Synergistic cytotoxic effect of human recombinant tumor necrosis factor alpha combined with dihydroambazone.

Dihydroambazone (DHA) is a water-soluble derivative of the experimental anticancer drug ambazone. In vitro, a combination of DHA and human recombinant tumor necrosis factor alpha (TNF) exerted a strong synergism of cytotoxicity against both mouse melanoma B16K cells and the TNF-sensitive mouse fibroblast line L-M (S). Furthermore, in a colony-forming assay with B16K cells a combination of TNF and DHA inhibited colony-formation much more severely than either drug alone. An increased antiproliferative efficiency was also confirmed in vivo against established subcutaneous melanoma B16 tumors of C57BL/6 mice.