RESUMEN
Synthesis of analogs containing more rigid bicyclic piperidine replacements for the 4-benzyloxycarbonyl-(ethyl)amino-piperidine moiety of the CCR5 antagonist structure, 1, is described. Although similar binding affinity to the lead was achieved with some analogs they were overall less potent anti-HIV agents suggesting that other features besides CCR5 binding are required for good anti-viral activity.
Asunto(s)
Fármacos Anti-VIH/síntesis química , Antagonistas de los Receptores CCR5 , Sulfonas/síntesis química , Fármacos Anti-VIH/farmacología , Butanos/síntesis química , Butanos/farmacología , Relación Dosis-Respuesta a Droga , Concentración 50 Inhibidora , Piperidinas/síntesis química , Piperidinas/farmacología , Relación Estructura-Actividad , Sulfonas/farmacología , Virus/efectos de los fármacosRESUMEN
Cellular proliferation of HIV-1 requires the cooperative assistance of both the CCR5 and CD4 receptors. Our medicinal chemistry efforts in this area have resulted in the identification of N-alkyl piperidine sulfones as CCR5 antagonists. These compounds display potent binding and show antiviral properties in HIV-1 spread cell-based assays.
Asunto(s)
Fármacos Anti-VIH/síntesis química , Antagonistas de los Receptores CCR5 , Sulfonas/síntesis química , Fármacos Anti-VIH/farmacología , Sitios de Unión , Antígenos CD4/metabolismo , Línea Celular , Diseño de Fármacos , Humanos , Concentración 50 Inhibidora , Piperidinas/química , Receptores CCR5/metabolismo , Estereoisomerismo , Relación Estructura-Actividad , Sulfonas/farmacologíaRESUMEN
A fluorescence-based, multiplexed, antibody-binding and mapping assay was developed to characterize antibody responses in HIV-1-infected individuals to the ectodomain of the HIV-1 gp41 envelope glycoprotein. The antigen panel included intact recombinant gp41, the fusion peptide region, the polar region, the N-heptad region, the C-heptad region as well as overlapping epitopes in the 2F5 and 4E10 monoclonal antibody-binding regions. The panel included both native and constrained peptides specifically designed to mimic putative gp41 prefusion and fusion intermediates. The results of these analyses revealed a broad pattern of immune responses against the test antigens, suggesting that none of these gp41 regions are immunologically silent. The HIV-1-positive sera were also evaluated using infectivity inhibition assays. No correlation was evident between the breadth or magnitude of specific anti-gp41 reactivities and virus neutralization potency. These evaluations demonstrated the substantial potential of the multiplexed antibody binding and mapping assay for rapid and sensitive analysis of complex antibody responses.
Asunto(s)
Mapeo Epitopo , Técnica del Anticuerpo Fluorescente/métodos , Anticuerpos Anti-VIH/análisis , Proteína gp41 de Envoltorio del VIH/inmunología , VIH-1/inmunología , Secuencia de Aminoácidos , Animales , Ensayo de Inmunoadsorción Enzimática , Mapeo Epitopo/métodos , Citometría de Flujo/métodos , Proteína gp41 de Envoltorio del VIH/química , Infecciones por VIH/sangre , Infecciones por VIH/inmunología , Humanos , Datos de Secuencia Molecular , Pruebas de Neutralización , Conformación Proteica , Sensibilidad y EspecificidadRESUMEN
Replacement of the flexible connecting chains between the piperidine moiety and an aromatic group in previous CCR5 antagonists with heterocycles, such as pyrazole and isoxazole, provided potent CCR5 antagonists with excellent anti-HIV-1 activity in vitro. SAR studies revealed optimal placement of an unsubstituted nitrogen atom in the heterocycle to be meta to the bond connected to the 4-position of piperidine. Truncation of a benzyl group to a phenyl group afforded compounds with dramatically improved oral bioavailability, albeit with reduced activity.
Asunto(s)
Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/farmacocinética , Antagonistas de los Receptores CCR5 , Piperidinas/síntesis química , Piperidinas/farmacocinética , Animales , Fármacos Anti-VIH/química , División Celular/efectos de los fármacos , Células HeLa , Humanos , Estructura Molecular , Piperidinas/química , Pirazoles/química , Pirazoles/farmacocinética , Ratas , Relación Estructura-ActividadRESUMEN
Modifications of the alkyl acetic acid portion and the phenyl on pyrrolidine in our lead pyrazole compound 1 afforded the isopropyl compound 9. This compound is a potent CCR5 antagonist showing good in vitro antiviral activity against HIV-1, an excellent selectivity profile, and good oral bioavailability in three animal species. During this investigation, a new method for the preparation of alpha-(pyrrolidin-1-yl)-alpha,alpha-dialkyl acetic acid from a pyrrolidine and alpha-bromo-alpha,alpha-dialkyl acetic acid using silver triflate was discovered. This allowed us to prepare compounds such as 24 and 25 for the first time. A novel Pd-mediated N-dealkylation of alpha-(pyrrolidin-1-yl)acetic acid was also uncovered.
Asunto(s)
Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/farmacocinética , Antagonistas de los Receptores CCR5 , Piperidinas/síntesis química , Piperidinas/farmacocinética , Acetatos/química , Acetatos/farmacocinética , Administración Oral , Animales , Fármacos Anti-VIH/química , Disponibilidad Biológica , Perros , Células HeLa , Humanos , Macaca mulatta , Estructura Molecular , Monocitos/efectos de los fármacos , Piperidinas/química , Pirazoles/química , Pirazoles/farmacocinética , Ratas , Relación Estructura-ActividadRESUMEN
Extensive SAR studies in our benzylpyrazole series of CCR5 antagonists have shown that both lipophilic and hydrophilic substituents on the phenyl of the benzyl group increase antiviral potency. However, improvements in pharmacokinetic profiles were generally only observed with more lipophilic substitutions. 4-Biphenyl (51) performed the best in this regard. Highly lipophilic substituents impart undesirable ion channel activity to these CCR5 antagonists. Alkoxy substituents provide a good balance of antiviral activity, pharmacokinetic parameters, and selectivity. Compounds 42b and 42d, containing a 3,4-dimethoxy substituent, are considered the most promising improvements over parent compounds 9. They demonstrate improved antiviral activity while retaining good pharmacokinetic profile and selectivity.
Asunto(s)
Fármacos Anti-VIH/química , Fármacos Anti-VIH/farmacocinética , Antagonistas de los Receptores CCR5 , Piperidinas/química , Piperidinas/farmacocinética , Pirazoles/química , Animales , Fármacos Anti-VIH/síntesis química , Disponibilidad Biológica , Perros , Células HeLa , Humanos , Estructura Molecular , Monocitos/efectos de los fármacos , Piperidinas/síntesis química , Pirazoles/farmacocinética , Ratas , Relación Estructura-ActividadRESUMEN
[reaction: see text] A novel approach to alpha,alpha-disubstituted-beta-amino acids (beta(2,2)-amino acids) was employed in the synthesis of a series of 3-(pyrrolidin-1-yl)propionic acids possessing high affinity for the CCR5 receptor and potent anti-HIV activity. The rat pharmacokinetics for these new analogues featured higher bioavailabilities and lower rates of clearance as compared to cyclopentane 1.
Asunto(s)
Fármacos Anti-VIH/farmacología , Antagonistas de los Receptores CCR5 , Propionatos/farmacología , Pirrolidinas/farmacología , Fármacos Anti-VIH/farmacocinética , Disponibilidad Biológica , Propionatos/farmacocinética , Pirrolidinas/farmacocinéticaRESUMEN
A new class of 4-(aminoheterocycle)piperidine derived 1,3,4 trisubstituted pyrrolidine CCR5 antagonists is reported. Compound 4a is shown to have good binding affinity (1.8 nM) and antiviral activity in PBMC's (IC(95)=50 nM). Compound 4a also has improved PK properties relative to 1.
Asunto(s)
Antagonistas de los Receptores CCR5 , Piperidinas/síntesis química , Piperidinas/farmacología , Pirrolidinas/síntesis química , Pirrolidinas/farmacología , Animales , Fármacos Anti-VIH/síntesis química , Células CHO , Quimiocina CCL4 , Cricetinae , Semivida , Células HeLa , Humanos , Enlace de Hidrógeno , Proteínas Inflamatorias de Macrófagos/metabolismo , Piperidinas/farmacocinética , Pirrolidinas/farmacocinética , RatasRESUMEN
The 4-(3-phenylprop-1-yl)piperidine moiety of the 1,3,4-trisubstituted pyrrolidine CCR5 antagonist 1 was modified with electron deficient aromatics as well as replacement of the benzylic methylene with sulfones, gem-difluoromethylenes and alcohols in an effort to balance the antiviral potency with reasonable pharmacokinetics.
Asunto(s)
Fármacos Anti-VIH/síntesis química , Antagonistas de los Receptores CCR5 , Pirrolidinas/farmacocinética , Animales , Fármacos Anti-VIH/farmacocinética , Fármacos Anti-VIH/farmacología , Perros , Semivida , Humanos , Leucocitos Mononucleares , Macaca mulatta , Tasa de Depuración Metabólica , Piperidinas/química , Pirrolidinas/síntesis química , Pirrolidinas/farmacología , Ensayo de Unión Radioligante , Ratas , Relación Estructura-Actividad , Células Tumorales CultivadasRESUMEN
Human immunodeficiency virus-type 1 (HIV-1) reverse transcriptase (RT) coordinates DNA polymerization and ribonuclease H (RNase H) activities using two discrete active sites embedded within a single heterodimeric polyprotein. We have identified a novel thiophene diketo acid, 4-[5-(benzoylamino)thien-2-yl]-2,4-dioxobutanoic acid, that selectively inhibits polymerase-independent RNase H cleavage (IC(50) = 3.2 microm) but has no effect on DNA polymerization (IC(50) > 50 microm). The activity profile of the diketo acid is shown to be distinct from previously described compounds, including the polymerase inhibitor foscarnet and the putative RNase H inhibitor 4-chlorophenylhydrazone. Both foscarnet and the hydrazone inhibit RNase H cleavage and DNA polymerization activities of RT, yet neither inhibits the RNase H activity of RT containing a mutation in the polymerase active site (D185N) or an isolated HIV-1 RNase H domain chimera containing the alpha-C helix from Escherichia coli RNase HI, suggesting these compounds affect RNase H indirectly. In contrast, the diketo acid inhibits the RNase H activity of the isolated RNase H domain as well as full-length RT, and inhibition is not affected by the polymerase active site mutation. In isothermal titration calorimetry studies using the isolated RNase H domain, binding of the diketo acid is independent of nucleic acid but strictly requires Mn(2+) implying a direct interaction between the inhibitor and the RNase H active site. These studies demonstrate that inhibition of HIV-1 RNase H may occur by either direct or indirect mechanisms, and they provide a framework for identifying novel agents such as 4-[5-(benzoylamino)thien- 2-yl]-2,4-dioxobutanoic acid that specifically targets RNase H.
Asunto(s)
Butiratos/farmacología , Inhibidores Enzimáticos/farmacología , VIH-1/enzimología , Ribonucleasa H/antagonistas & inhibidores , Tiofenos/farmacología , Butiratos/síntesis química , Inhibidores Enzimáticos/síntesis química , Foscarnet/farmacología , Cinética , ADN Polimerasa Dirigida por ARN/metabolismo , Inhibidores de la Transcriptasa Inversa/farmacología , Ribonucleasa H/química , Ribonucleasa H/genética , Relación Estructura-Actividad , Especificidad por Sustrato , Tiofenos/síntesis químicaRESUMEN
The synthetic peptide DP178, derived from the carboxyl-terminal heptad repeat region of human immunodeficiency virus type 1 GP41 protein is a potent inhibitor of viral-mediated fusion and contains the sequence ELDKWA, which constitutes the recognition epitope for the broadly neutralizing human monoclonal antibody 2F5. Efforts at eliciting a 2F5-like immune response by immunization with peptides or fusion proteins containing this sequence have not met with success, possibly because of incorrect structural presentation of the epitope. Although the structure of the carboxyl-terminal heptad repeat on the virion is not known, several recent reports have suggested a propensity for alpha-helical conformation. We have examined DP178 in the context of a model for optimized alpha-helices and show that the native sequence conforms poorly to the model. Solution conformation of DP178 was studied by circular dichroism and NMR spectroscopy and found to be predominantly random, consistent with previous reports. NMR mapping was used to show that the low percentage of alpha-helix present was localized to residues Glu(662) through Asn(671), a region encompassing the 2F5 epitope. Using NH(2)-terminal extensions derived from either GP41 or the yeast GCN4 leucine zipper dimerization domain, we designed peptide analogs in which the average helicity is significantly increased compared with DP178 and show that these peptides exhibit both a modest increase in affinity for 2F5 using a novel competitive solution-based binding assay and an increased ability to inhibit viral entry in a single-cycle infectivity model. Selected peptides were conjugated to carrier protein and used for guinea pig immunizations. High peptide-specific titers were achieved using these immunogens, but the resulting sera were incapable of viral neutralization. We discuss these findings in terms of structural and immunological considerations as to the utility of a 2F5-like response.
Asunto(s)
Vacunas contra el SIDA/inmunología , Fármacos Anti-VIH/inmunología , Anticuerpos Monoclonales/inmunología , Proteína gp41 de Envoltorio del VIH/inmunología , Pruebas de Neutralización , Fragmentos de Péptidos/inmunología , Vacunas contra el SIDA/química , Secuencia de Aminoácidos , Fármacos Anti-VIH/química , Dicroismo Circular , Enfuvirtida , Proteína gp41 de Envoltorio del VIH/química , Humanos , Técnicas In Vitro , Espectroscopía de Resonancia Magnética , Datos de Secuencia Molecular , Fragmentos de Péptidos/químicaRESUMEN
Incorporation of acidic functional groups into a lead CCR5 antagonist identified from a targeted combinatorial library resulted in compounds with enhanced anti-HIV-1 activity and attenuated L-type calcium channel affinity.
Asunto(s)
Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/farmacología , Antagonistas de los Receptores CCR5 , VIH-1/efectos de los fármacos , Animales , Fármacos Anti-VIH/farmacocinética , Células CHO , Canales de Calcio Tipo L/efectos de los fármacos , Fenómenos Químicos , Química Física , Quimiocina CCL4 , Cricetinae , Semivida , Células HeLa , Humanos , Proteínas Inflamatorias de Macrófagos/antagonistas & inhibidores , Ratas , Receptores CCR5/química , Relación Estructura-ActividadRESUMEN
A series of alpha-(pyrrolidin-1-yl)acetic acids is presented as selective and potent antivirals against HIV. Several of the pyrrolidine zwitterions demonstrated reasonable in vitro properties, enhanced antiviral activities and improved pharmacokinetic profiles over pyrrolidine 1.
Asunto(s)
Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/farmacología , Antagonistas de los Receptores CCR5 , VIH-1/efectos de los fármacos , Pirrolidinas/síntesis química , Pirrolidinas/farmacología , Animales , Fármacos Anti-VIH/farmacocinética , Células CHO , Permeabilidad de la Membrana Celular , Fenómenos Químicos , Química Física , Quimiocina CCL4 , Cricetinae , Células HeLa , Humanos , Indicadores y Reactivos , Proteínas Inflamatorias de Macrófagos/antagonistas & inhibidores , Pirrolidinas/farmacocinética , Ratas , Relación Estructura-ActividadRESUMEN
Tat is a small HIV protein essential for both viral replication and the progression of HIV disease. In our efforts to discover Tat inhibitors from natural product screening of microbial fermentation extracts, we discovered durhamycin A (1) as a potent inhibitor (IC(50) = 4.8 nM) of Tat transactivation. Detailed NMR and MS/MS studies were utilized to elucidate the structure of 1 as a new member of the aureolic acid family of antibiotics. It consists of tetrasaccharide and disaccharide moieties attached to the aglycone, which is hitherto unknown in the aureolic acid family. Three other novel analogues, durhamycin B (2), compound (3), and the aglycone (4), were also discovered or chemically prepared that were less potent than durhamycin A.
Asunto(s)
Fármacos Anti-VIH/farmacología , Productos del Gen tat/antagonistas & inhibidores , Productos del Gen tat/fisiología , VIH-1/fisiología , Plicamicina/análogos & derivados , Costa Rica , Diseño de Fármacos , Regulación Viral de la Expresión Génica , Productos del Gen tat/metabolismo , Hidrólisis , Concentración 50 Inhibidora , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Estructura Molecular , Plicamicina/farmacología , Unión Proteica/efectos de los fármacos , Relación Estructura-Actividad , Especificidad por Sustrato , Productos del Gen tat del Virus de la Inmunodeficiencia HumanaRESUMEN
Human immunodeficiency virus (HIV) entry into a host cell requires the fusion of virus and cellular membranes that is driven by interaction of the viral envelope glycoproteins gp120 and gp41 (gp120/gp41) with CD4 and a coreceptor, typically either CXCR4 or CCR5. The stoichiometry of gp120/gp41:CD4:CCR5 necessary to initiate membrane fusion is not known. To allow an examination of early events in gp120/gp41-driven membrane fusion, we developed a novel real-time cell-cell fusion assay. Using this assay to study fusion kinetics, we found that altering the cell surface density of gp120/gp41 affected the maximal extent of fusion without dramatically altering fusion kinetics. Collectively, these observations are consistent with the view that gp120/gp41-driven membrane fusion requires the formation of a threshold number of fusion-active intercellular gp120/gp41:CD4:CCR5 complexes. Furthermore, the probability of reaching this threshold is governed, in part, by the surface density of gp120/gp41.
Asunto(s)
Proteína gp120 de Envoltorio del VIH/metabolismo , Proteína gp41 de Envoltorio del VIH/metabolismo , VIH-1/metabolismo , Fusión de Membrana , Proteínas Virales de Fusión/metabolismo , Línea Celular , Técnica del Anticuerpo Fluorescente , Células HeLa , Humanos , Factores de Tiempo , Replicación ViralRESUMEN
A series of CCR5 antagonists containing bicyclic isoxazolidines was generated through a nitrone mediated cycloaddition with olefins bearing the preferred pharmacophores previously described. Potent antagonists (3 and 16) were generated with enhanced affinity for the CCR5 receptor while maintaining antiviral activity against HIV.