Research Paper Volume 4, Issue 11 pp 823—842

Figure 1. Characterization of drug-evoked senescence of HCA2 fibroblasts. (A) HCA2 cultures stained with anti γH2A.X. Blue, DAPI; red, γH2A.X. Each image represents a projection of all optical sections through a cellular culture. Representative images are shown for each condition: Normal proliferating HCA2 cells (−Bleo), same cells under conditions of acute DNA damage (+Bleo, 3 h), and drug-evoked senescence (+Bleo, 5 days). (B) Quantification of γH2A.X-foci frequency upon bleomycin treatments as described earlier. Typical representations of cells with varying numbers of γH2A.X foci per cell are shown in the right column. On an average, more than 200 cells were screened per condition in independent experiments. (C) Staining for the marker of cellular senescence, senescence-associated β-galactosidase. Drug-evoked senescence HCA2 cells (+Bleo, 5 days) exhibited both an increase in senescence-associated β-galactosidase levels and morphological alterations.