Role of Humidity and Oxygen Level on Damage to DNA Induced by Soft X-rays and Low-Energy Electrons

Alizadeh, Elahe; Sanche, Léon

doi:10.1021/jp403350j

Cited by 32 publications

(19 citation statements)

References 67 publications

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“…LEEs with an average energy of 5.8 eV and a distribution peaking at 1.4 eV could induce DSBs with G values (i.e., yields per energy deposited in DNA) of 8 to 22 nmol/J, which is 1.6 times larger than that of 1.5-keV photons. Applying a similar and improved technique to produce LEEs, Alizadeh et al measured conformational damages from dry, oxygenated, and humid films of DNA, LEE-irradiated under standard atmospheric temperature and pressure (SATP) [99]. Their results were compared with the yields produced by 1.5-keV X-rays.…”

Section: Clustered Dna Damages Induced By Leesmentioning

confidence: 99%

Clustered DNA Damages induced by 0.5 to 30 eV Electrons

Zheng

Sanche

2019

IJMS

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Low-energy electrons (LEEs) of energies ≤30 eV are generated in large quantities by ionizing radiation. These electrons can damage DNA; particularly, they can induce the more detrimental clustered lesions in cells. This type of lesions, which are responsible for a large portion of the genotoxic stress generated by ionizing radiation, is described in the Introduction. The reactions initiated by the collisions of 0.5–30 eV electrons with oligonucleotides, duplex DNA, and DNA bound to chemotherapeutic platinum drugs are explained and reviewed in the subsequent sections. The experimental methods of LEE irradiation and DNA damage analysis are described with an emphasis on the detection of cluster lesions, which are considerably enhanced in DNA–Pt–drug complexes. Based on the energy dependence of damage yields and cross-sections, a mechanism responsible for the clustered lesions can be attributed to the capture of a single electron by the electron affinity of an excited state of a base, leading to the formation of transient anions at 6 and 10 eV. The initial capture is followed by electronic excitation of the base and dissociative attachment—at other DNA sites—of the electron reemitted from the temporary base anion. The mechanism is expected to be universal in the cellular environment and plays an important role in the formation of clustered lesions.

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Section: Clustered Dna Damages Induced By Leesmentioning

confidence: 99%

Clustered DNA Damages induced by 0.5 to 30 eV Electrons

Zheng

Sanche

2019

IJMS

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“…Alizadeh and Sanche [146] employed this technique to examine how the presence of several cellular components (such as, O 2 , H 2 O and O 2 /H 2 O) modulates the LEE-induced damage to DNA molecules. They observed that for hydrated DNA films in an oxygenated environment, the additional LEE-induced damage that results from the combination of water and oxygen exhibits a super-additive effect, which produces a yield of DSB almost seven times higher than that obtained by X-ray photons.…”

Section: Lees Interaction and Induced Damage Under Cellular Conditionsmentioning

confidence: 99%

Transient Anions in Radiobiology and Radiotherapy: From Gaseous Biomolecules to Condensed Organic and Biomolecular Solids

Alizadeh¹,

Ptasińska²,

Sanche³

2016

Radiation Effects in Materials

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This chapter focuses on the fundamental processes that govern interactions of lowenergy (1-30 eV) electrons with biological systems. These interactions have been investigated in the gas phase and within complex arrangements in the condensed phase. They often lead to the formation of transient molecular anions (TMAs), and their decay by autoionization or dissociation accompanied by bond dissociation. The damage caused to biomolecules via TMAs is emphasized in all sections. Such damage, which depends on a large number of factors, including electron energy, molecular environment, and type of biomolecule, and its physical and chemical interactions with radiosensitizing agents are extensively discussed. A majority of recent findings resulting from experimental and theoretical endeavors are presented. They encompass broad research areas to elucidate important roles of TMAs in irradiated biological systems, from the molecular level to nanoscale cellular dimensions. Fundamental aspects of TMA formation are stressed in this chapter, but many practical applications in a variety of radiation-related fields such as radiobiology and radiotherapy are addressed.

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“…32 Table II presents dry DNA, this ratio is 2.5, which corresponds to tightly bound water molecules attached to the phosphate group that cannot be removed by vacuum desiccation. 49,50 Assuming a nucleosome as a cylinder with diameter and height of 10 and 6 nm, respectively, the absorbed dose in the nucleosome is 2.6 kGy, which is 2 orders of magnitude smaller than that in the DNA, owing to the smaller mass of DNA relative to that of nucleosome. However, the dose of 2.6 kGy is still much higher, by 2 or 3 orders of magnitude, than those currently administered in the clinic for macroscopic volumes.…”

Section: A Absorbed Dose In Dna By Auger Electrons Of 5-18 Evmentioning

confidence: 99%

Correlation between energy deposition and molecular damage from Auger electrons: A case study of ultra-low energy (5-18 eV) electron interactions with DNA

2014

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Purpose-The present study introduces a new method to establish a direct correlation between biologically related physical parameters (i.e., stopping and damaging cross sections, respectively) for an Auger-electron emitting radionuclide decaying within a target molecule (e.g., DNA), so as to evaluate the efficacy of the radionuclide at the molecular level. These parameters can be applied to the dosimetry of Auger electrons and the quantification of their biological effects, which are the main criteria to assess the therapeutic efficacy of Auger-electron emitting radionuclides.Methods-Absorbed dose and stopping cross section for the Auger electrons of 5-18 eV emitted by 125 I within DNA were determined by developing a nanodosimetric model. The molecular damages induced by these Auger electrons were investigated by measuring damaging cross section, including that for the formation of DNA single-and double-strand breaks. Nanoscale films of pure plasmid DNA were prepared via the freeze-drying technique and subsequently irradiated with low-energy electrons at various fluences. The damaging cross sections were determined by employing a molecular survival model to the measured exposure-response curves for induction of DNA strand breaks.Results-For a single decay of 125 I within DNA, the Auger electrons of 5-18 eV deposit the energies of 12.1 and 9.1 eV within a 4.2-nm 3 volume of a hydrated or dry DNA, which results in the absorbed doses of 270 and 210 kGy, respectively. DNA bases have a major contribution to the deposited energies. Ten-electronvolt and high linear energy transfer 100-eV electrons have a similar cross section for the formation of DNA double-strand break, while 100-eV electrons are twice as efficient as 10 eV in the induction of single-strand break.Conclusions-Ultra-low-energy electrons (<18 eV) substantially contribute to the absorbed dose and to the molecular damage from Auger-electron emitting radionuclides; hence, they should be considered in the dosimetry calculation of such radionuclides. Moreover, absorbed dose is not an appropriate physical parameter for nanodosimetry. Instead, stopping cross section, which describes the probability of energy deposition in a target molecule can be an appropriate nanodosimetric parameter. The stopping cross section is correlated with a damaging cross section a)Author to whom correspondence should be addressed. CIHR Author ManuscriptCIHR Author Manuscript CIHR Author Manuscript (e.g., cross section for the double-strand break formation) to quantify the number of each specific lesion in a target molecule for each nuclear decay of a single Auger-electron emitting radionuclide.

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Role of Humidity and Oxygen Level on Damage to DNA Induced by Soft X-rays and Low-Energy Electrons

Cited by 32 publications

References 67 publications

Clustered DNA Damages induced by 0.5 to 30 eV Electrons

Clustered DNA Damages induced by 0.5 to 30 eV Electrons

Transient Anions in Radiobiology and Radiotherapy: From Gaseous Biomolecules to Condensed Organic and Biomolecular Solids

Correlation between energy deposition and molecular damage from Auger electrons: A case study of ultra-low energy (5-18 eV) electron interactions with DNA

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