RESUMEN
Use of the oxadiazolone acid isostere in triiodothyronine analogs yielded potent and selective agonists for the thyroid hormone receptor ß. Selected examples showed good in-vivo efficacy in a rat hypercholesterolemic model. One compound was further profiled in a diet-induced mouse model of nonalcoholic steatohepatitis (NASH) and showed robust target engagement and significant histological improvements in both liver steatosis and fibrosis.
Asunto(s)
Oxadiazoles/farmacología , Receptores beta de Hormona Tiroidea/agonistas , Animales , Relación Dosis-Respuesta a Droga , Masculino , Ratones , Ratones Endogámicos C57BL , Estructura Molecular , Oxadiazoles/síntesis química , Oxadiazoles/química , Ratas , Ratas Sprague-Dawley , Relación Estructura-ActividadRESUMEN
Delivery of pharmacologically active nucleoside triphosphate analogs to sites of viral infection is challenging. In prior work we identified a 2'-C-methyl-1'-cyano-7-deaza-adenosine C-nucleotide analog with desirable selectivity and potency for the treatment of hepatitis C virus (HCV) infection. However, the prodrug selected for clinical development, GS-6620, required a high dose for meaningful efficacy and had unacceptable variability due to poor oral absorption as a result of suboptimal solubility, intestinal metabolism, and efflux transport. While obtaining clinical proof of concept for the nucleotide analog, a more effective prodrug strategy would be necessary for clinical utility. Here, we report an alternative prodrug of the same nucleoside analog identified to address liabilities of GS-6620. A phosphoramidate prodrug containing the nonproteinogenic amino acid methylalanine, an isopropyl ester and phenol in the (S) conformation at phosphorous, GS2, was found to have improved solubility, intestinal stability, and hepatic activation. GS2 is a more selective substrate for hepatically expressed carboxyl esterase 1 (CES1) and is resistant to hydrolysis by more widely expressed hydrolases, including cathepsin A (CatA) and CES2. Unlike GS-6620, GS2 was not cleaved by intestinally expressed CES2 and, as a result, was stable in intestinal extracts. Levels of liver triphosphate following oral administration of GS2 in animals were higher than those of GS-6620, even when administered under optimal conditions for GS-6620 absorption. Combined, these properties suggest that GS2 will have better oral absorption in the clinic when administered in a solid dosage form and the potential to extend the clinical proof of concept obtained with GS-6620.
Asunto(s)
Antivirales/uso terapéutico , Hepacivirus/patogenicidad , Nucleótidos/uso terapéutico , Profármacos/uso terapéutico , Triazinas/uso terapéutico , Adenosina/análogos & derivados , Administración Oral , Alanina , Animales , Antivirales/administración & dosificación , Antivirales/farmacocinética , Células CACO-2 , Células Cultivadas , Perros , Hepacivirus/efectos de los fármacos , Hepatitis C/virología , Humanos , Masculino , Nucleótidos/administración & dosificación , Nucleótidos/farmacocinética , Profármacos/administración & dosificación , Profármacos/farmacocinética , Ratas , Triazinas/administración & dosificación , Triazinas/farmacocinética , Replicación Viral/efectos de los fármacosRESUMEN
Influenza polymerase is a heterotrimer composed of polymerase acidic protein A (PA) and basic proteins 1 (PB1) and 2 (PB2). The endonuclease active site, located in the PA subunit, cleaves host mRNA to prime viral mRNA transcription, and is essential for viral replication. To date, the human influenza A endonuclease activity has only been studied on the truncated active-site containing N-terminal domain of PA (PAN) or full-length PA in the absence of PB1 or PB2. In this study, we characterized the endonuclease activity of recombinant proteins of influenza A/PR8 containing full length PA, PA/PB1 dimer, and PA/PB1/PB2 trimer, observing 8.3-, 265-, and 142-fold higher activity than PAN, respectively. Using the PA/PB1/PB2 trimer, we developed a robust endonuclease assay with a synthetic fluorogenic RNA substrate. The observed Km (150 ± 11 nM) and kcat [(1.4 ± 0.2) x 10-3s-1] values were consistent with previous reports using virion-derived replication complex. Two known influenza endonuclease phenylbutanoic acid inhibitors showed IC50 values of 10-20 nM, demonstrating the utility of this system for future high throughput screening.
Asunto(s)
Endonucleasas/antagonistas & inhibidores , Endonucleasas/metabolismo , Inhibidores Enzimáticos/farmacología , Virus de la Influenza A/efectos de los fármacos , Virus de la Influenza A/enzimología , ARN Polimerasa Dependiente del ARN/metabolismo , Endonucleasas/química , Activación Enzimática/efectos de los fármacos , Concentración 50 Inhibidora , ARN Mensajero/metabolismo , ARN Polimerasa Dependiente del ARN/antagonistas & inhibidores , ARN Polimerasa Dependiente del ARN/química , Proteínas Virales/antagonistas & inhibidores , Proteínas Virales/química , Proteínas Virales/metabolismoRESUMEN
A series of 2'-fluorinated C-nucleosides were prepared and tested for anti-HCV activity. Among them, the triphosphate of 2'-fluoro-2'-C-methyl adenosine C-nucleoside (15) was a potent and selective inhibitor of the NS5B polymerase and maintained activity against the S282T resistance mutant. A number of phosphoramidate prodrugs were then prepared and evaluated leading to the identification of the 1-aminocyclobutane-1-carboxylic acid isopropyl ester variant (53) with favorable pharmacokinetic properties including efficient liver delivery in animals.
Asunto(s)
Antivirales/química , Antivirales/farmacología , Hepacivirus/efectos de los fármacos , Nucleósidos/química , Nucleósidos/farmacología , Proteínas no Estructurales Virales/antagonistas & inhibidores , Amidas/química , Amidas/farmacocinética , Amidas/farmacología , Animales , Antivirales/farmacocinética , Células CACO-2 , Línea Celular , Cricetinae , Descubrimiento de Drogas , Farmacorresistencia Viral , Halogenación , Hepacivirus/genética , Hepacivirus/fisiología , Hepatitis C/tratamiento farmacológico , Humanos , Metilación , Simulación del Acoplamiento Molecular , Nucleósidos/farmacocinética , Ácidos Fosfóricos/química , Ácidos Fosfóricos/farmacocinética , Ácidos Fosfóricos/farmacología , Mutación Puntual , Profármacos/química , Profármacos/farmacocinética , Profármacos/farmacología , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
Ribose modified 1'-C-cyano pyrimidine nucleosides were synthesized. A silver triflate mediated Vorbrüggen reaction was used to generate the nucleoside scaffold and follow-up chemistry provided specific ribose modified analogs. Nucleosides and phosphoramidate prodrugs were tested for their anti-HCV activity.
Asunto(s)
ARN Polimerasas Dirigidas por ADN/antagonistas & inhibidores , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Hepacivirus/enzimología , Nucleósidos de Pirimidina/síntesis química , Nucleósidos de Pirimidina/farmacología , Técnicas de Química Sintética , Inhibidores Enzimáticos/química , Nucleósidos de Pirimidina/químicaRESUMEN
Ledipasvir, a direct acting antiviral agent (DAA) targeting the Hepatitis C Virus NS5A protein, exhibits picomolar activity in replicon cells. While its mechanism of action is unclear, mutations that confer resistance to ledipasvir in HCV replicon cells are located in NS5A, suggesting that NS5A is the direct target of ledipasvir. To date co-precipitation and cross-linking experiments in replicon or NS5A transfected cells have not conclusively shown a direct, specific interaction between NS5A and ledipasvir. Using recombinant, full length NS5A, we show that ledipasvir binds directly, with high affinity and specificity, to NS5A. Ledipasvir binding to recombinant NS5A is saturable with a dissociation constant in the low nanomolar range. A mutant form of NS5A (Y93H) that confers resistance to ledipasvir shows diminished binding to ledipasvir. The current study shows that ledipasvir inhibits NS5A through direct binding and that resistance to ledipasvir is the result of a reduction in binding affinity to NS5A mutants.
Asunto(s)
Antivirales/farmacología , Bencimidazoles/farmacología , Farmacorresistencia Viral/genética , Fluorenos/farmacología , Hepacivirus/efectos de los fármacos , Mutación , Proteínas no Estructurales Virales/genética , Secuencia de Aminoácidos , Antivirales/química , Bencimidazoles/química , Línea Celular Tumoral , Fluorenos/química , Hepacivirus/genética , Hepacivirus/metabolismo , Hepatocitos/efectos de los fármacos , Hepatocitos/patología , Hepatocitos/virología , Humanos , Cinética , Datos de Secuencia Molecular , Unión Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Replicón , Proteínas no Estructurales Virales/antagonistas & inhibidores , Proteínas no Estructurales Virales/metabolismo , Replicación ViralRESUMEN
The first synthesis of 1'-C-CN, 2'-F, 2'-C-Me pyrimidines is described. Anti-HCV activity was assessed and compared to the 1'-C-CN, 2'-C-Me as well as the 2'-F, 2'-C-Me pyrimidines. A phosphoramidate prodrug of the cytidine derivative showed activity in the low micromolar range against HCV replicons.
Asunto(s)
Antivirales/química , Antivirales/farmacología , Hepacivirus/efectos de los fármacos , Nucleósidos de Pirimidina/química , Nucleósidos de Pirimidina/farmacología , Amidas/química , Amidas/farmacología , Línea Celular , Halogenación , Hepacivirus/enzimología , Hepatitis C/tratamiento farmacológico , Hepatitis C/virología , Humanos , Metilación , Ácidos Fosfóricos/química , Ácidos Fosfóricos/farmacología , Profármacos/química , Profármacos/farmacología , ARN Polimerasa Dependiente del ARN/antagonistas & inhibidores , Replicón/efectos de los fármacosRESUMEN
The first synthesis of 1'-cyano-2'-C-methyl pyrimidine nucleosides is described. Anti-HCV activity of these nucleosides and their nucleotide phosphoramidate prodrugs was assessed and compared to the 1'-unsubstituted counterparts and to the related 1'-cyano-2'-C-methyl C-nucleoside parent of GS-6620.
Asunto(s)
Antivirales/farmacología , Inhibidores Enzimáticos/farmacología , Hepacivirus/efectos de los fármacos , Hepacivirus/enzimología , Nucleósidos/farmacología , Nucleósidos de Pirimidina/farmacología , ARN Polimerasa Dependiente del ARN/antagonistas & inhibidores , Proteínas no Estructurales Virales/antagonistas & inhibidores , Antivirales/síntesis química , Antivirales/química , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Pruebas de Sensibilidad Microbiana , Conformación Molecular , Nucleósidos/síntesis química , Nucleósidos/química , Nucleósidos de Pirimidina/síntesis química , Nucleósidos de Pirimidina/química , ARN Polimerasa Dependiente del ARN/metabolismo , Relación Estructura-Actividad , Proteínas no Estructurales Virales/metabolismoRESUMEN
A sulfonamide replacement of the P2-P3 amide bond in the context of macrocyclic HCV NS3 protease inhibitors was investigated. These analogs displayed good inhibitory potency in the absence of any P3 capping group. The synthesis and preliminary SAR are described.
Asunto(s)
Hepacivirus/efectos de los fármacos , Sulfonamidas/química , Proteínas no Estructurales Virales/antagonistas & inhibidores , Activación Enzimática/efectos de los fármacos , Humanos , Concentración 50 Inhibidora , Estructura Molecular , Inhibidores de Proteasas/química , Inhibidores de Proteasas/farmacología , Relación Estructura-Actividad , Sulfonamidas/farmacologíaRESUMEN
A new class of highly potent NS5A inhibitors with an unsymmetric benzimidazole-difluorofluorene-imidazole core and distal [2.2.1]azabicyclic ring system was discovered. Optimization of antiviral potency and pharmacokinetics led to the identification of 39 (ledipasvir, GS-5885). Compound 39 (GT1a replicon EC50 = 31 pM) has an extended plasma half-life of 37-45 h in healthy volunteers and produces a rapid >3 log viral load reduction in monotherapy at oral doses of 3 mg or greater with once-daily dosing in genotype 1a HCV-infected patients. 39 has been shown to be safe and efficacious, with SVR12 rates up to 100% when used in combination with direct-acting antivirals having complementary mechanisms.
Asunto(s)
Antivirales/uso terapéutico , Bencimidazoles/uso terapéutico , Fluorenos/uso terapéutico , Hepatitis C/tratamiento farmacológico , Proteínas no Estructurales Virales/antagonistas & inhibidores , Administración Oral , Animales , Antivirales/administración & dosificación , Antivirales/farmacocinética , Secuencia de Bases , Bencimidazoles/farmacocinética , Bencimidazoles/farmacología , Cartilla de ADN , Método Doble Ciego , Fluorenos/farmacocinética , Fluorenos/farmacología , Semivida , Humanos , Macaca fascicularis , Masculino , Placebos , Ratas , Ratas Sprague-Dawley , Relación Estructura-ActividadRESUMEN
HIV-1 RNase H breaks down the intermediate RNA-DNA hybrids during reverse transcription, requiring two divalent metal ions for activity. Pyrimidinol carboxylic acid and N-hydroxy quinazolinedione inhibitors were designed to coordinate the two metal ions in the active site of RNase H. High-resolution (1.4 Å to 2.1 Å) crystal structures were determined with the isolated RNase H domain and reverse transcriptase (RT), which permit accurate assessment of the metal and water environment at the active site. The geometry of the metal coordination suggests that the inhibitors mimic a substrate state prior to phosphodiester catalysis. Surface plasmon resonance studies confirm metal-dependent binding to RNase H and demonstrate that the inhibitors do not bind at the polymerase active site of RT. Additional evaluation of the RNase H site reveals an open protein surface with few additional interactions to optimize active-site inhibitors.
Asunto(s)
Fármacos Anti-VIH/farmacología , VIH-1/efectos de los fármacos , Pirimidinas/farmacología , Quinazolinonas/farmacología , Ribonucleasa H/antagonistas & inhibidores , Secuencia de Aminoácidos , Cristalización , Transcriptasa Inversa del VIH/antagonistas & inhibidores , Transcriptasa Inversa del VIH/química , VIH-1/enzimología , Conformación Molecular , Datos de Secuencia Molecular , Pirimidinas/química , Quinazolinonas/química , Ribonucleasa H/química , Relación Estructura-ActividadRESUMEN
Pyrimidinol carboxylic acids were designed as inhibitors of HIV-1 RNase H function. These molecules can coordinate to two divalent metal ions in the RNase H active site. Inhibition of enzymatic activity was measured in a biochemical assay, but no antiviral effect was observed. Binding was demonstrated via a solid state structure of the isolated p15-Ec domain of HIV-1 RT showing inhibitor and two Mn(II) ions bound to the RNase H active site.
Asunto(s)
Transcriptasa Inversa del VIH/antagonistas & inhibidores , Pirimidinas/farmacología , Ribonucleasa H/antagonistas & inhibidores , Ácidos Carboxílicos , Dominio Catalítico , Diseño de Fármacos , Humanos , Unión Proteica , Pirimidinas/químicaRESUMEN
A series of 3,4,5-trisubstituted 1,2,4-4H triazole derivatives was synthesized and investigated for HIV-1 reverse transcriptase inhibition. An X-ray structure with HIV-1 RT secured the binding mode and allowed the key interactions with the enzyme to be identified.
Asunto(s)
Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/farmacología , Transcriptasa Inversa del VIH/antagonistas & inhibidores , VIH-1/efectos de los fármacos , Inhibidores de la Transcriptasa Inversa/síntesis química , Inhibidores de la Transcriptasa Inversa/farmacología , Triazoles/síntesis química , Triazoles/farmacología , Fármacos Anti-VIH/química , Técnicas Químicas Combinatorias , Cristalografía por Rayos X , Conformación Molecular , Estructura Molecular , Inhibidores de la Transcriptasa Inversa/química , Relación Estructura-Actividad , Triazoles/químicaRESUMEN
Processes involving the creation and modification of oligomeric nucleotide substrates are key events in the replication cycles of many viruses, and have been successful targets for much pharmaceutical research. Because of high levels of intracellular divalent magnesium, and the high affinity of oxyanions for this hard Lewis acid, enzymes responsible for these transformations have evolved to use the divalent magnesium cation in their catalytic function. The interruption of enzyme function via active-site metal coordination has recently emerged as a viable approach to viral inhibition, and the most advanced programs in this field have now entered late-stage clinical trials, thus validating the approach. This review summarizes such programs that were initiated from alpha,gamma-diketo acid leads and that resulted in optimized candidates. Key relationships between structure and activity for successful high-affinity magnesium binding in the active site of these enzymes have been identified.
Asunto(s)
Antivirales/uso terapéutico , Quelantes del Hierro/uso terapéutico , Virosis/tratamiento farmacológico , Animales , Antivirales/química , Diseño de Fármacos , Humanos , Quelantes del Hierro/químicaRESUMEN
The use of a benzofuran to mask phenol and arylacetaldehyde moieties simultaneously in the synthesis of analogues of mycophenolic acid (MPA) was explored. Benzofuran 4 provided a stable and easily handled intermediate for the preparation of unnatural derivatives at the C-6 position of MPA. Preparation of the highly potent 6-ethyl MPA analogue 2 was accomplished via aldehyde 2c through this facile route with high-yielding steps and crystalline intermediates.
Asunto(s)
Aldehídos/química , Benzofuranos/química , Ácido Micofenólico/análogos & derivados , Ácido Micofenólico/síntesis química , Fenoles/química , Estructura Molecular , Ácido Micofenólico/química , EstereoisomerismoRESUMEN
The design, synthesis, and IMPDH inhibitory activity of a series of phosphonic acid-containing analogues of mycophenolic acid are described.
Asunto(s)
Inhibidores Enzimáticos/farmacología , IMP Deshidrogenasa/antagonistas & inhibidores , Ácido Micofenólico/farmacología , Organofosfonatos/química , Evaluación Preclínica de Medicamentos , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Estructura Molecular , Ácido Micofenólico/síntesis química , Ácido Micofenólico/química , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
[structure: see text] A flexible and efficient procedure has been developed for the conjugation of taxol to various arginine-based molecular transporters via the taxol C2' O-chloroacetyl derivative. The resultant taxol-transporter conjugates are highly water soluble and release free taxol with half-lives of minutes to hours depending on the pH and the linker structure.
Asunto(s)
Antineoplásicos/síntesis química , Arginina/análogos & derivados , Proteínas de Transporte de Membrana/síntesis química , Paclitaxel/química , Acetilación , Semivida , Concentración de Iones de Hidrógeno , Estructura Molecular , Solubilidad , EstereoisomerismoRESUMEN
Reductive photoinduced electron transfer (PET) reactions have been performed with various bicyclic alpha-cyclopropyl-substituted ketones and tertiary amines. The reaction resulted in a regioselective cleavage of one cyclopropyl bond under formation of an exocyclic radical with an endocyclic enolate unit. In the case of bicyclic ketones with an unsaturated side chain, various bicyclic, spirocyclic, and tricyclic products are accessible via radical cyclization, depending on the position of the alkenyl substituent. In addition to triethylamine, N-silylated amines have also been used as electron donors, leading to a variety of compounds, among them are silylated fragmentation products, indicating that a proton is transferred from not only the amine radical cation but also the cationic silyl group. The intramolecular Paternó-Büchi reaction has also been studied for cyclopropane derivatives of the jasmone type leading to tetracyclic oxetanes. Finally, alpha-epoxy-substituted ketones have been investigated under PET conditions, yielding ring-opened products.