[Effect of paclitaxel on cisplatin resistant head and neck squamous multicellular tumor spheroids]

Paclitaxel has been reported to be effective for the treatment of CDDP resistant tumors. Thus, the efficacy of paclitaxel on CDDP resistant HEp-2 and KB head and neck squamous carcinoma cell lines was evaluated in monolayer and multicellular tumor spheroids (MTS). Cell lines with a tenfold resistance to CDDP were used in this study (Tanaka, K. et al, Keio J Med, 70. 1993). MTS were developed using the liquid overlay culture technique. After exposure to graded concentrations of drugs and different exposure time, the cells were subjected to a clonogenic assay. The effect of paclitaxel on both monolayer and MTS was dependent on the drug concentration and related to the exposure time. For HEp-2 MTS, 10(-7) M/L of paclitaxel resulted in a cell death rate of approximately 90% in both parent and resistant cells. For KB MTS, the cells were more resistant to paclitaxel than the HEp-2 cells, and a 72 hour exposure time was needed to achieve a cell death rate of approximately 90%. These data suggest that paclitaxel may be effective for treating CDDP resistant head and neck cancer.