Taxol sensitizes human ovarian cancer cells to radiation.

Taxol is an exciting antineoplastic agent with a novel mechanism of action. This study was designed to explore the potential use of taxol as a radiation sensitizer. Three human ovarian cancer cell lines were used: BG-1, SKOV-3, and OVCAR-3. These cell lines were treated in the proliferative and confluent state with taxol doses of 0.0001X, 0.0005X, 0.001X, 0.005X, and 0.01X peak plasma concentration of taxol for 90 min and then irradiated either 24 or 48 hr later. Doses of cobalt60 were 0, 2, 5, 8, and 10 Gy. ATP bioluminescence assays were performed on Day 7 after irradiation. Survival data was fit to the linear-quadratic model and mean inactivation dose D was calculated. Data analysis with t test and analysis of variance was performed. Taxol was found to have a significant radiosensitizing effect on all cell lines. Proliferating cells were more sensitive to taxol, radiation, and the combination than confluent cells. Treatment of proliferating cells with taxol 48 hr prior to irradiation had a greater radiosensitizing effect than treatment 24 hr prior to irradiation. In summary, taxol is a potent radiosensitizer in ovarian cancer cell lines and should be considered for further study.