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Analysis of chromosomal aberrations and γH2A.X foci to identify radiation-sensitive ataxia-telangiectasia patients.

Authors :
Bucher M
Endesfelder D
Roessler U
Borkhardt A
Dückers G
Kirlum HJ
Lankisch P
Oommen PT
Niehues T
Rübe CE
Baumgartner I
Bunk F
Moertl S
Hornhardt S
Gomolka M
Source :
Mutation research. Genetic toxicology and environmental mutagenesis [Mutat Res Genet Toxicol Environ Mutagen] 2021 Jan-Feb; Vol. 861-862, pp. 503301. Date of Electronic Publication: 2020 Dec 10.
Publication Year :
2021

Abstract

Ataxia-telangiectasia (AT) is a rare inherited recessive disorder which is caused by a mutated Ataxia-telangiectasia mutated (ATM) gene. Hallmarks include chromosomal instability, cancer predisposition and increased sensitivity to ionizing radiation. The ATM protein plays an important role in signaling of DNA double-strand breaks (DSB), thereby phosphorylating the histone H2A.X. Non-functional ATM protein leads to defects in DNA damage response, unresolved DSBs and genomic instability. The aim of this study was to evaluate chromosomal aberrations and γH2A.X foci as potential radiation sensitivity biomarkers in AT patients. For this purpose, lymphocytes of 8 AT patients and 10 healthy controls were irradiated and induced DNA damage and DNA repair capacity were detected by the accumulation of γH2A.X foci. The results were heterogeneous among AT patients. Evaluation revealed 2 AT patients with similar γH2A.X foci numbers as controls after 1 h while 3 patients showed a lower induction. In regard to DNA repair, 3 of 5 AT patients showed poor damage repair. Therefore, DNA damage induction and DNA repair as detected by H2A.X phosphorylation revealed individual differences, seems to depend on the underlying individual mutation and thus appears not well suited as a biomarker for radiation sensitivity. In addition, chromosomal aberrations were analyzed by mFISH. An increased frequency of spontaneous chromosomal breakage was characteristic for AT cells. After irradiation, significantly increased rates for non-exchange aberrations, translocations, complex aberrations and dicentric chromosomes were observed in AT patients compared to controls. The results of this study suggested, that complex aberrations and dicentric chromosomes might be a reliable biomarker for radiation sensitivity in AT patients, while non-exchange aberrations and translocations identified both, spontaneous and radiation-induced chromosomal instability.<br /> (Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.)

Details

Language :
English
ISSN :
1879-3592
Volume :
861-862
Database :
MEDLINE
Journal :
Mutation research. Genetic toxicology and environmental mutagenesis
Publication Type :
Academic Journal
Accession number :
33551102
Full Text :
https://doi.org/10.1016/j.mrgentox.2020.503301