ABSTRACT
The anti-tumor activity of the binuclear form of dinitrosyl iron complexes with glutathione against Lewis lung carcinoma, found earlier upon intraperitoneal administration of the complexes, was also observed when this preparation was injected subcutaneously. A 100 µM/kg subcutaneous dose of the complex being used daily (as calculated per one iron atom in binuclear dinitrosyl iron complexes) for 10 or 15 days, inhibited the tumor growth by 43%. The effect was observed during the first two weeks after tumor transplantation. After that, the tumors began to grow at the rate equal to or even higher than that one for control animals. The mean survival time for treated mice exceeded the control values by 30%. Binuclear dinitrosyl iron complexes administered intraperitoneally was also effective against Ca-755 adenocarcinoma. However, in this case the mean survival time for treated animals increased only by 7%. The anti-tumor activity of S-nitrosoglutathione against Lewis lung carcinoma growth inhibition by 70% and Ca-755 adenocarcinoma growth inhibition by 90% was also shown. However, unlike binuclear dinitrosyl iron complexes the anti-tumor effect of S-nitrosoglutathione decreased when a daily dose of the compound increased (from 200 to 400 µM/kg) The initial anti-tumor effect of binuclear dinitrosyl iron complexes and S-nitrosoglutathione is suggested to be due to NO released from both compounds. A subsequent suppression of the effect is determined by the development of anti-nitrosative and anti-oxidant defense systems in tumors.
