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1.
Anticancer Res ; 39(8): 4111-4116, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31366495

RESUMO

BACKGROUND/AIM: We investigated whether the expression of inositol 1, 4, 5-trisphosphate receptor-binding protein released with inositol 1, 4, 5-trisphosphate (IRBIT) in clinical gastric cancer (GC) patients could predict the therapeutic response to postoperative adjuvant chemotherapy. MATERIALS AND METHODS: Immunohistochemistry was used to investigate IRBIT expression in 115 GC patients. To clarify whether IRBIT had a relationship with the therapeutic effects of chemotherapy, we compared two groups - 62 patients treated with postoperative adjuvant chemotherapy and 53 patients treated with postoperative adjuvant chemotherapy. RESULTS: Regarding the postoperative adjuvant chemotherapy-free group, we did not find any statistically significant correlation between clinicopathological features and recurrence regardless of the expression of IRBIT. In contrast, in the group receiving postoperative adjuvant chemotherapy, a significant association was found between IRBIT expression and both overall and disease-free survival. CONCLUSION: IRBIT may be used as a useful predictive marker for chemotherapy.


Assuntos
Biomarcadores Tumorais/genética , Lectinas Tipo C/genética , Proteínas de Membrana/genética , Recidiva Local de Neoplasia/tratamento farmacológico , Neoplasias Gástricas/tratamento farmacológico , Idoso , Quimioterapia Adjuvante/efeitos adversos , Intervalo Livre de Doença , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/patologia , Fosforilação/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacos , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia
2.
J Agric Food Chem ; 67(32): 8896-8904, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31339308

RESUMO

The mosquito Aedes aegypti is associated with the spread of many viral diseases in humans, including Dengue virus (DENVs), Yellow fever virus (YFV), Zika virus (ZIKV), and Chikungunya virus (CHIKV). Bacillus thuringiensis (Bt) is widely used as a biopesticide, which produces Cry toxins for mosquito control. The Cry toxins bind mainly to important receptors, including alkaline phosphatase (ALP) and aminopeptidase-N (APN). This work investigated the function of a C-type lectin, CTLGA9, in A. aegypti in response to Cry toxins. Our results showed by far-western blot and ELISA methods that the CTLTGA9 protein interacted with brush border membrane vesicles (BBMVs) of A. aegypti larvae and with ALP1, APN, and Cry11Aa proteins. Furthermore, molecular docking showed overlapping binding sites in ALP1 and APN for binding to Cry11Aa and CTLGA9. The toxicity assays further demonstrated that CTLGA9 inhibited the larvicidal activity of Cry toxins. According to the results of molecular docking, CTLGA9 may compete with Cry11Aa for binding to ALP1 and APN receptors and thus decreases the mosquitocidal toxicity of Cry11Aa. Our results provide further insights into better understanding the mechanism of Cry toxins and help improve the Cry toxicity for mosquito control.


Assuntos
Aedes/efeitos dos fármacos , Aedes/metabolismo , Proteínas de Bactérias/toxicidade , Endotoxinas/toxicidade , Proteínas Hemolisinas/toxicidade , Proteínas de Insetos/metabolismo , Aedes/química , Aedes/genética , Animais , Proteínas de Bactérias/química , Sítios de Ligação , Endotoxinas/química , Proteínas Hemolisinas/química , Proteínas de Insetos/química , Proteínas de Insetos/genética , Larva/efeitos dos fármacos , Larva/genética , Larva/metabolismo , Simulação de Acoplamento Molecular , Ligação Proteica/efeitos dos fármacos
3.
Chem Commun (Camb) ; 55(61): 8959-8962, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31290487

RESUMO

Hydrocarbon stapled peptides are promising therapeutics for inhibition of intracellular protein-protein interactions. Here we develop a new high-throughput strategy for hydrocarbon stapled peptide discovery based on mRNA display of peptides containing α-methyl cysteine and cyclized with m-dibromoxylene. We focus on development of a peptide binder to the HPV16 E2 protein.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Evolução Molecular Direcionada/métodos , Proteínas Nucleares/metabolismo , Proteínas Oncogênicas Virais/metabolismo , Peptídeos/metabolismo , Engenharia de Proteínas/métodos , Fatores de Transcrição/metabolismo , Alquilação , Sequência de Aminoácidos , Ciclização , Cisteína/química , Hidrocarbonetos Bromados/química , Biblioteca de Peptídeos , Peptídeos/química , Ligação Proteica/efeitos dos fármacos , RNA Mensageiro/química
4.
BMC Vet Res ; 15(1): 234, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31286936

RESUMO

BACKGROUND: Enterotoxigenic Escherichia coli K88 (E. coli K88) are considered as a major cause of diarrhea and death in newly weaned piglets. Oral passive immunization with chicken egg yolk immunoglobulins (IgY) have attracted considerable attention for treatment of gastrointestinal infection due to its high specificity. In this study it was estimated the protective effect of anti-K88 fimbriae IgY against E. coli K88 adhesion to piglet intestinal mucus in vitro and to investigate the potential use of IgY for controlling E. coli-induced diarrhea in weaned piglets in vivo. RESULTS: E. coli K88 was incubated with IgY for 24 h, and the bacterial growth profiles showed that specific IgY with a concentration higher than 5 mg/mL was observed to significantly inhibit the growth of E. coli K88 compared to nonspecific yolk powder in a liquid medium. Moreover, pretreatment with 50 mg/mL of IgY was found to significantly decrease the adhesion ability of E. coli K88 to porcine jejunal and ileal mucus, further supported by the observations from our immunofluorescence microscopic analysis. In vivo, administration of IgY successfully protected piglets from diarrhea caused by E. coli K88 challenge. Additionally, IgY treatment efficiently alleviated E. coli-induced intestinal inflammation in piglets as the gene expression levels of inflammatory cytokines TNF-α, IL-22, IL-6 and IL-1ß in IgY-treated piglets remained unchanged after E. coli K88 infection. Furthermore, IgY significantly prevented E. coli K88 adhering to the jejunal and ileal mucosa of piglets with E. coli infection and significantly decreased E. coli and enterotoxin expression in colonic contents. CONCLUSION: Outcome of the study demonstrated that IgY against the fimbrial antigen K88 was able to significantly inhibit the growth of E. coli K88, block the binding of E. coli to small intestinal mucus, and protect piglets from E. coli-induced diarrhea. These results indicate that passive immunization with IgY may be useful to prevent bacterial colonization and to control enteric diseases due to E. coli infection. The study has great clinical implication to provide alternative therapy to antibiotics in E coli induced diarrhea.


Assuntos
Aderência Bacteriana/efeitos dos fármacos , Diarreia/etiologia , Diarreia/prevenção & controle , Escherichia coli Enterotoxigênica/efeitos dos fármacos , Infecções por Escherichia coli/complicações , Imunoglobulinas/farmacologia , Animais , Antígenos de Bactérias/imunologia , Citocinas/genética , Diarreia/microbiologia , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/patologia , Infecções por Escherichia coli/prevenção & controle , Proteínas de Escherichia coli/imunologia , Proteínas de Fímbrias/imunologia , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/imunologia , Imunização Passiva , Imunoglobulinas/uso terapêutico , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiologia , Ligação Proteica/efeitos dos fármacos , Suínos
5.
Nat Commun ; 10(1): 2635, 2019 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-31201302

RESUMO

Multidrug efflux pumps actively expel a wide range of toxic substrates from the cell and play a major role in intrinsic and acquired drug resistance. In Gram-negative bacteria, these pumps form tripartite assemblies that span the cell envelope. However, the in situ structure and assembly mechanism of multidrug efflux pumps remain unknown. Here we report the in situ structure of the Escherichia coli AcrAB-TolC multidrug efflux pump obtained by electron cryo-tomography and subtomogram averaging. The fully assembled efflux pump is observed in a closed state under conditions of antibiotic challenge and in an open state in the presence of AcrB inhibitor. We also observe intermediate AcrAB complexes without TolC and discover that AcrA contacts the peptidoglycan layer of the periplasm. Our data point to a sequential assembly process in living bacteria, beginning with formation of the AcrAB subcomplex and suggest domains to target with efflux pump inhibitors.


Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Transporte/fisiologia , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/fisiologia , Escherichia coli/fisiologia , Lipoproteínas/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Antibacterianos/farmacologia , Proteínas de Transporte/efeitos dos fármacos , Proteínas de Transporte/ultraestrutura , Microscopia Crioeletrônica/métodos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Tomografia com Microscopia Eletrônica/métodos , Escherichia coli/efeitos dos fármacos , Escherichia coli/ultraestrutura , Proteínas de Escherichia coli/antagonistas & inibidores , Proteínas de Escherichia coli/efeitos dos fármacos , Proteínas de Escherichia coli/ultraestrutura , Microscopia Intravital/métodos , Proteínas Associadas à Resistência a Múltiplos Medicamentos/antagonistas & inibidores , Peptidoglicano/metabolismo , Periplasma/metabolismo , Ligação Proteica/efeitos dos fármacos , Estrutura Quaternária de Proteína/efeitos dos fármacos
6.
Eur J Med Chem ; 178: 13-29, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31173968

RESUMO

The oncogenic Epstein-Barr virus (EBV) evades the immune system through limiting the expression of its highly antigenic and essential genome maintenance protein, EBNA1, to the minimal level to ensure viral genome replication, thereby also minimizing the production of EBNA1-derived antigenic peptides. This regulation is based on inhibition of translation of the virally-encoded EBNA1 mRNA, and involves the interaction of host protein nucleolin (NCL) with G-quadruplex (G4) structures that form in the glycine-alanine repeat (GAr)-encoding sequence of the EBNA1 mRNA. Ligands that bind to these G4-RNA can prevent their interaction with NCL, leading to disinhibition of EBNA1 expression and antigen presentation, thereby interfering with the immune evasion of EBNA1 and therefore of EBV (M.J. Lista et al., Nature Commun., 2017, 8, 16043). In this work, we synthesized and studied a series of 20 cationic bis(acylhydrazone) derivatives designed as G4 ligands. The in vitro evaluation showed that most derivatives based on central pyridine (Py), naphthyridine (Naph) or phenanthroline (Phen) units were efficient G4 binders, in contrast to their pyrimidine (Pym) counterparts, which were poor G4 binders due to a significantly different molecular geometry. The influence of lateral heterocyclic units (N-substituted pyridinium or quinolinium residues) on G4-binding properties was also investigated. Two novel compounds, namely PyDH2 and PhenDH2, used at a 5 µM concentration, were able to significantly enhance EBNA1 expression in H1299 cells in a GAr-dependent manner, while being significantly less toxic than the prototype drug PhenDC3 (GI50 > 50 µM). Antigen presentation, RNA pull-down and proximity ligation assays confirmed that the effect of both drugs was related to the disruption of NCL-EBNA1 mRNA interaction and the subsequent promotion of GAr-restricted antigen presentation. Our work provides a novel modular scaffold for the development of G-quadruplex-targeting drugs acting through interference with G4-protein interaction.


Assuntos
Hidrazonas/farmacologia , Evasão da Resposta Imune/efeitos dos fármacos , Fatores Imunológicos/farmacologia , Fosfoproteínas/metabolismo , Ligação Proteica/efeitos dos fármacos , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Linhagem Celular Tumoral , Antígenos Nucleares do Vírus Epstein-Barr/genética , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Quadruplex G , Herpesvirus Humano 4/genética , Humanos , Hidrazonas/síntese química , Hidrazonas/química , Fatores Imunológicos/síntese química , Fatores Imunológicos/química , Ligantes , Camundongos , RNA Mensageiro/genética
7.
Eur J Med Chem ; 178: 48-63, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31176095

RESUMO

The ninety kilo Dalton molecular weight heat shock protein (Hsp90) is an attractive target for the discovery of novel anticancer agents. Several strategies have been employed for the development of inhibitors against this polypeptide. The most successful strategy is targeting the N-terminal ATP binding region of the chaperone. However, till date not a single molecule reached Phase-IV of clinical trials from this class of Hsp90 inhibitors. The other approach is to target the Cterminal region of the protein. The success with this approach has been limited due to lack of well-defined ligand binding pocket in this terminal. The other promising strategy is to prevent the interaction of client proteins/co-chaperones with Hsp90 protein, i.e., protein-protein interaction inhibitors of Hsp90. The review focuses on advantage of this approach along with the recent advances in the discovery of inhibitors by following this strategy. Additionally, the biology of the client protein/co-chaperone binding site of Hsp90 is also discussed.


Assuntos
Antineoplásicos/uso terapêutico , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Proteínas de Choque Térmico HSP90/metabolismo , Neoplasias/tratamento farmacológico , Ligação Proteica/efeitos dos fármacos , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Sítios de Ligação , Linhagem Celular Tumoral , Proteínas de Choque Térmico HSP90/química , Humanos
8.
Eur J Med Chem ; 178: 214-231, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31185412

RESUMO

Discovery of antimicrobial agents with a novel model of action is in urgent need for the clinical management of multidrug-resistant bacterial infections. Recently, we reported the identification of a first-in-class bacterial ribosomal RNA synthesis inhibitor, which interrupted the interaction between the bacterial transcription factor NusB and NusE. In this study, a series of diaryl derivatives were rationally designed and synthesized based on the previously established pharmacophore model. Inhibitory activity against the NusB-NusE binding, circular dichroism of compound treated NusB, antimicrobial activity, cytotoxicity, hemolytic property and cell permeability using Caco-2 cells were measured. Structure-activity relationship and quantitative structure-activity relationship were also concluded and discussed. Some of the derivatives demonstrated improved antimicrobial activity than the hit compound against a panel of clinically important pathogens, lowering the minimum inhibition concentration to 1-2 µg/mL against Staphylococcus aureus, including clinical strains of methicillin-resistant Staphylococcus aureus at a level comparable to some of the marketed antibiotics. Given the improved antimicrobial activity, specific inhibition of target protein-protein interaction and promising pharmacokinetic properties without significant cytotoxicity, this series of diaryl compounds have high potentials and deserve for further studies towards a new class of antimicrobial agents in the future.


Assuntos
Compostos de Anilina/farmacologia , Antibacterianos/farmacologia , Benzilaminas/farmacologia , Ligação Proteica/efeitos dos fármacos , Bases de Schiff/farmacologia , Compostos de Anilina/síntese química , Compostos de Anilina/química , Compostos de Anilina/toxicidade , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/toxicidade , Proteínas de Bactérias/metabolismo , Benzilaminas/síntese química , Benzilaminas/química , Benzilaminas/toxicidade , Células CACO-2 , Desenho de Drogas , Eritrócitos/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Células HeLa , Hemólise/efeitos dos fármacos , Humanos , Queratinócitos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Bases de Schiff/síntese química , Bases de Schiff/química , Bases de Schiff/toxicidade , Relação Estrutura-Atividade , Fatores de Transcrição/metabolismo
9.
J Enzyme Inhib Med Chem ; 34(1): 1152-1157, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31179771

RESUMO

Nine indole derivatives (9a-i) were tested as potential inhibitors of the Keap1-Nrf2 interaction. This class of compounds increases the intracellular levels of the transcription factor Nrf2 and the consequent expression of enzymes encoded by genes containing the antioxidant response element (ARE). In the ARE-luciferase reporter assay only 9e-g revealed to be remarkably more active than t-butylhydroxyquinone (t-BHQ), with 9g standing out as the best performing compound. While 9e and 9f are weak acids, 9g is an ampholyte prevailing as a zwitterion in neutral aqueous solutions. The ability of 9e-g to significantly increase levels of Nrf2, NADPH:quinone oxidoreductase 1, and transketolase (TKT) gave further support to the hypothesis that these compounds act as inhibitors of the Keap1-Nrf2 interaction. Docking simulations allowed us to elucidate the nature of the putative interactions between 9g and Keap1.


Assuntos
Indóis/química , Indóis/farmacologia , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Relação Dose-Resposta a Droga , Células HeLa , Humanos , Modelos Moleculares , Estrutura Molecular , Ligação Proteica/efeitos dos fármacos , Relação Estrutura-Atividade
10.
Nat Commun ; 10(1): 2607, 2019 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-31197133

RESUMO

Inhibiting the RAS oncogenic protein has largely been through targeting the switch regions that interact with signalling effector proteins. Here, we report designed ankyrin repeat proteins (DARPins) macromolecules that specifically inhibit the KRAS isoform by binding to an allosteric site encompassing the region around KRAS-specific residue histidine 95 at the helix α3/loop 7/helix α4 interface. We show that these DARPins specifically inhibit KRAS/effector interactions and the dependent downstream signalling pathways in cancer cells. Binding by the DARPins at that region influences KRAS/effector interactions in different ways, including KRAS nucleotide exchange and inhibiting KRAS dimerization at the plasma membrane. These results highlight the importance of targeting the α3/loop 7/α4 interface, a previously untargeted site in RAS, for specifically inhibiting KRAS function.


Assuntos
Sítio Alostérico/efeitos dos fármacos , Antineoplásicos/farmacologia , Desenho de Drogas , Neoplasias/tratamento farmacológico , Proteínas Proto-Oncogênicas p21(ras)/antagonistas & inibidores , Repetição de Anquirina , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Células HEK293 , Histidina/metabolismo , Humanos , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Isoenzimas/metabolismo , Neoplasias/genética , Neoplasias/patologia , Biblioteca de Peptídeos , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/genética , Multimerização Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transdução de Sinais/efeitos dos fármacos
11.
Nat Commun ; 10(1): 2572, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31189917

RESUMO

Activation of G-protein coupled receptors elevates cAMP levels promoting dissociation of protein kinase A (PKA) holoenzymes and release of catalytic subunits (PKAc). This results in PKAc-mediated phosphorylation of compartmentalized substrates that control central aspects of cell physiology. The mechanism of PKAc activation and signaling have been largely characterized. However, the modes of PKAc inactivation by regulated proteolysis were unknown. Here, we identify a regulatory mechanism that precisely tunes PKAc stability and downstream signaling. Following agonist stimulation, the recruitment of the chaperone-bound E3 ligase CHIP promotes ubiquitylation and proteolysis of PKAc, thus attenuating cAMP signaling. Genetic inactivation of CHIP or pharmacological inhibition of HSP70 enhances PKAc signaling and sustains hippocampal long-term potentiation. Interestingly, primary fibroblasts from autosomal recessive spinocerebellar ataxia 16 (SCAR16) patients carrying germline inactivating mutations of CHIP show a dramatic dysregulation of PKA signaling. This suggests the existence of a negative feedback mechanism for restricting hormonally controlled PKA activities.


Assuntos
Subunidades Catalíticas da Proteína Quinase Dependente de AMP Cíclico/metabolismo , AMP Cíclico/metabolismo , Retroalimentação Fisiológica/fisiologia , Chaperonas Moleculares/metabolismo , Ataxias Espinocerebelares/patologia , Animais , Retroalimentação Fisiológica/efeitos dos fármacos , Fibroblastos , Células HEK293 , Proteínas de Choque Térmico HSP70/antagonistas & inibidores , Hipocampo/patologia , Holoenzimas/metabolismo , Humanos , Leupeptinas/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação , Cultura Primária de Células , Ligação Proteica/efeitos dos fármacos , Proteólise/efeitos dos fármacos , Nucleosídeos de Purina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Ataxias Espinocerebelares/genética , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação/fisiologia
12.
Nat Commun ; 10(1): 2746, 2019 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-31227712

RESUMO

Nicotinic acetylcholine receptors (nAChRs) mediate and modulate synaptic transmission throughout the brain, and contribute to learning, memory, and behavior. Dysregulation of α7-type nAChRs in neuropsychiatric as well as immunological and oncological diseases makes them attractive targets for pharmaceutical development. Recently, we identified NACHO as an essential chaperone for α7 nAChRs. Leveraging the robust recombinant expression of α7 nAChRs with NACHO, we utilized genome-wide cDNA library screening and discovered that several anti-apoptotic Bcl-2 family proteins further upregulate receptor assembly and cell surface expression. These effects are mediated by an intracellular motif on α7 that resembles the BH3 binding domain of pro-apoptotic Bcl-2 proteins, and can be blocked by BH3 mimetic Bcl-2 inhibitors. Overexpression of Bcl-2 member Mcl-1 in neurons enhanced surface expression of endogenous α7 nAChRs, while a combination of chemotherapeutic Bcl2-inhibitors suppressed neuronal α7 receptor assembly. These results demonstrate that Bcl-2 proteins link α7 nAChR assembly to cell survival pathways.


Assuntos
Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Neurônios/metabolismo , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Motivos de Aminoácidos/genética , Animais , Benzotiazóis/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Células HEK293 , Humanos , Isoquinolinas/farmacologia , Chaperonas Moleculares/metabolismo , Mutação , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Neurônios/efeitos dos fármacos , Agonistas Nicotínicos/farmacologia , Cultura Primária de Células , Ligação Proteica/efeitos dos fármacos , Piridinas/farmacologia , Pirimidinas/farmacologia , Ratos , Transmissão Sináptica/efeitos dos fármacos , Tiofenos/farmacologia , Regulação para Cima , Receptor Nicotínico de Acetilcolina alfa7/genética
13.
Nat Commun ; 10(1): 2765, 2019 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-31235691

RESUMO

G protein-coupled receptors (GPCRs) can integrate extracellular signals via allosteric interactions within dimers and higher-order oligomers. However, the structural bases of these interactions remain unclear. Here, we use the GABAB receptor heterodimer as a model as it forms large complexes in the brain. It is subjected to genetic mutations mainly affecting transmembrane 6 (TM6) and involved in human diseases. By cross-linking, we identify the transmembrane interfaces involved in GABAB1-GABAB2, as well as GABAB1-GABAB1 interactions. Our data are consistent with an oligomer made of a row of GABAB1. We bring evidence that agonist activation induces a concerted rearrangement of the various interfaces. While the GB1-GB2 interface is proposed to involve TM5 in the inactive state, cross-linking of TM6s lead to constitutive activity. These data bring insight for our understanding of the allosteric interaction between GPCRs within oligomers.


Assuntos
Modelos Moleculares , Domínios Proteicos/fisiologia , Multimerização Proteica/fisiologia , Receptores de GABA-B/metabolismo , Regulação Alostérica/efeitos dos fármacos , Regulação Alostérica/fisiologia , Sítio Alostérico/efeitos dos fármacos , Sítio Alostérico/fisiologia , Reagentes para Ligações Cruzadas/química , Agonistas dos Receptores de GABA-B/farmacologia , Células HEK293 , Humanos , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/fisiologia , Domínios Proteicos/efeitos dos fármacos , Multimerização Proteica/efeitos dos fármacos , Ácido gama-Aminobutírico/metabolismo
14.
Eur J Med Chem ; 177: 414-424, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31158754

RESUMO

Due to the role of butyrylcholinesterase (BChE) in acetylcholine hydrolysis in the late stages of the Alzheimer's disease (AD), inhibitors of butyrylcholinesterase (BChE) have been recently envisaged, besides acetylcholinesterase (AChE) inhibitors, as candidates for treating mild-to-moderate AD. Herein, synthesis and AChE/BChE inhibition activity of some twenty derivatives of 1,2,3,4,5,6-hexahydroazepino[4,3-b]indole (HHAI) is reported. Most of the newly synthesized HHAI derivatives achieved the inhibition of both ChE isoforms with IC50s in the micromolar range, with a structure-dependent selectivity toward BChE. Apparently, molecular volume and lipophilicity do increase selectivity toward BChE, and indeed the N2-(4-phenylbutyl) HHAI derivative 15d, which behaves as a mixed-type inhibitor, resulted the most potent (IC50 0.17 µM) and selective (>100-fold) inhibitor toward either horse serum and human BChE. Moreover, 15d inhibited in vitro self-induced aggregation of neurotoxic amyloid-ß (Aß) peptide and displayed neuroprotective effects in neuroblastoma SH-SY5Y cell line, significantly recovering (P < 0.001) cell viability when impaired by Aß1-42 and hydrogen peroxide insults. Overall, this study highlighted HHAI as useful and versatile scaffold for developing new small molecules targeting some enzymes and biochemical pathways involved in the pathogenesis of AD.


Assuntos
Azepinas/farmacologia , Inibidores da Colinesterase/farmacologia , Indóis/farmacologia , Fármacos Neuroprotetores/farmacologia , Peptídeos beta-Amiloides/metabolismo , Azepinas/síntese química , Azepinas/química , Azepinas/metabolismo , Butirilcolinesterase/química , Butirilcolinesterase/metabolismo , Domínio Catalítico , Linhagem Celular Tumoral , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/química , Inibidores da Colinesterase/metabolismo , Relação Dose-Resposta a Droga , Desenho de Drogas , Depuradores de Radicais Livres/síntese química , Depuradores de Radicais Livres/química , Depuradores de Radicais Livres/metabolismo , Depuradores de Radicais Livres/farmacologia , Humanos , Indóis/síntese química , Indóis/química , Indóis/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Fármacos Neuroprotetores/síntese química , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/metabolismo , Fragmentos de Peptídeos/metabolismo , Ligação Proteica/efeitos dos fármacos , Multimerização Proteica/efeitos dos fármacos , Relação Estrutura-Atividade
15.
Eur J Med Chem ; 177: 448-456, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31174062

RESUMO

The colchicine site inhibitors (CSIs) showed promising prospects as antitumor agents due to their vascular disrupting activities besides antimitotic activities. 1-Phenyl-dihydrobenzoindazole was found as a novel scaffold of CSI without the cis-trans isomerization problem. The X-ray co-crystal structure of the lead compound with tubulin was determined, which revealed the binding mode including special water-bridged hydrogen bonds. The structure also provided guidance for the structural optimization of this type of CSI, which led to the discovery of the most potent inhibitor A3, with growth IC50 lower than 1 nM against human colon cancer cell lines and tubulin polymerization IC50 of 1.6 µM. In addition, its water-soluble prodrug B1 showed good in vivo antitumor activity on two human colon cancer xenograft nude mice models, encouraging further study of this type of antitumor compound.


Assuntos
Antineoplásicos/farmacologia , Sítios de Ligação/efeitos dos fármacos , Indazóis/farmacologia , Moduladores de Tubulina/farmacologia , Tubulina (Proteína)/metabolismo , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/metabolismo , Feminino , Células HCT116 , Humanos , Indazóis/síntese química , Indazóis/química , Indazóis/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Nus , Estrutura Molecular , Pró-Fármacos/síntese química , Pró-Fármacos/química , Pró-Fármacos/metabolismo , Pró-Fármacos/farmacologia , Ligação Proteica/efeitos dos fármacos , Solubilidade , Tubulina (Proteína)/química , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/química , Moduladores de Tubulina/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
16.
Phys Chem Chem Phys ; 21(27): 14957-14963, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31236551

RESUMO

Heme, as the cofactor and active site of Hb, enables Hb to carry out the necessary function required for O2 management for life, that is, reversible O2 binding for transport. In this paper, the microscopic mechanism of heme-associated poisoning has been elucidated from the perspective of electronic interaction by performing first-principles calculations. The results show that the functional groups (-CHO, -COOH, -NO2, -NH2) and CN exhibit a stronger affinity for heme than O2 and are more likely to occupy the O2 binding site, which results in the loss of the ability of heme to carry O2. Moreover, the addition of functional groups, CO and CN to heme at the side site can cause a pronounced enhancement toward the O2 binding characteristics of heme, which prevents heme from releasing O2 to oxygen-consuming tissues as the blood circulates. The reversible O2 binding function of heme is disrupted by the presence of these toxic ligands in the heme binding pocket, which greatly affects O2 transport in the blood. The inability of tissues to obtain O2 leads to tissue hypoxia, which is the main cause of poisoning. Based on the energy, geometry and electronic properties, the hypoxia mechanism proposed by us coincides well with experiment, and the research has the potential to provide a theoretical reference for the relevant areas of bioscience.


Assuntos
Heme/metabolismo , Ligantes , Oxigênio/metabolismo , Hipóxia Celular/efeitos dos fármacos , Heme/química , Ligação Proteica/efeitos dos fármacos , Toxinas Biológicas/metabolismo , Toxinas Biológicas/toxicidade
17.
Phys Chem Chem Phys ; 21(27): 15120-15132, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31241637

RESUMO

The concept of chirality has become prominent over the years, particularly with regards to the design of therapeutic molecules. This phenomenon was recently reported for pro-carcinogenic fibroblast growth factor receptor 1 (FGFR1), wherein two inhibitors exhibited disparate inhibitory potencies due to the effects of chirality. Therefore, the ability of the R-enantiomer (R-21c) to possess a potency 10.44 times that of the S-enantiomer (S-21c) leaves us with a curiosity to investigate the underlying mechanisms using computational methods. Hence, presented in this study are insights that clearly explain the systematic effects of chirality on the differential activities of (R)-21c and (S)-21c towards FGFR1. The findings showed that the "R-configured" (R)-21c induced a notable conformational change in the active site P-loop, which enhanced its motion, as complemented by rotation of two dihedral angles: φ1(CNCC) and φ2(CC*OC), providing a favorable orientation. Likewise, optimal positioning of (R)-21c at the binding cavity allowed adequate interspaces that facilitated the formation of strong interactions with target residues. Moreover, the estimated ΔG binding correlated with bioactivity data (IC50) and, when decomposed, we observed that van der Waals (vdW) interactions were the major highlight of the binding process of both 21c enantiomers and also accounted for their differential activities. Active site interactions of (R)-21c with residues Phe489 and Arg629 stabilized its two benzimidazole motifs, while Arg570 and Pro663 formed two strong NH-N hydrogen bonds and one π-alkyl interaction, which altogether accounted for its inhibitory prowess towards FGFR1. In contrast, these interactions were not observed in (S)-21c due to its non-flexible S-configuration, which disallowed its extension into the active site region and prevented interaction with crucial residues. These results are expected to facilitate the discovery and rational design of novel and specific FGFR1 inhibitors.


Assuntos
Indazóis/química , Indazóis/farmacologia , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismo , Concentração Inibidora 50 , Ligação Proteica/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia
18.
Eur J Med Chem ; 174: 265-276, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31051401

RESUMO

On the basis of the hybridization strategy of natural products, a total of 32 novel celastrol hybrids were designed, synthesized and evaluated for their antitumor activities. Most of these derivatives exihibited significant antiproliferative activities compared to celastrol, among which compound 29 displayed the strongest inhibitory capability [IC50 = 0.15 ±â€¯0.03 µM (A549),0.17 ±â€¯0.03 µM (MCF-7), 0.26 ±â€¯0.02 µM (HepG2)], which exhibited equal or superior anti-cancer activities in comparison to 2-cyano-3,12-dioxoolean-1,9 (11)-dien-28-oic acid methyl ester (CDDO-Me). The mechanism of pharmacological research indicated that 29 possessed the ability to disrupt Hsp90-Cdc37 complex which was stronger than celastrol. Meanwhile, compound 29 could induce abnormal regulation of clients (p-Akt and Cdk4) of Hsp90 and cell cycle arrest at G0/G1 phase in a concentration-dependent manner. In addition, compound 29 could also induce cell apoptosis through the death receptor pathway on A549 cells. Taken together, our results demonstrated that 29 might be a promising novel candidate for further druggability research.


Assuntos
Antineoplásicos/farmacologia , Triterpenos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Chaperoninas/metabolismo , Desenho de Drogas , Ensaios de Seleção de Medicamentos Antitumorais , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Estrutura Molecular , Ligação Proteica/efeitos dos fármacos , Relação Estrutura-Atividade , Triterpenos/síntese química , Triterpenos/química
19.
Mar Drugs ; 17(5)2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31126085

RESUMO

Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels that are involved in fast synaptic transmission and mediated physiological activities in the nervous system. α-Conotoxin ImI exhibits subtype-specific blockade towards homomeric α7 and α9 receptors. In this study, we established a method to build a 2×ImI-dendrimer/h (human) α7 nAChR model, and based on this model, we systematically investigated the molecular interactions between the 2×ImI-dendrimer and hα7 nAChR. Our results suggest that the 2×ImI-dendrimer possessed much stronger potency towards hα7 nAChR than the α-ImI monomer and demonstrated that the linker between α-ImI contributed to the potency of the 2×ImI-dendrimer by forming a stable hydrogen-bond network with hα7 nAChR. Overall, this study provides novel insights into the binding mechanism of α-ImI dendrimer to hα7 nAChR, and the methodology reported here opens an avenue for the design of more selective dendrimers with potential usage as drug/gene carriers, macromolecular drugs, and molecular probes.


Assuntos
Simulação por Computador , Conotoxinas/farmacologia , Dendrímeros/farmacologia , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Humanos , Ligação Proteica/efeitos dos fármacos
20.
Mar Drugs ; 17(5)2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31137661

RESUMO

Pinnatoxins (PnTXs) A-H constitute an emerging family belonging to the cyclic imine group of phycotoxins. Interest has been focused on these fast-acting and highly-potent toxins because they are widely found in contaminated shellfish. Despite their highly complex molecular structure, PnTXs have been chemically synthetized and demonstrated to act on various nicotinic acetylcholine receptor (nAChR) subtypes. In the present work, PnTX-A, PnTX-G and analogue, obtained by chemical synthesis with a high degree of purity (>98%), have been studied in vivo and in vitro on adult mouse and isolated nerve-muscle preparations expressing the mature muscle-type (α1)2ß1δε nAChR. The results show that PnTX-A and G acted on the neuromuscular system of anesthetized mice and blocked the compound muscle action potential (CMAP) in a dose- and time-dependent manner, using a minimally invasive electrophysiological method. The CMAP block produced by both toxins in vivo was reversible within 6-8 h. PnTX-A and G, applied to isolated extensor digitorum longus nerve-muscle preparations, blocked reversibly isometric twitches evoked by nerve stimulation. The action of PnTX-A was reversed by 3,4-diaminopyridine. Both toxins exerted no direct action on muscle fibers, as revealed by direct muscle stimulation. PnTX-A and G blocked synaptic transmission at mouse neuromuscular junctions and PnTX-A amino ketone analogue (containing an open form of the imine ring) had no effect on neuromuscular transmission. These results indicate the importance of the cyclic imine for interacting with the adult mammalian muscle-type nAChR. Modeling and docking studies revealed molecular determinants responsible for the interaction of PnTXs with the muscle-type nAChR.


Assuntos
Alcaloides/farmacologia , Músculo Esquelético/efeitos dos fármacos , Compostos de Espiro/farmacologia , Esteróis/farmacologia , Transmissão Sináptica/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Alcaloides/síntese química , Animais , Feminino , Masculino , Camundongos , Bloqueadores Neuromusculares/síntese química , Bloqueadores Neuromusculares/farmacologia , Antagonistas Nicotínicos/síntese química , Antagonistas Nicotínicos/farmacologia , Ligação Proteica/efeitos dos fármacos , Receptores Nicotínicos/metabolismo , Compostos de Espiro/síntese química , Esteróis/síntese química
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