FIGURE 5.

TOPK confers resistance to doxorubicin-mediated HeLa cancer cell apoptosis. A, HeLa-TOPK siRNA cells or control siRNA cells on cover glass were treated with doxorubicin (Dox, 1 μm) for 24 h. TUNEL assay was employed for apoptosis analysis. The cells were observed by immunofluorescence microscopy. The percentage of dead cells was estimated by calculating dead cells and live cells (300 cells minimum). Representative images of at least three independent experiments are shown. B, TOPK siRNA cells or control siRNA cells were incubated with doxorubicin (1 μm) for 24 h. The levels of cleaved caspase 8, caspase 3, and PARP were indicated. C, TOPK siRNA cells were stimulated with doxorubicin (1 μm) in the presence or absence of each 20 μm of Z-VAD-FMK or Z-IETD-FMK. Cleaved PARP level was shown. D, TOPK siRNA cells were treated with doxorubicin (1 μm) in the presence or absence of 10 μm each SB202190, SP600125, and U0126. The amount of cleaved PARP was indicated. IB, immunoblot; DMSO, dimethyl sulfoxide.