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Gohil D, Sarker AH, Roy R. Base Excision Repair: Mechanisms and Impact in Biology, Disease, and Medicine. Int J Mol Sci 2023; 24:14186. [PMID: 37762489 PMCID: PMC10531636 DOI: 10.3390/ijms241814186] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/12/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Base excision repair (BER) corrects forms of oxidative, deamination, alkylation, and abasic single-base damage that appear to have minimal effects on the helix. Since its discovery in 1974, the field has grown in several facets: mechanisms, biology and physiology, understanding deficiencies and human disease, and using BER genes as potential inhibitory targets to develop therapeutics. Within its segregation of short nucleotide (SN-) and long patch (LP-), there are currently six known global mechanisms, with emerging work in transcription- and replication-associated BER. Knockouts (KOs) of BER genes in mouse models showed that single glycosylase knockout had minimal phenotypic impact, but the effects were clearly seen in double knockouts. However, KOs of downstream enzymes showed critical impact on the health and survival of mice. BER gene deficiency contributes to cancer, inflammation, aging, and neurodegenerative disorders. Medicinal targets are being developed for single or combinatorial therapies, but only PARP and APE1 have yet to reach the clinical stage.
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Affiliation(s)
- Dhara Gohil
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA;
| | - Altaf H. Sarker
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA;
| | - Rabindra Roy
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA;
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2
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Wallace SS. Molecular radiobiology and the origins of the base excision repair pathway: an historical perspective. Int J Radiat Biol 2021; 99:891-902. [DOI: 10.1080/09553002.2021.1908639] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Susan S. Wallace
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, USA
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3
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Rodriguez Y, Horton JK, Wilson SH. Histone H3 Lysine 56 Acetylation Enhances AP Endonuclease 1-Mediated Repair of AP Sites in Nucleosome Core Particles. Biochemistry 2019; 58:3646-3655. [PMID: 31407575 DOI: 10.1021/acs.biochem.9b00433] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Deciphering factors modulating DNA repair in chromatin is of great interest because nucleosomal positioning influences mutation rates. H3K56 acetylation (Ac) is implicated in chromatin landscape regulation, impacting genomic stability, yet the effect of H3K56Ac on DNA base excision repair (BER) remains unclear. We determined whether H3K56Ac plays a role in regulating AP site incision by AP endonuclease 1 (APE1), an early step in BER. Our in vitro studies of acetylated, well-positioned nucleosome core particles (H3K56Ac-601-NCPs) demonstrate APE1 strand incision is enhanced compared with that of unacetylated WT-601-NCPs. The high-mobility group box 1 protein enhances APE1 activity in WT-601-NCPs, but this effect is not observed in H3K56Ac-601-NCPs. Therefore, our results suggest APE1 activity on NCPs can be modulated by H3K56Ac.
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Affiliation(s)
- Yesenia Rodriguez
- Genome Integrity and Structural Biology Laboratory , National Institute of Environmental Health Sciences , Research Triangle Park , North Carolina 27709 , United States
| | - Julie K Horton
- Genome Integrity and Structural Biology Laboratory , National Institute of Environmental Health Sciences , Research Triangle Park , North Carolina 27709 , United States
| | - Samuel H Wilson
- Genome Integrity and Structural Biology Laboratory , National Institute of Environmental Health Sciences , Research Triangle Park , North Carolina 27709 , United States
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4
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Zakharenko AL, Lebedeva NA, Lavrik OI. DNA Repair Enzymes as Promising Targets in Oncotherapy. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2018. [DOI: 10.1134/s1068162017060140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Arjumand W, Asiaf A, Ahmad ST. Noncoding RNAs in DNA Damage Response: Opportunities for Cancer Therapeutics. Methods Mol Biol 2018; 1699:3-21. [PMID: 29086365 DOI: 10.1007/978-1-4939-7435-1_1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
DNA repair machinery preserves genomic integrity, which is frequently challenged through endogenous and exogenous toxic insults, and any sort of repair machinery malfunctioning ultimately manifests in the form of several types of terrible human diseases such as cancers (Hoeijmakers, Nature 411(6835): 366-374, 2001). Noncoding RNAs (ncRNAs) are crucial players of DNA repair machinery in a cell and play a vital role in maintaining genomic stability, which is essential for its survival and normal functioning thus preventing tumorigenesis. To preserve the integrity of the genome, cells initiate a specific cellular response, recognized as DNA damage response (DDR), which includes several distinct DNA repair pathways. These repair pathways permit normal cells to repair DNA damage or induce apoptosis and cell cycle arrest in case the damage is irreparable. Disruption of these pathways in cancer leads to an increase in genomic instability and mutagenesis. Recently, emerging evidence suggests that ncRNAs play a critical role in the regulation of DDR. There is an extensive crosstalk between ncRNAs and the canonical DDR signaling pathway. DDR-induced expression of ncRNAs can provide a regulatory mechanism to accurately control the expression of DNA damage responsive genes in a spatio-temporal manner. DNA damage alters expression of a variety of ncRNAs at multiple levels including transcriptional regulation, post-transcriptional regulation, and RNA degradation and vice versa, wherein ncRNAs can directly regulate cellular processes involved in DDR by altering expression of their targeting genes, with a particular emphasis on microRNAs (miRNAs) and long noncoding RNAs (lncRNAs). Relationship between the defects in the DDR and deregulation of related ncRNAs in human cancers is one of the established, which is growing stronger with the advent of high-throughput sequencing techniques such as next-generation sequencing. Understanding of the mechanisms that explain the association between ncRNAs and DDR/DNA repair pathways will definitely increase our understanding on human tumor biology and on different responses to diverse drugs. Different ncRNAs interact with distinct DDR components and are promising targets for improving the effects to overcome the resistance to conventional chemotherapeutic agents. In this chapter, we will focus the role of ncRNAs in the DNA damage, repair, and cancer.
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Affiliation(s)
- Wani Arjumand
- Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine, 2A32 HRIC, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N4N1, Canada
| | - Asia Asiaf
- Department of Biochemistry, Faculty of Science, University of Kashmir, Hazratbal Srinagar, J&K, 190006, India
| | - Shiekh Tanveer Ahmad
- Clarke H. Smith Brain Tumour Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine, 2A25 HRIC, University of Calgary, 3330 Hospital Drive, NW, Calgary, AB, T2N4N1, Canada.
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6
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Laev SS, Salakhutdinov NF, Lavrik OI. Inhibitors of nuclease and redox activity of apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1). Bioorg Med Chem 2017; 25:2531-2544. [PMID: 28161249 DOI: 10.1016/j.bmc.2017.01.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/16/2017] [Accepted: 01/18/2017] [Indexed: 01/15/2023]
Abstract
Human apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1) is a multifunctional protein which is essential in the base excision repair (BER) pathway of DNA lesions caused by oxidation and alkylation. This protein hydrolyzes DNA adjacent to the 5'-end of an apurinic/apyrimidinic (AP) site to produce a nick with a 3'-hydroxyl group and a 5'-deoxyribose phosphate moiety or activates the DNA-binding activity of certain transcription factors through its redox function. Studies have indicated a role for APE1/Ref-1 in the pathogenesis of cancer and in resistance to DNA-interactive drugs. Thus, this protein has potential as a target in cancer treatment. As a result, major efforts have been directed to identify small molecule inhibitors against APE1/Ref-1 activities. These agents have the potential to become anticancer drugs. The aim of this review is to present recent progress in studies of all published small molecule APE1/Ref-1 inhibitors. The structures and activities of APE1/Ref-1 inhibitors, that target both DNA repair and redox activities, are presented and discussed. To date, there is an urgent need for further development of the design and synthesis of APE1/Ref-1 inhibitors due to high importance of this protein target.
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Affiliation(s)
- Sergey S Laev
- Vorozhtsov Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 9, Novosibirsk 630090, Russian Federation.
| | - Nariman F Salakhutdinov
- Vorozhtsov Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 9, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russian Federation
| | - Olga I Lavrik
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russian Federation; Novosibirsk Institute of Chemical Biology and Fundamental Medicine, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 8, Novosibirsk 630090, Russian Federation
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7
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Ray D, Kidane D. Gut Microbiota Imbalance and Base Excision Repair Dynamics in Colon Cancer. J Cancer 2016; 7:1421-30. [PMID: 27471558 PMCID: PMC4964126 DOI: 10.7150/jca.15480] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 05/18/2016] [Indexed: 12/15/2022] Open
Abstract
Gut microbiota are required for host nutrition, energy balance, and regulating immune homeostasis, however, in some cases, this mutually beneficial relationship becomes twisted (dysbiosis), and the gut flora can incite pathological disorders including colon cancer. Microbial dysbiosis promotes the release of bacterial genotoxins, metabolites, and causes chronic inflammation, which promote oxidative DNA damage. Oxidized DNA base lesions are removed by base excision repair (BER), however, the role of this altered function of BER, as well as microbiota-mediated genomic instability and colon cancer development, is still poorly understood. In this review article, we will discuss how dysbiotic microbiota induce DNA damage, its impact on base excision repair capacity, the potential link of host BER gene polymorphism, and the risk of dysbiotic microbiota mediated genomic instability and colon cancer.
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Affiliation(s)
- Debolina Ray
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd. R1800, Austin, TX 78723, United States
| | - Dawit Kidane
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd. R1800, Austin, TX 78723, United States
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Canugovi C, Misiak M, Ferrarelli LK, Croteau DL, Bohr VA. The role of DNA repair in brain related disease pathology. DNA Repair (Amst) 2013; 12:578-87. [PMID: 23721970 DOI: 10.1016/j.dnarep.2013.04.010] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Oxidative DNA damage is implicated in brain aging, neurodegeneration and neurological diseases. Damage can be created by normal cellular metabolism, which accumulates with age, or by acute cellular stress conditions which create bursts of oxidative damage. Brain cells have a particularly high basal level of metabolic activity and use distinct oxidative damage repair mechanisms to remove oxidative damage from DNA and dNTP pools. Accumulation of this damage in the background of a functional DNA repair response is associated with normal aging, but defective repair in brain cells can contribute to neurological dysfunction. Emerging research strongly associates three common neurodegenerative conditions, Alzheimer's, Parkinson's and stroke, with defects in the ability to repair chronic or acute oxidative damage in neurons. This review explores the current knowledge of the role of oxidative damage repair in preserving brain function and highlights the emerging models and methods being used to advance our knowledge of the pathology of neurodegenerative disease.
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Affiliation(s)
- Chandrika Canugovi
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, Baltimore, MD 21224, USA
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9
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Cun Y, Zhang Q, Xiong C, Li M, Dai N, Zhang S, Wang D. Combined use of adenoviral vector Ad5/F35-mediated APE1 siRNA enhances the therapeutic efficacy of adenoviral-mediated p53 gene transfer in hepatoma cells in vitro and in vivo. Oncol Rep 2013; 29:2197-204. [PMID: 23563597 DOI: 10.3892/or.2013.2384] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 02/14/2013] [Indexed: 01/10/2023] Open
Abstract
Gene therapy has emerged as a novel therapeutic approach for the treatment of cancer. In order to establish a more effective therapeutic strategy against unresectable hepatocellular carcinoma (HCC), we evaluated, in the present study, the effects of combined treatment with adenoviral vector Ad5/F35-mediated APE1 siRNA (Ad5/F35-siAPE1) and adenoviral-mediated p53 gene transfer (Ad-p53) in hepatoma cells in vitro and in vivo. Infection of SMMC-7721 cells with Ad5/F35-siAPE1 resulted in a time- and dose-dependent decrease of APE1 protein, while Ad-p53 treatment led to a time- and dose-dependent increase of p53 protein expression. Ad5/F35-siAPE1 significantly enhanced the cytotoxic effect of SMMC-7721 cells to Ad-p53 in cell survival assays, associated with increased cell apoptosis. Moreover, administration of Ad5/F35-siAPE1 and Ad-p53 into nude mice resulted in tumor growth inhibition and apoptosis induction in SMMC-7721 xenografts compared to administration of either agent alone. These results suggest that combination of Ad5/F35-siAPE1 and Ad-p53 could be a promising gene therapeutic approach against human HCC.
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Affiliation(s)
- Yanping Cun
- Cancer Center, Daping Hospital and Research Institute of Surgery, Third Military Medical University, Chongqing 400042, PR China
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10
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Jonson I, Ougland R, Larsen E. DNA repair mechanisms in Huntington's disease. Mol Neurobiol 2013; 47:1093-102. [PMID: 23361256 DOI: 10.1007/s12035-013-8409-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/13/2013] [Indexed: 11/25/2022]
Abstract
The human genome is under continuous attack by a plethora of harmful agents. Without the development of several dedicated DNA repair pathways, the genome would have been destroyed and cell death, inevitable. However, while DNA repair enzymes generally maintain the integrity of the whole genome by properly repairing mutagenic and cytotoxic intermediates, there are cases in which the DNA repair machinery is implicated in causing disease rather than protecting against it. One case is the instability of gene-specific trinucleotides, the causative mutations of numerous disorders including Huntington's disease. The DNA repair proteins induce mutations that are different from the genome-wide mutations that arise in the absence of repair enzymes; they occur at definite loci, they occur in specific tissues during development, and they are age-dependent. These latter characteristics make pluripotent stem cells a suitable model system for triplet repeat expansion disorders. Pluripotent stem cells can be kept in culture for a prolonged period of time and can easily be differentiated into any tissue, e.g., cells along the neural lineage. Here, we review the role of DNA repair proteins in the process of triplet repeat instability in Huntington's disease and also the potential use of pluripotent stem cells to investigate neurodegenerative disorders.
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Affiliation(s)
- Ida Jonson
- Department of Microbiology, University of Oslo, Oslo University Hospital, Rikshospitalet, P. O. Box 4950 Nydalen, 0424 Oslo, Norway
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11
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Abstract
Dysregulation of DNA damage repair and signalling to cell cycle checkpoints, known as the DNA damage response (DDR), is associated with a predisposition to cancer and affects responses to DNA-damaging anticancer therapy. Dysfunction of one DNA repair pathway may be compensated for by the function of another compensatory DDR pathway, which may be increased and contribute to resistance to DNA-damaging chemotherapy and radiotherapy. Therefore, DDR pathways make an ideal target for therapeutic intervention; first, to prevent or reverse therapy resistance; and second, using a synthetic lethal approach to specifically kill cancer cells that are dependent on a compensatory DNA repair pathway for survival in the context of cancer-associated oxidative and replicative stress. These hypotheses are currently being tested in the laboratory and are being translated into clinical studies.
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Affiliation(s)
- Nicola J Curtin
- Newcastle University, Northern Institute for Cancer Research, Newcastle upon Tyne NE2 4HH, UK.
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12
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Wallace SS, Murphy DL, Sweasy JB. Base excision repair and cancer. Cancer Lett 2012; 327:73-89. [PMID: 22252118 DOI: 10.1016/j.canlet.2011.12.038] [Citation(s) in RCA: 224] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 12/20/2011] [Accepted: 12/24/2011] [Indexed: 01/13/2023]
Abstract
Base excision repair is the system used from bacteria to man to remove the tens of thousands of endogenous DNA damages produced daily in each human cell. Base excision repair is required for normal mammalian development and defects have been associated with neurological disorders and cancer. In this paper we provide an overview of short patch base excision repair in humans and summarize current knowledge of defects in base excision repair in mouse models and functional studies on short patch base excision repair germ line polymorphisms and their relationship to cancer. The biallelic germ line mutations that result in MUTYH-associated colon cancer are also discussed.
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Affiliation(s)
- Susan S Wallace
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, University of Vermont, Burlington, 05405-0068, United States.
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Vogel KS, Perez M, Momand JR, Acevedo-Torres K, Hildreth K, Garcia RA, Torres-Ramos CA, Ayala-Torres S, Prihoda TJ, McMahan CA, Walter CA. Age-related instability in spermatogenic cell nuclear and mitochondrial DNA obtained from Apex1 heterozygous mice. Mol Reprod Dev 2011; 78:906-19. [PMID: 21919107 PMCID: PMC3391697 DOI: 10.1002/mrd.21374] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 07/27/2011] [Indexed: 01/17/2023]
Abstract
The prevalence of spontaneous mutations increases with age in the male germline; consequently, older men have an increased risk of siring children with genetic disease due to de novo mutations. The lacI transgenic mouse can be used to study paternal age effects, and in this system, the prevalence of de novo mutations increases in the male germline at old ages. Mutagenesis is linked with DNA repair capacity, and base excision repair (BER), which can ameliorate spontaneous DNA damage, decreases in nuclear extracts of spermatogenic cells from old mice. Mice heterozygous for a null allele of the Apex1 gene, which encodes apurinic/apyrimidinic endonuclease I (APEN), an essential BER enzyme, display an accelerated increase in spontaneous germline mutagenesis early in life. Here, the consequences of lifelong reduction of APEN on genetic instability in the male germline were examined, for the first time, at middle and old ages. Mutant frequency increased earlier in spermatogenic cells from Apex1(+/-) mice (by 6 months of age). Nuclear DNA damage increased with age in the spermatogenic lineage for both wild-type and Apex1(+/-) mice. By old age, mutant frequencies were similar for wild-type and APEN-deficient mice. Mitochondrial genome repair also depends on APEN, and novel analysis of mitochondrial DNA (mtDNA) damage revealed an increase in the Apex1(+/-) spermatogenic cells by middle age. Thus, Apex1 heterozygosity results in accelerated damage to mtDNA and spontaneous mutagenesis, consistent with an essential role for APEN in maintaining nuclear and mtDNA integrity in spermatogenic cells throughout life.
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Affiliation(s)
- Kristine S. Vogel
- Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900
| | - Marissa Perez
- Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900
| | - Jamila R. Momand
- Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900
| | | | - Kim Hildreth
- Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900
| | - Rebecca A. Garcia
- Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900
| | | | | | - Thomas J. Prihoda
- Department of Pathology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900
| | - C. Alex McMahan
- Department of Pathology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900
| | - Christi A. Walter
- Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900
- Barshop Institute for Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900
- South Texas Veteran’s Health Care System, San Antonio, TX 78229
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14
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Felter SP, Conolly RB, Bercu JP, Bolger PM, Boobis AR, Bos PMJ, Carthew P, Doerrer NG, Goodman JI, Harrouk WA, Kirkland DJ, Lau SS, Llewellyn GC, Preston RJ, Schoeny R, Schnatter AR, Tritscher A, van Velsen F, Williams GM. A proposed framework for assessing risk from less-than-lifetime exposures to carcinogens. Crit Rev Toxicol 2011; 41:507-44. [DOI: 10.3109/10408444.2011.552063] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Hendershot JM, Wolfe AE, O'Brien PJ. Substitution of active site tyrosines with tryptophan alters the free energy for nucleotide flipping by human alkyladenine DNA glycosylase. Biochemistry 2011; 50:1864-74. [PMID: 21244040 PMCID: PMC3059348 DOI: 10.1021/bi101856a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human alkyladenine DNA glycosylase (AAG) locates and excises a wide variety of structurally diverse alkylated and oxidized purine lesions from DNA to initiate the base excision repair pathway. Recognition of a base lesion requires flipping of the damaged nucleotide into a relatively open active site pocket between two conserved tyrosine residues, Y127 and Y159. We have mutated each of these amino acids to tryptophan and measured the kinetic effects on the nucleotide flipping and base excision steps. The Y127W and Y159W mutant proteins have robust glycosylase activity toward DNA containing 1,N(6)-ethenoadenine (εA), within 4-fold of that of the wild-type enzyme, raising the possibility that tryptophan fluorescence could be used to probe the DNA binding and nucleotide flipping steps. Stopped-flow fluorescence was used to compare the time-dependent changes in tryptophan fluorescence and εA fluorescence. For both mutants, the tryptophan fluorescence exhibited two-step binding with essentially identical rate constants as were observed for the εA fluorescence changes. These results provide evidence that AAG forms an initial recognition complex in which the active site pocket is perturbed and the stacking of the damaged base is disrupted. Upon complete nucleotide flipping, there is further quenching of the tryptophan fluorescence with coincident quenching of the εA fluorescence. Although these mutations do not have large effects on the rate constant for excision of εA, there are dramatic effects on the rate constants for nucleotide flipping that result in 40-100-fold decreases in the flipping equilibrium relative to wild-type. Most of this effect is due to an increased rate of unflipping, but surprisingly the Y159W mutation causes a 5-fold increase in the rate constant for flipping. The large effect on the equilibrium for nucleotide flipping explains the greater deleterious effects that these mutations have on the glycosylase activity toward base lesions that are in more stable base pairs.
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Affiliation(s)
- Jenna M. Hendershot
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-5606
| | - Abigail E. Wolfe
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-5606
| | - Patrick J. O'Brien
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-5606
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16
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Nemec AA, Wallace SS, Sweasy JB. Variant base excision repair proteins: contributors to genomic instability. Semin Cancer Biol 2010; 20:320-8. [PMID: 20955798 DOI: 10.1016/j.semcancer.2010.10.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cells sustain endogenous DNA damage at rates greater than 20,000 DNA lesions per cell per day. These damages occur largely as a result of the inherently unstable nature of DNA and the presence of reactive oxygen species within cells. The base excision repair system removes the majority of DNA lesions resulting from endogenous DNA damage. There are several enzymes that function during base excision repair. Importantly, there are over 100 germline single nucleotide polymorphisms in genes that function in base excision repair and that result in non-synonymous amino acid substitutions in the proteins they encode. Somatic variants of these enzymes are also found in human tumors. Variant repair enzymes catalyze aberrant base excision repair. Aberrant base excision repair combined with continuous endogenous DNA damage over time has the potential to lead to a mutator phenotype. Mutations that arise in key growth control genes, imbalances in chromosome number, chromosomal translocations, and loss of heterozygosity can result in the initiation of human cancer or its progression.
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Affiliation(s)
- Antonia A Nemec
- Department of Therapeutic Radiology, 15 York Street, New Haven, CT 06510, United States
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Kang MY, Kim KY, Yoon Y, Kang Y, Kim HB, Youn CK, Kim DH, Kim MH. Ape1/Ref-1 Stimulates GDNF/GFRalpha1-mediated Downstream Signaling and Neuroblastoma Proliferation. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2009; 13:349-56. [PMID: 19915696 DOI: 10.4196/kjpp.2009.13.5.349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 09/21/2009] [Accepted: 10/15/2009] [Indexed: 11/15/2022]
Abstract
We previously reported that glial cell line-derived neurotropic factor (GDNF) receptor alpha1 (GFRalpha1) is a direct target of apurinic/apyrimidinic endonuclease 1 (Ape1/Ref-1). In the present study, we further analyzed the physiological roles of Ape1/Ref-1-induced GFRalpha1 expression in Neuro2a mouse neuroblastoma cells. Ape1/Ref-1 expression caused the clustering of GFRalpha1 immunoreactivity in lipid rafts in response to GDNF. We also found that Ret, a downstream target of GFRalpha1, was functionally activated by GDNF in Ape1/Ref-1-expressing cells. Moreover, GDNF promoted the proliferation of Ape1/Ref-1-expressing Neuro2a cells. Furthermore, GFRalpha1-specific RNA experiments demonstrated that the downregulation of GFRalpha1 by siRNA in Ape1/Ref-1-expressing cells impaired the ability of GDNF to phosphorylate Akt and PLCgamma-1 and to stimulate cellular proliferation. These results show an association between Ape1/Ref-1 and GDNF/GFRalpha signaling, and suggest a potential molecular mechanism for the involvement of Ape1/Ref-1 in neuronal proliferation.
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Affiliation(s)
- Mi-Young Kang
- Department of Pharmacology, DNA Repair Center, Chosun University School of Medicine, Gwangju 501-759, Korea
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18
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Abstract
The DNA base excision repair (BER) pathway repairs alkylation and oxidative DNA damage caused by endogenous and exogenous agents, including chemotherapeutic agents. Upon removal of the damaged base AP endonuclease 1 (Ape1), a critical component of the pathway cleaves the abasic site to facilitate repair. Ape1 is a multifunctional protein which plays a role not only in DNA repair but it also functions as a reduction-oxidation factor, known as Ref-1 in the literature, to increase the DNA binding ability of several transcription factors involved in different growth signaling pathways. Elevated levels of Ape1 have been linked to resistance to chemotherapy, poor prognosis, and poor survival. Reducing the amount of Ape1 protein in cancer cells and tumors using RNA interference and anti-sense oligonucleotide technology sensitizes mammalian tumor cells to a variety of laboratory and chemotherapeutic agents. Therefore, selective inhibition of Ape1's DNA repair activity is a promising avenue to develop novel cancer therapeutics.
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Affiliation(s)
- Aditi Bapat
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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19
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Aag-initiated base excision repair drives alkylation-induced retinal degeneration in mice. Proc Natl Acad Sci U S A 2009; 106:888-93. [PMID: 19139400 DOI: 10.1073/pnas.0807030106] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Vision loss affects >3 million Americans and many more people worldwide. Although predisposing genes have been identified their link to known environmental factors is unclear. In wild-type animals DNA alkylating agents induce photoreceptor apoptosis and severe retinal degeneration. Alkylation-induced retinal degeneration is totally suppressed in the absence of the DNA repair protein alkyladenine DNA glycosylase (Aag) in both differentiating and postmitotic retinas. Moreover, transgenic expression of Aag activity restores the alkylation sensitivity of photoreceptors in Aag null animals. Aag heterozygotes display an intermediate level of retinal degeneration, demonstrating haploinsufficiency and underscoring that Aag expression confers a dominant retinal degeneration phenotype.
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20
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Larsen E, Kleppa L, Meza TJ, Meza-Zepeda LA, Rada C, Castellanos CG, Lien GF, Nesse GJ, Neuberger MS, Laerdahl JK, William Doughty R, Klungland A. Early-onset lymphoma and extensive embryonic apoptosis in two domain-specific Fen1 mice mutants. Cancer Res 2008; 68:4571-9. [PMID: 18559501 DOI: 10.1158/0008-5472.can-08-0168] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Flap endonuclease 1 (FEN1) processes Okazaki fragments in lagging strand DNA synthesis, and FEN1 is involved in several DNA repair pathways. The interaction of FEN1 with the proliferating cell nuclear antigen (PCNA) processivity factor is central to the function of FEN1 in both DNA replication and repair. Here we present two gene-targeted mice with mutations in FEN1. The first mutant mouse carries a single amino acid point mutation in the active site of the nuclease domain of FEN1 (Fen1(E160D/E160D)), and the second mutant mouse contains two amino acid substitutions in the highly conserved PCNA interaction domain of FEN1 (Fen1(DeltaPCNA/DeltaPCNA)). Fen1(E160D/E160D) mice develop a considerably elevated incidence of B-cell lymphomas beginning at 6 months of age, particularly in females. By 16 months of age, more than 90% of the Fen1(E160D/E160D) females have tumors, primarily lymphomas. By contrast, Fen1(DeltaPCNA/DeltaPCNA) mouse embryos show extensive apoptosis in the forebrain and vertebrae area and die around stage E9.5 to E11.5.
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Affiliation(s)
- Elisabeth Larsen
- Centre for Molecular Biology and Neuroscience and Institute of Medical Microbiology, Rikshospitalet Medical Center and University of Oslo, USA
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21
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Kelley MR, Fishel ML. DNA repair proteins as molecular targets for cancer therapeutics. Anticancer Agents Med Chem 2008; 8:417-25. [PMID: 18473726 DOI: 10.2174/187152008784220294] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cancer therapeutics include an ever-increasing array of tools at the disposal of clinicians in their treatment of this disease. However, cancer is a tough opponent in this battle and current treatments which typically include radiotherapy, chemotherapy and surgery are not often enough to rid the patient of his or her cancer. Cancer cells can become resistant to the treatments directed at them and overcoming this drug resistance is an important research focus. Additionally, increasing discussion and research is centering on targeted and individualized therapy. While a number of approaches have undergone intensive and close scrutiny as potential approaches to treat and kill cancer (signaling pathways, multidrug resistance, cell cycle checkpoints, anti-angiogenesis, etc.), much less work has focused on blocking the ability of a cancer cell to recognize and repair the damaged DNA which primarily results from the front line cancer treatments; chemotherapy and radiation. More recent studies on a number of DNA repair targets have produced proof-of-concept results showing that selective targeting of these DNA repair enzymes has the potential to enhance and augment the currently used chemotherapeutic agents and radiation as well as overcoming drug resistance. Some of the targets identified result in the development of effective single-agent anti-tumor molecules. While it is inherently convoluted to think that inhibiting DNA repair processes would be a likely approach to kill cancer cells, careful identification of specific DNA repair proteins is increasingly appearing to be a viable approach in the cancer therapeutic cache.
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Affiliation(s)
- Mark R Kelley
- Department of Pediatrics, Section of Hematology/Oncology, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, 1044 W Walnut St. R4-W302C, Indianapolis, IN 46202, USA.
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22
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Fishel ML, He Y, Reed AM, Chin-Sinex H, Hutchins GD, Mendonca MS, Kelley MR. Knockdown of the DNA repair and redox signaling protein Ape1/Ref-1 blocks ovarian cancer cell and tumor growth. DNA Repair (Amst) 2007; 7:177-86. [PMID: 17974506 DOI: 10.1016/j.dnarep.2007.09.008] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 09/11/2007] [Accepted: 09/18/2007] [Indexed: 12/18/2022]
Abstract
Apurinic endonuclease 1/redox effector factor-1 (Ape1/Ref-1 or Ape1) is an essential protein with two distinct functions. It is a DNA repair enzyme in the base excision repair (BER) pathway and a reduction-oxidation (redox) signaling factor maintaining transcription factors in an active reduced state. Our laboratory previously demonstrated that Ape1 is overexpressed in ovarian cancer and potentially contributes to resistance. Therefore, we utilized siRNA technology to knockdown protein levels of Ape1 in ovarian cancer cell line, SKOV-3x. Knocking Ape1 down had dramatic effects on cell growth in vitro but was not due to an increase in apoptosis and at least partially due to an extension in transit time through S-phase. Similarly, human ovarian tumor xenografts with reduced levels of Ape1 protein demonstrated a dramatic reduction in tumor volume (p<0.01) and also statistically significant (p=0.02) differences in (18)F-fluorodeoxyglucose (FDG) uptake indicating reduced glucose metabolism and cellular proliferation. Ape1's role in DNA repair and redox signaling is important to our basic understanding of ovarian cancer cell growth and these findings strongly support Ape1 as a therapeutic target.
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Affiliation(s)
- Melissa L Fishel
- Department of Pediatrics (Section of Hematology/Oncology), Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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23
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Chen JH, Hales CN, Ozanne SE. DNA damage, cellular senescence and organismal ageing: causal or correlative? Nucleic Acids Res 2007; 35:7417-28. [PMID: 17913751 PMCID: PMC2190714 DOI: 10.1093/nar/gkm681] [Citation(s) in RCA: 312] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Revised: 08/16/2007] [Accepted: 08/17/2007] [Indexed: 01/07/2023] Open
Abstract
Cellular senescence has long been used as a cellular model for understanding mechanisms underlying the ageing process. Compelling evidence obtained in recent years demonstrate that DNA damage is a common mediator for both replicative senescence, which is triggered by telomere shortening, and premature cellular senescence induced by various stressors such as oncogenic stress and oxidative stress. Extensive observations suggest that DNA damage accumulates with age and that this may be due to an increase in production of reactive oxygen species (ROS) and a decline in DNA repair capacity with age. Mutation or disrupted expression of genes that increase DNA damage often result in premature ageing. In contrast, interventions that enhance resistance to oxidative stress and attenuate DNA damage contribute towards longevity. This evidence suggests that genomic instability plays a causative role in the ageing process. However, conflicting findings exist which indicate that ROS production and oxidative damage levels of macromolecules including DNA do not always correlate with lifespan in model animals. Here we review the recent advances in addressing the role of DNA damage in cellular senescence and organismal ageing.
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Affiliation(s)
- Jian-Hua Chen
- Department of Clinical Biochemistry, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 2QR, UK.
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24
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Trapp C, Schwarz M, Epe B. The Peroxisome Proliferator WY-14,643 Promotes Hepatocarcinogenesis Caused by Endogenously Generated Oxidative DNA Base Modifications in Repair-Deficient Csbm/m/Ogg1−/− Mice. Cancer Res 2007; 67:5156-61. [PMID: 17545594 DOI: 10.1158/0008-5472.can-07-0335] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Basal levels of endogenously generated oxidative DNA modifications such as 7,8-dihydro-8-oxoguanine (8-oxoG) are present in apparently all mammalian cells, but their relevance for the generation of spontaneous cancers remains to be established. Both the 8-oxoG levels and the resulting spontaneous mutations are increased in the livers of Csb(m/m)/Ogg1(-/-) mice, which are deficient in the repair of 8-oxoG. In order to determine the consequences of these additional oxidative DNA modifications and mutations and thus assess the tumor initiating potency of this type of endogenous DNA damage, we treated Csb(m/m)/Ogg1(-/-) mice and repair-proficient controls with the peroxisome proliferator WY-14,643 (0.025% ad libitum), a potent inducer of liver cell proliferation. The treatment did not generate any additional oxidative DNA damage; the elevated levels of 8-oxoG in the Csb(m/m)/Ogg1(-/-) mice even decreased. Also, the spontaneous mutation frequencies observed in the lacI gene of BigBlue Csb(m/m)/Ogg1(-/-) mice, which were approximately 3-fold higher than in the repair-proficient mice, declined by 39% under the treatment, whereas the frequencies in the livers of the repair-proficient animals remained unchanged. Preneoplastic lesions (staining positive or negative for glucose-6-phoshatase) developed in the livers of both wild-type and Csb(m/m)/Ogg1(-/-) mice after 30 weeks. Both the numbers and the total volumes of the lesions were approximately 6-fold higher in the repair-deficient mice than in the wild-type mice. The results indicate that spontaneous mutations generated from endogenous oxidative DNA base damage efficiently translate into increased tumorigenesis when cell proliferation is stimulated.
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25
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Fishel ML, Kelley MR. The DNA base excision repair protein Ape1/Ref-1 as a therapeutic and chemopreventive target. Mol Aspects Med 2007; 28:375-95. [PMID: 17560642 DOI: 10.1016/j.mam.2007.04.005] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Accepted: 04/15/2007] [Indexed: 10/23/2022]
Abstract
With our growing understanding of the pathways involved in cell proliferation and signaling, targeted therapies, in the treatment of cancer are entering the clinical arena. New and emerging targets are proteins involved in DNA repair pathways. Inhibition of various proteins in the DNA repair pathways sensitizes cancer cells to DNA damaging agents such as chemotherapy and/or radiation. We study the apurinic endonuclease 1/redox factor-1 (Ape1/Ref-1) and believe that its crucial function in DNA repair and reduction-oxidation or redox signaling make it an excellent target for sensitizing tumor cells to chemotherapy. Ape1/Ref-1 is an essential enzyme in the base excision repair (BER) pathway which is responsible for the repair of DNA caused by oxidative and alkylation damage. As importantly, Ape1/Ref-1 also functions as a redox factor maintaining transcription factors in an active reduced state. Ape1/Ref-1 stimulates the DNA binding activity of numerous transcription factors that are involved in cancer promotion and progression such as AP-1 (Fos/Jun), NFkappaB, HIF-1alpha, CREB, p53 and others. We will discuss what is known regarding the pharmacological targeting of the DNA repair activity, as well as the redox activity of Ape1/Ref-1, and explore the budding clinical utility of inhibition of either of these functions in cancer treatment. A brief discussion of the effect of polymorphisms in its DNA sequence is included because of Ape1/Ref-1's importance to maintenance and integrity of the genome. Experimental modification of Ape1/Ref-1 activity changes the response of cells and of organisms to DNA damaging agents, suggesting that Ape1/Ref-1 may also be a productive target of chemoprevention. In this review, we will provide an overview of Ape1/Ref-1's activities and explore the potential of this protein as a target in cancer treatment as well as its role in chemoprevention.
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Affiliation(s)
- Melissa L Fishel
- Department of Pediatrics (Section of Hematology/Oncology), Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, United States
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26
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Shaw P, Clarke AR. Murine models of intestinal cancer: recent advances. DNA Repair (Amst) 2007; 6:1403-12. [PMID: 17376749 DOI: 10.1016/j.dnarep.2007.02.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Accepted: 02/14/2007] [Indexed: 10/23/2022]
Abstract
Since the advent of strategies capable of manipulating the germline of mice, there has been a rapid expansion in the number of murine models of intestinal cancer. These have largely been developed with the specific aim of elucidating the molecular mechanisms underlying tumour initiation and progression. In attempting this goal, these models have become increasingly sophisticated, allowing ever more precise recapitulation of the genetic events that underlie human disease. Such technological advances include both temporal and spatial control over mutant allele expression. This review highlights some of notable recent advances using these approaches, with particular focus upon the role of a number of key signalling pathways, DNA repair mechanisms and inflammation.
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Affiliation(s)
- Paul Shaw
- Cardiff School of Biosciences, Cardiff University, Cardiff, UK
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