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Takahashi DT, Gadelle D, Agama K, Kiselev E, Zhang H, Yab E, Petrella S, Forterre P, Pommier Y, Mayer C. Topoisomerase I (TOP1) dynamics: conformational transition from open to closed states. Nat Commun 2022; 13:59. [PMID: 35013228 PMCID: PMC8748870 DOI: 10.1038/s41467-021-27686-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 11/17/2021] [Indexed: 12/24/2022] Open
Abstract
Eukaryotic topoisomerases I (TOP1) are ubiquitous enzymes removing DNA torsional stress. However, there is little data concerning the three-dimensional structure of TOP1 in the absence of DNA, nor how the DNA molecule can enter/exit its closed conformation. Here, we solved the structure of thermostable archaeal Caldiarchaeum subterraneum CsTOP1 in an apo-form. The enzyme displays an open conformation resulting from one substantial rotation between the capping (CAP) and the catalytic (CAT) modules. The junction between these two modules is a five-residue loop, the hinge, whose flexibility permits the opening/closing of the enzyme and the entry of DNA. We identified a highly conserved tyrosine near the hinge as mediating the transition from the open to closed conformation upon DNA binding. Directed mutagenesis confirmed the importance of the hinge flexibility, and linked the enzyme dynamics with sensitivity to camptothecin, a TOP1 inhibitor targeting the TOP1 enzyme catalytic site in the closed conformation. Topoisomerase I (TOP1) relaxes both positive and negative supercoils by nicking DNA and after rotation of the broken DNA strand closes the nick. Here, the authors present the DNA free crystal structure of TOP1 from the hyperthermophilic archaeon Caldiarchaeum subterraneum in the open form and discuss the mechanism of how DNA enters the catalytic site of TOP1.
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Affiliation(s)
- Diane T Takahashi
- Institut de Biologie Integrative de la Cellule, CNRS, Université Paris-Saclay, 91198, Gif sur Yvette, Cedex, France. .,Institut Pasteur, Université de Paris, CNRS UMR 3528, Unité de Microbiologie Structurale, F-75015, Paris, France. .,Biotechnology and Cell Signaling (CNRS/Université de Strasbourg, UMR 7242), Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, BP 10413, F-67412, Illkirch, France.
| | - Danièle Gadelle
- Institut de Biologie Integrative de la Cellule, CNRS, Université Paris-Saclay, 91198, Gif sur Yvette, Cedex, France
| | - Keli Agama
- Laboratory of Molecular Pharmacology, Developmental Therapeutics Branch, Center for Cancer Research, NCI, NIH, Bethesda, MD, 20892, USA
| | - Evgeny Kiselev
- Laboratory of Molecular Pharmacology, Developmental Therapeutics Branch, Center for Cancer Research, NCI, NIH, Bethesda, MD, 20892, USA
| | - Hongliang Zhang
- Laboratory of Molecular Pharmacology, Developmental Therapeutics Branch, Center for Cancer Research, NCI, NIH, Bethesda, MD, 20892, USA
| | - Emilie Yab
- Institut Pasteur, Université de Paris, CNRS UMR 3528, Unité de Microbiologie Structurale, F-75015, Paris, France
| | - Stephanie Petrella
- Institut Pasteur, Université de Paris, CNRS UMR 3528, Unité de Microbiologie Structurale, F-75015, Paris, France
| | - Patrick Forterre
- Institut de Biologie Integrative de la Cellule, CNRS, Université Paris-Saclay, 91198, Gif sur Yvette, Cedex, France
| | - Yves Pommier
- Laboratory of Molecular Pharmacology, Developmental Therapeutics Branch, Center for Cancer Research, NCI, NIH, Bethesda, MD, 20892, USA.
| | - Claudine Mayer
- Institut Pasteur, Université de Paris, CNRS UMR 3528, Unité de Microbiologie Structurale, F-75015, Paris, France.,Université de Paris, F-75013, Paris, France.,ICube-UMR7357, CSTB, Centre de Recherche en Biomédecine de Strasbourg, 67084, Strasbourg, France
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2
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Crewe M, Madabhushi R. Topoisomerase-Mediated DNA Damage in Neurological Disorders. Front Aging Neurosci 2021; 13:751742. [PMID: 34899270 PMCID: PMC8656403 DOI: 10.3389/fnagi.2021.751742] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 10/23/2021] [Indexed: 12/12/2022] Open
Abstract
The nervous system is vulnerable to genomic instability and mutations in DNA damage response factors lead to numerous developmental and progressive neurological disorders. Despite this, the sources and mechanisms of DNA damage that are most relevant to the development of neuronal dysfunction are poorly understood. The identification of primarily neurological abnormalities in patients with mutations in TDP1 and TDP2 suggest that topoisomerase-mediated DNA damage could be an important underlying source of neuronal dysfunction. Here we review the potential sources of topoisomerase-induced DNA damage in neurons, describe the cellular mechanisms that have evolved to repair such damage, and discuss the importance of these repair mechanisms for preventing neurological disorders.
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Affiliation(s)
| | - Ram Madabhushi
- Departments of Psychiatry, Neuroscience, and Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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3
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Flor A, Wolfgeher D, Li J, Hanakahi LA, Kron SJ. Lipid-derived electrophiles mediate the effects of chemotherapeutic topoisomerase I poisons. Cell Chem Biol 2021; 28:776-787.e8. [PMID: 33352117 PMCID: PMC8206239 DOI: 10.1016/j.chembiol.2020.11.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 10/13/2020] [Accepted: 11/25/2020] [Indexed: 12/19/2022]
Abstract
Topoisomerase 1 (Top1) reversibly nicks chromosomal DNA to relax strain accumulated during transcription, replication, chromatin assembly, and chromosome condensation. The Top1 poison camptothecin targets cancer cells by trapping the enzyme in the covalent complex Top1cc, tethered to cleaved DNA by a tyrosine-3'-phosphate bond. In vitro mechanistic studies point to interfacial inhibition, where camptothecin binding to the Top1-DNA interface stabilizes Top1cc. Here we present a complementary covalent mechanism that is critical in vivo. We observed that camptothecins induce oxidative stress, leading to lipid peroxidation, lipid-derived electrophile accumulation, and Top1 poisoning via covalent modification. The electrophile 4-hydroxy-2-nonenal can induce Top1cc on its own and forms a Michael adduct to a cysteine thiol in the Top1 active site, potentially blocking tyrosine dephosphorylation and 3' DNA phosphate release. Thereby, camptothecins may leverage a physiological cysteine-based redox switch in Top1 to mediate their selective toxicity to rapidly proliferating cancer cells.
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Affiliation(s)
- Amy Flor
- University of Chicago, Department of Molecular Genetics and Cell Biology, Chicago IL 60637, USA,Further information and requests for resources and reagents should be directed to and will be fulfilled by the Lead Contact, Amy Flor ()
| | - Donald Wolfgeher
- University of Chicago, Department of Molecular Genetics and Cell Biology, Chicago IL 60637, USA
| | - Jing Li
- University of Illinois Chicago, College of Pharmacy, Department of Pharmaceutical Sciences, Rockford IL 61107, USA
| | - Leslyn A. Hanakahi
- University of Illinois Chicago, College of Pharmacy, Department of Pharmaceutical Sciences, Rockford IL 61107, USA
| | - Stephen J. Kron
- University of Chicago, Department of Molecular Genetics and Cell Biology, Chicago IL 60637, USA,Corresponding author: 929 E. 57th St. W522A, Chicago IL 60637, USA;
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4
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He X, Wang P, Wang Y. Mitochondrial Transcription Factor A Binds to and Promotes Mutagenic Transcriptional Bypass of O4-Alkylthymidine Lesions. Anal Chem 2021; 93:1161-1169. [PMID: 33290046 PMCID: PMC7904241 DOI: 10.1021/acs.analchem.0c04224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
O2- and O4-alkylated thymidine lesions are known to be poorly repaired and persist in mammalian tissues. To understand how mammalian cells sense the presence and regulate the repair of these lesions, we employed a quantitative proteomic method to discover regioisomeric O2- and O4-n-butylthymidine (O2- and O4-nBudT)-binding proteins. We were able to identify 21 and 74 candidate DNA damage recognition proteins for O2-nBudT- and O4-nBudT-bearing DNA probes, respectively. Among these proteins, DDB1 and DDB2 selectively bind to O2-nBudT-containing DNA, whereas three high-mobility group (HMG) proteins (i.e., HMGB1, HMGB2, and mitochondrial transcription factor A (TFAM)) exhibit preferential binding to O4-nBudT-bearing DNA. We further demonstrated that TFAM binds directly and selectively with O4-alkyldT-harboring DNA, and the binding capacity depends mainly on the HMG box-A domain of TFAM. We also found that TFAM promotes transcriptional mutagenesis of O4-nBudT and O4-pyridyloxobutylthymidine, which is a DNA adduct induced by tobacco-specific N-nitrosamines, in vitro and in human cells. Together, we explored, for the first time, the interaction proteomes of O-alkyldT lesions, and our study expanded the functions of TFAM by revealing its capability in the recognition of O4-alkyldT-bearing DNA and uncovering its modulation of transcriptional mutagenesis of these lesions in human cells.
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Affiliation(s)
- Xiaomei He
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Pengcheng Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
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5
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Lebedeva NA, Rechkunova NI, Endutkin AV, Lavrik OI. Apurinic/Apyrimidinic Endonuclease 1 and Tyrosyl-DNA Phosphodiesterase 1 Prevent Suicidal Covalent DNA-Protein Crosslink at Apurinic/Apyrimidinic Site. Front Cell Dev Biol 2021; 8:617301. [PMID: 33505969 PMCID: PMC7833210 DOI: 10.3389/fcell.2020.617301] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 11/30/2020] [Indexed: 12/12/2022] Open
Abstract
Bifunctional 8-oxoguanine-DNA glycosylase (OGG1), a crucial DNA-repair enzyme, removes from DNA 8-oxo-7,8-dihydroguanine (8-oxoG) with following cleavage of the arising apurinic/apyrimidinic (AP) site. The major enzyme in eukaryotic cells that catalyzes the cleavage of AP sites is AP endonuclease 1 (APE1). Alternatively, AP sites can be cleaved by tyrosyl-DNA phosphodiesterase 1 (TDP1) to initiate APE1-independent repair, thus expanding the ability of the base excision repair (BER) process. Poly(ADP-ribose) polymerase 1 (PARP1) is a regulatory protein of DNA repair. PARP2 is also activated in response to DNA damage and can be regarded as the BER participant. Here we analyze PARP1 and PARP2 interactions with DNA intermediates of the initial stages of the BER process (8-oxoG and AP-site containing DNA) and their interplay with the proteins recognizing and processing these DNA structures focusing on OGG1. OGG1 as well as PARP1 and PARP2 form covalent complex with AP site-containing DNA without borohydride reduction. AP site incision by APE1 or TDP1 removal of protein adducts but not proteins’ PARylation prevent DNA-protein crosslinks.
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Affiliation(s)
- Natalia A Lebedeva
- Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | | | - Anton V Endutkin
- Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Olga I Lavrik
- Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia.,Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
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6
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Sun Y, Saha LK, Saha S, Jo U, Pommier Y. Debulking of topoisomerase DNA-protein crosslinks (TOP-DPC) by the proteasome, non-proteasomal and non-proteolytic pathways. DNA Repair (Amst) 2020; 94:102926. [DOI: 10.1016/j.dnarep.2020.102926] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 01/24/2023]
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7
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Sun Y, Saha S, Wang W, Saha LK, Huang SYN, Pommier Y. Excision repair of topoisomerase DNA-protein crosslinks (TOP-DPC). DNA Repair (Amst) 2020; 89:102837. [PMID: 32200233 DOI: 10.1016/j.dnarep.2020.102837] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/22/2020] [Accepted: 02/25/2020] [Indexed: 12/13/2022]
Abstract
Topoisomerases are essential enzymes solving DNA topological problems such as supercoils, knots and catenanes that arise from replication, transcription, chromatin remodeling and other nucleic acid metabolic processes. They are also the targets of widely used anticancer drugs (e.g. topotecan, irinotecan, enhertu, etoposide, doxorubicin, mitoxantrone) and fluoroquinolone antibiotics (e.g. ciprofloxacin and levofloxacin). Topoisomerases manipulate DNA topology by cleaving one DNA strand (TOP1 and TOP3 enzymes) or both in concert (TOP2 enzymes) through the formation of transient enzyme-DNA cleavage complexes (TOPcc) with phosphotyrosyl linkages between DNA ends and the catalytic tyrosyl residue of the enzymes. Failure in the self-resealing of TOPcc results in persistent TOPcc (which we refer it to as topoisomerase DNA-protein crosslinks (TOP-DPC)) that threaten genome integrity and lead to cancers and neurodegenerative diseases. The cell prevents the accumulation of topoisomerase-mediated DNA damage by excising TOP-DPC and ligating the associated breaks using multiple pathways conserved in eukaryotes. Tyrosyl-DNA phosphodiesterases (TDP1 and TDP2) cleave the tyrosyl-DNA bonds whereas structure-specific endonucleases such as Mre11 and XPF (Rad1) incise the DNA phosphodiester backbone to remove the TOP-DPC along with the adjacent DNA segment. The proteasome and metalloproteases of the WSS1/Spartan family typify proteolytic repair pathways that debulk TOP-DPC to make the peptide-DNA bonds accessible to the TDPs and endonucleases. The purpose of this review is to summarize our current understanding of how the cell excises TOP-DPC and why, when and where the cell recruits one specific mechanism for repairing topoisomerase-mediated DNA damage, acquiring resistance to therapeutic topoisomerase inhibitors and avoiding genomic instability, cancers and neurodegenerative diseases.
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Affiliation(s)
- Yilun Sun
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Sourav Saha
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Wenjie Wang
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Liton Kumar Saha
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Shar-Yin Naomi Huang
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States.
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8
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Gmeiner WH. Entrapment of DNA topoisomerase-DNA complexes by nucleotide/nucleoside analogs. CANCER DRUG RESISTANCE (ALHAMBRA, CALIF.) 2019; 2:994-1001. [PMID: 31930190 PMCID: PMC6953902 DOI: 10.20517/cdr.2019.95] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 11/22/2019] [Accepted: 11/29/2019] [Indexed: 06/10/2023]
Abstract
Topoisomerases are well-validated targets for cancer chemotherapy and DNA topoisomerase 1 (Top1) is the sole target of the camptothecin (CPT) class of anticancer drugs. Over the last 20 years, multiple studies have shown Top1 activity is modulated by non-native DNA structures and this can lead to trapping of Top1 cleavage complexes (Top1cc) and conversion to DNA double strand breaks. Among the perturbations to DNA structure that generate Top1cc are nucleoside analogs that are incorporated into genomic DNA during replication including cytarabine, gemcitabine, and 5-fluoro-2'-deoxyuridine (FdU). We review the literature summarizing the role of Top1cc in mediating the DNA damaging and cytotoxic activities of nucleoside analogs. We also summarize studies demonstrating distinct differences between Top1cc induced by nucleoside analogs and CPTs, particularly with regard to DNA repair. Collectively, these studies demonstrate that, while Top1 is a common target for both Top1 poisons such as CPT and nucleoside analogs such as FdU, these agents are not redundant. In recent years, studies have shown that Top1 poisons and nucleoside analogs together with other anti-cancer drugs such as cisplatin cause replication stress and the DNA repair pathways that modulate the cytotoxic activities of these compounds are being elucidated. We present an overview of this evolving literature, which has implications for how targeting of Top1 with nucleoside analogs can be used more effectively for cancer treatment.
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Affiliation(s)
- William H. Gmeiner
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
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9
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Gruber DR, Toner JJ, Miears HL, Shernyukov AV, Kiryutin AS, Lomzov AA, Endutkin AV, Grin IR, Petrova DV, Kupryushkin MS, Yurkovskaya AV, Johnson EC, Okon M, Bagryanskaya EG, Zharkov DO, Smirnov SL. Oxidative damage to epigenetically methylated sites affects DNA stability, dynamics and enzymatic demethylation. Nucleic Acids Res 2019; 46:10827-10839. [PMID: 30289469 PMCID: PMC6237784 DOI: 10.1093/nar/gky893] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 09/20/2018] [Indexed: 01/20/2023] Open
Abstract
DNA damage can affect various regulatory elements of the genome, with the consequences for DNA structure, dynamics, and interaction with proteins remaining largely unexplored. We used solution NMR spectroscopy, restrained and free molecular dynamics to obtain the structures and investigate dominant motions for a set of DNA duplexes containing CpG sites permuted with combinations of 5-methylcytosine (mC), the primary epigenetic base, and 8-oxoguanine (oxoG), an abundant DNA lesion. Guanine oxidation significantly changed the motion in both hemimethylated and fully methylated DNA, increased base pair breathing, induced BI→BII transition in the backbone 3′ to the oxoG and reduced the variability of shift and tilt helical parameters. UV melting experiments corroborated the NMR and molecular dynamics results, showing significant destabilization of all methylated contexts by oxoG. Notably, some dynamic and thermodynamic effects were not additive in the fully methylated oxidized CpG, indicating that the introduced modifications interact with each other. Finally, we show that the presence of oxoG biases the recognition of methylated CpG dinucleotides by ROS1, a plant enzyme involved in epigenetic DNA demethylation, in favor of the oxidized DNA strand. Thus, the conformational and dynamic effects of spurious DNA oxidation in the regulatory CpG dinucleotide can have far-reaching biological consequences.
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Affiliation(s)
- David R Gruber
- Chemistry Department, Western Washington University, 516 High St., Bellingham, WA 98225-9150, USA
| | - Joanna J Toner
- Chemistry Department, Western Washington University, 516 High St., Bellingham, WA 98225-9150, USA
| | - Heather L Miears
- Chemistry Department, Western Washington University, 516 High St., Bellingham, WA 98225-9150, USA
| | - Andrey V Shernyukov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Lavrentieva Ave., Novosibirsk 630090, Russia.,Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia
| | - Alexey S Kiryutin
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia.,SB RAS International Tomography Center, 3a Institutskaya St., Novosibirsk 630090, Russia
| | - Alexander A Lomzov
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia.,SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Anton V Endutkin
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia.,SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Inga R Grin
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia.,SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Darya V Petrova
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia.,SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Maxim S Kupryushkin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Alexandra V Yurkovskaya
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia.,SB RAS International Tomography Center, 3a Institutskaya St., Novosibirsk 630090, Russia
| | | | - Mark Okon
- Department of Biochemistry and Molecular Biology, Department of Chemistry, and Michael Smith Laboratories, University of British Columbia, Vancouver BC, V6T 1Z3, Canada
| | - Elena G Bagryanskaya
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Lavrentieva Ave., Novosibirsk 630090, Russia.,Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia
| | - Dmitry O Zharkov
- Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia.,SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Serge L Smirnov
- Chemistry Department, Western Washington University, 516 High St., Bellingham, WA 98225-9150, USA
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10
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Jakobsen KP, Andersen AH, Bjergbæk L. Abortive activity of Topoisomerase I: a challenge for genome integrity? Curr Genet 2019; 65:1141-1144. [DOI: 10.1007/s00294-019-00984-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/24/2019] [Accepted: 04/25/2019] [Indexed: 01/19/2023]
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11
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Mouly L, Mamouni K, Gence R, Cristini A, Cherier J, Castinel A, Legrand M, Favre G, Sordet O, Monferran S. PARP-1-dependent RND1 transcription induced by topoisomerase I cleavage complexes confers cellular resistance to camptothecin. Cell Death Dis 2018; 9:931. [PMID: 30209297 PMCID: PMC6135836 DOI: 10.1038/s41419-018-0981-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/02/2018] [Accepted: 08/20/2018] [Indexed: 02/02/2023]
Abstract
RHO GTPases regulate essential functions such as the organization of the actin cytoskeleton. The classic members cycle between an active GTP-bound and an inactive GDP-bound conformation whereas atypical members are predominantly GTP-bound. Besides their well-established role, the classic RHO GTPases RHOB and RAC1, are rapidly induced and/or activated by genotoxic stress and contribute to the DNA damage response. Here we used camptothecin, a selective topoisomerase I (TOP1) inhibitor that stabilizes TOP1 cleavage complexes (TOP1cc), to search for other potential early DNA damage-inducible RHO GTPase genes. We identified that an atypical RHO GTPase, RND1, is rapidly induced by camptothecin. RND1 induction is closely associated with the presence of TOP1cc induced by camptothecin or by DNA lesions that elevate TOP1cc levels such as UV and hydrogen peroxide. We further demonstrated that camptothecin increases RND1 gene transcription and mRNA stability. Camptothecin also increases poly(ADP-ribose) polymerase 1 (PARP-1) activity, whose inhibition reduces RND1 transcription. In addition, overexpression of RND1 increases PARP-1, suggesting a cross-talk between PARP-1 and RND1. Finally, RND1 protects cells against camptothecin-induced apoptosis, and hence favors cellular resistance to camptothecin. Together, these findings highlight RND1 as an atypical RHO GTPase early induced by TOP1cc, and show that the TOP1cc-PARP-1-RND1 pathway protects cells against apoptosis induced by camptothecin.
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Affiliation(s)
- Laetitia Mouly
- Cancer Research Center of Toulouse (CRCT), INSERM, Université de Toulouse, Université Toulouse III Paul Sabatier, CNRS, Toulouse, France.,Faculté des Sciences Pharmaceutiques, Université de Toulouse, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Kenza Mamouni
- Cancer Research Center of Toulouse (CRCT), INSERM, Université de Toulouse, Université Toulouse III Paul Sabatier, CNRS, Toulouse, France.,Faculté des Sciences Pharmaceutiques, Université de Toulouse, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Remi Gence
- Cancer Research Center of Toulouse (CRCT), INSERM, Université de Toulouse, Université Toulouse III Paul Sabatier, CNRS, Toulouse, France.,Faculté des Sciences Pharmaceutiques, Université de Toulouse, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Agnese Cristini
- Cancer Research Center of Toulouse (CRCT), INSERM, Université de Toulouse, Université Toulouse III Paul Sabatier, CNRS, Toulouse, France.,Faculté des Sciences Pharmaceutiques, Université de Toulouse, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Julia Cherier
- Cancer Research Center of Toulouse (CRCT), INSERM, Université de Toulouse, Université Toulouse III Paul Sabatier, CNRS, Toulouse, France
| | - Adrien Castinel
- Faculté des Sciences Pharmaceutiques, Université de Toulouse, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Morgane Legrand
- Faculté des Sciences Pharmaceutiques, Université de Toulouse, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Gilles Favre
- Cancer Research Center of Toulouse (CRCT), INSERM, Université de Toulouse, Université Toulouse III Paul Sabatier, CNRS, Toulouse, France.,Faculté des Sciences Pharmaceutiques, Université de Toulouse, Université Toulouse III Paul Sabatier, Toulouse, France
| | - Olivier Sordet
- Cancer Research Center of Toulouse (CRCT), INSERM, Université de Toulouse, Université Toulouse III Paul Sabatier, CNRS, Toulouse, France.
| | - Sylvie Monferran
- Cancer Research Center of Toulouse (CRCT), INSERM, Université de Toulouse, Université Toulouse III Paul Sabatier, CNRS, Toulouse, France. .,Faculté des Sciences Pharmaceutiques, Université de Toulouse, Université Toulouse III Paul Sabatier, Toulouse, France.
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12
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Arthur DE, Uzairu A. Molecular docking study and structure-based design of novel camptothecin analogues used as topoisomerase I inhibitor. J CHIN CHEM SOC-TAIP 2018. [DOI: 10.1002/jccs.201700314] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- David Ebuka Arthur
- Department of Chemistry; Ahmadu Bello University; Zaria Kaduna State Nigeria
| | - Adamu Uzairu
- Department of Chemistry; Ahmadu Bello University; Zaria Nigeria
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13
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Delgado JL, Hsieh CM, Chan NL, Hiasa H. Topoisomerases as anticancer targets. Biochem J 2018; 475:373-398. [PMID: 29363591 PMCID: PMC6110615 DOI: 10.1042/bcj20160583] [Citation(s) in RCA: 264] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 12/14/2017] [Accepted: 12/21/2017] [Indexed: 12/15/2022]
Abstract
Many cancer type-specific anticancer agents have been developed and significant advances have been made toward precision medicine in cancer treatment. However, traditional or nonspecific anticancer drugs are still important for the treatment of many cancer patients whose cancers either do not respond to or have developed resistance to cancer-specific anticancer agents. DNA topoisomerases, especially type IIA topoisomerases, are proved therapeutic targets of anticancer and antibacterial drugs. Clinically successful topoisomerase-targeting anticancer drugs act through topoisomerase poisoning, which leads to replication fork arrest and double-strand break formation. Unfortunately, this unique mode of action is associated with the development of secondary cancers and cardiotoxicity. Structures of topoisomerase-drug-DNA ternary complexes have revealed the exact binding sites and mechanisms of topoisomerase poisons. Recent advances in the field have suggested a possibility of designing isoform-specific human topoisomerase II poisons, which may be developed as safer anticancer drugs. It may also be possible to design catalytic inhibitors of topoisomerases by targeting certain inactive conformations of these enzymes. Furthermore, identification of various new bacterial topoisomerase inhibitors and regulatory proteins may inspire the discovery of novel human topoisomerase inhibitors. Thus, topoisomerases remain as important therapeutic targets of anticancer agents.
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Affiliation(s)
- Justine L Delgado
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, 115 S Grand Ave., S321 Pharmacy Building, Iowa City, IA 52242, U.S.A
| | - Chao-Ming Hsieh
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei City 100, Taiwan
| | - Nei-Li Chan
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei City 100, Taiwan
| | - Hiroshi Hiasa
- Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455, U.S.A.
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14
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Chiang SC, Meagher M, Kassouf N, Hafezparast M, McKinnon PJ, Haywood R, El-Khamisy SF. Mitochondrial protein-linked DNA breaks perturb mitochondrial gene transcription and trigger free radical-induced DNA damage. SCIENCE ADVANCES 2017; 3:e1602506. [PMID: 28508041 PMCID: PMC5409496 DOI: 10.1126/sciadv.1602506] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/02/2017] [Indexed: 05/06/2023]
Abstract
Breakage of one strand of DNA is the most common form of DNA damage. Most damaged DNA termini require end-processing in preparation for ligation. The importance of this step is highlighted by the association of defects in the 3'-end processing enzyme tyrosyl DNA phosphodiesterase 1 (TDP1) and neurodegeneration and by the cytotoxic induction of protein-linked DNA breaks (PDBs) and oxidized nucleic acid intermediates during chemotherapy and radiotherapy. Although much is known about the repair of PDBs in the nucleus, little is known about this process in the mitochondria. We reveal that TDP1 resolves mitochondrial PDBs (mtPDBs), thereby promoting mitochondrial gene transcription. Overexpression of a toxic form of mitochondrial topoisomerase I (TOP1mt*), which generates excessive mtPDBs, results in a TDP1-dependent compensatory up-regulation of mitochondrial gene transcription. In the absence of TDP1, the imbalance in transcription of mitochondrial- and nuclear-encoded electron transport chain (ETC) subunits results in misassembly of ETC complex III. Bioenergetics profiling further reveals that TDP1 promotes oxidative phosphorylation under both basal and high energy demands. It is known that mitochondrial dysfunction results in free radical leakage and nuclear DNA damage; however, the detection of intermediates of radical damage to DNA is yet to be shown. Consequently, we report an increased accumulation of carbon-centered radicals in cells lacking TDP1, using electron spin resonance spectroscopy. Overexpression of the antioxidant enzyme superoxide dismutase 1 (SOD1) reduces carbon-centered adducts and protects TDP1-deficient cells from oxidative stress. Conversely, overexpression of the amyotrophic lateral sclerosis-associated mutant SOD1G93A leads to marked sensitivity. Whereas Tdp1 knockout mice develop normally, overexpression of SOD1G93A suggests early embryonic lethality. Together, our data show that TDP1 resolves mtPDBs, thereby regulating mitochondrial gene transcription and oxygen consumption by oxidative phosphorylation, thus conferring cellular protection against reactive oxygen species-induced damage.
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Affiliation(s)
- Shih-Chieh Chiang
- Krebs Institute and Sheffield Institute for Nucleic Acids, Department of Molecular Biology and Biotechnology, Firth Court, University of Sheffield, S10 2TN Sheffield, U.K
| | - Martin Meagher
- Wellcome Trust Centre for Mitochondrial Research, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, U.K
| | - Nick Kassouf
- RAFT Institute, Mount Vernon Hospital, Northwood, Middlesex HA6 2RN, U.K
| | - Majid Hafezparast
- School of Life Sciences, University of Sussex, Brighton BN1 9QG, U.K
| | - Peter J. McKinnon
- Department of Genetics, St. Jude Children’s Research Hospital, Memphis, TN 38105–3678, USA
| | - Rachel Haywood
- RAFT Institute, Mount Vernon Hospital, Northwood, Middlesex HA6 2RN, U.K
| | - Sherif F. El-Khamisy
- Krebs Institute and Sheffield Institute for Nucleic Acids, Department of Molecular Biology and Biotechnology, Firth Court, University of Sheffield, S10 2TN Sheffield, U.K
- Center for Genomics, Helmy Institute for Medical Sciences, Zewail City of Science and Technology, Giza 12588, Egypt
- Corresponding author.
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15
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Esadze A, Rodriguez G, Cravens SL, Stivers JT. AP-Endonuclease 1 Accelerates Turnover of Human 8-Oxoguanine DNA Glycosylase by Preventing Retrograde Binding to the Abasic-Site Product. Biochemistry 2017; 56:1974-1986. [PMID: 28345889 DOI: 10.1021/acs.biochem.7b00017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A major product of oxidative DNA damage is 8-oxoguanine. In humans, 8-oxoguanine DNA glycosylase (hOGG1) facilitates removal of these lesions, producing an abasic (AP) site in the DNA that is subsequently incised by AP-endonuclease 1 (APE1). APE1 stimulates turnover of several glycosylases by accelerating rate-limiting product release. However, there have been conflicting accounts of whether hOGG1 follows a similar mechanism. In pre-steady-state kinetic measurements, we found that addition of APE1 had no effect on the rapid burst phase of 8-oxoguanine excision by hOGG1 but accelerated steady-state turnover (kcat) by ∼10-fold. The stimulation by APE1 required divalent cations, could be detected under multiple-turnover conditions using limiting concentrations of APE1, did not require flanking DNA surrounding the hOGG1 lesion site, and occurred efficiently even when the first 49 residues of APE1's N-terminus had been deleted. Stimulation by APE1 does not involve relief from product inhibition because thymine DNA glycosylase, an enzyme that binds more tightly to AP sites than hOGG1 does, could not effectively substitute for APE1. A stimulation mechanism involving stable protein-protein interactions between free APE1 and hOGG1, or the DNA-bound forms, was excluded using protein cross-linking assays. The combined results indicate a mechanism whereby dynamic excursions of hOGG1 from the AP site allow APE1 to invade the site and rapidly incise the phosphate backbone. This mechanism, which allows APE1 to access the AP site without forming specific interactions with the glycosylase, is a simple and elegant solution to passing along unstable intermediates in base excision repair.
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Affiliation(s)
- Alexandre Esadze
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine , 725 North Wolfe Street, Baltimore, Maryland 21205-2185, United States
| | - Gaddiel Rodriguez
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine , 725 North Wolfe Street, Baltimore, Maryland 21205-2185, United States
| | - Shannen L Cravens
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine , 725 North Wolfe Street, Baltimore, Maryland 21205-2185, United States
| | - James T Stivers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine , 725 North Wolfe Street, Baltimore, Maryland 21205-2185, United States
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16
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Hoppins JJ, Gruber DR, Miears HL, Kiryutin AS, Kasymov RD, Petrova DV, Endutkin AV, Popov AV, Yurkovskaya AV, Fedechkin SO, Brockerman JA, Zharkov DO, Smirnov SL. 8-Oxoguanine Affects DNA Backbone Conformation in the EcoRI Recognition Site and Inhibits Its Cleavage by the Enzyme. PLoS One 2016; 11:e0164424. [PMID: 27749894 PMCID: PMC5066940 DOI: 10.1371/journal.pone.0164424] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/23/2016] [Indexed: 12/13/2022] Open
Abstract
8-oxoguanine is one of the most abundant and impactful oxidative DNA lesions. However, the reasons underlying its effects, especially those not directly explained by the altered base pairing ability, are poorly understood. We report the effect of the lesion on the action of EcoRI, a widely used restriction endonuclease. Introduction of 8-oxoguanine inside, or adjacent to, the GAATTC recognition site embedded within the Drew—Dickerson dodecamer sequence notably reduced the EcoRI activity. Solution NMR revealed that 8-oxoguanine in the DNA duplex causes substantial alterations in the sugar—phosphate backbone conformation, inducing a BI→BII transition. Moreover, molecular dynamics of the complex suggested that 8-oxoguanine, although does not disrupt the sequence-specific contacts formed by the enzyme with DNA, shifts the distribution of BI/BII backbone conformers. Based on our data, we propose that the disruption of enzymatic cleavage can be linked with the altered backbone conformation and dynamics in the free oxidized DNA substrate and, possibly, at the protein—DNA interface.
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Affiliation(s)
- Joanna J. Hoppins
- Chemistry Department, Western Washington University, Bellingham, WA, United States of America
| | - David R. Gruber
- Chemistry Department, Western Washington University, Bellingham, WA, United States of America
| | - Heather L. Miears
- Chemistry Department, Western Washington University, Bellingham, WA, United States of America
| | - Alexey S. Kiryutin
- SB RAS International Tomography Center, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | - Rustem D. Kasymov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
- Institute of Biochemistry, Stuttgart University, Stuttgart, Germany
| | - Darya V. Petrova
- Novosibirsk State University, Novosibirsk, Russia
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Anton V. Endutkin
- Novosibirsk State University, Novosibirsk, Russia
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Alexander V. Popov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Alexandra V. Yurkovskaya
- SB RAS International Tomography Center, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | - Stanislav O. Fedechkin
- Chemistry Department, Western Washington University, Bellingham, WA, United States of America
- University of California Santa Cruz, Program in Biomedical Science and Engineering, Santa Cruz, CA, United States of America
| | - Jacob A. Brockerman
- Chemistry Department, Western Washington University, Bellingham, WA, United States of America
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Dmitry O. Zharkov
- Novosibirsk State University, Novosibirsk, Russia
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
- * E-mail: (SLS); (DOZ)
| | - Serge L. Smirnov
- Chemistry Department, Western Washington University, Bellingham, WA, United States of America
- * E-mail: (SLS); (DOZ)
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17
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Pommier Y, Sun Y, Huang SYN, Nitiss JL. Roles of eukaryotic topoisomerases in transcription, replication and genomic stability. Nat Rev Mol Cell Biol 2016; 17:703-721. [DOI: 10.1038/nrm.2016.111] [Citation(s) in RCA: 540] [Impact Index Per Article: 67.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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18
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Abstract
TDP1 and TDP2 were discovered and named based on the fact they process 3'- and 5'-DNA ends by excising irreversible protein tyrosyl-DNA complexes involving topoisomerases I and II, respectively. Yet, both enzymes have an extended spectrum of activities. TDP1 not only excises trapped topoisomerases I (Top1 in the nucleus and Top1mt in mitochondria), but also repairs oxidative damage-induced 3'-phosphoglycolates and alkylation damage-induced DNA breaks, and excises chain terminating anticancer and antiviral nucleosides in the nucleus and mitochondria. The repair function of TDP2 is devoted to the excision of topoisomerase II- and potentially topoisomerases III-DNA adducts. TDP2 is also essential for the life cycle of picornaviruses (important human and bovine pathogens) as it unlinks VPg proteins from the 5'-end of the viral RNA genome. Moreover, TDP2 has been involved in signal transduction (under the former names of TTRAP or EAPII). The DNA repair partners of TDP1 include PARP1, XRCC1, ligase III and PNKP from the base excision repair (BER) pathway. By contrast, TDP2 repair functions are coordinated with Ku and ligase IV in the non-homologous end joining pathway (NHEJ). This article summarizes and compares the biochemistry, functions, and post-translational regulation of TDP1 and TDP2, as well as the relevance of TDP1 and TDP2 as determinants of response to anticancer agents. We discuss the rationale for developing TDP inhibitors for combinations with topoisomerase inhibitors (topotecan, irinotecan, doxorubicin, etoposide, mitoxantrone) and DNA damaging agents (temozolomide, bleomycin, cytarabine, and ionizing radiation), and as novel antiviral agents.
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Affiliation(s)
- Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA.
| | - Shar-yin N Huang
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA
| | - Rui Gao
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA
| | - Benu Brata Das
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA; Laboratory of Molecular Biology, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Junko Murai
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA; Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshidakonoe, Sakyo-ku 606-8501, Japan
| | - Christophe Marchand
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA
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19
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Wallace BD, Redinbo MR. The human microbiome is a source of therapeutic drug targets. Curr Opin Chem Biol 2013; 17:379-84. [PMID: 23680493 DOI: 10.1016/j.cbpa.2013.04.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 04/02/2013] [Accepted: 04/09/2013] [Indexed: 12/13/2022]
Abstract
It was appreciated early in drug discovery that the microbiota play an important role in the efficacy of therapeutic compounds. Indeed, the first antibiotic sulfa drugs were shown in the 1940s to be transformed by the bacteria that encode what we now call the intestinal microbiome. Here we briefly review the roles symbiotic bacteria play in the chemistry of human health, and we focus on the emerging appreciation that specific enzyme targets expressed by microbial symbiotes can be selectively disrupted to achieve clinical outcomes. We conclude that components of the microbiome should be considered 'druggable targets,' and we suggest that our rapidly evolving understanding of the chemical biology of mammalian-microbial symbiosis will translate into improved human health.
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Affiliation(s)
- Bret D Wallace
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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20
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Khadka DB, Cho WJ. Topoisomerase inhibitors as anticancer agents: a patent update. Expert Opin Ther Pat 2013; 23:1033-56. [DOI: 10.1517/13543776.2013.790958] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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21
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Jeppesen DK, Bohr VA, Stevnsner T. DNA repair deficiency in neurodegeneration. Prog Neurobiol 2011; 94:166-200. [PMID: 21550379 DOI: 10.1016/j.pneurobio.2011.04.013] [Citation(s) in RCA: 243] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/18/2011] [Accepted: 04/22/2011] [Indexed: 01/17/2023]
Abstract
Deficiency in repair of nuclear and mitochondrial DNA damage has been linked to several neurodegenerative disorders. Many recent experimental results indicate that the post-mitotic neurons are particularly prone to accumulation of unrepaired DNA lesions potentially leading to progressive neurodegeneration. Nucleotide excision repair is the cellular pathway responsible for removing helix-distorting DNA damage and deficiency in such repair is found in a number of diseases with neurodegenerative phenotypes, including Xeroderma Pigmentosum and Cockayne syndrome. The main pathway for repairing oxidative base lesions is base excision repair, and such repair is crucial for neurons given their high rates of oxygen metabolism. Mismatch repair corrects base mispairs generated during replication and evidence indicates that oxidative DNA damage can cause this pathway to expand trinucleotide repeats, thereby causing Huntington's disease. Single-strand breaks are common DNA lesions and are associated with the neurodegenerative diseases, ataxia-oculomotor apraxia-1 and spinocerebellar ataxia with axonal neuropathy-1. DNA double-strand breaks are toxic lesions and two main pathways exist for their repair: homologous recombination and non-homologous end-joining. Ataxia telangiectasia and related disorders with defects in these pathways illustrate that such defects can lead to early childhood neurodegeneration. Aging is a risk factor for neurodegeneration and accumulation of oxidative mitochondrial DNA damage may be linked with the age-associated neurodegenerative disorders Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. Mutation in the WRN protein leads to the premature aging disease Werner syndrome, a disorder that features neurodegeneration. In this article we review the evidence linking deficiencies in the DNA repair pathways with neurodegeneration.
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Affiliation(s)
- Dennis Kjølhede Jeppesen
- Danish Centre for Molecular Gerontology and Danish Aging Research Center, University of Aarhus, Department of Molecular Biology, Aarhus, Denmark
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22
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Ricci A, Marinello J, Bortolus M, Sánchez A, Grandas A, Pedroso E, Pommier Y, Capranico G, Maniero AL, Zagotto G. Electron paramagnetic resonance (EPR) study of spin-labeled camptothecin derivatives: a different look of the ternary complex. J Med Chem 2011; 54:1003-9. [PMID: 21254781 DOI: 10.1021/jm101232t] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Camptothecin (CPT) derivatives are clinically effective poisons of DNA topoisomerase I (Top1) able to form a ternary complex with the Top1-DNA complex. The aim of this investigation was to examine the dynamic aspects of the ternary complex formation by means of site-directed spin labeling electron paramagnetic resonance (SDSL-EPR). Two semisynthetic CPT derivatives bearing the paramagnetic moiety were synthesized, and their biological activity was tested. A 22-mer DNA oligonucleotide sequence with high affinity cleavage site for Top1 was also synthesized. EPR experiments were carried out on modified CPT in the presence of DNA, of Top1, or of both. In the last case, a slow motion component in the EPR signal appeared, indicating the formation of the ternary complex. Deconvolution of the EPR spectrum allowed to obtain the relative drug amounts in the complex. It was also possible to demonstrate that the residence time of CPT "trapped" in the ternary complex is longer than hundreds of microseconds.
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Affiliation(s)
- Antonio Ricci
- Department of Pharmaceutical Sciences, University of Padova, Via Marzolo 5, 30039 Padova, Italy
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23
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Khadka DB, Cho WJ. 3-Arylisoquinolines as novel topoisomerase I inhibitors. Bioorg Med Chem 2011; 19:724-34. [DOI: 10.1016/j.bmc.2010.10.057] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 10/27/2010] [Accepted: 10/28/2010] [Indexed: 12/22/2022]
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24
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Vassallo O, Castelli S, D'Annessa I, della Rocca BM, Stella L, Knudsen BR, Desideri A. Evidences of a natively unfolded state for the human topoisomerase IB N-terminal domain. Amino Acids 2010; 41:945-53. [PMID: 21046176 DOI: 10.1007/s00726-010-0794-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 10/20/2010] [Indexed: 09/29/2022]
Abstract
The N-terminal domain of human topoisomerase IB has been expressed, purified and characterized by spectroscopic techniques. CD spectra as a function of concentration and pH indicate that the domain does not possess any defined secondary structure. The protein is probably in a natively unfolded state since its denaturation curve is indicative of a non-cooperative transition. Evidence of a partially folded structure comes from the fluorescence spectrum of ANS, whose intensity increases in presence of the domain. Indication of a partial structural arrangement of the domain comes also from the endogenous fluorescence of tryptophans that is centred at 350 nm in the native and shifts to 354 nm in the fully denaturated protein. Interestingly despite the poor structural degree, as also confirmed by a predictive approach, the domain efficiently binds DNA, suggesting that the absence of a defined 3D structure has a functional meaning that permits the domain to be available for the interaction with different molecular partners.
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Affiliation(s)
- Oscar Vassallo
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica, 00133, Rome, Italy
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25
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Balestrazzi A, Locato V, Bottone MG, De Gara L, Biggiogera M, Pellicciari C, Botti S, Di Gesù D, Donà M, Carbonera D. Response to UV-C radiation in topo I-deficient carrot cells with low ascorbate levels. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:575-85. [PMID: 19917599 DOI: 10.1093/jxb/erp323] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In animal cells, recent studies have emphasized the role played by DNA topoisomerase I (topo I) both as a cofactor of DNA repair complexes and/or as a damage sensor. All these functions are still unexplored in plant cells, where information concerning the relationships between DNA damage, PCD induction, and topo I are also limited. The main goal of this study was to investigate the possible responses activated in topo I-depleted plant cells under oxidative stress conditions which induce DNA damage. The carrot (Daucus carota L.) AT1-beta/22 cell line analysed in this study (characterized by an antisense-mediated reduction of top1beta gene expression of approximately 46% in association with a low ascorbate content) was more sensitive to UV-C radiation than the control line, showing consistent cell death and high levels of 8-oxo-dG accumulation. The topo I-depleted cells were also highly susceptible to the cross-linking agent mitomycin C. The death response was associated with a lack of oxidative burst and there were no changes in ascorbate metabolism in response to UV-C treatment. Electron and fluorescence microscopy suggested the presence of three forms of cell death in the UV-C-treated AT1-beta/22 population: necrosis, apoptotic-like PCD, and autophagy. Taken together, the data reported here support a reduced DNA repair capability in carrot topo I-deficient cells while the putative relationship between topo I-depletion and ascorbate impairment is also discussed.
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Affiliation(s)
- A Balestrazzi
- Department of Genetics and Microbiology, University of Pavia, Via Ferrata 1, Pavia, Italy
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26
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Olorunniji FJ, Stark WM. The catalytic residues of Tn3 resolvase. Nucleic Acids Res 2009; 37:7590-602. [PMID: 19789272 PMCID: PMC2794168 DOI: 10.1093/nar/gkp797] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 09/08/2009] [Accepted: 09/09/2009] [Indexed: 11/16/2022] Open
Abstract
To characterize the residues that participate in the catalysis of DNA cleavage and rejoining by the site-specific recombinase Tn3 resolvase, we mutated conserved polar or charged residues in the catalytic domain of an activated resolvase variant. We analysed the effects of mutations at 14 residues on proficiency in binding to the recombination site ('site I'), formation of a synaptic complex between two site Is, DNA cleavage and recombination. Mutations of Y6, R8, S10, D36, R68 and R71 resulted in greatly reduced cleavage and recombination activity, suggesting crucial roles of these six residues in catalysis, whereas mutations of the other residues had less dramatic effects. No mutations strongly inhibited binding of resolvase to site I, but several caused conspicuous changes in the yield or stability of the synapse of two site Is observed by non-denaturing gel electrophoresis. The involvement of some residues in both synapsis and catalysis suggests that they contribute to a regulatory mechanism, in which engagement of catalytic residues with the substrate is coupled to correct assembly of the synapse.
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Affiliation(s)
| | - W. Marshall Stark
- Faculty of Biomedical and Life Sciences, University of Glasgow, Bower Building, Glasgow G12 8QQ, Scotland, UK
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27
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Maltseva DV, Baykov AA, Jeltsch A, Gromova ES. Impact of 7,8-dihydro-8-oxoguanine on methylation of the CpG site by Dnmt3a. Biochemistry 2009; 48:1361-8. [PMID: 19161295 DOI: 10.1021/bi801947f] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
7,8-Dihydro-8-oxoguanine (8-oxoG) is a ubiquitous oxidative DNA lesion resulting from injury to DNA via reactive oxygen species. 8-oxoG lesions may play a role in the formation of aberrant DNA methylation patterns during carcinogenesis. In this study, we assessed the effects of 8-oxoG on methylation and complex formation of nine 30-mer oligodeoxynucleotide duplexes by the catalytic domain of murine Dnmt3a DNA methyltransferase (Dnmt3a-CD). The effects of 8-oxoG on the methylation rate of hemimethylated duplexes varied from a 25-fold decrease to a 1.8-fold increase, depending on the position of the lesion relative to the Dnmt3a-CD recognition site (CpG) and target cytosine (C). The most significant effect was observed when 8-oxoG replaced guanine within the recognition site immediately downstream of the target cytosine. Fluorescence polarization experiments with fluorescein-labeled duplexes revealed that two molecules of Dnmt3a-CD bind per duplex, generating sigmoid binding curves. Duplexes exhibiting the highest apparent binding cooperativity formed the least stable 1:2 complexes with Dnmt3a-CD and were methylated at the lowest rate. Kinetic analyses disclosed the formation of very stable nonproductive enzyme-substrate complexes with hemimethylated duplexes that act as suicide substrates of Dnmt3a-CD. The presence of 8-oxoG within the CpG site downstream of the target cytosine markedly diminished productive versus nonproductive binding. We propose that 8-oxoG located adjacent to the target cytosine interferes with methylation by weakening the affinity of DNA for Dnmt3a-CD, thereby favoring a nonproductive binding mode.
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Affiliation(s)
- Diana V Maltseva
- Chemistry Department and A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119991, Russia
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28
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Rad50 is dispensable for the maintenance and viability of postmitotic tissues. Mol Cell Biol 2008; 29:483-92. [PMID: 19001091 DOI: 10.1128/mcb.01525-08] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The majority of spontaneous chromosome breakage occurs during the process of DNA replication. Homologous recombination is the primary mechanism of repair of such damage, which probably accounts for the fact that it is essential for genome integrity and viability in mammalian cells. The Mre11 complex plays diverse roles in the maintenance of genomic integrity, influencing homologous recombination, checkpoint activation, and telomere maintenance. The complex is essential for cellular viability, but given its myriad influences on genomic integrity, the mechanistic basis for the nonviability of Mre11 complex-deficient cells has not been defined. In this study we generated mice carrying a conditional allele of Rad50 and examined the effects of Rad50 deficiency in proliferative and nonproliferative settings. Depletion of Rad50 in cultured cells caused extensive DNA damage and death within 3 to 5 days of Rad50 deletion. This was not associated with gross telomere dysfunction, suggesting that the telomeric functions of the Mre11 complex are not required for viability. Rad50 was also dispensable for the viability of quiescent liver and postmitotic Purkinje cells of the cerebellum. These findings support the idea that the essential functions of the Mre11 complex are associated with DNA replication and further suggest that homologous recombination is not essential in nondividing cells.
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29
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Role of a tryptophan anchor in human topoisomerase I structure, function and inhibition. Biochem J 2008; 411:523-30. [PMID: 18215123 DOI: 10.1042/bj20071436] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Human Top1 (topoisomerase I) relaxes supercoiled DNA during cell division and transcription. Top1 is composed of 765 amino acids and contains an unstructured N-terminal domain of 200 amino acids, and a structured functional domain of 565 amino acids that binds and relaxes supercoiled DNA. In the present study we examined the region spanning the junction of the N-terminal domain and functional domain (junction region). Analysis of several published Top1 structures revealed that three tryptophan residues formed a network of aromatic stacking interactions and electrostatic interactions that anchored the N-terminus of the functional domain to sub-domains containing the nose cone and active site. Mutation of the three tryptophan residues (Trp(203)/Trp(205)/Trp(206)) to an alanine residue, either individually or together, in silico revealed that the individual tryptophan residue's contribution to the tryptophan 'anchor' was additive. When the three tryptophan residues were mutated to alanine in vitro, the resulting mutant Top1 differed from wild-type Top1 in that it lacked processivity, exhibited resistance to camptothecin and was inactivated by urea. The results indicated that the tryptophan anchor stabilized the N-terminus of the functional domain and prevented the loss of Top1 structure and function.
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Abstract
The inhibition of DNA topoisomerase I (Top1) has proven to be a successful approach in the design of anticancer agents. However, despite the clinical successes of the camptothecin derivatives, a significant need for less toxic and more chemically stable Top1 inhibitors still persists. Here, we describe one of the most frequently used protocols to identify novel Top1 inhibitors. These methods use uniquely 3'-radiolabeled DNA substrates and denaturing polyacrylamide gel electrophoresis to provide evidence for the Top1-mediated DNA cleaving activity of potential Top1 inhibitors. These assays allow comparison of the effectiveness of different drugs in stabilizing the Top1-DNA intermediate or cleavage (cleavable) complex. A variation on these assays is also presented, which provides a suitable system for determining whether the inhibitor blocks the forward cleavage or religation reactions by measuring the reversibility of the drug-induced Top1-DNA cleavage complexes. This entire protocol can be completed in approximately 2 d.
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Affiliation(s)
- Thomas S Dexheimer
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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31
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Ganguly A, Das B, Roy A, Sen N, Dasgupta SB, Mukhopadhayay S, Majumder HK. Betulinic Acid, a Catalytic Inhibitor of Topoisomerase I, Inhibits Reactive Oxygen Species Mediated Apoptotic Topoisomerase I DNA Cleavable Complex Formation in Prostate Cancer Cells but Does Not Affect the Process of Cell Death. Cancer Res 2007; 67:11848-58. [DOI: 10.1158/0008-5472.can-07-1615] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Katyal S, El-Khamisy SF, Russell HR, Li Y, Ju L, Caldecott KW, McKinnon PJ. TDP1 facilitates chromosomal single-strand break repair in neurons and is neuroprotective in vivo. EMBO J 2007; 26:4720-31. [PMID: 17914460 PMCID: PMC2080805 DOI: 10.1038/sj.emboj.7601869] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Accepted: 09/05/2007] [Indexed: 11/08/2022] Open
Abstract
Defective Tyrosyl-DNA phosphodiesterase 1 (TDP1) can cause spinocerebellar ataxia with axonal neuropathy (SCAN1), a neurodegenerative syndrome associated with marked cerebellar atrophy and peripheral neuropathy. Although SCAN1 lymphoblastoid cells show pronounced defects in the repair of chromosomal single-strand breaks (SSBs), it is unknown if this DNA repair activity is important for neurons or for preventing neurodegeneration. Therefore, we generated Tdp1-/- mice to assess the role of Tdp1 in the nervous system. Using both in vitro and in vivo assays, we found that cerebellar neurons or primary astrocytes derived from Tdp1-/- mice display an inability to rapidly repair DNA SSBs associated with Top1-DNA complexes or oxidative damage. Moreover, loss of Tdp1 resulted in age-dependent and progressive cerebellar atrophy. Tdp1-/- mice treated with topotecan, a drug that increases levels of Top1-DNA complexes, also demonstrated significant loss of intestinal and hematopoietic progenitor cells. These data indicate that TDP1 is required for neural homeostasis, and reveal a widespread requisite for TDP1 function in response to acutely elevated levels of Top1-associated DNA strand breaks.
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Affiliation(s)
- Sachin Katyal
- Department Genetics and Tumor Cell Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Sherif F El-Khamisy
- Genome Damage and Stability Center, University of Sussex, Falmer, Brighton, UK
- Biochemistry Department, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
| | - Helen R Russell
- Department Genetics and Tumor Cell Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Yang Li
- Department Genetics and Tumor Cell Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Limei Ju
- Genome Damage and Stability Center, University of Sussex, Falmer, Brighton, UK
| | - Keith W Caldecott
- Genome Damage and Stability Center, University of Sussex, Falmer, Brighton, UK
- Genome Damage and Stability Center, University of Sussex, Falmer, Brighton BN1 9RQ, UK. Tel.: +44 1323 877519; Fax: +44 1323 678121; E-mail:
| | - Peter J McKinnon
- Department Genetics and Tumor Cell Biology, St Jude Children's Research Hospital, Memphis, TN, USA
- Department Genetics and Tumor Cell Biology, St Jude Children's Research Hospital, 332 North Lauderdale, Memphis, TN 38105, USA. Tel.: +1 901 495 2700; Fax: +1 901 526 2907; E-mail:
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El-Khamisy SF, Hartsuiker E, Caldecott KW. TDP1 facilitates repair of ionizing radiation-induced DNA single-strand breaks. DNA Repair (Amst) 2007; 6:1485-95. [PMID: 17600775 DOI: 10.1016/j.dnarep.2007.04.015] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 04/20/2007] [Accepted: 04/23/2007] [Indexed: 01/25/2023]
Abstract
Tyrosyl DNA phosphodiesterase-1 (TDP1) is the gene product mutated in spinocerebellar ataxia with axonal neuropathy1 (SCAN1). SCAN1 is a hereditary ataxia that lacks extra-neurological phenotype, pointing to a critical role for TDP1 in the nervous system. Recently, we showed that TDP1 is associated with the DNA single-strand break (SSBR) repair machinery through an interaction with DNA ligase 3alpha (Lig3alpha) and that SCAN1 cells are defective in the repair of chromosomal DNA single-strand breaks (SSBs) arising from abortive Topoisomerase 1 (Top1)-DNA intermediates. Here we demonstrate that TDP1 is also required for the repair of SSBs induced by ionizing radiation (IR), though not measurably for IR-induced DNA double-strand breaks (DSBs). In addition, we provide evidence that abortive Top1 cleavage complexes are processed by the proteasome prior to the action of TDP1 in vivo, and we exploit this observation to show that the SSBR defect in SCAN1 following IR reflects, in part at least, the presence of IR-induced protein-DNA cross-links. Finally we show that TDP1 activity at abortive Top1-SSBs is stimulated by XRCC1/Lig3alpha in vitro. These data expand the type of SSBs processed by TDP1 to include those induced by ionizing radiation, and raise the possibility that TDP1 inhibitors may improve radiotherapy.
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Affiliation(s)
- Sherif F El-Khamisy
- Genome Damage and Stability Centre, University of Sussex, Science Park Road, Falmer, Brighton, UK.
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Abstract
Defects in cellular DNA repair processes have been linked to genome instability, heritable cancers, and premature aging syndromes. Yet defects in some repair processes manifest themselves primarily in neuronal tissues. This review focuses on studies defining the molecular defects associated with several human neurological disorders, particularly ataxia with oculomotor apraxia 1 (AOA1) and spinocerebellar ataxia with axonal neuropathy 1 (SCAN1). A picture is emerging to suggest that brain cells, due to their nonproliferative nature, may be particularly prone to the progressive accumulation of unrepaired DNA lesions.
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Affiliation(s)
- Ulrich Rass
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK
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35
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Mielke C, Kalfalah FM, Christensen MO, Boege F. Rapid and prolonged stalling of human DNA topoisomerase I in UVA-irradiated genomic areas. DNA Repair (Amst) 2007; 6:1757-63. [PMID: 17765665 DOI: 10.1016/j.dnarep.2007.06.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 06/22/2007] [Accepted: 06/25/2007] [Indexed: 12/31/2022]
Abstract
DNA topoisomerase I appears to be involved in DNA damage and repair in a complex manner. The enzyme is required for DNA maintenance and repair, but it may also damage DNA through its covalently DNA-bound, catalytic intermediate. The latter mechanism plays a role in tumor cell killing by camptothecins, but seems also involved in oxidative cell killing and certain stages of apoptosis. Stalling and/or suicidal DNA cleavage of topoisomerase I adjacent to nicks and modified DNA bases has been demonstrated in vitro. Here, we investigate the enzyme's interactions with UVA-induced DNA lesions inside living cells. We irradiated cells expressing GFP-tagged topoisomerase I with an UVA laser focused through a confocal microscope at confined areas of the nuclei. At irradiated sites, topoisomerase I accumulated within seconds, and accumulation lasted for more than 90 min. This effect was apparently due to reduced mobility, although the enzyme was not immobilized at the irradiated nuclear sites. Similar observations were made with mutant versions of topoisomerase I lacking the active site tyrosine or the N-terminal domain, but not with the N-terminal domain alone. Thus, accumulation of topoisomerase I at UVA-modified DNA sites is most likely due to non-covalent binding to damaged DNA, and not suicidal cleavage of such lesions. The rapid onset of accumulation suggests that topoisomerase I functions in this context as a component of DNA damage recognition and/or a cofactor of fast DNA-repair processes. However, the prolonged duration of accumulation suggests that it is also involved in more long-termed processes.
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Affiliation(s)
- Christian Mielke
- Institute of Clinical Chemistry and Laboratory Diagnostics, Heinrich-Heine-University, Medical School, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
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36
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Christmann-Franck S, Fermandjian S, Mirambeau G, Der Garabedian PA. Molecular modelling studies on the interactions of human DNA topoisomerase IB with pyridoxal-compounds. Biochimie 2007; 89:468-73. [PMID: 17116355 DOI: 10.1016/j.biochi.2006.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Accepted: 10/10/2006] [Indexed: 11/27/2022]
Abstract
Candida guilliermondii and human DNA topoisomerases I are inhibited by PL (pyridoxal), PLP (pyridoxal 5'-phosphate) and PLP-AMP (pyridoxal 5'-diphospho-5'-adenosine) (PL<PLP<PLP-AMP). We have recently shown that PLP acted as a competitive inhibitor of C. guilliermondii topoisomerase I, impeding the formation of the cleavable complex from a selective binding to an active site lysine. The targeted lysine in C. guilliermondii topoisomerase I occupies a position equivalent to that of lysine 532 (K(532)) in human topoisomerase I. K(532) acts as a general acid catalyst and is essential for the enzyme activity. This observation has suggested that, in the cell, PLP could down-regulate topoisomerases IB. We have proposed that PLP could be used as a new lead for anticancer drugs trapping the active site lysine (K(532)) and also as a tool to explore the enzyme dynamics required for catalysis. Now we explore the effects of PL, PLP and PLP-AMP on topoisomerases by a molecular modelling approach using the crystal structure of the human topoisomerase I active site and the conformation of K(39)-PLP moiety in Bacillus subtilis alanine racemase as templates. In the modified topoisomerase I several reactive atoms of the K(532)-PLP moiety are at close distance of the catalytic residues R(488), R(590), H(632) and Y(723,) suggesting that PLP develops disturbing interactions with these important residues. These interactions and the corresponding induced fit in the active site conformation are compared with the ones occurring with PL and PLP-AMP. The results could be useful in the search of topoisomerase I inhibitors related to the pyridoxal family.
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Affiliation(s)
- Serge Christmann-Franck
- Département de Biologie et Pharmacologie Structurales, CNRS UMR 8113, Institut Gustave Roussy et ENS Cachan, 61 Avenue du Président Wilson, 94235 Cachan Cedex, France
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37
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Montaudon D, Palle K, Rivory LP, Robert J, Douat-Casassus C, Quideau S, Bjornsti MA, Pourquier P. Inhibition of topoisomerase I cleavage activity by thiol-reactive compounds: importance of vicinal cysteines 504 and 505. J Biol Chem 2007; 282:14403-12. [PMID: 17355975 DOI: 10.1074/jbc.m611673200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
DNA topoisomerase I (Top1) is a nuclear enzyme that plays a crucial role in the removal of DNA supercoiling associated with replication and transcription. It is also the target of the anticancer agent, camptothecin (CPT). Top1 contains eight cysteines, including two vicinal residues (504 and 505), which are highly conserved across species. In this study, we show that thiol-reactive compounds such as N-ethylmaleimide and phenylarsine oxide can impair Top1 catalytic activity. We demonstrate that in contrast to CPT, which inhibits Top1-catalyzed religation, thiolation of Top1 inhibited the DNA cleavage step of the reaction. This inhibition was more pronounced when Top1 was preincubated with the thiol-reactive compound and could be reversed in the presence of dithiothreitol. We also established that phenylarsine oxide-mediated inhibition of Top1 cleavage involved the two vicinal cysteines 504 and 505, as this effect was suppressed when cysteines were mutated to alanines. Interestingly, mutation of Cys-505 also altered Top1 sensitivity to CPT, even in the context of the double Cys-504 to Cys-505 mutant, which relaxed supercoiled DNA with a comparable efficiency to that of wild-type Top1. This indicates that cysteine 505, which is located in the lower Lip domain of human Top1, is critical for optimal poisoning of the enzyme by CPT and its analogs. Altogether, our results suggest that conserved vicinal cysteines 504 and 505 of human Top1 play a critical role in enzyme catalytic activity and are the target of thiol-reactive compounds, which may be developed as efficient Top1 catalytic inhibitors.
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Affiliation(s)
- Danièle Montaudon
- Groupe de Pharmacologie Moléculaire INSERM E347 and Institut Bergonié, 229 Cours de l'Argonne, Université Victor Segalen Bordeaux II, 146 Rue Léo Saignat, 33076 Bordeaux Cedex, France
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38
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el-Khamisy SF, Caldecott KW. DNA single-strand break repair and spinocerebellar ataxia with axonal neuropathy-1. Neuroscience 2006; 145:1260-6. [PMID: 17045754 DOI: 10.1016/j.neuroscience.2006.08.048] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Revised: 08/01/2006] [Accepted: 08/07/2006] [Indexed: 10/24/2022]
Abstract
DNA single-strand breaks (SSBs) are the commonest DNA lesions arising spontaneously in cells, and if not repaired may block transcription or may be converted into potentially lethal/clastogenic DNA double-strand breaks (DSBs). Recently, evidence has emerged that defects in the rapid repair of SSBs preferentially impact the nervous system. In particular, spinocerebellar ataxia with axonal neuropathy (SCAN1) is a human disease that is associated with mutation of TDP1 (tyrosyl DNA phosphodiesterase 1) protein and with a defect in repairing certain types of SSBs. Although SCAN1 is a rare neurodegenerative disorder, understanding the molecular basis of this disease will lead to better understanding of neurodegenerative processes. Here we review recent progress in our understanding of TDP1, single-strand break repair (SSBR), and neurodegenerative disease.
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Affiliation(s)
- S F el-Khamisy
- Genome Damage and Stability Centre, University of Sussex, Science Park Road, Falmer, Brighton BN1 9RQ, UK
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39
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Jena NR, Mishra PC. A theoretical study of some new analogues of the anti-cancer drug camptothecin. J Mol Model 2006; 13:267-74. [PMID: 17024403 DOI: 10.1007/s00894-006-0157-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2006] [Accepted: 09/19/2006] [Indexed: 10/24/2022]
Abstract
The enzyme topoisomerase I (topo I), which is essential for cell replication, transiently causes a DNA single strand break and makes a complex with it. The anti-cancer agent camptothecin (CPT) binds to the topo I-DNA complex and stabilizes it, preventing resealing of the broken DNA strand and cell growth. Considering the structural factors of CPT that are believed to be involved in stabilizing the topo I-DNA complex via hydrogen bonding and stacking interactions, designs of two new analogues of CPT (topo I inhibitors) have been suggested. The molecular geometries of CPT, two of its analogues and certain other related molecules included in the study were fully optimized in both gas phase and aqueous media at the B3LYP/6-311++G(d,p) level of density functional theory. Solvation effects of aqueous media were treated using the polarizable continuum model (PCM). Net CHelpG charges and surface molecular electrostatic potentials (MEP) near the atomic sites of the molecules were studied. Structural analogy and surface MEP values suggests that the two new CPT analogues studied here would be potent topoisomerase I inhibitors.
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Affiliation(s)
- Nihar R Jena
- Department of Physics, Banaras Hindu University, Varanasi, 221005, India
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40
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Abstract
Nuclear DNA topoisomerase I (TOP1) is an essential human enzyme. It is the only known target of the alkaloid camptothecin, from which the potent anticancer agents irinotecan and topotecan are derived. As camptothecins bind at the interface of the TOP1-DNA complex, they represent a paradigm for interfacial inhibitors that reversibly trap macromolecular complexes. Several camptothecin and non-camptothecin derivatives are being developed to further increase anti-tumour activity and reduce side effects. The mechanisms and molecular determinants of tumour response to TOP1 inhibitors are reviewed, and rational combinations of TOP1 inhibitors with other drugs are considered based on current knowledge of repair and checkpoint pathways that are associated with TOP1-mediated DNA damage.
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Affiliation(s)
- Yves Pommier
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, 20892-4255, USA.
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41
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Miao ZH, Rao VA, Agama K, Antony S, Kohn KW, Pommier Y. 4-nitroquinoline-1-oxide induces the formation of cellular topoisomerase I-DNA cleavage complexes. Cancer Res 2006; 66:6540-5. [PMID: 16818625 DOI: 10.1158/0008-5472.can-05-4471] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RecQ helicase BLM-deficient cells are characteristically hypersensitive to 4-nitroquinoline-1-oxide (4NQO). We recently reported that isogenic BLM-deficient cells (PNSG13) are more sensitive than BLM-complemented cells (PNSF5) to camptothecin, which specifically traps topoisomerase I cleavage complexes (Top1cc). We now report that PNSG13 are also 3.5-fold more sensitive to 4NQO compared with PNSF5 and that 4NQO induces higher levels of Top1cc and reduced histone gamma-H2AX in PSNG13 than in PNSF5. Similarly, 4NQO induces more Top1cc in primary fibroblasts from a patient with Bloom syndrome than in normal human fibroblasts. 4NQO also induces Top1cc in colon cancer HCT116 and HT29 cells in a time- and concentration-dependent fashion. Of note, distinct from camptothecin, the Top1cc produced by 4NQO accumulate progressively after 4NQO addition and persist following 4NQO removal. The Top1cc induced by 4NQO are detectable by alkaline elution. To examine the functional relevance of the Top1cc induced by 4NQO, we used two stable topoisomerase I small interfering RNA (siRNA) cell lines derived from HCT116 and MCF7 cells. Both topoisomerase I siRNA cell lines are resistant to 4NQO, indicating that Top1cc contribute to the cellular activity of 4NQO. Collectively, these data show that 4NQO is an effective inducer of cellular Top1cc. Because 4NQO does not directly trap Top1cc in biochemical assays, we propose that active metabolites of 4NQO trap Top1cc by forming DNA adducts. Induction of Top1cc and histone gamma-H2AX by 4NQO may contribute to the cellular effects of 4NQO, including its selective activity toward RecQ helicase BLM-deficient cells.
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Affiliation(s)
- Ze-Hong Miao
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute/NIH, Bethesda, MD 20892, USA
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42
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El-Khamisy SF, Caldecott KW. TDP1-dependent DNA single-strand break repair and neurodegeneration. Mutagenesis 2006; 21:219-24. [PMID: 16775218 DOI: 10.1093/mutage/gel024] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
DNA single-strand breaks (SSBs) are the commonest DNA lesions that arise spontaneously in living cells. Cells employ efficient processes for the rapid repair of these breaks and defects in these processes appear to preferentially impact on the nervous system, causing human ataxia. Spinocerebellar ataxia with axonal neuropathy (SCAN1) is a human disease that is associated with a defect in repairing certain types of SSBs. Although it is a rare neurodegenerative disease, understanding the molecular basis of SCAN1 will lead to better understanding of the mechanisms that underpin not only neurodegeneration but also cancer.
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Affiliation(s)
- Sherif F El-Khamisy
- Genome Damage and Stability Centre, University of Sussex Falmer, Brighton BN1 9RQ, UK.
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43
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Jena N, Mishra P. Addition and hydrogen abstraction reactions of an OH radical with 8-oxoguanine. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.02.096] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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44
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Kim JE, Hyun JW, Hayakawa H, Choi S, Choi J, Chung MH. Exogenous 8-oxo-dG is not utilized for nucleotide synthesis but enhances the accumulation of 8-oxo-Gua in DNA through error-prone DNA synthesis. Mutat Res 2006; 596:128-36. [PMID: 16472828 DOI: 10.1016/j.mrfmmm.2005.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Revised: 12/14/2005] [Accepted: 12/22/2005] [Indexed: 11/20/2022]
Abstract
7,8-Dihydro-8-oxoguanine (8-oxo-Gua) and its nucleoside in cytosol are derived from the repair of oxidative DNA and the cleanup of oxidatively damaged DNA precursors, respectively. While the harmful effects of 8-oxo-Gua present in DNA have been studied extensively, few have reported its effects on cytosolic function. Our previous study showed that the addition of 8-oxo-dG to culture media caused an accumulation of 8-oxo-Gua in nuclear DNA in several leukemic cells including KG-1, which lack 8-oxoguanine glycosylase 1 (OGG1) activity due to mutational loss. However, the mechanism underlying 8-oxo-Gua level increases in DNA has not been addressed. In this study, we elucidated the metabolic fate of 8-oxo-Gua-containing nucleotide and the effect of exogenous 8-oxo-dG on DNA synthesis in KG-1 cells. We found that 8-oxo-dGMP was rapidly dephosphorylated to 8-oxo-dG rather than phosphorylated to 8-oxo-dGDP, thus indicating that 8-oxo-Gua-containing molecule is not used as a substrate for DNA synthesis in KG-1 cells. In fact, radiolabeled 8-oxo-dG was incubated but radioactivity was not detected in nuclear DNA of KG-1 cells, showing that 8-oxo-dG is not directly incorporated into DNA. Interestingly, the activity of DNA polymerase beta, which synthesize DNA with low fidelity increased in KG-1 cells treated with 8-oxo-dG, whereas the expression of DNA polymerase alpha decreased. In addition, the accumulation of 8-oxo-Gua in KG-1 DNA was completely inhibited by a specific inhibitor of DNA polymerase beta. Thus, our findings address that the insertion of 8-oxo-dG into KG-1 DNA is not due to the direct incorporation of exogenous 8-oxo-dG, but rather to the inaccurate incorporation of endogenous 8-oxo-dGTP by DNA polymerase beta. It further suggests that 8-oxo-dG in the cytosol may function as an active molecule itself and perturb the well-defined DNA synthesis.
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Affiliation(s)
- Ja-Eun Kim
- Department of Pharmacology, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-799, Republic of Korea
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45
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Pommier Y, Barcelo J, Rao VA, Sordet O, Jobson AG, Thibaut L, Miao Z, Seiler J, Zhang H, Marchand C, Agama K, Redon C. Repair of topoisomerase I-mediated DNA damage. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2006; 81:179-229. [PMID: 16891172 PMCID: PMC2576451 DOI: 10.1016/s0079-6603(06)81005-6] [Citation(s) in RCA: 225] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Topoisomerase I (Top1) is an abundant and essential enzyme. Top1 is the selective target of camptothecins, which are effective anticancer agents. Top1-DNA cleavage complexes can also be trapped by various endogenous and exogenous DNA lesions including mismatches, abasic sites and carcinogenic adducts. Tyrosyl-DNA phosphodiesterase (Tdp1) is one of the repair enzymes for Top1-DNA covalent complexes. Tdp1 forms a multiprotein complex that includes poly(ADP) ribose polymerase (PARP). PARP-deficient cells are hypersensitive to camptothecins and functionally deficient for Tdp1. We will review recent developments in several pathways involved in the repair of Top1 cleavage complexes and the role of Chk1 and Chk2 checkpoint kinases in the cellular responses to Top1 inhibitors. The genes conferring camptothecin hypersensitivity are compiled for humans, budding yeast and fission yeast.
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Affiliation(s)
- Yves Pommier
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
| | - Juana Barcelo
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
| | - V. Ashutosh Rao
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
| | - Olivier Sordet
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
| | - Andrew G. Jobson
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
| | - Laurent Thibaut
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
| | - Zheyong Miao
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
| | - Jennifer Seiler
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
| | - Hongliang Zhang
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
| | - Christophe Marchand
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
| | - Keli Agama
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
| | - Christophe Redon
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, DHHS
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46
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Raymond AC, Staker BL, Burgin AB. Substrate Specificity of Tyrosyl-DNA Phosphodiesterase I (Tdp1). J Biol Chem 2005; 280:22029-35. [PMID: 15811850 DOI: 10.1074/jbc.m502148200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tyrosyl-DNA phosphodiesterase I (Tdp1) hydrolyzes 3'-phosphotyrosyl bonds to generate 3'-phosphate DNA and tyrosine in vitro. Tdp1 is involved in the repair of DNA lesions created by topoisomerase I, although the in vivo substrate is not known. Here we study the kinetic and binding properties of human Tdp1 (hTdp1) to identify appropriate 3'-phosphotyrosyl DNA substrates. Genetic studies argue that Tdp1 is involved in double and single strand break repair pathways; however, x-ray crystal structures suggest that Tdp1 can only bind single strand DNA. Separate kinetic and binding experiments show that hTdp1 has a preference for single-stranded and blunt-ended duplex substrates over nicked and tailed duplex substrate conformations. Based on these results, we present a new model to explain Tdp1/DNA binding properties. These results suggest that Tdp1 only acts upon double strand breaks in vivo, and the roles of Tdp1 in yeast and mammalian cells are discussed.
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Affiliation(s)
- Amy C Raymond
- deCODE biostructures, 7869 NE Day Road West, Bainbridge Island, WA 98110, USA
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47
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Staker BL, Feese MD, Cushman M, Pommier Y, Zembower D, Stewart L, Burgin AB. Structures of three classes of anticancer agents bound to the human topoisomerase I-DNA covalent complex. J Med Chem 2005; 48:2336-45. [PMID: 15801827 DOI: 10.1021/jm049146p] [Citation(s) in RCA: 369] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human topoisomerase I (top1) is the molecular target of a diverse set of anticancer compounds, including the camptothecins, indolocarbazoles, and indenoisoquinolines. These compounds bind to a transient top1-DNA covalent complex and inhibit the resealing of a single-strand nick that the enzyme creates to relieve superhelical tension in duplex DNA. (Hertzberg, R. P.; et al. Biochem. 1989, 28, 4629-4638. Hsiang, Y. H.; et al. J. Biol. Chem 1985, 260, 14873-14878. Champoux, J. J. Annu. Rev. Biochem. 2001, 70, 369-413. Stewart, L.; et al. Science 1998, 729, 1534-1541.) We report the X-ray crystal structures of the human top1-DNA complex bound with camptothecin and representative members of the indenoisoquinoline and indolocarbazole classes of top1 poisons. The planar nature of all three structurally diverse classes allows them to intercalate between DNA base pairs at the site of single-strand cleavage. All three classes of compounds have a free electron pair near Arg364, a residue that if mutated confers resistance to all three classes of drugs. The common intercalative binding mode is augmented by unexpected chemotype-specific contacts with amino acid residues Asn352 and Glu356, which adopt alternative side-chain conformations to accommodate the bound compounds. These new X-ray structures explain how very different molecules can stabilize top1-DNA covalent complexes and will aid the rational design of completely novel structural classes of anticancer drugs.
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Affiliation(s)
- Bart L Staker
- deCODE BioStructures, 7869 NE Day Road West, Bainbridge Island, Washington 98110, USA
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48
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The calculated base pairing energy of 8-oxoguanine in the syn–anti conformation with cytosine, thymine, adenine and guanine. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.theochem.2004.12.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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49
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Leppard JB, Champoux JJ. Human DNA topoisomerase I: relaxation, roles, and damage control. Chromosoma 2005; 114:75-85. [PMID: 15830206 DOI: 10.1007/s00412-005-0345-5] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 03/29/2005] [Accepted: 03/30/2005] [Indexed: 11/28/2022]
Abstract
Human DNA topoisomerase I is an essential enzyme involved in resolving the torsional stress associated with DNA replication, transcription, and chromatin condensation. The catalytic cycle of the enzyme consists of DNA cleavage to form a covalent enzyme-DNA intermediate, DNA relaxation, and finally, re-ligation of the phosphate backbone to restore the continuity of the DNA. Structure/function studies have elucidated a flexible enzyme that relaxes DNA through coordinated, controlled movements of distinct enzyme domains. The cellular roles of topoisomerase I are apparent throughout the nucleus, but the concentration of processes acting on ribosomal DNA results in topoisomerase I accumulation in the nucleolus. Although the activity of topoisomerase I is required in these processes, the enzyme can also have a deleterious effect on cells. In the event that the final re-ligation step of the reaction cycle is prevented, the covalent topoisomerase I-DNA intermediate becomes a toxic DNA lesion that must be repaired. The complexities of the relaxation reaction, the cellular roles, and the pathways that must exist to repair topoisomerase I-mediated DNA damage highlight the importance of continued study of this essential enzyme.
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Affiliation(s)
- John B Leppard
- Department of Microbiology, School of Medicine, University of Washington, P.O. Box 357242, 1959 N.E. Pacific St., Seattle, WA 98195-7242, USA
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50
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Colley WC, van der Merwe M, Vance JR, Burgin AB, Bjornsti MA. Substitution of Conserved Residues within the Active Site Alters the Cleavage Religation Equilibrium of DNA Topoisomerase I. J Biol Chem 2004; 279:54069-78. [PMID: 15489506 DOI: 10.1074/jbc.m409764200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Eukaryotic DNA topoisomerase I (Top1p) catalyzes the relaxation of supercoiled DNA and constitutes the cellular target of camptothecin (CPT). Mutation of conserved residues in close proximity to the active site tyrosine (Tyr(727) of yeast Top1p) alters the DNA cleavage religation equilibrium, inducing drug-independent cell lethality. Previous studies indicates that yeast Top1T722Ap and Top1N726Hp cytotoxicity results from elevated levels of covalent enzyme-DNA intermediates. Here we show that Top1T722Ap acts as a CPT mimetic by exhibiting reduced rates of DNA religation, whereas increased Top1N726Hp.DNA complexes result from elevated DNA binding and cleavage. We also report that the combination of the T722A and N726H mutations in a single protein potentiates the cytotoxic action of the enzyme beyond that induced by co-expression of the single mutants. Moreover, the addition of CPT to cells expressing the double top1T722A/N726H mutant did not enhance cell lethality. Thus, independent alterations in DNA cleavage and religation contribute to the lethal phenotype. The formation of distinct cytotoxic lesions was also evidenced by the different responses induced by low levels of these self-poisoning enzymes in isogenic strains defective for the Rad9 DNA damage checkpoint, processive DNA replication, or ubiquitin-mediated proteolysis. Substitution of Asn(726) with Phe or Tyr also produces self-poisoning enzymes, implicating stacking interactions in the increased kinetics of DNA cleavage by Top1N726Hp and Top1N726Fp. In contrast, replacing the amide side chain of Asn(726) with Gln renders Top1N726Qp resistant to CPT, suggesting that the orientation of the amide within the active site is critical for effective CPT binding.
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Affiliation(s)
- William C Colley
- Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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