RESUMO
Visceral leishmaniasis causes considerable mortality and morbidity in many parts of the world. There is an urgent need for the development of new, effective treatments for this disease. Here we describe the development of an anti-leishmanial drug-like chemical series based on a pyrazolopyrimidine scaffold. The leading compound from this series (7, DDD853651/GSK3186899) is efficacious in a mouse model of visceral leishmaniasis, has suitable physicochemical, pharmacokinetic and toxicological properties for further development, and has been declared a preclinical candidate. Detailed mode-of-action studies indicate that compounds from this series act principally by inhibiting the parasite cdc-2-related kinase 12 (CRK12), thus defining a druggable target for visceral leishmaniasis.
Assuntos
Quinases Ciclina-Dependentes/antagonistas & inibidores , Leishmania donovani/efeitos dos fármacos , Leishmania donovani/enzimologia , Leishmaniose Visceral/tratamento farmacológico , Leishmaniose Visceral/parasitologia , Terapia de Alvo Molecular , Pirazóis/farmacologia , Pirimidinas/farmacologia , Animais , Quinase 9 Dependente de Ciclina/química , Quinases Ciclina-Dependentes/química , Quinases Ciclina-Dependentes/metabolismo , Modelos Animais de Doenças , Humanos , Camundongos , Simulação de Acoplamento Molecular , Proteoma/efeitos dos fármacos , Proteômica , Pirazóis/química , Pirazóis/uso terapêutico , Pirimidinas/química , Pirimidinas/uso terapêutico , Reprodutibilidade dos Testes , Especificidade por SubstratoRESUMO
Visceral leishmaniasis (VL), caused by the protozoan parasites Leishmania donovani and Leishmania infantum, is one of the major parasitic diseases worldwide. There is an urgent need for new drugs to treat VL, because current therapies are unfit for purpose in a resource-poor setting. Here, we describe the development of a preclinical drug candidate, GSK3494245/DDD01305143/compound 8, with potential to treat this neglected tropical disease. The compound series was discovered by repurposing hits from a screen against the related parasite Trypanosoma cruzi Subsequent optimization of the chemical series resulted in the development of a potent cidal compound with activity against a range of clinically relevant L. donovani and L. infantum isolates. Compound 8 demonstrates promising pharmacokinetic properties and impressive in vivo efficacy in our mouse model of infection comparable with those of the current oral antileishmanial miltefosine. Detailed mode of action studies confirm that this compound acts principally by inhibition of the chymotrypsin-like activity catalyzed by the ß5 subunit of the L. donovani proteasome. High-resolution cryo-EM structures of apo and compound 8-bound Leishmania tarentolae 20S proteasome reveal a previously undiscovered inhibitor site that lies between the ß4 and ß5 proteasome subunits. This induced pocket exploits ß4 residues that are divergent between humans and kinetoplastid parasites and is consistent with all of our experimental and mutagenesis data. As a result of these comprehensive studies and due to a favorable developability and safety profile, compound 8 is being advanced toward human clinical trials.
Assuntos
Antiprotozoários/administração & dosagem , Leishmania donovani/efeitos dos fármacos , Leishmania infantum/efeitos dos fármacos , Leishmaniose Visceral/diagnóstico por imagem , Inibidores de Proteassoma/administração & dosagem , Proteínas de Protozoários/antagonistas & inibidores , Animais , Antiprotozoários/química , Sítios de Ligação , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Humanos , Leishmania donovani/química , Leishmania donovani/enzimologia , Leishmania infantum/química , Leishmania infantum/enzimologia , Leishmaniose Visceral/parasitologia , Masculino , Camundongos , Complexo de Endopeptidases do Proteassoma/química , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/química , Conformação Proteica , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismoRESUMO
Malaria and cryptosporidiosis, caused by apicomplexan parasites, remain major drivers of global child mortality. New drugs for the treatment of malaria and cryptosporidiosis, in particular, are of high priority; however, there are few chemically validated targets. The natural product cladosporin is active against blood- and liver-stage Plasmodium falciparum and Cryptosporidium parvum in cell-culture studies. Target deconvolution in P. falciparum has shown that cladosporin inhibits lysyl-tRNA synthetase (PfKRS1). Here, we report the identification of a series of selective inhibitors of apicomplexan KRSs. Following a biochemical screen, a small-molecule hit was identified and then optimized by using a structure-based approach, supported by structures of both PfKRS1 and C. parvum KRS (CpKRS). In vivo proof of concept was established in an SCID mouse model of malaria, after oral administration (ED90 = 1.5 mg/kg, once a day for 4 d). Furthermore, we successfully identified an opportunity for pathogen hopping based on the structural homology between PfKRS1 and CpKRS. This series of compounds inhibit CpKRS and C. parvum and Cryptosporidium hominis in culture, and our lead compound shows oral efficacy in two cryptosporidiosis mouse models. X-ray crystallography and molecular dynamics simulations have provided a model to rationalize the selectivity of our compounds for PfKRS1 and CpKRS vs. (human) HsKRS. Our work validates apicomplexan KRSs as promising targets for the development of drugs for malaria and cryptosporidiosis.
Assuntos
Criptosporidiose , Cryptosporidium parvum/enzimologia , Inibidores Enzimáticos/farmacologia , Lisina-tRNA Ligase/antagonistas & inibidores , Malária Falciparum , Plasmodium falciparum/enzimologia , Proteínas de Protozoários/antagonistas & inibidores , Animais , Criptosporidiose/tratamento farmacológico , Criptosporidiose/enzimologia , Modelos Animais de Doenças , Inibidores Enzimáticos/química , Humanos , Lisina-tRNA Ligase/metabolismo , Malária Falciparum/tratamento farmacológico , Malária Falciparum/enzimologia , Camundongos SCID , Proteínas de Protozoários/metabolismoRESUMO
There is an urgent need for new drugs to treat malaria, with broad therapeutic potential and novel modes of action, to widen the scope of treatment and to overcome emerging drug resistance. Here we describe the discovery of DDD107498, a compound with a potent and novel spectrum of antimalarial activity against multiple life-cycle stages of the Plasmodium parasite, with good pharmacokinetic properties and an acceptable safety profile. DDD107498 demonstrates potential to address a variety of clinical needs, including single-dose treatment, transmission blocking and chemoprotection. DDD107498 was developed from a screening programme against blood-stage malaria parasites; its molecular target has been identified as translation elongation factor 2 (eEF2), which is responsible for the GTP-dependent translocation of the ribosome along messenger RNA, and is essential for protein synthesis. This discovery of eEF2 as a viable antimalarial drug target opens up new possibilities for drug discovery.
Assuntos
Antimaláricos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Malária/parasitologia , Plasmodium/efeitos dos fármacos , Plasmodium/metabolismo , Biossíntese de Proteínas/efeitos dos fármacos , Quinolinas/farmacologia , Animais , Antimaláricos/administração & dosagem , Antimaláricos/efeitos adversos , Antimaláricos/farmacocinética , Descoberta de Drogas , Feminino , Estágios do Ciclo de Vida/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/parasitologia , Malária/tratamento farmacológico , Masculino , Modelos Moleculares , Fator 2 de Elongação de Peptídeos/antagonistas & inibidores , Fator 2 de Elongação de Peptídeos/metabolismo , Plasmodium/genética , Plasmodium/crescimento & desenvolvimento , Plasmodium berghei/efeitos dos fármacos , Plasmodium berghei/fisiologia , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/metabolismo , Plasmodium vivax/efeitos dos fármacos , Plasmodium vivax/metabolismo , Quinolinas/administração & dosagem , Quinolinas/química , Quinolinas/farmacocinéticaRESUMO
Mutations in PINK1, which impair its catalytic kinase activity, are causal for autosomal recessive early-onset Parkinson's disease (PD). Various studies have indicated that the activation of PINK1 could be a useful strategy in treating neurodegenerative diseases, such as PD. Herein, it is shown that the anthelmintic drug niclosamide and its analogues are capable of activating PINK1 in cells through the reversible impairment of the mitochondrial membrane potential. With these compounds, for the first time, it is demonstrated that the PINK1 pathway is active and detectable in primary neurons. These findings suggest that niclosamide and its analogues are robust compounds for the study of the PINK1 pathway and may hold promise as a therapeutic strategy in PD and related disorders.
Assuntos
Anti-Helmínticos/química , Anti-Helmínticos/farmacologia , Ativadores de Enzimas/química , Ativadores de Enzimas/farmacologia , Niclosamida/análogos & derivados , Niclosamida/farmacologia , Proteínas Quinases/metabolismo , Descoberta de Drogas , Células HeLa , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Transtornos Parkinsonianos/tratamento farmacológico , Transtornos Parkinsonianos/enzimologiaRESUMO
The clinical efficacy and safety of a drug is determined by its activity profile across many proteins in the proteome. However, designing drugs with a specific multi-target profile is both complex and difficult. Therefore methods to design drugs rationally a priori against profiles of several proteins would have immense value in drug discovery. Here we describe a new approach for the automated design of ligands against profiles of multiple drug targets. The method is demonstrated by the evolution of an approved acetylcholinesterase inhibitor drug into brain-penetrable ligands with either specific polypharmacology or exquisite selectivity profiles for G-protein-coupled receptors. Overall, 800 ligand-target predictions of prospectively designed ligands were tested experimentally, of which 75% were confirmed to be correct. We also demonstrate target engagement in vivo. The approach can be a useful source of drug leads when multi-target profiles are required to achieve either selectivity over other drug targets or a desired polypharmacology.
Assuntos
Desenho de Fármacos , Ligantes , Animais , Automação , Sistemas de Liberação de Medicamentos , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Modelos Teóricos , Fenômenos Farmacológicos , Reprodutibilidade dos TestesRESUMO
Phosphoinositide-dependent kinase-1 (PDK1) controls the activation of a subset of AGC kinases. Using a conditional knockout of PDK1 in haematopoietic cells, we demonstrate that PDK1 is essential for B cell development. B-cell progenitors lacking PDK1 arrested at the transition of pro-B to pre-B cells, due to a cell autonomous defect. Loss of PDK1 decreased the expression of the IgH chain in pro-B cells due to impaired recombination of the IgH distal variable segments, a process coordinated by the transcription factor Pax5. The expression of Pax5 in pre-B cells was decreased in PDK1 knockouts, which correlated with reduced expression of the Pax5 target genes IRF4, IRF8 and Aiolos. As a result, Ccnd3 is upregulated in PDK1 knockout pre-B cells and they have an impaired ability to undergo cell-cycle arrest, a necessary event for Ig light chain rearrangement. Instead, these cells underwent apoptosis that correlated with diminished expression of the pro-survival gene Bcl2A1. Reintroduction of both Pax5 and Bcl2A1 together into PDK1 knockout pro-B cells restored their ability to differentiate in vitro into mature B cells.
Assuntos
Linfócitos B/metabolismo , Pontos de Checagem do Ciclo Celular/fisiologia , Cadeias Pesadas de Imunoglobulinas/biossíntese , Cadeias Leves de Imunoglobulina/biossíntese , Proteínas Serina-Treonina Quinases/metabolismo , Recombinação V(D)J/fisiologia , Proteínas Quinases Dependentes de 3-Fosfoinositídeo , Animais , Linfócitos B/citologia , Ciclina D3/genética , Ciclina D3/metabolismo , Técnicas de Silenciamento de Genes , Fator de Transcrição Ikaros , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Leves de Imunoglobulina/genética , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/metabolismo , Camundongos , Camundongos Transgênicos , Antígenos de Histocompatibilidade Menor , Fator de Transcrição PAX5/genética , Fator de Transcrição PAX5/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Transativadores/genética , Transativadores/metabolismo , Regulação para Cima/fisiologiaRESUMO
African sleeping sickness or human African trypanosomiasis, caused by Trypanosoma brucei spp., is responsible for approximately 30,000 deaths each year. Available treatments for this disease are poor, with unacceptable efficacy and safety profiles, particularly in the late stage of the disease when the parasite has infected the central nervous system. Here we report the validation of a molecular target and the discovery of associated lead compounds with the potential to address this lack of suitable treatments. Inhibition of this target-T. brucei N-myristoyltransferase-leads to rapid killing of trypanosomes both in vitro and in vivo and cures trypanosomiasis in mice. These high-affinity inhibitors bind into the peptide substrate pocket of the enzyme and inhibit protein N-myristoylation in trypanosomes. The compounds identified have promising pharmaceutical properties and represent an opportunity to develop oral drugs to treat this devastating disease. Our studies validate T. brucei N-myristoyltransferase as a promising therapeutic target for human African trypanosomiasis.
Assuntos
Aciltransferases/antagonistas & inibidores , Antiparasitários/farmacologia , Antiparasitários/uso terapêutico , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/enzimologia , Tripanossomíase Africana/tratamento farmacológico , Tripanossomíase Africana/parasitologia , Aciltransferases/metabolismo , Aminopiridinas/química , Aminopiridinas/metabolismo , Aminopiridinas/farmacologia , Aminopiridinas/uso terapêutico , Animais , Antiparasitários/química , Antiparasitários/metabolismo , Ensaios Enzimáticos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Feminino , Humanos , Camundongos , Estrutura Molecular , Pirazóis/química , Pirazóis/metabolismo , Pirazóis/farmacologia , Pirazóis/uso terapêutico , Ratos , Sulfonamidas/química , Sulfonamidas/metabolismo , Sulfonamidas/farmacologia , Sulfonamidas/uso terapêutico , Fatores de Tempo , Trypanosoma brucei brucei/crescimento & desenvolvimentoRESUMO
The novel nitroimidazopyran agent (S)-PA-824 has potent antibacterial activity against Mycobacterium tuberculosis in vitro and in vivo and is currently in phase II clinical trials for tuberculosis (TB). In contrast to M. tuberculosis, where (R)-PA-824 is inactive, we report here that both enantiomers of PA-824 show potent parasiticidal activity against Leishmania donovani, the causative agent of visceral leishmaniasis (VL). In leishmania-infected macrophages, (R)-PA-824 is 6-fold more active than (S)-PA-824. Both des-nitro analogues are inactive, underlining the importance of the nitro group in the mechanism of action. Although the in vitro and in vivo pharmacological profiles of the two enantiomers are similar, (R)-PA-824 is more efficacious in the murine model of VL, with >99% suppression of parasite burden when administered orally at 100 mg kg of body weight(-1), twice daily for 5 days. In M. tuberculosis, (S)-PA-824 is a prodrug that is activated by a deazaflavin-dependent nitroreductase (Ddn), an enzyme which is absent in Leishmania spp. Unlike the case with nifurtimox and fexinidazole, transgenic parasites overexpressing the leishmania nitroreductase are not hypersensitive to either (R)-PA-824 or (S)-PA-824, indicating that this enzyme is not the primary target of these compounds. Drug combination studies in vitro indicate that fexinidazole and (R)-PA-824 are additive whereas (S)-PA-824 and (R)-PA-824 show mild antagonistic behavior. Thus, (R)-PA-824 is a promising candidate for late lead optimization for VL and may have potential for future use in combination therapy with fexinidazole, currently in phase II clinical trials against VL.
Assuntos
Antiprotozoários/farmacologia , Antiprotozoários/uso terapêutico , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Leishmaniose Visceral/tratamento farmacológico , Animais , Antiprotozoários/química , Antituberculosos/química , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Nitroimidazóis/química , Nitroimidazóis/farmacologia , Nitroimidazóis/uso terapêutico , EstereoisomerismoRESUMO
While treatment options for human African trypanosomiasis (HAT) have improved significantly, there is still a need for new drugs with eradication now a realistic possibility. Here, we report the development of 2,4-diaminothiazoles that demonstrate significant potency against Trypanosoma brucei, the causative agent of HAT. Using phenotypic screening to guide structure-activity relationships, potent drug-like inhibitors were developed. Proof of concept was established in an animal model of the hemolymphatic stage of HAT. To treat the meningoencephalitic stage of infection, compounds were optimized for pharmacokinetic properties, including blood-brain barrier penetration. However, in vivo efficacy was not achieved, in part due to compounds evolving from a cytocidal to a cytostatic mechanism of action. Subsequent studies identified a nonessential kinase involved in the inositol biosynthesis pathway as the molecular target of these cytostatic compounds. These studies highlight the need for cytocidal drugs for the treatment of HAT and the importance of static-cidal screening of analogues.
Assuntos
Citostáticos , Tripanossomicidas , Trypanosoma brucei brucei , Tripanossomíase Africana , Animais , Humanos , Tripanossomíase Africana/tratamento farmacológico , Tripanossomicidas/uso terapêutico , Tripanossomicidas/farmacocinética , Citostáticos/uso terapêutico , Barreira HematoencefálicaRESUMO
There is an urgent need for new treatments for Chagas disease, a parasitic infection which mostly impacts South and Central America. We previously reported on the discovery of GSK3494245/DDD01305143, a preclinical candidate for visceral leishmaniasis which acted through inhibition of the Leishmania proteasome. A related analogue, active against Trypanosoma cruzi, showed suboptimal efficacy in an animal model of Chagas disease, so alternative proteasome inhibitors were investigated. Screening a library of phenotypically active analogues against the T. cruzi proteasome identified an active, selective pyridazinone, the development of which is described herein. We obtained a cryo-EM co-structure of proteasome and a key inhibitor and used this to drive optimization of the compounds. Alongside this, optimization of the absorption, distribution, metabolism, and excretion (ADME) properties afforded a suitable compound for mouse efficacy studies. The outcome of these studies is discussed, alongside future plans to further understand the series and its potential to deliver a new treatment for Chagas disease.
Assuntos
Doença de Chagas , Leishmaniose Visceral , Tripanossomicidas , Trypanosoma cruzi , Camundongos , Animais , Inibidores de Proteassoma/farmacologia , Inibidores de Proteassoma/uso terapêutico , Complexo de Endopeptidases do Proteassoma , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Leishmaniose Visceral/tratamento farmacológico , Tripanossomicidas/farmacologia , Tripanossomicidas/uso terapêutico , Tripanossomicidas/químicaRESUMO
Approximately 6-7 million people around the world are estimated to be infected with Trypanosoma cruzi, the causative agent of Chagas disease. The current treatments are inadequate and therefore new medical interventions are urgently needed. In this paper we describe the identification of a series of disubstituted piperazines which shows good potency against the target parasite but is hampered by poor metabolic stability. We outline the strategies used to mitigate this issue such as lowering logD, bioisosteric replacements of the metabolically labile piperazine ring and use of plate-based arrays for quick diversity scoping. We discuss the success of these strategies within the context of this series and highlight the challenges faced in phenotypic programs when attempting to improve the pharmacokinetic profile of compounds whilst maintaining potency against the desired target.
Assuntos
Doença de Chagas , Trypanosoma cruzi , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Humanos , Piperazinas/farmacologiaRESUMO
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.
Assuntos
Trypanosoma congolense , Tripanossomíase Africana , Animais , Bovinos , Quinases Ciclina-Dependentes , Reposicionamento de Medicamentos , Trypanosoma vivax , Tripanossomíase Africana/tratamento farmacológico , Tripanossomíase Africana/parasitologia , Tripanossomíase Africana/veterináriaRESUMO
With increasing drug resistance in tuberculosis (TB) patient populations, there is an urgent need for new drugs. Ideally, new agents should work through novel targets so that they are unencumbered by preexisting clinical resistance to current treatments. Benzofuran 1 was identified as a potential lead for TB inhibiting a novel target, the thioesterase domain of Pks13. Although, having promising activity against Mycobacterium tuberculosis, its main liability was inhibition of the hERG cardiac ion channel. This article describes the optimization of the series toward a preclinical candidate. Despite improvements in the hERG liability in vitro, when new compounds were assessed in ex vivo cardiotoxicity models, they still induced cardiac irregularities. Further series development was stopped because of concerns around an insufficient safety window. However, the demonstration of in vivo activity for multiple series members further validates Pks13 as an attractive novel target for antitubercular drugs and supports development of alternative chemotypes.
Assuntos
Antituberculosos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Benzofuranos/farmacologia , Palmitoil-CoA Hidrolase/antagonistas & inibidores , Piperidinas/farmacologia , Policetídeo Sintases/antagonistas & inibidores , Benzofuranos/síntese química , Cardiotoxicidade , Descoberta de Drogas , Canal de Potássio ERG1 , Coração/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Modelos Moleculares , Mycobacterium tuberculosis/efeitos dos fármacos , Piperidinas/síntese química , Relação Estrutura-AtividadeRESUMO
Tuberculosis is a major global cause of both mortality and financial burden mainly in low and middle-income countries. Given the significant and ongoing rise of drug-resistant strains of Mycobacterium tuberculosis within the clinical setting, there is an urgent need for the development of new, safe and effective treatments. Here the development of a drug-like series based on a fused dihydropyrrolidino-pyrimidine scaffold is described. The series has been developed against M. tuberculosis lysyl-tRNA synthetase (LysRS) and cellular studies support this mechanism of action. DDD02049209, the lead compound, is efficacious in mouse models of acute and chronic tuberculosis and has suitable physicochemical, pharmacokinetic properties and an in vitro safety profile that supports further development. Importantly, preliminary analysis using clinical resistant strains shows no pre-existing clinical resistance towards this scaffold.
Assuntos
Lisina-tRNA Ligase , Mycobacterium tuberculosis , Tuberculose , Animais , Lisina-tRNA Ligase/química , Lisina-tRNA Ligase/genética , Lisina-tRNA Ligase/farmacologia , Camundongos , Mycobacterium tuberculosis/genética , Tuberculose/tratamento farmacológicoRESUMO
There is an urgent need for new treatments for visceral leishmaniasis (VL), a parasitic infection which impacts heavily large areas of East Africa, Asia, and South America. We previously reported on the discovery of GSK3494245/DDD01305143 (1) as a preclinical candidate for VL and, herein, we report on the medicinal chemistry program that led to its identification. A hit from a phenotypic screen was optimized to give a compound with in vivo efficacy, which was hampered by poor solubility and genotoxicity. The work on the original scaffold failed to lead to developable compounds, so an extensive scaffold-hopping exercise involving medicinal chemistry design, in silico profiling, and subsequent synthesis was utilized, leading to the preclinical candidate. The compound was shown to act via proteasome inhibition, and we report on the modeling of different scaffolds into a cryo-EM structure and the impact this has on our understanding of the series' structure-activity relationships.
Assuntos
Desenho de Fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/química , Proteínas de Protozoários/metabolismo , Animais , Antiprotozoários/química , Antiprotozoários/metabolismo , Antiprotozoários/farmacologia , Antiprotozoários/uso terapêutico , Sítios de Ligação , Linhagem Celular , Avaliação Pré-Clínica de Medicamentos , Meia-Vida , Humanos , Leishmania donovani/efeitos dos fármacos , Leishmania donovani/metabolismo , Leishmaniose Visceral/tratamento farmacológico , Leishmaniose Visceral/parasitologia , Camundongos , Simulação de Dinâmica Molecular , Complexo de Endopeptidases do Proteassoma/química , Inibidores de Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Inibidores de Proteassoma/uso terapêutico , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo , Proteínas de Protozoários/química , Piridinas/química , Piridinas/metabolismo , Piridinas/farmacologia , Piridinas/uso terapêutico , Solubilidade , Relação Estrutura-AtividadeRESUMO
With the emergence of multi-drug-resistant strains of Mycobacterium tuberculosis, there is a pressing need for new oral drugs with novel mechanisms of action. A number of scaffolds with potent anti-tubercular in vitro activity have been identified from phenotypic screening that appear to target MmpL3. However, the scaffolds are typically lipophilic, which facilitates partitioning into hydrophobic membranes, and several contain basic amine groups. Highly lipophilic basic amines are typically cytotoxic against mammalian cell lines and have associated off-target risks, such as inhibition of human ether-à-go-go related gene (hERG) and IKr potassium current modulation. The spirocycle compound 3 was reported to target MmpL3 and displayed promising efficacy in a murine model of acute tuberculosis (TB) infection. However, this highly lipophilic monobasic amine was cytotoxic and inhibited the hERG ion channel. Herein, the related spirocycles (1-2) are described, which were identified following phenotypic screening of the Eli Lilly corporate library against M. tuberculosis. The novel N-alkylated pyrazole portion offered improved physicochemical properties, and optimization led to identification of a zwitterion series, exemplified by lead 29, with decreased HepG2 cytotoxicity as well as limited hERG ion channel inhibition. Strains with mutations in MmpL3 were resistant to 29, and under replicating conditions, 29 demonstrated bactericidal activity against M. tuberculosis. Unfortunately, compound 29 had no efficacy in an acute model of TB infection; this was most likely due to the in vivo exposure remaining above the minimal inhibitory concentration for only a limited time.
RESUMO
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.