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Unverricht-Yeboah M, Von Ameln M, Kriehuber R. Induction of Chromosomal Aberrations after Exposure to the Auger Electron Emitter Iodine-125, the β--emitter Tritium and Cesium-137 γ rays. Radiat Res 2024; 201:479-486. [PMID: 38407403 DOI: 10.1667/rade-23-00158.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 01/22/2024] [Indexed: 02/27/2024]
Abstract
High-LET-type cell survival curves have been observed in cells that were allowed to incorporate 125I-UdR into their DNA. Incorporation of tritiated thymidine into the DNA of cells has also been shown to result in an increase in relative biological effectiveness in cell survival experiments, but the increase is smaller than observed after incorporation of 125I-UdR. These findings are explained in the literature by the overall complexity of the induced DNA damage resulting from energies of the ejected electron(s) during the decay of 3H and 125I. Chromosomal aberrations (CA) are defined as morphological or structural changes of one or more chromosomes, and can be induced by ionizing radiation. Whether the number of CA is associated with the linear energy transfer (LET) of the radiation and/or the actual complexity of the induced DNA double-strand breaks (DSB) remains elusive. In this study, we investigated whether DNA lesions induced at different cell cycle stages and by different radiation types [Auger-electrons (125I), β- particles (3H), or γ radiation (137Cs)] have an impact on the number of CA induced after induction of the same number of DSB as determined by the γ-H2AX foci assay. Cells were synchronized and pulse-labeled in S phase with low activities of 125I-UdR or tritiated thymidine. For decay accumulation, cells were cryopreserved either after pulse-labeling in S phase or after progression to G2/M or G1 phase. Experiments with γ irradiation (137Cs) were performed with synchronized and cryopreserved cells in S, G2/M or G1 phase. After thawing, a CA assay was performed. All experiments were performed after a similar number of DSB were induced. CA induction after 125I-UdR was incorporated was 2.9-fold and 1.7-fold greater compared to exposure to γ radiation and radiation from incorporated tritiated thymidine, respectively, when measured in G2/M cells. In addition, measurement of CA in G2/M cells after incorporation of 125I-UdR was 2.5-fold greater when compared to cells in G1 phase. In contrast, no differences were observed between the three radiation qualities with respect to exposure after cryopreservation in S or G1 phase. The data indicate that the 3D organization of replicated DNA in G2/M cells seems to be more sensitive to induction of more complex DNA lesions compared to the DNA architecture in S or G1 cells. Whether this is due to the DNA organization itself or differences in DNA repair capability remains unclear.
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Affiliation(s)
- M Unverricht-Yeboah
- Forschungszentrum Jülich, Department of Safety and Radiation Protection, Jülich, Germany
| | - M Von Ameln
- Forschungszentrum Jülich, Department of Safety and Radiation Protection, Jülich, Germany
| | - R Kriehuber
- Forschungszentrum Jülich, Department of Safety and Radiation Protection, Jülich, Germany
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da Costa Siqueira JT, Reis AC, Lopes JML, Ladeira LO, Viccini LF, de Mello Brandão H, Munk M, de Sousa SM. Chromosomal aberrations and changes in the methylation patterns of Lactuca sativa L. (Asteraceae) exposed to carbon nanotubes. Biologia (Bratisl) 2023. [DOI: 10.1007/s11756-023-01325-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Nikolakopoulou A, Soni A, Habibi M, Karaiskos P, Pantelias G, Terzoudi GI, Iliakis G. G2/M Checkpoint Abrogation With Selective Inhibitors Results in Increased Chromatid Breaks and Radiosensitization of 82-6 hTERT and RPE Human Cells. Front Public Health 2021; 9:675095. [PMID: 34123995 PMCID: PMC8193504 DOI: 10.3389/fpubh.2021.675095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 04/26/2021] [Indexed: 11/13/2022] Open
Abstract
While technological advances in radiation oncology have led to a more precise delivery of radiation dose and a decreased risk of side effects, there is still a need to better understand the mechanisms underlying DNA damage response (DDR) at the DNA and cytogenetic levels, and to overcome tumor resistance. To maintain genomic stability, cells have developed sophisticated signaling pathways enabling cell cycle arrest to facilitate DNA repair via the DDR-related kinases and their downstream targets, so that DNA damage or DNA replication stress induced by genotoxic therapies can be resolved. ATM, ATR, and Chk1 kinases are key mediators in DDR activation and crucial factors in treatment resistance. It is of importance, therefore, as an alternative to the conventional clonogenic assay, to establish a cytogenetic assay enabling reliable and time-efficient results in evaluating the potency of DDR inhibitors for radiosensitization. Toward this goal, the present study aims at the development and optimization of a chromosomal radiosensitivity assay using the DDR and G2-checkpoint inhibitors as a novel modification compared to the classical G2-assay. Also, it aims at investigating the strengths of this assay for rapid radiosensitivity assessments in cultured cells, and potentially, in tumor cells obtained from biopsies. Specifically, exponentially growing RPE and 82-6 hTERT human cells are irradiated during the G2/M-phase transition in the presence or absence of Caffeine, VE-821, and UCN-1 inhibitors of ATM/ATR, ATR, and Chk1, respectively, and the induced chromatid breaks are used to evaluate cell radiosensitivity and their potency for radiosensitization. The increased yield of chromatid breaks in the presence of DDR inhibitors, which underpins radiosensitization, is similar to that observed in cells from highly radiosensitive AT-patients, and is considered here as 100% radiosensitive internal control. The results highlight the potential of our modified G2-assay using VE-821 to evaluate cell radiosensitivity, the efficacy of DDR inhibitors in radiosensitization, and reinforce the concept that ATM, ATR, and Chk1 represent attractive anticancer drug targets in radiation oncology.
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Affiliation(s)
- Aggeliki Nikolakopoulou
- Laboratory of Health Physics, Radiobiology and Cytogenetics, Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, National Centre for Scientific Research "Demokritos", Athens, Greece.,Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Aashish Soni
- Institute of Medical Radiation Biology, Medical School, University of Duisburg-Essen, Essen, Germany
| | - Martha Habibi
- Laboratory of Health Physics, Radiobiology and Cytogenetics, Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, National Centre for Scientific Research "Demokritos", Athens, Greece.,Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Pantelis Karaiskos
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Gabriel Pantelias
- Laboratory of Health Physics, Radiobiology and Cytogenetics, Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, National Centre for Scientific Research "Demokritos", Athens, Greece
| | - Georgia I Terzoudi
- Laboratory of Health Physics, Radiobiology and Cytogenetics, Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, National Centre for Scientific Research "Demokritos", Athens, Greece
| | - George Iliakis
- Institute of Medical Radiation Biology, Medical School, University of Duisburg-Essen, Essen, Germany
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Investigation of DNA Damage and Cell-Cycle Distribution in Human Peripheral Blood Lymphocytes under Exposure to High Doses of Proton Radiotherapy. BIOLOGY 2021; 10:biology10020111. [PMID: 33546318 PMCID: PMC7913503 DOI: 10.3390/biology10020111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 01/29/2021] [Accepted: 01/31/2021] [Indexed: 12/13/2022]
Abstract
This study systematically investigates how a single high-dose therapeutic proton beam versus X-rays influences cell-cycle phase distribution and DNA damage in human peripheral blood lymphocytes (HPBLs). Blood samples from ten volunteers (both male and female) were irradiated with doses of 8.00, 13.64, 15.00, and 20.00 Gy of 250 kV X-rays or 60 MeV protons. The dose-effect relations were calculated and distributed by plotting the frequencies of DNA damage of excess Premature Chromosome Condensation (PCC) fragments and rings in the G2/M phase, obtained via chemical induction with calyculin A. The Papworth's u test was used to evaluate the distribution of DNA damage. The study shows that high doses of protons induce HPBL DNA damage in the G2/M phase differently than X-rays do. The results indicate a different distribution of DNA damage following high doses of irradiation with protons versus photons between donors, types of radiation, and doses. The proliferation index confirms the impact of high doses of mitosis and the influence of radiotherapy type on the different HPBL response. The results illuminate the cellular and molecular mechanisms that underlie differences in the distribution of DNA damage and cell-cycle phases; these findings may yield an improvement in the efficacy of the radiotherapies used.
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Jagetia GC, Jacob PS. (E)4-[4-N,N-dimethylaminophenyl]but-3-en-2-one mitigates radiation-induced chromosome damage in BALB/c mouse bone marrow. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2020; 858-860:503238. [PMID: 33198928 DOI: 10.1016/j.mrgentox.2020.503238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/04/2020] [Accepted: 08/06/2020] [Indexed: 11/29/2022]
Abstract
We examined the effects of administration of (E) 4-[4-N,N-dimethylaminophenyl]but-3-en-2-one (DMAP) on radiation-induced chromosome damage in mice. Mice were whole-body exposed to γ-rays, 0-4 Gy, and then immediately administered DMAP, 20 mg/kg. After 24 h, mice were sacrificed, femora were removed, marrow was extracted, and chromosome aberrations were scored in the bone marrow cells. With vehicle-only (saline or oil) treatment, radiation dose-dependent damage was seen in aberrant cells, chromosome breaks, chromatid breaks, centric rings, di-, tri-, and tetracentrics, acentric fragments, total aberrations, polyploidy, and pulverization. Post-administration of DMAP was protective as it reduced chromosome damage. DMAP treatment may be a useful protective agent following radiation accidents or radiotherapy.
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Affiliation(s)
| | - Preenu Sunil Jacob
- Latifa Hospital, Oud Metha Road, Al Jaddaf, Dubai, United Arab Emirates.
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Pantelias A, Karachristou I, Georgakilas AG, Terzoudi GI. Interphase Cytogenetic Analysis of Micronucleated and Multinucleated Cells Supports the Premature Chromosome Condensation Hypothesis as the Mechanistic Origin of Chromothripsis. Cancers (Basel) 2019; 11:E1123. [PMID: 31390832 PMCID: PMC6721583 DOI: 10.3390/cancers11081123] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/26/2019] [Accepted: 08/03/2019] [Indexed: 12/19/2022] Open
Abstract
The discovery of chromothripsis in cancer genomes challenges the long-standing concept of carcinogenesis as the result of progressive genetic events. Despite recent advances in describing chromothripsis, its mechanistic origin remains elusive. The prevailing conception is that it arises from a massive accumulation of fragmented DNA inside micronuclei (MN), whose defective nuclear envelope ruptures or leads to aberrant DNA replication, before main nuclei enter mitosis. An alternative hypothesis is that the premature chromosome condensation (PCC) dynamics in asynchronous micronucleated cells underlie chromosome shattering in a single catastrophic event, a hallmark of chromothripsis. Specifically, when main nuclei enter mitosis, premature chromatin condensation provokes the shattering of chromosomes entrapped inside MN, if they are still undergoing DNA replication. To test this hypothesis, the agent RO-3306, a selective ATP-competitive inhibitor of CDK1 that promotes cell cycle arrest at the G2/M boundary, was used in this study to control the degree of cell cycle asynchrony between main nuclei and MN. By delaying the entrance of main nuclei into mitosis, additional time was allowed for the completion of DNA replication and duplication of chromosomes inside MN. We performed interphase cytogenetic analysis using asynchronous micronucleated cells generated by exposure of human lymphocytes to γ-rays, and heterophasic multinucleated Chinese hamster ovary (CHO) cells generated by cell fusion procedures. Our results demonstrate that the PCC dynamics during asynchronous mitosis in micronucleated or multinucleated cells are an important determinant of chromosome shattering and may underlie the mechanistic origin of chromothripsis.
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Affiliation(s)
- Antonio Pantelias
- Laboratory of Health Physics, Radiobiology & Cytogenetics, Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Centre for Scientific Research "Demokritos", 15341 Agia Paraskevi, Greece.
- DNA Damage Laboratory, Physics Department, School of Mathematical and Physical Sciences, National Technical University of Athens (NTUA), 15780 Zografou, Greece.
| | - Ioanna Karachristou
- Laboratory of Health Physics, Radiobiology & Cytogenetics, Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Centre for Scientific Research "Demokritos", 15341 Agia Paraskevi, Greece
| | - Alexandros G Georgakilas
- DNA Damage Laboratory, Physics Department, School of Mathematical and Physical Sciences, National Technical University of Athens (NTUA), 15780 Zografou, Greece
| | - Georgia I Terzoudi
- Laboratory of Health Physics, Radiobiology & Cytogenetics, Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Centre for Scientific Research "Demokritos", 15341 Agia Paraskevi, Greece.
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dos Santos R, Vicari T, Santos SA, Felisbino K, Mattoso N, Sant’Anna-Santos BF, Cestari MM, Leme DM. Genotoxicity of titanium dioxide nanoparticles and triggering of defense mechanisms in Allium cepa. Genet Mol Biol 2019; 42:425-435. [PMID: 31259365 PMCID: PMC6726158 DOI: 10.1590/1678-4685-gmb-2018-0205] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 11/05/2018] [Indexed: 01/20/2023] Open
Abstract
Titanium dioxide nanoparticles (TiO2NPs) are widely used and may impact the environment. Thus, this study used a high concentration of TiO2NP (1000 mg/L) to verify the defense mechanisms triggered by a plant system - an indicator of toxicity. Furthermore, this study aimed at completely characterizing TiO2NP suspensions to elucidate their toxic behavior. TiO2NPs were taken up by meristematic cells of Allium cepa, leading to slight inhibition of seed germination and root growth. However, severe cellular and DNA damages were observed in a concentration-dependent manner (10, 100, and 1000 mg/L). For this reason, we used the highest tested concentration (1000 mg/L) to verify if the plant cells developed defense mechanisms against the TiO2NPs and evaluated other evidences of TiO2NP genotoxicity. Nucleolar alterations and plant defense responses (i.e., increased lytic vacuoles, oil bodies and NP phase change) were observed in meristematic cells exposed to TiO2NP at 1000 mg/L. In summary, TiO2NPs can damage the genetic material of plants; however, plants displayed defense mechanisms against the deleterious effects of these NPs. In addition, A. cepa was found to be a suitable test system to evaluate the cyto- and genotoxicity of NPs.
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Affiliation(s)
- Ronaldo dos Santos
- Department of Genetics, Universidade Federal do Paraná (UFPR),
Curitiba, PR, Brazil
| | - Taynah Vicari
- Department of Genetics, Universidade Federal do Paraná (UFPR),
Curitiba, PR, Brazil
| | - Samuel A. Santos
- Department of Plant Pathology, Universidade Federal de Viçosa
(UFV), Viçosa, MG, Brazil
| | - Karoline Felisbino
- Department of Genetics, Universidade Federal do Paraná (UFPR),
Curitiba, PR, Brazil
| | - Ney Mattoso
- Department of Physics, Universidade Federal do Paraná (UFPR),
Curitiba, PR, Brazil
| | | | | | - Daniela Morais Leme
- Department of Genetics, Universidade Federal do Paraná (UFPR),
Curitiba, PR, Brazil
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8
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Modulation of chromatin conformation by the histone deacetylase inhibitor trichostatin A promotes the removal of radiation-induced lesions in ataxia telangiectasia cell lines. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2018; 836:109-116. [DOI: 10.1016/j.mrgentox.2018.06.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 06/07/2018] [Accepted: 06/07/2018] [Indexed: 11/19/2022]
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9
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Rodriguez-Berriguete G, Granata G, Puliyadi R, Tiwana G, Prevo R, Wilson RS, Yu S, Buffa F, Humphrey TC, McKenna WG, Higgins GS. Nucleoporin 54 contributes to homologous recombination repair and post-replicative DNA integrity. Nucleic Acids Res 2018; 46:7731-7746. [PMID: 29986057 PMCID: PMC6125679 DOI: 10.1093/nar/gky569] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 05/25/2018] [Accepted: 06/14/2018] [Indexed: 12/21/2022] Open
Abstract
The nuclear pore complex (NPC) machinery is emerging as an important determinant in the maintenance of genome integrity and sensitivity to DNA double-strand break (DSB)-inducing agents, such as ionising radiation (IR). In this study, using a high-throughput siRNA screen, we identified the central channel NPC protein Nup54, and concomitantly its molecular partners Nup62 and Nup58, as novel factors implicated in radiosensitivity. Nup54 depletion caused an increase in cell death by mitotic catastrophe after IR, and specifically enhanced both the duration of the G2 arrest and the radiosensitivity of cells that contained replicated DNA at the time of IR exposure. Nup54-depleted cells also exhibited increased formation of chromosome aberrations arisen from replicated DNA. Interestingly, we found that Nup54 is epistatic with the homologous recombination (HR) factor Rad51. Moreover, using specific DNA damage repair reporters, we observed a decreased HR repair activity upon Nup54 knockdown. In agreement with a role in HR repair, we also demonstrated a decreased formation of HR-linked DNA synthesis foci and sister chromatid exchanges after IR in cells depleted of Nup54. Our study reveals a novel role for Nup54 in the response to IR and the maintenance of HR-mediated genome integrity.
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Affiliation(s)
- Gonzalo Rodriguez-Berriguete
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Giovanna Granata
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Rathi Puliyadi
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Gaganpreet Tiwana
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Remko Prevo
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Rhodri S Wilson
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Sheng Yu
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Francesca Buffa
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Timothy C Humphrey
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - W Gillies McKenna
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Geoff S Higgins
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
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Bakhoum SF, Kabeche L, Compton DA, Powell SN, Bastians H. Mitotic DNA Damage Response: At the Crossroads of Structural and Numerical Cancer Chromosome Instabilities. Trends Cancer 2017; 3:225-234. [PMID: 28718433 DOI: 10.1016/j.trecan.2017.02.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/04/2017] [Accepted: 02/06/2017] [Indexed: 11/29/2022]
Abstract
DNA double-strand breaks (DSBs) prevent cells from entering mitosis allowing cells to repair their genomic damage. Little is known about the response to DSBs once cells have already committed to mitosis. Here, we review the genome-protective role of the mitotic DNA damage response (DDR) and evidence suggesting that its untimely activation induces chromosome segregation errors and paradoxically undermines genomic integrity. In contrast to normal cells, cancer cells coopt this pathway to propagate structural and numerical chromosomal instabilities. Cells derived from genomically unstable tumors exhibit evidence for a partially activated DDR during mitosis, which leads to ongoing chromosome segregation errors. Thus, a thorough understanding of the consequences of mitotic DNA damage is key to our ability to devise novel anticancer therapeutic strategies.
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Affiliation(s)
- Samuel F Bakhoum
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
| | - Lilian Kabeche
- Massachusetts General Hospital Cancer Center, Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
| | - Duane A Compton
- Department of Biochemistry and the Norris-Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Simon N Powell
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Holger Bastians
- Institute of Molecular Oncology, Section for Cellular Oncology, Goettingen Center for Molecular Biosciences (GZMB) and University Medical Center, University of Göttingen, D-37077 Goettingen, Germany
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Low concentrations of caffeine induce asymmetric cell division as observed in vitro by means of the CBMN-assay and iFISH. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 793:71-8. [DOI: 10.1016/j.mrgentox.2015.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 08/03/2015] [Indexed: 11/20/2022]
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12
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Çelik S, Li Y, O’Neill C. The effect of DNA damage on the pattern of immune-detectable DNA methylation in mouse embryonic fibroblasts. Exp Cell Res 2015; 339:20-34. [DOI: 10.1016/j.yexcr.2015.08.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 07/31/2015] [Accepted: 08/27/2015] [Indexed: 12/21/2022]
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13
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Schmitz S, Oskamp D, Pomplun E, Kriehuber R. Chromosome aberrations induced by the Auger electron emitter 125I. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 793:64-70. [DOI: 10.1016/j.mrgentox.2015.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 08/19/2015] [Indexed: 10/23/2022]
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14
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Venkatesan S, Natarajan AT, Hande MP. Chromosomal instability--mechanisms and consequences. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 793:176-84. [PMID: 26520388 DOI: 10.1016/j.mrgentox.2015.08.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 08/21/2015] [Indexed: 01/08/2023]
Abstract
Chromosomal instability is defined as a state of numerical and/or structural chromosomal anomalies in cells. Numerous studies have documented the incidence of chromosomal instability, which acutely or chronically may lead to accelerated ageing (tissue-wide or even organismal), cancer or other genetic disorders. Potential mechanisms leading to the generation of chromosome-genome instability include erroneous/inefficient DNA repair, chromosome segregation defects, spindle assembly defects, DNA replication stress, telomere shortening/dysfunction - to name a few. Understanding the cellular and molecular mechanisms for chromosomal instability in various human cells and tissues will be useful in elucidating the cause for many age associated diseases including cancer. This approach holds a great promise for the cytogenetic assays not only for prognosis but also for diagnostic purposes in clinical settings. In this review, a multi-dimensional approach has been attempted to portray the complexity behind the incidence of chromosome-genome instability including evolutionary implications at the species level for some of the mechanisms of chromosomal instability.
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Affiliation(s)
- Shriram Venkatesan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597
| | - Adayapalam T Natarajan
- Department of Ecological and Biological Sciences, University of Tuscia, Viterbo 01100, Italy
| | - M Prakash Hande
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597; Tembusu College, National University of Singapore, Singapore, 138597.
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15
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Carante MP, Altieri S, Bortolussi S, Postuma I, Protti N, Ballarini F. Modeling radiation-induced cell death: role of different levels of DNA damage clustering. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2015; 54:305-316. [PMID: 25956821 DOI: 10.1007/s00411-015-0601-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 04/28/2015] [Indexed: 06/04/2023]
Abstract
Some open questions on the mechanisms underlying radiation-induced cell death were addressed by a biophysical model, focusing on DNA damage clustering and its consequences. DNA "cluster lesions" (CLs) were assumed to produce independent chromosome fragments that, if created within a micrometer-scale threshold distance (d), can lead to chromosome aberrations following mis-rejoining; in turn, certain aberrations (dicentrics, rings and large deletions) were assumed to lead to clonogenic cell death. The CL yield and d were the only adjustable parameters. The model, implemented as a Monte Carlo code called BIophysical ANalysis of Cell death and chromosome Aberrations (BIANCA), provided simulated survival curves that were directly compared with experimental data on human and hamster cells exposed to photons, protons, α-particles and heavier ions including carbon and iron. d = 5 μm, independent of radiation quality, and CL yields in the range ~2-20 CLs Gy(-1) cell(-1), depending on particle type and energy, led to good agreement between simulations and data. This supports the hypothesis of a pivotal role of DNA cluster damage at sub-micrometric scale, modulated by chromosome fragment mis-rejoining at micrometric scale. To investigate the features of such critical damage, the CL yields were compared with experimental or theoretical yields of DNA fragments of different sizes, focusing on the base-pair scale (related to the so-called local clustering), the kbp scale ("regional clustering") and the Mbp scale, corresponding to chromatin loops. Interestingly, the CL yields showed better agreement with kbp fragments rather than bp fragments or Mbp fragments; this suggests that also regional clustering, in addition to other clustering levels, may play an important role, possibly due to its relationship with nucleosome organization in the chromatin fiber.
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Affiliation(s)
- M P Carante
- Physics Department, University of Pavia, Via Bassi 6, 27100, Pavia, Italy
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16
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Detection and Automated Scoring of Dicentric Chromosomes in Nonstimulated Lymphocyte Prematurely Condensed Chromosomes After Telomere and Centromere Staining. Int J Radiat Oncol Biol Phys 2015; 91:640-9. [DOI: 10.1016/j.ijrobp.2014.10.048] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 09/27/2014] [Accepted: 10/24/2014] [Indexed: 12/24/2022]
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17
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Rybaczek D. Ultrastructural changes associated with the induction of premature chromosome condensation in Vicia faba root meristem cells. PLANT CELL REPORTS 2014; 33:1547-1564. [PMID: 24898011 PMCID: PMC4133037 DOI: 10.1007/s00299-014-1637-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 05/15/2014] [Accepted: 05/19/2014] [Indexed: 06/03/2023]
Abstract
PCC induction is regulated by several signaling pathways, and all observed effects associated with PCC induction are strongly dependent on the mechanism of action of each PCC inducer used. Electron microscopic observations of cells with symptoms of premature chromosome condensation (PCC) showed that the interphase chromatin and mitotic chromosomes differed with respect to a chemical compound inducing PCC. Induction of this process under the influence of hydroxyurea and caffeine as well as hydroxyurea and sodium metavanadate led to a slight decrease in interphase chromatin condensation and the formation of chromosomes with a considerably loosened structure in comparison with the control. Incubation in the mixture of hydroxyurea and 2-aminopurine brought about clear chromatin dispersion in interphase and very strong mitotic chromosome condensation. Electron microscopic examinations also revealed the characteristic features of the structural organization of cytoplasm of Vicia faba root meristems, which seemed to be dependent on the type of the PCC inducer used. The presence of the following was observed: (i) large plastids filled with starch grains (caffeine), (ii) mitochondria and plastids of electron dense matrix with dilated invaginations of their internal membranes (2-aminopurine), and (iii) large mitochondria of electron clear matrix and plastids containing protein crystals in their interior (sodium metavanadate). Moreover, since caffeine causes either the most effective loosening of chromatin fibrils (within the prematurely condensed chromosomes) or induction of starch formation (in the plastids surrounding the nuclei), this may be a proof that demonstrates the existence of a link between physical accessibility to chromatin and the effectiveness of cellular signaling (e.g., phosphothreonine-connected).
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Affiliation(s)
- Dorota Rybaczek
- Department of Cytophysiology, Institute of Experimental Biology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236, Lodz, Poland,
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18
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Sebastià N, Montoro A, Hervás D, Pantelias G, Hatzi VI, Soriano JM, Villaescusa JI, Terzoudi GI. Curcumin and trans-resveratrol exert cell cycle-dependent radioprotective or radiosensitizing effects as elucidated by the PCC and G2-assay. Mutat Res 2014; 766-767:49-55. [PMID: 25847272 DOI: 10.1016/j.mrfmmm.2014.05.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 05/14/2014] [Accepted: 05/27/2014] [Indexed: 06/04/2023]
Abstract
Curcumin and trans-resveratrol are well-known antioxidant polyphenols with radiomodulatory properties, radioprotecting non-cancerous cells while radiosensitizing tumor cells. This dual action may be the result of their radical scavenging properties and their effects on cell-cycle checkpoints that are activated in response to radiation-induced chromosomal damage. It could be also caused by their effect on regulatory pathways with impact on detoxification enzymes, the up-regulation of endogenous protective systems, and cell-cycle-dependent processes of DNA damage. This work aims to elucidate the mechanisms underlying the dual action of these polyphenols and investigates under which conditions they exhibit radioprotecting or radiosensitizing properties. The peripheral blood lymphocyte test system was used, applying concentrations ranging from 1.4 to 140μM curcumin and 2.2 to 220μM trans-resveratrol. The experimental design focuses first on their radioprotective effects in non-cycling lymphocytes, as uniquely visualized using cell fusion-mediated premature chromosome condensation, excluding, thus, cell-cycle interference to repair processes and activation of checkpoints. Second, the radiosensitizing potential of these chemicals on the induction of chromatid breaks in cultured lymphocytes following G2-phase irradiation was evaluated by a standardized G2-chromosomal radiosensitivity predictive assay. This assay uses caffeine for G2-checkpoint abrogation and it was applied to obtain an internal control for radiosensitivity testing, which simulates conditions similar to those of the highly radiosensitive lymphocytes of AT patients. The results demonstrate for the first time the cell-cycle-dependent action of these polyphenols. When non-cycling cells are irradiated, the radioprotective properties of curcumin and trans-resveratrol are more prominent. However, when cycling cells are irradiated during G2-phase, the radiosensitizing features of these compounds are more pronounced. This observation offers a new biological basis for the mechanisms underlying the action of these polyphenols in cancer radiotherapy.
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Affiliation(s)
- N Sebastià
- Radiation Protection Service, IIS La Fe, Health Research Institute La Fe, Valencia, Spain.
| | - A Montoro
- Radiation Protection Service, Universitary and Politechnic Hospital La Fe, Valencia, Spain; Grupo de Investigación Biomédica en Imagen GIBI230, IIS La Fe, Health Research Institute La Fe, Valencia, Spain; Unidad Mixta de Investigación en Endocrinología, Nutrición y Dietética Clínica, IIS La Fe, Health Research Institute La Fe, Valencia, Spain
| | - D Hervás
- Biostatistics Unit, IIS La Fe, Health Research Institute La Fe, Valencia, Spain
| | - G Pantelias
- Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Centre for Scientific Research "Demokritos", Aghia Paraskevi, Athens, Greece
| | - V I Hatzi
- Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Centre for Scientific Research "Demokritos", Aghia Paraskevi, Athens, Greece
| | - J M Soriano
- Grupo de Investigación Biomédica en Imagen GIBI230, IIS La Fe, Health Research Institute La Fe, Valencia, Spain; Unidad Mixta de Investigación en Endocrinología, Nutrición y Dietética Clínica, IIS La Fe, Health Research Institute La Fe, Valencia, Spain; Department of Preventive Medicine and Public Health, Faculty of Pharmacy, University of Valencia, Burjassot, Valencia, Spain
| | - J I Villaescusa
- Radiation Protection Service, Universitary and Politechnic Hospital La Fe, Valencia, Spain
| | - G I Terzoudi
- Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Centre for Scientific Research "Demokritos", Aghia Paraskevi, Athens, Greece
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19
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Kong Q, Xie B, Li J, Huan Y, Huang T, Wei R, Lv J, Liu S, Liu Z. Identification and characterization of an oocyte factor required for porcine nuclear reprogramming. J Biol Chem 2014; 289:6960-6968. [PMID: 24474691 PMCID: PMC3945357 DOI: 10.1074/jbc.m113.543793] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 01/26/2014] [Indexed: 01/15/2023] Open
Abstract
Nuclear reprogramming of somatic cells can be induced by oocyte factors. Despite numerous attempts, the factors responsible for successful nuclear reprogramming remain elusive. In the present study, we found that porcine oocytes with the first polar body collected at 42 h of in vitro maturation had a stronger ability to support early development of cloned embryos than porcine oocytes with the first polar body collected at 33 h of in vitro maturation. To explore the key reprogramming factors responsible for the difference, we compared proteome signatures of the two groups of oocytes. 18 differentially expressed proteins between these two groups of oocytes were discovered by mass spectrometry (MS). Among these proteins, we especially focused on vimentin (VIM). A certain amount of VIM protein was stored in oocytes and accumulated during oocyte maturation, and maternal VIM was specifically incorporated into transferred somatic nuclei during nuclear reprogramming. When maternal VIM function was inhibited by anti-VIM antibody, the rate of cloned embryos developing to blastocysts was significantly lower than that of IgG antibody-injected embryos and non-injected embryos (12.24 versus 22.57 and 21.10%; p < 0.05), but the development of in vitro fertilization and parthenogenetic activation embryos was not affected. Furthermore, we found that DNA double strand breaks dramatically increased and that the p53 pathway was activated in cloned embryos when VIM function was inhibited. This study demonstrates that maternal VIM, as a genomic protector, is crucial for nuclear reprogramming in porcine cloned embryos.
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Affiliation(s)
- Qingran Kong
- Laboratory of Embryo Biotechnology, College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Bingteng Xie
- Laboratory of Embryo Biotechnology, College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Jingyu Li
- Laboratory of Embryo Biotechnology, College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Yanjun Huan
- Laboratory of Embryo Biotechnology, College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Tianqing Huang
- Laboratory of Embryo Biotechnology, College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Renyue Wei
- Laboratory of Embryo Biotechnology, College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Jiawei Lv
- Laboratory of Embryo Biotechnology, College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Shichao Liu
- Laboratory of Embryo Biotechnology, College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Zhonghua Liu
- Laboratory of Embryo Biotechnology, College of Life Science, Northeast Agricultural University, Harbin 150030, China.
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20
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Rapid assessment of high-dose radiation exposures through scoring of cell-fusion-induced premature chromosome condensation and ring chromosomes. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2013; 757:45-51. [DOI: 10.1016/j.mrgentox.2013.06.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 04/10/2013] [Accepted: 04/15/2013] [Indexed: 11/23/2022]
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21
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Friedland W, Kundrát P. Track structure based modelling of chromosome aberrations after photon and alpha-particle irradiation. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2013; 756:213-23. [DOI: 10.1016/j.mrgentox.2013.06.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 06/18/2013] [Indexed: 02/01/2023]
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22
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Liu C, Kawata T, Furusawa Y, Zhou G, Inoue K, Fukada J, Kota R, George K, Cucinotta F, Okayasu R. Chromosome aberrations in normal human fibroblasts analyzed in G0/G1 and G2/M phases after exposure in G0 to radiation with different linear energy transfer (LET). MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2013; 756:101-7. [DOI: 10.1016/j.mrgentox.2013.05.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 05/09/2013] [Indexed: 11/29/2022]
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23
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Schipler A, Iliakis G. DNA double-strand-break complexity levels and their possible contributions to the probability for error-prone processing and repair pathway choice. Nucleic Acids Res 2013; 41:7589-605. [PMID: 23804754 PMCID: PMC3763544 DOI: 10.1093/nar/gkt556] [Citation(s) in RCA: 203] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Although the DNA double-strand break (DSB) is defined as a rupture in the double-stranded DNA molecule that can occur without chemical modification in any of the constituent building blocks, it is recognized that this form is restricted to enzyme-induced DSBs. DSBs generated by physical or chemical agents can include at the break site a spectrum of base alterations (lesions). The nature and number of such chemical alterations define the complexity of the DSB and are considered putative determinants for repair pathway choice and the probability that errors will occur during this processing. As the pathways engaged in DSB processing show distinct and frequently inherent propensities for errors, pathway choice also defines the error-levels cells opt to accept. Here, we present a classification of DSBs on the basis of increasing complexity and discuss how complexity may affect processing, as well as how it may cause lethal or carcinogenic processing errors. By critically analyzing the characteristics of DSB repair pathways, we suggest that all repair pathways can in principle remove lesions clustering at the DSB but are likely to fail when they encounter clusters of DSBs that cause a local form of chromothripsis. In the same framework, we also analyze the rational of DSB repair pathway choice.
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Affiliation(s)
- Agnes Schipler
- Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, 45122 Essen, Germany
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24
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Kuffler DP. Hyperbaric oxygen therapy: can it prevent irradiation-induced necrosis? Exp Neurol 2012; 235:517-27. [PMID: 22465460 DOI: 10.1016/j.expneurol.2012.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 02/27/2012] [Accepted: 03/17/2012] [Indexed: 10/28/2022]
Abstract
Radiosurgery is an important non-invasive procedure for the treatment of tumors and vascular malformations. However, in addition to killing target tissues, cranial irradiation induces damage to adjacent healthy tissues leading to neurological deterioration in both pediatric and adult patients, which is poorly understood and insufficiently treatable. To minimize irradiation damage to healthy tissue, not the optimal therapeutic irradiation dose required to eliminate the target lesion is used but lower doses. Although the success rate of irradiation surgery is about 95%, 5% of patients suffer problems, most commonly neurological, that are thought to be a direct consequence of irradiation-induced inflammation. Although no direct correlation has been demonstrated, the appearance and disappearance of inflammation that develops following irradiation commonly parallel the appearance and disappearance of neurological side effects that are associated with the neurological function of the irradiated brain regions. These observations have led to the hypothesis that brain inflammation is causally related to the observed neurological side effects. Studies indicate that hyperbaric oxygen therapy (HBOT) applied after the appearance of irradiation-induced neurological side effects reduces the incidence and severity of those side effects. This may result from HBOT reducing inflammation, promoting angiogenesis, and influencing other cellular functions thereby suppressing events that cause the neurological side effects. However, it would be significantly better for the patient if rather than waiting for neurological side effects to become manifest they could be avoided. This review examines irradiation-induced neurological side effects, methods that minimize or resolve those side effects, and concludes with a discussion of whether HBOT applied following irradiation, but before manifestation of neurological side effects may prevent or reduce the appearance of irradiation-induced neurological side effects.
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Affiliation(s)
- Damien P Kuffler
- Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, Puerto Rico.
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25
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Mozdarani H. Biological complexities in radiation carcinogenesis and cancer radiotherapy: impact of new biological paradigms. Genes (Basel) 2012; 3:90-114. [PMID: 24704845 PMCID: PMC3899963 DOI: 10.3390/genes3010090] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 01/07/2012] [Accepted: 01/13/2012] [Indexed: 12/31/2022] Open
Abstract
Although radiation carcinogenesis has been shown both experimentally and epidemiologically, the use of ionizing radiation is also one of the major modalities in cancer treatment. Various known cellular and molecular events are involved in carcinogenesis. Apart from the known phenomena, there could be implications for carcinogenesis and cancer prevention due to other biological processes such as the bystander effect, the abscopal effect, intrinsic radiosensitivity and radioadaptation. Bystander effects have consequences for mutation initiated cancer paradigms of radiation carcinogenesis, which provide the mechanistic justification for low-dose risk estimates. The abscopal effect is potentially important for tumor control and is mediated through cytokines and/or the immune system (mainly cell-mediated immunity). It results from loss of growth and stimulatory and/or immunosuppressive factors from the tumor. Intrinsic radiosensitivity is a feature of some cancer prone chromosomal breakage syndromes such as ataxia telangectiasia. Radiosensitivity is manifested as higher chromosomal aberrations and DNA repair impairment is now known as a good biomarker for breast cancer screening and prediction of prognosis. However, it is not yet known whether this effect is good or bad for those receiving radiation or radiomimetic agents for treatment. Radiation hormesis is another major concern for carcinogenesis. This process which protects cells from higher doses of radiation or radio mimic chemicals, may lead to the escape of cells from mitotic death or apoptosis and put cells with a lower amount of damage into the process of cancer induction. Therefore, any of these biological phenomena could have impact on another process giving rise to genome instability of cells which are not in the field of radiation but still receiving a lower amount of radiation. For prevention of radiation induced carcinogenesis or risk assessment as well as for successful radiation therapy, all these phenomena should be taken into account.
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Affiliation(s)
- Hossein Mozdarani
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran P.O. Box 14115-111, Iran.
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26
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Aziz K, Nowsheen S, Pantelias G, Iliakis G, Gorgoulis VG, Georgakilas AG. Targeting DNA damage and repair: embracing the pharmacological era for successful cancer therapy. Pharmacol Ther 2011; 133:334-50. [PMID: 22197993 DOI: 10.1016/j.pharmthera.2011.11.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 11/30/2011] [Indexed: 12/19/2022]
Abstract
DNA is under constant assault from genotoxic agents which creates different kinds of DNA damage. The precise replication of the genome and the continuous surveillance of its integrity are critical for survival and the avoidance of carcinogenesis. Cells have evolved an arsenal of repair pathways and cell cycle checkpoints to detect and repair DNA damage. When repair fails, typically cell cycle progression is halted and apoptosis is initiated. Here, we review the different sources and types of DNA damage including DNA replication stress and oxidative stress, the repair pathways that cells utilize to repair damaged DNA, and discuss their biological significance, especially with reference to cancer induction and cancer therapy. We also describe the main methodologies currently used for the detection of DNA damage with their strengths and limitations. We conclude with an outline as to how this information can be used to identify novel pharmacological targets for DNA repair pathways or enhancers of DNA damage to develop improved treatment strategies that will benefit cancer patients.
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Affiliation(s)
- K Aziz
- Department of Radiation Oncology & Molecular Radiation Sciences, Johns Hopkins School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD 21231, USA
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27
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A standardized G2-assay for the prediction of individual radiosensitivity. Radiother Oncol 2011; 101:28-34. [DOI: 10.1016/j.radonc.2011.09.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 09/16/2011] [Accepted: 09/29/2011] [Indexed: 11/21/2022]
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28
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Bogomazova AN, Lagarkova MA, Tskhovrebova LV, Shutova MV, Kiselev SL. Error-prone nonhomologous end joining repair operates in human pluripotent stem cells during late G2. Aging (Albany NY) 2011; 3:584-96. [PMID: 21685510 PMCID: PMC3164367 DOI: 10.18632/aging.100336] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Genome stability of human embryonic stem cells (hESC) is an important issue because even minor genetic alterations can negatively impact cell functionality and safety. The incorrect repair of DNA double-stranded breaks (DSBs) is the ultimate cause of the formation of chromosomal aberrations. Using G2 radiosensitivity assay, we analyzed chromosomal aberrations in pluripotent stem cells and somatic cells. The chromatid exchange aberration rates in hESCs increased manifold 2 hours after irradiation as compared with their differentiated derivatives, but the frequency of radiation-induced chromatid breaks was similar. The rate of radiation-induced chromatid exchanges in hESCs and differentiated cells exhibited a quadratic dose response, revealing two-hit mechanism of exchange formation suggesting that a non-homologous end joining (NHEJ) repair may contribute to their formation. Inhibition of DNA-PK, a key NHEJ component, by NU7026 resulted in a significant decrease in radiation-induced chromatid exchanges in hESCs but not in somatic cells. In contrast, NU7026 treatment increased the frequency of radiation-induced breaks to a similar extent in pluripotent and somatic cells. Thus, DNA-PK dependent NHEJ efficiently participates in the elimination of radiation-induced chromatid breaks during the late G2 in both cell types and DNA-PK activity leads to a high level of misrejoining specifically in pluripotent cells.
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