FIG. 6.

Loss of p53 sensitizes tumor cells to spindle inhibitors. (a) U2OS Neo and E6 cells were untreated (−) or treated for 24 h with adriamycin (0.2 μg/ml) (A), 0.2 μM etoposide (E), or 1 μM paclitaxel (T). Western blot analysis of lysates was performed for p53 and p21. Ran was used as to confirm that an equivalent amount of protein was loaded in each lane. (b) U2OS Neo and E6 were treated with 1 μM paclitaxel or nocodazole (1 μg/ml). After 48 h cells were harvested and collected for fluorescence-activated cell sorting analysis. Cell death was scored as the percentage of cells with a DNA content of less than 2N. (c) U2OS Neo and E6 cells were plated at 2.4 × 10⁴ cells per well in a 12-well dish and treated with the indicated doses of paclitaxel for 24 h. After 24 h of treatment, the medium was removed and replaced with fresh medium without paclitaxel. Cells were grown for 7 days and then stained with Coomassie blue.