RESUMEN
Ceramides impact a diverse array of biological functions and have been implicated in disease pathogenesis. The enzyme neutral ceramidase (nCDase) is a zinc-containing hydrolase and mediates the metabolism of ceramide to sphingosine (Sph), both in cells and in the intestinal lumen. nCDase inhibitors based on substrate mimetics, for example C6-urea ceramide, have limited potency, aqueous solubility, and micelle-free fraction. To identify non-ceramide mimetic nCDase inhibitors, hit compounds from an HTS campaign were evaluated in biochemical, cell based and in silico modeling approaches. A majority of small molecule nCDase inhibitors contained pharmacophores capable of zinc interaction but retained specificity for nCDase over zinc-containing acid and alkaline ceramidases, as well as matrix metalloprotease-3 and histone deacetylase-1. nCDase inhibitors were refined by SAR, were shown to be substrate competitive and were active in cellular assays. nCDase inhibitor compounds were modeled by in silico DOCK screening and by molecular simulation. Modeling data supports zinc interaction and a similar compound binding pose with ceramide. nCDase inhibitors were identified with notably improved activity and solubility in comparison with the reference lipid-mimetic C6-urea ceramide.
Asunto(s)
Ceramidas , Ceramidasa Neutra , Dominio Catalítico , Ceramidas/química , Ceramidasa Neutra/antagonistas & inhibidores , Esfingosina/químicaRESUMEN
The severe acute respiratory syndrome coronavirus 2 responsible for COVID-19 remains a persistent threat to mankind, especially for the immunocompromised and elderly for which the vaccine may have limited effectiveness. Entry of SARS-CoV-2 requires a high affinity interaction of the viral spike protein with the cellular receptor angiotensin-converting enzyme 2. Novel mutations on the spike protein correlate with the high transmissibility of new variants of SARS-CoV-2, highlighting the need for small molecule inhibitors of virus entry into target cells. We report the identification of such inhibitors through a robust high-throughput screen testing 15,000 small molecules from unique libraries. Several leads were validated in a suite of mechanistic assays, including whole cell SARS-CoV-2 infectivity assays. The main lead compound, calpeptin, was further characterized using SARS-CoV-1 and the novel SARS-CoV-2 variant entry assays, SARS-CoV-2 protease assays and molecular docking. This study reveals calpeptin as a potent and specific inhibitor of SARS-CoV-2 and some variants.
Asunto(s)
Antivirales/farmacología , Tratamiento Farmacológico de COVID-19 , Inhibidores de Cisteína Proteinasa/farmacología , Dipéptidos/farmacología , Acoplamiento Viral/efectos de los fármacos , Internalización del Virus/efectos de los fármacos , Enzima Convertidora de Angiotensina 2/metabolismo , Animales , Catepsina L/antagonistas & inhibidores , Línea Celular , Chlorocebus aethiops , Evaluación Preclínica de Medicamentos , Reposicionamiento de Medicamentos , Células HEK293 , Humanos , Simulación del Acoplamiento Molecular , SARS-CoV-2/efectos de los fármacos , SARS-CoV-2/crecimiento & desarrollo , Serina Endopeptidasas/metabolismo , Glicoproteína de la Espiga del Coronavirus/metabolismo , Células VeroRESUMEN
α,ß-Unsaturated amides are important building blocks and are key structural elements in a number of biologically active natural products. Despite their importance and prevalence, few methods exist to prepare conjugated amides directly and modularly. To address this gap, a titanium-promoted coupling of alkynes and isocyanates has been developed. The method is highly stereoselective, producing only the E isomer with good chemoselectivity and regioselectivity (>95/5), for unsymmetrical internal alkynes that contain a steric bias. The reactive titanacyclopentene intermediate formed from the coupling of the alkyne and isocyanate was additionally reacted with various electrophiles to access tetrasubstituted enamides.
RESUMEN
Although casein kinase 1δ (CK1δ) is at the center of multiple signaling pathways, its role in the expansion of CNS progenitor cells is unknown. Using mouse cerebellar granule cell progenitors (GCPs) as a model for brain neurogenesis, we demonstrate that the loss of CK1δ or treatment of GCPs with a highly selective small molecule inhibits GCP expansion. In contrast, CK1δ overexpression increases GCP proliferation. Thus, CK1δ appears to regulate GCP neurogenesis. CK1δ is targeted for proteolysis via the anaphase-promoting complex/cyclosome (APC/C(Cdh1)) ubiquitin ligase, and conditional deletion of the APC/C(Cdh1) activator Cdh1 in cerebellar GCPs results in higher levels of CK1δ. APC/C(Cdh1) also downregulates CK1δ during cell-cycle exit. Therefore, we conclude that APC/C(Cdh1) controls CK1δ levels to balance proliferation and cell-cycle exit in the developing CNS. Similar studies in medulloblastoma cells showed that CK1δ holds promise as a therapeutic target.
Asunto(s)
Ciclosoma-Complejo Promotor de la Anafase/biosíntesis , Quinasa Idelta de la Caseína/biosíntesis , Proteínas Cdh1/biosíntesis , Sistema Nervioso Central/crecimiento & desarrollo , Neurogénesis/genética , Ciclosoma-Complejo Promotor de la Anafase/genética , Animales , Quinasa Idelta de la Caseína/genética , Proteínas Cdh1/genética , Ciclo Celular/genética , Proliferación Celular/genética , Sistema Nervioso Central/metabolismo , Cerebelo/crecimiento & desarrollo , Cerebelo/metabolismo , Regulación del Desarrollo de la Expresión Génica , Células HeLa , Humanos , Ratones , Neuronas/metabolismo , Interferencia de ARN , Transducción de SeñalRESUMEN
A modular titanium-promoted coupling of unsymmetrical internal alkynes with Weinreb amides is described. The coupling reaction takes place at room temperature and affords E-trisubstituted enones in moderate to good yields with high levels of regioselectivity. The system shows moderate chemoselectivity.
Asunto(s)
Alquinos/química , Amidas/síntesis química , Titanio/química , Amidas/química , Catálisis , Estructura Molecular , EstereoisomerismoRESUMEN
Eukaryotic mitotic entry is controlled by Cdk1, which is activated by the Cdc25 phosphatase and inhibited by Wee1 tyrosine kinase, a target of the ubiquitin proteasome pathway. Here we use a reporter of Wee1 degradation, K328M-Wee1-luciferase, to screen a kinase-directed chemical library. Hit profiling identified CK1δ-dependent Wee1 degradation. Small-molecule CK1δ inhibitors specifically disrupted Wee1 destruction and arrested HeLa cell proliferation. Pharmacological inhibition, siRNA knockdown, or conditional deletion of CK1δ also reduced Wee1 turnover. Thus, these studies define a previously unappreciated role for CK1δ in controlling the cell cycle.
Asunto(s)
Quinasa Idelta de la Caseína/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Proteolisis , Secuencia de Aminoácidos , Animales , Quinasa Idelta de la Caseína/antagonistas & inhibidores , Ciclo Celular/efectos de los fármacos , Proteínas de Ciclo Celular/química , Evaluación Preclínica de Medicamentos , Células HeLa , Humanos , Ratones , Datos de Secuencia Molecular , Proteínas Nucleares/química , Fosforilación/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Estabilidad Proteica/efectos de los fármacos , Proteínas Tirosina Quinasas/química , Proteolisis/efectos de los fármacos , Bibliotecas de Moléculas Pequeñas/farmacologíaRESUMEN
A selective iridium catalyzed hydrosilylation of alkenes in the presence of more reactive alkynes is described. By utilizing [IrCl(COD)]2 in the presence of excess COD, hydrosilylation of alkenes and alkynes with ethynylsilanes is achieved with good chemo- and regioselectivity. This approach goes against the traditional reactivity trends of platinum and rhodium catalysts and allows access to highly substituted silicon alkyne tethers.
Asunto(s)
Alquenos/química , Alquinos/química , Alquinos/síntesis química , Iridio/química , Silanos/química , Silanos/síntesis química , Catálisis , Técnicas Químicas Combinatorias , Estructura Molecular , Platino (Metal)/química , Rodio/química , EstereoisomerismoRESUMEN
The development of a series of potent and highly selective casein kinase 1δ/ε (CK1δ/ε) inhibitors is described. Starting from a purine scaffold inhibitor (SR-653234) identified by high throughput screening, we developed a series of potent and highly kinase selective inhibitors, including SR-2890 and SR-3029, which have IC50 ≤ 50 nM versus CK1δ. The two lead compounds have ≤100 nM EC50 values in MTT assays against the human A375 melanoma cell line and have physical, in vitro and in vivo PK properties suitable for use in proof of principle animal xenograft studies against human cancer cell lines.
Asunto(s)
Antineoplásicos/química , Caseína Cinasa 1 épsilon/antagonistas & inhibidores , Quinasa Idelta de la Caseína/antagonistas & inhibidores , Animales , Antineoplásicos/farmacocinética , Antineoplásicos/uso terapéutico , Sitios de Unión , Caseína Cinasa 1 épsilon/metabolismo , Quinasa Idelta de la Caseína/metabolismo , Dominio Catalítico , Línea Celular Tumoral , Supervivencia Celular , Semivida , Humanos , Ratones , Microsomas Hepáticos/metabolismo , Simulación del Acoplamiento Molecular , Neoplasias/tratamiento farmacológico , Purinas/química , Purinas/farmacocinética , Purinas/uso terapéutico , Ratas , Relación Estructura-Actividad , Trasplante HeterólogoRESUMEN
Catalytic Pd(OAc)(2) and polymethylhydrosiloxane (PMHS), in conjunction with aqueous KF, and a catalytic amount of an aromatic chloride, effects the chemo-, regio-, and stereoselective deoxygenation of benzylic oxygenated substrates at room temperature in THF. Preliminary mechanistic experiments suggest the process to involve palladium-nanoparticle-catalyzed hydrosilylation followed by C-O reduction. The chloroarene additive appears to facilitate the hydrogenolysis process through the slow controlled release of HCl.
Asunto(s)
Carbono/química , Nanopartículas/química , Oxígeno/química , Paladio/química , Siloxanos/química , Catálisis , Técnicas Químicas Combinatorias , Hidrocarburos Clorados/química , Ácido Clorhídrico/química , Estructura Molecular , Oxidación-Reducción , EstereoisomerismoRESUMEN
A rapid and high-yielding silylation of terminal alkynes employing TMSOTf and catalytic quantities of Zn(OTf)2 has been developed. The reaction works well for a variety of substrates including reactive esters. Fifteen examples with yields of >90% are reported.
Asunto(s)
Alquinos/química , Compuestos Organometálicos/química , Compuestos de Organosilicio/síntesis química , Zinc/química , Catálisis , Estructura Molecular , Compuestos de Organosilicio/química , EstereoisomerismoRESUMEN
[reaction: see text] Room-temperature reduction of aromatic nitro groups to amines can be accomplished in high yield, with wide functional group tolerance and short reaction times (30 min) using a combination of palladium(II) acetate, aqueous potassium fluoride, and polymethylhydrosiloxane (PMHS). Replacing PMHS/KF with triethylsilane allows aliphatic nitro groups to be reduced to their hydroxylamines.