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Beh RC, Pitsillou E, Liang JJ, Hung A, Karagiannis TC. In silico investigation of DNA minor groove binding bibenzimidazoles in the context of UV A phototherapy. Phys Chem Chem Phys 2021; 24:112-121. [PMID: 34889929 DOI: 10.1039/d1cp04841d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The versatility of DNA minor groove binding bibenzimidazoles extends to applications in cancer therapy, beyond their typical use as DNA stains. In the context of UVA phototherapy, a series of halogenated analogues designated ortho-, meta-, and para-iodoHoechst have been investigated. Phototoxicity involves dehalogenation of the ligands following exposure to UVA light, resulting in the formation of a carbon-centred radical. While the cytotoxic mechanisms have been well established, the nature and severity of DNA damage induced by the ortho-, meta-, and para-iodoHoechst isomers requires clarification. Our aims were to measure and compare the binding constants of iodoHoechst analogues, and to determine the proximity of the carbon-centred radicals formed following photodehalogenation to the C1', C4', and C5' DNA carbons. We performed molecular docking studies, as well as classical molecular dynamics simulations to investigate the interactions of Hoechst ligands with DNA including a well-defined B-DNA dodecamer containing the high affinity AATT minor groove binding site. Docking highlighted the binding of Hoechst analogues to AATT regions in oligonucleotides, nucleosomes, and origami DNA helical bundles. Further, MD simulations demonstrated the stability of Hoechst ligands in the AATT-containing minor groove over microsecond trajectories. Our findings reiterate that the efficiency of dehalogenation per se, rather than the proximity of the carbon-centred radicals to the DNA backbone, is responsible for the extreme phototoxicity of the ortho- isomer compared to the meta- and para-iodoHoechst isomers. More generally, our analyses are in line with the potential utility of ortho-iodoHoechst in DNA-targeted phototherapy, particularly if combined with a cell-specific delivery system.
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Affiliation(s)
- Raymond C Beh
- Epigenomic Medicine, Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia. .,Department of Clinical Pathology, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Eleni Pitsillou
- Epigenomic Medicine, Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia. .,School of Science, College of Science, Engineering & Health, RMIT University, VIC 3001, Australia
| | - Julia J Liang
- Epigenomic Medicine, Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia. .,School of Science, College of Science, Engineering & Health, RMIT University, VIC 3001, Australia
| | - Andrew Hung
- School of Science, College of Science, Engineering & Health, RMIT University, VIC 3001, Australia
| | - Tom C Karagiannis
- Epigenomic Medicine, Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia. .,Department of Clinical Pathology, The University of Melbourne, Parkville, VIC 3052, Australia
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Howell RW. Advancements in the use of Auger electrons in science and medicine during the period 2015-2019. Int J Radiat Biol 2020; 99:2-27. [PMID: 33021416 PMCID: PMC8062591 DOI: 10.1080/09553002.2020.1831706] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/01/2020] [Accepted: 09/28/2020] [Indexed: 02/06/2023]
Abstract
Auger electrons can be highly radiotoxic when they are used to irradiate specific molecular sites. This has spurred basic science investigations of their radiobiological effects and clinical investigations of their potential for therapy. Focused symposia on the biophysical aspects of Auger processes have been held quadrennially. This 9th International Symposium on Physical, Molecular, Cellular, and Medical Aspects of Auger Processes at Oxford University brought together scientists from many different fields to review past findings, discuss the latest studies, and plot the future work to be done. This review article examines the research in this field that was published during the years 2015-2019 which corresponds to the period since the last meeting in Japan. In addition, this article points to future work yet to be done. There have been a plethora of advancements in our understanding of Auger processes. These advancements range from basic atomic and molecular physics to new ways to implement Auger electron emitters in radiopharmaceutical therapy. The highly localized doses of radiation that are deposited within a 10 nm of the decay site make them precision tools for discovery across the physical, chemical, biological, and medical sciences.
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Affiliation(s)
- Roger W Howell
- Division of Radiation Research, Department of Radiology, New Jersey Medical School, Rutgers University, Newark, NJ, USA
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Safavi-Naeini M, Chacon A, Guatelli S, Franklin DR, Bambery K, Gregoire MC, Rosenfeld A. Opportunistic dose amplification for proton and carbon ion therapy via capture of internally generated thermal neutrons. Sci Rep 2018; 8:16257. [PMID: 30390002 PMCID: PMC6215016 DOI: 10.1038/s41598-018-34643-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 10/22/2018] [Indexed: 12/11/2022] Open
Abstract
This paper presents Neutron Capture Enhanced Particle Therapy (NCEPT), a method for enhancing the radiation dose delivered to a tumour relative to surrounding healthy tissues during proton and carbon ion therapy by capturing thermal neutrons produced inside the treatment volume during irradiation. NCEPT utilises extant and in-development boron-10 and gadolinium-157-based drugs from the related field of neutron capture therapy. Using Monte Carlo simulations, we demonstrate that a typical proton or carbon ion therapy treatment plan generates an approximately uniform thermal neutron field within the target volume, centred around the beam path. The tissue concentrations of neutron capture agents required to obtain an arbitrary 10% increase in biological effective dose are estimated for realistic treatment plans, and compared to concentrations previously reported in the literature. We conclude that the proposed method is theoretically feasible, and can provide a worthwhile improvement in the dose delivered to the tumour relative to healthy tissue with readily achievable concentrations of neutron capture enhancement drugs.
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Affiliation(s)
- Mitra Safavi-Naeini
- Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia.
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, Australia.
| | - Andrew Chacon
- Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, Australia
| | - Susanna Guatelli
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, Australia
| | - Daniel R Franklin
- Faculty of Engineering & IT, University of Technology Sydney, Sydney, Australia
| | - Keith Bambery
- Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia
| | - Marie-Claude Gregoire
- Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, Australia
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, Australia
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Violet JA, Farrugia G, Skene C, White J, Lobachevsky P, Martin R. Triple targeting of Auger emitters using octreotate conjugated to a DNA-binding ligand and a nuclear localizing signal. Int J Radiat Biol 2016; 92:707-715. [DOI: 10.3109/09553002.2016.1157278] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- John A. Violet
- Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Gabriella Farrugia
- Molecular Radiation Biology Laboratory, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
- The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Colin Skene
- School of Chemistry and Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Jonathan White
- School of Chemistry and Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Pavel Lobachevsky
- Molecular Radiation Biology Laboratory, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
- The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Roger Martin
- Molecular Radiation Biology Laboratory, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
- The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria, Australia
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