Inhibition of Tumor-induced Angiogenesis by Ribonuclease Inhibitor

The effect of recombinant ribonuclease inhibitor on angiogenesis induced by B16-F10 cells was examined in syngeneic mice. Ribonuclease inhibitor coated with a slow release substance caused a marked decrease of the number of vessels toward tumor mass (angiogenic response), however, injection of ribonuclease in-hibitor did not. Ribonuclease inhibitor did not directly affect the growth of tumor cell or endothelial cell in vitro. These results suggest that ribonuclease inhibitor could be an inhibitor of tumor-induced angiogenesis by using an appro-priate delivery system and stabilizing its activity