The Role of DNA Damage Induced by Low/High Dose Ionizing Radiation in Cell Carcinogenesis

Cell damage caused by ionizing radiation is very complex, and has generalities and specificities regarding different ionizing radiation types, characters and radiating methods. These specificities have a complicated molecular mechanism and result in various radiobiological responses; however, the details remain unclear. Ionizing radiation can impair biological macromolecules in cells, such as DNA, RNA, signal proteins. Moreover, different radiation doses, as well as linear energy transfer (LET), cause various effects. Cells show a certain adaptive response to low-dose ionizing radiation (LDIR) when they receive a secondary larger dose of radiation. By contrast, high-dose or LET ionizing radiation can lead a much more serious attack on macromolecules, especially to the molecules involved in gene mutations, DNA single strand breaks (SSBs), DNA double strand breaks (DSBs) and DNA damage repair responses. Under extreme conditions, such as space radiation during a space mission, a large amount of abnormally repaired DNA may vastly affect the cell signal transduction pathway, initiate apoptosis, uncontrolled cell proliferation, and even carcinogenesis. In this mini-review, the molecular mechanism of carcinogenesis induced by high-dose and LET ionizing radiation in cell lifespan is elucidated.