Comet Assay analysis of DNA strand breaks after exposure to the DNA-incorporated Auger Electron Emitter Iodine-125
| Autor: | Kathrin Holtmann, Ralf Kriehuber, Marcus Unverricht-Yeboah |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Double strand
Radiological and Ultrasound Technology DNA damage fungi genetic processes Auger electron emitter chemistry.chemical_element Iodine 030218 nuclear medicine & medical imaging Ionizing radiation Comet assay enzymes and coenzymes (carbohydrates) 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine chemistry 030220 oncology & carcinogenesis health occupations Biophysics Radiology Nuclear Medicine and imaging biological phenomena cell phenomena and immunity DNA Single strand |
| Zdroj: | International Journal of Radiation Biology. 99:64-69 |
| ISSN: | 1362-3095 0955-3002 |
| Popis: | Ionizing radiation causes various types of DNA damage e.g. single strand breaks (SSB) and double strand breaks (DSB), whereby the SSB/DSB ratio is shifted toward the DSB with increasing LET. For the DNA-incorporated Auger electron emitter Iodine-125 a SSB/DSB ratio of 5.4:1 is calculated based on computer simulations. In the presented work the SSB/DSB ratio of DNA-incorporated Iodine-125 was experimentally determined and compared to external homogenous γ-irradiation.Iodine-125-iododeoxyuridine (I-125-UdR) was incorporated into the DNA of SCL-II cells and cells were subsequently frozen for decay accumulation. Accordingly, external γ-irradiation (Cs-137) experiments were performed in frozen cells. After exposure the neutral or alkaline Comet Assay was performed to quantify DSB or DSB and SSB, respectively. Automated quantification of the comets was performed using the Olive Tail Moment (Metafer CometScan; MetaSystems). Calculation of absorbed dose for Auger electrons on cellular level is extremely biased due to the exclusive DNA localization of I-125-UdR. To avoid dose calculation the γ-H2AX assay was used in order to allow the comparison of the Comet Assay data between both investigated radiation qualities.For low-LET γ-radiation, a SSB/DSB ratio of 10:1 was determined. In contrast, a lower SSB/DSB ratio of 6:1 was induced by DNA-incorporated Iodine-125 which compares very well to the calculated values of Pomplun and co-authors.DNA-incorporated Iodine-125 induces a high-LET type DNA damage pattern in respect to SSB/DSB ratio. |
| Databáze: | OpenAIRE |
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