Figure 9. Apoptosis can still be induced when senescence is already established.

A. LS174T cells have been treated with sn38 (5 ng/mL or 12.7 nM) for 96 hrs (lane 2), serum was added (lane 3) in the absence or presence of GSK690693 (20μM, lane 3) or Akti 1/2 (10μM, lane 4) for 3 days in 10% serum. B. In these experimental conditions, total cell extracts were prepared, and p21waf1 expression was then evaluated by western blot (n = 4). C. In the same condition, the percentage of Δ-galactosidase-positive cells was evaluated (n = 4, +/− sd). D. In these experimental conditions, total cell extracts were prepared, and p21waf1 expression was then evaluated by western blot (n = 4).