D. Representative images for TIF quantification: co-localization between 53BP1 (green) and telomeres (red FISH probe), measured 72 h post-transfection with siLuc or siNHP2 in cells further treated with either DMSO or Doxorubicin (DOXO, 1.5 μM) for 2 h. White arrows indicate TIF. Quantification of TIF is shown on the right. A total of at least 100 nuclei were scored from two independent experiments. Each dot represents the number of TIF per nucleus. Statistical analyses were performed using one-way ANOVA with post-hoc Games-Howell's test for multiple comparisons. Data information: All scale bars: 5 μm. Data are shown as mean ± SD, with the red line marking the mean value. 