Enhancement of 5-fluorouracil cytotoxicity by folinic acid in different cell-lines of human renal cell carcinoma.

Results of cytotoxic chemotherapy in metastatic renal cell carcinoma are not impressive. Remission rates range between 0 and 20%. One of the substances which show a marginal effect is 5-fluorouracil (5-FU). The cytotoxicity of 5-FU can be modulated by combination with folinic acid as shown in various cell lines and clinical trials. We were interested to see whether such a biomodulation also occurs in renal cell cancer. The antiproliferative effect of 5-fluorouracil on two human cell lines of RCC and its potentiation by folinic acid was investigated in a monolayer proliferation assay. It could be shown that folinic acid enhanced the cytotoxic potential of 5-FU 6-8-fold. Our results indicate that the combination of these two drugs in the treatment of metastatic renal cell cancer might lead to better response rates.