Biological effects of ionizing radiation and clustered DNA damage
After living cells are exposed to ionizing radiation, a variety of chemical modifications of DNA are induced either directly by ionization of DNA or indirectly through interactions with water-derived radicals. The DNA lesions include single strand breaks (SSB), base lesions, sugar damage, and apurinic/apyrimidinic sites (AP sites). It has been postulated that a significant amount of clustered DNA damage could be generated by ionizing radiation especially by that of high LET. Clustered DNA damage is defined as two or more lesions within one to two helical turns of DNA induced by a single radiation track. A double strand break (DSB) of DNA is a type of clustered DNA damage, in which single strand breaks are formed on opposite strands in close proximity. Formation and repair of DSBs have been studied in great detail over the years as they have been linked to important biological endpoints, such as cell death, loss of genetic material, and chromosome aberration. We are investigating non-DSB type of clustered DNA damage, as it has received less attention and its significance remained largely unknown. Our studies on the yield of non-DSB clustered damage induced by ion-particle irradiation as well as the biological consequences of non-DSB clustered DNA damage will be presented.
Quantum Beam Science Research Directorate, National Institutes of Quantum and Radiological Science and Technology, Kansai Photon Science Institute, Kizugawa-Shi, Kyoto, Japan
Domain 1 - UMR 3347 / U1021 - Normal and pathological signaling