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Novel Triazine JPC-2067-B Inhibits Toxoplasma gondii In Vitro and In Vivo

Mui, E.J., Schiehser, G.A., Milhous, W.K., Hsu, H., Roberts, C.W., Kirisits, M., Muench, S., Rice, D., Dubey, J.P., Fowble, J.W., Rathod, P.K., Queener, S.F., Liu, S.R., Jacobus, D.P., McLeod, R. and Matlashewski, G. (2008) Novel Triazine JPC-2067-B Inhibits Toxoplasma gondii In Vitro and In Vivo. PLoS Neglected Tropical Diseases, 2 (3). e190. ISSN 1935-2735

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Abstract

BACKGROUND AND METHODOLOGY

Toxoplasma gondii causes substantial morbidity, mortality, and costs for healthcare in the developed and developing world. Current medicines are not well tolerated and cause hypersensitivity reactions. The dihydrotriazine JPC-2067-B (4, 6-diamino-1, 2-dihydro-2, 2-dimethyl-1-(3′(2-chloro-, 4-trifluoromethoxyphenoxy)propyloxy)-1, 3, 5-triazine), which inhibits dihydrofolate reductase (DHFR), is highly effective against Plasmodium falciparum, Plasmodium vivax, and apicomplexans related to T. gondii. JPC-2067-B is the primary metabolite of the orally active biguanide JPC-2056 1-(3′-(2-chloro-4-trifluoromethoxyphenyl​oxy)propyl oxy)- 5-isopropylbiguanide, which is being advanced to clinical trials for malaria. Efficacy of the prodrug JPC-2056 and the active metabolite JPC-2067-B against T. gondii and T. gondii DHFR as well as toxicity toward mammalian cells were tested.

PRINCIPAL FINDINGS AND CONCLUSIONS

Herein, we found that JPC-2067-B is highly effective against T. gondii. We demonstrate that JPC-2067-B inhibits T. gondii growth in culture (IC50 20 nM), inhibits the purified enzyme (IC50 6.5 nM), is more efficacious than pyrimethamine, and is cidal in vitro. JPC-2067-B administered parenterally and the orally administered pro-drug (JPC-2056) are also effective against T. gondii tachyzoites in vivo. A molecular model of T. gondii DHFR-TS complexed with JPC-2067-B was developed. We found that the three main parasite clonal types and isolates from South and Central America, the United States, Canada, China, and Sri Lanka have the same amino acid sequences preserving key binding sites for the triazine.

SIGNIFICANCE

JPC-2056/JPC-2067-B have potential to be more effective and possibly less toxic treatments for toxoplasmosis than currently available medicines.

Item Type: Article
Copyright, Publisher and Additional Information: This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Institution: The University of Sheffield
Academic Units: The University of Sheffield > University of Sheffield Research Centres and Institutes > The Krebs Institute for Biomolecular Research (Sheffield)
Depositing User: Sheffield Import
Date Deposited: 30 Oct 2009 14:14
Last Modified: 08 Feb 2013 16:59
Published Version: http://dx.doi.org/10.1371/journal.pntd.0000190
Status: Published
Publisher: Public Library of Science
Identification Number: doi: 10.1371/journal.pntd.0000190
URI: http://eprints.whiterose.ac.uk/id/eprint/10027

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