Fig. 2

Results related to serial cell passages and γ-ray radiations. a Accumulation of population doubling levels during three passages of A549 cells treated with 5 nmol/L vitamin D or its vehicle. b Accumulation of population doubling levels during three passages of myofibroblasts treated with 5 nmol/L vitamin D or its vehicle. c Kinetics of DNA repair of DSBs induced by γ-radiation (3Gy). A549 cells were treated with 5 nmol/L vitamin D or its vehicle 2 h before irradiations and then subjected to 3Gy of γ-ray. At different times post-irradiation, cells were processed for indirect immunofluorescence of TP53BP1 to detect DSBs. DNA DD foci were quantified from representative micrographs (more than 150 cells examined). Bottom pictures show representative micrographs of the kinetics at 15 min and 28 h post-irradiation