Figure 3.

The sensitivity of M phase progression to taxol in the presence and absence of FTI. MCF-7 cells were seeded at 1 million/10-cm dish and placed the following day in varying concentrations of taxol in the presence of 1 μM FTI or vehicle control (PBS). After 24 h of taxol exposure, cells were harvested and cell cycle distribution was determined as described in Materials and Methods. Increasing the concentration of FTI to 10-μM does not increase the twofold sensitization of M phase progression to taxol seen here (data not shown), indicating that the effect is maximal at 1 μM FTI. In MDA-MB-468 cells, taxol causes an M phase block with a much higher degree of apoptotic cell death and shows a similar FTI-induced sensitization of mitosis to taxol.