The DNA damage response in myogenic C2C7 cells depends on the characteristics of ionizing particles

DNA integrity and stability are vital for proper cellular activity. Nevertheless, to treat cancer patients, DNA is the main target for inducing tumoral cell death. Nowadays, cancer treatment is improving by the development of new technologies, protocols and strategies. Amongst them, the charged particle radiotherapies are becoming prevalent. However, tumor-neighboring healthy tissues are still exposed to ionizing radiation (IR) and subject to late side effects. Skeletal muscle is one of those tissues most likely to be affected. To decipher the DNA damage response (DDR) of skeletal muscle cells, myogenic cells, we irradiated them with microbeams of protons or α-particles and followed the accumulation of DDR proteins at localized irradiation sites. Thereby, we showed that myoblasts, proliferating myogenic cells, repair local IR-induced DNA damage through both non-homologous end-joining and homologous recombination with different recruitment dynamics depending on the characteristics of ionizing particles (type, energy deposition and time after irradiation), whereas myotubes, post-mitotic myogenic cells, display globally reduced DNA damage response.