RESUMEN
Emerging resistance to current antimalarial medicines underscores the importance of identifying new drug targets and novel compounds. Malaria parasites are purine auxotrophic and import purines via the Plasmodium falciparum equilibrative nucleoside transporter type 1 (PfENT1). We previously showed that PfENT1 inhibitors block parasite proliferation in culture. Our goal was to identify additional, possibly more optimal chemical starting points for a drug discovery campaign. We performed a high throughput screen (HTS) of GlaxoSmithKline's 1.8 million compound library with a yeast-based assay to identify PfENT1 inhibitors. We used a parallel progression strategy for hit validation and expansion, with an emphasis on chemical properties in addition to potency. In one arm, the most active hits were tested for human cell toxicity; 201 had minimal toxicity. The second arm, hit expansion, used a scaffold-based substructure search with the HTS hits as templates to identify over 2000 compounds; 123 compounds had activity. Of these 324 compounds, 175 compounds inhibited proliferation of P. falciparum parasite strain 3D7 with IC50 values between 0.8 and â¼180 µM. One hundred forty-two compounds inhibited PfENT1 knockout (pfent1Δ) parasite growth, indicating they also hit secondary targets. Thirty-two hits inhibited growth of 3D7 but not pfent1Δ parasites. Thus, PfENT1 inhibition was sufficient to block parasite proliferation. Therefore, PfENT1 may be a viable target for antimalarial drug development. Six compounds with novel chemical scaffolds were extensively characterized in yeast-, parasite-, and human-erythrocyte-based assays. The inhibitors showed similar potencies against drug sensitive and resistant P. falciparum strains. They represent attractive starting points for development of novel antimalarial drugs.
Asunto(s)
Antimaláricos/farmacología , Transporte Biológico/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Descubrimiento de Drogas , Plasmodium falciparum/efectos de los fármacos , Purinas/metabolismo , Antimaláricos/química , Eritrocitos/efectos de los fármacos , Técnicas de Inactivación de Genes , Células Hep G2/efectos de los fármacos , Ensayos Analíticos de Alto Rendimiento , Humanos , Malaria/parasitología , Malaria Falciparum/parasitología , Proteínas Portadoras de Nucleobases, Nucleósidos, Nucleótidos y Ácidos Nucleicos/efectos de los fármacos , Proteínas Portadoras de Nucleobases, Nucleósidos, Nucleótidos y Ácidos Nucleicos/genética , Plasmodium falciparum/genética , Plasmodium falciparum/crecimiento & desarrollo , Plasmodium falciparum/metabolismo , Proteínas Protozoarias/efectos de los fármacos , Proteínas Protozoarias/genética , Transcriptoma , Levaduras/efectos de los fármacosRESUMEN
The RecA/LexA axis of the bacterial DNA damage (SOS) response is a promising, yet nontraditional, drug target. The SOS response is initiated upon genotoxic stress, when RecA, a DNA damage sensor, induces LexA, the SOS repressor, to undergo autoproteolysis, thereby derepressing downstream genes that can mediate DNA repair and accelerate mutagenesis. As genetic inhibition of the SOS response sensitizes bacteria to DNA damaging antibiotics and decreases acquired resistance, inhibitors of the RecA/LexA axis could potentiate our current antibiotic arsenal. Compounds targeting RecA, which has many mammalian homologues, have been reported; however, small-molecules targeting LexA autoproteolysis, a reaction unique to the prokaryotic SOS response, have remained elusive. Here, we describe the logistics and accomplishments of an academic-industry partnership formed to pursue inhibitors against the RecA/LexA axis. A novel fluorescence polarization assay reporting on RecA-induced self-cleavage of LexA enabled the screening of 1.8 million compounds. Follow-up studies on select leads show distinct activity patterns in orthogonal assays, including several with activity in cell-based assays reporting on SOS activation. Mechanistic assays demonstrate that we have identified first-in-class small molecules that specifically target the LexA autoproteolysis step in SOS activation. Our efforts establish a realistic example for navigating academic-industry partnerships in pursuit of anti-infective drugs and offer starting points for dedicated lead optimization of SOS inhibitors that could act as adjuvants for current antibiotics.
Asunto(s)
Antibacterianos/aislamiento & purificación , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Proteínas Bacterianas/metabolismo , Colaboración Intersectorial , Proteolisis , Respuesta SOS en Genética/efectos de los fármacos , Serina Endopeptidasas/metabolismo , Investigación Biomédica/organización & administración , Descubrimiento de Drogas/organización & administración , Ensayos Analíticos de Alto Rendimiento , Inhibidores de Proteasas/aislamiento & purificación , Inhibidores de Proteasas/farmacologíaRESUMEN
Tyrosine ureas had been identified as potent muscarinic receptor antagonists with promising in vivo activity. Controlling the stereochemistry of the chiral quaternary ammonium center had proved to be a serious issue for this series, however. Herein we describe the preparation and SAR of tyrosine urea antagonists containing achiral quaternary ammonium centers. The most successful such moiety was the 2-methylimidazo[2,1-b][1,3]thiazol-7-ium group which yielded highly potent antagonists with long duration of action in an inhaled animal model of bronchoconstriction.
Asunto(s)
Antagonistas Muscarínicos/química , Compuestos de Amonio Cuaternario/química , Receptores Muscarínicos/química , Tirosina/química , Urea/análogos & derivados , Animales , Bronquios/efectos de los fármacos , Ratones , Antagonistas Muscarínicos/síntesis química , Antagonistas Muscarínicos/farmacología , Receptores Muscarínicos/metabolismo , Relación Estructura-Actividad , Urea/síntesis química , Urea/farmacologíaRESUMEN
A novel series of N-substituted tropane derivatives was characterized as potent muscarinic acetylcholine receptor antagonists (mAChRs). Kinetic washout studies showed that the N-endosubstituted analog 24 displayed much slower reversibility at mAChRs than the methyl-substituted parent molecule darotropium. In addition, it was shown that this characteristic appeared to translate into enhanced which duration of action in a mouse model of bronchonstriction.
Asunto(s)
Antagonistas Muscarínicos/síntesis química , Tropanos/síntesis química , Animales , Enfermedades Bronquiales/tratamiento farmacológico , Diseño de Fármacos , Ratones , Antagonistas Muscarínicos/farmacología , Receptores Muscarínicos/efectos de los fármacos , Relación Estructura-Actividad , Tropanos/farmacologíaRESUMEN
A series of azepanone inhibitors of cathepsin S is described. Selectivity over both cathepsin K and cathepsin L was achieved by varying the P2 substituent. Ultimately, a balanced potency and selectivity profile was achieved in compound 39 possessing a 1-methylcyclohexyl alanine at P2 and nicotinamide as the P' substituent. The cellular potency of selected analogs is also described.
Asunto(s)
Azepinas/química , Catepsinas/antagonistas & inhibidores , Niacinamida/análogos & derivados , Inhibidores de Proteasas/química , Alanina/química , Azepinas/síntesis química , Azepinas/farmacología , Sitios de Unión , Catepsina K/antagonistas & inhibidores , Catepsina K/metabolismo , Catepsina L/antagonistas & inhibidores , Catepsina L/metabolismo , Catepsinas/metabolismo , Simulación por Computador , Humanos , Niacinamida/síntesis química , Niacinamida/química , Niacinamida/farmacología , Inhibidores de Proteasas/síntesis química , Inhibidores de Proteasas/farmacología , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Novel tropane derivatives were characterized as muscarinic acetylcholine receptor antagonists (mAChRs). Through optimization of the structure-activity relationship around the tropane scaffold, the quaternary ammonium salt 34 was identified as a very potent M(3) mAChR antagonist. The compound was functionally active and displayed greater than 24 h duration of action in a mouse model of bronchoconstriction.
Asunto(s)
Compuestos de Bifenilo/síntesis química , Compuestos Bicíclicos Heterocíclicos con Puentes/síntesis química , Antagonistas Muscarínicos/síntesis química , Tropanos/síntesis química , Animales , Disponibilidad Biológica , Compuestos de Bifenilo/química , Compuestos de Bifenilo/farmacología , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Bronquios/efectos de los fármacos , Bronquios/fisiología , Broncoconstricción/efectos de los fármacos , Células CHO , Calcio/metabolismo , Cricetinae , Cricetulus , Diseño de Fármacos , Humanos , Técnicas In Vitro , Ratones , Ratones Endogámicos BALB C , Antagonistas Muscarínicos/química , Antagonistas Muscarínicos/farmacología , Contracción Muscular , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Ensayo de Unión Radioligante , Ratas , Receptor Muscarínico M1/fisiología , Receptor Muscarínico M2/fisiología , Receptor Muscarínico M3/fisiología , Estereoisomerismo , Relación Estructura-Actividad , Tropanos/química , Tropanos/farmacologíaRESUMEN
Design and syntheses of a novel series of muscarinic antagonists are reported. These efforts have culminated in the discovery of (3-endo)-3-(2-cyano-2,2-diphenylethyl)-8,8-dimethyl-8-azoniabicyclo[3.2.1]octane bromide (4a) as a potent and pan-active muscarinic antagonist as well as a functionally active compound in a murine model of bronchoconstriction. The compound has also displayed pharmacokinetic characteristics suitable for inhaled delivery.
Asunto(s)
Compuestos de Bifenilo/química , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Antagonistas Muscarínicos/química , Enfermedad Pulmonar Obstructiva Crónica/tratamiento farmacológico , Receptores Muscarínicos/química , Administración por Inhalación , Animales , Compuestos de Bifenilo/síntesis química , Compuestos de Bifenilo/farmacocinética , Compuestos Bicíclicos Heterocíclicos con Puentes/síntesis química , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacocinética , Descubrimiento de Drogas , Humanos , Ratones , Antagonistas Muscarínicos/síntesis química , Antagonistas Muscarínicos/farmacocinética , Ratas , Receptores Muscarínicos/metabolismo , Relación Estructura-ActividadRESUMEN
A novel 4-hydroxyl(diphenyl)methyl substituted quinuclidine series was discovered as a very promising class of muscarinic antagonists. The structure-activity relationships of the connectivity of the diphenyl moiety to the quinuclidine core and around the ring nitrogen side chain are described. Computational docking studies using an homology model of the M(3) receptor readily explained the observed structure-activity relationship of the various compounds. Compound 14o was identified as a very potent, slowly reversible M(3) antagonist with a very long in vivo duration of bronchoprotection.
Asunto(s)
Compuestos de Bencidrilo/síntesis química , Broncodilatadores/síntesis química , Quinuclidinas/síntesis química , Receptor Muscarínico M3/antagonistas & inhibidores , Animales , Compuestos de Bencidrilo/química , Compuestos de Bencidrilo/farmacología , Disponibilidad Biológica , Bronquios/efectos de los fármacos , Bronquios/fisiología , Broncoconstricción/efectos de los fármacos , Broncodilatadores/química , Broncodilatadores/farmacología , Células CHO , Calcio/metabolismo , Cricetinae , Cricetulus , Humanos , Técnicas In Vitro , Ratones , Modelos Moleculares , Contracción Muscular , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Quinuclidinas/química , Quinuclidinas/farmacología , Ensayo de Unión Radioligante , Ratas , Relación Estructura-ActividadRESUMEN
A series of N-arylpiperazine camphor sulfonamides was discovered as novel CXCR3 antagonists. The synthesis, structure-activity relationships, and optimization of the initial hit that resulted in the identification of potent and selective CXCR3 antagonists are described.
Asunto(s)
Alcanfor/análogos & derivados , Receptores CXCR3/antagonistas & inhibidores , Sulfonamidas/síntesis química , Alcanfor/síntesis química , Alcanfor/farmacología , Humanos , Piperazinas , Relación Estructura-Actividad , Sulfonamidas/farmacologíaRESUMEN
In the course of our research program to develop novel muscarinic receptor antagonists for the treatment of COPD, new tropane carbamate derivatives were identified as potent anti-muscarinic agents. The synthesis, structure-activity relationships and pharmacological evaluation that led to the identification of compound 5o, are described.
Asunto(s)
Compuestos Bicíclicos Heterocíclicos con Puentes/síntesis química , Carbamatos/síntesis química , Antagonistas Muscarínicos , Receptores Muscarínicos/efectos de los fármacos , Tropanos/síntesis química , Animales , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Broncodilatadores/síntesis química , Broncodilatadores/química , Broncodilatadores/farmacología , Carbamatos/química , Carbamatos/farmacología , Evaluación Preclínica de Medicamentos , Concentración 50 Inhibidora , Ratones , Estructura Molecular , Antagonistas Muscarínicos/síntesis química , Antagonistas Muscarínicos/química , Antagonistas Muscarínicos/farmacología , Enfermedad Pulmonar Obstructiva Crónica/terapia , Tropanos/química , Tropanos/farmacologíaRESUMEN
A series of 3-arylamino-2H-1,2,4-benzothiadiazin-5-ol 1,1-dioxides were prepared and shown to be novel and selective antagonists of the CXCR2 receptor. Synthesis, structure and activity relationships, selectivity, and some developability properties are described.
Asunto(s)
Benzotiadiazinas/farmacología , Receptores de Interleucina-8B/antagonistas & inhibidores , Benzotiadiazinas/química , Relación Estructura-ActividadRESUMEN
N,N'-diarylsquaramides were prepared and evaluated as antagonists of CXCR2. The compounds were found to be potent and selective antagonists of CXCR2. Significant differences in SAR was observed relative to the previously described N,N'-diarylurea series. As was the case in the N,N'-diarylurea series, placing sulfonamide substituent adjacent to the acidic phenol significantly reduced the clearance in rat pharmacokinetic studies.
Asunto(s)
Ciclobutanos/síntesis química , Ciclobutanos/farmacología , Ciclobutanos/farmacocinética , Receptores de Interleucina-8B/antagonistas & inhibidores , Urea/análogos & derivados , Urea/síntesis química , Urea/farmacología , Urea/farmacocinética , Animales , Células CHO , Fenómenos Químicos , Química Física , Cricetinae , Cricetulus , Indicadores y Reactivos , Espectrometría de Masas , Fenoles/química , Ratas , Ratas Sprague-Dawley , Relación Estructura-Actividad , Sulfonamidas/químicaRESUMEN
A series of N-(2-hydroxy-3-sulfonamidobenzene)-N'-arylcyanoguanidines was prepared. In general, these compounds proved to be potent antagonists of CXCR2 while the selectivity versus CXCR1 ranged from non-selective to >200-fold.
Asunto(s)
Guanidinas/farmacología , Receptores de Interleucina-8A/antagonistas & inhibidores , Receptores de Interleucina-8B/antagonistas & inhibidores , Guanidinas/química , HumanosRESUMEN
A series of 3-substituted N,N'-diarylureas was prepared and the structure-activity relationship relative to CXCR2 receptor affinity as well as their pharmacokinetic properties were examined. In vitro microsomal metabolism studies indicated that the lower clearance rates of the 3-sulfonamido-substituted compounds were most likely due to the suppression of glucuronidation.
Asunto(s)
Receptores de Interleucina-8B/antagonistas & inhibidores , Compuestos de Sulfonilurea/química , Administración Oral , Animales , Disponibilidad Biológica , Humanos , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Unión Proteica/efectos de los fármacos , Unión Proteica/fisiología , Ratas , Ratas Sprague-Dawley , Receptores de Interleucina-8B/metabolismo , Compuestos de Sulfonilurea/metabolismo , Compuestos de Sulfonilurea/farmacologíaRESUMEN
N,N'-Diarylureas were prepared, and the structure-activity relationship relative to the CXCR2 receptor was examined. This led to the identification of a potent and highly selective CXCR2 antagonist, which in addition was shown to be functionally active both in vitro against human neutrophils and in vivo in rabbit models of ear edema and neutropenia.
Asunto(s)
Antiinflamatorios/síntesis química , Compuestos de Fenilurea/síntesis química , Receptores de Interleucina-8B/antagonistas & inhibidores , Animales , Antiinflamatorios/química , Antiinflamatorios/farmacología , Unión Competitiva , Células CHO , Calcio/metabolismo , Quimiocina CXCL1 , Quimiocinas , Factores Quimiotácticos , Quimiotaxis , Cricetinae , Humanos , Hipersensibilidad Tardía/inducido químicamente , Hipersensibilidad Tardía/tratamiento farmacológico , Técnicas In Vitro , Péptidos y Proteínas de Señalización Intercelular , Interleucina-8 , Neutropenia/inducido químicamente , Neutropenia/tratamiento farmacológico , Neutrófilos/efectos de los fármacos , Neutrófilos/metabolismo , Neutrófilos/fisiología , Compuestos de Fenilurea/química , Compuestos de Fenilurea/farmacología , Conejos , Ensayo de Unión Radioligante , Receptores de Interleucina-8A/antagonistas & inhibidores , Receptores de Interleucina-8A/metabolismo , Receptores de Interleucina-8B/metabolismo , Relación Estructura-ActividadRESUMEN
Much evidence implicates IL-8 as a major mediator of inflammation and joint destruction in rheumatoid arthritis. The effects of IL-8 and its related ligands are mediated via two receptors, CXCR1 and CXCR2. In the present study, we demonstrate that a potent and selective nonpeptide antagonist of human CXCR2 potently inhibits (125)I-labeled human IL-8 binding to, and human IL-8-induced calcium mobilization mediated by, rabbit CXCR2 (IC(50) = 40.5 and 7.7 nM, respectively), but not rabbit CXCR1 (IC(50) = >1000 and 2200 nM, respectively). These data suggest that the rabbit is an appropriate species in which to examine the anti-inflammatory effects of a human CXCR2-selective antagonist. In two acute models of arthritis in the rabbit induced by knee joint injection of human IL-8 or LPS, and a chronic Ag (OVA)-induced arthritis model, administration of the antagonist at 25 mg/kg by mouth twice a day significantly reduced synovial fluid neutrophils, monocytes, and lymphocytes. In addition, in the more robust LPS- and OVA-induced arthritis models, which were characterized by increased levels of proinflammatory mediators in the synovial fluid, TNF-alpha, IL-8, PGE(2), leukotriene B(4), and leukotriene C(4) levels were significantly reduced, as was erythrocyte sedimentation rate, possibly as a result of the observed decreases in serum TNF-alpha and IL-8 levels. In vitro, the antagonist potently inhibited human IL-8-induced chemotaxis of rabbit neutrophils (IC(50) = 0.75 nM), suggesting that inhibition of leukocyte migration into the knee joint is a likely mechanism by which the CXCR2 antagonist modulates disease.