scholarly journals Quantification of radiation-induced DNA double strand break repair foci to evaluate and predict biological responses to ionizing radiation

NAR Cancer ◽  
2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Sébastien Penninckx ◽  
Eloise Pariset ◽  
Egle Cekanaviciute ◽  
Sylvain V Costes
Keyword(s):  
Ionizing Radiation ◽  
Time Course ◽  
Dose Dependence ◽  
Strand Break ◽  
Double Strand Break ◽  
Confounding Factors ◽  
Dna Double Strand Break ◽  
Biological Interpretation ◽  
Radiation Induced

Abstract Radiation-induced foci (RIF) are nuclear puncta visualized by immunostaining of proteins that regulate DNA double-strand break (DSB) repair after exposure to ionizing radiation. RIF are a standard metric for measuring DSB formation and repair in clinical, environmental and space radiobiology. The time course and dose dependence of their formation has great potential to predict in vivo responses to ionizing radiation, predisposition to cancer and probability of adverse reactions to radiotherapy. However, increasing complexity of experimentally and therapeutically setups (charged particle, FLASH …) is associated with several confounding factors that must be taken into account when interpreting RIF values. In this review, we discuss the spatiotemporal characteristics of RIF development after irradiation, addressing the common confounding factors, including cell proliferation and foci merging. We also describe the relevant endpoints and mathematical models that enable accurate biological interpretation of RIF formation and resolution. Finally, we discuss the use of RIF as a biomarker for quantification and prediction of in vivo radiation responses, including important caveats relating to the choice of the biological endpoint and the detection method. This review intends to help scientific community design radiobiology experiments using RIF as a key metric and to provide suggestions for their biological interpretation.

A Review of Studies of Ionizing Radiation-Induced Double-Strand Break Clustering

2001 ◽  
Vol 156 (5) ◽  
pp. 572-576 ◽  
Author(s):  
K. M. Prise ◽  
M. Pinto ◽  
H. C. Newman ◽  
B. D. Michael
Keyword(s):  
Ionizing Radiation ◽  
Strand Break ◽  
Double Strand Break ◽  
Radiation Induced

The PARP inhibitor olaparib induces significant killing of ATM-deficient lymphoid tumor cells in vitro and in vivo

Blood ◽  
2010 ◽  
Vol 116 (22) ◽  
pp. 4578-4587 ◽  
Author(s):  
Victoria J. Weston ◽  
Ceri E. Oldreive ◽  
Anna Skowronska ◽  
David G. Oscier ◽  
Guy Pratt ◽  
...  
Keyword(s):  
Cell Line ◽  
Tumor Cells ◽  
Strand Break ◽  
Double Strand Break ◽  
Double Strand Break Repair ◽  
Prolymphocytic Leukemia ◽  
Dna Double Strand Break ◽  
Break Repair

Abstract The Ataxia Telangiectasia Mutated (ATM) gene is frequently inactivated in lymphoid malignancies such as chronic lymphocytic leukemia (CLL), T-prolymphocytic leukemia (T-PLL), and mantle cell lymphoma (MCL) and is associated with defective apoptosis in response to alkylating agents and purine analogues. ATM mutant cells exhibit impaired DNA double strand break repair. Poly (ADP-ribose) polymerase (PARP) inhibition that imposes the requirement for DNA double strand break repair should selectively sensitize ATM-deficient tumor cells to killing. We investigated in vitro sensitivity to the poly (ADP-ribose) polymerase inhibitor olaparib (AZD2281) of 5 ATM mutant lymphoblastoid cell lines (LCL), an ATM mutant MCL cell line, an ATM knockdown PGA CLL cell line, and 9 ATM-deficient primary CLLs induced to cycle and observed differential killing compared with ATM wildtype counterparts. Pharmacologic inhibition of ATM and ATM knockdown confirmed the effect was ATM-dependent and mediated through mitotic catastrophe independently of apoptosis. A nonobese diabetic/severe combined immunodeficient (NOD/SCID) murine xenograft model of an ATM mutant MCL cell line demonstrated significantly reduced tumor load and an increased survival of animals after olaparib treatment in vivo. Addition of olaparib sensitized ATM null tumor cells to DNA-damaging agents. We suggest that olaparib would be an appropriate agent for treating refractory ATM mutant lymphoid tumors.

scholarly journals RAD-51-Dependent and -Independent Roles of a Caenorhabditis elegans BRCA2-Related Protein during DNA Double-Strand Break Repair

2005 ◽  
Vol 25 (8) ◽  
pp. 3127-3139 ◽  
Author(s):  
Julie S. Martin ◽  
Nicole Winkelmann ◽  
Mark I. R. Petalcorin ◽  
Michael J. McIlwraith ◽  
Simon J. Boulton
Keyword(s):  
Caenorhabditis Elegans ◽  
Strand Break ◽  
Double Strand Break ◽  
Nonhomologous End Joining ◽  
Related Protein ◽  
End Joining ◽  
Dsb Repair ◽  
Phenotypic Differences ◽  
Dna Double Strand Break ◽  
Radiation Induced

ABSTRACT The BRCA2 tumor suppressor is implicated in DNA double-strand break (DSB) repair by homologous recombination (HR), where it regulates the RAD51 recombinase. We describe a BRCA2-related protein of Caenorhabditis elegans (CeBRC-2) that interacts directly with RAD-51 via a single BRC motif and that binds preferentially to single-stranded DNA through an oligonucleotide-oligosaccharide binding fold. Cebrc-2 mutants fail to repair meiotic or radiation-induced DSBs by HR due to inefficient RAD-51 nuclear localization and a failure to target RAD-51 to sites of DSBs. Genetic and cytological comparisons of Cebrc-2 and rad-51 mutants revealed fundamental phenotypic differences that suggest a role for Cebrc-2 in promoting the use of an alternative repair pathway in the absence of rad-51 and independent of nonhomologous end joining (NHEJ). Unlike rad-51 mutants, Cebrc-2 mutants also accumulate RPA-1 at DSBs, and abnormal chromosome aggregates that arise during the meiotic prophase can be rescued by blocking the NHEJ pathway. CeBRC-2 also forms foci in response to DNA damage and can do so independently of rad-51. Thus, CeBRC-2 not only regulates RAD-51 during HR but can also function independently of rad-51 in DSB repair processes.

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