Monte Carlo simulations of cell response to DNA damage of various complexities

DNA is the fundamental molecule encoding and storing the genetic information of all living organisms. DNA damage and repair is by essence a multidisciplinary line of research, and the award of the Nobel Prize of Chemistry in 2015 stresses out the importance of gaining molecular insights into the underlying complex mechanistic pathways. The genetic material is a labile substance that is constantly damaged either spontaneously or due to the action of DNA damaging agents like ionising radiation. Although the damage is efficiently repaired, the DNA repair process is not error free, so that some lesions are misrepaired, leading to genetic modifications called mutations. These lesions can be visualised with the specific repair proteins, which produce the nuclear regions called foci. Ionising radiation itself is a unique DNA damaging agent in that it induces lesions in a strictly controlled manner, both with respect to the duration of damage induction and the transmitted energy (described as the dose and given in Gy, whereby 1 Gy equals to 1 J per kg). The characteristics of the initial physical features of the interaction of ionising radiations with living matter are a major determinant of their final biological consequences. In the presented project focus formation will be simulated in cells exposed to radiations, which differ in the way how hits are distributed inside a nucleus. While X-rays are sparsely ionizing, alpha particles hit cells in a highly condensed manner, as single tracks. A combined exposure places the cell in a particularly difficult situation of experiencing both hit scenarios as it’s shown below.