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Warmenhoven JW, Henthorn NT, McNamara AL, Ingram SP, Merchant MJ, Kirkby KJ, Schuemann J, Paganetti H, Prise KM, McMahon SJ. Effects of Differing Underlying Assumptions in In Silico Models on Predictions of DNA Damage and Repair. Radiat Res 2023; 200:509-522. [PMID: 38014593 DOI: 10.1667/rade-21-00147.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/05/2023] [Indexed: 11/29/2023]
Abstract
The induction and repair of DNA double-strand breaks (DSBs) are critical factors in the treatment of cancer by radiotherapy. To investigate the relationship between incident radiation and cell death through DSB induction many in silico models have been developed. These models produce and use custom formats of data, specific to the investigative aims of the researchers, and often focus on particular pairings of damage and repair models. In this work we use a standard format for reporting DNA damage to evaluate combinations of different, independently developed, models. We demonstrate the capacity of such inter-comparison to determine the sensitivity of models to both known and implicit assumptions. Specifically, we report on the impact of differences in assumptions regarding patterns of DNA damage induction on predicted initial DSB yield, and the subsequent effects this has on derived DNA repair models. The observed differences highlight the importance of considering initial DNA damage on the scale of nanometres rather than micrometres. We show that the differences in DNA damage models result in subsequent repair models assuming significantly different rates of random DSB end diffusion to compensate. This in turn leads to disagreement on the mechanisms responsible for different biological endpoints, particularly when different damage and repair models are combined, demonstrating the importance of inter-model comparisons to explore underlying model assumptions.
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Affiliation(s)
- John W Warmenhoven
- Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom
- The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Nicholas T Henthorn
- Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom
- The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Aimee L McNamara
- Physics Division, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Massachusetts
| | - Samuel P Ingram
- Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, United Kingdom
| | - Michael J Merchant
- Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom
- The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Karen J Kirkby
- Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom
- The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Jan Schuemann
- Physics Division, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Massachusetts
| | - Harald Paganetti
- Physics Division, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Massachusetts
| | - Kevin M Prise
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, United Kingdom
| | - Stephen J McMahon
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, United Kingdom
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2
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Guerra Liberal FDC, Thompson SJ, Prise KM, McMahon SJ. High-LET radiation induces large amounts of rapidly-repaired sublethal damage. Sci Rep 2023; 13:11198. [PMID: 37433844 PMCID: PMC10336062 DOI: 10.1038/s41598-023-38295-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 07/06/2023] [Indexed: 07/13/2023] Open
Abstract
There is agreement that high-LET radiation has a high Relative Biological Effectiveness (RBE) when delivered as a single treatment, but how it interacts with radiations of different qualities, such as X-rays, is less clear. We sought to clarify these effects by quantifying and modelling responses to X-ray and alpha particle combinations. Cells were exposed to X-rays, alpha particles, or combinations, with different doses and temporal separations. DNA damage was assessed by 53BP1 immunofluorescence, and radiosensitivity assessed using the clonogenic assay. Mechanistic models were then applied to understand trends in repair and survival. 53BP1 foci yields were significantly reduced in alpha particle exposures compared to X-rays, but these foci were slow to repair. Although alpha particles alone showed no inter-track interactions, substantial interactions were seen between X-rays and alpha particles. Mechanistic modelling suggested that sublethal damage (SLD) repair was independent of radiation quality, but that alpha particles generated substantially more sublethal damage than a similar dose of X-rays, [Formula: see text]. This high RBE may lead to unexpected synergies for combinations of different radiation qualities which must be taken into account in treatment design, and the rapid repair of this damage may impact on mechanistic modelling of radiation responses to high LETs.
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Affiliation(s)
- Francisco D C Guerra Liberal
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK
| | - Shannon J Thompson
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK
| | - Kevin M Prise
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK
| | - Stephen J McMahon
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK.
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3
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Zagelbaum J, Gautier J. Double-strand break repair and mis-repair in 3D. DNA Repair (Amst) 2023; 121:103430. [PMID: 36436496 PMCID: PMC10799305 DOI: 10.1016/j.dnarep.2022.103430] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/13/2022] [Accepted: 11/15/2022] [Indexed: 11/18/2022]
Abstract
DNA double-strand breaks (DSBs) are lesions that arise frequently from exposure to damaging agents as well as from ongoing physiological DNA transactions. Mis-repair of DSBs leads to rearrangements and structural variations in chromosomes, including insertions, deletions, and translocations implicated in disease. The DNA damage response (DDR) limits pathologic mutations and large-scale chromosome rearrangements. DSB repair initiates in 2D at DNA lesions with the stepwise recruitment of repair proteins and local chromatin remodeling which facilitates break accessibility. More complex structures are then formed via protein assembly into nanodomains and via genome folding into chromatin loops. Subsequently, 3D reorganization of DSBs is guided by clustering forces which drive the assembly of repair domains harboring multiple lesions. These domains are further stabilized and insulated into condensates via liquid-liquid phase-separation. Here, we discuss the benefits and risks associated with this 3D reorganization of the broken genome.
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Affiliation(s)
- Jennifer Zagelbaum
- Institute for Cancer Genetics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Jean Gautier
- Institute for Cancer Genetics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Department of Genetics and Development, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
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Geometrical Properties of the Nucleus and Chromosome Intermingling Are Possible Major Parameters of Chromosome Aberration Formation. Int J Mol Sci 2022; 23:ijms23158638. [PMID: 35955776 PMCID: PMC9368922 DOI: 10.3390/ijms23158638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/28/2022] [Accepted: 07/30/2022] [Indexed: 12/10/2022] Open
Abstract
Ionizing radiation causes chromosome aberrations, which are possible biomarkers to assess space radiation cancer risks. Using the Monte Carlo codes Relativistic Ion Tracks (RITRACKS) and Radiation-Induced Tracks, Chromosome Aberrations, Repair and Damage (RITCARD), we investigated how geometrical properties of the cell nucleus, irradiated with ion beams of linear energy transfer (LET) ranging from 0.22 keV/μm to 195 keV/μm, influence the yield of simple and complex exchanges. We focused on the effect of (1) nuclear volume by considering spherical nuclei of varying radii; (2) nuclear shape by considering ellipsoidal nuclei of varying thicknesses; (3) beam orientation; and (4) chromosome intermingling by constraining or not constraining chromosomes in non-overlapping domains. In general, small nuclear volumes yield a higher number of complex exchanges, as compared to larger nuclear volumes, and a higher number of simple exchanges for LET < 40 keV/μm. Nuclear flattening reduces complex exchanges for high-LET beams when irradiated along the flattened axis. The beam orientation also affects yields for ellipsoidal nuclei. Reducing chromosome intermingling decreases both simple and complex exchanges. Our results suggest that the beam orientation, the geometry of the cell nucleus, and the organization of the chromosomes within are important parameters for the formation of aberrations that must be considered to model and translate in vitro results to in vivo risks.
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Ingram SP, Warmenhoven JW, Henthorn NT, Chadiwck AL, Santina EE, McMahon SJ, Schuemann J, Kirkby NF, Mackay RI, Kirkby KJ, Merchant MJ. A computational approach to quantifying miscounting of radiation-induced double-strand break immunofluorescent foci. Commun Biol 2022; 5:700. [PMID: 35835982 PMCID: PMC9283546 DOI: 10.1038/s42003-022-03585-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 06/14/2022] [Indexed: 11/09/2022] Open
Abstract
Immunofluorescent tagging of DNA double-strand break (DSB) markers, such as γ-H2AX and other DSB repair proteins, are powerful tools in understanding biological consequences following irradiation. However, whilst the technique is widespread, there are many uncertainties related to its ability to resolve and reliably deduce the number of foci when counting using microscopy. We present a new tool for simulating radiation-induced foci in order to evaluate microscope performance within in silico immunofluorescent images. Simulations of the DSB distributions were generated using Monte Carlo track-structure simulation. For each DSB distribution, a corresponding DNA repair process was modelled and the un-repaired DSBs were recorded at several time points. Corresponding microscopy images for both a DSB and (γ-H2AX) fluorescent marker were generated and compared for different microscopes, radiation types and doses. Statistically significant differences in miscounting were found across most of the tested scenarios. These inconsistencies were propagated through to repair kinetics where there was a perceived change between radiation-types. These changes did not reflect the underlying repair rate and were caused by inconsistencies in foci counting. We conclude that these underlying uncertainties must be considered when analysing images of DNA damage markers to ensure differences observed are real and are not caused by non-systematic miscounting. PyFoci is a tool that simulates distributions of fluorescently labeled DNA double-strand break marker protein foci and allows the estimation of miscounting under different radiation types, doses and microscopy settings.
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Affiliation(s)
- Samuel P Ingram
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK. .,Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Wilmslow Rd, Manchester, M20 4BX, UK.
| | - John-William Warmenhoven
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.,The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Wilmslow Rd, Manchester, M20 4BX, UK
| | - Nicholas T Henthorn
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.,The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Wilmslow Rd, Manchester, M20 4BX, UK
| | - Amy L Chadiwck
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.,The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Wilmslow Rd, Manchester, M20 4BX, UK
| | - Elham E Santina
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.,The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Wilmslow Rd, Manchester, M20 4BX, UK
| | - Stephen J McMahon
- Patrick G Johnston Centre for Cancer Research, Queens University Belfast, 97 Lisburn Rd, Belfast, BT9 7AE, UK
| | - Jan Schuemann
- Massachusetts General Hospital and Harvard Medical School, Department of Radiation Oncology, 30 Fruit Street, Boston, MA, 02114, USA
| | - Norman F Kirkby
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.,The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Wilmslow Rd, Manchester, M20 4BX, UK
| | - Ranald I Mackay
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.,Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Wilmslow Rd, Manchester, M20 4BX, UK
| | - Karen J Kirkby
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.,The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Wilmslow Rd, Manchester, M20 4BX, UK
| | - Michael J Merchant
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.,The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Wilmslow Rd, Manchester, M20 4BX, UK
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McMahon SJ, Prise KM. A Mechanistic DNA Repair and Survival Model (Medras): Applications to Intrinsic Radiosensitivity, Relative Biological Effectiveness and Dose-Rate. Front Oncol 2021; 11:689112. [PMID: 34268120 PMCID: PMC8276175 DOI: 10.3389/fonc.2021.689112] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/31/2021] [Indexed: 01/04/2023] Open
Abstract
Variations in the intrinsic radiosensitivity of different cells to ionizing radiation is now widely believed to be a significant driver in differences in response to radiotherapy. While the mechanisms of radiosensitivity have been extensively studied in the laboratory, there are a lack of models which integrate this knowledge into a predictive framework. This paper presents an overview of the Medras model, which has been developed to provide a mechanistic framework in which different radiation responses can be modelled and individual responses predicted. This model simulates the repair of radiation-induced DNA damage, incorporating the overall kinetics of repair and its fidelity, to predict a range of biological endpoints including residual DNA damage, mutation, chromosome aberration, and cell death. Validation of this model against a range of exposure types is presented, including considerations of varying radiation qualities and dose-rates. This approach has the potential to inform new tools to deliver mechanistic predictions of radiation sensitivity, and support future developments in treatment personalization.
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Affiliation(s)
- Stephen Joseph McMahon
- Patrick G Johnston Centre for Cancer Research, Queen’s University Belfast, Belfast, United Kingdom
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Qi Y, Warmenhoven JW, Henthorn NT, Ingram SP, Xu XG, Kirkby KJ, Merchant MJ. Mechanistic Modelling of Slow and Fast NHEJ DNA Repair Pathways Following Radiation for G0/G1 Normal Tissue Cells. Cancers (Basel) 2021; 13:2202. [PMID: 34063683 PMCID: PMC8124137 DOI: 10.3390/cancers13092202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/23/2021] [Accepted: 04/29/2021] [Indexed: 01/12/2023] Open
Abstract
Mechanistic in silico models can provide insight into biological mechanisms and highlight uncertainties for experimental investigation. Radiation-induced double-strand breaks (DSBs) are known to be toxic lesions if not repaired correctly. Non-homologous end joining (NHEJ) is the major DSB-repair pathway available throughout the cell cycle and, recently, has been hypothesised to consist of a fast and slow component in G0/G1. The slow component has been shown to be resection-dependent, requiring the nuclease Artemis to function. However, the pathway is not yet fully understood. This study compares two hypothesised models, simulating the action of individual repair proteins on DSB ends in a step-by-step manner, enabling the modelling of both wild-type and protein-deficient cell systems. Performance is benchmarked against experimental data from 21 cell lines and 18 radiation qualities. A model where resection-dependent and independent pathways are entirely separated can only reproduce experimental repair kinetics with additional restraints on end motion and protein recruitment. However, a model where the pathways are entwined was found to effectively fit without needing additional mechanisms. It has been shown that DaMaRiS is a useful tool when analysing the connections between resection-dependent and independent NHEJ repair pathways and robustly matches with experimental results from several sources.
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Affiliation(s)
- Yaping Qi
- School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026, China;
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (J.W.W.); (N.T.H.); (S.P.I.); (K.J.K.); (M.J.M.)
| | - John William Warmenhoven
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (J.W.W.); (N.T.H.); (S.P.I.); (K.J.K.); (M.J.M.)
- The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9PL, UK
| | - Nicholas Thomas Henthorn
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (J.W.W.); (N.T.H.); (S.P.I.); (K.J.K.); (M.J.M.)
- The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9PL, UK
| | - Samuel Peter Ingram
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (J.W.W.); (N.T.H.); (S.P.I.); (K.J.K.); (M.J.M.)
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester M13 9PL, UK
| | - Xie George Xu
- School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026, China;
| | - Karen Joy Kirkby
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (J.W.W.); (N.T.H.); (S.P.I.); (K.J.K.); (M.J.M.)
- The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9PL, UK
| | - Michael John Merchant
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (J.W.W.); (N.T.H.); (S.P.I.); (K.J.K.); (M.J.M.)
- The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9PL, UK
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Unravelling roles of error-prone DNA polymerases in shaping cancer genomes. Oncogene 2021; 40:6549-6565. [PMID: 34663880 PMCID: PMC8639439 DOI: 10.1038/s41388-021-02032-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/01/2021] [Accepted: 09/20/2021] [Indexed: 12/12/2022]
Abstract
Mutagenesis is a key hallmark and enabling characteristic of cancer cells, yet the diverse underlying mutagenic mechanisms that shape cancer genomes are not understood. This review will consider the emerging challenge of determining how DNA damage response pathways-both tolerance and repair-act upon specific forms of DNA damage to generate mutations characteristic of tumors. DNA polymerases are typically the ultimate mutagenic effectors of DNA repair pathways. Therefore, understanding the contributions of DNA polymerases is critical to develop a more comprehensive picture of mutagenic mechanisms in tumors. Selection of an appropriate DNA polymerase-whether error-free or error-prone-for a particular DNA template is critical to the maintenance of genome stability. We review different modes of DNA polymerase dysregulation including mutation, polymorphism, and over-expression of the polymerases themselves or their associated activators. Based upon recent findings connecting DNA polymerases with specific mechanisms of mutagenesis, we propose that compensation for DNA repair defects by error-prone polymerases may be a general paradigm molding the mutational landscape of cancer cells. Notably, we demonstrate that correlation of error-prone polymerase expression with mutation burden in a subset of patient tumors from The Cancer Genome Atlas can identify mechanistic hypotheses for further testing. We contrast experimental approaches from broad, genome-wide strategies to approaches with a narrower focus on a few hundred base pairs of DNA. In addition, we consider recent developments in computational annotation of patient tumor data to identify patterns of mutagenesis. Finally, we discuss the innovations and future experiments that will develop a more comprehensive portrait of mutagenic mechanisms in human tumors.
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