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1.
Adv Exp Med Biol ; 1131: 371-394, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31646518

RESUMO

Ca2+ signals are probably the most common intracellular signaling cellular events, controlling an extensive range of responses in virtually all cells. Many cellular stimuli, often acting at cell surface receptors, evoke Ca2+ signals by mobilizing Ca2+ from intracellular stores. Inositol trisphosphate (IP3) was the first messenger shown to link events at the plasma membrane to release Ca2+ from the endoplasmic reticulum (ER), through the activation of IP3-gated Ca2+ release channels (IP3 receptors). Subsequently, two additional Ca2+ mobilizing messengers were discovered, cADPR and NAADP. Both are metabolites of pyridine nucleotides, and may be produced by the same class of enzymes, ADP-ribosyl cyclases, such as CD38. Whilst cADPR mobilizes Ca2+ from the ER by activation of ryanodine receptors (RyRs), NAADP releases Ca2+ from acidic stores by a mechanism involving the activation of two pore channels (TPCs). In addition, other pyridine nucleotides have emerged as intracellular messengers. ADP-ribose and 2'-deoxy-ADPR both activate TRPM2 channels which are expressed at the plasma membrane and in lysosomes.


Assuntos
Cálcio , ADP-Ribose Cíclica , Piridinas , Animais , Cálcio/metabolismo , Sinalização do Cálcio , Retículo Endoplasmático/metabolismo , Humanos , Espaço Intracelular/metabolismo , NADP/metabolismo , Piridinas/química , Piridinas/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo
2.
Bioresour Technol ; 291: 121866, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31374417

RESUMO

The study was to explore the feasibility of polyurethane (PU), Fe3O4@PU, powdered activated carbon (PAC), Fe(OH)3@PAC, biochar, and Fe(OH)3@biochar as biological carriers in strengthening anaerobic degradation of quinoline, pyridine, and indole. When the concentrations of pollutants were 25 mg/L and 50 mg/L, reactors based on PAC and Fe(OH)3@PAC had higher degradation ratios than the other reactors. However, when the concentrations of pollutants were 75 mg/L and 100 mg/L, with the addition of PU and Fe3O4@PU, reactors began to show their superiority in the degradation of the selected NHCs. Among these, the reactor based on Fe3O4@PU had the optimal degradation ratio on quinoline, pyridine, and indole. PU, PAC, Fe(OH)3@PAC, biochar, and Fe(OH)3@biochar benefited the enrichment of Acinetobacter, Comamonas, Levilinea, Longilinea, and Desulfomicrobium. The reactor with the carrier of Fe3O4@PU had some specificity, which benefited the enrichment of Zoogloea, Thiobacillus, Anaeromyxobacter, Sphingobium, Terrimonas, Parcubacteria genera incertae sedis, Bdellovibrio, Rhizobium, and Acidovorax.


Assuntos
Carvão Vegetal/metabolismo , Compostos Férricos/química , Indóis/metabolismo , Poliuretanos/química , Piridinas/metabolismo , Quinolinas/metabolismo , Anaerobiose
3.
Environ Pollut ; 252(Pt B): 1593-1598, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31279977

RESUMO

Exploring traditional neonicotinoid pesticides substitutes has become one of the global scientific attentions because of their hazardous environmental impacts. Cycloxaprid (CYC) is considered to be a promising candidate alternative. But the environmental behaviors and fate of CYC in different planting system remain poorly understood. The accumulation of 14C-labeled CYC stereoisomers within different parts of Chinese cabbage (Brassica chinensis L.) was investigated, with a particular focus on the foliar absorption, translocation and stereoselectivity of CYC, during a laboratory trial. In general, the stereoisomers 14C-5R,8S-CYC and 14C-5S,8R-CYC, their metabolites, as well as the breakdown and reaction products can be transferred in both acropetal and basipetal directions. Most of the two stereoisomers absorbed by plants remained in the treated leaves, whereas a small amount was distributed to the roots. The amount of 14C in the stalks varied among the experimental time points. At 192 h after treatment (HAT), the detected radioactivity of both 14C-5R,8S-CYC and 14C-5S,8R-CYC in the leaves above the treated leaf (LATL) was higher than that in the leaves below the treated leaf (LBTL). However, the stereoisomers of CYC underwent nonstereoselective absorption and translocation in this trial. This information implies that racemic CYC and its metabolites should be a main research focus. Thus, the obtained results provide implications for a more accurate prediction about the risk assessment of CYC, which will be helpful for guiding its rational use as well as securing the ecological environment safety and human health.


Assuntos
Brassica/metabolismo , Compostos Heterocíclicos com 3 Anéis/metabolismo , Inseticidas/metabolismo , Neonicotinoides/metabolismo , Folhas de Planta/metabolismo , Piridinas/metabolismo , Transporte Biológico , Compostos Heterocíclicos com 3 Anéis/química , Inseticidas/química , Modelos Teóricos , Neonicotinoides/química , Raízes de Plantas/metabolismo , Piridinas/química , Estereoisomerismo
4.
Eur J Med Chem ; 177: 316-337, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31158747

RESUMO

Residues in the histone substrate binding sites that differ between the KDM4 and KDM5 subfamilies were identified. Subsequently, a C8-substituted pyrido[3,4-d]pyrimidin-4(3H)-one series was designed to rationally exploit these residue differences between the histone substrate binding sites in order to improve affinity for the KDM4-subfamily over KDM5-subfamily enzymes. In particular, residues E169 and V313 (KDM4A numbering) were targeted. Additionally, conformational restriction of the flexible pyridopyrimidinone C8-substituent was investigated. These approaches yielded potent and cell-penetrant dual KDM4/5-subfamily inhibitors including 19a (KDM4A and KDM5B Ki = 0.004 and 0.007 µM, respectively). Compound cellular profiling in two orthogonal target engagement assays revealed a significant reduction from biochemical to cell-based activity across multiple analogues; this decrease was shown to be consistent with 2OG competition, and suggests that sub-nanomolar biochemical potency will be required with C8-substituted pyrido[3,4-d]pyrimidin-4(3H)-one compounds to achieve sub-micromolar target inhibition in cells.


Assuntos
Inibidores Enzimáticos/farmacologia , Histona Desmetilases com o Domínio Jumonji/antagonistas & inibidores , Piridinas/farmacologia , Pirimidinonas/farmacologia , Linhagem Celular Tumoral , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Humanos , Interações Hidrofóbicas e Hidrofílicas , Histona Desmetilases com o Domínio Jumonji/química , Histona Desmetilases com o Domínio Jumonji/metabolismo , Estrutura Molecular , Ligação Proteica , Piridinas/síntese química , Piridinas/química , Piridinas/metabolismo , Pirimidinonas/síntese química , Pirimidinonas/química , Pirimidinonas/metabolismo , Relação Estrutura-Atividade
5.
Eur J Med Chem ; 178: 168-176, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31181481

RESUMO

The androgen receptor (AR) is a steroid hormone receptor and its high expression and disruption of its regulation are strongly implicated in prostate cancer (PCa) development. One of the current therapies includes application of steroidal antiandrogens leading to blockade of the AR action by the abrogation of AR-mediated signaling. We introduced here novel 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused steroidal compounds, described their synthesis based on [8π+2π] cycloaddition reactions of diazafulvenium methides with different steroidal scaffolds and showed their biological evaluation in different prostate cancer cell lines in vitro. Our results showed the ability of novel compounds to suppress the expression of known androgen receptor targets, Nkx3.1 and PSA in two prostate cell lines, 22Rv1 and VCaP. Candidate compound diminished the transcription of AR-regulated genes in the reporter cell line in a concentration-dependent manner. Antiproliferative activity of the most promising steroid was studied by clonogenic assay and induction of apoptosis in treated cells was documented by immunoblot detection of cleaved PARP.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Próstata/tratamento farmacológico , Pirazóis/farmacologia , Piridinas/farmacologia , Esteroides/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/metabolismo , Sítios de Ligação , Linhagem Celular Tumoral , Proteínas de Homeodomínio/metabolismo , Humanos , Masculino , Simulação de Acoplamento Molecular , Pirazóis/síntese química , Pirazóis/metabolismo , Piridinas/síntese química , Piridinas/metabolismo , Receptores Androgênicos/metabolismo , Esteroides/síntese química , Esteroides/metabolismo , Fatores de Transcrição/metabolismo
6.
J Agric Food Chem ; 67(26): 7223-7231, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31180671

RESUMO

The aim of this study was to investigate the effect of 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid (PCA), a metabolite of the fungicide fluopyram, on grapevine. During spring and summer 2015, grapevine growth disorders were observed in several countries in Europe. An unprecedented herbicide-like damage was diagnosed on leaves and flowers, causing significant loss of harvest. This study proposes PCA as the causing agent of the observed growth disorders. PCA was shown to cause leaf epinasty, impaired berry development that leads to crop loss, and root growth anomalies in Vitis vinifera similar to auxin herbicides in a dose-dependent manner. Using both field trials and greenhouse experiments, the present study provides first evidence for a link between the application of fluopyram in vineyards 2014, the formation of PCA, and the emergence of growth anomalies in 2015. Our data could be useful to optimize dosage, application time point, and other conditions for an application of fluopyram without phytotoxic effects.


Assuntos
Benzamidas/metabolismo , Ácidos Carboxílicos/efeitos adversos , Fungicidas Industriais/efeitos adversos , Piridinas/efeitos adversos , Piridinas/metabolismo , Vitis/efeitos dos fármacos , Vitis/crescimento & desenvolvimento , Benzamidas/efeitos adversos , Ácidos Carboxílicos/metabolismo , Flores/efeitos dos fármacos , Flores/crescimento & desenvolvimento , Flores/metabolismo , Frutas/efeitos dos fármacos , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Fungicidas Industriais/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Vitis/metabolismo
7.
Molecules ; 24(9)2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31052478

RESUMO

The synaptic vesicle protein 2 (SV2) is involved in synaptic vesicle trafficking. The SV2A isoform is the most studied and its implication in epilepsy therapy led to the development of the first SV2A PET radiotracer [18F]UCB-H. The objective of this study was to evaluate in vivo, using microPET in rats, the specificity of [18F]UCB-H for SV2 isoform A in comparison with the other two isoforms (B and C) through a blocking assay. Twenty Sprague Dawley rats were pre-treated either with the vehicle, or with specific competitors against SV2A (levetiracetam), SV2B (UCB5203) and SV2C (UCB0949). The distribution volume (Vt, Logan plot, t* 15 min) was obtained with a population-based input function. The Vt analysis for the entire brain showed statistically significant differences between the levetiracetam group and the other groups (p < 0.001), but also between the vehicle and the SV2B group (p < 0.05). An in-depth Vt analysis conducted for eight relevant brain structures confirmed the statistically significant differences between the levetiracetam group and the other groups (p < 0.001) and highlighted the superior and the inferior colliculi along with the cortex as regions also displaying statistically significant differences between the vehicle and SV2B groups (p < 0.05). These results emphasize the in vivo specificity of [18F]UCB-H for SV2A against SV2B and SV2C, confirming that [18F]UCB-H is a suitable radiotracer for in vivo imaging of the SV2A proteins with PET.


Assuntos
Encéfalo/diagnóstico por imagem , Glicoproteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Piridinas/metabolismo , Pirrolidinonas/metabolismo , Animais , Encéfalo/metabolismo , Levetiracetam/administração & dosagem , Levetiracetam/farmacologia , Imagem por Ressonância Magnética , Masculino , Modelos Animais , Estrutura Molecular , Tomografia por Emissão de Pósitrons , Piridinas/química , Pirrolidinonas/química , Ratos , Ratos Sprague-Dawley , Sensibilidade e Especificidade
8.
J Mol Model ; 25(6): 172, 2019 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-31129727

RESUMO

The potential of hydroxypyridinones for in vivo iron sequestration, in both biological and medical contexts, has been extensively discussed in the literature. Different chelators can be designed, with distinct lipophilicities that should alter their cell permeability, distribution, and rates of metabolism. However, for effective iron scavenging in biological systems, the redox potential and binding affinity of iron must fall within a proper range. Our objective was to assess the impact of different hydroxypyridinone chelators in 3:1 iron(III) complexes through comparison of these thermodynamic properties. For that purpose, we employed a cluster-continuum approach using density functional theory, on a dataset of 25 iron complexes. Whenever possible, our results were compared with experimental stability constants (log ß) and with electrode potentials. We observed a good qualitative agreement between computed free energies of binding and log ß values. In addition, we described which substitutions to the 3-hydroxypyridin-4-one ring should not markedly affect the redox properties and metal ion affinity considering iron. Graphical abstract Iron complexes of hydroxypyridinones.


Assuntos
Ferro/química , Modelos Moleculares , Piridinas/química , Algoritmos , Teoria da Densidade Funcional , Interações Hidrofóbicas e Hidrofílicas , Ferro/metabolismo , Ligantes , Conformação Molecular , Estrutura Molecular , Oxirredução , Piridinas/metabolismo
9.
J Plant Res ; 132(4): 531-540, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31127431

RESUMO

Areca nuts (seeds of Areca catechu L.) are a traditional and popular masticatory in India, Bangladesh, Malaysia, certain parts of China, and some other countries. Four related pyridine alkaloids (arecoline, arecaidine, guvacoline, and guvacine) are considered being the main functional ingredients in areca nut. Until now, A. catechu is the only known species producing these alkaloids in the Arecaceae family. In the present study, we investigated alkaloid contents in 12 Arecaceae species and found that only Areca triandra Roxb. contained these pyridine alkaloids. We further analyzed in more detail tissue-specific and development-related distribution of these alkaloids in leaves, male and female flowers and fruits in different stages of maturity in A. triandra by ultra-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry. Results revealed that the alkaloids were most abundant in young leaves, the pericarp of ripe fruits and the endosperm of unripe fruits in developmental stage 2. Abundance of the 4 different alkaloids in A. triandra fruits varied during maturation. Pericarps of ripe fruits had the highest arecaidine concentration (4.45 mg g-1) and the lowest guvacoline concentration (0.0175 mg g-1), whereas the endosperm of unripe fruits of developmental stage 2 contained the highest guvacoline concentration (3.39 mg g-1) and the lowest guvacine concentration (0.245 mg g-1). We conclude that A. triandra is useful in future as a further valuable source of Areca alkaloids.


Assuntos
Alcaloides/metabolismo , Areca/metabolismo , Areca/crescimento & desenvolvimento , Arecolina/análogos & derivados , Arecolina/metabolismo , Cromatografia Líquida de Alta Pressão , Flores/metabolismo , Frutas/metabolismo , Espectrometria de Massas , Ácidos Nicotínicos/metabolismo , Folhas de Planta/metabolismo , Piridinas/metabolismo
10.
Eur J Med Chem ; 176: 410-418, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31125895

RESUMO

Positron emission tomography (PET) imaging of the 18 kDa translocator protein (TSPO), has a high diagnostic potential in neurodegenerative disorders and cancer. However, TSPO is considered a challenge for molecular imaging due to the poor availability of suitable radiotracers with adequate pharmacokinetic properties. Here, we describe the development of a radiofluorinated pyridinyl isoquinoline analogue of the established TSPO PET tracer (R)-[11C]PK11195 with improved binding properties in all known human TSPO phenotypes. We conducted a complete preclinical evaluation using in vitro, in vivo and ex vivo methods to assess the performance of this novel radiotracer and observed high specific binding of the radiotracer to TSPO, as well as high metabolic stability. Therefore, we propose this radiolabeled compound for further evaluation in animal models as well as in clinical trials.


Assuntos
Isoquinolinas/metabolismo , Piridinas/metabolismo , Compostos Radiofarmacêuticos/metabolismo , Receptores de GABA/metabolismo , Animais , Feminino , Radioisótopos de Flúor/química , Humanos , Isoquinolinas/síntese química , Isoquinolinas/química , Isoquinolinas/farmacocinética , Marcação por Isótopo , Camundongos Endogâmicos C57BL , Microssomos Hepáticos/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Piridinas/síntese química , Piridinas/química , Piridinas/farmacocinética , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/farmacocinética , Distribuição Tecidual
11.
MBio ; 10(2)2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30890610

RESUMO

The biosynthesis of antioxidant pigments, namely, betalains, was believed to be restricted to Caryophyllales plants. This paper changes this paradigm, and enzyme mining from bacterial hosts promoted the discovery of bacterial cultures producing betalains. The spectrum of possible sources of betalain pigments in nature is broadened by our description of the first betalain-forming bacterium, Gluconacetobacter diazotrophicus The enzyme-specific step is the extradiol cleavage of the precursor amino acid l-dihydroxyphenylalanine (l-DOPA) to form the structural unit betalamic acid. Molecular and functional work conducted led to the characterization of a novel dioxygenase, a polypeptide of 17.8 kDa with a Km of 1.36 mM, with higher activity and affinity than those of its plant counterparts. Its superior activity allowed the first experimental characterization of the early steps in the biosynthesis of betalains by fully characterizing the presence and time evolution of 2,3- and 4,5-seco-DOPA intermediates. Furthermore, spontaneous chemical reactions are characterized and incorporated into a comprehensive enzymatic-chemical mechanism that yields the final pigments.IMPORTANCE Several studies have demonstrated the health-promoting effects of betalains due to their high antioxidant capacity and their positive effect on the dose-dependent inhibition of cancer cells and their proliferation. To date, betalains were restricted to plants of the order Caryophyllales and some species of fungi, but the present study reveals the first betalain-producing bacterium, as well as the first steps in the formation of pigments. This finding demonstrates that betalain biosynthesis can be expanded to prokaryotes.


Assuntos
Betalaínas/metabolismo , Corantes/metabolismo , Gluconacetobacter/metabolismo , Pigmentos Biológicos/metabolismo , Dioxigenases/química , Dioxigenases/genética , Dioxigenases/metabolismo , Gluconacetobacter/enzimologia , Gluconacetobacter/genética , Levodopa/metabolismo , Redes e Vias Metabólicas , Peso Molecular , Pigmentação , Piridinas/metabolismo
12.
Anal Bioanal Chem ; 411(11): 2383-2394, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30820631

RESUMO

Solid-phase microextraction (SPME) is an alternative method to dialysis and ultrafiltration for the determination of plasma protein binding (PPB) of drugs. It is particularly advantageous for complicated analytes where standard methods are not applicable. Di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) is a lead compound of novel thiosemicarbazone anti-cancer drugs, which entered clinical trials in 2016. However, this agent exhibited non-specific binding on filtration membranes and had intrinsic chelation activity, which precluded standard PPB methods. In this study, using a simple and fast procedure, we prepared novel SPME fibers for extraction of DpC based on a metal-free, silicon string support, covered with C18 sorbent. Reproducibility of the preparation process was demonstrated by the percent relative standard deviation (RSD) of ≤ 9.2% of the amount of DpC extracted from PBS by several independently prepared fibers. The SPME procedure was optimized by evaluating extraction and desorption time profiles. Suitability of the optimized protocol was verified by examining reproducibility, linearity, and recovery of DpC extracted from PBS or plasma. All samples extracted by SPME were analyzed using an optimized and validated UHPLC-MS/MS method. The developed procedure was applied to the in vitro determination of PPB of DpC at two clinically relevant concentrations (500 and 1000 ng/mL). These studies showed that DpC is highly bound to plasma proteins (PPB ≥ 88%) and this did not differ significantly between both concentrations tested. This investigation provides novel data in the applicability of SPME for the determination of PPB of chelators, as well as useful information for the clinical development of DpC. Graphical abstract.


Assuntos
Antineoplásicos/metabolismo , Proteínas Sanguíneas/metabolismo , Piridinas/metabolismo , Microextração em Fase Sólida/instrumentação , Tiossemicarbazonas/metabolismo , Adsorção , Animais , Bovinos , Cromatografia Líquida de Alta Pressão/métodos , Desenho de Equipamento , Ligação Proteica , Ratos , Silício/química , Microextração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos
13.
Comput Biol Chem ; 80: 54-65, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30901601

RESUMO

Development of novel, safe and effective drug candidates combating the emerging drug resistance has remained a major focus in the mainstream of anti-tuberculosis research. Here, we inspired to design and synthesize series of new pyridin-4-yl-1,3,4-oxadiazol-2-yl-thio-ethylidene-hydrazinecarbothioamide derivatives as potential anti-tubercular agents. The anti-tubercular bioactive assay demonstrated that the synthesized compounds exhibit potent anti-tubercular activity (MIC = 3.9-7.81 µg/mL) in comparison with reference drugs Rifampicin and Isoniazid.We employed pharmacophore probing approach for the identification of CYP51 as a possible drug target for the synthesized compounds. To understand the preferable binding mode, the synthesized molecules were docked onto the active site of Sterol 14 α-demethylases (CYP51) target. From the binding free energy of the docking results it was revealed that the compounds were effective CYP51 inhibitors and acts as antitubercular agent.


Assuntos
Antituberculosos/farmacologia , Oxidiazóis/farmacologia , Piridinas/farmacologia , Tiossemicarbazonas/farmacologia , Antituberculosos/síntese química , Antituberculosos/química , Antituberculosos/metabolismo , Domínio Catalítico , Família 51 do Citocromo P450/química , Família 51 do Citocromo P450/metabolismo , Desenho de Drogas , Depuradores de Radicais Livres/síntese química , Depuradores de Radicais Livres/química , Depuradores de Radicais Livres/metabolismo , Depuradores de Radicais Livres/farmacologia , Isoniazida/farmacologia , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Oxidiazóis/síntese química , Oxidiazóis/química , Oxidiazóis/metabolismo , Ligação Proteica , Piridinas/síntese química , Piridinas/química , Piridinas/metabolismo , Rifampina/farmacologia , Relação Estrutura-Atividade , Tiossemicarbazonas/síntese química , Tiossemicarbazonas/química , Tiossemicarbazonas/metabolismo
14.
Nat Commun ; 10(1): 184, 2019 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-30643149

RESUMO

Sulfonamide is present in many important drugs, due to its unique chemical and biological properties. In contrast, naturally occurring sulfonamides are rare, and their biosynthetic knowledge are scarce. Here we identify the biosynthetic gene cluster of sulfonamide antibiotics, altemicidin, SB-203207, and SB-203208, from Streptomyces sp. NCIMB40513. The heterologous gene expression and biochemical analyses reveal unique aminoacyl transfer reactions, including the tRNA synthetase-like enzyme SbzA-catalyzed L-isoleucine transfer and the GNAT enzyme SbzC-catalyzed ß-methylphenylalanine transfer. Furthermore, we elucidate the biogenesis of 2-sulfamoylacetic acid from L-cysteine, by the collaboration of the cupin dioxygenase SbzM and the aldehyde dehydrogenase SbzJ. Remarkably, SbzM catalyzes the two-step oxidation and decarboxylation of L-cysteine, and the subsequent intramolecular amino group rearrangement leads to N-S bond formation. This detailed analysis of the aminoacyl sulfonamide antibiotics biosynthetic machineries paves the way toward investigations of sulfonamide biosynthesis and its engineering.


Assuntos
Aminoaciltransferases/metabolismo , Vias Biossintéticas/genética , Indenos/metabolismo , Família Multigênica , Streptomyces/metabolismo , Sulfonamidas/metabolismo , Alcaloides/metabolismo , Aminoaciltransferases/genética , Isoleucina/metabolismo , Piridinas/metabolismo , Streptomyces/genética , Compostos de Enxofre/metabolismo
15.
Med Sci Monit ; 25: 77-86, 2019 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-30605443

RESUMO

BACKGROUND Palbociclib, a specific inhibitor of CDK4/6, has been shown to provide a survival benefit in hormone receptor-positive advanced breast cancer; however, its resistance and related mechanisms are unclear. MATERIAL AND METHODS In this study, we constructed palbociclib-resistant hormone receptor-positive breast cancer cells (MCF-7-P) via culturing with palbociclib for at least 6 months. Quantitative real-time PCR (qRT-PCR) and western blot were used to detect the expression of stemness markers in MCF-7-P and MCF-7 cells. Additionally, cell spheroid formation, Transwell migration, ALDH1 activity, and flow cytometry assays were performed to detect stemness and migration ability of MCF-7-P cells, and the effects of everolimus on MCF-7-P cells stemness and migration ability. Growth inhibition assay was used to examine the effect of everolimus on the sensitivity of palbociclib in MCF-7-P and MCF-7 cells. RESULTS MCF-7-P cells had stronger stemness and higher expression of ABCG2 and MDR1. Moreover, PI3K/Akt/mTOR signaling was hyper-activated in MCF-7-P cells. Additionally, everolimus, which is a mTOR inhibitor, attenuated MCF-7-P cells stemness and re-sensitized MCF-7-P cells to palbociclib. Importantly, everolimus enhanced the antitumor effect of palbociclib in palbociclib-sensitive hormone receptor-positive cells (MCF-7 cells). CONCLUSIONS These findings provide a rationale for future clinical trials of palbociclib and everolimus combination-based therapy in hormone receptor-positive breast cancer.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Everolimo/farmacologia , Piperazinas/metabolismo , Piridinas/metabolismo , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , China , Resistencia a Medicamentos Antineoplásicos/fisiologia , Feminino , Humanos , Células MCF-7 , Fosfatidilinositol 3-Quinase/metabolismo , Piperazinas/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Piridinas/farmacologia , Receptores Estrogênicos/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo
16.
J Mol Model ; 25(1): 13, 2019 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-30607513

RESUMO

The c-Met D1228V/H/N mutation clinically causes acquired resistance to type I tyrosine kinase inhibitors (TKIs), while maintaining sensitivity to type II TKIs in targeted gastric cancer therapy. The mutation is located in the activation loop (A-loop) region of the c-Met kinase domain, which substitutes the negatively charged residue Asp1228 with electroneutral amino acid Val, His, or Asn, thus electrostatically destabilizing the DFG-in conformation of A-loop and inducing its transition to DFG-out state. The transition is spontaneous in a dynamics point of view and the A-loop exhibits a large intrinsic disorder during the transitional dynamics course. In DFG-in conformation, the wild-type Asp1228 is surrounded by a number of positively charged residues within its first and second shells, which can also form a hydrogen-bonding network with its vicinal residues Phe1089, Lys1110, Asp1222, and Met1229 in the first shell. Type I and type II TKIs respond oppositely to the mutation; the former shows a generic resistance to the mutation, whereas the latter is generally sensitized by the mutation. Both types of TKIs do not directly interact with the mutation. Instead, the mutation-induced conformational change in A-loop reshapes kinase active site and then influences the site interactions with inhibitor ligands, thus conferring different selectivity to the type I and type II TKIs. Graphical abstract The molecular mechanism of D1228V/H/N mutation-induced inhibitor resistance and sensitivity in c-Met kinase is investigated. The mutation electrostatically destabilizes the DFG-in conformation of kinase A-loop and induces its spontaneous transition to DFG-out state, which reshapes kinase active site and influences the site interactions with inhibitor ligands.


Assuntos
Resistencia a Medicamentos Antineoplásicos/genética , Mutação , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas c-met/genética , Neoplasias Gástricas/tratamento farmacológico , Anilidas/química , Anilidas/metabolismo , Anilidas/uso terapêutico , Sítios de Ligação , Humanos , Simulação de Dinâmica Molecular , Estrutura Molecular , Terapia de Alvo Molecular/métodos , Ligação Proteica , Conformação Proteica , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas c-met/química , Proteínas Proto-Oncogênicas c-met/metabolismo , Pirazinas/química , Pirazinas/metabolismo , Pirazinas/uso terapêutico , Piridinas/química , Piridinas/metabolismo , Piridinas/uso terapêutico , Eletricidade Estática , Triazinas/química , Triazinas/metabolismo , Triazinas/uso terapêutico
17.
Ann Neurol ; 85(2): 218-228, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30597619

RESUMO

OBJECTIVE: Surgical specimens from patients with mesial temporal lobe epilepsy (MTLE) show abnormalities in tissue concentrations of metabotropic glutamate receptor type 5 (mGluR5). To clarify whether these abnormalities are specific to the epileptogenic zone (EZ), we characterized in vivo whole-brain mGluR5 availability in MTLE patients using positron emission tomography (PET) and [11 C]ABP688, a radioligand that binds specifically to the mGluR5 allosteric site. METHODS: Thirty-one unilateral MTLE patients and 30 healthy controls underwent [11 C]ABP688 PET. We compared partial volume corrected [11 C]ABP688 nondisplaceable binding potentials (BPND ) between groups using region-of-interest and whole-brain voxelwise analyses. [18 F]Fluorodeoxyglucose (FDG) PET was acquired in 15 patients, for whom we calculated asymmetry indices of [11 C]ABP688 BPND and [18 F]FDG uptake to compare lateralization and localization differences. RESULTS: [11 C]ABP688 BPND was focally reduced in the epileptogenic hippocampal head and amygdala (p < 0.001). Patients with hippocampal atrophy showed more extensive abnormalities, including the ipsilateral temporal neocortex (p = 0.006). [11 C]ABP688 BPND showed interhemispheric differences of higher magnitude and discriminated the epileptogenic structures more accurately when compared to [18 F]FDG uptake, which showed more widespread hypometabolism. Among 23 of 25 operated patients with >1 year of follow-up, 13 were seizure-free (Engel Ia) and showed significantly lower [11 C]ABP688 BPND in the ipsilateral entorhinal cortex. INTERPRETATION: [11 C]ABP688 PET provides a focal biomarker for the EZ in MTLE with higher spatial accuracy compared to [18 F]FDG PET. Focally reduced mGluR5 availability in the EZ might reflect receptor internalization or conformational changes in response to excessive extracellular glutamate, supporting a potential role for mGluR5 as therapeutic target in human MTLE. Ann Neurol 2019; 1-11 ANN NEUROL 2019;85:218-228.


Assuntos
Epilepsia do Lobo Temporal/diagnóstico por imagem , Epilepsia do Lobo Temporal/metabolismo , Receptor de Glutamato Metabotrópico 5/metabolismo , Adolescente , Adulto , Idoso , Radioisótopos de Carbono/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oximas/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Piridinas/metabolismo , Adulto Jovem
18.
Cell Mol Life Sci ; 76(6): 1151-1167, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30600358

RESUMO

Neuronal nicotinic receptors containing α4 and ß2 subunits assemble in two pentameric stoichiometries, (α4)3(ß2)2 and (α4)2(ß2)3, each with distinct pharmacological signatures; (α4)3(ß2)2 receptors are strongly potentiated by the drug NS9283, whereas (α4)2(ß2)3 receptors are unaffected. Despite this stoichiometry-selective pharmacology, the molecular identity of the target for NS9283 remains elusive. Here, studying (α4)3(ß2)2 receptors, we show that mutations at either the principal face of the ß2 subunit or the complementary face of the α4 subunit prevent NS9283 potentiation of ACh-elicited single-channel currents, suggesting the drug targets the ß2-α4 pseudo-agonist sites, the α4-α4 agonist site, or both sites. To distinguish among these possibilities, we generated concatemeric receptors with mutations at specified subunit interfaces, and monitored the ability of NS9283 to potentiate ACh-elicited single-channel currents. We find that a mutation at the principal face of the ß2 subunit at either ß2-α4 pseudo-agonist site suppresses potentiation, whereas mutation at the complementary face of the α4 subunit at the α4-α4 agonist site allows a significant potentiation. Thus, monitoring potentiation of single concatemeric receptor channels reveals that the ß2-α4 pseudo-agonist sites are required for stoichiometry-selective drug action. Together with the recently determined structure of the (α4)3(ß2)2 receptor, the findings have implications for structure-guided drug design.


Assuntos
Neurônios/fisiologia , Agonistas Nicotínicos/metabolismo , Receptores Nicotínicos/metabolismo , Acetilcolina/metabolismo , Acetilcolina/farmacologia , Potenciais de Ação/efeitos dos fármacos , Sítios de Ligação/genética , Sinergismo Farmacológico , Células HEK293 , Humanos , Modelos Moleculares , Mutação , Neurônios/metabolismo , Agonistas Nicotínicos/farmacologia , Oxidiazóis/metabolismo , Oxidiazóis/farmacologia , Conformação Proteica , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Subunidades Proteicas/química , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Piridinas/metabolismo , Piridinas/farmacologia , Receptores Nicotínicos/química , Receptores Nicotínicos/genética
19.
Transl Psychiatry ; 9(1): 5, 2019 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-30664620

RESUMO

Alterations of the 5-HT1A receptor and BDNF have consistently been associated with affective disorders. Two functional single nucleotide polymorphisms (SNPs), rs6295 of the serotonin 1A receptor gene (HTR1A) and rs6265 of brain-derived neurotrophic factor gene (BDNF), may impact transcriptional regulation and expression of the 5-HT1A receptor. Here we investigated interaction effects of rs6295 and rs6265 on 5-HT1A receptor binding. Forty-six healthy subjects were scanned with PET using the radioligand [carbonyl-11C]WAY-100635. Genotyping was performed for rs6265 and rs6295. Subjects showing a genotype with at least three risk alleles (G of rs6295 or A of rs6265) were compared to control genotypes. Cortical surface binding potential (BPND) was computed for 32 cortical regions of interest (ROI). Mixed model was applied to study main and interaction effects of ROI and genotype. ANOVA was used for post hoc analyses. Individuals with the risk genotypes exhibited an increase in 5-HT1A receptor binding by an average of 17% (mean BPND 3.56 ± 0.74 vs. 2.96 ± 0.88). Mixed model produced an interaction effect of ROI and genotype on BPND and differences could be demonstrated in 10 ROI post hoc. The combination of disadvantageous allelic expression of rs6295 and rs6265 may result in a 5-HT1A receptor profile comparable to affective disorders as increased 5-HT1A receptor binding is a well published phenotype of depression. Thus, epistasis between BDNF and HTR1A may contribute to the multifactorial risk for affective disorders and our results strongly advocate further research on this genetic signature in affective disorders.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Encéfalo/metabolismo , Transtorno Depressivo/genética , Epistasia Genética , Receptor 5-HT1A de Serotonina/metabolismo , Adulto , Alelos , Encéfalo/diagnóstico por imagem , Fator Neurotrófico Derivado do Encéfalo/genética , Estudos Transversais , Feminino , Genótipo , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Piperazinas/metabolismo , Polimorfismo de Nucleotídeo Único , Tomografia por Emissão de Pósitrons , Piridinas/metabolismo , Receptor 5-HT1A de Serotonina/genética
20.
J Med Chem ; 62(2): 928-940, 2019 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-30563338

RESUMO

The availability of a chemical probe to study the role of a specific domain of a protein in a concentration- and time-dependent manner is of high value. Herein, we report the identification of a highly potent and selective ERK5 inhibitor BAY-885 by high-throughput screening and subsequent structure-based optimization. ERK5 is a key integrator of cellular signal transduction, and it has been shown to play a role in various cellular processes such as proliferation, differentiation, apoptosis, and cell survival. We could demonstrate that inhibition of ERK5 kinase and transcriptional activity with a small molecule did not translate into antiproliferative activity in different relevant cell models, which is in contrast to the results obtained by RNAi technology.


Assuntos
Proteína Quinase 7 Ativada por Mitógeno/antagonistas & inibidores , Inibidores de Proteínas Quinases/química , Piridinas/química , Pirimidinas/química , Apoptose/efeitos dos fármacos , Sítios de Ligação , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Avaliação Pré-Clínica de Medicamentos , Meia-Vida , Humanos , Proteína Quinase 7 Ativada por Mitógeno/metabolismo , Simulação de Acoplamento Molecular , Inibidores de Proteínas Quinases/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Estrutura Terciária de Proteína , Piridinas/metabolismo , Piridinas/farmacologia , Pirimidinas/metabolismo , Pirimidinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-Atividade , Transcrição Genética/efeitos dos fármacos
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