Paclitaxel/Taxol® sensitivity in human renal cell carcinoma is not determined by the p53 status

In this study, we analyzed the role of the p53 status for paclitaxel/Taxol® sensitivity in renal cell carcinomas (RCCs) of the clear cell type. Using immunohistochemistry, nuclear p53 accumulation could not be correlated to the paclitaxel/Taxol® sensitivity. DNA sequencing detected a p53 gene mutation in two out of eight RCC cell lines, i.e. in exon 8 (cell line clearCa-6), and in exon 9 (cell line clearCa-5). No correlation, however, was found between the p53 status of our RCC cell lines and their paclitaxel/Taxol® sensitivity as indicated by the IC₅₀ values. However, paclitaxel-induced growth inhibition in paclitaxel-sensitive RCC cell lines was accompanied by an increase in apoptosis, irrespective of their p53 status. Although CD95 up-regulation was observed in renal cell carcinoma with wild-type p53 upon paclitaxel treatment, paclitaxel-induced apoptosis itself is triggered independently from the CD95 system. In conclusion, the p53 status cannot predict paclitaxel/Taxol® sensitivity in RCC cell lines of the clear cell type.