RESUMEN
Ribonucleoside analog inhibitors (rNAI) target the hepatitis C virus (HCV) RNA-dependent RNA polymerase nonstructural protein 5B (NS5B) and cause RNA chain termination. Here, we expand our studies on ß-d-2'-C-methyl-2,6-diaminopurine-ribonucleotide (DAPN) phosphoramidate prodrug 1 (PD1) as a novel investigational inhibitor of HCV. DAPN-PD1 is metabolized intracellularly into two distinct bioactive nucleoside triphosphate (TP) analogs. The first metabolite, 2'-C-methyl-GTP, is a well-characterized inhibitor of NS5B polymerase, whereas the second metabolite, 2'-C-methyl-DAPN-TP, behaves as an adenosine base analog. In vitro assays suggest that both metabolites are inhibitors of NS5B-mediated RNA polymerization. Additional factors, such as rNAI-TP incorporation efficiencies, intracellular rNAI-TP levels, and competition with natural ribonucleotides, were examined in order to further characterize the potential role of each nucleotide metabolite in vivo Finally, we found that although both 2'-C-methyl-GTP and 2'-C-methyl-DAPN-TP were weak substrates for human mitochondrial RNA (mtRNA) polymerase (POLRMT) in vitro, DAPN-PD1 did not cause off-target inhibition of mtRNA transcription in Huh-7 cells. In contrast, administration of BMS-986094, which also generates 2'-C-methyl-GTP and previously has been associated with toxicity in humans, caused detectable inhibition of mtRNA transcription. Metabolism of BMS-986094 in Huh-7 cells leads to 87-fold higher levels of intracellular 2'-C-methyl-GTP than DAPN-PD1. Collectively, our data characterize DAPN-PD1 as a novel and potent antiviral agent that combines the delivery of two active metabolites.
Asunto(s)
Adenosina/análogos & derivados , Antivirales/farmacología , Guanosina Monofosfato/análogos & derivados , Hepacivirus/efectos de los fármacos , Hepatitis C/tratamiento farmacológico , Profármacos/farmacología , Sofosbuvir/farmacología , Adenosina/farmacología , Línea Celular , ARN Polimerasas Dirigidas por ADN/metabolismo , Guanosina Monofosfato/farmacología , Humanos , ARN/metabolismo , ARN Mitocondrial , ARN Viral/metabolismo , Ribonucleósidos/metabolismo , Transcripción Genética/efectos de los fármacos , Proteínas no Estructurales Virales/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
One in five of the world's plant species is threatened with extinction according to the 2010 first global analysis of extinction risk. Tilman et al. predicted a massive ecological change to terrestrial plants within the next 50-100 y, accompanied by an increase in the number of global plant species facing extinction [Tilman D, et al. (2001) Proc Natl Acad Sci USA 98(10):5433-5440]. Most of the drug-producing plant families contain endangered species never previously studied for their utility to human health, which strongly validates the need to prioritize protection and assessment of these fragile and endangered groups [Zhu F, et al. (2011) Proc Natl Acad Sci USA 108(31):12943-12948]. With little prior attention given to endangered and rare plant species, this report provides strong justification for conservation of the rare plant Diplostephium rhododendroides Hieron., as well as other potential drug-producing endangered species in this and other groups.
Asunto(s)
Asteraceae/fisiología , Especies en Peligro de Extinción , Plantas Medicinales/fisiología , Diabetes Mellitus/tratamiento farmacológico , Humanos , Fitoterapia/métodosRESUMEN
The design and synthesis of new non-symmetrical NS5A inhibitors with sulfur containing amino acids is reported along with their ability to block HCV replication in an HCV 1b replicon system. These compounds display EC50 values in the picomolar range with a large therapeutic index (>10(6)). Moreover, cellular pharmacology studies show that our preferred compounds intracellularly deliver three potent NS5A inhibitors.
Asunto(s)
Antivirales/química , Antivirales/farmacología , Hepacivirus/efectos de los fármacos , Proteínas no Estructurales Virales/antagonistas & inhibidores , Animales , Antivirales/administración & dosificación , Carbamatos , Línea Celular/efectos de los fármacos , Línea Celular/virología , Técnicas de Química Sintética , Chlorocebus aethiops , Diseño de Fármacos , Evaluación Preclínica de Medicamentos/métodos , Hepacivirus/genética , Humanos , Imidazoles/farmacología , Terapia Molecular Dirigida , Mutación , Pirrolidinas , Relación Estructura-Actividad , Valina/análogos & derivados , Células Vero/efectos de los fármacos , Proteínas no Estructurales Virales/química , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
The synthesis of new 2,6-disubstituted purine 2',3'-dideoxy-2',3'-difluoro-D-arabino nucleosides is reported. Their ability to block HIV and HCV replication along with their cytotoxicity toward Huh-7 cells, human lymphocyte, CEM and Vero cells was also assessed. Among them, ß-2,6-diaminopurine nucleoside 25 and guanosine derivative 27 demonstrate potent anti-HIV-1 activity (EC50 = 0.56 and 0.65 µM; EC90 = 4.2 and 3.1 µM) while displaying only moderate cytotoxicity in primary human lymphocytes.
RESUMEN
The synthesis of new ribo and 2'-ß-C-methyl ribo Janus type nucleosides J-AA, J-AG and J-AU is reported along with their ability to block HCV and HIV replication. Their toxicity was also assessed in Huh7, human lymphocytes, CEM and Vero cells.
Asunto(s)
Inhibidores Enzimáticos/síntesis química , Hepacivirus/enzimología , Nucleósidos/química , Proteínas no Estructurales Virales/antagonistas & inhibidores , Animales , Línea Celular , Chlorocebus aethiops , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Humanos , Nucleósidos/síntesis química , Nucleósidos/farmacología , Relación Estructura-Actividad , Células Vero , Proteínas no Estructurales Virales/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
Herein, we report the synthesis and structure-activity relationship studies of new analogs of boceprevir 1 and telaprevir 2. Introduction of azetidine and spiroazetidines as a P2 substituent that replaced the pyrrolidine moiety of 1 and 2 led to the discovery of a potent hepatitis C protease inhibitor 37c (EC50=0.8 µM).
Asunto(s)
Antivirales/farmacología , Azetidinas/química , Azetidinas/farmacología , Hepatitis C/tratamiento farmacológico , Inhibidores de Proteasas/farmacología , Proteínas no Estructurales Virales/antagonistas & inhibidores , Proteínas no Estructurales Virales/química , Antivirales/síntesis química , Antivirales/química , Diseño de Fármacos , Humanos , Modelos Moleculares , Inhibidores de Proteasas/síntesis química , Inhibidores de Proteasas/química , Relación Estructura-ActividadRESUMEN
Based on the symmetrical bidentate structure of the NS5A inhibitor BMS-790052, a series of new monodentate molecules were designed. The synthesis of 36 new non-dimeric NS5A inhibitors is reported along with their ability to block HCV replication in an HCV 1b replicon system. Among them compound 5a showed picomolar range activity along with an excellent selectivity index (SI > 90,000).
Asunto(s)
Imidazoles/farmacología , Proteínas no Estructurales Virales/antagonistas & inhibidores , Animales , Antivirales/síntesis química , Antivirales/química , Antivirales/farmacología , Carbamatos , Línea Celular , Chlorocebus aethiops , Relación Dosis-Respuesta a Droga , Hepacivirus/efectos de los fármacos , Humanos , Imidazoles/síntesis química , Imidazoles/química , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Pirrolidinas , Relación Estructura-Actividad , Valina/análogos & derivados , Células Vero , Replicación Viral/efectos de los fármacosRESUMEN
NS5A inhibitors are a new class of direct-acting antiviral agents which display very potent anti-HCV activity in vitro and in humans. Rationally designed modifications to the central biphenyl linkage of a known NS5A series led to selection of several compounds that were synthesized and evaluated in a HCV genotype 1b replicon. The straight triphenyl linked compound 11a showed similar anti-HCV activity to the clinical compound BMS-790052 and a superior cytotoxicity profile in three different cell lines, with an EC(50) value of 26 pM and a therapeutic index of over four million in an HCV replicon assay. This triphenyl analog warrants further preclinical evaluation as an anti-HCV agent.
Asunto(s)
Antivirales/síntesis química , Antivirales/farmacología , Hepacivirus/efectos de los fármacos , Proteínas no Estructurales Virales/antagonistas & inhibidores , Línea Celular , Humanos , Pruebas de Sensibilidad MicrobianaRESUMEN
Judicious modifications to the structure of the previously reported HCV NS5A inhibitor 1, resulted in more potent anti-HCV compounds with similar and in some cases improved toxicity profiles. The synthesis of 19 new NS5A inhibitors is reported along with their ability to block HCV replication in an HCV 1b replicon system. For the most potent compounds chemical stability, stability in liver microsomes and inhibition of relevant CYP450 enzymes is also presented.
Asunto(s)
Antivirales/síntesis química , Hepacivirus/efectos de los fármacos , Antivirales/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Humanos , Microsomas Hepáticos/efectos de los fármacos , Estructura Molecular , Relación Estructura-ActividadRESUMEN
A series of 2',3'-dideoxy-2',2'-difluoro-4'-azanucleosides of both pyrimidine and purine nucleobases were synthesized in an efficient manner starting from commercially available L-pyroglutamic acid via glycosylation of difluorinated pyrrolidine derivative 15. Several 4'-azanucleosides were prepared as a separable mixture of α- and ß-anomers. The 6-chloropurine analogue was obtained as a mixture of N(7) and N(9) regioisomers and their structures were identified based on NOESY and HMBC spectral data. Among the 4'-azanucleosides tested as HIV-1 inhibitors in primary human lymphocytes, four compounds showed modest activity and the 5-fluorouracil analogue (18d) was found to be the most active compound (EC(50)=36.9µM) in this series. None of the compounds synthesized in this study demonstrated anti-HCV activity.
Asunto(s)
Antivirales/química , Antivirales/farmacología , VIH-1/efectos de los fármacos , Hepacivirus/efectos de los fármacos , Nucleósidos/química , Nucleósidos/farmacología , Antivirales/síntesis química , Antivirales/toxicidad , Compuestos Aza/síntesis química , Compuestos Aza/química , Compuestos Aza/farmacología , Compuestos Aza/toxicidad , Infecciones por VIH/tratamiento farmacológico , Halogenación , Hepatitis C/tratamiento farmacológico , Humanos , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/virología , Nucleósidos/síntesis química , Nucleósidos/toxicidadRESUMEN
Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.
Asunto(s)
Envejecimiento , Anfibios , Evolución Biológica , Reptiles , Anfibios/clasificación , Anfibios/fisiología , Animales , Longevidad , Filogenia , Reptiles/clasificación , Reptiles/fisiologíaRESUMEN
Based on the anti-hepatitis C activity of 2'-C-methyl-adenosine and 2'-C-methyl-guanosine, a series of new modified purine 2'-C-methyl nucleosides was prepared as potential anti-hepatitis C virus agents. Herein, we report the synthesis of both 6-modified and 2-modified purine 2'-C-methyl-nucleosides along with their anti-HCV replication activity and cytotoxicity in different cells.
Asunto(s)
Antivirales/química , Antivirales/farmacología , Hepacivirus/efectos de los fármacos , Nucleósidos de Purina/química , Nucleósidos de Purina/farmacología , Animales , Antivirales/síntesis química , Línea Celular , Supervivencia Celular/efectos de los fármacos , Hepatitis C/tratamiento farmacológico , Humanos , Nucleósidos de Purina/síntesis químicaRESUMEN
Thirty novel α- and ß-d-2'-deoxy-2'-fluoro-2'-C-methyl-7-deazapurine nucleoside analogs were synthesized and evaluated for in vitro antiviral activity. Several α- and ß-7-deazapurine nucleoside analogs exhibited modest anti-HCV activity and cytotoxicity. Four synthesized 7-deazapurine nucleoside phosphoramidate prodrugs (18-21) showed no anti-HCV activity, whereas the nucleoside triphosphates (22-24) demonstrated potent inhibitory effects against both wild-type and S282T mutant HCV polymerases. Cellular pharmacology studies in Huh-7 cells revealed that the 5'-triphosphates were not formed at significant levels from either the nucleoside or the phosphoramidate prodrugs, indicating that insufficient phosphorylation was responsible for the lack of anti-HCV activity. Evaluation of anti-HIV-1 activity revealed that an unusual α-form of 7-carbomethoxyvinyl substituted nucleoside (10) had good anti-HIV-1 activity (EC(50)=0.71±0.25 µM; EC(90)=9.5±3.3 µM) with no observed cytotoxicity up to 100 µM in four different cell lines.
Asunto(s)
Antivirales , Hepacivirus/efectos de los fármacos , Nucleósidos , Profármacos , Amidas/síntesis química , Amidas/farmacología , Antivirales/síntesis química , Antivirales/farmacología , Línea Celular , Flúor/química , Humanos , Concentración 50 Inhibidora , Estructura Molecular , Nucleósidos/síntesis química , Nucleósidos/farmacología , Ácidos Fosfóricos/síntesis química , Ácidos Fosfóricos/farmacología , Profármacos/síntesis química , Profármacos/farmacología , Purinas/síntesis química , Purinas/química , Purinas/farmacología , Replicación Viral/efectos de los fármacosRESUMEN
Based on the promising drug resistance profile and potent anti-HIV activity of beta-d-3'-azido-2',3'-dideoxyguanosine, a series of purine modified nucleosides were synthesized by a chemical transglycosylation reaction and evaluated for their antiviral activity, cytotoxicity, and intracellular metabolism. Among the synthesized compounds, several show potent and selective anti-HIV activity in primary lymphocytes.
Asunto(s)
Fármacos Anti-VIH/síntesis química , Didesoxinucleósidos/síntesis química , Transcriptasa Inversa del VIH/antagonistas & inhibidores , Fármacos Anti-VIH/química , Fármacos Anti-VIH/toxicidad , Didesoxinucleósidos/química , Didesoxinucleósidos/toxicidad , Glicosilación , Transcriptasa Inversa del VIH/metabolismo , Humanos , Linfocitos/efectos de los fármacos , Linfocitos/inmunologíaRESUMEN
Hepatitis C virus (HCV) nucleoside inhibitors display pan-genotypic activity, a high barrier to the selection of resistant virus, and are some of the most potent direct-acting agents with durable sustained virologic response in humans. Herein, we report, the discovery of ß-d-2'-Br,2'-F-uridine phosphoramidate diastereomers 27 and 28, as nontoxic pan-genotypic anti-HCV agents. Extensive profiling of these two phosphorous diastereomers was performed to select one for in-depth preclinical profiling. The 5'-triphosphate formed from these phosphoramidates selectively inhibited HCV NS5B polymerase with no inhibition of human polymerases and cellular mitochondrial RNA polymerase up to 100 µM. Both are nontoxic by a variety of measures and display good stability in human blood and favorable metabolism in human intestinal microsomes and liver microsomes. Ultimately, a preliminary oral pharmacokinetics study in male beagles showed that 28 is superior to 27 and is an attractive candidate for further studies to establish its potential value as a new clinical anti-HCV agent.
Asunto(s)
Antivirales/farmacología , Desoxirribonucleósidos/farmacología , Nucleótidos de Desoxiuracil/farmacología , Hepacivirus/efectos de los fármacos , Profármacos/farmacología , Animales , Antivirales/síntesis química , Antivirales/farmacocinética , Línea Celular Tumoral , Desoxirribonucleósidos/síntesis química , Desoxirribonucleósidos/farmacocinética , Nucleótidos de Desoxiuracil/síntesis química , Nucleótidos de Desoxiuracil/farmacocinética , Perros , Descubrimiento de Drogas , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacocinética , Inhibidores Enzimáticos/farmacología , Humanos , Masculino , Microsomas Hepáticos/metabolismo , Profármacos/síntesis química , Profármacos/farmacocinética , Proteínas no Estructurales Virales/antagonistas & inhibidoresRESUMEN
New Zealand has a diverse, endemic skink fauna, which is recognised as the most species rich skink assemblage of any cool temperate region on earth. All native New Zealand skink species are assigned to a single genus, Oligosoma Girard. A new species of Oligosoma is described from screes in montane tussock grassland in the mid-Canterbury high country, New Zealand, where it is currently known from four sites on two mountain ranges. The new species (Oligosoma hoparatea sp. nov.) can be distinguished from all congeners by a combination of mid-body scale row and lamellae counts, scale morphologies, and a bold striped pattern with smooth-edged, dark lateral bands. It is part of the O. longipes Patterson species complex, and occurs in sympatry with its closest relative, O. aff. longipes 'southern'. The species is currently highly threatened, and is listed as Nationally Critical in New Zealand. Predation by a suite of introduced mammals is assumed to be a major threat to its survival.
Asunto(s)
Lagartos , Animales , Nueva Zelanda , FilogeniaRESUMEN
(-)-(2R,4R)-1-(2-Hydroxymethyl-1,3-dioxolan-4yl)thymine (DOT) is a thymidine analogue that has potent in vitro activity against wild-type and nucleoside reverse transcriptase inhibitor (NRTI)-resistant HIV. For nucleoside analogues to inhibit viral replication, they must be metabolized to the active triphosphate, which inhibits the viral reverse transcriptase (RT). Using purified enzymes, the kinetics of DOT phosphorylation, inhibition of wild-type and drug-resistant HIV-1 reverse transcriptase activity, and excision of DOT-5'-monophosphate (DOT-MP) from a chain-terminated primer were examined. DOT was phosphorylated by human thymidine kinase-1 (TK-1) but not by other pyrimidine nucleoside kinases, including the mitochondrial thymidine kinase (TK-2). Resistance to NRTIs involves decreased binding/incorporation and/or increased excision of the chain-terminating NRTI. RTs containing the D67N/K70R/T215Y/K219Q or T695-SS/T215Y mutations show enhanced removal of DOT-MP from terminated primer as well as approximately four-fold decreased binding/incorporation. The Q151M and K65R mutations appear to cause decreased inhibition by DOT-TP. However, both the K65R and Q151M mutations show decreased excision, which would confer greater stability on the terminated primer. These opposing mechanisms could offset the overall resistance profile and susceptibility. Little or no resistance was observed with the enzymes harbouring mutations resistant to lamivudine (M184V) and non-nucleoside RT inhibitors (K103N).
Asunto(s)
Fármacos Anti-VIH/farmacología , Transcriptasa Inversa del VIH/antagonistas & inhibidores , Inhibidores de la Transcriptasa Inversa/farmacología , Timina/análogos & derivados , Adenosina Trifosfato/farmacología , Farmacorresistencia Viral , Fosforilación , Timina/farmacologíaRESUMEN
Pan-genotypic nucleoside HCV inhibitors display a high genetic barrier to drug resistance and are the preferred direct-acting agents to achieve complete sustained virologic response in humans. Herein, we report, the discovery of a ß-d-2'-Cl,2'-F-uridine phosphoramidate nucleotide 16, as a nontoxic pan-genotypic anti-HCV agent. Phosphoramidate 16 in its 5'-triphosphate form specifically inhibited HCV NS5B polymerase with no marked inhibition of human polymerases and cellular mitochondrial RNA polymerase. Studies on the intracellular half-life of phosphoramidate 16-TP in live cells demonstrated favorable half-life of 11.6 h, suggesting once-a-day dosing. Stability in human blood and favorable metabolism in human intestinal microsomes and liver microsomes make phosphoramidate 16 a prospective candidate for further studies to establish its potential value as a new anti-HCV agent.
Asunto(s)
Antivirales/farmacología , Hepacivirus/efectos de los fármacos , Profármacos/farmacología , Ribonucleótidos/farmacología , Antivirales/síntesis química , Antivirales/química , Células Cultivadas , Relación Dosis-Respuesta a Droga , Genotipo , Células Hep G2 , Hepacivirus/genética , Humanos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Profármacos/síntesis química , Profármacos/química , Ribonucleótidos/síntesis química , Ribonucleótidos/química , Relación Estructura-Actividad , Proteínas no Estructurales Virales/antagonistas & inhibidores , Proteínas no Estructurales Virales/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
A variety of 2,6-modified purine 2'-C-methylribonucleosides and their phosphoramidate prodrugs were synthesized and evaluated for inhibition of HCV RNA replication in Huh-7 cells and for cytotoxicity in various cell lines. Cellular pharmacology and HCV polymerase incorporation studies on the most potent and selective compound are reported.
RESUMEN
We recently discovered a novel compound, identified as N3, 5-cyclo-4-(beta-D-ribofuranosyl)-vic-triazolo[4,5-b]pyridinin-5-one, with anti-hepatitis C virus (HCV) activity in vitro. The structure was confirmed by chemical synthesis from 2-hydroxy-5-nitropyridine. It showed anti-HCV activity with EC50= 19.7 microM in replicon cells. Its 3'-deoxy sugar analogue was also synthesized, but was inactive against HCV in vitro.