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El Nachef L, Berthel E, Ferlazzo ML, Le Reun E, Al-Choboq J, Restier-Verlet J, Granzotto A, Sonzogni L, Bourguignon M, Foray N. Cancer and Radiosensitivity Syndromes: Is Impaired Nuclear ATM Kinase Activity the Primum Movens? Cancers (Basel) 2022; 14:cancers14246141. [PMID: 36551628 PMCID: PMC9776478 DOI: 10.3390/cancers14246141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/01/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022] Open
Abstract
There are a number of genetic syndromes associated with both high cancer risk and clinical radiosensitivity. However, the link between these two notions remains unknown. Particularly, some cancer syndromes are caused by mutations in genes involved in DNA damage signaling and repair. How are the DNA sequence errors propagated and amplified to cause cell transformation? Conversely, some cancer syndromes are caused by mutations in genes involved in cell cycle checkpoint control. How is misrepaired DNA damage produced? Lastly, certain genes, considered as tumor suppressors, are not involved in DNA damage signaling and repair or in cell cycle checkpoint control. The mechanistic model based on radiation-induced nucleoshuttling of the ATM kinase (RIANS), a major actor of the response to ionizing radiation, may help in providing a unified explanation of the link between cancer proneness and radiosensitivity. In the frame of this model, a given protein may ensure its own specific function but may also play additional biological role(s) as an ATM phosphorylation substrate in cytoplasm. It appears that the mutated proteins that cause the major cancer and radiosensitivity syndromes are all ATM phosphorylation substrates, and they generally localize in the cytoplasm when mutated. The relevance of the RIANS model is discussed by considering different categories of the cancer syndromes.
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Affiliation(s)
- Laura El Nachef
- Inserm, U1296 Unit, Radiation: Defense, Health and Environment, Centre Léon-Bérard, 69008 Lyon, France
| | - Elise Berthel
- Inserm, U1296 Unit, Radiation: Defense, Health and Environment, Centre Léon-Bérard, 69008 Lyon, France
| | - Mélanie L. Ferlazzo
- Inserm, U1296 Unit, Radiation: Defense, Health and Environment, Centre Léon-Bérard, 69008 Lyon, France
| | - Eymeric Le Reun
- Inserm, U1296 Unit, Radiation: Defense, Health and Environment, Centre Léon-Bérard, 69008 Lyon, France
| | - Joelle Al-Choboq
- Inserm, U1296 Unit, Radiation: Defense, Health and Environment, Centre Léon-Bérard, 69008 Lyon, France
| | - Juliette Restier-Verlet
- Inserm, U1296 Unit, Radiation: Defense, Health and Environment, Centre Léon-Bérard, 69008 Lyon, France
| | - Adeline Granzotto
- Inserm, U1296 Unit, Radiation: Defense, Health and Environment, Centre Léon-Bérard, 69008 Lyon, France
| | - Laurène Sonzogni
- Inserm, U1296 Unit, Radiation: Defense, Health and Environment, Centre Léon-Bérard, 69008 Lyon, France
| | - Michel Bourguignon
- Inserm, U1296 Unit, Radiation: Defense, Health and Environment, Centre Léon-Bérard, 69008 Lyon, France
- Department of Biophysics and Nuclear Medicine, Université Paris Saclay (UVSQ), 78035 Versailles, France
| | - Nicolas Foray
- Inserm, U1296 Unit, Radiation: Defense, Health and Environment, Centre Léon-Bérard, 69008 Lyon, France
- Correspondence: ; Tel.: +33-04-7878-2828
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Wang RH, Sengupta K, Li C, Kim HS, Cao L, Xiao C, Kim S, Xu X, Zheng Y, Chilton B, Jia R, Zheng ZM, Appella E, Wang XW, Ried T, Deng CX. Impaired DNA damage response, genome instability, and tumorigenesis in SIRT1 mutant mice. Cancer Cell 2008; 14:312-23. [PMID: 18835033 PMCID: PMC2643030 DOI: 10.1016/j.ccr.2008.09.001] [Citation(s) in RCA: 606] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Revised: 06/13/2008] [Accepted: 09/04/2008] [Indexed: 01/05/2023]
Abstract
In lower eukaryotes, Sir2 serves as a histone deacetylase and is implicated in chromatin silencing, longevity, and genome stability. Here we mutated the Sirt1 gene, a homolog of yeast Sir2, in mice to study its function. We show that a majority of SIRT1 null embryos die between E9.5 and E14.5, displaying altered histone modification, impaired DNA damage response, and reduced ability to repair DNA damage. We demonstrate that Sirt1(+/-);p53(+/-) mice develop tumors in multiple tissues, whereas activation of SIRT1 by resveratrol treatment reduces tumorigenesis. Finally, we show that many human cancers exhibit reduced levels of SIRT1 compared to normal controls. Thus, SIRT1 may act as a tumor suppressor through its role in DNA damage response and genome integrity.
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MESH Headings
- Animals
- Anticarcinogenic Agents/pharmacology
- Cell Cycle/genetics
- Cell Transformation, Neoplastic/drug effects
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/radiation effects
- Cells, Cultured
- Chromosomal Instability
- DNA Damage
- DNA Repair
- Down-Regulation
- Embryo, Mammalian/metabolism
- Embryo, Mammalian/pathology
- Female
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Neoplastic
- Genomic Instability
- Gestational Age
- Heterochromatin/metabolism
- Histones/metabolism
- Humans
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mitosis/genetics
- Mutation
- Neoplasms/enzymology
- Neoplasms/genetics
- Neoplasms/prevention & control
- Resveratrol
- Sirtuin 1
- Sirtuins/analysis
- Sirtuins/deficiency
- Sirtuins/genetics
- Sirtuins/metabolism
- Stilbenes/pharmacology
- Time Factors
- Tumor Suppressor Proteins/deficiency
- Tumor Suppressor Proteins/genetics
- Tumor Suppressor Proteins/metabolism
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Affiliation(s)
- Rui-Hong Wang
- Genetics of Development and Disease Branch, 10/9N105, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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Zheng YL, Loffredo CA, Alberg AJ, Yu Z, Jones RT, Perlmutter D, Enewold L, Krasna MJ, Yung R, Shields PG, Harris CC. Less efficient g2-m checkpoint is associated with an increased risk of lung cancer in African Americans. Cancer Res 2005; 65:9566-73. [PMID: 16230422 PMCID: PMC1403288 DOI: 10.1158/0008-5472.can-05-1003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cell cycle checkpoints play critical roles in the maintenance of genomic integrity. The inactivation of checkpoint genes by genetic and epigenetic mechanisms is frequent in all cancer types, as a less-efficient cell cycle control can lead to genetic instability and tumorigenesis. In an on-going case-control study consisting of 216 patients with non-small cell lung cancer, 226 population-based controls, and 114 hospital-based controls, we investigated the relationship of gamma-radiation-induced G2-M arrest and lung cancer risk. Peripheral blood lymphocytes were cultured for 90 hours, exposed to 1.0 Gy gamma-radiation, and harvested at 3 hours after gamma-radiation treatment. gamma-Radiation-induced G2-M arrest was measured as the percentage of mitotic cells in untreated cultures minus the percentage of mitotic cells in gamma-radiation-treated cultures from the same subject. The mean percentage of gamma-radiation-induced G2-M arrest was significantly lower in cases than in population controls (1.18 versus 1.44, P < 0.01) and hospital controls (1.18 versus 1.40, P = 0.01). When dichotomized at the 50th percentile value in combined controls (population and hospital controls), a lower level of gamma-radiation-induced G2-M arrest was associated with an increased risk of lung cancer among African Americans after adjusting for baseline mitotic index, age, gender, and pack-years of smoking [adjusted odd ratio (OR), 2.25; 95% confidence interval (95% CI), 0.97-5.20]. A significant trend of an increased risk of lung cancer with a decreased level of G2-M arrest was observed (P(trend) = 0.02) among African Americans, with a lowest-versus-highest quartile adjusted OR of 3.74 (95% CI, 0.98-14.3). This trend was most apparent among African American females (P(trend) < 0.01), with a lowest-versus-highest quartile adjusted OR of 11.75 (95% CI, 1.47-94.04). The results suggest that a less-efficient DNA damage-induced G2-M checkpoint is associated with an increased risk of lung cancer among African Americans. Interestingly, we observed a stronger association of DNA damage-induced G2-M arrest and lung cancer among African Americans when compared with Caucasians. If replicated, these results may provide clues to the exceedingly high lung cancer incidence experienced by African Americans.
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Affiliation(s)
- Yun-Ling Zheng
- Laboratory of Human Carcinogenesis, National Cancer Institute, Bethesda, Maryland
- Cancer Genetics and Epidemiology Program, Georgetown University, Washington, District of Columbia
| | - Christopher A. Loffredo
- Cancer Genetics and Epidemiology Program, Georgetown University, Washington, District of Columbia
| | | | - Zhipeng Yu
- Laboratory of Human Carcinogenesis, National Cancer Institute, Bethesda, Maryland
| | - Raymond T. Jones
- Department of Pathology and Surgery, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Donna Perlmutter
- Department of Pathology and Surgery, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Lindsey Enewold
- Cancer Genetics and Epidemiology Program, Georgetown University, Washington, District of Columbia
| | - Mark J. Krasna
- Department of Pathology and Surgery, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Rex Yung
- Pulmonary Medicine, Johns Hopkins Medical Institutions; and
| | - Peter G. Shields
- Cancer Genetics and Epidemiology Program, Georgetown University, Washington, District of Columbia
| | - Curtis C. Harris
- Laboratory of Human Carcinogenesis, National Cancer Institute, Bethesda, Maryland
- Requests for reprints: Curtis C. Harris, Laboratory of Human Carcinogenesis, Center For Cancer Research, National Cancer Institute, 37 Convent Drive, Building 37, Room 3068, Bethesda, MD 20892-4255. Phone: 301-496-2048; Fax: 301-496-0497; E-mail:
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Abstract
Iatrogenic malignancies represent a devastating and often fatal long-term effect of therapy administered for a prior condition, usually a primary cancer. Earlier diagnosis and the development of more effective cancer treatments over the last 30 years have considerably improved the long-term survival of patients. However, the burgeoning number of cancer survivors has led to a parallel increase in the number of cases of iatrogenic malignancy. Consequently, understanding host susceptibility factors, such that high-risk patients can be identified, has become a priority. However, this task is made difficult by the heterogeneity of iatrogenic malignancies. Nevertheless, the identification of polymorphic loci and pathways predicted to modify dose (e.g., glutathione S-transferases, nicotinamide adenine dinucleotide phosphate: quinone oxidoreductase, cytochrome P450, and thiopurine S-methyltransferase) or determine cellular outcome (e.g., nucleotide excision DNA repair, base excision DNA repair, DNA mismatch repair, and cell death signaling) after therapy has provided insight into how host genetics may impact on the risk of developing iatrogenic malignancy.
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Affiliation(s)
- James M Allan
- Department of Biology, Epidemiology and Genetics Unit, University of York, York, UK.
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Demuth I, Frappart PO, Hildebrand G, Melchers A, Lobitz S, Stöckl L, Varon R, Herceg Z, Sperling K, Wang ZQ, Digweed M. An inducible null mutant murine model of Nijmegen breakage syndrome proves the essential function of NBS1 in chromosomal stability and cell viability. Hum Mol Genet 2004; 13:2385-97. [PMID: 15333589 DOI: 10.1093/hmg/ddh278] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The human genetic disorder, Nijmegen breakage syndrome, is characterized by radiosensitivity, immunodeficiency, chromosomal instability and an increased risk for cancer of the lymphatic system. The NBS1 gene codes for a protein, nibrin, involved in the processing/repair of DNA double strand breaks and in cell cycle checkpoints. Most patients are homozygous for a founder mutation, a 5 bp deletion, which might not be a null mutation, as functionally relevant truncated nibrin proteins are observed, at least in vitro. In agreement with this hypothesis, null mutation of the homologous gene, Nbn, is lethal in mice. Here, we have used Cre recombinase/loxP technology to generate an inducible Nbn null mutation allowing the examination of DNA-repair and cell cycle-checkpoints in the complete absence of nibrin. Induction of Nbn null mutation leads to the loss of the G2/M checkpoint, increased chromosome damage, radiomimetic-sensitivity and cell death. In vivo, this particularly affects the lymphatic tissues, bone marrow, thymus and spleen, whereas liver, kidney and muscle are hardly affected. In vitro, null mutant murine fibroblasts can be rescued from cell death by transfer of human nibrin cDNA and, more significantly, by a cDNA carrying the 5 bp deletion. This demonstrates, for the first time, that the common human mutation is hypomorphic and that the expression of a truncated protein is sufficient to restore nibrin's vital cellular functions.
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Affiliation(s)
- Ilja Demuth
- Institut für Humangenetik, Charité Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin, Germany
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Digweed M, Sperling K. Nijmegen breakage syndrome: clinical manifestation of defective response to DNA double-strand breaks. DNA Repair (Amst) 2004; 3:1207-17. [PMID: 15279809 DOI: 10.1016/j.dnarep.2004.03.004] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Nijmegen breakage syndrome is a rare autosomal recessive genetic disease belonging to a group of disorders often called chromosome instability syndromes. In addition to a characteristic facial appearance and microcephaly, patients suffering from Nijmegen breakage syndrome have a range of symptoms including radiosensitivity, immunodeficiency, increased cancer risk and growth retardation. The underlying gene, NBS1, is located on human chromosome 8q21 and codes for a protein product termed nibrin, Nbs1 or p95. Over 90% of patients are homozygous for a founder mutation: a deletion of five base pairs which leads to a framehift and protein truncation. The protein nibrin/Nbs1 is suspected to be involved in the cellular response to DNA damage caused by ionising irradiation, thus accounting for the radiosensitivity of Nijmegen breakage syndrome. We review here some of the more recent findings on the NBS1 gene and discuss how they impinge on the clinical manifestation of the disease.
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Affiliation(s)
- Martin Digweed
- Institute of Human Genetics, Charité-University Medicine Berlin, Augustenburger platz 1, Berlin 13353, Germany.
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Barth E, Demori E, Pecile V, Zanazzo GA, Malorgio C, Tamaro P. Anthracyclines in Nijmegen breakage syndrome. MEDICAL AND PEDIATRIC ONCOLOGY 2003; 40:122-4. [PMID: 12461799 DOI: 10.1002/mpo.10079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Elsa Barth
- Department of Pediatric Onco-Haematology, Institute of Maternal and Child Health I.R.C.C.S., Burlo Garofolo--Trieste, Italy
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9
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Fernandez-Capetillo O, Chen HT, Celeste A, Ward I, Romanienko PJ, Morales JC, Naka K, Xia Z, Camerini-Otero RD, Motoyama N, Carpenter PB, Bonner WM, Chen J, Nussenzweig A. DNA damage-induced G2-M checkpoint activation by histone H2AX and 53BP1. Nat Cell Biol 2002; 4:993-7. [PMID: 12447390 DOI: 10.1038/ncb884] [Citation(s) in RCA: 521] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2002] [Revised: 10/30/2002] [Accepted: 10/31/2002] [Indexed: 11/09/2022]
Abstract
Activation of the ataxia telangiectasia mutated (ATM) kinase triggers diverse cellular responses to ionizing radiation (IR), including the initiation of cell cycle checkpoints. Histone H2AX, p53 binding-protein 1 (53BP1) and Chk2 are targets of ATM-mediated phosphorylation, but little is known about their roles in signalling the presence of DNA damage. Here, we show that mice lacking either H2AX or 53BP1, but not Chk2, manifest a G2-M checkpoint defect close to that observed in ATM(-/-) cells after exposure to low, but not high, doses of IR. Moreover, H2AX regulates the ability of 53BP1 to efficiently accumulate into IR-induced foci. We propose that at threshold levels of DNA damage, H2AX-mediated concentration of 53BP1 at double-strand breaks is essential for the amplification of signals that might otherwise be insufficient to prevent entry of damaged cells into mitosis.
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Affiliation(s)
- Oscar Fernandez-Capetillo
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Little JB, Nagasawa H, Dahlberg WK, Zdzienicka MZ, Burma S, Chen DJ. Differing responses of Nijmegen breakage syndrome and ataxia telangiectasia cells to ionizing radiation. Radiat Res 2002; 158:319-26. [PMID: 12175309 DOI: 10.1667/0033-7587(2002)158[0319:dronbs]2.0.co;2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Nijmegen breakage syndrome (NBS) is a rare autosomal recessive disorder. Originally thought to be a variant of ataxia telangiectasia (AT), the cellular phenotype of NBS has been described as almost indistinguishable from that of AT. Since the gene involved in NBS has been cloned and its functions studied, we sought to further characterize its cellular phenotype by examining the response of density-inhibited, confluent cultures of human diploid fibroblasts to irradiation in the G(0)/G(1) phase of the cell cycle. Both NBS and AT cells were markedly sensitive to the cytotoxic effects of radiation. NBS cells, however, were proficient in recovery from potentially lethal damage and exhibited a pronounced radiation-induced G(1)-phase arrest. Irradiated AT cells showed no potentially lethal damage and no G(1)-phase arrest. Both cell types were hypersensitive to the induction of chromosomal aberrations, whereas the distribution of aberrations in irradiated NBS cells was similar to that of normal controls, AT cells showed a high frequency of chromatid-type aberrations. TP53 and CDKN1A (also known as p21(Waf1)) expression was attenuated in irradiated NBS cells, but maximal induction occurred 2 h postirradiation, as was observed in normal controls. The similarities and differences in cellular phenotype between irradiated NBS and AT cells are discussed in terms of the functional properties of the signaling pathways downstream of AT involving the NBS1 and TP53 proteins.
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Affiliation(s)
- John B Little
- Harvard School of Public Health, 665 Huntington Avenue, Boston, Massachusetts 02115, USA.
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Girard PM, Riballo E, Begg AC, Waugh A, Jeggo PA. Nbs1 promotes ATM dependent phosphorylation events including those required for G1/S arrest. Oncogene 2002; 21:4191-9. [PMID: 12082606 DOI: 10.1038/sj.onc.1205596] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2002] [Revised: 04/03/2002] [Accepted: 04/17/2002] [Indexed: 11/09/2022]
Abstract
Cell lines from Nijmegen Breakage Syndrome (NBS) and ataxia telangiectasia (A-T) patients show defective S phase checkpoint arrest. In contrast, only A-T but not NBS cells are significantly defective in radiation-induced G1/S arrest. Phosphorylation of some ATM substrates has been shown to occur in NBS cells. It has, therefore, been concluded that Nbs1 checkpoint function is S phase specific. Here, we have compared NBS with A-T cell lines (AT-5762ins137) that express a low level of normal ATM protein to evaluate the impact of residual Nbs1 function in NBS cells. The radiation-induced cell cycle response of these NBS and 'leaky' A-T cells is almost identical; normal G2/M arrest after 2 Gy, intermediate G1/S arrest depending on the dose and an A-T-like S phase checkpoint defect. Thus, the checkpoint assays differ in their sensitivity to low ATM activity. Radiation-induced phosphorylation of the ATM-dependent substrates Chk2, RPAp34 and p53-Ser15 are similarly impaired in AT-5762ins137 and NBS cells in a dose dependent manner. In contrast, NBS cells show normal ability to activate ATM kinase following irradiation in vitro and in vivo. We propose that Nbs1 facilitates ATM-dependent phosphorylation of multiple downstream substrates, including those required for G1/S arrest.
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Affiliation(s)
- Pierre-Marie Girard
- MRC Cell Mutation Unit, University of Sussex, Brighton, East Sussex, BN1 9RR, UK
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Antoccia A, di Masi A, Maraschio P, Stumm M, Ricordy R, Tanzarella C. G2-phase radiation response in lymphoblastoid cell lines from Nijmegen breakage syndrome. Cell Prolif 2002; 35:93-104. [PMID: 11952644 PMCID: PMC6495264 DOI: 10.1046/j.1365-2184.2002.00234.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2001] [Accepted: 10/04/2001] [Indexed: 11/20/2022] Open
Abstract
The relationship between G2-phase checkpoint activation, cytoplasmic cyclin-B1 accumulation and nuclear phosphorylation of p34CDC2 was studied in Nijmegen breakage syndrome cells treated with DNA damaging agents. Experiments were performed on lymphoblastoid cell lines from four Nijmegen breakage syndrome patients with different mutations, as well as on cells from an ataxia telangiectasia patient. Lymphoblastoid cell lines were irradiated with 0.50-2 Gy X-rays and the percentage of G2-phase accumulated cells was evaluated by means of flow cytometry in samples that were harvested 24 h later. The G2-checkpoint activation was analysed by scoring the mitotic index at 2 and 4 h after treatment with 0.5 and 1 Gy X-rays and treatment with the DNA double-strand break inducer calicheamicin-gamma1. Cytoplasmic accumulation of cyclin-B1 was evaluated by means of fluorescence immunostaining or Western blotting, in cells harvested shortly after irradiation with 1 and 2 Gy. The extent of tyrosine 15-phosphorylated p34CDC2 was assessed in the nuclear fractions. Nijmegen breakage syndrome cells showed suboptimal G2-phase checkpoint activation respect to normal cells and were greatly different from ataxia telangiectasia cells. Increased cytoplasmic cyclin-B1 accumulation was detected by both immunofluorescence and immunoblot in normal as well as in Nijmegen breakage syndrome cells. Furthermore, nuclear p34CDC2. phosphorylation was detected at a higher level in Nijmegen breakage syndrome than in ataxia telangiectasia cells. In conclusion, our data do not suggest that failure to activate checkpoints plays a major role in the radiosensitivity of Nijmegen breakage syndrome cells.
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Affiliation(s)
- A Antoccia
- Università 'La Sapienza', Roma, Italy, Università degli Studi di Roma 'Roma Tre', Italy.
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Neubauer S, Arutyunyan R, Stumm M, Dörk T, Bendix R, Bremer M, Varon R, Sauer R, Gebhart E. Radiosensitivity of ataxia telangiectasia and Nijmegen breakage syndrome homozygotes and heterozygotes as determined by three-color FISH chromosome painting. Radiat Res 2002; 157:312-21. [PMID: 11839094 DOI: 10.1667/0033-7587(2002)157[0312:roatan]2.0.co;2] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A three-color chromosome painting technique was used to examine the spontaneous and radiation-induced chromosomal damage in peripheral lymphocytes and lymphoblastoid cells from 11 patients with ataxia telangiectasia (AT) and from 14 individuals heterozygous for an AT allele. In addition, cells from two homozygous and six obligate heterozygous carriers of mutations in the Nijmegen breakage syndrome gene (NBS) were investigated. The data were compared to those for chromosome damage in 10 unaffected control individuals and 48 cancer patients who had not yet received therapeutic treatment. Based on the well-documented radiation sensitivity of AT and NBS patients, it was of particular interest to determine whether the FISH painting technique used in these studies allowed the reliable detection of an increased sensitivity to in vitro irradiation of cells from heterozygous carriers. Peripheral blood lymphocytes and lymphoblastoid cells from both the homozygous AT and NBS patients showed the highest cytogenetic response, whereas the cells from control individuals had a low number of chromosomal aberrations. The response of cells from heterozygous carriers was intermediate and could be clearly differentiated from those of the other groups in double-coded studies. AT and NBS heterozygosity could be distinguished from other genotypes by the total number of breakpoints per cell and also by the number of the long-lived stable aberrations in both AT and NBS. Only AT heterozygosity could be distinguished by the fraction of unstable chromosome changes. The slightly but not significantly increased radiosensitivity that was found in cancer patients was apparently due to a higher trend toward rearrangements compared to the controls. Thus the three-color painting technique presented here proved to be well suited as a supplement to conventional cytogenetic techniques for the detection of heterozygous carriers of these diseases, and may be superior method.
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Affiliation(s)
- Susann Neubauer
- Clinic of Radiotherapy, University Erlangen-Nürnberg, Germany
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Grenon M, Gilbert C, Lowndes NF. Checkpoint activation in response to double-strand breaks requires the Mre11/Rad50/Xrs2 complex. Nat Cell Biol 2001; 3:844-7. [PMID: 11533665 DOI: 10.1038/ncb0901-844] [Citation(s) in RCA: 138] [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
Studies of human Nijmegen breakage syndrome (NBS) cells have led to the proposal that the Mre11/Rad50/ NBS1 complex, which is involved in the repair of DNA double-strand breaks (DSBs), might also function in activating the DNA damage checkpoint pathways after DSBs occur. We have studied the role of the homologous budding yeast complex, Mre11/Rad50/Xrs2, in checkpoint activation in response to DSB-inducing agents. Here we show that this complex is required for phosphorylation and activation of the Rad53 and Chk1 checkpoint kinases specifically in response to DSBs. Consistent with defective Rad53 activation, we observed defective cell-cycle delays after induction of DSBs in the absence of Mre11. Furthermore, after gamma-irradiation phosphorylation of Rad9, which is an early event in checkpoint activation, is also dependent on Mre11. All three components of the Mre11/Rad50/Xrs2 complex are required for activation of Rad53, however, the Ku80, Rad51 or Rad52 proteins, which are also involved in DSB repair, are not. Thus, the integrity of the Mre11/Rad50/Xrs2 complex is specifically required for checkpoint activation after the formation of DSBs.
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Affiliation(s)
- M Grenon
- ICRF Clare Hall Laboratories, CDC Laboratory, Blanche Lane, South Mimms, Potters Bar, Hertfordshire EN6 3LD, UK
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15
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Parshad R, Sanford KK. Radiation-induced chromatid breaks and deficient DNA repair in cancer predisposition. Crit Rev Oncol Hematol 2001; 37:87-96. [PMID: 11166582 DOI: 10.1016/s1040-8428(00)00111-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Deficient repair of DNA double-strand breaks, resulting in an abnormally high frequency of chromatid breaks after G(2) exposure of cells to radiation, appears to be associated with cancer predisposition. Unrepaired DNA strand breaks contribute to genomic instability. Unrepaired chromatid breaks representing DNA strand breaks can result in chromosome deletions, translocations and gene amplifications seen in human cancers. This cytogenetic response of cells to radiation may be useful as a marker of cancer susceptibility and in identifying individuals at risk of developing cancer in cancer families.
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Affiliation(s)
- R Parshad
- Department of Pathology, Howard University College of Medicine, 520 West Street, Washington, DC 20059, USA.
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van Duijn-Goedhart A, Zdzienicka MZ, Sankaranarayanan K, van Buul PP. Differential responses of Chinese hamster mutagen sensitive cell lines to low and high concentrations of calicheamicin and neocarzinostatin. Mutat Res 2000; 471:95-105. [PMID: 11080665 DOI: 10.1016/s1383-5718(00)00122-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To shed light on the mechanism underlying the cellular response to the radiomimetic agents calicheamicin Y(1)(1) (CAL) and neocarzinostatin (NCS), several hamster cell mutants defective in different DNA repair pathways were used. Two X-ray sensitive Chinese hamster V79 mutant cell lines, XR-V9B and V-E5 were studied for their response to the induction of cell killing, micronuclei, and G2-chromosomal aberrations relative to that of parental wild-type cells. In addition, effects of CAL and NCS on bleomycin sensitive BL-V40 cells and on UV sensitive V-H1 cells were analyzed. In general, the radiosensitive cell lines showed the highest sensitivities to CAL and NCS, but also the other mutants demonstrated differences in their responses compared to wild-type cells. With respect to cell killing, expressed as D(10)-value, enhanced sensitivities of mutants with factors up to 4.4 were recorded. For the induction of micronuclei (MN) and chromosomal aberrations (CA) all cell lines, including the parental cells, show a steep increase in the frequencies at the lowest tested doses and a leveling off at higher concentrations. Probably toxic effects at the higher exposure levels are responsible for these biphasic dose effect curves. Enhanced sensitivities of the various mutants were primarily observed at the higher exposure levels. With respect to the induction of MN increased sensitivities up to a factor of 18.1 were observed for the radiosensitive mutants, whereas for CA the mutant cell lines showed a variation from resistance (0.3) of VH-1 cells up to a 3.8-fold higher sensitivity to the radiomimetic agents. However, at the lowest tested concentrations for both MN and CA, the differences between the sensitive mutants and wild-type clearly diminished, suggesting the existence of residual and/or alternative DNA repair pathways in these mutants.
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Affiliation(s)
- A van Duijn-Goedhart
- MGC, LUMC--Department of Radiation Genetics and Chemical Mutagenesis, Sylvius Laboratory, Leiden University, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands
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Ito A, Tauchi H, Kobayashi J, Morishima K, Nakamura A, Hirokawa Y, Matsuura S, Ito K, Komatsu K. Expression of full-length NBS1 protein restores normal radiation responses in cells from Nijmegen breakage syndrome patients. Biochem Biophys Res Commun 1999; 265:716-21. [PMID: 10600486 DOI: 10.1006/bbrc.1999.1737] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cells from Nijmegen breakage syndrome (NBS) display multiple phenotypes, such as chromosomal instability, hypersensitivity to cell killing from ionizing radiation, and possibly abnormal cell cycle checkpoints. NBS1, a gene mutated in NBS patients, appears to encode a possible repair protein, which could form the foci of a sensor-like molecular complex capable of detecting DNA double strand breaks, however, it has no kinase domain for signaling DNA damage. Here, we report that the stable expression of NBS1 cDNA in NBS cells after transfection results in the complete restoration of foci formation in the nucleus, and in normal cell survival after irradiation. The prolonged G2 block observed after irradiation was also abolished by expression of NBS1, providing additional confirmation that the G2 checkpoint is abrogated in NBS cells. These results suggest that a defective NBS1 protein could be the sole cause of the NBS phenotype, and that NBS1 likely interacts with another protein(s) to produce the entire range of NBS phenotypic expression.
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Affiliation(s)
- A Ito
- Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
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18
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Abstract
The autosomal recessive genetic disorder, Nijmegen Breakage Syndrome, is characterised by an excessively high risk for the development of lymphatic tumours and an extreme sensitivity towards ionising radiation. The most likely explanation for these characteristics, a deficiency in the repair of DNA lesions, has been greatly substantiated by the recent cloning of the gene mutated in Nijmegen Breakage Syndrome patients and the analysis of its protein product, nibrin. The direct involvement of this protein in the processing of DNA double strand breaks caused by ionising radiation and those also necessary for normal DNA metabolism can be correlated with many of the cellular and clinical aspects of the disease, including the cancer predisposition of patients and their heterozygous relatives.
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Affiliation(s)
- M Digweed
- Institut für Humangenetik, Charité-Campus Virchow Klinikum, Humboldt Universität zu Berlin, Berlin, Germany.
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Kraakman-van der Zwet M, Overkamp WJ, Friedl AA, Klein B, Verhaegh GW, Jaspers NG, Midro AT, Eckardt-Schupp F, Lohman PH, Zdzienicka MZ. Immortalization and characterization of Nijmegen Breakage syndrome fibroblasts. Mutat Res 1999; 434:17-27. [PMID: 10377945 DOI: 10.1016/s0921-8777(99)00009-9] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Nijmegen Breakage Syndrome (NBS) is a very rare autosomal recessive chromosomal instability disorder characterized by microcephaly, growth retardation, immunodeficiency and a high incidence of malignancies. Cells from NBS patients are hypersensitive to ionizing radiation (IR) and display radioresistant DNA synthesis (RDS). NBS is caused by mutations in the NBS1 gene on chromosome 8q21 encoding a protein called nibrin. This protein is a component of the hMre11/hRad50 protein complex, suggesting a defect in DNA double-strand break (DSB) repair and/or cell cycle checkpoint function in NBS cells. We established SV40 transformed, immortal NBS fibroblasts, from primary cells derived from a Polish patient, carrying the common founder mutation 657del5. Immortalized NBS cells, like primary cells, are X-ray sensitive (2-fold) and display RDS following IR. They show an increased sensitivity to bleomycin (3.5-fold), etoposide (2.5-fold), camptothecin (3-fold) and mitomycin C (1.5-fold), but normal sensitivity towards UV-C. Despite the clear hypersensitivity towards DSB-inducing agents, the overall rates of DSB-rejoining in NBS cells as measured by pulsed field gel electrophoresis were found to be very similar to those of wild type cells. This indicates that the X-ray sensitivity of NBS cells is not directly caused by an overt defect in DSB repair.
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Affiliation(s)
- M Kraakman-van der Zwet
- MGC-Department of Radiation Genetics and Chemical Mutagenesis, Leiden University-LUMC, Netherlands
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Abstract
Gene mutations provide valuable clues to cellular metabolism. In humans such insights come mainly from genetic disorders. Ataxia-telangiectasia (A-T) and Nijmegen breakage syndrome (NBS) are two distinct but closely related, single gene disorders that highlight a complex junction of several signal transduction pathways. These pathways appear to control defense mechanisms against specific types of damage to cellular macromolecules, and probably regulate the processing of certain types of DNA damage or normal intermediates of DNA metabolism. A-T is characterized primarily by cerebellar degeneration, immunodeficiency, genome instability, clinical radiosensitivity, and cancer predisposition. NBS shares all these features except cerebellar deterioration. The cellular phenotypes of A-T and NBS are almost indistinguishable, however, and include chromosomal instability, radiosensitivity, and defects in cell cycle checkpoints normally induced by ionizing radiation. The recent identification of the gene responsible for A-T, ATM, has revealed its product to be a large, constitutively expressed phosphoprotein with a carboxy-terminal region similar to the catalytic domain of phosphatidylinositol 3-kinases (PI 3-kinases). ATM is a member of a family of proteins identified in various organisms, which share the PI 3-kinase domain and are involved in regulation of cell cycle progression and response to genotoxic agents. Some of these proteins, most notably the DNA-dependent protein kinase, have an associated protein kinase activity, and preliminary data indicate this activity in ATM as well. Mutations in A-T patients are null alleles that truncate or destabilize the ATM protein. Atm-deficient mice recapitulate the human phenotype with slower nervous-system degeneration. Two ATM interactors, c-Abl and p53, underscore its role in cellular responses to genotoxic stress. The complexity of ATM's structure and mode of action make it a paradigm of multifaceted signal transduction proteins involved in many physiological pathways via multiple protein-protein interactions. The as yet unknown NBS protein may be a component in an ATM-based complex, with a key role in sensing and processing specific DNA damage or intermediates and signaling their presence to the cell cycle machinery.
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Affiliation(s)
- Y Shiloh
- Department of Human Genetics, Sackler School of Medicine, Tel Aviv University, Israel.
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Matsuura K, Balmukhanov T, Tauchi H, Weemaes C, Smeets D, Chrzanowska K, Endou S, Matsuura S, Komatsu K. Radiation induction of p53 in cells from Nijmegen breakage syndrome is defective but not similar to ataxia-telangiectasia. Biochem Biophys Res Commun 1998; 242:602-7. [PMID: 9464263 DOI: 10.1006/bbrc.1997.7924] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
p53-mediated signal transduction after exposure to ionizing radiation was examined in cells from patients with Nijmegen breakage syndrome (NBS), an autosomal recessive disease characterized by microcephaly, immunodeficiency, predisposition to malignancy, and a high sensitivity to ionizing radiation. NBS cells accumulated p53 protein in a dose-dependent fashion, with a peak level 2 hrs after irradiation with 5 Gy. However, the maximal level of p53 protein in NBS cells was constantly lower than in normal cells. Moreover, this attenuation of p53 induction was confirmed by decreased levels of p21WAF1 protein, which is transcriptionally regulated by p53 protein. This defective induction of p53 protein in NBS is similar to that in ataxia-telangiectasia (AT), although the induced levels of p53 protein in NBS appeared to be the intermediate between normal cells and AT cells. This moderate p53 induction in NBS cells is consistent with the relatively mild radiation sensitivity and the abnormal cell cycle regulation post-irradiation, as present in NBS. Furthermore, all NBS cell lines used here exhibited time courses of p53 induction similar to normal cells, which is in contrast with p53 induction in AT cells, where the maximum induction shows a delay of approximately 2 hrs compared with normal cells. These evidences suggest a different function of each gene product in an upstream p53 response to radiation-induced DNA damage.
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Affiliation(s)
- K Matsuura
- Research Institute for Radiation Biology and Medicine, Hiroshima University, Japan
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