Prodrug modification increases potassium tricyclo[188.8.131.52(2,6)]-decan-8-yl dithiocarbonate (D609) chemical stability and cytotoxicity against U937 leukemia cells.
Recombinant human tumor necrosis factor (rh TNF) when administered intravenously together with the phospholipase C inhibitor tricyclodecan-9-yl-xanthogenate (D609) and lauric acid (C12), leads to the partial regression of various human tumor transplants in athymic mice. Extensive necrosis occurred after a single intravenous infusion, with no detectable side effects. TNF-mediated cytotoxicity was found to be correlated with the depletion of energy in HeLa cells. The activity of rh TNF was enhanced by the absence of glucose, while it was reduced by addition of extraneous ATP. In the presence of rh TNF, D609, and C12, cellular energy metabolism was almost completely switched to glycolysis. Under these conditions the cytocidal activity of rh TNF on HeLa cells was amplified at least 60-fold.