RESUMO
Dietary supplements and natural products are often marketed as safe and effective alternatives to conventional drugs, but their safety and efficacy are not well regulated. To address the lack of scientific data in these areas, we assembled a collection of Dietary Supplements and Natural Products (DSNP), as well as Traditional Chinese Medicinal (TCM) plant extracts. These collections were then profiled in a series of in vitro high-throughput screening assays, including a liver cytochrome p450 enzyme panel, CAR/PXR signaling pathways, and P-glycoprotein (P-gp) transporter assay activities. This pipeline facilitated the interrogation of natural product-drug interaction (NaPDI) through prominent metabolizing pathways. In addition, we compared the activity profiles of the DSNP/TCM substances with those of an approved drug collection (the NCATS Pharmaceutical Collection or NPC). Many of the approved drugs have well-annotated mechanisms of action (MOAs), while the MOAs for most of the DSNP and TCM samples remain unknown. Based on the premise that compounds with similar activity profiles tend to share similar targets or MOA, we clustered the library activity profiles to identify overlap with the NPC to predict the MOAs of the DSNP/TCM substances. Our results suggest that many of these substances may have significant bioactivity and potential toxicity, and they provide a starting point for further research on their clinical relevance.
RESUMO
The global health emergency posed by the outbreak of Zika virus (ZIKV), an arthropod-borne flavivirus causing severe neonatal neurological conditions, has subsided, but there continues to be transmission of ZIKV in endemic regions. As such, there is still a medical need for discovering and developing therapeutical interventions against ZIKV. To identify small-molecule compounds that inhibit ZIKV disease and transmission, we screened multiple small-molecule collections, mostly derived from natural products, for their ability to inhibit wild-type ZIKV. As a primary high-throughput screen, we used a viral cytopathic effect (CPE) inhibition assay conducted in Vero cells that was optimized and miniaturized to a 1536-well format. Suitably active compounds identified from the primary screen were tested in a panel of orthogonal assays using recombinant Zika viruses, including a ZIKV Renilla luciferase reporter assay and a ZIKV mCherry reporter system. Compounds that were active in the wild-type ZIKV inhibition and ZIKV reporter assays were further evaluated for their inhibitory effects against other flaviviruses. Lastly, we demonstrated that wild-type ZIKV is able to infect a 3D-bioprinted outer-blood-retina barrier tissue model and disrupt its barrier function, as measured by electrical resistance. One of the identified compounds (3-Acetyl-13-deoxyphomenone, NCGC00380955) was able to prevent the pathological effects of the viral infection on this clinically relevant ZIKV infection model.
Assuntos
Antivirais/farmacologia , Modelos Biológicos , Impressão Tridimensional , Retina , Replicação Viral/efeitos dos fármacos , Infecção por Zika virus , Zika virus/fisiologia , Animais , Antivirais/química , Chlorocebus aethiops , Avaliação Pré-Clínica de Medicamentos , Células Hep G2 , Humanos , Retina/metabolismo , Retina/virologia , Células Vero , Replicação Viral/genética , Infecção por Zika virus/tratamento farmacológico , Infecção por Zika virus/genética , Infecção por Zika virus/metabolismoRESUMO
Neomorphic mutations in isocitrate dehydrogenase 1 (IDH1) are oncogenic for a number of malignancies, primarily low-grade gliomas and acute myeloid leukemia. We report a medicinal chemistry campaign around a 7,7-dimethyl-7,8-dihydro-2H-1λ2-quinoline-2,5(6H)-dione screening hit against the R132H and R132C mutant forms of isocitrate dehydrogenase (IDH1). Systematic SAR efforts produced a series of potent pyrid-2-one mIDH1 inhibitors, including the atropisomer (+)-119 (NCATS-SM5637, NSC 791985). In an engineered mIDH1-U87-xenograft mouse model, after a single oral dose of 30 mg/kg, 16 h post dose, between 16 and 48 h, (+)-119 showed higher tumoral concentrations that corresponded to lower 2-HG concentrations, when compared with the approved drug AG-120 (ivosidenib).
Assuntos
Inibidores Enzimáticos/química , Isocitrato Desidrogenase/antagonistas & inibidores , Piridonas/química , Animais , Encéfalo/metabolismo , Linhagem Celular Tumoral , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/uso terapêutico , Feminino , Glicina/análogos & derivados , Glicina/uso terapêutico , Meia-Vida , Humanos , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Camundongos , Camundongos Nus , Microssomos Hepáticos/metabolismo , Mutagênese Sítio-Dirigida , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Piridinas/uso terapêutico , Piridonas/metabolismo , Piridonas/uso terapêutico , Ratos , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen â¼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.
Assuntos
Antivirais/análise , Antivirais/farmacologia , Avaliação Pré-Clínica de Medicamentos , Ensaios de Triagem em Larga Escala , Inibidores de Proteases/análise , Inibidores de Proteases/farmacologia , Zika virus/efeitos dos fármacos , Animais , Antivirais/uso terapêutico , Inteligência Artificial , Chlorocebus aethiops , Modelos Animais de Doenças , Imunocompetência , Concentração Inibidora 50 , Metaciclina/farmacologia , Camundongos Endogâmicos C57BL , Inibidores de Proteases/uso terapêutico , Relação Quantitativa Estrutura-Atividade , Bibliotecas de Moléculas Pequenas , Células Vero , Infecção por Zika virus/tratamento farmacológico , Infecção por Zika virus/virologiaRESUMO
AlphaScreen technology has been routinely utilized in high-throughput screening assays to quantify analyte accumulation or depletion, bimolecular interactions, and post-translational modifications. The high signal-to-background, dynamic range, and sensitivity associated with AlphaScreens as well as the homogenous assay format and reagent stability make the technology particularly well suited for high-throughput screening applications. Here, we describe the development of AlphaScreen assays to identify small-molecule inhibitors of enzymes and protein-protein interactions using the highly miniaturized 1536-well format. The subsequent implementation of counter assays to identify false-positive compounds is also discussed.
Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Ensaios Enzimáticos/métodos , Inibidores Enzimáticos/farmacologia , Ensaios de Triagem em Larga Escala/métodos , Medições Luminescentes/métodos , Mapas de Interação de Proteínas/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Linhagem Celular , HumanosRESUMO
Testing small molecules for their ability to modify cysteine residues of proteins in the early stages of drug discovery is expected to accelerate our ability to develop more selective drugs with lesser side effects. In addition, this approach also enables the rapid evaluation of the mode of binding of new drug candidates with respect to thiol reactivity and metabolism by glutathione. Herein, we describe the development of a fluorescence-based high-throughput assay that allows the identification of thiol-reactive compounds. A thiol-containing fluorescent probe, MSTI, was synthesized and used to evaluate small molecules from the Library of Pharmacologically Active Compounds (LOPAC) collection of bioactive molecules. LOPAC compounds that are known to react with sulfur nucleophiles were identified with this assay, for example, irreversible protease inhibitors, nitric oxide-releasing compounds, and proton-pump inhibitors. The results confirm that both electrophilic and redox reactive compounds can be quickly identified in a high-throughput manner, enabling the assessment of screening libraries with respect to thiol-reactive compounds.
Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Corantes Fluorescentes/química , Ensaios de Triagem em Larga Escala/métodos , Bibliotecas de Moléculas Pequenas/farmacologia , Compostos de Sulfidrila/química , Descoberta de Drogas/métodos , Fluorescência , Glutationa/metabolismo , Óxido Nítrico/metabolismo , Oxirredução/efeitos dos fármacos , Inibidores de Proteases/farmacologia , Inibidores da Bomba de Prótons/farmacologiaRESUMO
Small-molecule compounds approved for use as drugs may be "repurposed" for new indications and studied to determine the mechanisms of their beneficial and adverse effects. A comprehensive collection of all small-molecule drugs approved for human use would be invaluable for systematic repurposing across human diseases, particularly for rare and neglected diseases, for which the cost and time required for development of a new chemical entity are often prohibitive. Previous efforts to build such a comprehensive collection have been limited by the complexities, redundancies, and semantic inconsistencies of drug naming within and among regulatory agencies worldwide; a lack of clear conceptualization of what constitutes a drug; and a lack of access to physical samples. We report here the creation of a definitive, complete, and nonredundant list of all approved molecular entities as a freely available electronic resource and a physical collection of small molecules amenable to high-throughput screening.
Assuntos
Aprovação de Drogas , Avaliação Pré-Clínica de Medicamentos , Reposicionamento de Medicamentos , Genômica , National Institutes of Health (U.S.) , Preparações Farmacêuticas , Comportamento Cooperativo , Avaliação Pré-Clínica de Medicamentos/métodos , Genômica/métodos , Humanos , Informática Médica , Preparações Farmacêuticas/química , Controle de Qualidade , Estados UnidosRESUMO
Glutathione S-transferases (GSTs) constitute a family of detoxification enzymes that catalyze the conjugation of glutathione with a variety of hydrophobic compounds, including drugs and their metabolites, to yield water-soluble derivatives that are excreted in urine or bile. Profiling the effect of small molecules on GST activity is an important component in the characterization of drug candidates and compound libraries. Additionally, specific GST isozymes have been implicated in drug resistance, especially in cancer, and thus represent potential targets for intervention. To date, there are no sensitive miniaturized high-throughput assays available for GST activity detection. A series of GST substrates containing a masked luciferin moiety have been described recently, offering the potential for configuring a sensitive screening assay via coupled luciferase reaction and standard luminescence detection. We report on the optimization and miniaturization of this homogeneous method to 1,536-well format using GSTs from 3 different species: mouse isozyme A4-4, human isozymes A1-1, M1-1, and P1-1, and the major GST from the parasitic worm Schistosoma japonicum.
Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Ensaios Enzimáticos/métodos , Glutationa Transferase/metabolismo , Preparações Farmacêuticas/metabolismo , Animais , Avaliação Pré-Clínica de Medicamentos/instrumentação , Resistência a Medicamentos , Resistencia a Medicamentos Antineoplásicos , Glutationa/metabolismo , Isoenzimas/metabolismo , Luminescência , Camundongos , Proteínas Recombinantes/metabolismo , Schistosoma japonicum/efeitos dos fármacos , Schistosoma japonicum/enzimologia , Bibliotecas de Moléculas Pequenas , Especificidade por SubstratoRESUMO
The thyroid-stimulating hormone (TSH; thyrotropin) receptor belongs to the glycoprotein hormone receptor subfamily of 7-transmembrane spanning receptors. TSH receptor (TSHR) is expressed mainly in thyroid follicular cells and is activated by TSH, which regulates the growth and function of thyroid follicular cells. Recombinant TSH is used in diagnostic screens for thyroid cancer, especially in patients after thyroid cancer surgery. Currently, no selective small-molecule agonists of the TSHR are available. To screen for novel TSHR agonists, the authors miniaturized a commercially available cell-based cyclic adenosine 3',5' monophosphate (cAMP) assay into a 1536-well plate format. This assay uses an HEK293 cell line stably transfected with the TSHR coupled to a cyclic nucleotide gated ion channel as a biosensor. From a quantitative high-throughput screen of 73,180 compounds in parallel with a parental cell line (without the TSHR), 276 primary active compounds were identified. The activities of the selected active compounds were further confirmed in an orthogonal homogeneous time-resolved fluorescence cAMP-based assay. Forty-nine compounds in several structural classes have been confirmed as the small-molecule TSHR agonists that will serve as a starting point for chemical optimization and studies of thyroid physiology in health and disease.
Assuntos
AMP Cíclico/análise , Avaliação Pré-Clínica de Medicamentos/métodos , Receptores da Tireotropina/agonistas , Bibliotecas de Moléculas Pequenas/análise , Algoritmos , Calibragem , Células Cultivadas , Reações Falso-Positivas , Humanos , Miniaturização , Modelos Biológicos , Relação Quantitativa Estrutura-Atividade , Receptores da Tireotropina/genética , TransfecçãoRESUMO
Finding specific small-molecule inhibitors of protein-protein interactions remains a significant challenge. Recently, attention has grown toward "hot spot" interactions where binding is dominated by a limited number of amino acid contacts, theoretically offering an increased opportunity for disruption by small molecules. Inhibitors of the interaction between BRCT (the C-terminal portion of BRCA1, a key tumor suppressor protein with various functions) and phosphorylated proteins (Abraxas/BACH1/CtIP), implicated in DNA damage response and repair pathways, should prove to be useful in studying BRCA1's role in cancer and in potentially sensitizing tumors to chemotherapeutic agents. We developed and miniaturized to a 1536-well format and 3-mul final volume a pair of fluorescence polarization (FP) assays using fluorescein- and rhodamine-labeled pBACH1 fragment. To minimize the effect of fluorescence artifacts and to increase the overall robustness of the screen, the 75,552 compound library members all were assayed against both the fluorescein- and rhodamine-labeled probe-protein complexes in separate but interleaved reactions. In addition, every library compound was tested over a range of concentrations following the quantitative high-throughput screening (qHTS) paradigm. Analyses of the screening results led to the selection and subsequent confirmation of 16 compounds active in both assays. Faced with a traditionally difficult protein-protein interaction assay, by performing two-fluorophore qHTS, we were able to confidently select a number of actives for further studies.
Assuntos
Proteína BRCA1/química , Proteína BRCA1/metabolismo , Avaliação Pré-Clínica de Medicamentos/métodos , Corantes Fluorescentes/metabolismo , Fosfoproteínas/metabolismo , Relação Dose-Resposta a Droga , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Concentração Inibidora 50 , Miniaturização , Preparações Farmacêuticas/química , Ligação Proteica , Bibliotecas de Moléculas PequenasRESUMO
The identification of biologically active compounds from high-throughput screening (HTS) can involve considerable postscreening analysis to verify the nature of the sample activity. In this study we evaluated the performance of micro-parallel liquid chromatography (microPLC) as a separation-based enzyme assay platform for follow-up of compound activities found in quantitative HTS of two different targets, a hydrolase and an oxidoreductase. In an effort to couple secondary analysis to primary screening we explored the application of microPLC immediately after a primary screen. In microPLC, up to 24 samples can be loaded and analyzed simultaneously via high-performance liquid chromatography within a specially designed cartridge. In a proof-of-concept experiment for screen-coupled actives verification, we identified, selected, and consolidated the contents of "active" wells from a 1,536-well format HTS experiment into a 384-well plate and subsequently analyzed these samples by a 24-channel microPLC system. The method utilized 0.6% of the original 6-microl 1,536-well assay for the analysis. The analysis revealed several non-biological-based "positive" samples. The main examples included "false" enzyme activators resulting from an increase in well fluorescence due to fluorescent compound or impurity. The microPLC analysis also provided a verification of the activity of two activators of glucocerebrosidase. We discuss the benefits of microPLC and its limitations from the standpoint of ease of use and integration into a seamless postscreen workflow.
Assuntos
Cromatografia Líquida/métodos , Avaliação Pré-Clínica de Medicamentos/métodos , Cromatografia Gasosa , Cromatografia Líquida de Alta Pressão , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos/instrumentação , Ativação Enzimática/efeitos dos fármacos , Reações Falso-Positivas , Fluorometria , Glucosilceramidase/análise , Glucosilceramidase/metabolismo , Hidroximetilglutaril-CoA Redutases/análise , Hidroximetilglutaril-CoA Redutases/metabolismo , Indicadores e Reagentes , Espectrometria de Fluorescência , Espectrofotometria UltravioletaRESUMO
INTRODUCTION: The arrhythmogenic risk of fluoxetine, citalopram, and venlafaxine were evaluated through preclinical assays measuring hERG, blood pressure and electrical alternans over their respective clinical unbound concentration ranges. METHODS: Anesthetized guinea pigs were instrumented with jugular and carotid cannulae for drug infusion and blood pressure monitoring respectively; a thoracotomy was performed for placement of a monophasic action potential probe on the left ventricle and for placement of pacing wires on the left ventricular apex. Drugs were infused as a 5-min loading dose immediately followed by a 10-min maintenance dose to achieve clinically relevant plasma concentrations; blood samples were taken at the end of each maintenance dose. Ventricular pacing was performed twice at baseline and at each dose level as follows: 50 preconditioning-beats at S1=220 (or 240) ms immediately followed by 30 test-beats at S2=200 ms. This S1-S2 protocol was repeated for S2=190 to 140 ms. HERG and calcium current measurements were recorded in HEK-293 cells stably expressing hERG potassium currents and freshly isolated guinea pig cardiac myocytes using the whole-cell configuration of the patch clamp technique. RESULTS: Physiologically relevant inhibition (IC(20)) of hERG occurred at concentrations 22-fold (fluoxetine), 9-fold (citalopram), and 11-fold (venlafaxine) beyond their respective clinically effective concentration (C(eff)). At the highest achievable levels, fluoxetine (20-fold C(eff)) and citalopram (28-fold C(eff)) significantly decreased heart rate and/or blood pressure as well as increasing electrical alternans by 5 and 18 ms respectively. Venlafaxine increased blood pressure at only 1.3-fold C(eff), but did not increase electrical alternans at the highest achievable dose (3.1-fold C(eff)). DISCUSSION: These data suggest that evaluating other dose limiting side effects in relation to a drug's therapeutic range may be crucial for accurate assessment of arrhythmia liability.