open questions regarding the biology of SAMHD1 whose answers will be important for understanding its function as a regulator of cell cycle progression, genomic integrity, and in autoimmunity.
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Affiliation(s)
- Christopher H Mauney
- a Department of Biochemistry , Center for Structural Biology, Wake Forest School of Medicine , Winston Salem , NC , USA
| | - Thomas Hollis
- a Department of Biochemistry , Center for Structural Biology, Wake Forest School of Medicine , Winston Salem , NC , USA
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24
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A Cyclin-Binding Motif in Human SAMHD1 Is Required for Its HIV-1 Restriction, dNTPase Activity, Tetramer Formation, and Efficient Phosphorylation. J Virol 2018; 92:JVI.01787-17. [PMID: 29321329 DOI: 10.1128/jvi.01787-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/22/2017] [Indexed: 12/22/2022] Open
Abstract
Sterile alpha motif and HD domain-containing protein 1 (SAMHD1) regulates intracellular deoxynucleoside triphosphate (dNTP) levels and functions as a retroviral restriction factor through its dNTP triphosphohydrolase (dNTPase) activity. Human SAMHD1 interacts with cell cycle regulatory proteins cyclin A2, cyclin-dependent kinase 1 (CDK1), and CDK2. This interaction mediates phosphorylation of SAMHD1 at threonine 592 (T592), which negatively regulates HIV-1 restriction. We previously reported that the interaction is mediated, at least in part, through a cyclin-binding motif (RXL, amino acids [aa] 451 to 453). To understand the role of the RXL motif in regulating SAMHD1 activity, we performed structural and functional analyses of RXL mutants and the effect on HIV-1 restriction. We found that the RXL mutation (R451A and L453A, termed RL/AA) disrupted SAMHD1 tetramer formation and abolished its dNTPase activity in vitro and in cells. Compared to wild-type (WT) SAMHD1, the RL/AA mutant failed to restrict HIV-1 infection and had reduced binding to cyclin A2. WT SAMHD1 and RL/AA mutant proteins were degraded by Vpx from HIV-2 but were not spontaneously ubiquitinated in the absence of Vpx. Analysis of proteasomal and autophagy degradation revealed that WT and RL/AA SAMHD1 protein levels were enhanced only when both pathways of degradation were simultaneously inhibited. Our results demonstrate that the RXL motif of human SAMHD1 is required for its HIV-1 restriction, tetramer formation, dNTPase activity, and efficient phosphorylation at T592. These findings identify a new functional domain of SAMHD1 important for its structural integrity, enzyme activity, phosphorylation, and HIV-1 restriction.IMPORTANCE SAMHD1 is the first mammalian dNTPase identified as a restriction factor that inhibits HIV-1 replication by decreasing the intracellular dNTP pool in nondividing cells, although the critical mechanisms regulating SAMHD1 function remain unclear. We previously reported that mutations of a cyclin-binding RXL motif in human SAMHD1 significantly affect protein expression levels, half-life, nuclear localization, and phosphorylation, suggesting an important role of this motif in modulating SAMHD1 functions in cells. To further understand the significance and mechanisms of the RXL motif in regulating SAMHD1 activity, we performed structural and functional analyses of the RXL motif mutation and its effect on HIV-1 restriction. Our results indicate that the RXL motif is critical for tetramer formation, dNTPase activity, and HIV-1 restriction. These findings help us understand SAMHD1 interactions with other host proteins and the mechanisms regulating SAMHD1 structure and functions in cells.
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25
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Buzovetsky O, Tang C, Knecht KM, Antonucci JM, Wu L, Ji X, Xiong Y. The SAM domain of mouse SAMHD1 is critical for its activation and regulation. Nat Commun 2018; 9:411. [PMID: 29379009 PMCID: PMC5788916 DOI: 10.1038/s41467-017-02783-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/28/2017] [Indexed: 11/09/2022] Open
Abstract
Human SAMHD1 (hSAMHD1) is a retroviral restriction factor that blocks HIV-1 infection by depleting the cellular nucleotides required for viral reverse transcription. SAMHD1 is allosterically activated by nucleotides that induce assembly of the active tetramer. Although the catalytic core of hSAMHD1 has been studied extensively, previous structures have not captured the regulatory SAM domain. Here we report the crystal structure of full-length SAMHD1 by capturing mouse SAMHD1 (mSAMHD1) structures in three different nucleotide bound states. Although mSAMHD1 and hSAMHD1 are highly similar in sequence and function, we find that mSAMHD1 possesses a more complex nucleotide-induced activation process, highlighting the regulatory role of the SAM domain. Our results provide insights into the regulation of SAMHD1 activity, thereby facilitating the improvement of HIV mouse models and the development of new therapies for certain cancers and autoimmune diseases.
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Affiliation(s)
- Olga Buzovetsky
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Chenxiang Tang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Kirsten M Knecht
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Jenna M Antonucci
- Center of Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, 43210, USA
| | - Li Wu
- Center of Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, 43210, USA
| | - Xiaoyun Ji
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, 210023, China.
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA.
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26
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Herold N, Rudd SG, Sanjiv K, Kutzner J, Bladh J, Paulin CBJ, Helleday T, Henter JI, Schaller T. SAMHD1 protects cancer cells from various nucleoside-based antimetabolites. Cell Cycle 2017; 16:1029-1038. [PMID: 28436707 PMCID: PMC5499833 DOI: 10.1080/15384101.2017.1314407] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Recently, we demonstrated that sterile α motif and HD domain containing protein 1 (SAMHD1) is a major barrier in acute myelogenous leukemia (AML) cells to the cytotoxicity of cytarabine (ara-C), the most important drug in AML treatment. Ara-C is intracellularly converted by the canonical dNTP synthesis pathway to ara-CTP, which serves as a substrate but not an allosteric activator of SAMHD1. Using an AML mouse model, we show here that wild type but not catalytically inactive SAMHD1 reduces ara-C treatment efficacy in vivo. Expanding the clinically relevant substrates of SAMHD1, we demonstrate that THP-1 CRISPR/Cas9 cells lacking a functional SAMHD1 gene showed increased sensitivity to the antimetabolites nelarabine, fludarabine, decitabine, vidarabine, clofarabine, and trifluridine. Within this Extra View, we discuss and build upon both these and our previously reported findings, and propose SAMHD1 is likely active against a variety of nucleoside analog antimetabolites present in anti-cancer chemotherapies. Thus, SAMHD1 may constitute a promising target to improve a wide range of therapies for both hematological and non-haematological malignancies.
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Affiliation(s)
- Nikolas Herold
- a Childhood Cancer Research Unit, Department of Women's and Children's Health , Karolinska Institutet , Stockholm , Sweden.,b Theme of Children's and Women's Health , Astrid Lindgren Children's Hospital, Karolinska University Hospital , Stockholm , Sweden
| | - Sean G Rudd
- c Science for Life Laboratory, Division of Translational Medicine and Chemical Biology , Department of Medical Biochemistry and Biophysics , Karolinska Institutet , Stockholm , Sweden
| | - Kumar Sanjiv
- c Science for Life Laboratory, Division of Translational Medicine and Chemical Biology , Department of Medical Biochemistry and Biophysics , Karolinska Institutet , Stockholm , Sweden
| | - Juliane Kutzner
- d Department of Infectious Diseases, Virology , University Hospital Heidelberg , Heidelberg , Germany
| | - Julia Bladh
- a Childhood Cancer Research Unit, Department of Women's and Children's Health , Karolinska Institutet , Stockholm , Sweden
| | - Cynthia B J Paulin
- c Science for Life Laboratory, Division of Translational Medicine and Chemical Biology , Department of Medical Biochemistry and Biophysics , Karolinska Institutet , Stockholm , Sweden
| | - Thomas Helleday
- c Science for Life Laboratory, Division of Translational Medicine and Chemical Biology , Department of Medical Biochemistry and Biophysics , Karolinska Institutet , Stockholm , Sweden
| | - Jan-Inge Henter
- a Childhood Cancer Research Unit, Department of Women's and Children's Health , Karolinska Institutet , Stockholm , Sweden.,b Theme of Children's and Women's Health , Astrid Lindgren Children's Hospital, Karolinska University Hospital , Stockholm , Sweden
| | - Torsten Schaller
- d Department of Infectious Diseases, Virology , University Hospital Heidelberg , Heidelberg , Germany
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27
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Herold N, Rudd SG, Ljungblad L, Sanjiv K, Myrberg IH, Paulin CBJ, Heshmati Y, Hagenkort A, Kutzner J, Page BDG, Calderón-Montaño JM, Loseva O, Jemth AS, Bulli L, Axelsson H, Tesi B, Valerie NCK, Höglund A, Bladh J, Wiita E, Sundin M, Uhlin M, Rassidakis G, Heyman M, Tamm KP, Warpman-Berglund U, Walfridsson J, Lehmann S, Grandér D, Lundbäck T, Kogner P, Henter JI, Helleday T, Schaller T. Targeting SAMHD1 with the Vpx protein to improve cytarabine therapy for hematological malignancies. Nat Med 2017; 23:256-263. [PMID: 28067901 DOI: 10.1038/nm.4265] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/12/2016] [Indexed: 02/03/2023]
Abstract
The cytostatic deoxycytidine analog cytarabine (ara-C) is the most active agent available against acute myelogenous leukemia (AML). Together with anthracyclines, ara-C forms the backbone of AML treatment for children and adults. In AML, both the cytotoxicity of ara-C in vitro and the clinical response to ara-C therapy are correlated with the ability of AML blasts to accumulate the active metabolite ara-C triphosphate (ara-CTP), which causes DNA damage through perturbation of DNA synthesis. Differences in expression levels of known transporters or metabolic enzymes relevant to ara-C only partially account for patient-specific differential ara-CTP accumulation in AML blasts and response to ara-C treatment. Here we demonstrate that the deoxynucleoside triphosphate (dNTP) triphosphohydrolase SAM domain and HD domain 1 (SAMHD1) promotes the detoxification of intracellular ara-CTP pools. Recombinant SAMHD1 exhibited ara-CTPase activity in vitro, and cells in which SAMHD1 expression was transiently reduced by treatment with the simian immunodeficiency virus (SIV) protein Vpx were dramatically more sensitive to ara-C-induced cytotoxicity. CRISPR-Cas9-mediated disruption of the gene encoding SAMHD1 sensitized cells to ara-C, and this sensitivity could be abrogated by ectopic expression of wild-type (WT), but not dNTPase-deficient, SAMHD1. Mouse models of AML lacking SAMHD1 were hypersensitive to ara-C, and treatment ex vivo with Vpx sensitized primary patient-derived AML blasts to ara-C. Finally, we identified SAMHD1 as a risk factor in cohorts of both pediatric and adult patients with de novo AML who received ara-C treatment. Thus, SAMHD1 expression levels dictate patient sensitivity to ara-C, providing proof-of-concept that the targeting of SAMHD1 by Vpx could be an attractive therapeutic strategy for potentiating ara-C efficacy in hematological malignancies.
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Affiliation(s)
- Nikolas Herold
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden
| | - Sean G Rudd
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Linda Ljungblad
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden
| | - Kumar Sanjiv
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Ida Hed Myrberg
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden
| | - Cynthia B J Paulin
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Yaser Heshmati
- Department of Medicine, Center of Hematology and Regenerative Medicine, Karolinska Hospital and Karolinska Institutet, Stockholm, Sweden
| | - Anna Hagenkort
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Juliane Kutzner
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Brent D G Page
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - José M Calderón-Montaño
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Olga Loseva
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Ann-Sofie Jemth
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Lorenzo Bulli
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Hanna Axelsson
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Chemical Biology Consortium, Stockholm, Sweden
| | - Bianca Tesi
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden
| | - Nicholas C K Valerie
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Andreas Höglund
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Julia Bladh
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden
| | - Elisée Wiita
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Mikael Sundin
- Division of Pediatrics, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.,Paediatric Blood Disorders, Immunodeficiency and Stem Cell Transplantation, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Michael Uhlin
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Immunology and Transfusion Medicine, Karolinska University Hospital, Stockholm, Sweden
| | | | - Mats Heyman
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden
| | | | - Ulrika Warpman-Berglund
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Julian Walfridsson
- Department of Medicine, Center of Hematology and Regenerative Medicine, Karolinska Hospital and Karolinska Institutet, Stockholm, Sweden
| | - Sören Lehmann
- Department of Medicine, Center of Hematology and Regenerative Medicine, Karolinska Hospital and Karolinska Institutet, Stockholm, Sweden.,Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Dan Grandér
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Thomas Lundbäck
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Chemical Biology Consortium, Stockholm, Sweden
| | - Per Kogner
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden
| | - Jan-Inge Henter
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden
| | - Thomas Helleday
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Torsten Schaller
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
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28
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Bhattacharya A, Wang Z, White T, Buffone C, Nguyen LA, Shepard CN, Kim B, Demeler B, Diaz-Griffero F, Ivanov DN. Effects of T592 phosphomimetic mutations on tetramer stability and dNTPase activity of SAMHD1 can not explain the retroviral restriction defect. Sci Rep 2016; 6:31353. [PMID: 27511536 PMCID: PMC4980677 DOI: 10.1038/srep31353] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/18/2016] [Indexed: 12/30/2022] Open
Abstract
SAMHD1, a dNTP triphosphohydrolase, contributes to interferon signaling and restriction of retroviral replication. SAMHD1-mediated retroviral restriction is thought to result from the depletion of cellular dNTP pools, but it remains controversial whether the dNTPase activity of SAMHD1 is sufficient for restriction. The restriction ability of SAMHD1 is regulated in cells by phosphorylation on T592. Phosphomimetic mutations of T592 are not restriction competent, but appear intact in their ability to deplete cellular dNTPs. Here we use analytical ultracentrifugation, fluorescence polarization and NMR-based enzymatic assays to investigate the impact of phosphomimetic mutations on SAMHD1 tetramerization and dNTPase activity in vitro. We find that phosphomimetic mutations affect kinetics of tetramer assembly and disassembly, but their effects on tetramerization equilibrium and dNTPase activity are insignificant. In contrast, the Y146S/Y154S dimerization-defective mutant displays a severe dNTPase defect in vitro, but is indistinguishable from WT in its ability to deplete cellular dNTP pools and to restrict HIV replication. Our data suggest that the effect of T592 phosphorylation on SAMHD1 tetramerization is not likely to explain the retroviral restriction defect, and we hypothesize that enzymatic activity of SAMHD1 is subject to additional cellular regulatory mechanisms that have not yet been recapitulated in vitro.
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Affiliation(s)
- Akash Bhattacharya
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Zhonghua Wang
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Tommy White
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Cindy Buffone
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Laura A Nguyen
- Center for Drug Discovery, Department of Pediatrics, Emory School of Medicine, Atlanta, GA 30322, USA
| | - Caitlin N Shepard
- Center for Drug Discovery, Department of Pediatrics, Emory School of Medicine, Atlanta, GA 30322, USA
| | - Baek Kim
- Center for Drug Discovery, Department of Pediatrics, Emory School of Medicine, Atlanta, GA 30322, USA.,School of Pharmacy, Kyunghee University, Seoul, South Korea
| | - Borries Demeler
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Felipe Diaz-Griffero
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Dmitri N Ivanov
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229, USA
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29
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Singh D, Schaaper RM, Hochkoeppler A. A continuous spectrophotometric enzyme-coupled assay for deoxynucleoside triphosphate triphosphohydrolases. Anal Biochem 2015; 496:43-9. [PMID: 26723493 DOI: 10.1016/j.ab.2015.11.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 11/19/2015] [Accepted: 11/24/2015] [Indexed: 02/03/2023]
Abstract
We describe a continuous, spectrophotometric, enzyme-coupled assay useful to monitor reactions catalyzed by nucleoside triphosphohydrolases. In particular, using Escherichia coli deoxynucleoside triphosphohydrolase (Dgt), which hydrolyzes dGTP to deoxyguanosine and tripolyphosphate (PPPi) as the enzyme to be tested, we devised a procedure relying on purine nucleoside phosphorylase (PNPase) and xanthine oxidase (XOD) as the auxiliary enzymes. The deoxyguanosine released by Dgt can indeed be conveniently subjected to phosphorolysis by PNPase, yielding deoxyribose-1-phosphate and guanine, which in turn can be oxidized to 8-oxoguanine by XOD. By this means, it was possible to continuously detect Dgt activity at 297 nm, at which wavelength the difference between the molar extinction coefficients of 8-oxoguanine (8000 M(-1) cm(-1)) and guanine (1090 M(-1) cm(-1)) is maximal. The initial velocities of Dgt-catalyzed reactions were then determined in parallel with the enzyme-coupled assay and with a discontinuous high-performance liquid chromatography (HPLC) method able to selectively detect deoxyguanosine. Under appropriate conditions of excess auxiliary enzymes, the activities determined with our continuous enzyme-coupled assay were quantitatively comparable to those observed with the HPLC method. Moreover, the enzyme-coupled assay proved to be more sensitive than the chromatographic procedure, permitting reliable detection of Dgt activity at low dGTP substrate concentrations.
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Affiliation(s)
- Deepa Singh
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Roel M Schaaper
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Alejandro Hochkoeppler
- Department of Pharmacy and Biotechnology, University of Bologna, 40136 Bologna, Italy; CSGI, University of Firenze, 50019 Sesto Fiorentino, FI, Italy.
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30
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Rampazzo C, Tozzi MG, Dumontet C, Jordheim LP. The druggability of intracellular nucleotide-degrading enzymes. Cancer Chemother Pharmacol 2015; 77:883-93. [PMID: 26614508 DOI: 10.1007/s00280-015-2921-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 11/13/2015] [Indexed: 01/24/2023]
Abstract
Nucleotide metabolism is the target of a large number of anticancer drugs including antimetabolites and specific enzyme inhibitors. We review scientific findings that over the last 10-15 years have allowed the identification of several intracellular nucleotide-degrading enzymes as cancer drug targets, and discuss further potential therapeutic applications for Rcl, SAMHD1, MTH1 and cN-II. We believe that enzymes involved in nucleotide metabolism represent potent alternatives to conventional cancer chemotherapy targets.
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Affiliation(s)
- Chiara Rampazzo
- Department of Biology, University of Padova, 35131, Padua, Italy
| | - Maria Grazia Tozzi
- Department of Biology, Biochemistry Unit, University of Pisa, Pisa, Italy
| | - Charles Dumontet
- Université de Lyon, 69000, Lyon, France.,Université de Lyon 1, 69622, Lyon, France.,Université de Lyon 1, 69000, Lyon, France.,INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69000, Lyon, France.,CNRS UMR 5286, Centre de Recherche en Cancérologie de Lyon, 69000, Lyon, France.,Centre Léon Bérard, 69008, Lyon, France.,Hospices Civils de Lyon, 69000, Lyon, France
| | - Lars Petter Jordheim
- Université de Lyon, 69000, Lyon, France. .,Université de Lyon 1, 69622, Lyon, France. .,Université de Lyon 1, 69000, Lyon, France. .,INSERM U1052, Centre de Recherche en Cancérologie de Lyon, 69000, Lyon, France. .,CNRS UMR 5286, Centre de Recherche en Cancérologie de Lyon, 69000, Lyon, France. .,Centre Léon Bérard, 69008, Lyon, France. .,Equipe Anticorps-Anticancer, INSERM U1052 - CNRS UMR 5286, Faculté Rockefeller, Centre de Recherche en Cancérologie de Lyon, 8 avenue Rockefeller, 69008, Lyon, France.
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31
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Seamon KJ, Sun Z, Shlyakhtenko LS, Lyubchenko YL, Stivers JT. SAMHD1 is a single-stranded nucleic acid binding protein with no active site-associated nuclease activity. Nucleic Acids Res 2015; 43:6486-99. [PMID: 26101257 PMCID: PMC4513882 DOI: 10.1093/nar/gkv633] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 06/05/2015] [Indexed: 12/15/2022] Open
Abstract
The HIV-1 restriction factor SAMHD1 is a tetrameric enzyme activated by guanine nucleotides with dNTP triphosphate hydrolase activity (dNTPase). In addition to this established activity, there have been a series of conflicting reports as to whether the enzyme also possesses single-stranded DNA and/or RNA 3′-5′ exonuclease activity. SAMHD1 was purified using three chromatography steps, over which the DNase activity was largely separated from the dNTPase activity, but the RNase activity persisted. Surprisingly, we found that catalytic and nucleotide activator site mutants of SAMHD1 with no dNTPase activity retained the exonuclease activities. Thus, the exonuclease activity cannot be associated with any known dNTP binding site. Monomeric SAMHD1 was found to bind preferentially to single-stranded RNA, while the tetrameric form required for dNTPase action bound weakly. ssRNA binding, but not ssDNA, induces higher-order oligomeric states that are distinct from the tetrameric form that binds dNTPs. We conclude that the trace exonuclease activities detected in SAMHD1 preparations arise from persistent contaminants that co-purify with SAMHD1 and not from the HD active site. An in vivo model is suggested where SAMHD1 alternates between the mutually exclusive functions of ssRNA binding and dNTP hydrolysis depending on dNTP pool levels and the presence of viral ssRNA.
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Affiliation(s)
- Kyle J Seamon
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205-2185, USA
| | - Zhiqiang Sun
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Luda S Shlyakhtenko
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Yuri L Lyubchenko
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - James T Stivers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205-2185, USA
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