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Title: Deficiency in Homologous Recombination Renders Mammalian Cells More Sensitive to Proton Versus Photon Irradiation

Abstract

Purpose: To investigate the impact of the 2 major DNA repair machineries on cellular survival in response to irradiation with the 2 types of ionizing radiation. Methods and Materials: The DNA repair and cell survival endpoints in wild-type, homologous recombination (HR)-deficient, and nonhomologous end-joining-deficient cells were analyzed after irradiation with clinically relevant, low-linear energy transfer (LET) protons and 200-keV photons. Results: All cell lines were more sensitive to proton irradiation compared with photon irradiation, despite no differences in the induction of DNA breaks. Interestingly, HR-deficient cells and wild-type cells with small interfering RNA-down-regulated Rad51 were markedly hypersensitive to proton irradiation, resulting in an increased relative biological effectiveness in comparison with the relative biological effectiveness determined in wild-type cells. In contrast, lack of nonhomologous end-joining did not result in hypersensitivity toward proton irradiation. Repair kinetics of DNA damage in wild-type cells were equal after both types of irradiation, although proton irradiation resulted in more lethal chromosomal aberrations. Finally, repair kinetics in HR-deficient cells were significantly delayed after proton irradiation, with elevated amounts of residual γH2AX foci after irradiation. Conclusion: Our data indicate a differential quality of DNA damage by proton versus photon irradiation, with a specific requirement for homologous recombination formore » DNA repair and enhanced cell survival. This has potential relevance for clinical stratification of patients carrying mutations in the DNA damage response pathways.« less

Authors:
;  [1]; ; ;  [2];  [1];  [3];  [4];  [1]
  1. Laboratory for Molecular Radiobiology, University Hospital Zurich, Zurich (Switzerland)
  2. Center for Proton Therapy, Paul Scherrer Institute, Villigen (Switzerland)
  3. Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States)
  4. Institute of Molecular Cancer Research, University of Zurich, Zurich (Switzerland)
Publication Date:
OSTI Identifier:
22283329
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 88; Journal Issue: 1; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; CHROMOSOMAL ABERRATIONS; DNA DAMAGES; DNA REPAIR; IRRADIATION; KEV RANGE 100-1000; PROTON BEAMS; RADIOTHERAPY; RBE

Citation Formats

Grosse, Nicole, Fontana, Andrea O., Hug, Eugen B., Lomax, Antony, Coray, Adolf, Augsburger, Marc, Paganetti, Harald, Sartori, Alessandro A., and Pruschy, Martin, E-mail: martin.pruschy@usz.ch. Deficiency in Homologous Recombination Renders Mammalian Cells More Sensitive to Proton Versus Photon Irradiation. United States: N. p., 2014. Web. doi:10.1016/J.IJROBP.2013.09.041.
Grosse, Nicole, Fontana, Andrea O., Hug, Eugen B., Lomax, Antony, Coray, Adolf, Augsburger, Marc, Paganetti, Harald, Sartori, Alessandro A., & Pruschy, Martin, E-mail: martin.pruschy@usz.ch. Deficiency in Homologous Recombination Renders Mammalian Cells More Sensitive to Proton Versus Photon Irradiation. United States. doi:10.1016/J.IJROBP.2013.09.041.
Grosse, Nicole, Fontana, Andrea O., Hug, Eugen B., Lomax, Antony, Coray, Adolf, Augsburger, Marc, Paganetti, Harald, Sartori, Alessandro A., and Pruschy, Martin, E-mail: martin.pruschy@usz.ch. Wed . "Deficiency in Homologous Recombination Renders Mammalian Cells More Sensitive to Proton Versus Photon Irradiation". United States. doi:10.1016/J.IJROBP.2013.09.041.
@article{osti_22283329,
title = {Deficiency in Homologous Recombination Renders Mammalian Cells More Sensitive to Proton Versus Photon Irradiation},
author = {Grosse, Nicole and Fontana, Andrea O. and Hug, Eugen B. and Lomax, Antony and Coray, Adolf and Augsburger, Marc and Paganetti, Harald and Sartori, Alessandro A. and Pruschy, Martin, E-mail: martin.pruschy@usz.ch},
abstractNote = {Purpose: To investigate the impact of the 2 major DNA repair machineries on cellular survival in response to irradiation with the 2 types of ionizing radiation. Methods and Materials: The DNA repair and cell survival endpoints in wild-type, homologous recombination (HR)-deficient, and nonhomologous end-joining-deficient cells were analyzed after irradiation with clinically relevant, low-linear energy transfer (LET) protons and 200-keV photons. Results: All cell lines were more sensitive to proton irradiation compared with photon irradiation, despite no differences in the induction of DNA breaks. Interestingly, HR-deficient cells and wild-type cells with small interfering RNA-down-regulated Rad51 were markedly hypersensitive to proton irradiation, resulting in an increased relative biological effectiveness in comparison with the relative biological effectiveness determined in wild-type cells. In contrast, lack of nonhomologous end-joining did not result in hypersensitivity toward proton irradiation. Repair kinetics of DNA damage in wild-type cells were equal after both types of irradiation, although proton irradiation resulted in more lethal chromosomal aberrations. Finally, repair kinetics in HR-deficient cells were significantly delayed after proton irradiation, with elevated amounts of residual γH2AX foci after irradiation. Conclusion: Our data indicate a differential quality of DNA damage by proton versus photon irradiation, with a specific requirement for homologous recombination for DNA repair and enhanced cell survival. This has potential relevance for clinical stratification of patients carrying mutations in the DNA damage response pathways.},
doi = {10.1016/J.IJROBP.2013.09.041},
journal = {International Journal of Radiation Oncology, Biology and Physics},
number = 1,
volume = 88,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 2014},
month = {Wed Jan 01 00:00:00 EST 2014}
}
  • Purpose: To quantify and compare the effects of respiratory motion on paired passively scattered proton therapy (PSPT) and intensity modulated photon therapy (IMRT) plans; and to establish the relationship between the magnitude of tumor motion and the respiratory-induced dose difference for both modalities. Methods and Materials: In a randomized clinical trial comparing PSPT and IMRT, radiation therapy plans have been designed according to common planning protocols. Four-dimensional (4D) dose was computed for PSPT and IMRT plans for a patient cohort with respiratory motion ranging from 3 to 17 mm. Image registration and dose accumulation were performed using grayscale-based deformable imagemore » registration algorithms. The dose–volume histogram (DVH) differences (4D-3D [3D = 3-dimensional]) were compared for PSPT and IMRT. Changes in 4D-3D dose were correlated to the magnitude of tumor respiratory motion. Results: The average 4D-3D dose to 95% of the internal target volume was close to zero, with 19 of 20 patients within 1% of prescribed dose for both modalities. The mean 4D-3D between the 2 modalities was not statistically significant (P<.05) for all dose–volume histogram indices (mean ± SD) except the lung V5 (PSPT: +1.1% ± 0.9%; IMRT: +0.4% ± 1.2%) and maximum cord dose (PSPT: +1.5 ± 2.9 Gy; IMRT: 0.0 ± 0.2 Gy). Changes in 4D-3D dose were correlated to tumor motion for only 2 indices: dose to 95% planning target volume, and heterogeneity index. Conclusions: With our current margin formalisms, target coverage was maintained in the presence of respiratory motion up to 17 mm for both PSPT and IMRT. Only 2 of 11 4D-3D indices (lung V5 and spinal cord maximum) were statistically distinguishable between PSPT and IMRT, contrary to the notion that proton therapy will be more susceptible to respiratory motion. Because of the lack of strong correlations with 4D-3D dose differences in PSPT and IMRT, the extent of tumor motion was not an adequate predictor of potential dosimetric error caused by breathing motion.« less
  • Purpose: To provide the foundation for combining immunotherapy to induce tumor antigen–specific T cells with proton radiation therapy to exploit the activity of those T cells. Methods and Materials: Using cell lines of tumors frequently treated with proton radiation, such as prostate, breast, lung, and chordoma, we examined the effect of proton radiation on the viability and induction of immunogenic modulation in tumor cells by flow cytometric and immunofluorescent analysis of surface phenotype and the functional immune consequences. Results: These studies show for the first time that (1) proton and photon radiation induced comparable up-regulation of surface molecules involved in immune recognition (histocompatibilitymore » leukocyte antigen, intercellular adhesion molecule 1, and the tumor-associated antigens carcinoembryonic antigen and mucin 1); (2) proton radiation mediated calreticulin cell-surface expression, increasing sensitivity to cytotoxic T-lymphocyte killing of tumor cells; and (3) cancer stem cells, which are resistant to the direct cytolytic activity of proton radiation, nonetheless up-regulated calreticulin after radiation in a manner similar to non-cancer stem cells. Conclusions: These findings offer a rationale for the use of proton radiation in combination with immunotherapy, including for patients who have failed radiation therapy alone or have limited treatment options.« less
  • No abstract prepared.
  • Metabolites of two structurally related chemical carcinogens, benzo(a)pyrene and 1-nitropyrene, were compared for their ability to cause cytotoxicity and induce mutations in normally repairing or nucleotide excision repair-deficient diploid human fibroblasts; for their ability to induce mutations in a defined gene sequence, supF, when a plasmid containing adducts formed by these carcinogens replicates in human 293 cells; and for their ability to induce homologous recombination between duplicated genes in mouse L cells. Both of the metabolites tested form adducts of guanine. Results of the studies in diploid human cells indicated that when compared on the basis of equal numbers ofmore » DNA adducts, BPDE is more effective than 1-NOP in inducing mutations in DNA repair-proficient cells, but when compared in repair-deficient xeroderma pigmentosum human cells that do not remove such adducts from their DNA, the frequency of mutants induced per adduct is equal. These results suggest that during the time available for repair of potentially mutagenic lesions, repair-proficient human cells excise 1-NOP adducts more rapidly than they excise BPDE adducts. Molecular analysis of the specific kinds of mutations induced when a plasmid containing BPDE residues was allowed to replicate in human cells showed that BPDE induces mainly base substitution mutations, predominantly G:C to T:A transversions. Just as was the case for mutation induction in the genome of diploid human fibroblasts discussed above, the difference in mutagenicity per adduct may reflect a difference in excision repair rate by the human cell line 293. This question is under investigation. In addition, preliminary results of a study comparing 1-NOP with BPDE for ability to induce homologous recombination in mouse L cells indicate that BPDE is more effective than 1-NOP« less
  • The authors examined the fate of DNA microinjected into nuclei of cultured mammalian cells. The sequence composition and the physical form of the vector carrying the selectable gene affected the efficiency of DNA-mediated transformation. Introduction of sequences near the simian virus 40 origin of DNA replication or in the long terminal repeat of avian sarcoma provirus into a recombinant plasmid containing the herpes simplex virus thymidine kinase gene (pBR322/HSV-tk) enhanced the frequency of transformation of LMtk/sup -/ and RAT-2tk/sup -/ cells to the TK/sup +/ phenotype 20- to 40-fold. In cells receiving injections of only a few plasmid DNA molecules,more » the transformation frequency was 40-fold higher after injection of linear molecules than after injection of supercoiled molecules. By controlling the number of gene copies injected into a recipient cell, we could obtain transformants containing a single copy or as many as 50 to 100 copies of the selectable gene. By analyzing transformants obtained by coinjecting two vectors which were identical except that in one a portion of the vector was inverted, the authors were able to conclude that the head-to-tail concatemers were generated predominantly by homologous recombination. Surprisingly, these head-to-tail concatemers were found in transformants obtained by injecting either supercoiled or linear plasmid DNA.« less