IC50: 7 μM: inhibits parasite growth.

Azaserine, as a naturally occurring serine derivative diazo compound, functions as a purine antagonist and structural analogue of glutamine that inhibits enzymatic activities involving in the pathways of glutamine metabolism. Azaserine, an antibiotic and antitumor agent, is used as a potential antineoplastic agent in clinical studies. Azaserine dampens the biosynthesis of purine via reacting with cysteine residues in the enzyme active sites. In addition, azaserine triggers DNA damage by the formation of carboxymethylated bases and O6-methylguanine.

In vitro: Azaserine showed cytotoxicity in Raji cells, which was partly due to inhibition of de novo purine biosynthesis, and the expression of O6-methylguanine-DNA methyltransferase did not provide protection against cell killing, suggesting that O6-methylguanine was not a major contributor to the cytotoxic DNA damage triggered by azaserine. Azaserine killed the Raji hypoxanthine-guanine phosphoribosyltransferas-deficient(HPRT-) Mex- cells. In contrast, the Raji HPRT+ Mex- cells were more resistant to azaserine. Additionally, azaserine blocked the growth of Raji HPRT+ Mex-cells when treated with 300 μM [1].

In vivo: CD-l mice and W/LEW rats were injected intraperitoneally with azaserine at a dose of 10 mg/kg body weight once a week for 5 weeks. After 6 months, compared to the control rats and mice, the azaserine-treated animals had a slightly higher incidence of pancreatic atypical acinar cell nodules (AACN) and the average size of AACN of azaserine-treated animals was larger. In addition, the concentration of [14C] azaserine and/or its metabolites was lower in mouse pancreas than in rat pancreas [2].

References:
[1].  O'Driscoll, M., Macpherson, P., Xu, Y., & Karran, P. The cytotoxicity of DNA carboxymethylation and methylation by the model carboxymethylating agent azaserine in human cells. Carcinogenesis. 1999; 20(9): 1855-1862.
[2].  B. D. Roebuck, Herman S. Lilja, Thomas J. Curphey, Daniel S. Longnecker; Pathologic and Biochemical Effects of Azaserine in Inbred Wistar/Lewis Rats and Noninbred CD-1 Mice. J Natl Cancer Inst. 1980; 65 (2): 383-389.