Quantifying DNA damage induced by ionizing radiation and hyperthermia using single DNA molecule imaging.

Quantifying DNA damage induced by ionizing radiation and hyperthermia using single DNA molecule imaging. Transl Oncol. 2020 Jul 08;13(10):100822 Authors: Singh V, Johansson P, Torchinsky D, Lin YL, Öz R, Ebenstein Y, Hammarsten O, Westerlund F Abstract Ionizing radiation (IR) is a common mode of cancer therapy, where DNA damage is the major reason of cell death. Here, we use an assay based on fluorescence imaging of single damaged DNA molecules isolated from radiated lymphocytes, to quantify IR induced DNA damage. The assay uses a cocktail of DNA-repair enzymes that recognizes and excises DNA lesions and then a polymerase and a ligase incorporate fluorescent nucleotides at the damage sites, resulting in a fluorescent "spot" at each site. The individual fluorescent spots can then be counted along single stretched DNA molecules and the global level of DNA damage can be quantified. Our results demonstrate that inclusion of the human apurinic/apyrimidinic endonuclease 1 (APE1) in the enzyme cocktail increases the sensitivity of the assay for detection of IR induced damage significantly. This optimized assay also allowed detection of a cooperative increase in DNA damage when IR was combined with mild hyperthermia, which is sometimes used as an adjuvant in IR therapy. Finally, we discuss how the method may be used to identify patients that are sensitive to IR and other types of DNA damaging agents. PMID: 32652469 [PubMed - as supp...
Source: Translational Oncology - Category: Cancer & Oncology Authors: Tags: Transl Oncol Source Type: research