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Khazaei Monfared Y, Heidari P, Klempner SJ, Mahmood U, Parikh AR, Hong TS, Strickland MR, Esfahani SA. DNA Damage by Radiopharmaceuticals and Mechanisms of Cellular Repair. Pharmaceutics 2023; 15:2761. [PMID: 38140100 PMCID: PMC10748326 DOI: 10.3390/pharmaceutics15122761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
DNA is an organic molecule that is highly vulnerable to chemical alterations and breaks caused by both internal and external factors. Cells possess complex and advanced mechanisms, including DNA repair, damage tolerance, cell cycle checkpoints, and cell death pathways, which together minimize the potentially harmful effects of DNA damage. However, in cancer cells, the normal DNA damage tolerance and response processes are disrupted or deregulated. This results in increased mutagenesis and genomic instability within the cancer cells, a known driver of cancer progression and therapeutic resistance. On the other hand, the inherent instability of the genome in rapidly dividing cancer cells can be exploited as a tool to kill by imposing DNA damage with radiopharmaceuticals. As the field of targeted radiopharmaceutical therapy (RPT) is rapidly growing in oncology, it is crucial to have a deep understanding of the impact of systemic radiation delivery by radiopharmaceuticals on the DNA of tumors and healthy tissues. The distribution and activation of DNA damage and repair pathways caused by RPT can be different based on the characteristics of the radioisotope and molecular target. Here we provide a comprehensive discussion of the biological effects of RPTs, with the main focus on the role of varying radioisotopes in inducing direct and indirect DNA damage and activating DNA repair pathways.
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Affiliation(s)
- Yousef Khazaei Monfared
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.K.M.); (P.H.); (U.M.)
| | - Pedram Heidari
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.K.M.); (P.H.); (U.M.)
| | - Samuel J. Klempner
- Division of Hematology-Oncology, Department of Medicine, Mass General Cancer Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (S.J.K.); (A.R.P.); (M.R.S.)
| | - Umar Mahmood
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.K.M.); (P.H.); (U.M.)
| | - Aparna R. Parikh
- Division of Hematology-Oncology, Department of Medicine, Mass General Cancer Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (S.J.K.); (A.R.P.); (M.R.S.)
| | - Theodore S. Hong
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA;
| | - Matthew R. Strickland
- Division of Hematology-Oncology, Department of Medicine, Mass General Cancer Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (S.J.K.); (A.R.P.); (M.R.S.)
| | - Shadi A. Esfahani
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; (Y.K.M.); (P.H.); (U.M.)
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Filosofov D, Kurakina E, Radchenko V. Potent candidates for Targeted Auger Therapy: Production and radiochemical considerations. Nucl Med Biol 2021; 94-95:1-19. [PMID: 33461040 DOI: 10.1016/j.nucmedbio.2020.12.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/18/2020] [Accepted: 12/03/2020] [Indexed: 12/14/2022]
Abstract
Targeted Auger Therapy represents great potential for the therapy of diseases which require a high degree of selectivity on the cellular level (e.g. for therapy of metastatic cancers). Due to their high Linear Energy Transfer (LET), Auger emitters, combined with selective biological systems which enable delivery of radionuclides close to the DNA of the targeting cell, can be extremely selective and powerful treatment tools. There are two main aspects associated with the development of efficient radiopharmaceuticals based on Auger Emitters: a) the availability of suitable Auger-emitting radionuclides for therapy and b) the design of targeting vectors which can deliver Auger emitters into/close to the nucleus. In the present review, we address the first aspect by defining important parameters for the selection of radionuclides for application to Targeted Auger Therapy and form a categorized list of the most promising radionuclides, their possible production routes, and their use in the synthesis of radiopharmaceuticals.
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Affiliation(s)
- Dmitry Filosofov
- Dzhelepov Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, Dubna, Moscow Region, Russian Federation
| | - Elena Kurakina
- Dzhelepov Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, Dubna, Moscow Region, Russian Federation; Department of High-Energy Chemistry and Radioecology, D. Mendeleev University of Chemical Technology of Russia, Moscow, Russian Federation
| | - Valery Radchenko
- Life Sciences Division, TRIUMF, Vancouver, BC, Canada; Chemistry Department, University of British Columbia, Vancouver, BC, Canada.
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Pereira E, do Quental L, Palma E, Oliveira MC, Mendes F, Raposinho P, Correia I, Lavrado J, Di Maria S, Belchior A, Vaz P, Santos I, Paulo A. Evaluation of Acridine Orange Derivatives as DNA-Targeted Radiopharmaceuticals for Auger Therapy: Influence of the Radionuclide and Distance to DNA. Sci Rep 2017; 7:42544. [PMID: 28211920 PMCID: PMC5304164 DOI: 10.1038/srep42544] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/09/2017] [Indexed: 01/01/2023] Open
Abstract
A new family of 99mTc(I)- tricarbonyl complexes and 125I-heteroaromatic compounds bearing an acridine orange (AO) DNA targeting unit was evaluated for Auger therapy. Characterization of the DNA interaction, performed with the non-radioactive Re and 127I congeners, confirmed that all compounds act as DNA intercalators. Both classes of compounds induce double strand breaks (DSB) in plasmid DNA but the extent of DNA damage is strongly dependent on the linker between the Auger emitter (99mTc or 125I) and the AO moiety. The in vitro evaluation was complemented with molecular docking studies and Monte Carlo simulations of the energy deposited at the nanometric scale, which corroborated the experimental data. Two of the tested compounds, 125I-C5 and 99mTc-C3, place the corresponding radionuclide at similar distances to DNA and produce comparable DSB yields in plasmid and cellular DNA. These results provide the first evidence that 99mTc can induce DNA damage with similar efficiency to that of 125I, when both are positioned at comparable distances to the double helix. Furthermore, the high nuclear retention of 99mTc-C3 in tumoral cells suggests that 99mTc-labelled AO derivatives are more promising for the design of Auger-emitting radiopharmaceuticals than the 125I-labelled congeners.
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Affiliation(s)
- Edgar Pereira
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - Letícia do Quental
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - Elisa Palma
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal.,Centro Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1049-001 Lisboa, Portugal
| | - Maria Cristina Oliveira
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - Filipa Mendes
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - Paula Raposinho
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - Isabel Correia
- Centro Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1049-001 Lisboa, Portugal
| | - João Lavrado
- iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Salvatore Di Maria
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - Ana Belchior
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - Pedro Vaz
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - Isabel Santos
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - António Paulo
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
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Lobachevsky P, Clark GR, Pytel PD, Leung B, Skene C, Andrau L, White JM, Karagiannis T, Cullinane C, Lee BQ, Stuchbery A, Kibedi T, Hicks RJ, Martin RF. Strand breakage by decay of DNA-bound 124I provides a basis for combined PET imaging and Auger endoradiotherapy. Int J Radiat Biol 2016; 92:686-697. [PMID: 26902391 DOI: 10.3109/09553002.2015.1136852] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Purpose DNA ligands labelled with 125I induce cytotoxic DNA double-strand breaks (DSB), suggesting a potential for Auger endoradiotherapy. Since the 60-day half-life of 125I is suboptimal for therapy, we have investigated another Auger-emitter 124I, with shorter half-life (4.18 days), and the additional feature of positron-emission, enabling positron emission tomography (PET) imaging. The purpose of this study was to compare the two radionuclides on the basis of DNA DSB per decay. Materials and methods Using a 124I- (or 125I)-labelled minor groove binding DNA ligand, we investigated DNA breakage using the plasmid DNA assay. Biodistribution of the conjugate of the labelled ligand with transferrin was investigated in nude mice bearing a K562 human lymphoma xenograft. Results The probability of DSB per decay was 0.58 and 0.85 for 124I and 125I, respectively, confirming the therapeutic potential of the former. The crystal structure of the ligand DNA complex shows the iodine atom deep within the minor groove, consistent with the high efficiency of induced damage. Biodistribution studies, including PET imaging, showed distinctive results for the conjugate, compared to the free ligand and transferrin, consistent with receptor-mediated delivery of the ligand. Conclusions Conjugation of 124I-labelled DNA ligands to tumor targeting peptides provides a feasible strategy for Auger endoradiotherapy, with the advantage of monitoring tumor targeting by PET imaging.
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Affiliation(s)
- Pavel Lobachevsky
- a Molecular Radiation Biology Laboratory , Peter MacCallum Cancer Centre , Melbourne.,b The Sir Peter MacCallum Department of Oncology , The University of Melbourne , Melbourne , Australia
| | - George R Clark
- c School of Chemical Sciences , The University of Auckland , New Zealand
| | - Patrycja D Pytel
- c School of Chemical Sciences , The University of Auckland , New Zealand
| | - Brenda Leung
- d School of Chemistry and Bio-21 Molecular Science and Biotechnology Institute , University of Melbourne , Australia
| | - Colin Skene
- d School of Chemistry and Bio-21 Molecular Science and Biotechnology Institute , University of Melbourne , Australia
| | - Laura Andrau
- d School of Chemistry and Bio-21 Molecular Science and Biotechnology Institute , University of Melbourne , Australia
| | - Jonathan M White
- d School of Chemistry and Bio-21 Molecular Science and Biotechnology Institute , University of Melbourne , Australia
| | - Tom Karagiannis
- a Molecular Radiation Biology Laboratory , Peter MacCallum Cancer Centre , Melbourne
| | - Carleen Cullinane
- b The Sir Peter MacCallum Department of Oncology , The University of Melbourne , Melbourne , Australia.,e Cancer Research Division , Peter MacCallum Cancer Centre , Melbourne
| | - Boon Q Lee
- f Department of Nuclear Physics, Research School of Physics and Engineering , Australian National University , Canberra
| | - Andrew Stuchbery
- f Department of Nuclear Physics, Research School of Physics and Engineering , Australian National University , Canberra
| | - Tibor Kibedi
- f Department of Nuclear Physics, Research School of Physics and Engineering , Australian National University , Canberra
| | - Rodney J Hicks
- b The Sir Peter MacCallum Department of Oncology , The University of Melbourne , Melbourne , Australia.,g Centre for Molecular Imaging, Peter MacCallum Cancer Centre , Melbourne , VIC , Australia
| | - Roger F Martin
- a Molecular Radiation Biology Laboratory , Peter MacCallum Cancer Centre , Melbourne.,b The Sir Peter MacCallum Department of Oncology , The University of Melbourne , Melbourne , Australia.,d School of Chemistry and Bio-21 Molecular Science and Biotechnology Institute , University of Melbourne , Australia
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Balagurumoorthy P, Xu X, Wang K, Adelstein SJ, Kassis AI. Effect of distance between decaying (125)I and DNA on Auger-electron induced double-strand break yield. Int J Radiat Biol 2012; 88:998-1008. [PMID: 22732063 DOI: 10.3109/09553002.2012.706360] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To determine the possible effects of (125)I-to-DNA distance on the magnitude and mechanism of Auger-electron induced-double-strand break (DSB) production. MATERIALS AND METHODS We have synthesized a series of (125)I-labeled Hoechst (H) derivatives ((125)IE-H, (125)IB-H, (125)I-C(8)-H and (125)I-C(12)-H). While all four molecules share a common DNA minor groove binding bis-benzimidazole motif, they are designed to position (125)I at varying distances from the DNA helix. Each Hoechst derivative was incubated at 4°C in phosphate buffered saline (PBS) together with supercoiled (SC) (3)H-pUC19 plasmid DNA (ratio 3:1) ± the •OH scavenger dimethyl sulfoxide (DMSO) (0.2 M). Aliquots were analyzed on agarose gels over time and DSB yields per decay of (125)I atom were determined. Docking of the iodinated compounds on a DNA molecule was carried out to determine the distance between the iodine atom and the central axis of DNA. RESULTS In the absence of DMSO, the results show that the DSB yields decrease monotonically as the (125)I atom is distanced - by 10.5 Å to 13.9 Å - from the DNA helix ((125)IEH: 0.52 ± 0.01; (125)IB-H: 0.24 ± 0.03; (125)I-C(8)-H: 0.18 ± 0.02; (125)I-C(12)-H: 0.10 ± 0.00). In the presence of DMSO, DSB yields for (125)IEH (0.49 ± 0.02) and (125)IB-H (0.26 ± 0.04) remain largely unchanged indicating that DSB are entirely produced by direct effects. Strikingly, (125)I-C(8)-H or (125)I-C(12)-H, did not produce detectable DSB in the presence of DMSO under similar conditions suggesting when (125)I atom is positioned > 12 Å from the DNA, DSB are entirely produced by indirect effects. CONCLUSION These results suggest that at a critical distance between the (125)I atom and the DNA helix, DSB production switches from an 'all' direct to an 'all' indirect mechanism, the latter situation being comparable to the decay of (125)I free in solution. These experimental findings were correlated with theoretical expectations based on microdosimetry.
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Balagurumoorthy P, Adelstein SJ, Kassis AI. Novel method for quantifying radiation-induced single-strand-break yields in plasmid DNA highlights 10-fold discrepancy. Anal Biochem 2011; 417:242-6. [PMID: 21741945 DOI: 10.1016/j.ab.2011.06.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/16/2011] [Accepted: 06/17/2011] [Indexed: 11/17/2022]
Abstract
The widely used agarose gel electrophoresis method for assessing radiation-induced single-strand-break (SSB) yield in plasmid DNA involves measurement of the fraction of relaxed-circular (C) form that migrates independently from the intact supercoiled (SC) form. We rationalized that this method may underestimate the SSB yield since the position of the relaxed-circular form is not altered when the number of SSB per DNA molecule is >1. To overcome this limitation, we have developed a novel method that directly probes and quantifies SSBs. Supercoiled (3)H-pUC19 plasmid samples were irradiated with γ-rays, alkali-denatured, dephosphorylated, and kinated with γ-[(32)P]ATP, and the DNA-incorporated (32)P activities were used to quantify the SSB yields per DNA molecule, employing a standard curve generated using DNA molecules containing a known number of SSBs. The same irradiated samples were analyzed by agarose gel and SSB yields were determined by conventional methods. Comparison of the data demonstrated that the mean SSB yield per plasmid DNA molecule of [21.2±0.59]×10(-2)Gy(-1) as measured by direct probing is ~10-fold higher than that obtained from conventional gel-based methods. These findings imply that the SSB yields inferred from agarose gels need reevaluation, especially when they were utilized in the determination of radiation risk.
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Jiang Y, Rabbi M, Mieczkowski PA, Marszalek PE. Separating DNA with different topologies by atomic force microscopy in comparison with gel electrophoresis. J Phys Chem B 2010; 114:12162-5. [PMID: 20799746 DOI: 10.1021/jp105603k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Atomic force microscopy, which is normally used for DNA imaging to gain qualitative results, can also be used for quantitative DNA research, at a single-molecular level. Here, we evaluate the performance of AFM imaging specifically for quantifying supercoiled and relaxed plasmid DNA fractions within a mixture, and compare the results with the bulk material analysis method, gel electrophoresis. The advantages and shortcomings of both methods are discussed in detail. Gel electrophoresis is a quick and well-established quantification method. However, it requires a large amount of DNA, and needs to be carefully calibrated for even slightly different experimental conditions for accurate quantification. AFM imaging is accurate, in that single DNA molecules in different conformations can be seen and counted. When used carefully with necessary correction, both methods provide consistent results. Thus, AFM imaging can be used for DNA quantification, as an alternative to gel electrophoresis.
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Affiliation(s)
- Yong Jiang
- School of Chemistry and Chemical Engineering, Southeast University, Jiangning, Nanjing, Jiangsu 211189, People's Republic of China.
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Terrissol M, Peudon A, Kümmerle E, Pomplun E. On the biological efficiency of I-123 and I-125 decay on the molecular level. Int J Radiat Biol 2009; 84:1063-8. [DOI: 10.1080/09553000802552150] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Lobachevsky PN, White J, Leung M, Skene C, White J, Martin RF. Plasmid breakage by (125)I-labelled DNA ligands: effect of DNA-iodine atom distance on breakage efficiency. Int J Radiat Biol 2009; 84:991-1000. [PMID: 19061123 DOI: 10.1080/09553000802478091] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE The aim of the study is to establish the relationship between the efficiency of DNA double-stranded breakage by (125)I-labelled DNA ligands and the distance from the decaying atom to the helical axis. MATERIALS AND METHODS Two new iodinated minor groove binding ligands were synthesized which, on the basis of molecular modelling studies, place the iodine atom at different distances from the DNA helical axis (namely 7.4 and 11.2 A degrees ). Plasmid DNA breakage experiments, in both buffer-only and buffer + 2M dimethylsulfoxide (DMSO), were used to determine the efficiency of induction of internal double-stranded breaks (DSB) of the two new ligands, as well as that for (125)I-Hoechst 33258, which is characterized by a helical axis-iodine atom distance of 9.1 A degrees . RESULTS The results showed a progressive decrease in the efficiency of DNA DSB induction with the axis-iodine atom distance, for both incubation conditions. The distance-damage relationship was somewhat steeper than previously predicted from the theoretical studies by Humm and Charlton, based on radical-mediated damage. Another distinctive trend was revealed by comparison of breakage efficiency with and without DMSO. The extent of DMSO protection increased significantly with DNA-iodine distance. CONCLUSIONS The steeper than predicted decrease in DSB induction with DNA-iodine distance is consistent with a substantial contribution to DNA breakage of the charge neutralization effect (arising from the transient positive charge left on the daughter Te atom), and the expectation that this contribution would be very dependent on the distance of the site of hole injection from the base-pair pi-stack. An important caveat to the results and conclusions is the need to confirm the estimated helical axis-iodine distances with X-ray crystallography studies, and for further exemplification with a more extensive collection of DNA ligands.
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Affiliation(s)
- Pavel N Lobachevsky
- Trescowthick Research Laboratories, Peter MacCallum Cancer Centre, Melbourne, Australia
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Abstract
PURPOSE The extreme radiotoxicity of Auger electrons and their exquisite capacity to irradiate specific molecular sites has prompted scientists to extensively investigate their radiobiological effects. Their efforts have been punctuated by quadrennial international symposia that have focused on biophysical aspects of Auger processes. The latest meeting, the 6th International Symposium on Physical, Molecular, Cellular, and Medical Aspects of Auger Processes, was held 5-6 July 2007 at Harvard Medical School in Boston, Massachusetts, USA. This article provides a review of the research in this field that was published during the years 2004-2007, the period that has elapsed since the previous meeting. CONCLUSION The field has advanced considerably. A glimpse of the potential of this unique form of ionizing radiation to contribute to future progress in a variety of fields of study is proffered.
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Affiliation(s)
- Roger W Howell
- Department of Radiology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA.
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Jiang Y, Rabbi M, Kim M, Ke C, Lee W, Clark RL, Mieczkowski PA, Marszalek PE. UVA generates pyrimidine dimers in DNA directly. Biophys J 2009; 96:1151-8. [PMID: 19186150 DOI: 10.1016/j.bpj.2008.10.030] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 10/31/2008] [Indexed: 10/21/2022] Open
Abstract
There is increasing evidence that UVA radiation, which makes up approximately 95% of the solar UV light reaching the Earth's surface and is also commonly used for cosmetic purposes, is genotoxic. However, in contrast to UVC and UVB, the mechanisms by which UVA produces various DNA lesions are still unclear. In addition, the relative amounts of various types of UVA lesions and their mutagenic significance are also a subject of debate. Here, we exploit atomic force microscopy (AFM) imaging of individual DNA molecules, alone and in complexes with a suite of DNA repair enzymes and antibodies, to directly quantify UVA damage and reexamine its basic mechanisms at a single-molecule level. By combining the activity of endonuclease IV and T4 endonuclease V on highly purified and UVA-irradiated pUC18 plasmids, we show by direct AFM imaging that UVA produces a significant amount of abasic sites and cyclobutane pyrimidine dimers (CPDs). However, we find that only approximately 60% of the T4 endonuclease V-sensitive sites, which are commonly counted as CPDs, are true CPDs; the other 40% are abasic sites. Most importantly, our results obtained by AFM imaging of highly purified native and synthetic DNA using T4 endonuclease V, photolyase, and anti-CPD antibodies strongly suggest that CPDs are produced by UVA directly. Thus, our observations contradict the predominant view that as-yet-unidentified photosensitizers are required to transfer the energy of UVA to DNA to produce CPDs. Our results may help to resolve the long-standing controversy about the origin of UVA-produced CPDs in DNA.
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Affiliation(s)
- Yong Jiang
- Center for Biologically Inspired Materials and Material Systems, Duke University, Durham, North Carolina, USA
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Morgenroth A, Deisenhofer S, Glatting G, Kunkel FHG, Dinger C, Zlatopolskiy B, Vogg ATJ, Kull T, Reske SN. Preferential tumor targeting and selective tumor cell cytotoxicity of 5-[131/125I]iodo-4'-thio-2'-deoxyuridine. Clin Cancer Res 2009; 14:7311-9. [PMID: 19010846 DOI: 10.1158/1078-0432.ccr-08-0907] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Auger electron emitting radiopharmaceuticals are attractive for targeted nanoirradiation therapy, provided that DNA of malignant cells is selectively addressed. Here, we examine 5-[123/125/131I]iodo-4'-thio-2'-deoxyuridine (ITdU) for targeting DNA in tumor cells in a HL60 xenograft severe combined immunodeficient mouse model. EXPERIMENTAL DESIGN Thymidine kinase and phosphorylase assays were done to determine phosphorylation and glycosidic bond cleavage of ITdU, respectively. The biodistribution and DNA incorporation of ITdU were determined in severe combined immunodeficient mice bearing HL60 xenografts receiving pretreatment with 5-fluoro-2'-deoxyuridine (FdUrd). Organ tissues were dissected 0.5, 4, and 24 h after radioinjection and uptake of [131I]ITdU (%ID/g tissue) was determined. Cellular distribution of [125I]ITdU was imaged by microautoradiography. Apoptosis and expression of the proliferation marker Ki-67 were determined by immunohistologic staining using corresponding paraffin tissue sections. RESULTS ITdU is phosphorylated by thymidine kinase 1 and stable toward thymidylate phosphatase-mediated glycosidic bond cleavage. Thymidylate synthase-mediated deiodination of [123/125/131I]ITdU was inhibited with FdUrd. Pretreatment with FdUrd increased preferentially tumor uptake of ITdU resulting in favorable tumor-to-normal tissue ratios and tumor selectivity. ITdU was exclusively localized within the nucleus and incorporated into DNA. In FdUrd-pretreated animals, we found in more than 90% of tumor cells apoptosis induction 24 h postinjection of ITdU, indicating a highly radiotoxic effect in tumor cells but not in cells of major proliferating tissues. CONCLUSION ITdU preferentially targets DNA in proliferating tumor cells and leads to apoptosis provided that the thymidylate synthase is inhibited.
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Sharma KKK, Milligan JR, Bernhard WA. Multiplicity of DNA single-strand breaks produced in pUC18 exposed to the direct effects of ionizing radiation. Radiat Res 2008; 170:156-62. [PMID: 18666814 DOI: 10.1667/rr1277.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Accepted: 04/30/2008] [Indexed: 11/03/2022]
Abstract
The transition of plasmid DNA from a supercoiled to an open circle conformation, as detected by gel electrophoresis, affords an extraordinarily sensitive method for detecting single-strand breaks (SSBs), one measure of deoxyribose damage. To determine the yield of SSBs, G(ssb), by this method, it is commonly assumed that Poisson statistics apply such that, on average, one SSB occurs per supercoiled plasmid lost. For the direct effect, at a large enough plasmid size, this assumption may be invalid. In this report, the assumption that one SSB occurs per pUC18 plasmid (2686 bp) is tested by measuring free base release (fbr), which is also a measure of deoxyribose damage in films prepared under controlled relative humidity so as to produce known levels of DNA hydration. The level of DNA hydration, Gamma, is expressed in mol water/mol nucleotide. The yield of free base release, G(fbr), was measured by HPLC after exposure of the films to 70 kV X rays and subsequent dissolution in water. It is well known that damage in deoxyribose leads to SSBs and free base release. Based on known mechanisms, there exists a close correspondence between free base release and SSBs, i.e., G(fbr) congruent with G(ssb). Following this assumption, the SSB multiplicity, m(ssb), was determined, where m(ssb) was defined as the mean number of SSBs per supercoiled plasmid lost. The yield of lost supercoil was determined previously (S. Purkayastha et al., J. Phys. Chem. B 110, 26286-26291, 2006). We found that m(ssb) = 1.4 +/- 0.2 at Gamma = 2.5 and m(ssb) = 2.8 +/- 0.5 to 3.1 +/- 0.5 at Gamma = 22.5, indicating that the assumption of one SSB per lost supercoil is not likely to hold for a 2686-bp plasmid exposed to the direct effect. In addition, an increase in G(fbr), upon stepping from Gamma = 2.5 to Gamma = 22.5, was paralleled by an increase in the yield of trapped deoxyribose radicals, G(dRib)(fr), also measured previously. As a consequence, the shortfall between SSBs and trapped radicals, G(diff) = G(ssb) - G(dRib)(fr), remained relatively constant at 90-110 nmol/J. The lack of change between the two extremes of hydration is in keeping with the suggestion that non-radical species, such as doubly oxidized deoxyribose, are responsible for the shortfall.
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Affiliation(s)
- Kiran Kumar K Sharma
- Department of Biochemistry and Biophysics, University of Rochester, 575 Elmwood Avenue, Rochester, NY 14642, USA
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Ke C, Jiang Y, Mieczkowski PA, Muramoto GG, Chute JP, Marszalek PE. Nanoscale detection of ionizing radiation damage to DNA by atomic force microscopy. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:288-294. [PMID: 18247386 DOI: 10.1002/smll.200700527] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The detection and quantification of ionizing radiation damage to DNA at a single-molecule level by atomic force microscopy (AFM) is reported. The DNA damage-detection technique combining supercoiled plasmid relaxation assay with AFM imaging is a direct and quantitative approach to detect gamma-ray-induced single- and double-strand breaks in DNA, and its accuracy and reliability are validated through a comparison with traditional agarose gel electrophoresis. In addition, the dependence of radiation-induced single-strand breaks on plasmid size and concentration at a single-molecule level in a low-dose (1 Gy) and low-concentration range (0.01 ng microL(-1)-10 ng microL(-1)) is investigated using the AFM-based damage-detection assay. The results clearly show that the number of single-strand breaks per DNA molecule is linearly proportional to the plasmid size and inversely correlated to the DNA concentration. This assay can also efficiently detect DNA damage in highly dilute samples (0.01 ng microL(-1)), which is beyond the capability of traditional techniques. AFM imaging can uniquely supplement traditional techniques for sensitive measurements of damage to DNA by ionizing radiation.
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Affiliation(s)
- Changhong Ke
- Center for Biologically Inspired Materials and Material Systems and Department of Mechanical, Engineering and Materials Science, Duke University, Durham, NC 27708, USA
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Jiang Y, Ke C, Mieczkowski PA, Marszalek PE. Detecting ultraviolet damage in single DNA molecules by atomic force microscopy. Biophys J 2007; 93:1758-67. [PMID: 17483180 PMCID: PMC1948057 DOI: 10.1529/biophysj.107.108209] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report detection and quantification of ultraviolet (UV) damage in DNA at a single molecule level by atomic force microscopy (AFM). By combining the supercoiled plasmid relaxation assay with AFM imaging, we find that high doses of medium wave ultraviolet (UVB) and short wave ultraviolet (UVC) light not only produce cyclobutane pyrimidine dimers (CPDs) as reported but also cause significant DNA degradation. Specifically, 12.5 kJ/m(2) of UVC and 165 kJ/m(2) of UVB directly relax 95% and 78% of pUC18 supercoiled plasmids, respectively. We also use a novel combination of the supercoiled plasmid assay with T4 Endonuclease V treatment of irradiated plasmids and AFM imaging of their relaxation to detect damage caused by low UVB doses, which on average produced approximately 0.5 CPD per single plasmid. We find that at very low UVB doses, the relationship between the number of CPDs and UVB dose is almost linear, with 4.4 CPDs produced per Mbp per J/m(2) of UVB radiation. We verified these AFM results by agarose gel electrophoresis separation of UV-irradiated and T4 Endonuclease V treated plasmids. Our AFM and gel electrophoresis results are consistent with the previous result obtained using other traditional DNA damage detection methods. We also show that damage detection assay sensitivity increases with plasmid size. In addition, we used photolyase to mark the sites of UV lesions in supercoiled plasmids for detection and quantification by AFM, and these results were found to be consistent with the results obtained by the plasmid relaxation assay. Our results suggest that AFM can supplement traditional methods for high resolution measurements of UV damage to DNA.
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Affiliation(s)
- Yong Jiang
- Center for Biologically Inspired Materials and Material Systems and Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
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16
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Buchegger F, Perillo-Adamer F, Dupertuis YM, Delaloye AB. Auger radiation targeted into DNA: a therapy perspective. Eur J Nucl Med Mol Imaging 2006; 33:1352-63. [PMID: 16896663 DOI: 10.1007/s00259-006-0187-2] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 05/29/2006] [Accepted: 06/09/2006] [Indexed: 11/24/2022]
Abstract
BACKGROUND Auger electron emitters that can be targeted into DNA of tumour cells represent an attractive systemic radiation therapy goal. In the situation of DNA-associated decay, the high linear energy transfer (LET) of Auger electrons gives a high relative biological efficacy similar to that of alpha particles. In contrast to alpha radiation, however, Auger radiation is of low toxicity when decaying outside the cell nucleus, as in cytoplasm or outside cells during blood transport. The challenge for such therapies is the requirement to target a high percentage of all cancer cells. An overview of Auger radiation therapy approaches of the past decade shows several research directions and various targeting vehicles. The latter include hormones, peptides, halogenated nucleotides, oligonucleotides and internalising antibodies. DISCUSSION Here, we will discuss the basic principles of Auger electron therapy as compared with vector-guided alpha and beta radiation. We also review some radioprotection issues and briefly present the main advantages and disadvantages of the different targeting modalities that are under investigation.
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Affiliation(s)
- Franz Buchegger
- Service of Nuclear Medicine, University Hospital of Lausanne CHUV, Rue du Bugnon 46, 1011 Lausanne, Switzerland.
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Balagurumoorthy P, Chen K, Bash RC, Adelstein SJ, Kassis AI. Mechanisms Underlying Production of Double-Strand Breaks in Plasmid DNA after Decay of125I-Hoechst. Radiat Res 2006; 166:333-44. [PMID: 16881734 DOI: 10.1667/rr3591.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Previously, the kinetics of strand break production by (125)I-labeled m-iodo-p-ethoxyHoechst 33342 ((125)IEH) in supercoiled (SC) plasmid DNA had demonstrated that approximately 1 DSB is produced per (125)I decay both in the presence and absence of the hydroxyl radical scavenger DMSO. In these experiments, an (125)IEH:DNA molar ratio of 42:1 was used. We now hypothesize that this DSB yield (but not the SSB yield) may be an overestimate due to subsequent decays occurring in any of the 41 (125)IEH molecules still bound to nicked (N) DNA. To test our hypothesis, (125)IEH was incubated with SC pUC19 plasmids ((125)IEH:DNA ratio of approximately 3:1) and the SSB and DSB yields were quantified after the decay of (125)I. As predicted, the number of DSBs produced per (125)I decay is one-half that reported previously ( approximately 0.5 compared to approximately 1, +/- DMSO) whereas the number of SSBs ( approximately 3/(125)I decay) is similar to that obtained previously ( approximately 90% are generated by OH radicals). Direct visualization by atomic force microscopy confirms formation of L and N DNA after (125)IEH decays in SC DNA and supports the strand break yields reported. These findings indicate that although SSB production is independent of the number of (125)IEH bound to DNA, the DSB yield can be augmented erroneously by (125)I decays occurring in N DNA. Further analysis indicates that 17% of SSBs and 100% of DSBs take place within the plasmid molecule in which an (125)IEH molecule decays, whereas 83% of SSBs are formed in neighboring plasmid DNA molecules.
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Grafström G, Jönsson BA, El Hassan AM, Tennvall J, Strand SE. Rat testis as a radiobiological in vivo model for radionuclides. RADIATION PROTECTION DOSIMETRY 2006; 118:32-42. [PMID: 16046556 DOI: 10.1093/rpd/nci328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The radiobiological effect of intracellularly localised radionuclides emitting low energy electrons (Auger electrons) has received much attention. Most in vivo studies reported have been performed in the mouse testis. We have investigated the rat testis as an in vivo radiobiological model, with sperm-head survival, testis weight loss and also alteration in the blood plasma hormone levels of FSH and LH as radiobiological endpoints. Validation of the rat testis model was evaluated by using mean absorbed doses of up to 10 Gy from intratesticularly (i.t.) injected (111)In oxine or local X-ray irradiation. Biokinetics of the i.t. injected radionuclide was analysed by scintillation camera imaging and used in the absorbed dose estimation. By the analysis of the autoradiographs, the activity distribution was revealed. Cell fractionation showed (111)In to be mainly associated with the cell nuclei. External irradiations were monitored by thermoluminescence dosimeters. The sperm-head survival was the most sensitive radiobiological parameter correlated to the mean absorbed dose, with a D(37) of 2.3 Gy for (111)In oxine and 1.3 Gy for X rays. The levels of plasma pituitary gonadal hormones FSH and LH were elevated for absorbed doses >7.7 Gy. This investigation shows that the radiobiological model based on the rat testis has several advantages compared with the previously commonly used mouse testis model. The model is appropriate for further investigations of basic phenomena such as radiation geometry, intracellular kinetics and heterogeneity, crucial for an understanding of the biological effect of low-energy electrons.
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Affiliation(s)
- G Grafström
- Departament of Medical Radiation Physics, Lund University, S-221 85 Lund, Sweden.
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Edel S, Terrissol M, Peudon A, Kümmerle E, Pomplun E. Computer simulation of strand break yields in plasmid pBR322: DNA damage following 125I decay. RADIATION PROTECTION DOSIMETRY 2006; 122:136-40. [PMID: 17185311 DOI: 10.1093/rpd/ncl453] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
This paper presents results of (125)I effects on plasmid pBR322 in aqueous solution, simulating the complete transport of Auger and X rays up to the chemical phase. In addition to new sampling algorithms, new electronic cross sections are included. Simulations were carried out both with (125)I, bound to plasmid, or free, in its vicinity. The influence of the hydroxyl radical scavenger dimethyl sulfoxyde (DMSO) has also been tested, underlying that, in naked DNA, double strand breaks (caused by the decay of bound (125)I) are mainly due to direct hits. The calculated yields of relaxation events (RE) and linearization events (LE) show good agreement with experimental ones: when (125)I is bound to the plasmid pBR322, 0.16 RE and 0.83 LE per decay (without DMSO) are then observed. Then, when 2 mol DMSO is added, RE and LE probabilities become 0.22 and 0.76. The very light differences with those from literature could arise from experimental conditions.
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Affiliation(s)
- S Edel
- CPAT, Bât. 3R2, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex 9, France
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Lobachevsky PN, Martin RF. DNA Breakage by Decay of Auger Electron Emitters: Experiments with123I-iodoHoechst 33258 and Plasmid DNA. Radiat Res 2005; 164:766-73. [PMID: 16296882 DOI: 10.1667/rr3469.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The Auger electron-emitting isotope 123I is of interest in the context of potential exploitation of Auger electron emitters in radioimmunotherapy. The efficiency of induction of cytotoxic lesions by decay of DNA-associated 125I, the prototype Auger electron emitter, is well established, but its long half-life (60 days) is a limitation. However, the advantage of the much shorter half-life of 123I (13.2 h) might be outweighed by its "weaker" Auger electron cascade with an average of 8-11 Auger electrons, compared to about 15-21 electrons for 125I. Accordingly, the efficiency of DNA breakage for DNA-associated 123I was investigated by incubation of 123I-iodoHoechst 33258 with plasmid DNA. The efficiency of double-strand break induction by decay of 123I was 0.62 compared to 0.82 per decay of 125I in the same experimental system. In the presence of dimethylsulfoxide, the values were 0.54 and 0.65 for decay of 123I and 125I, respectively. The results also showed that at a very low ligand/plasmid molar ratio (<1), the majority of cleavage seemed to occur at a particular site on the plasmid molecule, indicating preferential binding of the 123I-ligand to a unique site or a cluster of neighboring sites.
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Affiliation(s)
- Pavel N Lobachevsky
- Trescowthick Research Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
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Lobachevsky PN, Martin RF. Plasmid DNA breakage by decay of DNA-associated auger emitters: experiments with 123I/125I-iodoHoechst 33258. Int J Radiat Biol 2005; 80:915-20. [PMID: 15764402 DOI: 10.1080/09553000400017754] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE The Auger emitting isotope 123I has a much shorter half-life (13.2 hours), than 125I, the prototype Auger emitter. Monte Carlo simulations and cell culture studies indicate that decay of 123I covalently incorporated into DNA is about half as effective as 125I in terms of DNA breakage and cytotoxicity. The aim of the present study is to assess the DNA breakage efficacy of 123I that is non-covalently associated with DNA, using the minor groove binding ligand iodoHoechst 33258. MATERIALS AND METHODS Plasmid (pBR322) DNA was incubated with mixtures of [123I]- and [125I]-iodoHoechst 33258, and DNA double strand breakage (DSB) assessed by assaying the relative amounts of intact, relaxed and linear plasmid forms separated by agarose gel electrophoresis. This "double-label" approach provides a measure of the ratio of probabilities of DSB formation per decay for these two isotopes, with much higher precision than comparing the absolute probabilities for the individual isotopes, principally because it avoids the requirement to accurately determine the fraction of bound ligand. RESULTS Our results indicate that the ratio of DSB probability per decay of 123I to that of 125I is 0.63 +/- 0.03. The ratio does not change much with addition of dimethyl sulfoxide (DMSO) to the incubation mixture--0.65 +/- 0.03. This ratio agrees well with the relative efficiency of the two isotopes reported in theoretical and experimental studies, using various endpoints. CONCLUSIONS In considering the possible exploitation of the Auger effect in cancer therapy, the modest decrease in DNA breakage efficacy for 123I compared to 125I might be more than compensated for by the advantage of the much shorter half-life. The 60-day half-life of 125I imposes severe limitations in terms of radiation protection.
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Affiliation(s)
- Pavel N Lobachevsky
- Research Laboratories, Peter MacCallum Cancer Centre, St Andrew's Place, East Melbourne, Victoria 3002, Australia
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