Figure 1

Different patterns of arrest and slippage in HCT116 and HT29 cell lines. Cells were synchronized by a thymidine block for 18 h. After the block, paclitaxel (100 nM) was added, and cells were collected at the indicated timepoints. (a) Most HCT116 cells escape from mitosis at 24 h after paclitaxel treatment. (b) In contrast, almost 40% of HT29 cells are still in mitosis after 48 h of paclitaxel treatment. The mitotic index was determined by light microscopy, whereas the 4N cell population was defined by the DNA content as determined by flow cytometry.