Combined effect of tumor necrosis factor alpha and anticancer chemotherapeutic agents against human renal carcinoma cell lines.

Antitumor effect of recombinant human tumor necrosis factor alpha (TNF) alone or in combination with various anticancer chemotherapeutic agents was tested using an in vitro antiproliferative assay on four human renal carcinoma cell lines (VMRC-RCW, VMRC-RCZ, Caki-1 and A-498). When the dose-dependent effect of TNF was studied, none of the four cell lines showed a 50% or more inhibition even at a concentration of 10,000 U/ml of TNF, so that the susceptibility to TNF was low. An enhancing effect of TNF on the cytotoxic effect of almost all the chemotherapeutic agents tested was observed against VMRC-RCZ and A-498. Against VMRC-RCW and Caki-1, the combination of TNF with the chemotherapeutic agents did not result in an enhancing effect. Mitomycin C showed an enhancing effect of TNF against all four cell lines. These results suggested that the combined treatment of TNF with chemotherapeutic agents may have favorable results in clinical trials.