Binuclear Dinitrosyl Iron Complexes with Cysteine Inhibit the Development of Experimental Tumor

Abstract

Binuclear dinitrosyl iron complexes with cysteine, which are donors of nitrosonium (NO+) cations, exhibit high antitumor activity when exposed to a formed tumor (Lewis lung carcinoma) with a mass of 0.42 g (12 days after grafting), causing an 11-day inhibition of tumor growth by 90% and an increase in the time of doubling the tumor mass by 9.3 times compared with the control. At the early stage of the administration of the complexes, on the next day after the tumor grafting, their noticeable effect on the tumor growth rate was not observed. It is assumed that the difference in the antitumor effect of dinitrosyl iron complexes with cysteine, depending on the size of the tumor, is due to the different ratio between the level of immunocompetent cells (macrophages) that selectively tolerate these complexes and retain this ability, and the concentration of tumor cells that accept the complexes. Upon late administration of dinitrosyl iron complexes with cysteine, this ratio increases due to a decrease in the number of tumor cells available to immunocompetent cells, it is limited to cells localized only in the peripheral (“surface”) layer of the tumor.