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Ameixa J, Bald I. Unraveling the Complexity of DNA Radiation Damage Using DNA Nanotechnology. Acc Chem Res 2024. [PMID: 38780304 DOI: 10.1021/acs.accounts.4c00121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
ConspectusRadiation cancer therapies use different ionizing radiation qualities that damage DNA molecules in tumor cells by a yet not completely understood plethora of mechanisms and processes. While the direct action of the radiation is significant, the byproducts of the water radiolysis, mainly secondary low-energy electrons (LEEs, <20 eV) and reactive oxygen species (ROS), can also efficiently cause DNA damage, in terms of DNA strand breakage or DNA interstrand cross-linking. As a result, these types of DNA damage evolve into mutations hindering DNA replication, leading to cancer cell death. Concomitant chemo-radiotherapy explores the addition of radiosensitizing therapeutics commonly targeting DNA, such as platinum derivatives and halogenated nucleosides, to enhance the harmful effects of ionizing radiation on the DNA molecule. Further complicating the landscape of DNA damage are secondary structures such as G-quadruplexes occurring in telomeric DNA. These structures protect DNA from radiation damage, rendering them as promising targets for new and more selective cancer radiation treatments, rather than targeting linear DNA. However, despite extensive research, there is no single paradigm approach to understanding the mysterious way in which ionizing radiation causes DNA damage. This is due to the multidisciplinary nature of the field of research, which deals with multiple levels of biological organization, from the molecular building blocks of life toward cells and organisms, as well as with complex multiscale radiation-induced effects. Also, intrinsic DNA features, such as DNA topology and specific oligonucleotide sequences, strongly influence its response to damage from ionizing radiation. In this Account, we present our studies focused on the absolute quantification of photon- and low-energy electron-induced DNA damage in strategically selected target DNA sequences. Our methodology involves using DNA origami nanostructures, specifically the Rothemund triangle, as a platform to expose DNA sequences to either low-energy electrons or vacuum-ultraviolet (VUV, <15 eV) photons and subsequent atomic force microscopy (AFM) analysis. Through this approach, the effects of the DNA sequence, incorporation of halogenated radiosensitizers, DNA topology, and the radiation quality on radiation-induced DNA strand breakage have been systematically assessed and correlated with fundamental photon- and electron-driven mechanisms underlying DNA radiation damage. At lower energies, these mechanisms include dissociative electron attachment (DEA), where electrons attach to DNA molecules causing strand breaks, and dissociative photoexcitation of DNA. Additionally, further dissociative processes such as photoionization and electron impact contribute to the complex cascade of DNA damage events induced by ionizing radiation. We expect that emerging DNA origami-based approaches will lead to a paradigm shift in research fields associated with DNA damage and suggest future directions, which can foster the development of technological applications in nanomedicine, e.g., optimized cancer treatments or the molecular design of optimized radiosensitizing therapeutics.
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Affiliation(s)
- João Ameixa
- Institute of Chemistry, Hybrid Nanostructures, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
- Centre of Physics and Technological Research (CEFITEC), Department of Physics, NOVA School of Science and Technology, University NOVA of Lisbon, Campus de Caparica 2829-516, Portugal
| | - Ilko Bald
- Institute of Chemistry, Hybrid Nanostructures, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
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2
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Saqib M, Arthur-Baidoo E, Izadi F, Szczyrba A, Datta M, Demkowicz S, Rak J, Denifl S. Dissociative Electron Attachment to 5-Iodo-4-thio-2'-deoxyuridine: A Potential Radiosensitizer of Hypoxic Cells. J Phys Chem Lett 2023; 14:8948-8955. [PMID: 37769041 PMCID: PMC10578351 DOI: 10.1021/acs.jpclett.3c02219] [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: 08/09/2023] [Accepted: 09/20/2023] [Indexed: 09/30/2023]
Abstract
In the search for effective radiosensitizers for tumor cells, halogenated uracils have attracted more attention due to their large cross section for dissociation upon the attachment of low-energy electrons. In this study, we investigated dissociative electron attachment (DEA) to 5-iodo-4-thio-2'-deoxyuridine, a potential radiosensitizer using a crossed electron-molecule beam experiment coupled with quadrupole mass spectrometry. The experimental results were supported by calculations on the threshold energies of formed anions and transition state calculations. We show that low-energy electrons with kinetic energies near 0 eV may effectively decompose the molecule upon DEA. The by far most abundant anion observed corresponds to the iodine anion (I-). Due to the associated bond cleavage, a radical site is formed at the C5 position, which may initiate strand break formation if the molecule is incorporated into a DNA strand. Our results reflect the conclusion from previous radiolysis studies with the title compound, suggesting its potential as a radiosensitizer.
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Affiliation(s)
- Muhammad Saqib
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
- Center
for Molecular Biosciences Innsbruck, Universität
Innsbruck, Technikerstraße
25, A-6020 Innsbruck, Austria
| | - Eugene Arthur-Baidoo
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
- Center
for Molecular Biosciences Innsbruck, Universität
Innsbruck, Technikerstraße
25, A-6020 Innsbruck, Austria
| | - Farhad Izadi
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
- Center
for Molecular Biosciences Innsbruck, Universität
Innsbruck, Technikerstraße
25, A-6020 Innsbruck, Austria
| | - Adrian Szczyrba
- Laboratory
of Biological Sensitizers, Department of Physical Chemistry, Faculty
of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Magdalena Datta
- Laboratory
of Biological Sensitizers, Department of Physical Chemistry, Faculty
of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Sebastian Demkowicz
- Department
of Organic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Janusz Rak
- Laboratory
of Biological Sensitizers, Department of Physical Chemistry, Faculty
of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Stephan Denifl
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
- Center
for Molecular Biosciences Innsbruck, Universität
Innsbruck, Technikerstraße
25, A-6020 Innsbruck, Austria
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3
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Pintea M, Mason N, Peiró-Franch A, Clark E, Samanta K, Glessi C, Schmidtke IL, Luxford T. Dissociative electron attachment to gold(I)-based compounds: 4,5-dichloro-1,3-diethyl-imidazolylidene trifluoromethyl gold(I). Front Chem 2023; 11:1028008. [PMID: 37405247 PMCID: PMC10315492 DOI: 10.3389/fchem.2023.1028008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 06/01/2023] [Indexed: 07/06/2023] Open
Abstract
With the use of proton-NMR and powder XRD (XRPD) studies, the suitability of specific Au-focused electron beam induced deposition (FEBID) precursors has been investigated with low electron energy, structure, excited states and resonances, structural crystal modifications, flexibility, and vaporization level. 4,5-Dichloro-1,3-diethyl-imidazolylidene trifluoromethyl gold(I) is a compound that is a uniquely designed precursor to meet the needs of focused electron beam-induced deposition at the nanostructure level, which proves its capability in creating high purity structures, and its growing importance in other AuImx and AuClnB (where x and n are the number of radicals, B = CH, CH3, or Br) compounds in the radiation cancer therapy increases the efforts to design more suitable bonds in processes of SEM (scanning electron microscopy) deposition and in gas-phase studies. The investigation performed of its powder shape using the XRPD XPERT3 panalytical diffractometer based on CoKα lines shows changes to its structure with change in temperature, level of vacuum, and light; the sensitivity of this compound makes it highly interesting in particular to the radiation research. Used in FEBID, though its smaller number of C, H, and O atoms has lower levels of C contamination in the structures and on the surface, it replaces these bonds with C-Cl and C-N bonds that have lower bond-breaking energy. However, it still needs an extra purification step in the deposition process, either H2O, O2, or H jets.
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Affiliation(s)
- Maria Pintea
- School of Physical Sciences, University of Kent, Canterbury, United Kingdom
| | - Nigel Mason
- School of Physical Sciences, University of Kent, Canterbury, United Kingdom
| | - Anna Peiró-Franch
- School of Physical Sciences, University of Kent, Canterbury, United Kingdom
| | - Ewan Clark
- School of Physical Sciences, University of Kent, Canterbury, United Kingdom
| | - Kushal Samanta
- School of Physical Sciences, University of Kent, Canterbury, United Kingdom
| | | | | | - Thomas Luxford
- Department of Chemistry, J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czechia
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4
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Izadi F, Szczyrba A, Datta M, Ciupak O, Demkowicz S, Rak J, Denifl S. Electron-Induced Decomposition of 5-Bromo-4-thiouracil and 5-Bromo-4-thio-2'-deoxyuridine: The Effect of the Deoxyribose Moiety on Dissociative Electron Attachment. Int J Mol Sci 2023; 24:ijms24108706. [PMID: 37240053 DOI: 10.3390/ijms24108706] [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: 03/24/2023] [Revised: 04/28/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
When modified uridine derivatives are incorporated into DNA, radical species may form that cause DNA damage. This category of molecules has been proposed as radiosensitizers and is currently being researched. Here, we study electron attachment to 5-bromo-4-thiouracil (BrSU), a uracil derivative, and 5-bromo-4-thio-2'-deoxyuridine (BrSdU), with an attached deoxyribose moiety via the N-glycosidic (N1-C) bond. Quadrupole mass spectrometry was used to detect the anionic products of dissociative electron attachment (DEA), and the experimental results were supported by quantum chemical calculations performed at the M062X/aug-cc-pVTZ level of theory. Experimentally, we found that BrSU predominantly captures low-energy electrons with kinetic energies near 0 eV, though the abundance of bromine anions was rather low compared to a similar experiment with bromouracil. We suggest that, for this reaction channel, proton-transfer reactions in the transient negative ions limit the release of bromine anions.
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Affiliation(s)
- Farhad Izadi
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Adrian Szczyrba
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Magdalena Datta
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Olga Ciupak
- Department of Organic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Sebastian Demkowicz
- Department of Organic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Janusz Rak
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Stephan Denifl
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
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5
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Chomicz-Mańka L, Czaja A, Falkiewicz K, Zdrowowicz M, Biernacki K, Demkowicz S, Izadi F, Arthur-Baidoo E, Denifl S, Zhu Z, Tufekci BA, Harris R, Bowen KH, Rak J. Intramolecular Proton Transfer in the Radical Anion of Cytidine Monophosphate Sheds Light on the Sensitivities of Dry vs Wet DNA to Electron Attachment-Induced Damage. J Am Chem Soc 2023; 145:9059-9071. [PMID: 37040588 PMCID: PMC10141262 DOI: 10.1021/jacs.3c00591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
Single-strand breaks (SSBs) induced via electron attachment were previously observed in dry DNA under ultrahigh vacuum (UHV), while hydrated electrons were found not able to induce this DNA damage in an aqueous solution. To explain these findings, crossed electron-molecular beam (CEMB) and anion photoelectron spectroscopy (aPES) experiments coupled to density functional theory (DFT) modeling were used to demonstrate the fundamental importance of proton transfer (PT) in radical anions formed via electron attachment. Three molecular systems were investigated: 5'-monophosphate of 2'-deoxycytidine (dCMPH), where PT in the electron adduct is feasible, and two ethylated derivatives, 5'-diethylphosphate and 3',5'-tetraethyldiphosphate of 2'-deoxycytidine, where PT is blocked due to substitution of labile protons with the ethyl residues. CEMB and aPES experiments confirmed the cleavage of the C3'/C5'-O bond as the main dissociation channel related to electron attachment in the ethylated derivatives. In the case of dCMPH, however, electron attachment (in the aPES experiments) yielded its parent (intact) radical anion, dCMPH-, suggesting that its dissociation was inhibited. The aPES-measured vertical detachment energy of the dCMPH- was found to be 3.27 eV, which agreed with its B3LYP/6-31++G(d,p)-calculated value and implied that electron-induced proton transfer (EIPT) had occurred during electron attachment to the dCMPH model nucleotide. In other words, EIPT, subduing dissociation, appeared to be somewhat protective against SSB. While EIPT is facilitated in solution compared to the dry environment, the above findings are consistent with the stability of DNA against hydrated electron-induced SSB in solution versus free electron-induced SSB formation in dry DNA.
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Affiliation(s)
- Lidia Chomicz-Mańka
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Anna Czaja
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Karina Falkiewicz
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Magdalena Zdrowowicz
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Karol Biernacki
- Department of Organic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Sebastian Demkowicz
- Department of Organic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Farhad Izadi
- Institut für Ionenphysik und Angewandte Physik and Center for Biomolecular Sciences Innsbruck, Leopold-Franzens Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Eugene Arthur-Baidoo
- Institut für Ionenphysik und Angewandte Physik and Center for Biomolecular Sciences Innsbruck, Leopold-Franzens Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Stephan Denifl
- Institut für Ionenphysik und Angewandte Physik and Center for Biomolecular Sciences Innsbruck, Leopold-Franzens Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Zhaoguo Zhu
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Burak Ahmet Tufekci
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Rachel Harris
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kit H Bowen
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Janusz Rak
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
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Narayanan S J J, Tripathi D, Verma P, Adhikary A, Dutta AK. Secondary Electron Attachment-Induced Radiation Damage to Genetic Materials. ACS OMEGA 2023; 8:10669-10689. [PMID: 37008102 PMCID: PMC10061531 DOI: 10.1021/acsomega.2c06776] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 02/20/2023] [Indexed: 06/19/2023]
Abstract
Reactions of radiation-produced secondary electrons (SEs) with biomacromolecules (e.g., DNA) are considered one of the primary causes of radiation-induced cell death. In this Review, we summarize the latest developments in the modeling of SE attachment-induced radiation damage. The initial attachment of electrons to genetic materials has traditionally been attributed to the temporary bound or resonance states. Recent studies have, however, indicated an alternative possibility with two steps. First, the dipole-bound states act as a doorway for electron capture. Subsequently, the electron gets transferred to the valence-bound state, in which the electron is localized on the nucleobase. The transfer from the dipole-bound to valence-bound state happens through a mixing of electronic and nuclear degrees of freedom. In the presence of aqueous media, the water-bound states act as the doorway state, which is similar to that of the presolvated electron. Electron transfer from the initial doorway state to the nucleobase-bound state in the presence of bulk aqueous media happens on an ultrafast time scale, and it can account for the decrease in DNA strand breaks in aqueous environments. Analyses of the theoretically obtained results along with experimental data have also been discussed.
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Affiliation(s)
- Jishnu Narayanan S J
- Department
of Chemistry, Indian Institute of Technology
Bombay, Powai, Mumbai 400076, India
| | - Divya Tripathi
- Department
of Chemistry, Indian Institute of Technology
Bombay, Powai, Mumbai 400076, India
| | - Pooja Verma
- Department
of Chemistry, Indian Institute of Technology
Bombay, Powai, Mumbai 400076, India
| | - Amitava Adhikary
- Department
of Chemistry, Oakland University, 146 Library Drive, Rochester, Michigan 48309, United States
| | - Achintya Kumar Dutta
- Department
of Chemistry, Indian Institute of Technology
Bombay, Powai, Mumbai 400076, India
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Falkiewicz K, Kozak W, Zdrowowicz M, Spisz P, Chomicz-Mańka L, Torchala M, Rak J. Why 6-Iodouridine Cannot Be Used as a Radiosensitizer of DNA Damage? Computational and Experimental Studies. J Phys Chem B 2023; 127:2565-2574. [PMID: 36893332 PMCID: PMC10041638 DOI: 10.1021/acs.jpcb.3c00548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Previous density functional theory (DFT) studies on 6-brominated pyrimidine nucleosides suggest that 6-iodo-2'-deoxyuridine (6IdU) should act as a better radiosensitizer than its 5-iodosubstituted 2'-deoxyuridine analogue. In this work, we show that 6IdU is unstable in an aqueous solution. Indeed, a complete disappearance of the 6IdU signal was observed during its isolation by reversed-phase high-performance liquid chromatography (RP-HPLC). As indicated by the thermodynamic characteristics for the SN1-type hydrolysis of 6IdU obtained at the CAM-B3LYP/DGDZVP++ level and the polarizable continuum model (PCM) of water, 6-iodouracil (6IU) was already released quantitatively at ambient temperatures. The simulation of the hydrolysis kinetics demonstrated that a thermodynamic equilibrium was reached within seconds for the title compound. To assess the reliability of the calculations carried out, we synthesized 6-iodouridine (6IUrd), which was, unlike 6IdU, sufficiently stable in an aqueous solution at room temperature. The activation barrier for the N-glycosidic bond dissociation in 6IUrd was estimated experimentally using an Arrhenius plot. The stabilities in water calculated for 6IdU, 6IUrd, and 5-iodo-2'-deoxyuridine (5IdU) could be explained by the electronic and steric effects of the 2'-hydroxy group present in the ribose moiety. Our studies highlight the issue of the hydrolytic stability of potentially radiosensitizing nucleotides which, besides having favorable dissociative electron attachment (DEA) characteristics, must be stable in water to have any practical application.
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Affiliation(s)
- Karina Falkiewicz
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Witold Kozak
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Magdalena Zdrowowicz
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Paulina Spisz
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
- Laboratory of Intermolecular Interactions, Department of Bioinorganic Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Lidia Chomicz-Mańka
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Mieczyslaw Torchala
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Janusz Rak
- Laboratory of Biological Sensitizers, Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
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Ouyang L, Lin H, Zhuang P, Shao Y, Khosravifarsani M, Guérin B, Zheng Y, Sanche L. DNA radiosensitization by terpyridine-platinum: damage induced by 5 and 10 eV transient anions. NANOSCALE 2023; 15:3230-3242. [PMID: 36722902 DOI: 10.1039/d2nr05403e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Chemoradiation therapy (CRT), which combines a chemotherapeutic drug with ionizing radiation (IR), is the most common cancer treatment. At the molecular level, the binding of Pt-drugs to DNA sensitizes cancer cells to IR, mostly by increasing the damage induced by secondary low-energy (0-20 eV) electrons (LEEs). We investigate such enhancements by binding terpyridine-platinum (Tpy-Pt) to supercoiled plasmid DNA. Fifteen nanometer thick films of Tpy-Pt-DNA complexes in a molar ratio of 5 : 1 were irradiated with monoenergetic electrons of 5 and 10 eV, which principally attach to the DNA bases to form transient anions (TAs) decaying into a multitude of bond-breaking channels. At both energies, the effective yields of crosslinks (CLs), base damage (BD) related CLs, single and double strand breaks (SSBs and DSBs), non-DSB-cluster lesions, loss of supercoiled configuration and base lesions are 6.5 ± 1.5, 8.8± 3.0, 88 ± 11, 5.3 ± 1.3, 9.6 ± 2.2, 106 ± 17, 189 ± 31 × 10-15 per electron per molecule, and 11.9 ± 2.6, 19.9 ± 4.4, 128 ± 18, 7.7 ± 3.0, 13.4 ± 3.9, 144 ± 19, 229 ± 42 × 10-15 per electron per molecule, respectively. DNA damage increased 1.2-4.2-fold due to Tpy-Pt, the highest being for BD-related CLs. These enhancements are slightly higher than those obtained by the conventional Pt-drugs cisplatin, carboplatin and oxaliplatin, apart from BD-related CLs, which are about 3 times higher. Enhancements are related to the strong perturbation of the DNA helix by Tpy-Pt, its high dipole moment and its favorable binding to guanine (G), all of which increase bond-breaking via TA formation. In CRT, Tpy-Pt could considerably enhance crosslinking within genomic DNA and between DNA and other components of the nucleus, causing roadblocks to replication and transcription, particularly within telomeres, where it binds preferentially within G-quadruplexes.
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Affiliation(s)
- Liangde Ouyang
- State Key Laboratory of Photocatalysis on Energy and Environment, Faculty of Chemistry, Fuzhou University, Fuzhou 350116, P.R. China
| | - Hong Lin
- State Key Laboratory of Photocatalysis on Energy and Environment, Faculty of Chemistry, Fuzhou University, Fuzhou 350116, P.R. China
| | - Puxiang Zhuang
- State Key Laboratory of Photocatalysis on Energy and Environment, Faculty of Chemistry, Fuzhou University, Fuzhou 350116, P.R. China
| | - Yu Shao
- State Key Laboratory of Photocatalysis on Energy and Environment, Faculty of Chemistry, Fuzhou University, Fuzhou 350116, P.R. China
| | - Meysam Khosravifarsani
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4.
| | - Brigitte Guérin
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4.
| | - Yi Zheng
- State Key Laboratory of Photocatalysis on Energy and Environment, Faculty of Chemistry, Fuzhou University, Fuzhou 350116, P.R. China
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4.
| | - Léon Sanche
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4.
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9
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Potential of HF and CO2 loss through dissociative electron attachment to increase radiosensitizers reactivity; case study on pentafluorobenzoic acid. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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10
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Arthur-Baidoo E, Ončák M, Denifl S. Electron attachment to fluorodeoxyglucose: Dissociation dynamics in a molecule of near-zero electron affinity. J Chem Phys 2022; 157:074301. [PMID: 35987575 DOI: 10.1063/5.0101726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Fluorodeoxyglucose (FDG) is a glucose derivative with fluorine at the C2 position. The molecule containing the radioactive F-18 isotope is well known from its application in positron emission tomography as a radiotracer in tumor examination. In the stable form with the F-19 isotope, FDG was proposed as a potential radiosensitizer. Since reduction processes may be relevant in radiosensitization, we investigated low-energy electron attachment to FDG with a crossed electron-molecule beam experiment and with quantum chemical calculations as well as molecular dynamics at elevated temperatures to reveal statistical dissociation. We experimentally find that the susceptibility of FDG to low-energy electrons is relatively low. The calculations indicate that upon attachment of an electron with a kinetic energy of ∼0 eV, only dipole-bound states are accessible, which agrees with the weak ion yields observed in the experiment. The temporary negative ions formed upon electron attachment to FDG may decay by a large variety of dissociation reactions. The major fragmentation channels include H2O, HF, and H2 dissociation, accompanied by ring opening.
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Affiliation(s)
- Eugene Arthur-Baidoo
- Institut fücr Ionenphysik und Angewandte Physik, Leopold-Franzens Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Milan Ončák
- Institut fücr Ionenphysik und Angewandte Physik, Leopold-Franzens Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Stephan Denifl
- Institut fücr Ionenphysik und Angewandte Physik, Leopold-Franzens Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
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11
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Low-Energy Electron Induced Reactions in Metronidazole at Different Solvation Conditions. Pharmaceuticals (Basel) 2022; 15:ph15060701. [PMID: 35745620 PMCID: PMC9227036 DOI: 10.3390/ph15060701] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/27/2022] [Accepted: 05/30/2022] [Indexed: 12/16/2022] Open
Abstract
Metronidazole belongs to the class of nitroimidazole molecules and has been considered as a potential radiosensitizer for radiation therapy. During the irradiation of biological tissue, secondary electrons are released that may interact with molecules of the surrounding environment. Here, we present a study of electron attachment to metronidazole that aims to investigate possible reactions in the molecule upon anion formation. Another purpose is to elucidate the effect of microhydration on electron-induced reactions in metronidazole. We use two crossed electron/molecular beam devices with the mass-spectrometric analysis of formed anions. The experiments are supported by quantum chemical calculations on thermodynamic properties such as electron affinities and thresholds of anion formation. For the single molecule, as well as the microhydrated condition, we observe the parent radical anion as the most abundant product anion upon electron attachment. A variety of fragment anions are observed for the isolated molecule, with NO2- as the most abundant fragment species. NO2- and all other fragment anions except weakly abundant OH- are quenched upon microhydration. The relative abundances suggest the parent radical anion of metronidazole as a biologically relevant species after the physicochemical stage of radiation damage. We also conclude from the present results that metronidazole is highly susceptible to low-energy electrons.
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12
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Cui X, Zhao Y, Zhang C, Meng Q. Nitro rotation tuned dissociative electron attachment upon targeted radiosensitizer 4-substituted Z bases. Phys Chem Chem Phys 2022; 24:10356-10364. [PMID: 35438101 DOI: 10.1039/d2cp00351a] [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
In this work, a set of new potential radiation sensitizers (4-substituted Z-bases: 4XZ, X = F, Cl, Br, and I) are designed based on the artificial 6-amino-5-nitro-3-(1'-β-D-2'-deoxyribofuranosyl)-2(1H)-pyridone (Z), which can selectively bind to breast cancer cells. The calculated electron affinities in water solution show that the halogenated Z-bases are efficient electron acceptors which possess significant electron-withdrawing characters following the order of 4XZ > Z ≫ U. To ensure the effective electron attachment induced dissociation, we constructed the energy profiles related to the X-C bond cleavage of neutral and anionic bases. The results show that the X-C bond becomes relatively weak after the electron attachment. In particular, the electron induced dehalogenations of (4BrZ)- and (4IZ)- are low-barrier and exothermic, which support a high radiosensitivity. Furthermore, we characterized the vibrational excitation effect on the dissociative electron attachment, which demonstrates that the charge distribution can be regulated by the rotation-induced structural distortion accompanied by the electron localization on the nitro group. Also examined is the influence of base pairing on the dehalogenation, which is not only conducive to the electron-driven dissociation but is also beneficial to the stabilization of related products. The current study suggests 4BrZ and 4IZ can be regarded as potential targeted radiosensitizers with possible applications in reducing the side effects in radiotherapy.
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Affiliation(s)
- Xixi Cui
- College of Physics and Electronics, Shandong Normal University, Jinan 250358, Shandong, China.
| | - Yu Zhao
- College of Physics and Electronics, Shandong Normal University, Jinan 250358, Shandong, China.
| | - Changzhe Zhang
- College of Physics and Electronics, Shandong Normal University, Jinan 250358, Shandong, China.
| | - Qingtian Meng
- College of Physics and Electronics, Shandong Normal University, Jinan 250358, Shandong, China.
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13
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HF Formation through Dissociative Electron Attachment-A Combined Experimental and Theoretical Study on Pentafluorothiophenol and 2-Fluorothiophenol. Int J Mol Sci 2022; 23:ijms23052430. [PMID: 35269573 PMCID: PMC8910151 DOI: 10.3390/ijms23052430] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 02/05/2023] Open
Abstract
In chemoradiation therapy, dissociative electron attachment (DEA) may play an important role with respect to the efficiency of the radiosensitizers used. The rational tailoring of such radiosensitizers to be more susceptive to DEA may thus offer a path to increase their efficiency. Potentially, this may be achieved by tailoring rearrangement reactions into the DEA process such that these may proceed at low incident electron energies, where DEA is most effective. Favorably altering the orbital structure of the respective molecules through substitution is another path that may be taken to promote dissociation up on electron capture. Here we present a combined experimental and theoretical study on DEA in relation to pentafluorothiophenol (PFTP) and 2-fluorothiophenol (2-FTP). We investigate the thermochemistry and dynamics of neutral HF formation through DEA as means to lower the threshold for dissociation up on electron capture to these compounds, and we explore the influence of perfluorination on their orbital structure. Fragment ion yield curves are presented, and the thermochemical thresholds for the respective DEA processes are computed as well as the minimum energy paths for HF formation up on electron capture and the underlying orbital structure of the respective molecular anions. We show that perfluorination of the aromatic ring in these compounds plays an important role in enabling HF formation by further lowering the threshold for this process and through favorable influence on the orbital structure, such that DEA is promoted. We argue that this approach may offer a path for tailoring new and efficient radiosensitizers.
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14
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Liu C, Zheng Y, Sanche L. Damage Induced to DNA and Its Constituents by 0-3 eV UV Photoelectrons †. Photochem Photobiol 2021; 98:546-563. [PMID: 34767635 DOI: 10.1111/php.13559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/07/2021] [Indexed: 11/28/2022]
Abstract
The complex physical and chemical interactions between DNA and 0-3 eV electrons released by UV photoionization can lead to the formation of various lesions such as base modifications and cleavage, crosslinks and single strand breaks. Furthermore, in the presence of platinum chemotherapeutic agents, these electrons can cause clustered lesions, including double strand breaks. We explain the mechanisms responsible for these damages via the production 0-3 eV electrons by UVC radiation, and by UV photons of any wavelengths, when they are produced by photoemission from nanoparticles lying within about 10 nm from DNA. We review experimental evidence showing that a single 0-3 eV electron can produce these damages. The foreseen benefits UV-irradiation of nanoparticles targeted to the cell nucleus are mentioned in the context of cancer therapy, as well as the potential hazards to human health when they are present in cells.
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Affiliation(s)
- Chaochao Liu
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou, China
| | - Yi Zheng
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou, China
| | - Léon Sanche
- Département de Médecine Nucléaire et Radiobiologie et Centre de Recherche Clinique, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, QC, Canada
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15
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Ziegler P, Pelc A, Arthur-Baidoo E, Ameixa J, Ončák M, Denifl S. Negative ion formation and fragmentation upon dissociative electron attachment to the nicotinamide molecule. RSC Adv 2021; 11:32425-32434. [PMID: 35495526 PMCID: PMC9041917 DOI: 10.1039/d1ra06083j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/13/2021] [Indexed: 12/20/2022] Open
Abstract
Nicotinamide (C6H6N2O) is a biologically relevant molecule. This compound has several important roles related to the anabolic and metabolic processes that take place in living organisms. It is also used as a radiosensitizer in tumor therapy. As a result of the interaction of high-energy radiation with matter, low-energy electrons are also released, which can also interact with other molecules, forming several types of ions. In the present investigation, dissociative electron attachment to C6H6N2O has been studied in a crossed electron-molecular beams experiment in the electron energy range of about 0-15 eV. In the experiment, six anionic species were detected: C6H5N2O-, C5H4N-, NCO-, O-/NH2 -, and CN-, with NCO- being the most prominent anion. We also provide detailed computational results regarding the energetic thresholds and pathways of the respective dissociative electron attachment (DEA) channels. The experimental results are compared with the theoretical ones and on this basis, the possible DEA reactions for the formation of anions at a given resonance energy were assigned as well as the generation of neutrals fragments such as pyridine and its several derivatives and radicals are predicted. The pyridine ring seems to stay intact during the DEA process.
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Affiliation(s)
- Patrick Ziegler
- Institute for Ion Physics and Applied Physics, University of Innsbruck Technikerstrasse 25 6020 Innsbruck Austria
| | - Andrzej Pelc
- Maria Curie-Skłodowska University, Department of Biophysics, Mass Spectrometry Laboratory Pl. M. C.-Skłodowskiej 1 20-031 Lublin Poland
| | - Eugene Arthur-Baidoo
- Institute for Ion Physics and Applied Physics, University of Innsbruck Technikerstrasse 25 6020 Innsbruck Austria
| | - Joao Ameixa
- Institute for Ion Physics and Applied Physics, University of Innsbruck Technikerstrasse 25 6020 Innsbruck Austria .,Centre of Physics and Technological Research, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa 2829-516 Caparica Portugal
| | - Milan Ončák
- Institute for Ion Physics and Applied Physics, University of Innsbruck Technikerstrasse 25 6020 Innsbruck Austria
| | - Stephan Denifl
- Institute for Ion Physics and Applied Physics, University of Innsbruck Technikerstrasse 25 6020 Innsbruck Austria
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16
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Ma J, Bahry T, Denisov SA, Adhikary A, Mostafavi M. Quasi-Free Electron-Mediated Radiation Sensitization by C5-Halopyrimidines. J Phys Chem A 2021; 125:7967-7975. [PMID: 34470211 PMCID: PMC8448956 DOI: 10.1021/acs.jpca.1c05974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Substitution of the thymidine moiety in DNA by C5-substituted halogenated thymidine analogues causes significant augmentation of radiation damage in living cells. However, the molecular pathway involved in such radiosensitization process has not been clearly elucidated to date in solution at room temperature. So far, low-energy electrons (LEEs; 0-20 eV) under vacuum condition and solvated electrons (esol-) in solution are shown to produce the σ-type C5-centered pyrimidine base radical through dissociative electron attachment involving carbon-halogen bond breakage. Formation of this σ-type radical and its subsequent reactions are proposed to cause cellular radiosensitization. Here, we report time-resolved measurements at room temperature, showing that a radiation-produced quasi-free electron (eqf-) in solution promptly breaks the C5-halogen bond in halopyrimidines forming the σ-type C5 radical via an excited transient anion radical. These results demonstrate the importance of ultrafast reactions of eqf-, which are extremely important in chemistry, physics, and biology, including tumor radiochemotherapy.
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Affiliation(s)
- Jun Ma
- Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, P. R. China
| | - Teseer Bahry
- Department of Nuclear Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, P. R. China
- Institut de Chimie Physique, UMR 8000 CNRS, Bât. 349, Université Paris-Saclay; 91405, Orsay, Cedex, France
| | - Sergey A. Denisov
- Institut de Chimie Physique, UMR 8000 CNRS, Bât. 349, Université Paris-Saclay; 91405, Orsay, Cedex, France
| | - Amitava Adhikary
- Department of Chemistry, Oakland University, 146 Library Drive, Rochester, MI - 48309, United States
| | - Mehran Mostafavi
- Institut de Chimie Physique, UMR 8000 CNRS, Bât. 349, Université Paris-Saclay; 91405, Orsay, Cedex, France
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17
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Sedmidubská B, Luxford TFM, Kočišek J. Electron attachment to isolated and microhydrated favipiravir. Phys Chem Chem Phys 2021; 23:21501-21511. [PMID: 34382983 DOI: 10.1039/d1cp02686k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Electron attachment and its equivalent in complex environments, single-electron reduction, are important in many biological processes. Here, we experimentally study the electron attachment to favipiravir, a well-known antiviral agent. Electron attachment spectroscopy is used to explore the energetics of associative (AEA) and dissociative (DEA) electron attachment to isolated favipiravir. AEA dominates the interaction and the yields of the fragment anions after DEA are an order of magnitude lower than that of the parent anion. DEA primary proceeds via decomposition of the CONH2 functional group, which is supported by reaction threshold calculations using ab initio methods. Mass spectrometry of small favipiravir-water clusters demonstrates that a lot of energy is transferred to the solvent upon electron attachment. The energy gained upon electron attachment, and the high stability of the parent anion were previously suggested as important properties for the action of several electron-affinic radiosensitizers. If any of these mechanisms cause synergism in chemo-radiation therapy, favipiravir could be repurposed as a radiosensitizer.
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Affiliation(s)
- Barbora Sedmidubská
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic. and Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Břehová 7, 11519 Prague, Czech Republic
| | - Thomas F M Luxford
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic.
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic.
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18
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Gao Y, Zheng Y, Sanche L. Low-Energy Electron Damage to Condensed-Phase DNA and Its Constituents. Int J Mol Sci 2021; 22:7879. [PMID: 34360644 PMCID: PMC8345953 DOI: 10.3390/ijms22157879] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/30/2021] [Accepted: 06/30/2021] [Indexed: 11/18/2022] Open
Abstract
The complex physical and chemical reactions between the large number of low-energy (0-30 eV) electrons (LEEs) released by high energy radiation interacting with genetic material can lead to the formation of various DNA lesions such as crosslinks, single strand breaks, base modifications, and cleavage, as well as double strand breaks and other cluster damages. When crosslinks and cluster damages cannot be repaired by the cell, they can cause genetic loss of information, mutations, apoptosis, and promote genomic instability. Through the efforts of many research groups in the past two decades, the study of the interaction between LEEs and DNA under different experimental conditions has unveiled some of the main mechanisms responsible for these damages. In the present review, we focus on experimental investigations in the condensed phase that range from fundamental DNA constituents to oligonucleotides, synthetic duplex DNA, and bacterial (i.e., plasmid) DNA. These targets were irradiated either with LEEs from a monoenergetic-electron or photoelectron source, as sub-monolayer, monolayer, or multilayer films and within clusters or water solutions. Each type of experiment is briefly described, and the observed DNA damages are reported, along with the proposed mechanisms. Defining the role of LEEs within the sequence of events leading to radiobiological lesions contributes to our understanding of the action of radiation on living organisms, over a wide range of initial radiation energies. Applications of the interaction of LEEs with DNA to radiotherapy are briefly summarized.
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Affiliation(s)
- Yingxia Gao
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350116, China;
| | - Yi Zheng
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350116, China;
| | - Léon Sanche
- Département de Médecine Nucléaire et Radiobiologie et Centre de Recherche Clinique, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada;
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19
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Muftakhov M, Shchukin P, Khatymov R. Thymidine and stavudine molecules in reactions with low-energy electrons. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109464] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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20
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Mendes M, Kossoski F, Lozano AI, Pereira-da-Silva J, Rodrigues R, Ameixa J, Jones NC, Hoffmann SV, Ferreira da Silva F. Excited States of Bromopyrimidines Probed by VUV Photoabsorption Spectroscopy and Theoretical Calculations. Int J Mol Sci 2021; 22:6460. [PMID: 34208711 PMCID: PMC8235550 DOI: 10.3390/ijms22126460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/10/2021] [Accepted: 06/12/2021] [Indexed: 11/16/2022] Open
Abstract
We report absolute photoabsorption cross sections for gas-phase 2- and 5-bromopyrimidine in the 3.7-10.8 eV energy range, in a joint theoretical and experimental study. The measurements were carried out using high-resolution vacuum ultraviolet synchrotron radiation, with quantum chemical calculations performed through the nuclear ensemble approach in combination with time-dependent density functional theory, along with additional Franck-Condon Herzberg-Teller calculations for the first absorption band (3.7-4.6 eV). The cross sections of both bromopyrimidines are very similar below 7.3 eV, deviating more substantially from each other at higher energies. In the 7.3-9.0 eV range where the maximum cross-section is found, a single and broad band is observed for 5-bromopyrimidine, while more discernible features appear in the case of 2-bromopyrimidine. Several π* ← π transitions account for the most intense bands, while weaker ones are assigned to transitions involving the nitrogen and bromine lone pairs, the antibonding σ*Br orbital, and the lower-lying Rydberg states. A detailed comparison with the available photo-absorption data of bromobenzene is also reported. We have found significant differences regarding the main absorption band, which is more peaked in bromobenzene, becoming broader and shifting to higher energies in both bromopyrimidines. In addition, there is a significant suppression of vibrational structures and of Rydberg states in the pair of isomers, most noticeably for 2-bromopyrimidine.
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Affiliation(s)
- Mónica Mendes
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
| | - Fábris Kossoski
- Laboratoire de Chimie et Physique Quantiques (UMR 5626), Université de Toulouse, CNRS, UPS, CEDEX 09, 31062 Toulouse, France
| | - Ana I. Lozano
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
| | - João Pereira-da-Silva
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
| | - Rodrigo Rodrigues
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
| | - João Ameixa
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
| | - Nykola C. Jones
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark; (N.C.J.); (S.V.H.)
| | - Søren V. Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark; (N.C.J.); (S.V.H.)
| | - Filipe Ferreira da Silva
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
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21
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Arthur-Baidoo E, Ameixa J, Ončák M, Denifl S. Ring-Selective Fragmentation in the Tirapazamine Molecule upon Low-Energy Electron Attachment. Int J Mol Sci 2021; 22:ijms22063159. [PMID: 33808887 PMCID: PMC8003736 DOI: 10.3390/ijms22063159] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 01/08/2023] Open
Abstract
We investigate dissociative electron attachment to tirapazamine through a crossed electron-molecule beam experiment and quantum chemical calculations. After the electron is attached and the resulting anion reaches the first excited state, D1, we suggest a fast transition into the ground electronic state through a conical intersection with a distorted triazine ring that almost coincides with the minimum in the D1 state. Through analysis of all observed dissociative pathways producing heavier ions (90-161 u), we consider the predissociation of an OH radical with possible roaming mechanism to be the common first step. This destabilizes the triazine ring and leads to dissociation of highly stable nitrogen-containing species. The benzene ring is not altered during the process. Dissociation of small anionic fragments (NO2-, CN2-, CN-, NH2-, O-) cannot be conclusively linked to the OH predissociation mechanism; however, they again do not require dissociation of the benzene ring.
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Affiliation(s)
- Eugene Arthur-Baidoo
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria; (E.A.-B.); (J.A.)
- Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria
| | - Joao Ameixa
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria; (E.A.-B.); (J.A.)
- Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria
- Atomic and Molecular Collisions Laboratory, Department of Physics, CEFITEC, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - Milan Ončák
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria; (E.A.-B.); (J.A.)
- Correspondence: (M.O.); (S.D.)
| | - Stephan Denifl
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria; (E.A.-B.); (J.A.)
- Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria
- Correspondence: (M.O.); (S.D.)
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22
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Arthur-Baidoo E, Falkiewicz K, Chomicz-Mańka L, Czaja A, Demkowicz S, Biernacki K, Kozak W, Rak J, Denifl S. Electron-Induced Decomposition of Uracil-5-yl O-( N, N-dimethylsulfamate): Role of Methylation in Molecular Stability. Int J Mol Sci 2021; 22:2344. [PMID: 33652878 PMCID: PMC7956691 DOI: 10.3390/ijms22052344] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/18/2021] [Accepted: 02/21/2021] [Indexed: 01/29/2023] Open
Abstract
The incorporation of modified uracil derivatives into DNA leads to the formation of radical species that induce DNA damage. Molecules of this class have been suggested as radiosensitizers and are still under investigation. In this study, we present the results of dissociative electron attachment to uracil-5-yl O-(N,N-dimethylsulfamate) in the gas phase. We observed the formation of 10 fragment anions in the studied range of electron energies from 0-12 eV. Most of the anions were predominantly formed at the electron energy of about 0 eV. The fragmentation paths were analogous to those observed in uracil-5-yl O-sulfamate, i.e., the methylation did not affect certain bond cleavages (O-C, S-O and S-N), although relative intensities differed. The experimental results are supported by quantum chemical calculations performed at the M06-2X/aug-cc-pVTZ level of theory. Furthermore, a resonance stabilization method was used to theoretically predict the resonance positions of the fragment anions O- and CH3-.
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Affiliation(s)
- Eugene Arthur-Baidoo
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria;
- Center for Biomolecular Sciences Innsbruck, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria
| | - Karina Falkiewicz
- Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland; (K.F.); (L.C.-M.); (A.C.); (W.K.)
| | - Lidia Chomicz-Mańka
- Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland; (K.F.); (L.C.-M.); (A.C.); (W.K.)
| | - Anna Czaja
- Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland; (K.F.); (L.C.-M.); (A.C.); (W.K.)
| | - Sebastian Demkowicz
- Department of Organic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland; (S.D.); (K.B.)
| | - Karol Biernacki
- Department of Organic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland; (S.D.); (K.B.)
| | - Witold Kozak
- Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland; (K.F.); (L.C.-M.); (A.C.); (W.K.)
| | - Janusz Rak
- Department of Physical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland; (K.F.); (L.C.-M.); (A.C.); (W.K.)
| | - Stephan Denifl
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria;
- Center for Biomolecular Sciences Innsbruck, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria
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23
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Meißner R, Feketeová L, Bayer A, Limão-Vieira P, Denifl S. Formation of negative and positive ions in the radiosensitizer nimorazole upon low-energy electron collisions. J Chem Phys 2021; 154:074306. [PMID: 33607883 DOI: 10.1063/5.0040045] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A comprehensive investigation of low-energy electron attachment and electron ionization of the nimorazole radiosensitizer used in cancer radiation therapy is reported by means of a gas-phase crossed beam experiment in an electron energy range from 0 eV to 70 eV. Regarding negative ion formation, we discuss the formation of fifteen fragment anions in the electron energy range of 0 eV-10 eV, where the most intense signal is assigned to the nitrogen dioxide anion NO2 -. The other fragment anions have been assigned to form predominantly from a common temporary negative ion state close to 3 eV of the nitroimidazole moiety, while the morpholine moiety seems to act only as a spectator in the dissociative electron attachment event to nimorazole. Quantum chemical calculations have been performed to help interpreting the experimental data with thermochemical thresholds, electron affinities, and geometries of some of the neutral molecules. As far as positive ion formation is concerned, the mass spectrum at the electron energy of 70 eV shows a weakly abundant parent ion and C5H10NO+ as the most abundant fragment cation. We report appearance energy (AE) measurements for six cations. For the intact nimorazole molecular cation, the AE of 8.16 ± 0.05 eV was obtained, which is near the presently calculated adiabatic ionization energy.
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Affiliation(s)
- R Meißner
- Institute for Ion Physics and Applied Physics and Center for Biomolecular Sciences (CMBI), University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - L Feketeová
- Institute for Ion Physics and Applied Physics and Center for Biomolecular Sciences (CMBI), University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - A Bayer
- Institute for Ion Physics and Applied Physics and Center for Biomolecular Sciences (CMBI), University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - P Limão-Vieira
- Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - S Denifl
- Institute for Ion Physics and Applied Physics and Center for Biomolecular Sciences (CMBI), University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
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24
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Uleanya KO, Dessent CEH. Investigating the mapping of chromophore excitations onto the electron detachment spectrum: photodissociation spectroscopy of iodide ion-thiouracil clusters. Phys Chem Chem Phys 2021; 23:1021-1030. [PMID: 33428696 DOI: 10.1039/d0cp05920j] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Laser photodissociation spectroscopy (3.1-5.7 eV) has been applied to iodide complexes of the non-native nucleobases, 2-thiouracil (2-TU), 4-thiouracil (4-TU) and 2,4-thiouracil (2,4-TU), to probe the excited states and intracluster electron transfer as a function of sulphur atom substitution. Photodepletion is strong for all clusters (I-·2-TU, I-·4-TU and I-·2,4-TU) and is dominated by electron detachment processes. For I-·4-TU and I-·2,4-TU, photodecay is accompanied by formation of the respective molecular anions, 4-TU- and 2,4-TU-, behaviour that is not found for other nucleobases. Notably, the I-·2TU complex does not fragment with formation of its molecular anion. We attribute the novel formation of 4-TU- and 2,4-TU- to the fact that these valence anions are significantly more stable than 2-TU-. We observe further similar behaviour for I-·4-TU and I-·2,4-TU relating to the general profile of their photodepletion spectra, since both strongly resemble the intrinsic absorption spectra of the respective uncomplexed thiouracil molecule. This indicates that the nucleobase chromophore excitations are determining the clusters' spectral profile. In contrast, the I-·2-TU photodepletion spectrum is dominated by the electron detachment profile, with the near-threshold dipole-bound excited state being the only distinct spectral feature. We discuss these observations in the context of differences in the dipole moments of the thionucleobases, and their impact on the coupling of nucleobase-centred transitions onto the electron detachment spectrum.
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Affiliation(s)
- Kelechi O Uleanya
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
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25
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Spisz P, Zdrowowicz M, Kozak W, Chomicz-Mańka L, Falkiewicz K, Makurat S, Sikorski A, Wyrzykowski D, Rak J, Arthur-Baidoo E, Ziegler P, Rodrigues Costa MS, Denifl S. Uracil-5-yl O-Sulfamate: An Illusive Radiosensitizer. Pitfalls in Modeling the Radiosensitizing Derivatives of Nucleobases. J Phys Chem B 2020; 124:5600-5613. [PMID: 32539395 PMCID: PMC7356320 DOI: 10.1021/acs.jpcb.0c03844] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/12/2020] [Indexed: 12/16/2022]
Abstract
Efficient radiotherapy requires the concomitant use of ionizing radiation (IR) and a radiosensitizer. In the present work uracil-5-yl O-sulfamate (SU) is tested against its radiosensitizing potential. The compound possesses appropriate dissociative electron attachment (DEA) characteristics calculated at the M06-2X/6-31++G(d,p) level. Crossed electron-molecular beam experiments in the gas phase demonstrate that SU undergoes efficient DEA processes, and the single C-O or S-O bond dissociations account for the majority of fragments induced by electron attachment. Most DEAs proceed already for electrons with kinetic energies of ∼0 eV, which is supported by the exothermic thresholds calculated at the M06-2X/aug-cc-pVTZ level. However, in water solution under reductive conditions and physiological pH, SU does not undergo radiolysis, which demonstrates the crucial influence of aqueous environment on the radiosensitizing properties of modified nucleosides.
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Affiliation(s)
- Paulina Spisz
- Group
of Biological Sensitizers, Physical Chemistry Department, Faculty
of Chemistry, University of Gdańsk, 80-308 Gdańsk, Poland
| | - Magdalena Zdrowowicz
- Group
of Biological Sensitizers, Physical Chemistry Department, Faculty
of Chemistry, University of Gdańsk, 80-308 Gdańsk, Poland
| | - Witold Kozak
- Group
of Biological Sensitizers, Physical Chemistry Department, Faculty
of Chemistry, University of Gdańsk, 80-308 Gdańsk, Poland
| | - Lidia Chomicz-Mańka
- Group
of Biological Sensitizers, Physical Chemistry Department, Faculty
of Chemistry, University of Gdańsk, 80-308 Gdańsk, Poland
| | - Karina Falkiewicz
- Group
of Biological Sensitizers, Physical Chemistry Department, Faculty
of Chemistry, University of Gdańsk, 80-308 Gdańsk, Poland
| | - Samanta Makurat
- Group
of Biological Sensitizers, Physical Chemistry Department, Faculty
of Chemistry, University of Gdańsk, 80-308 Gdańsk, Poland
| | - Artur Sikorski
- Group
of Crystallochemistry, Physical Chemistry Department, Faculty of Chemistry, University of Gdańsk, 80-308 Gdańsk, Poland
| | - Dariusz Wyrzykowski
- Group
of Physicochemistry and Complex Compounds, General and Inorganic Chemistry
Department, Faculty of Chemistry, University
of Gdańsk, 80-308 Gdańsk, Poland
| | - Janusz Rak
- Group
of Biological Sensitizers, Physical Chemistry Department, Faculty
of Chemistry, University of Gdańsk, 80-308 Gdańsk, Poland
| | - Eugene Arthur-Baidoo
- Institut
für Ionenphysik und Angewandte Physik and Center for Biomolecular
Sciences Innsbruck, Leopold-Franzens Universität
Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Patrick Ziegler
- Institut
für Ionenphysik und Angewandte Physik and Center for Biomolecular
Sciences Innsbruck, Leopold-Franzens Universität
Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Mateus Salomao Rodrigues Costa
- Institut
für Ionenphysik und Angewandte Physik and Center for Biomolecular
Sciences Innsbruck, Leopold-Franzens Universität
Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Stephan Denifl
- Institut
für Ionenphysik und Angewandte Physik and Center for Biomolecular
Sciences Innsbruck, Leopold-Franzens Universität
Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
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26
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Ameixa J, Arthur-Baidoo E, Pereira-da-Silva J, Ryszka M, Carmichael I, Cornetta LM, do N Varella MT, Ferreira da Silva F, Ptasińska S, Denifl S. Formation of resonances and anionic fragments upon electron attachment to benzaldehyde. Phys Chem Chem Phys 2020; 22:8171-8181. [PMID: 32249870 DOI: 10.1039/d0cp00029a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Benzaldehyde is a simple aromatic aldehyde and has a wide range of applications in the food, pharmaceutical, and chemical industries. The positive electron affinity of this compound suggests that low-energy electrons can be easily trapped by neutral benzaldehyde. In the present study, we investigated the formation of negative ions following electron attachment to benzaldehyde in the gas-phase. Calculations on elastic electron scattering from benzaldehyde indicate a π* valence bound state of the anion at -0.48 eV and three π* shape resonances (0.78, 2.48 and 5.51 eV). The excited state spectrum of the neutral benzaldehyde is also reported to complement our findings. Using mass spectrometry, we observed the formation of the intact anionic benzaldehyde at ∼0 eV. We ascribe the detection of the benzaldehyde anion to stabilization of the π* valence bound state upon dissociative electron attachment to a benzaldehyde dimer. In addition, we report the cross sections for nine fragment anions formed through electron attachment to benzaldehyde. Investigations carried out with partially deuterated benzaldehyde show that the hydrogen loss is site-selective with respect to the incident electron energy. In addition, we propose several dissociation pathways, backed up by quantum chemical calculations on their thermodynamic thresholds. The threshold calculations also support that the resonances formed at higher energies lead to fragment anions observable by mass spectrometry, whereas the resonances at low electron energies decay only by electron autodetachment.
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Affiliation(s)
- J Ameixa
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences (CMBI), Leopold-Franzens Universität Innsbruck, Technikerstraße 25/3, 6020 Innsbruck, Austria. and Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
| | - E Arthur-Baidoo
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences (CMBI), Leopold-Franzens Universität Innsbruck, Technikerstraße 25/3, 6020 Innsbruck, Austria.
| | - J Pereira-da-Silva
- Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
| | - M Ryszka
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - I Carmichael
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - L M Cornetta
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, Brazil
| | - M T do N Varella
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, Brazil
| | - F Ferreira da Silva
- Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
| | - S Ptasińska
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, USA and Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - S Denifl
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences (CMBI), Leopold-Franzens Universität Innsbruck, Technikerstraße 25/3, 6020 Innsbruck, Austria.
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27
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Cercola R, Uleanya KO, Dessent CEH. Electron detachment dynamics of the iodide-guanine cluster: does ionization occur from the iodide or from guanine? Mol Phys 2019. [DOI: 10.1080/00268976.2019.1679402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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28
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Spisz P, Zdrowowicz M, Makurat S, Kozak W, Skotnicki K, Bobrowski K, Rak J. Why Does the Type of Halogen Atom Matter for the Radiosensitizing Properties of 5-Halogen Substituted 4-Thio-2'-Deoxyuridines? Molecules 2019; 24:E2819. [PMID: 31382376 PMCID: PMC6695862 DOI: 10.3390/molecules24152819] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 07/30/2019] [Accepted: 07/31/2019] [Indexed: 01/06/2023] Open
Abstract
Radiosensitizing properties of substituted uridines are of great importance for radiotherapy. Very recently, we confirmed 5-iodo-4-thio-2'-deoxyuridine (ISdU) as an efficient agent, increasing the extent of tumor cell killing with ionizing radiation. To our surprise, a similar derivative of 4-thio-2'-deoxyuridine, 5-bromo-4-thio-2'-deoxyuridine (BrSdU), does not show radiosensitizing properties at all. In order to explain this remarkable difference, we carried out a radiolytic (stationary and pulse) and quantum chemical studies, which allowed the pathways to all radioproducts to be rationalized. In contrast to ISdU solutions, where radiolysis leads to 4-thio-2'-deoxyuridine and its dimer, no dissociative electron attachment (DEA) products were observed for BrSdU. This observation seems to explain the lack of radiosensitizing properties of BrSdU since the efficient formation of the uridine-5-yl radical, induced by electron attachment to the modified nucleoside, is suggested to be an indispensable attribute of radiosensitizing uridines. A larger activation barrier for DEA in BrSdU, as compared to ISdU, is probably responsible for the closure of DEA channel in the former system. Indeed, besides DEA, the XSdU anions may undergo competitive protonation, which makes the release of X- kinetically forbidden.
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Affiliation(s)
- Paulina Spisz
- Laboratory of Biological Sensitizers, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Magdalena Zdrowowicz
- Laboratory of Biological Sensitizers, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Samanta Makurat
- Laboratory of Biological Sensitizers, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Witold Kozak
- Laboratory of Biological Sensitizers, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Konrad Skotnicki
- Centre of Radiation Research and Technology, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland
| | - Krzysztof Bobrowski
- Centre of Radiation Research and Technology, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland
| | - Janusz Rak
- Laboratory of Biological Sensitizers, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
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29
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Reactions in the Radiosensitizer Misonidazole Induced by Low-Energy (0-10 eV) Electrons. Int J Mol Sci 2019; 20:ijms20143496. [PMID: 31315268 PMCID: PMC6678818 DOI: 10.3390/ijms20143496] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/11/2019] [Accepted: 07/11/2019] [Indexed: 11/17/2022] Open
Abstract
Misonidazole (MISO) was considered as radiosensitizer for the treatment of hypoxic tumors. A prerequisite for entering a hypoxic cell is reduction of the drug, which may occur in the early physical-chemical stage of radiation damage. Here we study electron attachment to MISO and find that it very effectively captures low energy electrons to form the non-decomposed molecular anion. This associative attachment (AA) process is exclusively operative within a very narrow resonance right at threshold (zero electron energy). In addition, a variety of negatively charged fragments are observed in the electron energy range 0-10 eV arising from dissociative electron attachment (DEA) processes. The observed DEA reactions include single bond cleavages (formation of NO2-), multiple bond cleavages (excision of CN-) as well as complex reactions associated with rearrangement in the transitory anion and formation of new molecules (loss of a neutral H2O unit). While any of these AA and DEA processes represent a reduction of the MISO molecule, the radicals formed in the course of the DEA reactions may play an important role in the action of MISO as radiosensitizer inside the hypoxic cell. The present results may thus reveal details of the molecular description of the action of MISO in hypoxic cells.
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30
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Meißner R, Makurat S, Kozak W, Limão-Vieira P, Rak J, Denifl S. Electron-Induced Dissociation of the Potential Radiosensitizer 5-Selenocyanato-2'-deoxyuridine. J Phys Chem B 2019; 123:1274-1282. [PMID: 30657689 DOI: 10.1021/acs.jpcb.8b11523] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
5-Selenocyanato-2'-deoxyuridine (SeCNdU) is a recently proposed radiosensitizer based on 2'-deoxyuridine (dU) with the electron-affinic selenocyanato (-SeCN) side group attached at the C5 position of uracil. Since electron interaction processes may be an important source of DNA damage by ionizing radiation, we have studied low-energy dissociative electron attachment to SeCNdU in the gas phase. Negative ion formation has been obtained by means of mass spectrometry, where a rich fragmentation pattern is observed even at ∼0 eV. The reaction pathways exhibiting the highest ion yields are C4N2O2H2Se•- and CN-, both involving a cleavage of the Se-CN bond. The heaviest fragment anion observed is C9N2O5H10Se•-, where besides the charged species, the hydrogen and cyano radicals are also formed. Further decomposition channels also yield the highly reactive hydroxyl radical, which possesses a high DNA damage potential. All observed channels have experimentally determined onsets at 0 eV, which are supported by calculations performed at the M06-2X/aug-cc-pVTZ level. The calculations comprise the thermochemical thresholds at standard and experimental (428.15 K, 3 × 10-11 atm) conditions together with the adiabatic electron affinities. The present study shows that low-energy electrons very effectively decompose SeCNdU upon attachment of thermal electrons, producing a large variety of charged fragments and radicals.
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Affiliation(s)
- Rebecca Meißner
- Institut für Ionenphysik und Angewandte Physik and Center for Biomolecular Sciences Innsbruck , Leopold-Franzens Universität Innsbruck , Technikerstrasse 25 , A-6020 Innsbruck , Austria.,Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics , Universidade NOVA de Lisboa , 2829-516 Caparica , Portugal
| | - Samanta Makurat
- Laboratory of Biological Sensitizers, Physical Chemistry Department, Faculty of Chemistry , University of Gdańsk , 80-308 Gdańsk , Poland
| | - Witold Kozak
- Laboratory of Biological Sensitizers, Physical Chemistry Department, Faculty of Chemistry , University of Gdańsk , 80-308 Gdańsk , Poland
| | - Paulo Limão-Vieira
- Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics , Universidade NOVA de Lisboa , 2829-516 Caparica , Portugal
| | - Janusz Rak
- Laboratory of Biological Sensitizers, Physical Chemistry Department, Faculty of Chemistry , University of Gdańsk , 80-308 Gdańsk , Poland
| | - Stephan Denifl
- Institut für Ionenphysik und Angewandte Physik and Center for Biomolecular Sciences Innsbruck , Leopold-Franzens Universität Innsbruck , Technikerstrasse 25 , A-6020 Innsbruck , Austria
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