Fig. 3

a Immunofluorescence staining after 6 days treatment of BxPC-3 cells with 120 nM campthotecin. p21 (green) was used as senescence marker, α-tubulin (red) as cytoskeleton marker and dapi (blue) for nuclear staining. Small blue cells are dead cells that were hyperthermized for 45 min at 56 °C. Filled arrowheads represent CIC of dead cells during the process or after engulfing. Open arrowheads represent dead cells engulfed by living, non-senescent cells. Orthogonal sections of one (b) non-senescent and one (c) senescent cell with an engulfed dead cell. Image planes of the X, Y and Z planes are visualized. d p21+ cells with an enclosed dead cell. e The proportion of non-senescent living blue cells (p21-) and senescent living p21+ green cells was analyzed. The dead cells were presented as a percentage of the living cells. f Cells treated with campthotecin and the percentage of dead cells included in p21+ senescent cells and in p21- non-senescent cells. n = number of cells counted in at least three independent experiments. Differences were analyzed by a two-tailed unpaired Mann-Whitney U. Scale bars: 10 μm