Role of extracellular DNA oxidative modification in radiation induced bystander effects in human endotheliocytes

► We found that extracellular DNA from irradiated cells influences non-irradiated ones. ► ROS and NO production in non-irradiated HUVECs are similar to bystander effect. ► These effects at least partially depend on TLR9 signaling. ► Irradiation-related oxidation of DNA is an important component of bystander effect.