RESUMO
Galectin-3 (Gal-3) is a carbohydrate binding protein that has been implicated in the development and progression of fibrotic diseases. Proof-of-principal animal models have demonstrated that inhibition of Gal-3 is a potentially viable pathway for the treatment of fibrosisâwith small molecule Gal-3 inhibitors advanced into clinical trials. We hereby report the discovery of novel galactose-based monosaccharide Gal-3 inhibitors comprising 2-methyl-4-phenyl-2,4-dihydro-3H-1,2,4-triazole-3-thione (compound 20) and 4-phenyl-4H-1,2,4-triazole (compound 15). Notably, hindered rotation caused by steric interaction between the 3-thione and ortho-trifluoromethyl group of compounds 20, 21 induced formation of thermodynamically stable atropisomers. Distinct X-ray cocrystal structures of 20 and 21 were obtained, which clearly demonstrated that the configuration of 21 proscribes a key halogen bonding σ-hole interaction of 3-chloro with carbonyl oxygen of Gly182, thereby leading to significant loss in potency. Ultimately, 20 and 15 were evaluated in mouse pharmacokinetic studies, and both compounds exhibited oral exposures suitable for further in vivo assessment.
RESUMO
Galectin-3 is a member of a family of ß-galactoside-binding proteins. A substantial body of literature reports that galectin-3 plays important roles in cancer, inflammation, and fibrosis. Small-molecule galectin-3 inhibitors, which are generally lactose or galactose-based derivatives, have the potential to be valuable disease-modifying agents. In our efforts to identify novel galectin-3 disaccharide mimics to improve drug-like properties, we found that one of the monosaccharide subunits can be replaced with a suitably functionalized tetrahydropyran ring. Optimization of the structure-activity relationships around the tetrahydropyran-based scaffold led to the discovery of potent galectin-3 inhibitors. Compounds 36, 40, and 45 were selected for further in vivo evaluation. The synthesis, structure-activity relationships, and in vivo evaluation of novel tetrahydropyran-based galectin-3 inhibitors are described.
Assuntos
Dissacarídeos/química , Galectina 3/antagonistas & inibidores , Piranos/química , Animais , Sítios de Ligação , Quimiotaxia/efeitos dos fármacos , Cristalografia por Raios X , Dissacarídeos/síntese química , Dissacarídeos/metabolismo , Dissacarídeos/farmacologia , Galectina 3/metabolismo , Meia-Vida , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Conformação Molecular , Simulação de Dinâmica Molecular , Permeabilidade/efeitos dos fármacos , Ligação Proteica , Relação Estrutura-Atividade , Triazóis/químicaRESUMO
GSK3532795 (formerly BMS-955176) is a second-generation HIV-1 maturation inhibitor that has shown broad spectrum antiviral activity and preclinical PK predictive of once-daily dosing in humans. Although efficacy was confirmed in clinical trials, the observation of gastrointestinal intolerability and the emergence of drug resistant virus in a Phase 2b clinical study led to the discontinuation of GSK3532795. As part of the effort to further map the maturation inhibitor pharmacophore and provide additional structural options, the evaluation of alternates to the C-3 phenyl substituent in this chemotype was pursued. A cyclohexene carboxylic acid provided exceptional inhibition of wild-type, V370A and ΔV370 mutant viruses in addition to a suitable PK profile following oral dosing to rats. In addition, a novel spiro[3.3]hept-5-ene was designed to extend the carboxylic acid further from the triterpenoid core while reducing side chain flexibility compared to the other alkyl substituents. This modification was shown to closely emulate the C-3 benzoic acid moiety of GSK3532795 from both a potency and PK perspective, providing a non-traditional, sp3-rich bioisostere of benzene. Herein, we detail additional modifications to the C-3 position of the triterpenoid core that offer effective replacements for the benzoic acid of GSK3532795 and capture the interplay between these new C-3 elements and C-17 modifications that contribute to enhanced polymorph coverage.
Assuntos
Fármacos Anti-HIV/farmacologia , Ácido Benzoico/farmacologia , Desenho de Fármacos , HIV-1/efeitos dos fármacos , Triterpenos/farmacologia , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/química , Ácido Benzoico/síntese química , Ácido Benzoico/química , Relação Dose-Resposta a Droga , Farmacorresistência Viral/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade , Triterpenos/síntese química , Triterpenos/químicaRESUMO
Programmed cell death-1 (PD-1), an antigen co-receptor on cell surfaces, is one of the conspicuous immune checkpoints. Nivolumab, a monoclonal antibody therapeutic approved by the FDA, binds to PD-1 and efficiently blocks its pathways. In this study, an integrated approach was developed to map the epitope/paratope of PD-1/nivolumab. The approach includes hydrogen-deuterium exchange mass spectrometry (HDX-MS) followed by electron-transfer dissociation (ETD), chemical cross-linking, and molecular docking. HDX-ETD offers some binding-site characterization with amino acid resolution. Chemical cross-linking provides complementary information on one additional epitope (i.e., the BC-loop) and a potential paratope at the N-terminus of the heavy chain. Furthermore, cross-linking identifies another loop region (i.e., the C'D-loop) that undergoes a remote conformational change. The distance restraints derived from the cross-links enable building high-confidence models of PD-1/nivolumab, evaluated with respect to a resolved crystal structure. This integrated strategy is an opportunity to characterize comprehensively other antigen-antibody interactions, to enable the understanding of binding mechanisms, and to design future antibody therapeutics.
Assuntos
Medição da Troca de Deutério , Mapeamento de Epitopos/métodos , Epitopos/análise , Nivolumabe/imunologia , Receptor de Morte Celular Programada 1/imunologia , Sequência de Aminoácidos , Complexo Antígeno-Anticorpo/química , Sítios de Ligação , Cromatografia Líquida de Alta Pressão , Epitopos/química , Epitopos/imunologia , Humanos , Simulação de Acoplamento Molecular , Nivolumabe/metabolismo , Receptor de Morte Celular Programada 1/química , Receptor de Morte Celular Programada 1/metabolismo , Ligação Proteica , Estrutura Secundária de Proteína , Espectrometria de Massas em TandemRESUMO
Mass spectrometry (MS)-based protein footprinting, a valuable structural tool in mapping protein-ligand interaction, has been extensively applied to protein-protein complexes, showing success in mapping large interfaces. Here, we utilized an integrated footprinting strategy incorporating both hydrogen-deuterium exchange (HDX) and hydroxyl radical footprinting (i.e., fast photochemical oxidation of proteins (FPOP)) for molecular-level characterization of the interaction of human bromodomain-containing protein 4 (BRD4) with a hydrophobic benzodiazepine inhibitor. HDX does not provide strong evidence for the location of the binding interface, possibly because the shielding of solvent by the small molecule is not large. Instead, HDX suggests that BRD4 appears to be stabilized by showing a modest decrease in dynamics caused by binding. In contrast, FPOP points to a critical binding region in the hydrophobic cavity, also identified by crystallography, and, therefore, exhibits higher sensitivity than HDX in mapping the interaction of BRD4 with compound 1. In the absence or under low concentrations of the radical scavenger, FPOP modifications on Met residues show significant differences that reflect the minor change in protein conformation. This problem can be avoided by using a sufficient amount of proper scavenger, as suggested by the FPOP kinetics directed by a dosimeter of the hydroxyl radical.
Assuntos
Benzodiazepinas/farmacologia , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/metabolismo , Espectrometria de Massas em Tandem/métodos , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/metabolismo , Benzodiazepinas/química , Proteínas de Ciclo Celular/química , Medição da Troca de Deutério/métodos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Radical Hidroxila/análise , Radical Hidroxila/metabolismo , Modelos Moleculares , Conformação Proteica/efeitos dos fármacos , Fatores de Transcrição/químicaRESUMO
We describe an integrated approach of using hydrogen-deuterium exchange mass spectrometry (HDX-MS), chemical cross-linking mass spectrometry (XL-MS), and molecular docking to characterize the binding interface and to predict the three-dimensional quaternary structure of a protein-protein complex in solution. Interleukin 7 (IL-7) and its α-receptor, IL-7Rα, serving as essential mediators in the immune system, are the model system. HDX kinetics reports widespread protection on IL-7Rα but shows no differential evidence of binding-induced protection or remote conformational change. Cross-linking with reagents that differ in spacer lengths and targeting residues increases the spatial resolution. Using five cross-links as distance restraints for protein-protein docking, we generated a high-confidence model of the IL-7/IL-7Rα complex. Both the predicted binding interface and regions with direct contacts agree well with those in the solid-state structure, as confirmed by previous X-ray crystallography. An additional binding region was revealed to be the C-terminus of helix B of IL-7, highlighting the value of solution-based characterization. To generalize the integrated approach, protein-protein docking was executed with a different number of cross-links. Combining cluster analysis and HDX kinetics adjudication, we found that two intermolecular cross-link-derived restraints are sufficient to generate a high-confidence model with root-mean-square distance (rmsd) value of all alpha carbons below 2.0 Å relative to the crystal structure. The remarkable results of binding-interface determination and quaternary structure prediction highlight the effectiveness and capability of the integrated approach, which will allow more efficient and comprehensive analysis of interprotein interactions with broad applications in the multiple stages of design, implementation, and evaluation for protein therapeutics.
Assuntos
Medição da Troca de Deutério/métodos , Hidrogênio/química , Interleucina-7/metabolismo , Modelos Moleculares , Simulação de Acoplamento Molecular , Domínios e Motivos de Interação entre Proteínas , Receptores de Interleucina-7/metabolismo , Humanos , Cinética , Ligação Proteica , Conformação ProteicaRESUMO
GSK3532795 (formerly BMS955176) is a second-generation maturation inhibitor (MI) that progressed through a Phase 2b study for treatment of HIV-1 infection. Resistance development to GSK3532795 was evaluated through in vitro methods and was correlated with information obtained in a Phase 2a proof-of-concept study in HIV-1 infected participants. Both low and high concentrations of GSK3532795 were used for selections in vitro, and reduced susceptibility to GSK3532795 mapped specifically to amino acids near the capsid/ spacer peptide 1 (SP1) junction, the cleavage of which is blocked by MIs. Two key substitutions, A364V or V362I, were selected, the latter requiring secondary substitutions to reduce susceptibility to GSK3532795. Three main types of secondary substitutions were observed, none of which reduced GSK3532795 susceptibility in isolation. The first type was in the capsid C-terminal domain and downstream SP1 region (including (Gag numbering) R286K, A326T, T332S/N, I333V and V370A/M). The second, was an R41G substitution in viral protease that occurred with V362I. The third was seen in the capsid N-terminal domain, within the cyclophilin A binding domain (V218A/M, H219Q and G221E). H219Q increased viral replication capacity and reduced susceptibility of poorly growing viruses. In the Phase 2a study, a subset of these substitutions was also observed at baseline and some were selected following GSK35323795 treatment in HIV-1-infected participants.
Assuntos
Fármacos Anti-HIV/uso terapêutico , Farmacorresistência Viral/genética , Infecções por HIV/tratamento farmacológico , Fármacos Anti-HIV/farmacologia , Proteínas do Capsídeo/genética , Genótipo , Protease de HIV/genética , HIV-1/genética , HIV-1/isolamento & purificação , HIV-1/fisiologia , Humanos , Mutação , Replicação Viral/efeitos dos fármacos , Produtos do Gene gag do Vírus da Imunodeficiência Humana/genéticaRESUMO
GSK3532795, formerly known as BMS-955176 (1), is a potent, orally active, second-generation HIV-1 maturation inhibitor (MI) that advanced through phase IIb clinical trials. The careful design, selection, and evaluation of substituents appended to the C-3 and C-17 positions of the natural product betulinic acid (3) was critical in attaining a molecule with the desired virological and pharmacokinetic profile. Herein, we highlight the key insights made in the discovery program and detail the evolution of the structure-activity relationships (SARs) that led to the design of the specific C-17 amine moiety in 1. These modifications ultimately enabled the discovery of 1 as a second-generation MI that combines broad coverage of polymorphic viruses (EC50 <15 nM toward a panel of common polymorphisms representative of 96.5% HIV-1 subtype B virus) with a favorable pharmacokinetic profile in preclinical species.
Assuntos
Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Crisenos/química , Morfolinas/química , Relação Estrutura-Atividade , Triterpenos/química , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Administração Oral , Animais , Fármacos Anti-HIV/farmacocinética , Ácido Benzoico/química , Disponibilidade Biológica , Técnicas de Química Sintética , Crisenos/farmacologia , Cães , Desenho de Fármacos , Estabilidade de Medicamentos , HIV-1/efeitos dos fármacos , HIV-1/genética , Humanos , Macaca fascicularis , Masculino , Camundongos Endogâmicos , Camundongos Knockout , Microssomos Hepáticos/efeitos dos fármacos , Morfolinas/farmacologia , Polimorfismo Genético , Ratos Sprague-Dawley , Triterpenos/farmacologiaRESUMO
In solving the P-gp and BCRP transporter-mediated efflux issue in a series of benzofuran-derived pan-genotypic palm site inhibitors of the hepatitis C virus NS5B replicase, it was found that close attention to physicochemical properties was essential. In these compounds, where both molecular weight (MW >579) and TPSA (>110 Å2) were high, attenuation of polar surface area together with weakening of hydrogen bond acceptor strength of the molecule provided a higher intrinsic membrane permeability and more desirable Caco-2 parameters, as demonstrated by trifluoroacetamide 11 and the benchmark N-ethylamino analog 12. In addition, the tendency of these inhibitors to form intramolecular hydrogen bonds potentially contributes favorably to the improved membrane permeability and absorption. The functional group minimization that resolved the efflux problem simultaneously maintained potent inhibitory activity toward a gt-2 HCV replicon due to a switching of the role of substituents in interacting with the Gln414 binding pocket, as observed in gt-2a NS5B/inhibitor complex cocrystal structures, thus increasing the efficiency of the optimization. Noteworthy, a novel intermolecular S=O···C=O n â π* type interaction between the ligand sulfonamide oxygen atom and the carbonyl moiety of the side chain of Gln414 was observed. The insights from these structure-property studies and crystallography information provided a direction for optimization in a campaign to identify second generation pan-genotypic NS5B inhibitors.
RESUMO
Higher-order structure (HOS) is a crucial determinant for the biological functions and quality attributes of protein therapeutics. Mass spectrometry (MS)-based protein footprinting approaches play an important role in elucidating the relationship between protein biophysical properties and structure. Here, we describe the use of a combined method including hydrogen-deuterium exchange (HDX), fast photochemical oxidation of proteins (FPOP), and site-specific carboxyl group footprinting to investigate the HOS of protein and protein complexes. The work focuses on implementing complementary solution-phase footprinting approaches that differ in time scale, specificity for protein residue side chains vs backbone as well as selectivity for different residue types to map integratively the epitope of human interleukin-6 receptor (IL-6R) for two adnectins with distinct affinities (Kd, Adnectin1 â¼ 6.2 pM vs Kd, Adnectin2 â¼ 46 nM). Furthermore, the study evaluates the resultant conformation/dynamic change of IL-6R. The suggested epitope, which is conserved for adnectin1 and adnectin2 binding, is a flexible loop that connects two ß-strands in the cytokine-binding domain (DII) of IL-6R. We also found that adnectin1, the more strongly binding ligand, induces structural perturbations on two unstructured loops that are distally located beyond the epitope. Those changes are either attenuated or not detected for the case of adnectin2 binding. In addition to providing credibility in epitope determination, utilization of those combined approaches reveals the structural effects that can differentiate protein therapeutics with apparently similar biophysical properties.
Assuntos
Mapeamento de Epitopos , Pegadas de Proteínas , Receptores de Interleucina-6/química , Medição da Troca de Deutério , Humanos , Espectrometria de Massas , Ligação Proteica , Conformação ProteicaRESUMO
The hepatitis C virus (HCV) NS5B replicase is a prime target for the development of direct-acting antiviral drugs for the treatment of chronic HCV infection. Inspired by the overlay of bound structures of three structurally distinct NS5B palm site allosteric inhibitors, the high-throughput screening hit anthranilic acid 4, the known benzofuran analogue 5, and the benzothiadiazine derivative 6, an optimization process utilizing the simple benzofuran template 7 as a starting point for a fragment growing approach was pursued. A delicate balance of molecular properties achieved via disciplined lipophilicity changes was essential to achieve both high affinity binding and a stringent targeted absorption, distribution, metabolism, and excretion profile. These efforts led to the discovery of BMS-929075 (37), which maintained ligand efficiency relative to early leads, demonstrated efficacy in a triple combination regimen in HCV replicon cells, and exhibited consistently high oral bioavailability and pharmacokinetic parameters across preclinical animal species. The human PK properties from the Phase I clinical studies of 37 were better than anticipated and suggest promising potential for QD administration.
Assuntos
Antivirais/farmacologia , Antivirais/farmacocinética , Benzofuranos/farmacologia , Benzofuranos/farmacocinética , Hepacivirus/efeitos dos fármacos , Hepatite C/tratamento farmacológico , Proteínas não Estruturais Virais/antagonistas & inibidores , Regulação Alostérica/efeitos dos fármacos , Sítio Alostérico/efeitos dos fármacos , Animais , Antivirais/química , Benzofuranos/química , Cães , Descoberta de Drogas , Haplorrinos , Hepatite C/virologia , Humanos , Masculino , Simulação de Acoplamento Molecular , Ratos , Ratos Sprague-Dawley , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/metabolismoRESUMO
Alkoxyanthranilic acid derivatives have been identified to inhibit HCV NS5B polymerase, binding in an allosteric site located at the convergence of the palm and thumb regions. Information from co-crystal structures guided the structural design strategy. Ultimately, two independent structural modifications led to a similar shift in binding mode that when combined led to a synergistic improvement in potency and the identification of inhibitors with sub-micromolar HCV NS5B binding potency.
Assuntos
Descoberta de Drogas , Inibidores Enzimáticos/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , ortoaminobenzoatos/farmacologia , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/metabolismo , ortoaminobenzoatos/síntese química , ortoaminobenzoatos/químicaRESUMO
The development of a series of novel 7-azabenzofurans exhibiting pan-genotype inhibition of HCV NS5B polymerase via binding to the primer grip site is presented. Many challenges, including poor oral bioavailability, high clearance, bioactivation, high human serum shift, and metabolic stability were encountered and overcome through SAR studies. This work culminated in the selection of BMS-986139 (43) as a preclinical candidate.
RESUMO
HIV-1 maturation inhibition (MI) has been clinically validated as an approach to the control of HIV-1 infection. However, identifying an MI with both broad polymorphic spectrum coverage and good oral exposure has been challenging. Herein, we describe the design, synthesis, and preclinical characterization of a potent, orally active, second generation HIV-1 MI, BMS-955176 (2), which is currently in Phase IIb clinical trials as part of a combination antiretroviral regimen.
RESUMO
A phenotypic high-throughput cell culture screen was performed to identify compounds that prevented proliferation of the human Papilloma virus type 16 (HPV-16) transformed cell line Ca Ski. A series of quinoxaline compounds exemplified by Compound 1 was identified. Testing against a panel of cell lines demonstrated that Compound 1 selectively inhibited replication of all HPV-16, HPV-18, and HPV-31 transformed cell lines tested with 50% Inhibitory Concentration (IC50) values of 2 to 8 µM relative to IC50 values of 28 to 73 µM in HPV-negative cell lines. Treatment with Compound 1 resulted in a cascade of multiple apoptotic events, including selective activation of effector caspases 3 and 7, fragmentation of cellular DNA, and PARP (poly(ADP-ribose) polymerase) cleavage in HPV-positive cells relative to HPV-negative cells. Unregulated proliferation of HPV transformed cells is dependent on the viral oncogenes, E6 and E7. Treatment with Compound 1 resulted in a decrease in HPV E7 protein in Ca Ski cells. However, the timing of this reduction relative to other effects of compound treatment suggests that this was a consequence, rather than a cause, of the apoptotic cascade. Likewise, compound treatment resulted in no obvious effects on the E6- and E7- mediated down regulation of p53 and Rb, or their downstream effectors, p21 or PCNA. Further investigation of apoptotic signals induced by Compound 1 revealed cleavage of Caspase-8 in HPV-positive cells as early as 2 hours post-treatment, suggesting the compound initiates apoptosis through the extrinsic, death receptor-mediated, pathway of cell death. These studies provide proof of concept that cells transformed by oncogenic Papillomaviruses can be selectively induced to undergo apoptosis by compound treatment.
Assuntos
Apoptose/efeitos dos fármacos , Transformação Celular Viral/efeitos dos fármacos , Papillomaviridae/efeitos dos fármacos , Infecções por Papillomavirus/patologia , Bibliotecas de Moléculas Pequenas/farmacologia , Neoplasias do Colo do Útero/patologia , Proteínas Reguladoras de Apoptose/metabolismo , Feminino , Humanos , Proteínas E7 de Papillomavirus/metabolismo , Infecções por Papillomavirus/tratamento farmacológico , Infecções por Papillomavirus/virologia , Proteína do Retinoblastoma/metabolismo , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/metabolismo , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/virologiaRESUMO
A series of C-3 phenyl- and heterocycle-substituted derivatives of C-3 deoxybetulinic acid and C-3 deoxybetulin was designed and synthesized as HIV-1 maturation inhibitors (MIs) and evaluated for their antiviral activity and cytotoxicity in cell culture. A 4-subsituted benzoic acid moiety was identified as an advantageous replacement for the 3'3'-dimethylsuccinate moiety present in previously disclosed MIs that illuminates new aspects of the topography of the pharmacophore. The new analogs exhibit excellent in vitro antiviral activity against wild-type (wt) virus and a lower serum shift when compared with the prototypical HIV-1 MI bevirimat (1, BVM), the first MI to be evaluated in clinical studies. Compound 9a exhibits comparable cell culture potency toward wt virus as 1 (WT EC50=16 nM for 9a compared to 10nM for 1). However, the potency of 9a is less affected by the presence of human serum, while the compound displays a similar pharmacokinetic profile in rats to 1. Hence 9a, the 4-benzoic acid derivative of deoxybetulinic acid, represents a new starting point from which to explore the design of a 2nd generation MI.
Assuntos
Fármacos Anti-HIV/farmacologia , HIV-1/efeitos dos fármacos , HIV-1/crescimento & desenvolvimento , Triterpenos/farmacologia , Animais , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/química , Células Cultivadas , Relação Dose-Resposta a Droga , Humanos , Testes de Sensibilidade Microbiana , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Microssomos Hepáticos/virologia , Estrutura Molecular , Ratos , Relação Estrutura-Atividade , Triterpenos/síntese química , Triterpenos/química , Replicação Viral/efeitos dos fármacosRESUMO
Calcitonin gene-related peptide (CGRP) is a potent neuropeptide implicated in the pathophysiology of migraine. In the course of seeking CGRP antagonists with improved oral bioavailability, metabolic stability, and pharmacokinetic properties, lower molecular weight, structurally simpler piperidine and piperazine analogs of BMS-694153 were prepared. Several were found to have nM binding affinity in vitro. The synthesis and SAR of these substituted piperidine and piperazine CGRP antagonists are discussed.
Assuntos
Peptídeo Relacionado com Gene de Calcitonina/antagonistas & inibidores , Indazóis/química , Piperazinas/química , Piperidinas/química , Quinazolinonas/química , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Linhagem Celular Tumoral , Permeabilidade da Membrana Celular/efeitos dos fármacos , Humanos , Indazóis/síntese química , Indazóis/farmacologia , Concentração Inibidora 50 , Piperazina , Quinazolinonas/síntese química , Quinazolinonas/farmacologia , Relação Estrutura-AtividadeRESUMO
The present studies represent the first published report of a dopamine D1 positive allosteric modulator (PAM). D1 receptors have been proposed as a therapeutic target for the treatment of cognitive deficits associated with schizophrenia. However, the clinical utility of orthosteric agonist compounds is limited by cardiovascular side effects, poor pharmacokinetics, lack of D1 selectivity, and an inverted dose response. A number of these challenges may be overcome by utilization of a selective D1 PAM. The current studies describe two chemically distinct D1 PAMs: Compound A [1-((rel-1S,3R,6R)-6-(benzo[d][1,3]dioxol-5-yl)bicyclo[4.1.0]heptan-3-yl)-4-(2-bromo-5-chlorobenzyl)piperazine] and Compound B [rel-(9R,10R,12S)-N-(2,6-dichloro-3-methylphenyl)-12-methyl-9,10-dihydro-9,10-ethanoanthracene-12-carboxamide]. Compound A shows pure PAM activity, with an EC50 of 230 nM and agonist activity at the D2 receptor in D2-expressing human embryonic kidney cells. Compound B shows superior potency (EC50 of 43 nM) and selectivity for D1 versus D2 dopamine receptors. Unlike Compound A, Compound B is selective for human and nonhuman primate D1 receptors, but lacks activity at the rodent (rat and mouse) D1 receptors. Using molecular biology techniques, a single amino acid was identified at position 130, which mediates the species selectivity of Compound B. These data represent the first described D1-selective PAMs and define critical amino acids that regulate species selectivity.
Assuntos
Regulação Alostérica/efeitos dos fármacos , Receptores de Dopamina D1/agonistas , Receptores de Dopamina D2/agonistas , Animais , Células CHO , Linhagem Celular , Células Cultivadas , Cricetulus , Células HEK293 , Humanos , Camundongos , Ratos , Esquizofrenia/tratamento farmacológicoRESUMO
Electron deficient, bivalent sulfur atoms have two areas of positive electrostatic potential, a consequence of the low-lying σ* orbitals of the C-S bond that are available for interaction with electron donors including oxygen and nitrogen atoms and, possibly, π-systems. Intramolecular interactions are by far the most common manifestation of this effect, which offers a means of modulating the conformational preferences of a molecule. Although a well-documented phenomenon, a priori applications in drug design are relatively sparse and this interaction, which is often isosteric with an intramolecular hydrogen-bonding interaction, appears to be underappreciated by the medicinal chemistry community. In this Perspective, we discuss the theoretical basis for sulfur σ* orbital interactions and illustrate their importance in the context of drug design and organic synthesis. The role of sulfur interactions in protein structure and function is discussed and although relatively rare, intermolecular interactions between ligand C-S σ* orbitals and proteins are illustrated.
Assuntos
Desenho de Fármacos , Enxofre/química , Enxofre/metabolismo , Humanos , Ligação de Hidrogênio , Modelos Moleculares , Proteínas/química , Proteínas/metabolismoRESUMO
Described herein are structure-activity relationship studies that resulted in the optimization of the activity of members of a class of cyclopropyl-fused indolobenzazepine HCV NS5B polymerase inhibitors. Subsequent iterations of analogue design and syntheses successfully addressed off-target activities, most notably human pregnane X receptor (hPXR) transactivation, and led to significant improvements in the physicochemical properties of lead compounds. Those analogues exhibiting improved solubility and membrane permeability were shown to have notably enhanced pharmacokinetic profiles. Additionally, a series of alkyl bridged piperazine carboxamides was identified as being of particular interest, and from which the compound BMS-791325 (2) was found to have distinguishing antiviral, safety, and pharmacokinetic properties that resulted in its selection for clinical evaluation.