Biochemical and Genetic Tests for Inhibitors ofLeishmaniaPteridine Pathways

Hardy, Larry W.; Matthews, W. Stephen; Nare, Bakela; Beverley, S.M.

doi:10.1006/expr.1997.4207

Cited by 101 publications

(96 citation statements)

References 27 publications

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“…The EC 50 value is the concentration of drug required to decrease growth by 50%. Methotrexate and O/129 (2,4-diamino-6,7-diisopropylpteridine) were purchased from Sigma; CB3717 (2-[(4-{[(2,4-diaminoquinazolin-6-yl)methyl](prop-2-yn-1-yl)amino}phenyl)formamido]-pentanedioic acid (26)) was a gift of Ann Jackman, Institute of Cancer Research, Surrey, UK; the folate analogues compound 34 (2,4-diamino-6-(3,4-dichlorophenoxy)-quinazoline) and compound 70 (2,4-diamino-6-benzyl-5-(3-phenylpropyl)-pyrimidine) were as described (11). RPMI low-serine medium for macrophages was prepared the same as the Leishmania RPMI medium, with the addition of 1 mM sodium pyruvate and 10% FIGURE 1.…”

Section: Methodsmentioning

confidence: 99%

“…Leishmania mutants lacking DHFR-TS are thymidine auxotrophs and fail to survive after animal infection (9), providing a genetic validation of this pathway as a potential target for chemotherapy. However, in Leishmania, antifolate therapy is compromised by the presence of pteridine reductase 1, which is less sensitive to classical antifolates and can bypass DHFR inhibition (10,11). Notably, compounds active against both pteridine reductase 1 and DHFR are highly toxic toward Leishmania, and some dual-target compounds also appear to inhibit a third target (11).…”

mentioning

confidence: 99%

“…However, in Leishmania, antifolate therapy is compromised by the presence of pteridine reductase 1, which is less sensitive to classical antifolates and can bypass DHFR inhibition (10,11). Notably, compounds active against both pteridine reductase 1 and DHFR are highly toxic toward Leishmania, and some dual-target compounds also appear to inhibit a third target (11). Together these data suggest that other folate-dependent enzymes including ones participating in thymidylate synthesis may be logical targets for pharmacological intervention.…”

mentioning

confidence: 99%

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The Role of the Mitochondrial Glycine Cleavage Complex in the Metabolism and Virulence of the Protozoan Parasite Leishmania major

Scott

Hickerson

Vickers

et al. 2008

Journal of Biological Chemistry

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For the human pathogen Leishmania major, a key metabolic function is the synthesis of thymidylate, which requires 5,10-methylenetetrahydrofolate (5,10-CH 2 -THF). 5,10-CH 2 -THF can be synthesized from glycine by the mitochondrial glycine cleavage complex (GCC). Bioinformatic analysis revealed the four subunits of the GCC in the L. major genome, and the role of the GCC in parasite metabolism and virulence was assessed through studies of the P subunit (glycine decarboxylase (GCVP)). First, a tagged GCVP protein was expressed and localized to the parasite mitochondrion. Second, a gcvP ؊ mutant was generated and shown to lack significant GCC activity using an indirect in vivo assay after incorporation of label from [2-14 C]glycine into DNA. The gcvP ؊ mutant grew poorly in the presence of excess glycine or minimal serine; these studies also established that L. major promastigotes require serine for optimal growth. Although gcvP ؊ promastigotes and amastigotes showed normal virulence in macrophage infections in vitro, both forms of the parasite showed substantially delayed replication and lesion pathology in infections of both genetically susceptible or resistant mice. These data suggest that, as the physiology of the infection site changes during the course of infection, so do the metabolic constraints on parasite replication. This conclusion has great significance to the interpretation of metabolic requirements for virulence. Last, these studies call attention in trypanosomatid protozoa to the key metabolic intermediate 5,10-CH 2 -THF, situated at the junction of serine, glycine, and thymidylate metabolism. Notably, genome-based predictions suggest the related parasite Trypanosoma brucei is totally dependent on the GCC for 5,10-CH 2 -THF synthesis.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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The Role of the Mitochondrial Glycine Cleavage Complex in the Metabolism and Virulence of the Protozoan Parasite Leishmania major

Scott

Hickerson

Vickers

et al. 2008

Journal of Biological Chemistry

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“…In previous studies, MTX has been shown to be a potent inhibitor of Le. major and T. cruzi DHFR-TS and also to show activity against promastigotes of different Leishmania species (24,26 reported as moderately selective for Le. major and T. cruzi DHFR (25,31).…”

Section: Discussionmentioning

confidence: 96%

“…major and Le. mexicana, as well as T. brucei and T. cruzi (22)(23)(24)(25)(26)(27)(28)(29)(30). It was considered interesting to evaluate the activity of the rDHFR-TS in the presence of classical antifolates.…”

Section: Discussionmentioning

confidence: 99%

Caracterización bioquímica de la enzima bifuncional dihidrofolato reductasa-timidilato sintasa de Leishmania (Viannia) y su evaluación como blanco molecular

et al. 2013

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Antiprotozoal Agents

Friès¹,

Fairlamb²

2003

Burger's Medicinal Chemistry and Drug Discovery

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The chapter provides coverage of all drugs currently used for the treatment of human African trypanosomiasis (African sleeping sickness), American trypanosomiases (Chagas' disease), and leishmaniasis. Collectively, this group of diseases is caused by flagellated protozoan of the order Kinetoplastida. The drugs currently used to treat these diseases include melarsoprol, suramin, pentamidine, organic antimonials, and several nitroheterocyclic agents. The agents have all been in use for 25–75 years. They have a high degree of toxicity and the first four in the preceding list must be given by parenteral injection over a 2‐ to 6‐week time period. Tolerance has developed to most of the drugs in at least some geographical areas. Eflornithine is the only agent approved in the last 50 years for the treatment of African trypanosomiasis, although it is expensive, requires prolonged systemic dosage, and is effective only against T. brucei gambiense . Megazol, trybazine, DB289, and CGP 40215A have all yielded encouraging results in in vivo preclinical studies against African trypanosomiasis. All four of these agents have entered or are scheduled to enter clinical trials. Nifurtimox and benznidazole are the only agents approved to treat Chagas' disease. The agents are toxic, rarely produce long‐term cures, and resistance to them has developed. The third‐generation triazole antifungal agents posaconazole and UR‐9825 have given encouraging preclinical results against Chagas' disease. Meltefosine has been found to be orally active and to produce 98% cure rates of visceral leishmaniasis. New classes of experimental antitrypanosomal agents include the bisphosphonates, which disrupt lipid metabolism, and cysteine protease inhibitors. Agents from both of these mechanistic classes are being advanced as potential antitrypanosomal agents. Kinetoplastid biochemistry offers numerous opportunities for the development of chemotherapeutic agents having a high degree of selective toxicity. Trypanothione, the N 1 , N 8 ‐bis(glutathionyl)spermidine metabolite that replaces glutathione in redox protection reactions in kinetoplastids, is one hopeful target for drug design. A second possible target is the kinetoplastid organelle named the glycosome. African trypanosomes and perhaps other kinetoplastids are highly dependent on glycolysis for energy production. Enclosing the enzymes for glycolysis in glycosomes increases the efficiency of glycolysis compared to its rate in mammalian cells. Any potent inhibitor of an enzyme contained in the glycosome, or of any of the biochemical processes associated with glycosomal function, might be an effective drug against these parasites.

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Biochemical and Genetic Tests for Inhibitors ofLeishmaniaPteridine Pathways

Cited by 101 publications

References 27 publications

The Role of the Mitochondrial Glycine Cleavage Complex in the Metabolism and Virulence of the Protozoan Parasite Leishmania major

The Role of the Mitochondrial Glycine Cleavage Complex in the Metabolism and Virulence of the Protozoan Parasite Leishmania major

Caracterización bioquímica de la enzima bifuncional dihidrofolato reductasa-timidilato sintasa de Leishmania (Viannia) y su evaluación como blanco molecular

Antiprotozoal Agents

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