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

Binuclear dinitrosyl iron complexes with cysteine (B-DNIC-Cys), which are donors of nitrosonium cations (NO+), exhibit high antitumor activity when exposed to a formed tumor weighing 0.42 grams (12 days after transplantation), causing a 90% inhibition of tumor growth for 11 days and a 9.3-fold increase in the time of tumor mass doubling compared to the control (Lewis lung carcinoma). With early initiation of the complex administration − the next day after tumor transplantation – any noticeable effect on the tumor growth rate was not observed. It is assumed that the detected difference in the antitumor action of dinitrosyl iron complexes with cysteine depending on the tumor size is due to different ratios between the level of immunocompetent cells (macrophages) that selectively transfer these complexes and retain this ability, and the concentration of tumor cells that accept the complexes. With late initiation of the administration of dinitrosyl iron complexes with cysteine, this ratio increases due to a decrease in the number of tumor cells accessible to immunocompetent cells: it is limited to cells localized only in the peripheral (“superficial”) layer of the tumor.

dinitrosyl iron complexes, nitrosonium cations, Lewis lung carcinoma in mice