Discovery and Optimisation of a Compound Series active against Trypanosoma cruzi, the causative agent of Chagas’ Disease

Chagas disease is caused by the protozoan parasite; Trypanosoma cruzi; . It is endemic in South and Central America and recently has been found in other parts of the world, due to migration of chronically infected patients. The current treatment for Chagas disease is not satisfactory, and there is a need for new treatments. In this work, we describe the optimization of a hit compound resulting from the phenotypic screen of a library of compounds against; T. cruzi; . The compound series was optimized to the level where it had satisfactory pharmacokinetics to allow an efficacy study in a mouse model of Chagas disease. We were able to demonstrate efficacy in this model, although further work is required to improve the potency and selectivity of this series

Repositioning of a diaminothiazole series confirmed to target the cyclin-dependent kinase CRK12 for use in the treatment of African animal trypanosomiasis

African animal trypanosomiasis or nagana, caused principally by infection of the protozoan parasites Trypanosoma congolense and Trypanosoma vivax, is a major problem in cattle and other livestocks in sub-Saharan Africa. Current treatments are threatened by the emergence of drug resistance and there is an urgent need for new, effective drugs. Here, we report the repositioning of a compound series initially developed for the treatment of human African trypanosomiasis. A medicinal chemistry program, focused on deriving more soluble analogues, led to development of a lead compound capable of curing cattle infected with both T. congolense and T. vivax via intravenous dosing. Further optimization has the potential to yield a single-dose intramuscular treatment for this disease. Comprehensive mode of action studies revealed that the molecular target of this promising compound and related analogues is the cyclin-dependent kinase CRK12

Validation of Plasmodium falciparum dUTPase as the target of 5'-tritylated deoxyuridine analogues with anti-malarial activity

BACKGROUND: Malaria remains as a major global problem, being one of the infectious diseases that engender highest mortality across the world. Due to the appearance of resistance and the lack of an effective vaccine, the search of novel anti-malarials is required. Deoxyuridine 5'-triphosphate nucleotido-hydrolase (dUTPase) is responsible for the hydrolysis of dUTP to dUMP within the parasite and has been proposed as an essential step in pyrimidine metabolism by providing dUMP for thymidylate biosynthesis. In this work, efforts to validate dUTPase as a drug target in Plasmodium falciparum are reported. METHODS: To investigate the role of PfdUTPase in cell survival different strategies to generate knockout mutants were used. For validation of PfdUTPase as the intracellular target of four inhibitors of the enzyme, mutants overexpressing PfdUTPase and HsdUTPase were created and the IC50 for each cell line with each compound was determined. The effect of these compounds on dUTP and dTTP levels from P. falciparum was measured using a DNA polymerase assay. Detailed localization studies by indirect immunofluorescence microscopy and live cell imaging were also performed using a cell line overexpressing a Pfdut-GFP fusion protein. RESULTS:Different attempts of disruption of the dut gene of P. falciparum were unsuccessful while a 3' replacement construct could recombine correctly in the locus suggesting that the enzyme is essential. The four 5'-tritylated deoxyuridine analogues described are potent inhibitors of the P. falciparum dUTPase and exhibit antiplasmodial activity. Overexpression of the Plasmodium and human enzymes conferred resistance against selective compounds, providing chemical validation of the target and confirming that indeed dUTPase inhibition is involved in anti-malarial activity. In addition, incubation with these inhibitors was associated with a depletion of the dTTP pool corroborating the central role of dUTPase in dTTP synthesis. PfdUTPase is mainly localized in the cytosol. CONCLUSION: These results strongly confirm the pivotal and essential role of dUTPase in pyrimidine biosynthesis of P. falciparum intraerythrocytic stages

Treatment of chagas disease

The invention provides compounds of the formula: wherein L1 and L2 are independently selected from O and S; R1 is C3-C6straight or branched alkyl, C3-C7cycloalkyl, C5-C7cycloalkenyl, adamantly, phenyl or saturated heterocyclyl, any of which being optionally substituted; R2 is H, methyl or ethyl; R5 is NRxCORy, NRxRy, CH2COCH3, CH2C≡N, or a 5- or 6-membered heteroaryl group which is optionally substituted; X, Y and Z are independently N or CH; Rx is independently H or C1-C4alkyl; Ry is independently H, CrC4alkyl, phenyl or benzyl, either of which is optionally substituted; n is 0-3; salts, hydrates and N-oxides, wherein the optional substituents are further defined in the claims. The compounds have utility in the prophylaxis or treatment of trypanosomal diseases, such as T. cruzi (Chagas disease).Peer reviewedUniversity of Dundee, Medivir AB, Consejo Superior de Investigaciones Científicas (España), Swiss Tropical and Public Health Institute, Syngene International Limited PLCA1 Solicitud de patente con informe sobre el estado de la técnic

Investigation of acyclic uridine amide and 5'-amido nucleoside analogues as potential inhibitors of the Plasmodium falciparum dUTPase

Previously we have shown that trityl and diphenyl deoxyuridine derivatives and their acyclic analogues can inhibit Plasmodium falciparum dUTPase (PfdUTPase). We report the synthesis of conformationally restrained amide derivatives as inhibitors PfdUTPase, including both acyclic and cyclic examples. Activity was dependent on the orientation and location of the amide constraining group. In the case of the acyclic series, we were able to obtain amide-constrained analogues which showed similar or greater potency than the unconstrained analogues. Unfortunately these compounds showed lower selectivity in cellular assays

Design, Synthesis, and Evaluation of 5 '-Diphenyl Nucleoside Analogues as Inhibitors of the Plasmodium falciparum dUTPase

Deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase) is a potential drug target for malaria. We previously reported some 5'-tritylated deoxyuridine analogues (both cyclic and acyclic) as selective inhibitors of the Plasmodium falciparum dUTPase. Modelling studies indicated that it might be possible to replace the trityl group with a diphenyl moiety, as two of the phenyl groups are buried, whereas the third is exposed to solvent. Herein we report the synthesis and evaluation of some diphenyl analogues that have lower lipophilicity and molecular weight than the trityl lead compound. Co-crystal structures show that the diphenyl inhibitors bind in a similar manner to the corresponding trityl derivatives, with the two phenyl moieties occupying the predicted buried phenyl binding sites. The diphenyl compounds prepared show similar or slightly lower inhibition of PfdUTPase, and similar or weaker inhibition of parasite growth than the trityl compound

Repositioning of a Diaminothiazole Series Confirmed to Target the Cyclin-Dependent Kinase CRK12 for Use in the Treatment of African Animal Trypanosomiasis

Coordinates for the homology model of T. brucei CRK12 with compound 2 docked into the ATP site, as shown in Figure 5 within the article