Mechanism of Potentiation of the Carcinostatic Activity of 8-Aza-guanine by 4 (or 5)-Aminoimidazole-5 (or 4)-carboxamide Analogs

Abstract

The antitumor activity of 8-AG was potentiated by its administration with AICA or Aza-AICA to Ehrlich ascites carcinoma in mice. AICA or Aza-AICA alone had no carcinostatic actions, but Monomethyl-TICA alone was found to be slightly carcinostatic at the concentration used in these experiments. AICA and Monomethyl-TICA inhibited liver 8-AG deaminase activity of normal mice, but Aza-AICA did not. Neither AICA nor Aza-AICA affected the activity of the liver xanthine oxidase of normal mice. Therefore, the potentiating actions of AICA and Monomethyl-TICA on 8-AG may be to their inhibitory effects on 8-AG deaminase activity. That of Aza-AICA could be due to a different action from those of the former two compounds.