RESUMO
BACKGROUND: Fostemsavir, a prodrug of the gp120-directed attachment inhibitor temsavir, is indicated for use in heavily treatment-experienced individuals with MDR HIV-1. Reduced susceptibility to temsavir in the clinic maps to discrete changes at amino acid positions in gp160: S375, M426, M434 and M475. OBJECTIVES: To query the Los Alamos National Laboratory (LANL) HIV Sequence Database for the prevalence of polymorphisms at gp160 positions of interest. METHODS: Full-length gp160 sequences (N = 7560) were queried for amino acid polymorphisms relative to the subtype B consensus at positions of interest; frequencies were reported for all sequences and among subtypes/circulating recombinant forms (CRFs) with ≥10 isolates in the database. RESULTS: Among 239 subtypes in the database, the 5 most prevalent were B (n = 2651, 35.1%), C (n = 1626, 21.5%), CRF01_AE (n = 674, 8.9%), A1 (n = 273, 3.6%) and CRF02_AG (n = 199, 2.6%). Among all 7560 sequences, the most prevalent amino acids at positions of interest (S375, 73.5%; M426, 82.1%; M434, 88.2%; M475, 89.9%) were the same as the subtype B consensus. Specific polymorphisms with the potential to decrease temsavir susceptibility (S375H/I/M/N/T/Y, M426L/P, M434I/K and M475I) were found in <10% of isolates of subtypes D, G, A6, BC, F1, CRF07_BC, CRF08_BC, 02A, CRF06_cpx, F2, 02G and 02B. S375H and M475I were predominant among CRF01_AE (S375H, 99.3%; M475I, 76.3%; consistent with previously reported low temsavir susceptibility of this CRF) and 01B (S375H, 71.7%; M475I, 49.5%). CONCLUSIONS: Analysis of the LANL HIV Sequence Database found a low prevalence of gp160 amino acid polymorphisms with the potential to reduce temsavir susceptibility overall and among most of the common subtypes.
Assuntos
Fármacos Anti-HIV , Farmacorresistência Viral/genética , Proteína gp160 do Envelope de HIV/genética , HIV-1 , Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , HIV-1/genética , Humanos , PrevalênciaRESUMO
GPR40 is a clinically validated molecular target for the treatment of diabetes. Many GPR40 agonists have been identified to date, with the partial agonist fasiglifam (TAK-875) reaching phase III clinical trials before its development was terminated due to off-target liver toxicity. Since then, attention has shifted toward the development of full agonists that exhibit superior efficacy in preclinical models. Full agonists bind to a distinct binding site, suggesting conformational plasticity and a potential for biased agonism. Indeed, it has been suggested that alternative pharmacology may be required for meaningful efficacy. In this study, we described the discovery and characterization of Compound A, a newly identified GPR40 allosteric full agonist highly efficacious in human islets at potentiating glucose-stimulated insulin secretion. We compared Compound A-induced GPR40 activity to that induced by both fasiglifam and AM-1638, another allosteric full agonist previously reported to be highly efficacious in preclinical models, at a panel of G proteins. Compound A was a full agonist at both the Gαq and Gαi2 pathways, and in contrast to fasiglifam Compound A also induced Gα12 coupling. Compound A and AM-1638 displayed similar activity at all pathways tested. The Gα12/Gα13-mediated signaling pathway has been linked to protein kinase D activation as well as actin remodeling, well known to contribute to the release of insulin vesicles. Our data suggest that the pharmacology of GPR40 is complex and that Gα12/Gα13-mediated signaling, which may contribute to GPR40 agonists therapeutic efficacy, is a specific property of GPR40 allosteric full agonists.
Assuntos
Subunidades alfa G12-G13 de Proteínas de Ligação ao GTP/metabolismo , Glucose/metabolismo , Secreção de Insulina/fisiologia , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Benzofuranos/farmacologia , Células CHO , Linhagem Celular , Cricetulus , Células HEK293 , Humanos , Hipoglicemiantes/farmacologia , Secreção de Insulina/efeitos dos fármacos , Ilhotas Pancreáticas/efeitos dos fármacos , Proteína Quinase C/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Sulfonas/farmacologiaRESUMO
Respiratory syncytial virus (RSV) is a leading cause of pneumonia and bronchiolitis in young children and the elderly. Therapeutic small molecules have been developed that bind the RSV F glycoprotein and inhibit membrane fusion, yet their binding sites and molecular mechanisms of action remain largely unknown. Here we show that these inhibitors bind to a three-fold-symmetric pocket within the central cavity of the metastable prefusion conformation of RSV F. Inhibitor binding stabilizes this conformation by tethering two regions that must undergo a structural rearrangement to facilitate membrane fusion. Inhibitor-escape mutations occur in residues that directly contact the inhibitors or are involved in the conformational rearrangements required to accommodate inhibitor binding. Resistant viruses do not propagate as well as wild-type RSV in vitro, indicating a fitness cost for inhibitor escape. Collectively, these findings provide new insight into class I viral fusion proteins and should facilitate development of optimal RSV fusion inhibitors.
Assuntos
Antivirais/farmacologia , Modelos Moleculares , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Proteínas Virais de Fusão/antagonistas & inibidores , Antivirais/química , Bioensaio , Colorimetria , Humanos , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Compound 12 is a GPR40 agonist that realizes the full magnitude of efficacy possible via GPR40 receptor agonism. In vitro and in vivo studies demonstrated superior glucose lowering by 12 compared to fasiglifam (TAK-875), in a glucose dependent manner. The enhanced efficacy observed with the full agonist 12 was associated with both direct and indirect stimulation of insulin secretion.
Assuntos
Hipoglicemiantes/farmacologia , Pirazinas/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Animais , Benzofuranos/farmacologia , Compostos de Bifenilo/farmacologia , Células CHO , Cricetulus , Cães , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Glucuronídeos/biossíntese , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/química , Hipoglicemiantes/metabolismo , Macaca fascicularis , Camundongos , Microssomos Hepáticos/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Fenilpropionatos/farmacologia , Piperidinas/farmacologia , Pirazinas/síntese química , Pirazinas/química , Pirazinas/metabolismo , Pirimidinas/farmacologia , Ratos , Relação Estrutura-Atividade , Sulfonas/farmacologiaRESUMO
GPR40 partial agonism is a promising new mechanism for the treatment of type 2 diabetes mellitus with clinical proof of concept. Most of the GPR40 agonists in the literature have a carboxylic acid functional group, which may pose a risk for idiosyncratic drug toxicity. A novel series of GPR40 agonists containing a tetrazole as a carboxylic acid bioisostere was identified. This series of compounds features a benzo[b]thiophene as the center ring, which is prone to oxidation during phase 1 metabolism. Following SAR optimization targeting GPR40 agonist activity and intrinsic clearance in microsomes (human and rat), potent and metabolically stable compounds were selected for in vivo evaluation. The compounds are efficacious at lowering blood glucose in a SD rat oGTT model.
Assuntos
Descoberta de Drogas , Receptores Acoplados a Proteínas G/agonistas , Tetrazóis/farmacologia , Tiofenos/farmacologia , Animais , Cães , Relação Dose-Resposta a Droga , Humanos , Modelos Moleculares , Estrutura Molecular , Ratos , Relação Estrutura-Atividade , Tetrazóis/síntese química , Tetrazóis/química , Tiofenos/químicaRESUMO
The discovery of a novel series of highly potent quinazoline TLR 7/8 agonists is described. The synthesis and structure-activity relationship is presented. Structural requirements and optimization of this series toward TLR 7 selectivity afforded the potent agonist 48. Pharmacokinetic and pharmacodynamic studies highlighted 48 as an orally available endogenous interferon (IFN-α) inducer in mice.
Assuntos
Glicoproteínas de Membrana/agonistas , Quinazolinas/farmacologia , Receptor 7 Toll-Like/agonistas , Animais , Inibidores das Enzimas do Citocromo P-450/síntese química , Inibidores das Enzimas do Citocromo P-450/química , Inibidores das Enzimas do Citocromo P-450/farmacocinética , Inibidores das Enzimas do Citocromo P-450/farmacologia , Células HEK293 , Meia-Vida , Humanos , Interferon-alfa/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Microssomos Hepáticos/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Quinazolinas/síntese química , Quinazolinas/química , Quinazolinas/farmacocinética , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Receptor 8 Toll-Like/agonistasRESUMO
Tuberculosis (TB) is more prevalent in the world today than at any other time in human history. Mycobacterium tuberculosis, the pathogen responsible for TB, uses diverse strategies to survive in a variety of host lesions and to evade immune surveillance. A key question is how robust are our approaches to discovering new TB drugs, and what measures could be taken to reduce the long and protracted clinical development of new drugs. The emergence of multi-drug-resistant strains of M. tuberculosis makes the discovery of new molecular scaffolds a priority, and the current situation even necessitates the re-engineering and repositioning of some old drug families to achieve effective control. Whatever the strategy used, success will depend largely on our proper understanding of the complex interactions between the pathogen and its human host. In this review, we discuss innovations in TB drug discovery and evolving strategies to bring newer agents more quickly to patients.
Assuntos
Antituberculosos/uso terapêutico , Descoberta de Drogas , Tuberculose/tratamento farmacológico , Antituberculosos/química , Antituberculosos/farmacologia , Respiração Celular/efeitos dos fármacos , Ensaios Clínicos como Assunto , Farmacorresistência Bacteriana , Resistência a Múltiplos Medicamentos , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Humanos , Mycobacterium tuberculosis/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacosRESUMO
Six-helix bundle (6HB) formation is an essential step for many viruses that rely on a class I fusion protein to enter a target cell and initiate replication. Because the binding modes of small molecule inhibitors of 6HB formation are largely unknown, precisely how they disrupt 6HB formation remains unclear, and structure-based design of improved inhibitors is thus seriously hampered. Here we present the high resolution crystal structure of TMC353121, a potent inhibitor of respiratory syncytial virus (RSV), bound at a hydrophobic pocket of the 6HB formed by amino acid residues from both HR1 and HR2 heptad-repeats. Binding of TMC353121 stabilizes the interaction of HR1 and HR2 in an alternate conformation of the 6HB, in which direct binding interactions are formed between TMC353121 and both HR1 and HR2. Rather than completely preventing 6HB formation, our data indicate that TMC353121 inhibits fusion by causing a local disturbance of the natural 6HB conformation.
Assuntos
Antivirais/metabolismo , Benzimidazóis/metabolismo , Piridinas/metabolismo , Vírus Sincicial Respiratório Humano/efeitos dos fármacos , Vírus Sincicial Respiratório Humano/metabolismo , Proteínas Virais de Fusão/química , Proteínas Virais de Fusão/metabolismo , Sequência de Aminoácidos , Antivirais/química , Antivirais/farmacologia , Benzimidazóis/química , Benzimidazóis/farmacologia , Fusão Celular , Cristalografia por Raios X , Células HeLa , Humanos , Fusão de Membrana/fisiologia , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Molecular , Estrutura Secundária de Proteína , Piridinas/química , Piridinas/farmacologia , Sequências Repetitivas de Aminoácidos , Vírus Sincicial Respiratório Humano/química , Alinhamento de Sequência , Relação Estrutura-Atividade , Proteínas Virais de Fusão/antagonistas & inibidores , Proteínas Virais de Fusão/genéticaRESUMO
Long-acting (LA) human immunodeficiency virus-1 (HIV-1) antiretroviral therapy characterized by a ≥1 month dosing interval offers significant advantages over daily oral therapy. However, the criteria for compounds that enter clinical development are high. Exceptional potency and low plasma clearance are required to meet dose size requirements; excellent chemical stability and/or crystalline form stability is required to meet formulation requirements, and new antivirals in HIV-1 therapy need to be largely free of side effects and drug-drug interactions. In view of these challenges, the discovery that capsid inhibitors comprising a quinazolinone core tolerate a wide range of structural modifications while maintaining picomolar potency against HIV-1 infection in vitro, are assembled efficiently in a multi-component reaction, and can be isolated in a stereochemically pure form is reported herein. The detailed characterization of a prototypical compound, GSK878, is presented, including an X-ray co-crystal structure and subcutaneous and intramuscular pharmacokinetic data in rats and dogs.
Assuntos
Fármacos Anti-HIV , Infecções por HIV , HIV-1 , Humanos , Ratos , Animais , Cães , Capsídeo , Proteínas do Capsídeo , Quinazolinonas/farmacologia , Quinazolinonas/uso terapêutico , Fármacos Anti-HIV/farmacocinética , Infecções por HIV/tratamento farmacológicoRESUMO
Mycobacterium tuberculosis infection results in more than two million deaths per year and is the leading cause of mortality in people infected with HIV. A new structural class of antimycobacterials, the diarylquinolines, has been synthesized and is being highly effective against both M. tuberculosis and multidrug-resistant tuberculosis. As diarylquinolines are biologically active only under their ( R,S) stereoisomeric form, it is essential to differentiate the stereoisomers ( R,S) and ( R,R). To achieve this, tandem mass spectrometry and ion mobility spectrometry-mass spectrometry have been performed with 10 diarylquinoline diastereomers couples. In this study, we investigated cationization with alkali metal cations and several ion mobility drift gases in order to obtain diastereomer differentiations. We have shown that diastereomers of the diarylquinolines family can be differentiated separately by tandem mass spectrometry and in mixture by ion mobility spectrometry-mass spectrometry. However, although the structure of each diastereomer is close, several behaviors could be observed concerning the cationization and the ion mobility spectrometry separation. The ion mobility spectrometry isomer separation efficiency is not easily predictable; it was however observed for all diastereomeric couples with a significant improvement of separation using alkali adducts compared to protonated molecules. With the use of drift gas with higher polarizability only an improvement of separation was obtained in a few cases. Finally, a good correlation of the experimental collision cross section (relative to three-dimensional structure of ions) and the theoretical collision cross section has been shown.
Assuntos
Antituberculosos/química , Diarilquinolinas/química , Espectrometria de Mobilidade Iônica/métodos , Antituberculosos/uso terapêutico , Diarilquinolinas/uso terapêutico , Humanos , Estrutura Molecular , Estereoisomerismo , Tuberculose/tratamento farmacológicoRESUMO
The gut hormone PYY3-36 reduces food intake in humans and exhibits at least additive efficacy in combination with GLP-1. However, the utility of PYY analogs as anti-obesity agents has been severely limited by emesis and rapid proteolysis, a profile similarly observed with native PYY3-36 in obese rhesus macaques. Here, we found that antibody conjugation of a cyclized PYY3-36 analog achieved high NPY2R selectivity, unprecedented in vivo stability, and gradual infusion-like exposure. These properties permitted profound reduction of food intake when administered to macaques for 23 days without a single emetic event in any animal. Co-administration with the GLP-1 receptor agonist liraglutide for an additional 5 days further reduced food intake with only one animal experiencing a single bout of emesis. This antibody-conjugated PYY analog therefore may enable the long-sought potential of GLP-1/PYY-based combination treatment to achieve robust, well-tolerated weight reduction in obese patients.
Assuntos
Anorexia/induzido quimicamente , Peptídeo YY/química , Peptídeo YY/farmacologia , Vômito , Animais , Células CHO , Cricetulus , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Células HEK293 , Humanos , Liraglutida/farmacologia , Macaca mulatta , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Peptídeo YY/administração & dosagem , Vômito/induzido quimicamenteRESUMO
We previously reported the discovery of substituted benzimidazole fusion inhibitors with nanomolar activity against respiratory syncytial virus (Andries, K.; et al. Antiviral Res. 2003, 60, 209-219). A lead compound of the series was selected for preclinical evaluation. This drug candidate, JNJ-2408068 (formerly R170591, 1), showed long tissue retention times in several species (rat, dog, and monkey), creating cause for concern. We herein describe the optimization program to develop compounds with improved properties in terms of tissue retention. We have identified the aminoethyl-piperidine moiety as being responsible for the long tissue retention time of 1. We have investigated the replacement or the modification of this group, and we suggest that the pKa of this part of the molecules influences both the antiviral activity and the pharmacokinetic profile. We were able to identify new respiratory syncytial virus inhibitors with shorter half-lives in lung tissue.
Assuntos
Antivirais/síntese química , Benzimidazóis/síntese química , Piperidinas/síntese química , Piridinas/síntese química , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Proteínas Virais de Fusão/antagonistas & inibidores , Animais , Antivirais/farmacocinética , Antivirais/farmacologia , Benzimidazóis/farmacocinética , Benzimidazóis/farmacologia , Células HeLa , Humanos , Rim/metabolismo , Fígado/metabolismo , Pulmão/metabolismo , Masculino , Piperidinas/farmacocinética , Piperidinas/farmacologia , Piridinas/farmacocinética , Piridinas/farmacologia , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Distribuição TecidualRESUMO
Respiratory syncytial virus is a major cause of acute lower respiratory tract infection in young children, immunocompromised adults, and the elderly. Intervention with small-molecule antivirals specific for respiratory syncytial virus presents an important therapeutic opportunity, but no such compounds are approved today. Here we report the structure of JNJ-53718678 bound to respiratory syncytial virus fusion (F) protein in its prefusion conformation, and we show that the potent nanomolar activity of JNJ-53718678, as well as the preliminary structure-activity relationship and the pharmaceutical optimization strategy of the series, are consistent with the binding mode of JNJ-53718678 and other respiratory syncytial virus fusion inhibitors. Oral treatment of neonatal lambs with JNJ-53718678, or with an equally active close analog, efficiently inhibits established acute lower respiratory tract infection in the animals, even when treatment is delayed until external signs of respiratory syncytial virus illness have become visible. Together, these data suggest that JNJ-53718678 is a promising candidate for further development as a potential therapeutic in patients at risk to develop respiratory syncytial virus acute lower respiratory tract infection.Respiratory syncytial virus causes lung infections in children, immunocompromised adults, and in the elderly. Here the authors show that a chemical inhibitor to a viral fusion protein is effective in reducing viral titre and ameliorating infection in rodents and neonatal lambs.
Assuntos
Imidazolidinas/metabolismo , Indóis/metabolismo , Vírus Sincicial Respiratório Humano/metabolismo , Inibidores de Proteínas Virais de Fusão/metabolismo , Proteínas Virais de Fusão/metabolismo , Animais , Animais Recém-Nascidos , Linhagem Celular Tumoral , Chlorocebus aethiops , Células Epiteliais , Humanos , Imidazolidinas/farmacologia , Imidazolidinas/uso terapêutico , Indóis/farmacologia , Indóis/uso terapêutico , Estrutura Molecular , Pneumonia Viral/tratamento farmacológico , Ratos , Mucosa Respiratória/citologia , Infecções por Vírus Respiratório Sincicial/tratamento farmacológico , Vírus Sincicial Respiratório Humano/efeitos dos fármacos , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Vírus Sinciciais Respiratórios/metabolismo , Ovinos , Relação Estrutura-Atividade , Células Vero , Inibidores de Proteínas Virais de Fusão/farmacologia , Inibidores de Proteínas Virais de Fusão/uso terapêuticoRESUMO
Pyrrolo[3,2-d]pyrimidines were identified as a new series of potent and selective TLR7 agonists. Compounds were optimized for their activity and selectivity over TLR8. This presents an advantage over recently described scaffolds that have residual TLR8 activity, which may be detrimental to the tolerability of the candidate drug. Oral administration of the lead compound 54 effectively induced a transient interferon stimulated gene (ISG) response in mice and cynomolgus monkeys. We aimed for a high first pass effect, limiting cytokine induction systemically, and demonstrated the potential for the immunotherapy of viral hepatitis.
Assuntos
Antivirais/síntese química , Hepatite B/tratamento farmacológico , Pirimidinas/síntese química , Pirróis/síntese química , Receptor 7 Toll-Like/agonistas , Administração Oral , Animais , Antivirais/farmacocinética , Antivirais/farmacologia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/metabolismo , Cães , Feminino , Genes Reporter , Células HEK293 , Hepatite B/imunologia , Humanos , Imunoterapia , Interferons/biossíntese , Macaca fascicularis , Células Madin Darby de Rim Canino , Camundongos Endogâmicos C57BL , Simulação de Acoplamento Molecular , Pirimidinas/farmacocinética , Pirimidinas/farmacologia , Pirróis/farmacocinética , Pirróis/farmacologia , Ratos , Relação Estrutura-Atividade , Receptor 7 Toll-Like/genética , Receptor 8 Toll-Like/agonistas , Receptor 8 Toll-Like/genéticaRESUMO
Toll-like receptor (TLR) 7 and 8 agonists can potentially be used in the treatment of viral infections and are particularly promising for chronic hepatitis B virus (HBV) infection. An internal screening effort identified a pyrimidine Toll-like receptor 7 and 8 dual agonist. This provided a novel alternative over the previously reported adenine and pteridone type of agonists. Structure-activity relationship, lead optimization, in silico docking, pharmacokinetics, and demonstration of ex vivo and in vivo cytokine production of the lead compound are presented.
Assuntos
Antivirais/química , Vírus da Hepatite B/efeitos dos fármacos , Pirimidinas/química , Receptor 7 Toll-Like/agonistas , Receptor 8 Toll-Like/agonistas , Animais , Antivirais/síntese química , Antivirais/farmacocinética , Antivirais/farmacologia , Simulação por Computador , Citocinas/biossíntese , Cães , Hepatite B/tratamento farmacológico , Hepatite B/virologia , Vírus da Hepatite B/fisiologia , Ensaios de Triagem em Larga Escala , Humanos , Macaca fascicularis , Camundongos , Camundongos Endogâmicos C57BL , Simulação de Acoplamento Molecular , Pirimidinas/síntese química , Pirimidinas/farmacocinética , Pirimidinas/farmacologia , Ratos Sprague-Dawley , Estereoisomerismo , Relação Estrutura-Atividade , Replicação Viral/efeitos dos fármacosRESUMO
To exploit available structural information about the cyclooxygenase enzyme for the virtual screening of large chemical libraries, a docking-scoring protocol was tuned and validated. The screening accuracy was assessed using a series of known inhibitors and a set of diverse a priori inactive compounds that was seeded with known active ligands. The major parameters of the DOCK algorithm were investigated. A large improvement of the results was obtained on tweaking some of them. The generated complexes were rescored using six scoring functions. In this way, the striking importance of this step was demonstrated, as well as the good performances of DOCK energy and SCORE for this target. The results were further improved via a consensus approach. As a first application, a subset of a large compound library was screened using this protocol. Among the compounds that were selected for biological testing, a third of them turned out to have a significant enzyme inhibition.
Assuntos
Inibidores de Ciclo-Oxigenase/química , Prostaglandina-Endoperóxido Sintases/química , Prostaglandina-Endoperóxido Sintases/metabolismo , Relação Quantitativa Estrutura-Atividade , Cristalografia por Raios X , Ciclo-Oxigenase 1 , Ciclo-Oxigenase 2 , Inibidores de Ciclo-Oxigenase 2 , Inibidores de Ciclo-Oxigenase/farmacologia , Bases de Dados Factuais , Humanos , Técnicas Imunoenzimáticas , Proteínas de Membrana , Conformação Molecular , Estrutura Molecular , Reprodutibilidade dos Testes , Sulfonamidas/química , Sulfonamidas/farmacologiaRESUMO
This paper reports the synthesis and antiviral properties of new difluoromethylbenzoxazole (DFMB) pyrimidine thioether derivatives as non-nucleoside HIV-1 reverse transcriptase inhibitors. By use of a combination of structural biology study and traditional medicinal chemistry, several members of this novel class were synthesized using a single electron transfer chain process (radical nucleophilic substitution, S(RN)1) and were found to be potent against wild-type HIV-1 reverse transcriptase, with low cytotoxicity but with moderate activity against drug-resistant strains. The most promising compound 24 showed a significant EC(50) value close to 6.4 nM against HIV-1 IIIB, a moderate EC(50) value close to 54 µM against an NNRTI resistant double mutant (K103N + Y181C), but an excellent selectivity index >15477 (CC(50) > 100 µM).
Assuntos
Fármacos Anti-HIV/síntese química , Benzoxazóis/síntese química , Transcriptase Reversa do HIV/metabolismo , Pirimidinas/síntese química , Inibidores da Transcriptase Reversa/síntese química , Sulfetos/síntese química , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Benzoxazóis/química , Benzoxazóis/farmacologia , Linhagem Celular Tumoral , Transcriptase Reversa do HIV/genética , HIV-1/efeitos dos fármacos , HIV-1/genética , Humanos , Mutação , Pirimidinas/química , Pirimidinas/farmacologia , Inibidores da Transcriptase Reversa/química , Inibidores da Transcriptase Reversa/farmacologia , Relação Estrutura-Atividade , Sulfetos/química , Sulfetos/farmacologiaRESUMO
Using classification (SOM, LVQ, Binary, Decision Tree) and regression algorithms (PLS, BRANN, k-NN, Linear), this paper details the building of eight 2D-QSAR models from a 266 COX-2 inhibitor training set. The predictive performances of these eight models were subsequently compared using an 88 COX-2 inhibitor test set. Each ligand is described by 52 2D descriptors expressed as van der Waals Surface Areas (P_VSA) and its COX-2 binding IC50. One of our best predictive models is the neural network model (BRANN), which is able to select a subset, from the 88 ligand test set, that contains 94% COX-2 active inhibitors (pIC50>7.5) and detects 71% of all the actives. We then introduce a QSAR consensus prediction protocol that is shown to be more predictive than any single QSAR model: our C3 consensus approach is able to select a subset from the 88 ligand test set that contains 94% active inhibitors and 83% of all the actives. The 2D QSAR consensus protocol was finally applied to the high-throughput virtual screening of the NCI database, containing 193,477 organic compounds.
Assuntos
Inibidores de Ciclo-Oxigenase/farmacologia , Sistemas de Gerenciamento de Base de Dados , Isoenzimas/efeitos dos fármacos , Prostaglandina-Endoperóxido Sintases/efeitos dos fármacos , Ciclo-Oxigenase 2 , Inibidores de Ciclo-Oxigenase 2 , National Institutes of Health (U.S.) , Relação Quantitativa Estrutura-Atividade , Estados UnidosRESUMO
The genome of all retroviruses consists of two identical copies of an RNA sequence associated in a non-covalent dimer. A region upstream from the splice donor (SL1) comprising a self-complementary sequence is responsible for the initiation of the dimerization. This region is able to dimerize in two conformations: a loop-loop complex or an extended duplex. Here, we solve by 2D NMR techniques the solution structure of a 23-nucleotide sequence corresponding to HIV-1 SL1(Lai) in which the mutation G12-->A12 is included to prevent dimerization. It is shown that this monomer adopts a stem-loop conformation with a seven base pairs stem and a nine nucleotide loop containing the G10 C11 A12 C13 G14 C15 sequence. The stem is well structured in an A-form duplex, while the loop is more flexible even though elements of structure are evident. We show that the structure adopted by the stem can be appreciably different from its relaxed structure when the adenines A8, A9 and A16 in the loop are mechanically constrained. This point could be important for the efficiency of the dimerization. This experimental study is complemented with a 10 ns molecular dynamics simulation in the presence of counterions and explicit water molecules. This simulation brings about information on the flexibility of the loop, such as a hinge motion between the stem and the loop and a labile lattice of hydrogen bonds in the loop. The bases of the nucleotides G10 to C15 were found outside of the loop during a part of the trajectory, which is certainly necessary to initiate the dimerization process of the genuine SL1(Lai) sequence.