Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Front Psychol ; 12: 636756, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34122229

RESUMEN

Ingratiation is a common strategy for subordinates to deal with their supervisors in eastern and western societies. Based on the theory of impression management, this study focuses on the impact of upward ingratiation outside the workplace on supervisor's human resource (HR) decisions in the Chinese context and the mechanism behind this impact. The data were collected from 252 supervisor-subordinate dyads in four manufacturing firms. The results demonstrate the following: first, supervisors hold a more favorable view of upward ingratiation outside the workplace; second, upward ingratiation outside the workplace has a positive effect on the supervisor's chance of promotion and bonus allocation decisions, and leader-member exchange (LMX) plays a mediation role in this influence; third, Zhongyong thinking (ZYT) moderates the relationship between LMX and supervisor's chance of promotion and bonus allocation decisions; and finally, ZYT moderates the indirect effect of ingratiation behavior outside the workplace on supervisor's chance of promotion and bonus allocation decisions through LMX, and the mediated relationship is weakened when a supervisor has a higher level of ZYT. This is one of the first empirical studies, which examines the validity of subordinate's upward ingratiation outside the workplace from the perspective of supervisor's ZYT. This study plays an important role in highlighting the effect of ZYT on the ingratiation behavior.

2.
MAbs ; 13(1): 1930636, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34097570

RESUMEN

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which causes coronavirus disease-2019 (COVID-19), interacts with the host cell receptor angiotensin-converting enzyme 2 (hACE2) via its spike 1 protein during infection. After the virus sequence was published, we identified two potent antibodies against the SARS-CoV-2 receptor binding domain (RBD) from antibody libraries using a phage-to-yeast (PtY) display platform in only 10 days. Our lead antibody JMB2002, now in a Phase 1 clinical trial (ChiCTR2100042150), showed broad-spectrum in vitro blocking activity against hACE2 binding to the RBD of multiple SARS-CoV-2 variants, including B.1.351 that was reportedly much more resistant to neutralization by convalescent plasma, vaccine sera and some clinical-stage neutralizing antibodies. Furthermore, JMB2002 has demonstrated complete prophylactic and potent therapeutic efficacy in a rhesus macaque disease model. Prophylactic and therapeutic countermeasure intervention of SARS-CoV-2 using JMB2002 would likely slow down the transmission of currently emerged SARS-CoV-2 variants and result in more efficient control of the COVID-19 pandemic.


Asunto(s)
Enzima Convertidora de Angiotensina 2/antagonistas & inhibidores , Anticuerpos Neutralizantes/farmacología , Antivirales/farmacología , Tratamiento Farmacológico de COVID-19 , COVID-19/prevención & control , SARS-CoV-2/efectos de los fármacos , Enzima Convertidora de Angiotensina 2/genética , Enzima Convertidora de Angiotensina 2/inmunología , Animales , Especificidad de Anticuerpos , Sitios de Unión de Anticuerpos , Células CHO , COVID-19/inmunología , COVID-19/metabolismo , COVID-19/virología , Chlorocebus aethiops , Cricetulus , Modelos Animales de Enfermedad , Epítopos , Macaca mulatta , SARS-CoV-2/inmunología , SARS-CoV-2/patogenicidad , Células Vero
3.
Front Immunol ; 11: 596908, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33329588

RESUMEN

The critical role of IgE in allergic diseases is well-documented and clinically proven. Omalizumab, a humanized anti-IgE antibody, was the first approved antibody for the treatment of allergic diseases. Nevertheless, omalizumab still has some limitations, such as product instability and dosage restriction in clinical application. In this study, we attempted to develop an omalizumab biobetter antibody with the potential to overcome its limitations. We removed two aspartic acid isomerization hotspots in CDRs of omalizumab to improve antibody candidate's stability. Meanwhile, several murine amino acids in the framework region of omalizumab were replaced with human source to reduce the potential immunogenicity. Yeast display technology was then applied to screen antibody candidates with high binding affinity to IgE. Moreover, YTE mutation in Fc fragment was introduced into the candidates for extending their serum half-life. A lead candidate, AB1904Am15, was screened out, which showed desired biophysical properties and improved stability, high binding affinity and elevated potency in vitro, prolonged half-life in human FcRn transgenic mouse, and enhanced in vivo efficacy in cynomolgus monkey asthma model. Overall, our study developed a biobetter antibody of omalizumab, AB1904Am15, which has the potential to show improved clinical benefit in the treatment of allergic diseases.


Asunto(s)
Antialérgicos/farmacología , Antialérgicos/uso terapéutico , Anticuerpos Antiidiotipos/farmacología , Anticuerpos Antiidiotipos/uso terapéutico , Hipersensibilidad/tratamiento farmacológico , Omalizumab/farmacología , Omalizumab/uso terapéutico , Antialérgicos/química , Anticuerpos Antiidiotipos/química , Afinidad de Anticuerpos/inmunología , Fenómenos Biofísicos , Cromatografía Liquida , Monitoreo de Drogas , Estabilidad de Medicamentos , Citometría de Flujo , Humanos , Hipersensibilidad/diagnóstico , Hipersensibilidad/inmunología , Inmunoglobulina E/sangre , Inmunoglobulina E/inmunología , Omalizumab/química , Unión Proteica , Espectrometría de Masas en Tándem , Resultado del Tratamiento
4.
Nat Chem Biol ; 15(2): 179-188, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30643281

RESUMEN

The identification of activating mutations in NOTCH1 in 50% of T cell acute lymphoblastic leukemia has generated interest in elucidating how these mutations contribute to oncogenic transformation and in targeting the pathway. A phenotypic screen identified compounds that interfere with trafficking of Notch and induce apoptosis via an endoplasmic reticulum (ER) stress mechanism. Target identification approaches revealed a role for SLC39A7 (ZIP7), a zinc transport family member, in governing Notch trafficking and signaling. Generation and sequencing of a compound-resistant cell line identified a V430E mutation in ZIP7 that confers transferable resistance to the compound NVS-ZP7-4. NVS-ZP7-4 altered zinc in the ER, and an analog of the compound photoaffinity labeled ZIP7 in cells, suggesting a direct interaction between the compound and ZIP7. NVS-ZP7-4 is the first reported chemical tool to probe the impact of modulating ER zinc levels and investigate ZIP7 as a novel druggable node in the Notch pathway.


Asunto(s)
Proteínas de Transporte de Catión/genética , Estrés del Retículo Endoplásmico/fisiología , Receptor Notch1/genética , Animales , Apoptosis , Proteínas Portadoras/metabolismo , Proteínas de Transporte de Catión/metabolismo , Proteínas de Transporte de Catión/fisiología , Línea Celular , Transformación Celular Neoplásica , Retículo Endoplásmico/fisiología , Humanos , Mutación , Transporte de Proteínas , Receptor Notch1/fisiología , Transducción de Señal , Zinc/metabolismo
5.
J Med Chem ; 60(6): 2215-2226, 2017 03 23.
Artículo en Inglés | MEDLINE | ID: mdl-28092155

RESUMEN

Overexpression and somatic heterozygous mutations of EZH2, the catalytic subunit of polycomb repressive complex 2 (PRC2), are associated with several tumor types. EZH2 inhibitor, EPZ-6438 (tazemetostat), demonstrated clinical efficacy in patients with acceptable safety profile as monotherapy. EED, another subunit of PRC2 complex, is essential for its histone methyltransferase activity through direct binding to trimethylated lysine 27 on histone 3 (H3K27Me3). Herein we disclose the discovery of a first-in-class potent, selective, and orally bioavailable EED inhibitor compound 43 (EED226). Guided by X-ray crystallography, compound 43 was discovered by fragmentation and regrowth of compound 7, a PRC2 HTS hit that directly binds EED. The ensuing scaffold hopping followed by multiparameter optimization led to the discovery of 43. Compound 43 induces robust and sustained tumor regression in EZH2MUT preclinical DLBCL model. For the first time we demonstrate that specific and direct inhibition of EED can be effective as an anticancer strategy.


Asunto(s)
Antineoplásicos/química , Antineoplásicos/farmacología , Complejo Represivo Polycomb 2/antagonistas & inhibidores , Sulfonas/química , Sulfonas/farmacología , Triazoles/química , Triazoles/farmacología , Animales , Antineoplásicos/farmacocinética , Antineoplásicos/uso terapéutico , Proliferación Celular/efectos de los fármacos , Cristalografía por Rayos X , Perros , Femenino , Haplorrinos , Histonas/metabolismo , Humanos , Linfoma de Células B Grandes Difuso/tratamiento farmacológico , Linfoma de Células B Grandes Difuso/metabolismo , Lisina/metabolismo , Masculino , Metilación/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Simulación del Acoplamiento Molecular , Complejo Represivo Polycomb 2/química , Complejo Represivo Polycomb 2/metabolismo , Ratas , Sulfonas/farmacocinética , Sulfonas/uso terapéutico , Triazoles/farmacocinética , Triazoles/uso terapéutico
6.
Tetrahedron ; 72(18): 2280-2286, 2016 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-29445247

RESUMEN

The de novo asymmetric total syntheses of daumone 1, daumone 3 along with 5 new analogs are described. The key steps of our approach are: the diastereoselective palladium catalyzed glycosylation reaction; the Noyori reduction of 2-acetylfuran and an ynone, which introduce the absolute stereochemistry of the sugar and aglycon portion of daumone; and an Achmatowicz rearrangement, an epoxidation and a ring opening installing the remaining asymmetry of daumone. The synthetic daumones 1 and 3 as well as related analogs were evaluated for dauer activity in C. elegans and for effects on hatching of the related nematode H. glycines. This data provides additional structure activity relationships (SAR) that further inform the study of nematode signaling.

7.
Mol Divers ; 20(2): 551-6, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26470864

RESUMEN

Bioactive tricyclic quinazolines class of 3,4-dihydro-1H-pyrimido[2,1-b]quinazolin-6(2H)-ones I and 2,3-dihydroimidazo[2,1-b]quinazolin-5(1H)-ones II were synthesized by the formic acid-catalyzed intramolecular cyclization of 3-(2-aminoalkyl)-2-(phenylamino)quinazolin-4(3H)-ones 1 in high yields. A plausible mechanism of the cyclization step is proposed.


Asunto(s)
Quinazolinonas/química , Quinazolinonas/síntesis química , Catálisis , Técnicas de Química Sintética , Ciclización
8.
Chem Commun (Camb) ; 50(46): 6137-40, 2014 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-24776538

RESUMEN

We disclose a novel efficient enantioselective organocatalytic cascade reaction for the preparation of δ-lactones in good to excellent yields (69-93%) and with high to excellent enantioselectivities (88-96% ee).


Asunto(s)
Aldehídos/química , Lactonas/síntesis química , Malonatos/química , Compuestos de Sulfhidrilo/química , Lactonas/química , Conformación Molecular , Estereoisomerismo
9.
Tetrahedron ; 69(16): 3432-3436, 2013 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-23794755

RESUMEN

An asymmetric synthesis of the di- and trisaccharide portion of the naturally occurring anthrax tetrasaccharide from acetylfuran has been developed. The construction of the di- and trisaccharide subunits is based upon our previously disclosed route to anthrax tetrasaccharide. The approach uses iterative diastereoselective palladium-catalyzed glycosylations, Luche reductions, diastereoselective dihydroxylations, and regioselective protections for the assembly of the rhamno- di- and tri-saccharide. The route was also modified for the preparation of the mixed D-/L-disaccharide analogue.

11.
Org Biomol Chem ; 10(13): 2537-41, 2012 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-22366754

RESUMEN

3,4-Dihydrocoumarins, considered to be valuable building blocks, have attracted considerable attention due to their various biological activities. Herein, we have documented an efficient and convenient double decarboxylation process for the synthesis of 4-substituted 3,4-dihydrocoumarin in moderate to excellent yields under mild reaction conditions (up to 98%).


Asunto(s)
Cumarinas/síntesis química , Productos Biológicos/química , Catálisis , Ciclización , Descarboxilación , Estructura Molecular
12.
J Am Chem Soc ; 131(43): 15642-6, 2009 Nov 04.
Artículo en Inglés | MEDLINE | ID: mdl-19807077

RESUMEN

Cr-mediated coupling reactions are usually achieved with a slight excess of a given nucleophile. To develop a cost-effective use of this process, two different approaches have been studied. The first approach depends on two consecutive catalytic asymmetric Cr-mediated couplings, with use of coupling partners purposely being of unbalanced molecular size and complexity. The second approach rests on the success in identifying the nucleophile, which allows us to achieve the coupling satisfactorily with a 1:1 molar ratio of the coupling partners. The C23-O bond is stereospecifically constructed via reductive cyclization of the oxonium ion, or oxy-Michael cyclization. Both syntheses have a high overall efficiency: E7389 C14-C35 and halichondrin C14-C38 building blocks have been synthesized from the corresponding C27-C35 and C27-C38 aldehydes, respectively, in high overall yields with an excellent stereoselectivity. Because of operational simplicity, the synthesis outlined herein appears to be well suited for scaling.


Asunto(s)
Éteres Cíclicos/síntesis química , Catálisis , Ciclización , Éteres Cíclicos/química , Espectroscopía de Resonancia Magnética , Estereoisomerismo
13.
J Am Chem Soc ; 131(43): 15636-41, 2009 Nov 04.
Artículo en Inglés | MEDLINE | ID: mdl-19807076

RESUMEN

With sequential use of catalytic asymmetric Cr-mediated coupling reactions, E7389 C14-C35 and halichondrin C14-C38 building blocks have been stereoselectively synthesized. The C19-C20 bond is first formed via the catalytic asymmetric Ni/Cr-mediated coupling, i.e., 8 + 9 --> 10 (90%; dr = 22:1), in which vinyl iodide 8 is used as the limiting substrate. The C23-C24 bond is then formed via the catalytic asymmetric Co/Cr-mediated coupling, i.e., 13 + 14 --> 4 (82%; dr = 22:1), in which the alkyl-iodide bond in 14 is selectively activated over the vinyl-iodide bond. The catalytic asymmetric Ni/Cr-mediated reaction is employed to couple C14-C26 segment 19 with E7389 C27-C35 segment 20 (91%; dr = >55:1). In this synthesis, the C23-O bond is stereoselectively constructed via a double-inversion process, i.e., 21 --> 22, to furnish E7389 C14-C35 building block 22 in 84% yield. The same synthetic sequence has been employed to synthesize halichondrin C14-C38 building block 18b, i.e., 16a + 19 --> 18b.


Asunto(s)
Éteres Cíclicos/síntesis química , Catálisis , Éteres Cíclicos/química , Níquel/química
14.
J Am Chem Soc ; 131(42): 15387-93, 2009 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-19795862

RESUMEN

Chromium catalysts derived from chiral sulfonamides represented by A effect the couplings of aldehydes with vinyl, allyl, or alkyl halides. With three distinct sites for structural modification, A affords access to a structurally diverse pool of chiral sulfonamides. The Cr catalysts derived from these sulfonamides exhibit a broad range of catalyst-substrate matching profiles. A strategy is presented to search for a satisfactory chiral sulfonamide for a given substrate. In order to demonstrate the generality and effectiveness of this approach, five diverse C-C bond-forming cases have been selected from the halichondrin synthesis. For each of the cases, two ligands have been deliberately searched for, to induce the formation of (R)- and (S)-alcohols, respectively, at the arbitrarily chosen efficiency level of ">or=80% yield with >or=20:1 stereoselectivity in the presence of

Asunto(s)
Cromo/química , Catálisis , Ligandos , Modelos Moleculares , Estructura Molecular , Estereoisomerismo , Sulfonamidas/química
15.
Org Lett ; 10(14): 3149-52, 2008 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-18549226

RESUMEN

A formal total synthesis of the oxopentaene macrolide antibiotic RK-397 has been achieved. Nine stereocenters were established by a combination of allylation and our asymmetric hydration reactions and a 1,5 anti-selective aldol reaction. The synthesis proceeded in 19 steps from simple achiral conjugated dienoates.


Asunto(s)
Antibacterianos/síntesis química , Macrólidos/síntesis química , Antibacterianos/química , Macrólidos/química , Estructura Molecular , Estereoisomerismo
16.
J Org Chem ; 73(14): 5211-20, 2008 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-18563936

RESUMEN

A de novo asymmetric approach to the natural product anthrax tetrasaccharide 1 and an analogue 2 with an anomeric hexyl azide group has been developed from acetylfuran. The construction of the tetrasaccharide was achieved by a traditional [3 + 1] glycosylation strategy. An iterative diastereoselective palladium-catalyzed glycosylation, Luche reduction, diastereoselective dihydroxylation, and regioselective acylation were employed for the assembly of the L-rhamno-trisaccharide building block. The anthrose building block also required a palladium-catalyzed azide allylation and a triflate inversion to set the gluco-stereochemistry in addition to Luche reduction and dihydroxylation.


Asunto(s)
Bacillus anthracis/química , Oligosacáridos/síntesis química , Conformación de Carbohidratos , Secuencia de Carbohidratos , Catálisis , Glicosilación , Oligosacáridos/química , Paladio/química , Estereoisomerismo
17.
ACS Chem Biol ; 3(5): 294-304, 2008 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-18376812

RESUMEN

Caenorhabditis elegans sense natural chemicals in their environment and use them as cues to regulate their development. This investigation probes the mechanism of sensory trafficking by evaluating the processing of fluorescent derivatives of natural products in C. elegans. Fluorescent analogs of daumone, an ascaroside, and apigenin were prepared by total synthesis and evaluated for their ability to induce entry into a nonaging dauer state. Fluorescent imaging detailed the uptake and localization of every labeled compound at each stage of the C. elegans life cycle. Comparative analyses against natural products that did not induce dauer indicated that dauer-triggering natural products accumulated in the cuticle of the pharnyx. Subsequent transport of these molecules to amphid neurons signaled entry into the dauer state. These studies provide cogent evidence supporting the roles of the glycosylated fatty acid daumone and related ascarosides and the ubiquitous plant flavone apigenin as chemical cues regulating C. elegans development.


Asunto(s)
Caenorhabditis elegans , Ácidos Grasos , Colorantes Fluorescentes , Faringe/metabolismo , Feromonas , Animales , Transporte Biológico , Caenorhabditis elegans/efectos de los fármacos , Caenorhabditis elegans/crecimiento & desarrollo , Caenorhabditis elegans/metabolismo , Ácidos Grasos/síntesis química , Ácidos Grasos/química , Ácidos Grasos/farmacología , Colorantes Fluorescentes/síntesis química , Colorantes Fluorescentes/química , Colorantes Fluorescentes/farmacología , Larva/efectos de los fármacos , Larva/crecimiento & desarrollo , Larva/metabolismo , Estructura Molecular , Faringe/efectos de los fármacos , Feromonas/síntesis química , Feromonas/química , Feromonas/farmacología
18.
Tetrahedron ; 64(2): 304-313, 2008 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-18283329

RESUMEN

A highly enantioselective and stereocontrolled approach to d-, l- and 8-epi-d-swainsonine has been developed from achiral furan and γ-butyrolactone. A one-pot hydrogenolysis of both azide and benzyl ether followed by an intramolecular reductive amination has been employed as key step to establish the indolizidine ring system. The absolute stereochemistry was installed by the Noyori reduction and the relative stereochemistry by the use of several highly diastereoselective palladium catalyzed glycosylation, Luche reduction, dihydroxylation and palladium catalyzed azide allylation reactions. This practical approach provide multigram quantities of indolizidine natural product d-swainsonine in 13 steps and 25% overall yield.

19.
J Org Chem ; 73(5): 1935-40, 2008 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-18237188

RESUMEN

An enantioselective and diastereocontrolled approach to 8a-epi-d-swainsonine has been developed from achiral furfural. The key step to this synthesis was a one-pot procedure for the hydrogenolytic removal of two protecting groups and two intramolecular reductive amination reactions. The absolute stereochemistry was introduced by asymmetric Noyori reduction of furfuryl ketone. This route relies on diastereoselective palladium-catalyzed glycosylation to install the anomeric bond, and Luche reduction, diastereoselective dihydroxylation to set up the manno-stereochemistry of the indolizidine precursor.


Asunto(s)
Swainsonina/síntesis química , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Espectrofotometría Infrarroja , Swainsonina/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...