Genomic DNA ionizing radiation damage sites (DNA damage sites)

Genomic DNA serves as the primary biological target for ionizing radiation (IR) in clinical oncology and environmental health. IR induces a spectrum of damage, most notably single-strand breaks (SSBs), double-strand breaks (DSBs), and base modifications like 8-oxoguanine, occurring through both direct ionization of the phosphodiester backbone and indirect effects mediated by hydroxyl radicals (Desouky et al., 2015, J. Radiat. Res. Appl. Sci.). These damage sites trigger the DNA damage response (DDR), a complex signaling network that coordinates cell cycle arrest and recruitment of repair machinery, such as the non-homologous end joining (NHEJ) or homologous recombination (HR) pathways (Jackson and Bartek, 2009, Nature). In cancer therapy, the deliberate induction of these lesions is the fundamental mechanism of radiotherapy, intended to surpass the repair capacity of malignant cells and drive them toward apoptosis or senescence. However, the persistence of unrepaired or misrepaired DNA damage sites in healthy tissue can lead to genomic instability, contributing to the development of secondary cancers and long-term radiation-induced toxicities (Hall and Giaccia, 2018, Radiobiology for the Radiologist). Pharmacological intervention often targets these sites using radiosensitizers to enhance damage or radioprotectors like Amifostine to scavenge free radicals and shield normal cells (Kouvaris et al., 2007, The Oncologist).

Other names

DNA lesionsRadiation-induced DNA damageDNA double-strand breaksDNA single-strand breaksOxidative DNA damageClustered DNA damage

Induction of DNA strand breaks and oxidative modifications via direct energy deposition or indirect action through reactive oxygen species (ROS) generated by water radiolysis.