Figure 3.

Radiation-induced bystander effect (RIBE). Ionizing radiation can directly cause DNA damage and activate the DNA damage response and repair reactions pathway (DDR/R), while the latter activates macrophages through the release of damage-associated molecular pattern molecules (DAMPs), thereby further enhancing the inflammatory and immune response. The reactive oxygen species (ROS)/nitric oxide (NO) and various cytokines produced by the damaged cells eventually crosstalk with the bystander cells through various paths, causing damage to the cells. PGE2: prostaglandin E2; PRR: pattern recognition receptor.