FIG. 4.

Expression of the BH3-only proteins, p53 and p21, after exposure to KSP-IA or paclitaxel and the influence of z-VAD on mitotic arrest and mitotic slippage. A2780 cells were treated with KSP-IA (300 nM) or paclitaxel (100 nM) in the presence or absence of z-VAD (200 μM) for 16, 24, or 48 h. Harvested cells were analyzed for cellular DNA content, mitotic index, the expression and phosphorylation of proteins as indicated, and caspase-3 activity (caspase-3-mediated cleavage of PARP [c-PARP]). The percentages of tetraploid cells (4N DNA content) and mitotic index are shown.