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Abstract
Hydrogen peroxide (H2O2) is a crucial substrate for thyroid peroxidase, a key enzyme involved in thyroid hormone synthesis. However, as a potent oxidant, H2O2 might also be responsible for the high level of oxidative DNA damage observed in thyroid tissues, such as DNA base lesions and strand breakages, which promote chromosomal instability and contribute to the development of tumours. Although the role of H2O2 in thyroid hormone synthesis is well established, its precise mechanisms of action in pathological processes are still under investigation. The NADPH oxidase/dual oxidase family are the only oxidoreductases whose primary function is to produce reactive oxygen species. As such, the function and expression of these enzymes are tightly regulated. Thyrocytes express dual oxidase 2, which produces most of the H2O2 for thyroid hormone synthesis. Thyrocytes also express dual oxidase 1 and NADPH oxidase 4, but the roles of these enzymes are still unknown. Here, we review the structure, expression, localization and function of these enzymes. We focus on their potential role in thyroid cancer, which is characterized by increased expression of these enzymes.
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Affiliation(s)
- Rabii Ameziane-El-Hassani
- Institut Gustave Roussy, UMR 8200 CNRS, 114 Rue Edouard Vaillant, Villejuif F-94805, France
- Unité de Biologie et de Recherche Médicale, Centre National de l'Energie, des Sciences et des Techniques Nucléaires, BP 1382, Rabat M-10001, Morocco
| | - Martin Schlumberger
- Institut Gustave Roussy, UMR 8200 CNRS, 114 Rue Edouard Vaillant, Villejuif F-94805, France
- University Paris-Saclay, Orsay F-91400, France
| | - Corinne Dupuy
- Institut Gustave Roussy, UMR 8200 CNRS, 114 Rue Edouard Vaillant, Villejuif F-94805, France
- University Paris-Saclay, Orsay F-91400, France
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NADPH oxidase DUOX1 promotes long-term persistence of oxidative stress after an exposure to irradiation. Proc Natl Acad Sci U S A 2015; 112:5051-6. [PMID: 25848056 DOI: 10.1073/pnas.1420707112] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ionizing radiation (IR) causes not only acute tissue damage, but also late effects in several cell generations after the initial exposure. The thyroid gland is one of the most sensitive organs to the carcinogenic effects of IR, and we have recently highlighted that an oxidative stress is responsible for the chromosomal rearrangements found in radio-induced papillary thyroid carcinoma. Using both a human thyroid cell line and primary thyrocytes, we investigated the mechanism by which IR induces the generation of reactive oxygen species (ROS) several days after irradiation. We focused on NADPH oxidases, which are specialized ROS-generating enzymes known as NOX/DUOX. Our results show that IR induces delayed NADPH oxidase DUOX1-dependent H2O2 production in a dose-dependent manner, which is sustained for several days. We report that p38 MAPK, activated after IR, increased DUOX1 via IL-13 expression, leading to persistent DNA damage and growth arrest. Pretreatment of cells with catalase, a scavenger of H2O2, or DUOX1 down-regulation by siRNA abrogated IR-induced DNA damage. Analysis of human thyroid tissues showed that DUOX1 is elevated not only in human radio-induced thyroid tumors, but also in sporadic thyroid tumors. Taken together, our data reveal a key role of DUOX1-dependent H2O2 production in long-term persistent radio-induced DNA damage. Our data also show that DUOX1-dependent H2O2 production, which induces DNA double-strand breaks, can cause genomic instability and promote the generation of neoplastic cells through its mutagenic effect.
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Kashino G, Suzuki K, Kodama S, Watanabe M, Prise KM. Increased susceptibility to delayed genetic effects of low dose X-irradiation in DNA repair deficient cells. Int J Radiat Biol 2012; 89:295-300. [DOI: 10.3109/09553002.2013.752596] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Yoshida T, Goto S, Kawakatsu M, Urata Y, Li TS. Mitochondrial dysfunction, a probable cause of persistent oxidative stress after exposure to ionizing radiation. Free Radic Res 2012; 46:147-53. [PMID: 22126415 DOI: 10.3109/10715762.2011.645207] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Several recent studies have suggested that the reactive oxygen species (ROS) generated from mitochondria contribute to genomic instability after exposure of the cells to ionizing radiation, but the mechanism of this process is not yet fully understood. We examined the hypothesis that irradiation induces mitochondrial dysfunction to cause persistent oxidative stress, which contributes to genomic instability. After the exposure of cells to 5 Gy gamma-ray irradiation, we found that the irradiation induced the following changes in a clear pattern of time courses. First, a robust increase of intracellular ROS levels occurred within minutes, but the intracellular ROS disappeared within 30 min. Then the mitochondrial dysfunction was detected at 12 h after irradiation, as indicated by the decreased activity of NADH dehydrogenase (Complex I), the most important enzyme in regulating the release of ROS from the mitochondrial electron transport chain (ETC). Finally, a significant increase of ROS levels in the mitochondria and the oxidation of mitochondrial DNA were observed in cells at 24 h or later after irradiation. Although further experiments are required, results in this study support the hypothesis that mitochondrial dysfunction causes persistent oxidative stress that may contribute to promote radiation-induced genomic instability.
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Affiliation(s)
- Takako Yoshida
- Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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Zuo YH, Dang XH, Zhang HF, Liu JG, Duan ZK, Wang ZW, Tong J. Genomic instability induced by ionizing radiation in human hepatocytes. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2012; 75:700-706. [PMID: 22757674 DOI: 10.1080/15287394.2012.690087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The aim of this study was to characterize genomic instability induced by ionizing radiation (IR) in human hepatocytes as reflected by alterations in cloning efficiency, micronucleus (MN) frequency, and apoptosis. The human normal liver 7702 cell line (HL7702) was subjected to initial irradiation of (60)Co-γ ray at doses of 0 (control group), 2, 4, 6, 8, or 10 Gy in each group. Progeny of surviving cells from a second irradiation at dose of 2 Gy were cultured for 15 passages until they were transferred. The cloning efficiency, MN frequency, and apoptotic rate were measured after the initial irradiation, and repeated at passage 15 before and after the second irradiation. The initial irradiation resulted in a dose-dependent decline in cloning efficiency and an increase in MN frequency and apoptotic rate. At passage 15 in progeny of initially irradiated cells, cloning efficiency, MN frequency returned to control levels while apoptotic rate rose. After the second irradiation, cloning efficiency fell while a rise in MN frequency and apoptosis occurred. Our results show that the second irradiation may further enhance cell progeny injury induced by initial irradiation, such that genomic instability that may be difficult to detect after one irradiation is more apparent with subsequent irradiation.
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Affiliation(s)
- Ya-Hui Zuo
- Division of Radiology and Environmental Medicine, China Institute for Radiation Protection, Taiyuan, China
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Kobashigawa S, Suzuki K, Yamashita S. Ionizing radiation accelerates Drp1-dependent mitochondrial fission, which involves delayed mitochondrial reactive oxygen species production in normal human fibroblast-like cells. Biochem Biophys Res Commun 2011; 414:795-800. [DOI: 10.1016/j.bbrc.2011.10.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 10/02/2011] [Indexed: 10/16/2022]
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Ilnytskyy Y, Kovalchuk O. Non-targeted radiation effects-an epigenetic connection. Mutat Res 2011; 714:113-25. [PMID: 21784089 DOI: 10.1016/j.mrfmmm.2011.06.014] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 06/24/2011] [Accepted: 06/29/2011] [Indexed: 01/18/2023]
Abstract
Ionizing radiation (IR) is a pivotal diagnostic and treatment modality, yet it is also a potent genotoxic agent that causes genome instability and carcinogenesis. While modern cancer radiation therapy has led to increased patient survival rates, the risk of radiation treatment-related complications is becoming a growing problem. IR-induced genome instability has been well-documented in directly exposed cells and organisms. It has also been observed in distant 'bystander' cells. Enigmatically, increased instability is even observed in progeny of pre-conceptually exposed animals, including humans. The mechanisms by which it arises remain obscure and, recently, they have been proposed to be epigenetic in nature. Three major epigenetic phenomena include DNA methylation, histone modifications and small RNA-mediated silencing. This review focuses on the role of DNA methylation and small RNAs in directly exposed and bystander tissues and in IR-induced transgenerational effects. Here, we present evidence that IR-mediated effects are maintained by epigenetic mechanisms.
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Affiliation(s)
- Yaroslav Ilnytskyy
- Department of Biological Sciences, University of Lethbridge, Lethbridge T1K 3M4, Alberta, Canada
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Aypar U, Morgan WF, Baulch JE. Radiation-induced genomic instability: Are epigenetic mechanisms the missing link? Int J Radiat Biol 2010; 87:179-91. [DOI: 10.3109/09553002.2010.522686] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Ameziane-El-Hassani R, Boufraqech M, Lagente-Chevallier O, Weyemi U, Talbot M, Métivier D, Courtin F, Bidart JM, El Mzibri M, Schlumberger M, Dupuy C. Role of H2O2 in RET/PTC1 chromosomal rearrangement produced by ionizing radiation in human thyroid cells. Cancer Res 2010; 70:4123-32. [PMID: 20424115 DOI: 10.1158/0008-5472.can-09-4336] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
During childhood, the thyroid gland is one of the most sensitive organs to the carcinogenetic effects of ionizing radiation that may lead to papillary thyroid carcinoma (PTC) associated with RET/PTC oncogene rearrangement. Exposure to ionizing radiation induces a transient "oxidative burst" through radiolysis of water, which can cause DNA damage and mediates part of the radiation effects. H(2)O(2) is a potent DNA-damaging agent that induces DNA double-strand breaks, and consequently, chromosomal aberrations. Irradiation by 5 Gy X-ray increased extracellular H(2)O(2). Therefore, we investigated the implication of H(2)O(2) in the generation of RET/PTC1 rearrangement after X-ray exposure. We developed a highly specific and sensitive nested reverse transcription-PCR method. By using the human thyroid cell line HTori-3, previously found to produce RET/PTC1 after gamma-irradiation, we showed that H(2)O(2), generated during a 5 Gy X-ray irradiation, causes DNA double-strand breaks and contributes to RET/PTC1 formation. Pretreatment of cells with catalase, a scavenger of H(2)O(2), significantly decreased RET/PTC1 rearrangement formation. Finally, RET/PTC chromosomal rearrangement was detected in HTori-3.1 cells after exposure of cells to H(2)O(2) (25 micromol/L), at a dose that did not affect the cell viability. This study shows for the first time that H(2)O(2) is able to cause RET/PTC1 rearrangement in thyroid cells and consequently highlights that oxidative stress could be responsible for the occurrence of RET/PTC1 rearrangement found in thyroid lesions even in the absence of radiation exposure.
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Somodi Z, Zyuzikov NA, Kashino G, Trott KR, Prise KM. Radiation-induced genomic instability in repair deficient mutants of Chinese hamster cells. Int J Radiat Biol 2009; 81:929-36. [PMID: 16524848 DOI: 10.1080/09553000600570446] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To determine the role of single (SSB) and double strand break (DSB) repair in the induction and propagation of radiation-induced instability. MATERIALS AND METHODS Two defined hamster cell lines with known DNA repair deficiencies in DSB repair (XR-C1) and base excision repair (EM-C11) and the parental wild-type line (CHO-9) were used. The rate of micronucleus formation, apoptosis and survival were measured at 0, 7 and 14 days after X-ray radiation. RESULTS An enhanced rate of production of damaged cells was observed in wild type and the repair deficient mutants after irradiation. This was cell type, dose and time-dependent. All cells demonstrated delayed death up to day 14 after irradiation along with an elevated apoptosis frequency. The yield of micronuclei was not significantly increased in the wild-type cells, but was in the mutant cells, over the dose and time range studied. For all three endpoints the increase in damage was most pronounced in the SSB deficient cell line. CONCLUSIONS SSB and/or oxidized base damage play a major role, rather than DSB, in radiation induced instability.
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Toyokuni H, Maruo A, Suzuki K, Watanabe M. The Contribution of Radiation-Induced Large Deletion of the Genome to Chromosomal Instability. Radiat Res 2009; 171:198-203. [DOI: 10.1667/rr1464.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Miller JH, Jin S, Morgan WF, Yang A, Wan Y, Aypar U, Peters JS, Springer DL. Profiling Mitochondrial Proteins in Radiation-Induced Genome-Unstable Cell Lines with Persistent Oxidative Stress by Mass Spectrometry. Radiat Res 2008; 169:700-6. [DOI: 10.1667/rr1186.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Accepted: 02/15/2008] [Indexed: 11/03/2022]
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Gordon RY, Ignat’ev DA, Mel’nikova EV, Rogachevskii VV, Kraev IV, Khutsyan SS. Protective effect of hypothermia on brain neurons in rats exposed to ionizing radiation. Biophysics (Nagoya-shi) 2007. [DOI: 10.1134/s0006350907030165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Kim GJ, Fiskum GM, Morgan WF. A role for mitochondrial dysfunction in perpetuating radiation-induced genomic instability. Cancer Res 2006; 66:10377-83. [PMID: 17079457 PMCID: PMC2570498 DOI: 10.1158/0008-5472.can-05-3036] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Radiation-induced genomic instability (RIGI) manifests as a heritable increased rate of genetic alterations in the progeny of irradiated cells generations after the initial insult. The progeny can show an increased frequency of chromosomal translocations, deletions, mutations, micronuclei, and decreased plating efficiency. What perpetuates RIGI is unclear; however, persistently increased levels of reactive oxygen species (ROS) are frequently associated with genomically unstable clones. Furthermore, addition of free radical scavengers (e.g., DMSO, glycerol, and cationic thiol cysteamine) reduces the incidence of instability after irradiation, implicating a ROS-mediated role in RIGI induction. Because mitochondria are a major natural cellular source of ROS, we tested the hypothesis that mitochondrial dysfunction has a role in maintaining the elevated ROS levels in our irradiated, genetically unstable GM10115 Chinese hamster ovary cells. Amplex Red fluorometry measurements indicate that the relative contribution of uncoupler-sensitive mitochondrial hydrogen peroxide production to total cellular hydrogen peroxide generation is greater in unstable cells. Measurements of mitochondrial DNA levels and cell cytometric fluorescent measurements of Mitotracker Green FM indicate that differences in mitochondrial ROS production are not due to varying mitochondrial levels. However, mitochondrial respiration measured in digitonin-permeabilized cells is impaired in unstable clones. In addition, manganese superoxide dismutase, a major mitochondrial antioxidant enzyme, exhibits increased immunoreactivity but decreased enzyme activity in unstable clones, which along with decreased respiration rates may explain the increased levels of cellular ROS. These studies show that mitochondria from unstable cells are abnormal and likely contribute to the persistent oxidative stress in the unstable clones.
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Affiliation(s)
- Grace J Kim
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201-1559, USA.
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Kim GJ, Chandrasekaran K, Morgan WF. Mitochondrial dysfunction, persistently elevated levels of reactive oxygen species and radiation-induced genomic instability: a review. Mutagenesis 2006; 21:361-7. [PMID: 17065161 DOI: 10.1093/mutage/gel048] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Radiation-induced genomic instability (RIGI) challenges the long-standing notion that radiation's effects derive solely from nuclear impact. In RIGI it is the unirradiated progeny that can display phenotypic changes at delayed times after irradiation of the parental cell. RIGI might well provide the driving force behind the development of radiation-induced tumorigenesis as most cancer cells even in pre-neoplastic states display multiple genetic alterations. Thus, understanding RIGI may help elucidate the mechanisms underlying radiation-induced carcinogenesis. One characteristic of clones of genetically unstable cells is that many exhibit persistently increased levels of reactive oxygen species (ROS). Furthermore, oxidants enhance and antioxidants diminish radiation-induced instability. However, much about the mechanisms behind the initiation and perpetuation of RIGI remains unknown and we examine the evidence for the hypothesis that oxidative stress and mitochondrial dysfunction may be involved in perpetuating the unstable phenotype in some cell clones surviving ionizing radiation.
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Affiliation(s)
- Grace J Kim
- Radiation Oncology Research Laboratory, University of Maryland-Baltimore, 108 North Greene Street, BRF Room 110C, Baltimore, MD 21201, USA.
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Abstract
Exposure to ionizing radiation can induce a heritable change in the unirradiated progeny of irradiated cells. This non-targeted effect of ionizing radiation manifests as genomic instability, and although there is some debate as to the role of genomic instability in the carcinogenic process, it is thought by some to be an early step in radiation carcinogenesis. Although the mechanism of induction of genomic instability is not clearly understood, evidence suggests that secreted factors from irradiated cells may be involved. We have previously identified another non-targeted effect of ionizing radiation, the death-inducing effect. Exposure of unirradiated GM10115 cells to medium from chromosomally unstable clones was generally found to be cytotoxic. However, occasionally cells will survive in medium from unstable clones and can be clonally expanded. The absolute yield of survivors is independent of the initial number of cells plated when cell densities reached 5,000 or more cells/dish. After cytogenetic analysis of the surviving colonies, we found chromosomal instability in three of 40 clones analyzed, while some clones exhibited increased micronucleus frequency and HPRT mutation frequency. These data suggest that our chromosomally unstable GM10115 cells secrete factors that are cytotoxic to the majority of stable, parental cells but are also capable of inducing a heritable change in some of the survivors that can manifest as delayed genomic instability. These results suggest a mechanism whereby instability can be perpetuated through the influences of potentially cytotoxic factors produced by genomically unstable clones.
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Affiliation(s)
- Shruti Nagar
- Radiation Oncology Research Laboratory, University of Maryland, Baltimore, MD 21201-1559, USA
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Tominaga H, Kodama S, Matsuda N, Suzuki K, Watanabe M. Involvement of reactive oxygen species (ROS) in the induction of genetic instability by radiation. JOURNAL OF RADIATION RESEARCH 2004; 45:181-188. [PMID: 15304958 DOI: 10.1269/jrr.45.181] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Radiation generates reactive oxygen species (ROS) that interact with cellular molecules, including DNA, lipids, and proteins. To know how ROS contribute to the induction of genetic instability, we examined the effect of the anti-ROS condition, using both ascorbic acid phosphate (APM) treatment or a low oxygen condition, on the induction of delayed reproductive cell death and delayed chromosome aberrations. The primary surviving colonies of mouse m5S-derived cl. 2011-14 cells irradiated with 6 Gy of X-rays were replated and allowed to form secondary colonies. The anti-ROS treatments were applied to either preirradiation culture or postirradiation cultures for primary or secondary colony formation. Both anti-ROS conditions relieved X-ray-induced acute cell killing to a similar extent. These anti-ROS conditions also relieved genetic instability when those conditions were applied during primary colony formation. However, no effect was observed when the conditions were applied during preirradiation culture and secondary colony formation. We also demonstrated that the amounts of ROS in X-ray-irradiated cells rapidly increase and then decrease at 6 hr postirradiation, and the levels of ROS then gradually decrease to a baseline within 2 weeks. The APM treatment kept the ROS production at a lower level than an untreated control. These results suggest that the cause of genetic instability might be fixed by ROS during a 2-week postirradiation period.
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Affiliation(s)
- Hideyuki Tominaga
- Division of Radiation Biology, Department of Radiology and Radiation Biology, Graduate School of Biomedical Science, Nagasaki University, Japan
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Urushibara A, Kodama S, Suzuki K, Desa MBM, Suzuki F, Tsutsui T, Watanabe M. Involvement of telomere dysfunction in the induction of genomic instability by radiation in scid mouse cells. Biochem Biophys Res Commun 2004; 313:1037-43. [PMID: 14706647 DOI: 10.1016/j.bbrc.2003.12.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
To determine the effects of a defect in NHEJ on the induction of genomic instability by radiation, we investigated X-ray-induced delayed chromosomal aberrations such as dicentrics and fragments in scid mouse cells. We found that radiosensitive scid mouse cells are more susceptible than wild-type mouse cells to the induction of delayed chromosomal aberrations when the cells are exposed to an equivalent survival dose of X-rays. Telomere FISH analysis revealed that radiation enhances the induction of telomeric fusions where telomeric sequences remain at the fused position (tel+ end-fusions), suggesting that radiation induces telomere dysfunction. Moreover, formation of the tel+ end-fusions was found to be enhanced in scid mouse cells, suggesting that DNA-dependent protein kinase catalytic subunit (DNA-PKcs) plays a role in telomeric stabilization. Thus, the present study suggests that a cause of genomic instability is telomere dysfunction induced by radiation and that a defect in DNA-PKcs enhances the telomeric destabilization.
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Affiliation(s)
- Ayumi Urushibara
- Division of Radiation Biology, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
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Suzuki K, Ojima M, Kodama S, Watanabe M. Radiation-induced DNA damage and delayed induced genomic instability. Oncogene 2003; 22:6988-93. [PMID: 14557802 DOI: 10.1038/sj.onc.1206881] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ionizing radiation induces genomic instability, which is transmitted over many generations after irradiation through the progeny of surviving cells. Induced genomic instability is manifested as the expression of the following delayed effects: delayed reproductive death or lethal mutation, chromosomal instability, and mutagenesis. Since induced genomic instability accumulates gene mutations (actually genomic instability is the process whereby gene mutation increases subtle difference) and gross chromosomal rearrangements, it has been thought to play a role in radiation-induced carcinogenesis. Radiation-induced genomic instability exerts its effects for prolonged periods of time, suggesting the presence of a mechanism by which the initial DNA damage in the surviving cells is memorized. Recent studies have shown that such memory transmission causes delayed DNA breakage, which in turn plays a role in the induction of delayed phenotypes. Although radiation-induced genomic instability has been studied for years, many questions remain to be answered. This review summarizes the current data on radiation-induced genomic instability. In particular, the mechanism(s) involved in the initiation and perpetuation of radiation-induced genomic instability, and a role of delayed activation of p53 protein are discussed.
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Affiliation(s)
- Keiji Suzuki
- Department of Radiology and Radiation Biology, Course of Life Sciences and Radiation Research, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
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Persistent oxidative stress and gene expression changes in radiation-induced genomic instability. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0531-5131(03)01152-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Morgan WF. Non-targeted and delayed effects of exposure to ionizing radiation: I. Radiation-induced genomic instability and bystander effects in vitro. Radiat Res 2003; 159:567-80. [PMID: 12710868 DOI: 10.1667/0033-7587(2003)159[0567:nadeoe]2.0.co;2] [Citation(s) in RCA: 462] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A long-standing dogma in the radiation sciences is that energy from radiation must be deposited in the cell nucleus to elicit a biological effect. A number of non-targeted, delayed effects of ionizing radiation have been described that challenge this dogma and pose new challenges to evaluating potential hazards associated with radiation exposure. These effects include induced genomic instability and non-targeted bystander effects. The in vitro evidence for non-targeted effects in radiation biology will be reviewed, but the question as to how one extrapolates from these in vitro observations to the risk of radiation-induced adverse health effects such as cancer remains open.
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Affiliation(s)
- William F Morgan
- Radiation Oncology Research Laboratory and Greenebaum Cancer Center, Department of Radiation Oncology, University of Maryland, Baltimore, Maryland 21201-5525, USA.
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