title: Pre-exposure to ionizing radiation stimulates DNA double strand break end resection, promoting the use of homologous recombination repair.
abstract: The choice of DNA double strand break (DSB) repair pathway is determined at the stage of DSB end resection. Resection was proposed to control the balance between the two major DSB repair pathways, homologous recombination (HR) and non-homologous end joining (NHEJ). Here, we examined the regulation of DSB repair pathway choice at two-ended DSBs following ionizing radiation (IR) in G2 phase of the cell cycle. We found that cells pre-exposed to low-dose IR preferred to undergo HR following challenge IR in G2, whereas NHEJ repair kinetics in G1 were not affected by pre-IR treatment. Consistent with the increase in HR usage, the challenge IR induced Replication protein A (RPA) foci formation and RPA phosphorylation, a marker of resection, were enhanced by pre-IR. However, neither major DNA damage signals nor the status of core NHEJ proteins, which influence the choice of repair pathway, was significantly altered in pre-IR treated cells. Moreover, the increase in usage of HR due to pre-IR exposure was prevented by treatment with ATM inhibitor during the incubation period between pre-IR and challenge IR. Taken together, the results of our study suggest that the ATM-dependent damage response after pre-IR changes the cellular environment, possibly by regulating gene expression or post-transcriptional modifications in a manner that promotes resection.
authors.affiliation: Research Center for Charged Particle Therapy and International Open Laboratory, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Nakako Izumi
authors.initials: NI
authors.lastname: Nakajima
authors.affiliation: Advanced Scientific Research Leaders Development Unit, Gunma University, Maebashi, Gunma, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Hagiwara
authors.affiliation: Department of Radiation Oncology, Gunma University, Maebashi, Gunma, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Oike
authors.affiliation: Research Center for Charged Particle Therapy and International Open Laboratory, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Okayasu
authors.affiliation: Research Center for Charged Particle Therapy and International Open Laboratory, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Murakami
authors.affiliation: Department of Radiation Oncology, Gunma University, Maebashi, Gunma, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakano
authors.affiliation: Advanced Scientific Research Leaders Development Unit, Gunma University, Maebashi, Gunma, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shibata
mesh_terms: D045744:Cell Line, Tumor; D004249:DNA Damage; D059765:Homologous Recombination; D006801:Humans; D010766:Phosphorylation; D011839:Radiation, Ionizing; D059767:Recombinational DNA Repair
references.citation: Mutat Res. 1996 Nov 4;358(2):231-5
references.pmid: 8946029
references.citation: Science. 2007 May 25;316(5828):1160-6
references.pmid: 17525332
references.citation: Cell Cycle. 2010 Feb 15;9(4):662-9
references.pmid: 20139725
references.citation: Nature. 2007 Nov 22;450(7169):509-14
references.pmid: 17965729
references.citation: Mol Cell. 2001 Feb;7(2):263-72
references.pmid: 11239455
references.citation: Nature. 2011 Oct 16;479(7372):241-4
references.pmid: 22002605
references.citation: Radiat Res. 2005 Oct;164(4 Pt 1):383-90
references.pmid: 16187740
references.citation: DNA Repair (Amst). 2007 Jun 1;6(6):712-22
references.pmid: 17241822
references.citation: Nature. 1995 Dec 21-28;378(6559):789-92
references.pmid: 8524414
references.citation: Genes Dev. 2001 Dec 15;15(24):3237-42
references.pmid: 11751629
references.citation: Crit Rev Biochem Mol Biol. 2011 Aug;46(4):271-83
references.pmid: 21524151
references.citation: Clin Oncol (R Coll Radiol). 2014 May;26(5):243-9
references.pmid: 24630811
references.citation: Mol Cell. 2014 Jan 9;53(1):7-18
references.pmid: 24316220
references.citation: Radiother Oncol. 2011 Oct;101(1):46-50
references.pmid: 21665305
references.citation: Mol Cell Biol. 2003 Aug;23(16):5706-15
references.pmid: 12897142
references.citation: Oncogene. 2011 May 5;30(18):2135-46
references.pmid: 21217779
references.citation: Mol Cancer Res. 2006 Mar;4(3):197-207
references.pmid: 16547157
references.citation: PLoS One. 2013 Aug 14;8(8):e70107
references.pmid: 23967070
references.citation: Nat Rev Mol Cell Biol. 2008 Aug;9(8):616-27
references.pmid: 18594563
references.citation: Annu Rev Genet. 2011;45:247-71
references.pmid: 21910633
references.citation: EMBO J. 2011 Mar 16;30(6):1079-92
references.pmid: 21317870
references.citation: J Cell Biol. 2007 Mar 12;176(6):749-55
references.pmid: 17353355
references.citation: Biochim Biophys Acta. 1998 Jul 23;1381(2):265-70
references.pmid: 9685674
references.citation: Mol Cell. 2012 Aug 24;47(4):497-510
references.pmid: 22920291
references.citation: Mol Cell Biol. 2010 Jul;30(13):3371-83
references.pmid: 20421415
references.citation: Radiat Environ Biophys. 2008 Nov;47(4):439-44
references.pmid: 18568359
references.citation: EMBO J. 2009 Nov 4;28(21):3413-27
references.pmid: 19779458
references.citation: Mol Cell Biol. 2011 Oct;31(19):4022-35
references.pmid: 21791604
references.citation: Nat Rev Mol Cell Biol. 2013 Apr;14(4):197-210
references.pmid: 23847781
references.citation: Nat Rev Clin Oncol. 2013 Jul;10(7):411-24
references.pmid: 23689752
references.citation: Radiat Res. 1996 Oct;146(4):369-73
references.pmid: 8927708
references.citation: Science. 1984 Feb 10;223(4636):594-7
references.pmid: 6695170
references.citation: Oncogene. 2004 Aug 23;23(38):6404-28
references.pmid: 15322514
references.citation: Radiat Res. 1966 Nov;29(3):450-74
references.pmid: 5924188
references.citation: Nucleic Acids Res. 2013 Nov;41(21):9719-31
references.pmid: 23969417
references.citation: Nat Rev Cancer. 2009 Aug;9(8):596-604
references.pmid: 19629073
references.citation: Mol Cell. 2012 Jul 27;47(2):320-9
references.pmid: 22841003
references.citation: Int J Radiat Biol Relat Stud Phys Chem Med. 1988 Jan;53(1):39-47
references.pmid: 3257477
references.citation: J Biol Chem. 2009 Apr 3;284(14):9558-65
references.pmid: 19202191
references.citation: Cancer Res. 2010 Oct 15;70(20):8045-54
references.pmid: 20924112
references.citation: Science. 1994 Oct 7;266(5182):66-71
references.pmid: 7545954
references.citation: Int J Radiat Oncol Biol Phys. 2009 Oct 1;75(2):489-96
references.pmid: 19735873
references.citation: Int J Radiat Biol. 2009 Dec;85(12):1061-81
references.pmid: 19995233
references.citation: Mol Cancer Ther. 2010 Jun;9(6):1775-87
references.pmid: 20530711
references.citation: Mutat Res. 1996 Nov 4;358(2):127-34
references.pmid: 8946017