1
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Excessive Folic Acid Mimics Folate Deficiency in Human Lymphocytes. Curr Issues Mol Biol 2022; 44:1452-1462. [PMID: 35723355 PMCID: PMC9164024 DOI: 10.3390/cimb44040097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/14/2022] [Accepted: 03/20/2022] [Indexed: 12/19/2022] Open
Abstract
Food fortification with synthetic folic acid (FA), along with supplementation, results in a marked increase in the population total of serum folates and unmetabolized folic acid (UMFA). Despite the success in reducing neural tube defects at birth in the intended target population (women of childbearing age), the potential deleterious effects of chronically high levels of UMFA in susceptible segments of the population require further investigation. In this study, we examine the effects of FA concentrations, ranging from depletion to supraphysiological levels, on markers of proliferation, DNA methylation, and DNA damage and repair in a human lymphoblastoid cell line (LCL). We note that both low and high levels of FA similarly impact global DNA methylation, cytome biomarkers measured through the CBMN assay, DNA damage induced by oxidative stress, and DNA base excision repair gene expression.
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2
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Xicola RM, Clark JR, Carroll T, Alvikas J, Marwaha P, Regan MR, Lopez-Giraldez F, Choi J, Emmadi R, Alagiozian-Angelova V, Kupfer SS, Ellis NA, Llor X. Implication of DNA repair genes in Lynch-like syndrome. Fam Cancer 2019; 18:331-342. [PMID: 30989425 DOI: 10.1007/s10689-019-00128-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Many colorectal cancers (CRCs) that exhibit microsatellite instability (MSI) are not explained by MLH1 promoter methylation or germline mutations in mismatch repair (MMR) genes, which cause Lynch syndrome (LS). Instead, these Lynch-like syndrome (LLS) patients have somatic mutations in MMR genes. However, many of these patients are young and have relatives with cancer, suggesting a hereditary entity. We performed germline sequence analysis in LLS patients and determined their tumor's mutational profiles using FFPE DNA. Six hundred and fifty-four consecutive CRC patients were screened for suspected LS using MSI and absence of MLH1 methylation. Suspected LS cases were exome sequenced to identify germline and somatic mutations. Single nucleotide variants were used to characterize mutational signatures. We identified 23 suspected LS cases. Germline sequence analysis of 16 available samples identified five cases with LS mutations and 11 cases without LS mutations, LLS. Most LLS tumors had a combination of somatic MMR gene mutation and loss of heterozygosity. LLS patients were relatively young and had excess first-degree relatives with cancer. Four of the 11 LLS patients had rare likely pathogenic variants in genes that maintain genome integrity. Moreover, tumors from this group had a distinct mutational signature compared to tumors from LLS patients lacking germline mutations in these genes. In summary, more than a third of the LLS patients studied had germline mutations in genes that maintain genome integrity and their tumors had a distinct mutational signature. The possibility of hereditary factors in LLS warrants further studies so counseling can be properly informed.
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Affiliation(s)
- Rosa M Xicola
- Department of Internal Medicine and Cancer Center, Yale University School of Medicine, P. O. Box 208019, 333 Cedar Street/LMP 1080, New Haven, CT, 06520-8019, USA
| | - Julia R Clark
- Department of Medicine and Cancer Center, University of Illinois at Chicago, 1020N CSB, Chicago, IL, 60612, USA
| | - Timothy Carroll
- Department of Medicine and Cancer Center, University of Illinois at Chicago, 1020N CSB, Chicago, IL, 60612, USA
| | - Jurgis Alvikas
- Department of Medicine and Cancer Center, University of Illinois at Chicago, 1020N CSB, Chicago, IL, 60612, USA
| | - Priti Marwaha
- Department of Medicine and Cancer Center, University of Illinois at Chicago, 1020N CSB, Chicago, IL, 60612, USA
| | - Maureen R Regan
- Department of Medicine and Cancer Center, University of Illinois at Chicago, 1020N CSB, Chicago, IL, 60612, USA
| | - Francesc Lopez-Giraldez
- Yale Center for Genome Analysis, Yale University, 830 West Campus Drive, Orange, CT, 06477, USA
| | - Jungmin Choi
- Department of Genetics and Yale Center for Genome Analysis, Yale University School of Medicine, 830 West Campus Drive, Orange, CT, 06477, USA
| | - Rajyasree Emmadi
- Department of Pathology, University of Illinois at Chicago, 840 S. Wood St., Suite 130 CSN, Chicago, IL, 60612, USA
| | | | - Sonia S Kupfer
- Center for Clinical Cancer Genetics, The University of Chicago, 900 East 57th Street, Chicago, IL, 60637, USA
| | - Nathan A Ellis
- Department of Cellular and Molecular Medicine, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724-5024, USA
| | - Xavier Llor
- Department of Internal Medicine and Cancer Center, Yale University School of Medicine, P. O. Box 208019, 333 Cedar Street/LMP 1080, New Haven, CT, 06520-8019, USA.
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3
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OGG1-initiated base excision repair exacerbates oxidative stress-induced parthanatos. Cell Death Dis 2018; 9:628. [PMID: 29795387 PMCID: PMC5967321 DOI: 10.1038/s41419-018-0680-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/29/2018] [Accepted: 03/30/2018] [Indexed: 02/01/2023]
Abstract
Oxidative stress-induced DNA damage has been well acknowledged as a major cause leading to cell death, which is etiologically linked to ischemic injury and degenerative alterations. The most common oxidation product of DNA is base lesion 8-oxo-7,8-dihydroguanine (8-oxoG), which is repaired by 8-oxoG glycosylase1 (OGG1)-initiated baseexcision repair (BER) pathway (OGG1-BER); however, the role of OGG1-BER in oxidative stress-induced cell death is poorly investigated. DNA strand breaks and apurinic/apyrimidinic (AP) sites are effective substrates to activate DNA damage sensor poly(ADP-ribose) polymerase 1 (PARP1). Overactivation of PARP1 is associated with apoptosis-inducing factor (AIF)-mediated and caspase-independent cell death (parthanatos). We hypothesized that after an excessive oxidative insult, OGG1-BER-generated strand breaks result in hyperactivation of PARP1 and consequently cell death. To test, wild type, knockout, siRNA-depleted MEFs and neuroblastoma cells, or those expressing repair-deficient OGG1 mutants were oxidatively stressed and the role of OGG1 was examined. Results showed that OGG1-BER further increases the levels of ROS-induced DNA damage by generating repair intermediates, leading to PARP1 overactivation and cell death. Cells lacking or expressing repair-deficient OGG1 showed lower levels of DNA strand lesions, PARP1 activation, and nuclear translocation of apoptosis-inducing factor, resulting in the increased resistance to ROS-induced parthanatos. These results suggested that OGG1 guards genome integrity through either lesion repair or elimination of cells with malignant potential, to maintain the homeostasis of the host, which might depend on the magnitude of guanine oxidation.
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4
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Development of a Cell-Based Assay for Measuring Base Excision Repair Responses. Sci Rep 2017; 7:13007. [PMID: 29021553 PMCID: PMC5636817 DOI: 10.1038/s41598-017-12963-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 09/18/2017] [Indexed: 12/24/2022] Open
Abstract
Base excision repair (BER) is the predominant pathway for coping with most forms of hydrolytic, oxidative or alkylative DNA damage. Measuring BER capacity in living cells is valuable for both basic science applications and epidemiological studies, since deficiencies in this pathway have been associated with cancer susceptibility and other adverse health outcomes. At present, there is an ongoing effort to develop methods to effectively quantify the rate of BER as a whole. We present a variation of a previously described “Oligonucleotide Retrieval Assay” designed to measure DNA excision repair that is capable of quantifying the rate of repair of thymine glycol in a variety of human cells with a high degree of sensitivity.
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5
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Coskun E, Jaruga P, Reddy PT, Dizdaroglu M. Extreme Expression of DNA Repair Protein Apurinic/Apyrimidinic Endonuclease 1 (APE1) in Human Breast Cancer As Measured by Liquid Chromatography and Isotope Dilution Tandem Mass Spectrometry. Biochemistry 2015; 54:5787-90. [PMID: 26359670 DOI: 10.1021/acs.biochem.5b00928] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is a DNA repair protein and plays other important roles. Increased levels of APE1 in cancer have been reported. However, available methods for measuring APE1 levels are indirect and not quantitative. We previously developed an approach using liquid chromatography and tandem mass spectrometry with isotope dilution to accurately measure APE1 levels. Here, we applied this methodology to measure APE1 levels in normal and cancerous human breast tissues. Extreme expression of APE1 in malignant tumors was observed, suggesting that breast cancer cells may require APE1 for survival. Accurate measurement of APE1 may be essential for the development of novel treatment strategies and APE1 inhibitors as anticancer drugs.
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Affiliation(s)
- Erdem Coskun
- Biomolecular Measurement Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.,Department of Toxicology, Faculty of Pharmacy, Gazi University , Ankara, Turkey
| | - Pawel Jaruga
- Biomolecular Measurement Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Prasad T Reddy
- Biomolecular Measurement Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Miral Dizdaroglu
- Biomolecular Measurement Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
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6
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Hinz JM, Mao P, McNeill DR, Wilson DM. Reduced Nuclease Activity of Apurinic/Apyrimidinic Endonuclease (APE1) Variants on Nucleosomes: IDENTIFICATION OF ACCESS RESIDUES. J Biol Chem 2015; 290:21067-21075. [PMID: 26134573 PMCID: PMC4543664 DOI: 10.1074/jbc.m115.665547] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 06/30/2015] [Indexed: 11/06/2022] Open
Abstract
Non-coding apurinic/apyrimidinic (AP) sites are generated at high frequency in genomic DNA via spontaneous hydrolytic, damage-induced or enzyme-mediated base release. AP endonuclease 1 (APE1) is the predominant mammalian enzyme responsible for initiating removal of mutagenic and cytotoxic abasic lesions as part of the base excision repair (BER) pathway. We have examined here the ability of wild-type (WT) and a collection of variant/mutant APE1 proteins to cleave at an AP site within a nucleosome core particle. Our studies indicate that, in comparison to the WT protein and other variant/mutant enzymes, the incision activity of the tumor-associated variant R237C and the rare population variant G241R are uniquely hypersensitive to nucleosome complexes in the vicinity of the AP site. This defect appears to stem from an abnormal interaction of R237C and G241R with abasic DNA substrates, but is not simply due to a DNA binding defect, as the site-specific APE1 mutant Y128A, which displays markedly reduced AP-DNA complex stability, did not exhibit a similar hypersensitivity to nucleosome structures. Notably, this incision defect of R237C and G241R was observed on a pre-assembled DNA glycosylase·AP-DNA complex as well. Our results suggest that the BER enzyme, APE1, has acquired distinct surface residues that permit efficient processing of AP sites within the context of protein-DNA complexes independent of classic chromatin remodeling mechanisms.
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Affiliation(s)
- John M Hinz
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164-7520 and.
| | - Peng Mao
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164-7520 and
| | - Daniel R McNeill
- Laboratory of Molecular Gerontology, National Institute on Aging, IRP, National Institutes of Health, Baltimore, Maryland 21224
| | - David M Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, IRP, National Institutes of Health, Baltimore, Maryland 21224
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7
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Reddy PT, Jaruga P, Nelson BC, Lowenthal MS, Jemth AS, Loseva O, Coskun E, Helleday T, Dizdaroglu M. Production, Purification, and Characterization of ¹⁵N-Labeled DNA Repair Proteins as Internal Standards for Mass Spectrometric Measurements. Methods Enzymol 2015; 566:305-32. [PMID: 26791985 DOI: 10.1016/bs.mie.2015.06.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Oxidatively induced DNA damage is caused in living organisms by a variety of damaging agents, resulting in the formation of a multiplicity of lesions, which are mutagenic and cytotoxic. Unless repaired by DNA repair mechanisms before DNA replication, DNA lesions can lead to genomic instability, which is one of the hallmarks of cancer. Oxidatively induced DNA damage is mainly repaired by base excision repair pathway with the involvement of a plethora of proteins. Cancer tissues develop greater DNA repair capacity than normal tissues by overexpressing DNA repair proteins. Increased DNA repair in tumors that removes DNA lesions generated by therapeutic agents before they became toxic is a major mechanism in the development of therapy resistance. Evidence suggests that DNA repair capacity may be a predictive biomarker of patient response. Thus, knowledge of DNA-protein expressions in disease-free and cancerous tissues may help predict and guide development of treatments and yield the best therapeutic response. Our laboratory has developed methodologies that use mass spectrometry with isotope dilution for the measurement of expression of DNA repair proteins in human tissues and cultured cells. For this purpose, full-length (15)N-labeled analogs of a number of human DNA repair proteins have been produced and purified to be used as internal standards for positive identification and accurate quantification. This chapter describes in detail the protocols of this work. The use of (15)N-labeled proteins as internal standards for the measurement of several DNA repair proteins in vivo is also presented.
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Affiliation(s)
- Prasad T Reddy
- Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology and the University of Maryland, Rockville, Maryland, USA.
| | - Pawel Jaruga
- Biochemical Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Bryant C Nelson
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Mark S Lowenthal
- Biochemical Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Ann-Sofie Jemth
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Olga Loseva
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Erdem Coskun
- Biochemical Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Thomas Helleday
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Miral Dizdaroglu
- Biochemical Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland, USA.
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8
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Smith CL, Eppig JT. Expanding the mammalian phenotype ontology to support automated exchange of high throughput mouse phenotyping data generated by large-scale mouse knockout screens. J Biomed Semantics 2015; 6:11. [PMID: 25825651 PMCID: PMC4378007 DOI: 10.1186/s13326-015-0009-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 03/03/2015] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND A vast array of data is about to emerge from the large scale high-throughput mouse knockout phenotyping projects worldwide. It is critical that this information is captured in a standardized manner, made accessible, and is fully integrated with other phenotype data sets for comprehensive querying and analysis across all phenotype data types. The volume of data generated by the high-throughput phenotyping screens is expected to grow exponentially, thus, automated methods and standards to exchange phenotype data are required. RESULTS The IMPC (International Mouse Phenotyping Consortium) is using the Mammalian Phenotype (MP) ontology in the automated annotation of phenodeviant data from high throughput phenotyping screens. 287 new term additions with additional hierarchy revisions were made in multiple branches of the MP ontology to accurately describe the results generated by these high throughput screens. CONCLUSIONS Because these large scale phenotyping data sets will be reported using the MP as the common data standard for annotation and data exchange, automated importation of these data to MGI (Mouse Genome Informatics) and other resources is possible without curatorial effort. Maximum biomedical value of these mutant mice will come from integrating primary high-throughput phenotyping data with secondary, comprehensive phenotypic analyses combined with published phenotype details on these and related mutants at MGI and other resources.
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Affiliation(s)
- Cynthia L Smith
- Mouse Genome Informatics, The Jackson Laboratory, Bar Harbor, ME 04609 USA
| | - Janan T Eppig
- Mouse Genome Informatics, The Jackson Laboratory, Bar Harbor, ME 04609 USA
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9
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Brenerman BM, Illuzzi JL, Wilson DM. Base excision repair capacity in informing healthspan. Carcinogenesis 2014; 35:2643-52. [PMID: 25355293 PMCID: PMC4247524 DOI: 10.1093/carcin/bgu225] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 10/22/2014] [Accepted: 10/24/2014] [Indexed: 12/21/2022] Open
Abstract
Base excision repair (BER) is a frontline defense mechanism for dealing with many common forms of endogenous DNA damage, several of which can drive mutagenic or cell death outcomes. The pathway engages proteins such as glycosylases, abasic endonucleases, polymerases and ligases to remove substrate modifications from DNA and restore the genome back to its original state. Inherited mutations in genes related to BER can give rise to disorders involving cancer, immunodeficiency and neurodegeneration. Studies employing genetically defined heterozygous (haploinsufficient) mouse models indicate that partial reduction in BER capacity can increase vulnerability to both spontaneous and exposure-dependent pathologies. In humans, measurement of BER variation has been imperfect to this point, yet tools to assess BER in epidemiological surveys are steadily evolving. We provide herein an overview of the BER pathway and discuss the current efforts toward defining the relationship of BER defects with disease susceptibility.
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Affiliation(s)
- Boris M Brenerman
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Jennifer L Illuzzi
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - David M Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
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10
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Oxidatively induced DNA damage and its repair in cancer. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 763:212-45. [PMID: 25795122 DOI: 10.1016/j.mrrev.2014.11.002] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 11/03/2014] [Accepted: 11/04/2014] [Indexed: 12/28/2022]
Abstract
Oxidatively induced DNA damage is caused in living organisms by endogenous and exogenous reactive species. DNA lesions resulting from this type of damage are mutagenic and cytotoxic and, if not repaired, can cause genetic instability that may lead to disease processes including carcinogenesis. Living organisms possess DNA repair mechanisms that include a variety of pathways to repair multiple DNA lesions. Mutations and polymorphisms also occur in DNA repair genes adversely affecting DNA repair systems. Cancer tissues overexpress DNA repair proteins and thus develop greater DNA repair capacity than normal tissues. Increased DNA repair in tumors that removes DNA lesions before they become toxic is a major mechanism for development of resistance to therapy, affecting patient survival. Accumulated evidence suggests that DNA repair capacity may be a predictive biomarker for patient response to therapy. Thus, knowledge of DNA protein expressions in normal and cancerous tissues may help predict and guide development of treatments and yield the best therapeutic response. DNA repair proteins constitute targets for inhibitors to overcome the resistance of tumors to therapy. Inhibitors of DNA repair for combination therapy or as single agents for monotherapy may help selectively kill tumors, potentially leading to personalized therapy. Numerous inhibitors have been developed and are being tested in clinical trials. The efficacy of some inhibitors in therapy has been demonstrated in patients. Further development of inhibitors of DNA repair proteins is globally underway to help eradicate cancer.
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11
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Kirkali G, Jaruga P, Reddy PT, Tona A, Nelson BC, Li M, Wilson DM, Dizdaroglu M. Identification and quantification of DNA repair protein apurinic/apyrimidinic endonuclease 1 (APE1) in human cells by liquid chromatography/isotope-dilution tandem mass spectrometry. PLoS One 2013; 8:e69894. [PMID: 23922845 PMCID: PMC3726725 DOI: 10.1371/journal.pone.0069894] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/13/2013] [Indexed: 11/18/2022] Open
Abstract
Unless repaired, DNA damage can drive mutagenesis or cell death. DNA repair proteins may therefore be used as biomarkers in disease etiology or therapeutic response prediction. Thus, the accurate determination of DNA repair protein expression and genotype is of fundamental importance. Among DNA repair proteins involved in base excision repair, apurinic/apyrimidinic endonuclease 1 (APE1) is the major endonuclease in mammals and plays important roles in transcriptional regulation and modulating stress responses. Here, we present a novel approach involving LC-MS/MS with isotope-dilution to positively identify and accurately quantify APE1 in human cells and mouse tissue. A completely 15N-labeled full-length human APE1 was produced and used as an internal standard. Fourteen tryptic peptides of both human APE1 (hAPE1) and 15N-labeled hAPE1 were identified following trypsin digestion. These peptides matched the theoretical peptides expected from trypsin digestion and provided a statistically significant protein score that would unequivocally identify hAPE1. Using the developed methodology, APE1 was positively identified and quantified in nuclear and cytoplasmic extracts of multiple human cell lines and mouse liver using selected-reaction monitoring of typical mass transitions of the tryptic peptides. We also show that the methodology can be applied to the identification of hAPE1 variants found in the human population. The results describe a novel approach for the accurate measurement of wild-type and variant forms of hAPE1 in vivo, and ultimately for defining the role of this protein in disease development and treatment responses.
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Affiliation(s)
- Güldal Kirkali
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America
| | - Pawel Jaruga
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America
| | - Prasad T. Reddy
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America
| | - Alessandro Tona
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America
| | - Bryant C. Nelson
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America
| | - Mengxia Li
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - David M. Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Miral Dizdaroglu
- Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America
- * E-mail:
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12
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Illuzzi JL, Harris NA, Manvilla BA, Kim D, Li M, Drohat AC, Wilson DM. Functional assessment of population and tumor-associated APE1 protein variants. PLoS One 2013; 8:e65922. [PMID: 23776569 PMCID: PMC3679070 DOI: 10.1371/journal.pone.0065922] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 04/29/2013] [Indexed: 01/15/2023] Open
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is the predominant AP site repair enzyme in mammals. APE1 also maintains 3'-5' exonuclease and 3'-repair activities, and regulates transcription factor DNA binding through its REF-1 function. Since complete or severe APE1 deficiency leads to embryonic lethality and cell death, it has been hypothesized that APE1 protein variants with slightly impaired function will contribute to disease etiology. Our data indicate that except for the endometrial cancer-associated APE1 variant R237C, the polymorphic variants Q51H, I64V and D148E, the rare population variants G241R, P311S and A317V, and the tumor-associated variant P112L exhibit normal thermodynamic stability of protein folding; abasic endonuclease, 3'-5' exonuclease and REF-1 activities; coordination during the early steps of base excision repair; and intracellular distribution when expressed exogenously in HeLa cells. The R237C mutant displayed reduced AP-DNA complex stability, 3'-5' exonuclease activity and 3'-damage processing. Re-sequencing of the exonic regions of APE1 uncovered no novel amino acid substitutions in the 60 cancer cell lines of the NCI-60 panel, or in HeLa or T98G cancer cell lines; only the common D148E and Q51H variants were observed. Our results indicate that APE1 missense mutations are seemingly rare and that the cancer-associated R237C variant may represent a reduced-function susceptibility allele.
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Affiliation(s)
- Jennifer L. Illuzzi
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Nicole A. Harris
- Department of Cardiopathology, Sanford Burnham Medical Research Institute, Orlando, Florida, United States of America
| | - Brittney A. Manvilla
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Daemyung Kim
- Department of Genetic Engineering, Cheongju University, Cheongju, Republic of Korea
| | - Mengxia Li
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Alexander C. Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - David M. Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
- * E-mail:
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13
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Abstract
Base excision repair (BER) is a frontline repair system that is responsible for maintaining genome integrity and thus preventing premature aging, cancer and many other human diseases by repairing thousands of DNA lesions and strand breaks continuously caused by endogenous and exogenous mutagens. This fundamental and essential function of BER not only necessitates tight control of the continuous availability of basic components for fast and accurate repair, but also requires temporal and spatial coordination of BER and cell cycle progression to prevent replication of damaged DNA. The major goal of this review is to critically examine controversial and newly emerging questions about mammalian BER pathways, mechanisms regulating BER capacity, BER responses to DNA damage and their links to checkpoint control of DNA replication.
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Affiliation(s)
- Grigory L Dianov
- Department of Oncology, Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK.
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14
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Abstract
Within the last decade, multiple novel congenital human disorders have been described with genetic defects in known and/or novel components of several well-known DNA repair and damage response pathways. Examples include disorders of impaired nucleotide excision repair, DNA double-strand and single-strand break repair, as well as compromised DNA damage-induced signal transduction including phosphorylation and ubiquitination. These conditions further reinforce the importance of multiple genome stability pathways for health and development in humans. Furthermore, these conditions inform our knowledge of the biology of the mechanics of genome stability and in some cases provide potential routes to help exploit these pathways therapeutically. Here, I will review a selection of these exciting findings from the perspective of the disorders themselves, describing how they were identified, how genotype informs phenotype, and how these defects contribute to our growing understanding of genome stability pathways.
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Affiliation(s)
- Mark O'Driscoll
- Human DNA Damage Response Disorders Group Genome Damage and Stability Centre, University of Sussex, Brighton, East Sussex BN1 9RQ, United Kingdom
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15
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Folate and colorectal cancer in rodents: a model of DNA repair deficiency. JOURNAL OF ONCOLOGY 2012; 2012:105949. [PMID: 23093960 PMCID: PMC3474250 DOI: 10.1155/2012/105949] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 06/07/2012] [Indexed: 12/31/2022]
Abstract
Fortification of grains has resulted in a positive public health outcome vis-a-vis reduced incidence of neural tube defects. Whether folate has a correspondingly beneficial effect on other disease outcomes is less clear. A role for dietary folate in the prevention of colorectal cancer has been established through epidemiological data. Experimental data aiming to further elucidate this relationship has been somewhat equivocal. Studies report that folate depletion increases DNA damage, mutagenesis, and chromosomal instability, all suggesting inhibited DNA repair. While these data connecting folate depletion and inhibition of DNA repair are convincing, we also present data demonstrating that genetic inhibition of DNA repair is protective in the development of preneoplastic colon lesions, both when folate is depleted and when it is not. The purpose of this paper is to (1) give an overview of the data demonstrating a DNA repair defect in response to folate depletion, and (2) critically compare and contrast the experimental designs utilized in folate/colorectal cancer research and the corresponding impact on tissue folate status and critical colorectal cancer endpoints. Our analysis suggests that there is still an important need for a comprehensive evaluation of the impact of differential dietary prescriptions on blood and tissue folate status.
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