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Kaur H, Salles DC, Murali S, Hicks JL, Nguyen M, Pritchard CC, De Marzo AM, Lanchbury JS, Trock BJ, Isaacs WB, Timms KM, Antonarakis ES, Lotan TL. Genomic and Clinicopathologic Characterization of ATM-deficient Prostate Cancer. Clin Cancer Res 2020; 26:4869-4881. [PMID: 32694154 PMCID: PMC7501149 DOI: 10.1158/1078-0432.ccr-20-0764] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/28/2020] [Accepted: 07/15/2020] [Indexed: 01/06/2023]
Abstract
PURPOSE The ATM (ataxia telangiectasia mutated) gene is mutated in a subset of prostate cancers, and ATM mutation may confer specific therapeutic vulnerabilities, although ATM-deficient prostate cancers have not been well-characterized. EXPERIMENTAL DESIGN We genetically validated a clinical grade IHC assay to detect ATM protein loss and examined the frequency of ATM loss among tumors with pathogenic germline ATM mutations and genetically unselected primary prostate carcinomas using tissue microarrays (TMAs). Immunostaining results were correlated with targeted somatic genomic sequencing and clinical outcomes. RESULTS ATM protein loss was found in 13% (7/52) of primary Gleason pattern 5 cancers with available sequencing data and was 100% sensitive for biallelic ATM inactivation. In a separate cohort with pathogenic germline ATM mutations, 74% (14/19) had ATM protein loss of which 70% (7/10) of evaluable cases had genomic evidence of biallelic inactivation, compared with zero of four of cases with intact ATM expression. By TMA screening, ATM loss was identified in 3% (25/831) of evaluable primary tumors, more commonly in grade group 5 (17/181; 9%) compared with all other grades (8/650; 1%; P < 0.0001). Of those with available sequencing, 80% (4/5) with homogeneous ATM protein loss and 50% (6/12) with heterogeneous ATM protein loss had detectable pathogenic ATM alterations. In surgically treated patients, ATM loss was not significantly associated with clinical outcomes in random-effects Cox models after adjusting for clinicopathologic variables. CONCLUSIONS ATM loss is enriched among high-grade prostate cancers. Optimal evaluation of ATM status requires both genomic and IHC studies and will guide development of molecularly targeted therapies.
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Affiliation(s)
- Harsimar Kaur
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Daniela C Salles
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Sanjana Murali
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Jessica L Hicks
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | | | - Colin C Pritchard
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Angelo M De Marzo
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | | | - Bruce J Trock
- Department of Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - William B Isaacs
- Department of Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Emmanuel S Antonarakis
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Tamara L Lotan
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland.
- Department of Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Zaki-Dizaji M, Akrami SM, Azizi G, Abolhassani H, Aghamohammadi A. Inflammation, a significant player of Ataxia-Telangiectasia pathogenesis? Inflamm Res 2018; 67:559-570. [PMID: 29582093 DOI: 10.1007/s00011-018-1142-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 02/03/2018] [Accepted: 03/21/2018] [Indexed: 12/21/2022] Open
Abstract
INTRODUCTION Ataxia-Telangiectasia (A-T) syndrome is an autosomal recessive neurodegenerative disorder characterized by cerebellar ataxia, oculocutaneous telangiectasia, immunodeficiency, chromosome instability, radiosensitivity, and predisposition to malignancy. There is growing evidence that A-T patients suffer from pathologic inflammation that is responsible for many symptoms of this syndrome, including neurodegeneration, autoimmunity, cardiovascular disease, accelerated aging, and insulin resistance. In addition, epidemiological studies have shown A-T heterozygotes, somewhat like deficient patients, are susceptible to ionizing irradiation and have a higher risk of cancers and metabolic disorders. AREA COVERED This review summarizes clinical and molecular findings of inflammation in A-T syndrome. CONCLUSION Ataxia-Telangiectasia Mutated (ATM), a master regulator of the DNA damage response is the protein known to be associated with A-T and has a complex nuclear and cytoplasmic role. Loss of ATM function may induce immune deregulation and systemic inflammation.
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Affiliation(s)
- Majid Zaki-Dizaji
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Immunodeficiencies, Children's Medical Center Hospital, Tehran University of Medical Science, 62 Qarib St., Keshavarz Blvd., Tehran, 14194, Iran
| | - Seyed Mohammad Akrami
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Gholamreza Azizi
- Non-Communicable Diseases Research Center, Alborz University of Medical Sciences, Karaj, Iran.,Department of Laboratory Medicine, Imam Hassan Mojtaba Hospital, Alborz University of Medical Sciences, Karaj, Iran
| | - Hassan Abolhassani
- Research Center for Immunodeficiencies, Children's Medical Center Hospital, Tehran University of Medical Science, 62 Qarib St., Keshavarz Blvd., Tehran, 14194, Iran.,Division of Clinical Immunology, Department of Laboratory Medicine, Karolinska Institute at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Asghar Aghamohammadi
- Research Center for Immunodeficiencies, Children's Medical Center Hospital, Tehran University of Medical Science, 62 Qarib St., Keshavarz Blvd., Tehran, 14194, Iran.
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Baek SJ, Chang JW, Park KH, Yang GY, Hwang HS, Koh YW, Jung YS, Kim CH. A novel synthetic compound 3-amino-3-(4-fluoro-phenyl)-1H-quinoline-2,4-dione (KR22332) exerts a radioprotective effect via the inhibition of mitochondrial dysfunction and generation of reactive oxygen species. Yonsei Med J 2014; 55:886-94. [PMID: 24954315 PMCID: PMC4075391 DOI: 10.3349/ymj.2014.55.4.886] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
PURPOSE Acute side effects of radiation such as oral mucositis are observed in most patients. Although several potential radioprotective agents have been proposed, no effective agent has yet been identified. In this study, we investigated the effectiveness of synthetic compound 3-amino-3-(4-fluoro-phenyl)-1H-quinoline-2,4-dione (KR22332) as a radioprotective agent. MATERIALS AND METHODS Cell viability, apoptosis, the generation of reactive oxygen species (ROS), mitochondrial membrane potential changes, and changes in apoptosis-related signaling were examined in human keratinocyte (HaCaT). RESULTS KR22332 inhibited irradiation-induced apoptosis and intracellular ROS generation, and it markedly attenuated the changes in mitochondrial membrane potential in primary human keratinocytes. Moreover, KR22332 significantly reduced the protein expression levels of ataxia telangiectasia mutated protein, p53, and tumor necrosis factor (TNF)-α compared to significant increases observed after radiation treatment. CONCLUSION KR22332 significantly inhibited radiation-induced apoptosis in human keratinocytes in vitro, indicating that it might be a safe and effective treatment for the prevention of radiation-induced mucositis.
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Affiliation(s)
- Seung Jae Baek
- Department of Otolaryngology-Head and Neck Surgery, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - Jae Won Chang
- Department of Otolaryngology, School of Medicine, Ajou University, Suwon, Korea. ; Center for Cell Death Regulating Biodrug, School of Medicine, Ajou University, Suwon, Korea
| | - Keun Hyung Park
- Department of Otolaryngology, School of Medicine, Ajou University, Suwon, Korea. ; Center for Cell Death Regulating Biodrug, School of Medicine, Ajou University, Suwon, Korea
| | - Garp Yeol Yang
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology, Daejeon, Korea
| | - Hye Sook Hwang
- Department of Otolaryngology, School of Medicine, Ajou University, Suwon, Korea. ; Center for Cell Death Regulating Biodrug, School of Medicine, Ajou University, Suwon, Korea
| | - Yoon Woo Koh
- Department of Otorhinolaryngology, Yonsei Head and Neck Cancer Clinic, Yonsei University College of Medicine, Seoul, Korea
| | - Young-Sik Jung
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology, Daejeon, Korea
| | - Chul-Ho Kim
- Department of Otolaryngology, School of Medicine, Ajou University, Suwon, Korea. ; Center for Cell Death Regulating Biodrug, School of Medicine, Ajou University, Suwon, Korea
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Chang JW, Park KH, HWANG HS, Shin YS, Oh YT, Kim CH. Protective effects of Korean red ginseng against radiation-induced apoptosis in human HaCaT keratinocytes. JOURNAL OF RADIATION RESEARCH 2014; 55:245-256. [PMID: 24078877 PMCID: PMC3951072 DOI: 10.1093/jrr/rrt109] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 07/28/2013] [Accepted: 08/15/2013] [Indexed: 06/02/2023]
Abstract
Radiation-induced oral mucositis is a dose-limiting toxic side effect for patients with head and neck cancer. Numerous attempts at improving radiation-induced oral mucositis have not produced a qualified treatment. Ginseng polysaccharide has multiple immunoprotective effects. Our aim was to investigate the effectiveness of Korean red ginseng (KRG) on radiation-induced damage in the human keratinocyte cell line HaCaT and in an in vivo zebrafish model. Radiation inhibited HaCaT cell proliferation and migration in a cell viability assay and wound healing assay, respectively. KRG protected against these effects. KRG attenuated the radiation-induced embryotoxicity in the zebrafish model. Irradiation of HaCaT cells caused apoptosis and changes in mitochondrial membrane potential (MMP). KRG inhibited the radiation-induced apoptosis and intracellular generation of reactive oxygen species (ROS), and stabilized the radiation-induced loss of MMP. Western blots revealed KRG-mediated reduced expression of ataxia telangiectasia mutated protein (ATM), p53, c-Jun N-terminal kinase (JNK), p38 and cleaved caspase-3, compared with their significant increase after radiation treatment. The collective results suggest that KRG protects HaCaT cells by blocking ROS generation, inhibiting changes in MMP, and inhibiting the caspase, ATM, p38 and JNK pathways.
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Affiliation(s)
- Jae Won Chang
- Department of Otolaryngology, School of Medicine, Ajou University, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, 442-749, Korea
- Center for Cell Death Regulating Biodrugs, School of Medicine, Ajou University, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, 442-749, Korea
| | - Keun Hyung Park
- Department of Otolaryngology, School of Medicine, Ajou University, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, 442-749, Korea
- Center for Cell Death Regulating Biodrugs, School of Medicine, Ajou University, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, 442-749, Korea
| | - Hye Sook HWANG
- Department of Otolaryngology, School of Medicine, Ajou University, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, 442-749, Korea
- Center for Cell Death Regulating Biodrugs, School of Medicine, Ajou University, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, 442-749, Korea
| | - Yoo Seob Shin
- Department of Otolaryngology, School of Medicine, Ajou University, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, 442-749, Korea
- Center for Cell Death Regulating Biodrugs, School of Medicine, Ajou University, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, 442-749, Korea
| | - Young-Taek Oh
- Department of Radiation Oncology, School of Medicine, Ajou University, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, 442-749, Korea
| | - Chul-Ho Kim
- Department of Otolaryngology, School of Medicine, Ajou University, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, 442-749, Korea
- Center for Cell Death Regulating Biodrugs, School of Medicine, Ajou University, 5 Wonchon-Dong, Yeongtong-Gu, Suwon, 442-749, Korea
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Yamamoto ML, Hafer K, Reliene R, Fleming S, Kelly O, Hacke K, Schiestl RH. Effects of 1 GeV/nucleon56Fe Particles on Longevity, Carcinogenesis and Neuromotor Ability inAtm-Deficient Mice. Radiat Res 2011; 175:231-9. [DOI: 10.1667/rr2312.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Turker MS, Connolly L, Dan C, Lasarev M, Gauny S, Kwoh E, Kronenberg A. Comparison of Autosomal Mutations in Mouse Kidney Epithelial Cells Exposed to Iron IonsIn Situor in Culture. Radiat Res 2009; 172:558-66. [DOI: 10.1667/rr1805.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Atm heterozygosity does not increase tumor susceptibility to ionizing radiation alone or in a p53 heterozygous background. Oncogene 2008; 27:6596-600. [PMID: 18679420 DOI: 10.1038/onc.2008.280] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ataxia-Telangiectasia (A-T) is an autosomal recessive human disease characterized by genetic instability, radiosensitivity, immunodeficiency and cancer predisposition, because of mutation in both alleles of the ATM (ataxia-telangiectasia mutated) gene. The role of Atm heterozygosity in cancer susceptibility is controversial, in both human and mouse. Earlier studies identified deletions near the Atm gene on mouse chromosome 9 in radiation-induced lymphomas from p53 heterozygous mice. To determine whether Atm was the target of these deletions, Atm heterozygous as well as Atm/P53 double heterozygous mice were treated with ionizing radiation. There were no significant differences in tumor latency, progression and lifespan after gamma-radiation in Atm heterozygous mice compared with their wild-type control counterparts. Deletions were found on chromosome 9 near the Atm locus in radiation-induced tumors, but in 50% of the cases the deletion included the knockout allele, and the expression of Atm was maintained in the tumors indicating that loss of heterozygosity on chromosome 9 is not driven by Atm, but by an alternative tumor suppressor gene located near Atm on this chromosome. We conclude that Atm heterozygosity does not confer an increase in tumor susceptibility in this context.
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Ahuja AK, Barber RC, Hardwick RJ, Weil MM, Genik PC, Brenner DJ, Dubrova YE. The effects of Atm haploinsufficiency on mutation rate in the mouse germ line and somatic tissue. Mutagenesis 2008; 23:367-70. [PMID: 18499649 DOI: 10.1093/mutage/gen028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Using single-molecule polymerase chain reaction, the frequency of spontaneous and radiation-induced mutation at an expanded simple tandem repeat (ESTR) locus was studied in DNA samples extracted from sperm and bone marrow of Atm knockout (Atm(+/-)) heterozygous male mice. The frequency of spontaneous mutation in sperm and bone marrow in Atm(+/-) males did not significantly differ from that in wild-type BALB/c mice. Acute exposure to 1 Gy of gamma-rays did not affect ESTR mutation frequency in bone marrow and resulted in similar increases in sperm samples taken from Atm(+/-) and BALB/c males. Taken together, these results suggest that the Atm haploinsufficiency analysed in our study does not affect spontaneous and radiation-induced ESTR mutation frequency in mice.
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Affiliation(s)
- Akshay K Ahuja
- Department of Genetics, University of Leicester, Leicester LE1 7RH, UK
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Day TK, Hooker AM, Zeng G, Sykes PJ. Low dose X-radiation adaptive response in spleen and prostate of Atm knockout heterozygous mice. Int J Radiat Biol 2007; 83:523-34. [PMID: 17613125 DOI: 10.1080/09553000701420582] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE To investigate the effect of being heterozygous for a knockout mutation in the ataxia telangiectasia (Atm) gene on radiation adaptive response. MATERIALS AND METHODS DNA recombination, as measured by pKZ1 inversion frequency, was quantified by histochemistry in Atm knockout heterozygous prostate and spleen 3 days after treatment with a priming dose of 0.01 or 10 mGy X-radiation 4 h prior to a challenge dose of 1,000 mGy. RESULTS In spleen and prostate, a single dose of 0.01 mGy caused an induction in inversion frequency but a dose of 10 mGy prevented the induction of a proportion of endogenous inversions. Both doses induced an adaptive response, of similar magnitude, to a subsequent high challenge dose for chromosomal inversions in both spleen and prostate. The adaptive response completely prevented the induction of inversions from a 1,000 mGy challenge dose and also a proportion of endogenous inversions. The adaptive responses and distribution of inversions across gland cross-sections observed here in Atm knockout heterozygote prostate were similar to those induced in Atm wild-type prostate in a previous study. CONCLUSIONS Being heterozygous for a knockout mutation in the Atm gene does not affect the endogenous pKZ1 inversion frequency, the inversion response to single low radiation doses used here, or the induction of a radiation adaptive response for inversions in pKZ1 mouse spleen or prostate.
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Affiliation(s)
- Tanya K Day
- Department of Haematology and Genetic Pathology, Flinders University and Medical Centre, Bedford Park, South Australia, Australia
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Edvardsen H, Tefre T, Jansen L, Vu P, Haffty BG, Fosså SD, Kristensen VN, Børresen-Dale AL. Linkage disequilibrium pattern of the ATM gene in breast cancer patients and controls; association of SNPs and haplotypes to radio-sensitivity and post-lumpectomy local recurrence. Radiat Oncol 2007; 2:25. [PMID: 17623063 PMCID: PMC1971057 DOI: 10.1186/1748-717x-2-25] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Accepted: 07/10/2007] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The ATM protein is activated as a result of ionizing radiation, and genetic variants of the ATM gene may therefore affect the level of radiation-induced damage. Individuals heterozygous for ATM mutations have been reported to have an increased risk of malignancy, especially breast cancer. MATERIALS AND METHODS Norwegian breast cancer patients (272) treated with radiation (252 of which were evaluated for radiation-induced adverse side effects), 95 Norwegian women with no known history of cancer and 95 American breast cancer patients treated with radiation (44 of which developed ipsilateral breast tumour recurrence, IBTR) were screened for sequence variations in all exons of the ATM gene as well as known intronic variants by denaturating high performance liquid chromatography (dHPLC) followed by sequencing to determine the nature of the variant. RESULTS AND CONCLUSION A total of 56 variants were identified in the three materials combined. A borderline significant association with breast cancer risk was found for the 1229 T>C (Val>Ala) substitution in exon 11 (P-value 0.055) between the Norwegian controls and breast cancer patients as well as a borderline significant difference in haplotype distribution (P-value 0.06). Adverse side effects, such as: development of costal fractures and telangiectasias, subcutaneous and lung fibrosis, pleural thickening and atrophy were evaluated in the Norwegian patients. Significant associations were found for several of the identified variants such as rs1800058 (Leu > Phe) where a decrease in minor allele frequency was found with increasing level of adverse side effects for the clinical end-points pleural thickening and lung fibrosis, thus giving a protective effect. Overall our results indicate a role for variation in the ATM gene both for risk of developing breast cancer, and in radiation induced adverse side effects. No association could be found between risk of developing ipsilateral breast tumour recurrence and any of the sequence variants found in the American patient material.
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Affiliation(s)
- Hege Edvardsen
- Department of Genetics, Institute for Cancer Research, Rikshospitalet-Radiumhospitalet Medical Centre, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Toril Tefre
- Biomedical Laboratory Sciences Program, Faculty of Health Science, Oslo University College, Oslo, Norway
| | - Laila Jansen
- Department of Genetics, Institute for Cancer Research, Rikshospitalet-Radiumhospitalet Medical Centre, Oslo, Norway
| | - Phuong Vu
- Department of Genetics, Institute for Cancer Research, Rikshospitalet-Radiumhospitalet Medical Centre, Oslo, Norway
| | - Bruce G Haffty
- Department of Radiation Oncology, Robert Wood Johnson Medical School Associate, Cancer Institute of New Jersey, New Jersey, USA
| | - Sophie D Fosså
- Department of Clinical Cancer Research, Rikshospitalet-Radiumhospitalet Medical Centre, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Vessela N Kristensen
- Department of Genetics, Institute for Cancer Research, Rikshospitalet-Radiumhospitalet Medical Centre, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Anne-Lise Børresen-Dale
- Department of Genetics, Institute for Cancer Research, Rikshospitalet-Radiumhospitalet Medical Centre, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
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Turker MS, Lasarev M, Connolly L, Kasameyer E, Roessler D. Age-related accumulation of autosomal mutations in solid tissues of the mouse is gender and cell type specific. Aging Cell 2007; 6:73-86. [PMID: 17266677 DOI: 10.1111/j.1474-9726.2006.00264.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Most cancers in solid tissues increase with age and invariably contain causal mutations eliminating expression of one or more autosomal tumor suppressor genes. However, very little is known about the effect of age on autosomal mutations, often large in size, in cells of solid tissues. In this study, the frequency and spectrum of autosomal mutations were examined as a function of age for kidney epithelial cells and ear mesenchymal cells in B6D2F1 mice heterozygous for the selectable Aprt locus. Aprt mutant frequencies were found to increase with age in the kidneys of both male and female mice, but at all ages the mutant frequencies were approximately twice as high in the females, which in this strain have shorter lifespans than the males. An age-related increase in Aprt mutant frequencies was also observed for ear cells from female mice, but no significant increases in mutant frequencies were observed for the ear cells of male mice. A molecular analysis showed that the kidney and ear mutational spectra were distinct and that the age-related increases in mutant frequencies did not involve significant shifts in the mutational spectra. In total, the results demonstrate both gender and cell-type-specific patterns of autosomal mutational accumulation as a function of age in two solid tissues of the mouse.
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Affiliation(s)
- Mitchell S Turker
- Center for Research on Occupational and Environmental Toxicology (CROET), Oregon Health and Science University, Portland, OR 97239, USA.
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