The Cytotoxic and Radiosensitizing Effects of Taxol in Uterine Sarcoma Cell Lines

Objective : The cytotoxic and radiosensitizing effects of Taxol in uterine sarcoma cell lines were inves tigated. Methods : Two uterine sarcoma cell line with different Taxol responses were used, namely, Taxol sensitive and MDR gene negative MES-SA, and Taxol-resistant and MDR gene positive MES-SA/MX2 cells. These cells were treated with Taxol, radiation, or both, and cytotoxicities were compared by XTT assay and TUNEL staining. The cytotoxic mechnism was also studied by flow cytometry and by RT-PCR of the MDR gene expression. Results : In Taxol-sensitive MES-SA cell lines, Taxol showed highly cytotoxic activity than radiation or the Taxol-radiation combined treatment.On the contrary, in Taxol-resistant MDR positive MES-SA/MX2 cell lines, Taxol significantly increased the sensitivity to radiation therapy, and increased cytotoxicity and apoptosis. Flow cytometry showed that treatment with Taxol alone produced the highest rate of cell cycle shifting to the GO/Gl phase in the MES-SA cell line. However, in the MES-SA/MX2 cell line, Taxol only treatment did not show significant cell cycle shifting compared to the control group. However, in cases of combined Taxolradiation treatment, the rate of cell cycle shifting was higher than for radiation treatment only. Conclusion : Taxol has cytotoxic and radiosensitizing effects on uterine sarcoma cell lines.