RESUMO
Recent development of benzoxaborole-based chemistry gave rise to a collection of compounds with great potential in targeting diverse infectious diseases, including human African Trypanosomiasis (HAT), a devastating neglected tropical disease. However, further medicinal development is largely restricted by a lack of insight into mechanism of action (MoA) in pathogenic kinetoplastids. We adopted a multidisciplinary approach, combining a high-throughput forward genetic screen with functional group focused chemical biological, structural biology and biochemical analyses, to tackle the complex MoAs of benzoxaboroles in Trypanosoma brucei. We describe an oxidative enzymatic pathway composed of host semicarbazide-sensitive amine oxidase and a trypanosomal aldehyde dehydrogenase TbALDH3. Two sequential reactions through this pathway serve as the key underlying mechanism for activating a series of 4-aminomethylphenoxy-benzoxaboroles as potent trypanocides; the methylamine parental compounds as pro-drugs are transformed first into intermediate aldehyde metabolites, and further into the carboxylate metabolites as effective forms. Moreover, comparative biochemical and crystallographic analyses elucidated the catalytic specificity of TbALDH3 towards the benzaldehyde benzoxaborole metabolites as xenogeneic substrates. Overall, this work proposes a novel drug activation mechanism dependent on both host and parasite metabolism of primary amine containing molecules, which contributes a new perspective to our understanding of the benzoxaborole MoA, and could be further exploited to improve the therapeutic index of antimicrobial compounds.
Assuntos
Aldeído Desidrogenase/metabolismo , Amina Oxidase (contendo Cobre)/metabolismo , Compostos de Boro/metabolismo , Modelos Biológicos , Pró-Fármacos/metabolismo , Tripanossomicidas/metabolismo , Trypanosoma brucei brucei/enzimologia , Ativação Metabólica , Aldeído Desidrogenase/antagonistas & inibidores , Aldeído Desidrogenase/química , Aldeído Desidrogenase/genética , Aldeído Oxirredutases/antagonistas & inibidores , Aldeído Oxirredutases/química , Aldeído Oxirredutases/genética , Aldeído Oxirredutases/metabolismo , Amina Oxidase (contendo Cobre)/antagonistas & inibidores , Amina Oxidase (contendo Cobre)/química , Amina Oxidase (contendo Cobre)/genética , Substituição de Aminoácidos , Animais , Compostos de Boro/química , Compostos de Boro/farmacologia , Resistência a Medicamentos , Ensaios de Triagem em Larga Escala , Humanos , Estrutura Molecular , Mutação , Filogenia , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Domínios e Motivos de Interação entre Proteínas , Interferência de RNA , Ratos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Relação Estrutura-Atividade , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/fisiologiaRESUMO
Novel l-valinate amide benzoxaboroles and analogues were designed and synthesized for a structure-activity-relationship (SAR) investigation to optimize the growth inhibitory activity against Trypanosoma congolense (T. congolense) and Trypanosoma vivax (T. vivax) parasites. The study identified 4-fluorobenzyl (1-hydroxy-7-methyl-1,3-dihydrobenzo[c][1,2]oxaborole-6-carbonyl)-l-valinate (5, AN11736), which showed IC50 values of 0.15â¯nM against T. congolense and 1.3â¯nM against T. vivax, and demonstrated 100% efficacy with a single dose of 10â¯mg/kg against both T. congolense and T. vivax in mouse models of infection (IP dosing) and in the target animal, cattle, dosed intramuscularly. AN11736 has been advanced to early development studies.
Assuntos
Antiprotozoários/síntese química , Compostos de Boro/síntese química , Tripanossomíase Africana/tratamento farmacológico , Valina/análogos & derivados , Animais , Antiprotozoários/farmacologia , Antiprotozoários/uso terapêutico , Compostos de Boro/farmacologia , Compostos de Boro/uso terapêutico , Bovinos , Camundongos , Relação Estrutura-Atividade , Trypanosoma congolense/efeitos dos fármacos , Trypanosoma vivax/efeitos dos fármacos , Tripanossomíase Africana/patologia , Tripanossomíase Africana/veterinária , Valina/síntese química , Valina/farmacologia , Valina/uso terapêuticoRESUMO
There is a need for new antimalarials, ideally with novel mechanisms of action. Benzoxaboroles have been shown to be active against bacteria, fungi, and trypanosomes. Therefore, we investigated the antimalarial activity and mechanism of action of 3-aminomethyl benzoxaboroles against Plasmodium falciparum Two 3-aminomethyl compounds, AN6426 and AN8432, demonstrated good potency against cultured multidrug-resistant (W2 strain) P. falciparum (50% inhibitory concentration [IC50] of 310 nM and 490 nM, respectively) and efficacy against murine Plasmodium berghei infection when administered orally once daily for 4 days (90% effective dose [ED90], 7.4 and 16.2 mg/kg of body weight, respectively). To characterize mechanisms of action, we selected parasites with decreased drug sensitivity by culturing with stepwise increases in concentration of AN6426. Resistant clones were characterized by whole-genome sequencing. Three generations of resistant parasites had polymorphisms in the predicted editing domain of the gene encoding a P. falciparum leucyl-tRNA synthetase (LeuRS; PF3D7_0622800) and in another gene (PF3D7_1218100), which encodes a protein of unknown function. Solution of the structure of the P. falciparum LeuRS editing domain suggested key roles for mutated residues in LeuRS editing. Short incubations with AN6426 and AN8432, unlike artemisinin, caused dose-dependent inhibition of [(14)C]leucine incorporation by cultured wild-type, but not resistant, parasites. The growth of resistant, but not wild-type, parasites was impaired in the presence of the unnatural amino acid norvaline, consistent with a loss of LeuRS editing activity in resistant parasites. In summary, the benzoxaboroles AN6426 and AN8432 offer effective antimalarial activity and act, at least in part, against a novel target, the editing domain of P. falciparum LeuRS.
Assuntos
Antimaláricos/farmacologia , Leucina-tRNA Ligase/metabolismo , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/efeitos dos fármacos , Compostos de Boro/farmacologia , Resistência a Medicamentos/efeitos dos fármacos , Concentração Inibidora 50 , Malária Falciparum/parasitologia , Plasmodium falciparum/metabolismoRESUMO
The apicomplexan parasites Cryptosporidium and Toxoplasma are serious threats to human health. Cryptosporidiosis is a severe diarrheal disease in malnourished children and immunocompromised individuals, with the only FDA-approved drug treatment currently being nitazoxanide. The existing therapies for toxoplasmosis, an important pathology in immunocompromised individuals and pregnant women, also have serious limitations. With the aim of developing alternative therapeutic options to address these health problems, we tested a number of benzoxaboroles, boron-containing compounds shown to be active against various infectious agents, for inhibition of the growth of Cryptosporidium parasites in mammalian cells. A 3-aminomethyl benzoxaborole, AN6426, with activity in the micromolar range and with activity comparable to that of nitazoxanide, was identified and further characterized using biophysical measurements of affinity and crystal structures of complexes with the editing domain of Cryptosporidium leucyl-tRNA synthetase (LeuRS). The same compound was shown to be active against Toxoplasma parasites, with the activity being enhanced in the presence of norvaline, an amino acid that can be mischarged by LeuRS. Our observations are consistent with AN6426 inhibiting protein synthesis in both Cryptosporidium and Toxoplasma by forming a covalent adduct with tRNA(Leu) in the LeuRS editing active site and suggest that further exploitation of the benzoxaborole scaffold is a valid strategy to develop novel, much needed antiparasitic agents.
Assuntos
Antiprotozoários/farmacologia , Compostos de Boro/farmacologia , Cryptosporidium parvum/efeitos dos fármacos , Leucina-tRNA Ligase/antagonistas & inibidores , Leucina-tRNA Ligase/química , Toxoplasma/efeitos dos fármacos , Animais , Antiprotozoários/química , Antiprotozoários/metabolismo , Compostos de Boro/química , Cristalografia por Raios X , Cães , Avaliação Pré-Clínica de Medicamentos/métodos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/parasitologia , Humanos , Leucina-tRNA Ligase/metabolismo , Células Madin Darby de Rim Canino/parasitologia , Simulação de Acoplamento Molecular , Conformação ProteicaRESUMO
Gram-negative bacteria cause approximately 70% of the infections in intensive care units. A growing number of bacterial isolates responsible for these infections are resistant to currently available antibiotics and to many in development. Most agents under development are modifications of existing drug classes, which only partially overcome existing resistance mechanisms. Therefore, new classes of Gram-negative antibacterials with truly novel modes of action are needed to circumvent these existing resistance mechanisms. We have previously identified a new a way to inhibit an aminoacyl-tRNA synthetase, leucyl-tRNA synthetase (LeuRS), in fungi via the oxaborole tRNA trapping (OBORT) mechanism. Herein, we show how we have modified the OBORT mechanism using a structure-guided approach to develop a new boron-based antibiotic class, the aminomethylbenzoxaboroles, which inhibit bacterial leucyl-tRNA synthetase and have activity against Gram-negative bacteria by largely evading the main efflux mechanisms in Escherichia coli and Pseudomonas aeruginosa. The lead analogue, AN3365, is active against Gram-negative bacteria, including Enterobacteriaceae bearing NDM-1 and KPC carbapenemases, as well as P. aeruginosa. This novel boron-based antibacterial, AN3365, has good mouse pharmacokinetics and was efficacious against E. coli and P. aeruginosa in murine thigh infection models, which suggest that this novel class of antibacterials has the potential to address this unmet medical need.
Assuntos
Aminoacil-tRNA Sintetases/antagonistas & inibidores , Antibacterianos/farmacologia , Compostos de Boro/farmacologia , Escherichia coli/efeitos dos fármacos , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Pseudomonas aeruginosa/efeitos dos fármacos , Aminoacil-tRNA Sintetases/metabolismo , Animais , Antibacterianos/síntese química , Antibacterianos/farmacocinética , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/metabolismo , Compostos de Boro/síntese química , Compostos de Boro/farmacocinética , Cristalografia por Raios X , Descoberta de Drogas , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Escherichia coli/enzimologia , Feminino , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Leucina/metabolismo , Camundongos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Pseudomonas aeruginosa/enzimologia , Relação Estrutura-Atividade , Coxa da Perna/microbiologia , Inibidores de beta-Lactamases , beta-Lactamases/metabolismoRESUMO
Pro-inflammatory cytokines play a critical role in the development of autoimmune and inflammatory diseases. Targeting the cytokine environment has proven efficient for averting inflammation. In this study, we reported that 6-[4-(aminomethyl)-2-chlorophenoxyl]benzo[c][1,2]oxaborol-1(3H)-ol (AN3485), a benzoxaborole analog, inhibited TLR2-, TLR3-, TLR4-, and TLR5-mediated TNF-α, IL-1ß, and IL-6 release from human PBMCs and isolated monocytes with IC(50) values ranging from 18 to 580 nM, and the inhibition was mediated at the transcriptional level. Topical administration of AN3485 significantly reduced PMA-induced contact dermatitis and oxazolone-induced delayed-type hypersensitivity in mice, indicating its capability of penetrating skin and potential topical application in skin inflammation. Oral administration of AN3485 showed dose-dependent suppression of LPS-induced TNF-α and IL-6 production in mice with an ED(90) of 30 mg/kg. Oral AN3485, 35 mg/kg, twice a day, suppressed collagen-induced arthritis in mice over a 20-day period. The potent anti-inflammatory activity in in vitro and in vivo disease models makes AN3485 an attractive therapeutic lead for a variety of cutaneous and systemic inflammatory diseases.
Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Artrite/tratamento farmacológico , Compostos de Boro/uso terapêutico , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Dermatite Alérgica de Contato/tratamento farmacológico , Hipersensibilidade a Drogas/tratamento farmacológico , Hipersensibilidade Tardia/tratamento farmacológico , Receptores Toll-Like/antagonistas & inibidores , Administração Oral , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/farmacocinética , Anti-Inflamatórios não Esteroides/toxicidade , Artrite/imunologia , Artrite/metabolismo , Compostos de Boro/administração & dosagem , Compostos de Boro/farmacocinética , Compostos de Boro/toxicidade , Compostos Bicíclicos Heterocíclicos com Pontes/administração & dosagem , Compostos Bicíclicos Heterocíclicos com Pontes/farmacocinética , Compostos Bicíclicos Heterocíclicos com Pontes/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Citocinas/biossíntese , Citocinas/metabolismo , Dermatite Alérgica de Contato/etiologia , Dermatite Alérgica de Contato/imunologia , Dermatite Alérgica de Contato/metabolismo , Relação Dose-Resposta a Droga , Hipersensibilidade a Drogas/etiologia , Hipersensibilidade a Drogas/imunologia , Hipersensibilidade a Drogas/metabolismo , Feminino , Humanos , Hipersensibilidade Tardia/induzido quimicamente , Hipersensibilidade Tardia/imunologia , Hipersensibilidade Tardia/metabolismo , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos BALB CRESUMO
Structure-activity relationships of 6-(benzoylamino)benzoxaborole analogs were investigated for the inhibition of TNF-α, IL-1ß, and IL-6 from lipopolysaccharide stimulated peripheral blood mononuclear cells. Compound 1q showed potent activity against all three cytokines with IC50 values between 0.19 and 0.50µM, inhibited LPS-induced TNF-α and IL-6 elevation in mice and improved collagen-induced arthritis in mice. Compound 1q (AN4161) is considered to be a promising lead for novel anti-inflammatory agent with an excellent pharmacokinetic profile.
Assuntos
Anti-Inflamatórios/química , Anti-Inflamatórios/uso terapêutico , Artrite Experimental/tratamento farmacológico , Derivados de Benzeno/química , Derivados de Benzeno/uso terapêutico , Compostos de Boro/química , Compostos de Boro/uso terapêutico , Animais , Anti-Inflamatórios/farmacocinética , Anti-Inflamatórios/farmacologia , Derivados de Benzeno/farmacocinética , Derivados de Benzeno/farmacologia , Compostos de Boro/farmacocinética , Compostos de Boro/farmacologia , Interleucina-1beta/imunologia , Interleucina-6/imunologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Lipopolissacarídeos/imunologia , Camundongos , Relação Estrutura-Atividade , Fator de Necrose Tumoral alfa/imunologiaRESUMO
A series of novel 6-(aminomethylphenoxy)benzoxaborole analogs was synthesized for the investigation of the structure-activity relationship of the inhibition of TNF-alpha, IL-1beta, and IL-6, from lipopolysaccharide stimulated peripheral blood mononuclear cells. Compounds 9d and 9e showed potent activity against all three cytokines with IC50 values between 33 and 83nM. Chloro substituted analog 9e (AN3485) is considered to be a promising lead for novel anti-inflammatory agent with a favorable pharmacokinetic profile.
Assuntos
Anti-Inflamatórios/química , Benzoxazóis/química , Compostos de Boro/química , Compostos Bicíclicos Heterocíclicos com Pontes/metabolismo , Animais , Anti-Inflamatórios/metabolismo , Anti-Inflamatórios/farmacocinética , Compostos de Boro/metabolismo , Compostos de Boro/farmacocinética , Compostos Bicíclicos Heterocíclicos com Pontes/química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacocinética , Meia-Vida , Humanos , Interleucina-1beta/antagonistas & inibidores , Interleucina-1beta/metabolismo , Interleucina-6/antagonistas & inibidores , Interleucina-6/metabolismo , Cinética , Leucócitos Mononucleares/efeitos dos fármacos , Lipopolissacarídeos/toxicidade , Camundongos , Ligação Proteica , Relação Estrutura-Atividade , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/metabolismoRESUMO
A series of new boron-containing benzoxaborole compounds was designed and synthesized for a continuing structure-activity relationship (SAR) investigation to assess the antimalarial activity changes derived from side-chain structural variation, substituent modification on the benzene ring and removal of boron from five-membered oxaborole ring. This SAR study demonstrated that boron is required for the antimalarial activity, and discovered that three fluoro-substituted 7-(2-carboxyethyl)-1,3-dihydro-1-hydroxy-2,1-benzoxaboroles (9, 14 and 20) have excellent potencies (IC(50) 0.026-0.209 µM) against Plasmodium falciparum.
Assuntos
Antimaláricos/síntese química , Antimaláricos/farmacologia , Compostos de Boro/síntese química , Compostos de Boro/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Flúor/química , Plasmodium falciparum/efeitos dos fármacos , Antimaláricos/química , Antimaláricos/toxicidade , Compostos de Boro/química , Compostos de Boro/toxicidade , Compostos Bicíclicos Heterocíclicos com Pontes/química , Compostos Bicíclicos Heterocíclicos com Pontes/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Células HeLa , Humanos , Concentração Inibidora 50 , Células Jurkat , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
A series of boron-containing benzoxaborole compounds was designed and synthesized for a structure-activity relationship investigation surrounding 7-(HOOCCH(2)CH(2))-1,3-dihydro-1-hydroxy-2,1-benzoxaborole (1) with the goal of discovering a new antimalarial treatment. Compound 1 demonstrates the best potency (IC(50)=26nM) against Plasmodium falciparum and has good drug-like properties, with low molecular weight (206.00), low ClogP (0.86) and high water solubility (750µg/mL at pH 7).
Assuntos
Antimaláricos/química , Antimaláricos/farmacologia , Compostos de Boro/química , Compostos de Boro/farmacologia , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/efeitos dos fármacos , Antimaláricos/síntese química , Compostos de Boro/síntese química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Humanos , Testes de Sensibilidade Parasitária , Relação Estrutura-AtividadeRESUMO
New antimalarial drugs are needed. The benzoxaborole AN13762 showed excellent activity against cultured Plasmodium falciparum, against fresh Ugandan P. falciparum isolates, and in murine malaria models. To gain mechanistic insights, we selected in vitro for P. falciparum isolates resistant to AN13762. In all of 11 independent selections with 100 to 200 nM AN13762, the 50% inhibitory concentration (IC50) increased from 18-118 nM to 180-890 nM, and whole-genome sequencing of resistant parasites demonstrated mutations in prodrug activation and resistance esterase (PfPARE). The introduction of PfPARE mutations led to a similar level of resistance, and recombinant PfPARE hydrolyzed AN13762 to the benzoxaborole AN10248, which has activity similar to that of AN13762 but for which selection of resistance was not readily achieved. Parasites further selected with micromolar concentrations of AN13762 developed higher-level resistance (IC50, 1.9 to 5.0 µM), and sequencing revealed additional mutations in any of 5 genes, 4 of which were associated with ubiquitination/sumoylation enzyme cascades; the introduction of one of these mutations, in SUMO-activating enzyme subunit 2, led to a similar level of resistance. The other gene mutated in highly resistant parasites encodes the P. falciparum cleavage and specificity factor homolog PfCPSF3, previously identified as the antimalarial target of another benzoxaborole. Parasites selected for resistance to AN13762 were cross-resistant with a close analog, AN13956, but not with standard antimalarials, AN10248, or other benzoxaboroles known to have different P. falciparum targets. Thus, AN13762 appears to have a novel mechanism of antimalarial action and multiple mechanisms of resistance, including loss of function of PfPARE preventing activation to AN10248, followed by alterations in ubiquitination/sumoylation pathways or PfCPSF3.IMPORTANCE Benzoxaboroles are under study as potential new drugs to treat malaria. One benzoxaborole, AN13762, has potent activity and promising features, but its mechanisms of action and resistance are unknown. To gain insights into these mechanisms, we cultured malaria parasites with nonlethal concentrations of AN13762 and generated parasites with varied levels of resistance. Parasites with low-level resistance had mutations in PfPARE, which processes AN13762 into an active metabolite; PfPARE mutations prevented this processing. Parasites with high-level resistance had mutations in any of a number of enzymes, mostly those involved in stress responses. Parasites selected for AN13762 resistance were not resistant to other antimalarials, suggesting novel mechanisms of action and resistance for AN13762, a valuable feature for a new class of antimalarial drugs.
Assuntos
Antimaláricos/farmacologia , Resistência a Medicamentos , Malária Falciparum/parasitologia , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/metabolismo , Antimaláricos/química , Cromatografia Líquida , Análise Mutacional de DNA , Humanos , Espectrometria de Massas , Estrutura Molecular , Mutação , Polimorfismo de Nucleotídeo Único , Sumoilação/efeitos dos fármacos , Ubiquitinação/efeitos dos fármacosRESUMO
The elimination of filarial diseases such as onchocerciasis and lymphatic filariasis is hampered by the lack of a macrofilaricidal-adult worm killing-drug. In the present study, we tested the in vivo efficacy of AN11251, a boron-pleuromutilin that targets endosymbiotic Wolbachia bacteria from filarial nematodes and compared its efficacy to doxycycline and rifampicin. Doxycycline and rifampicin were previously shown to deplete Wolbachia endosymbionts leading to a permanent sterilization of the female adult filariae and adult worm death in human clinical studies. Twice-daily oral treatment of Litomosoides sigmodontis-infected mice with 200 mg/kg AN11251 for 10 days achieved a Wolbachia depletion > 99.9% in the adult worms, exceeding the Wolbachia reduction by 10-day treatments with bioequivalent human doses of doxycycline and a similar reduction as high-dose rifampicin (35 mg/kg). Wolbachia reductions of > 99% were also accomplished by 14 days of oral AN11251 at a lower twice-daily dose (50 mg/kg) or once-per-day 200 mg/kg AN11251 treatments. The combinations tested of AN11251 with doxycycline had no clear beneficial impact on Wolbachia depletion, achieving a > 97% Wolbachia reduction with 7 days of treatment. These results indicate that AN11251 is superior to doxycycline and comparable to high-dose rifampicin in the L. sigmodontis mouse model, allowing treatment regimens as short as 10-14 days. Therefore, AN11251 represents a promising pre-clinical candidate that was identified in the L. sigmodontis model, and could be further evaluated and developed as potential clinical candidate for human lymphatic filariasis and onchocerciasis.
Assuntos
Antibacterianos/farmacologia , Diterpenos/farmacologia , Filariose/tratamento farmacológico , Filarioidea/efeitos dos fármacos , Compostos Policíclicos/farmacologia , Wolbachia/efeitos dos fármacos , Animais , Boro , Doxiciclina/farmacologia , Feminino , Filariose/microbiologia , Filarioidea/microbiologia , Camundongos Endogâmicos BALB C , Rifampina/farmacologia , Simbiose , PleuromutilinasRESUMO
The optimization of a series of benzimidazole-benzoxaborole hybrid molecules linked via a ketone that exhibit good activity against Onchocerca volvulus, a filarial nematode responsible for the disease onchocerciasis, also known as river blindness, is described. The lead identified in this series, 21 (AN15470), was found to have acceptable pharmacokinetic properties to enable an evaluation following oral dosing in an animal model of onchocerciasis. Compound 21was effective in killing worms implanted in Mongolian gerbils when dosed orally as a suspension at 100 mg/kg/day for 14 days but not when dosed orally at 100 mg/kg/day for 7 days.
Assuntos
Benzimidazóis/uso terapêutico , Compostos de Boro/uso terapêutico , Cetonas/química , Oncocercose Ocular/tratamento farmacológico , Administração Oral , Animais , Benzimidazóis/farmacocinética , Compostos de Boro/farmacocinética , Modelos Animais de Doenças , Feminino , Filaricidas/farmacocinética , Filaricidas/uso terapêutico , Gerbillinae , MasculinoRESUMO
A series of benzimidazole-benzoxaborole hybrid molecules linked via an amide linker are described that exhibit good in vitro activity against Onchocerca volvulus, a filarial nematode responsible for the disease onchocerciasis, also known as river blindness. The lead identified in this series, 8a (AN8799), was found to have acceptable pharmacokinetic properties to enable evaluation in animal models of human filariasis. Compound 8a was effective in killing Brugia malayi, B. pahangi, and Litomosoides sigmodontis worms present in Mongolian gerbils when dosed subcutaneously as a suspension at 100 mg/kg/day for 14 days but not when dosed orally at 100 mg/kg/day for 28 days. The measurement of plasma levels of 8a at the end of the dosing period and at the time of sacrifice revealed an interesting dependence of activity on the extended exposure for both 8a and the positive control, flubendazole.
Assuntos
Benzimidazóis/uso terapêutico , Compostos de Boro/uso terapêutico , Brugia/efeitos dos fármacos , Oncocercose/tratamento farmacológico , Amidas , Animais , Benzimidazóis/farmacocinética , Compostos de Boro/farmacocinética , Feminino , Filaricidas/farmacocinética , Filaricidas/uso terapêutico , Gerbillinae , Masculino , Onchocerca volvulus/efeitos dos fármacosRESUMO
Cryptosporidiosis is a leading cause of life-threatening diarrhea in young children and causes chronic diarrhea in AIDS patients, but the only approved treatment is ineffective in malnourished children and immunocompromised people. We here use a drug repositioning strategy and identify a promising anticryptosporidial drug candidate. Screening a library of benzoxaboroles comprised of analogs to four antiprotozoal chemical scaffolds under pre-clinical development for neglected tropical diseases for Cryptosporidium growth inhibitors identifies the 6-carboxamide benzoxaborole AN7973. AN7973 blocks intracellular parasite development, appears to be parasiticidal, and potently inhibits the two Cryptosporidium species most relevant to human health, C. parvum and C. hominis. It is efficacious in murine models of both acute and established infection, and in a neonatal dairy calf model of cryptosporidiosis. AN7973 also possesses favorable safety, stability, and PK parameters, and therefore, is an exciting drug candidate for treating cryptosporidiosis.
Assuntos
Amidas/administração & dosagem , Antiprotozoários/administração & dosagem , Compostos de Boro/administração & dosagem , Criptosporidiose/tratamento farmacológico , Isoxazóis/administração & dosagem , Amidas/efeitos adversos , Amidas/química , Animais , Antiprotozoários/efeitos adversos , Antiprotozoários/química , Compostos de Boro/efeitos adversos , Compostos de Boro/química , Criptosporidiose/parasitologia , Cryptosporidium/efeitos dos fármacos , Cryptosporidium/crescimento & desenvolvimento , Avaliação Pré-Clínica de Medicamentos , Feminino , Humanos , Isoxazóis/efeitos adversos , Isoxazóis/química , Masculino , Camundongos , RatosRESUMO
A series of pleuromutilins modified by introduction of a boron-containing heterocycle on C(14) of the polycyclic core are described. These analogs were found to be potent anti- Wolbachia antibiotics and, as such, may be useful in the treatment of filarial infections caused by Onchocerca volvulus, resulting in Onchocerciasis or river blindness, or Wuchereria bancrofti and Brugia malayi and related parasitic nematodes resulting in lymphatic filariasis. These two important neglected tropical diseases disproportionately impact patients in the developing world. The lead preclinical candidate compound containing 7-fluoro-6-oxybenzoxaborole (15, AN11251) was shown to have good in vitro anti- Wolbachia activity and physicochemical and pharmacokinetic properties providing high exposure in plasma. The lead was effective in reducing the Wolbachia load in filarial worms following oral administration to mice.
Assuntos
Boro/farmacologia , Diterpenos/farmacologia , Filariose Linfática/tratamento farmacológico , Filaricidas/uso terapêutico , Oncocercose/tratamento farmacológico , Compostos Policíclicos/farmacologia , Wolbachia/efeitos dos fármacos , Wuchereria bancrofti/efeitos dos fármacos , Animais , Boro/química , Diterpenos/química , Filaricidas/farmacocinética , Filaricidas/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , Compostos Policíclicos/química , PleuromutilinasRESUMO
Toxoplasma gondii is an important food and waterborne pathogen causing toxoplasmosis, a potentially severe disease in immunocompromised or congenitally infected humans. Available therapeutic agents are limited by suboptimal efficacy and frequent side effects that can lead to treatment discontinuation. Here we report that the benzoxaborole AN3661 had potent in vitro activity against T. gondii Parasites selected to be resistant to AN3661 had mutations in TgCPSF3, which encodes a homologue of cleavage and polyadenylation specificity factor subunit 3 (CPSF-73 or CPSF3), an endonuclease involved in mRNA processing in eukaryotes. Point mutations in TgCPSF3 introduced into wild-type parasites using the CRISPR/Cas9 system recapitulated the resistance phenotype. Importantly, mice infected with T. gondii and treated orally with AN3661 did not develop any apparent illness, while untreated controls had lethal infections. Therefore, TgCPSF3 is a promising novel target of T. gondii that provides an opportunity for the development of anti-parasitic drugs.
Assuntos
Antiprotozoários/farmacologia , Compostos de Boro/farmacologia , Fator de Especificidade de Clivagem e Poliadenilação/antagonistas & inibidores , Toxoplasma/efeitos dos fármacos , Toxoplasma/enzimologia , Toxoplasmose/tratamento farmacológico , Administração Oral , Animais , Antiprotozoários/administração & dosagem , Compostos de Boro/administração & dosagem , Modelos Animais de Doenças , Resistência a Medicamentos , Camundongos , Testes de Sensibilidade Parasitária , Mutação Puntual , Análise de SobrevidaRESUMO
Carboxamide pyrazinyloxy benzoxaboroles were investigated with the goal to identify a molecule with satisfactory antimalarial activity, physicochemical properties, pharmacokinetic profile, in vivo efficacy, and safety profile. This optimization effort discovered 46, which met our target candidate profile. Compound 46 had excellent activity against cultured Plasmodium falciparum, and in vivo against P. falciparum and P. berghei in infected mice. It exhibited good PK properties in mice, rats, and dogs. It was highly active against the other 11 P. falciparum strains, which are mostly resistant to chloroquine and pyrimethamine. The rapid parasite in vitro reduction and in vivo parasite clearance profile of 46 were similar to those of artemisinin and chloroquine, two rapid-acting antimalarials. It was nongenotoxic in an Ames assay, an in vitro micronucleus assay, and an in vivo rat micronucleus assay when dosed orally up to 2000 mg/kg. The combined properties of this novel benzoxaborole support its progression to preclinical development.
Assuntos
Antimaláricos/química , Antimaláricos/farmacologia , Compostos de Boro/química , Compostos de Boro/farmacologia , Malária/tratamento farmacológico , Plasmodium berghei/efeitos dos fármacos , Plasmodium falciparum/efeitos dos fármacos , Amidas/química , Amidas/farmacocinética , Amidas/farmacologia , Amidas/uso terapêutico , Animais , Antimaláricos/farmacocinética , Antimaláricos/uso terapêutico , Compostos de Boro/farmacocinética , Compostos de Boro/uso terapêutico , Cães , Feminino , Humanos , Malária Falciparum/tratamento farmacológico , Masculino , Camundongos , Ratos , Ratos Sprague-Dawley , Relação Estrutura-AtividadeRESUMO
Benzoxaboroles are effective against bacterial, fungal and protozoan pathogens. We report potent activity of the benzoxaborole AN3661 against Plasmodium falciparum laboratory-adapted strains (mean IC50 32 nM), Ugandan field isolates (mean ex vivo IC50 64 nM), and murine P. berghei and P. falciparum infections (day 4 ED90 0.34 and 0.57 mg kg-1, respectively). Multiple P. falciparum lines selected in vitro for resistance to AN3661 harboured point mutations in pfcpsf3, which encodes a homologue of mammalian cleavage and polyadenylation specificity factor subunit 3 (CPSF-73 or CPSF3). CRISPR-Cas9-mediated introduction of pfcpsf3 mutations into parental lines recapitulated AN3661 resistance. PfCPSF3 homology models placed these mutations in the active site, where AN3661 is predicted to bind. Transcripts for three trophozoite-expressed genes were lost in AN3661-treated trophozoites, which was not observed in parasites selected or engineered for AN3661 resistance. Our results identify the pre-mRNA processing factor PfCPSF3 as a promising antimalarial drug target.
Assuntos
Antimaláricos/farmacologia , Compostos de Boro/farmacologia , Fator de Especificidade de Clivagem e Poliadenilação/química , Plasmodium falciparum/efeitos dos fármacos , Proteínas de Protozoários/química , RNA Mensageiro/genética , Sequência de Aminoácidos , Animais , Antimaláricos/síntese química , Compostos de Boro/síntese química , Sistemas CRISPR-Cas , Domínio Catalítico , Fator de Especificidade de Clivagem e Poliadenilação/antagonistas & inibidores , Fator de Especificidade de Clivagem e Poliadenilação/genética , Fator de Especificidade de Clivagem e Poliadenilação/metabolismo , Resistência a Medicamentos/genética , Eritrócitos/efeitos dos fármacos , Eritrócitos/parasitologia , Edição de Genes/métodos , Humanos , Malária/tratamento farmacológico , Malária/parasitologia , Malária Falciparum/tratamento farmacológico , Malária Falciparum/parasitologia , Camundongos , Simulação de Acoplamento Molecular , Mutação , Plasmodium berghei/efeitos dos fármacos , Plasmodium berghei/genética , Plasmodium berghei/crescimento & desenvolvimento , Plasmodium berghei/metabolismo , Plasmodium falciparum/genética , Plasmodium falciparum/crescimento & desenvolvimento , Plasmodium falciparum/metabolismo , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , Proteínas de Protozoários/antagonistas & inibidores , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Trofozoítos/efeitos dos fármacos , Trofozoítos/genética , Trofozoítos/crescimento & desenvolvimento , Trofozoítos/metabolismoRESUMO
A series of 6-hetaryloxy benzoxaborole compounds was designed and synthesized for a structure-activity relationship (SAR) investigation to assess the changes in antimalarial activity which result from 6-aryloxy structural variation, substituent modification on the pyrazine ring, and optimization of the side chain ester group. This SAR study discovered highly potent 6-(2-(alkoxycarbonyl)pyrazinyl-5-oxy)-1,3-dihydro-1-hydroxy-2,1-benzoxaboroles (9, 27-34) with IC50s = 0.2-22 nM against cultured Plasmodium falciparum W2 and 3D7 strains. Compound 9 also demonstrated excellent in vivo efficacy against P. berghei in infected mice (ED90 = 7.0 mg/kg).