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BACKGROUND: With the exacerbating effects of the global climate change and the more and more attention to the study of plant carbon sink, an increasing number of researches on plant carbon sinks has grown. Although many studies exist on shrub vegetation, soil and litters, most studies focus on the community structure, biomass, surface soil of single plant and shrub layer vegetation, and lack the studies which included the potential relationships between climate change and ecological stoichiometric elements, comprehensive research on main species, even herb and litter layer. In order to provide relevant theoretical basis and data support, it is necessary to take the main terrestrial shrub ecosystem in Central Yunnan as the starting point to analyze and explore its carbon sink distribution characteristics, formation causes, the correlation between climatic factors (temperature and precipitation) and stoichiometric elements, which from community and species levels. METHODS: Plants which originated from 12 main shrub species, litter and soil samples which collected in 69 plots were from 23 plots (Q1-Q23) of 11 cities (countries) in the central Yunnan, China. The biomass and carbon density distribution pattern of each shrub ecosystem and the potential correlations with main climate factors was explored and identified. Some indexes were analyzed such as biomass and carbon density of each part of the shrub ecosystem distribution pattern, correlation, significant changes, formation reasons with the mean value (±standard deviation: SD). Through the redundancy analysis(RDA) of carbon (c), nitrogen (n), phosphorus (P) and main climate factors (precipitation and temperature), the distribution pattern of stoichiometric elements in shrub ecosystem can be judged. RESULTS: (1) The above-ground biomass (AGB), under-ground biomass (UGB) and root-shoot ratio (R/S) were between 1.13-2.03 t/hm2, 0.62-1.49 t/hm2, and 0.38-0.84, the carbon element was distributed in herb layer under-ground part and rhizomes of the shrub layer mostly. (2) The fitting slope of AGB and UGB of shrub communities and species was in accordance with the allometric distribution growth relationship, the R/S of shrubs was smaller than other vegetation types. Mean annual temperature (MAT) and mean annual precipitation (MAP) are not the main factors which affect the biomass and R/S. (3) The contents of C, N and P elements in leaves were significantly higher than other parts in shrub layer. P in shrub layer above-ground part is much higher than under-ground part. The surface soil layer has the highest C content, and decreased with the depth, so as the impact of vegetation and litter on the content of soil elements. Both of the correlation of MAT with N content of leaf, C/N of stem, the correlation of MAP with C content, C/N of soil is the greatest.
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Ecossistema , Plantas , Biomassa , China , Carbono/análise , Fósforo/análise , SoloRESUMO
A series of novel (R)-6,6a,7,8,9,10-hexahydro-5H-pyrazino[1,2-a][1,n]naphthyridines were identified as potent and selective agonists of the 5-HT2C receptor. Optimizations performed on a previously reported series of racemic tetrahydroquinoline-based tricyclic amines, delivered an advanced drug lead, (R)-4-(3,3,3-trifluoropropyl)-6,6a,7,8,9,10-hexahydro-5H-pyrazino[1,2-a][1,8]naphthyridine, which displayed excellent in vitro and in vivo pharmacological profiles.
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Receptor 5-HT2C de Serotonina/metabolismo , Agonistas do Receptor 5-HT2 de Serotonina/farmacologia , Animais , Relação Dose-Resposta a Droga , Humanos , Microssomos Hepáticos/química , Microssomos Hepáticos/metabolismo , Estrutura Molecular , Ratos , Agonistas do Receptor 5-HT2 de Serotonina/síntese química , Agonistas do Receptor 5-HT2 de Serotonina/química , Relação Estrutura-AtividadeRESUMO
This study aimed to evaluate the effects and explore the mechanisms of polyethylene (PE), polyurethane sponge (PUS), and granule activated carbon (GAC) on short-chain fatty acids (SCFAs) production from sludge anaerobic fermentation. Results showed that no matter the biocarrier type, addition of biocarriers increased the diversity of SCFAs. In contrast with GAC, addition of PE and PUS considerably facilitated the accumulation of the total SCFAs. Suspended PE and PUS might have stronger frictions with sludge particles which resulted in a better sludge disintegration. Other factors that contributed to the enhancement of PE and PUS include higher hydrolytic and acidogenic enzymes activities, lower methanogenic enzyme activity, more Firmicutes and less Proteobacteria. Consistent with enzymatic and microbial results, the PE and the PUS tests also showed greater abundance in all metabolic functions predicted with PICRUSt. This study provides a novel strategy for sludge anaerobic fermentation by using traditional wastewater biocarriers.
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Ácidos Graxos Voláteis , Esgotos , Anaerobiose , Fermentação , Concentração de Íons de Hidrogênio , HidróliseRESUMO
A series of potential new 5-HT2 receptor scaffolds based on a simplification of the clinically studied, 5-HT2CR agonist vabicaserin, were designed. An in vivo feeding assay early in our screening process played an instrumental part in the lead identification process, leading us to focus on a 6,5,7-tricyclic scaffold. A subsequent early SAR investigation provided potent agonists of the 5-HT2C receptor that were highly selective in both functional and binding assays, had good rat PK properties and that significantly reduced acute food intake in the rat.
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Benzodiazepinas/farmacologia , Compostos Heterocíclicos com 3 Anéis/farmacologia , Receptor 5-HT2C de Serotonina/metabolismo , Agonistas do Receptor 5-HT2 de Serotonina/farmacologia , Animais , Benzodiazepinas/síntese química , Benzodiazepinas/metabolismo , Benzodiazepinas/farmacocinética , Cães , Descoberta de Drogas , Estabilidade de Medicamentos , Compostos Heterocíclicos com 3 Anéis/síntese química , Compostos Heterocíclicos com 3 Anéis/metabolismo , Compostos Heterocíclicos com 3 Anéis/farmacocinética , Humanos , Macaca fascicularis , Masculino , Camundongos , Microssomos/metabolismo , Estrutura Molecular , Ratos Sprague-Dawley , Agonistas do Receptor 5-HT2 de Serotonina/síntese química , Agonistas do Receptor 5-HT2 de Serotonina/metabolismo , Agonistas do Receptor 5-HT2 de Serotonina/farmacocinética , Relação Estrutura-AtividadeRESUMO
Chrysin is a natural flavone that has various biological activities, including antitumor effects. However, the effect of chrysin on bladder cancer cells remains elusive. The present study investigated the effects of chrysin on bladder cancer cells and its underlying mechanisms. The results demonstrated that chrysin induced apoptosis via the intrinsic pathway, as evidenced by activation of caspase-9 and caspase-3, however not caspase-8. In addition, chrysin reduced the expression of anti-apoptotic B cell lymphoma (Bcl) proteins including Bcl-2, Mcl-1, Bcl-xl, and promoted the protein expression of pro-apoptotic Bcl-2 associated X, apoptosis regulator. Chrysin also induced endoplasmic reticulum stress via activation of the unfolded protein response of PRKR-like endoplasmic reticulum kinase, eIF2α and activating transcription factor 4 in bladder cancer cells. Additionally, chrysin inhibited the signal transducer and activator of transcription 3 pathway. Furthermore, the generation of reactive oxygen species (ROS) was detected following treatment with chrysin. The ROS scavenger N-acetylcysteine inhibited the antitumor effect of chrysin. Collectively, these results indicate chrysin may act as a promising therapeutic candidate for targeting bladder cancer.
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The discovery of a novel, selective and fully efficacious CB2 agonist with satisfactory pharmacokinetic and pharmaceutical properties is described. Compound 6 was efficacious in a rat model of osteoarthritis pain following oral administration and, in contrast to morphine, maintained its analgesic effect throughout a 5-day subchronic treatment paradigm. These data were consistent with our hypothesis that full agonist efficacy is required for efficient internalization and recycling of the CB2 receptor to avoid tachyphylaxis. Based on its overall favorable preclinical profile, 6 (APD371) was selected for further development for the treatment of pain.
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BACKGROUND: Nearly 30% of clear cell renal cell carcinoma (ccRCC) patients present with metastasis at the time of diagnosis, and the prognosis for these patients is poor. Therefore, novel potential prognostic biomarkers and therapeutic targets for ccRCC could be helpful. Emerging evidence indicates that lncRNAs play important roles in cancer tumorigenesis and could be used as potential biomarkers or therapeutic targets. PANDAR (promoter of CDKN1A antisense DNA damage activated RNA) is a relatively novel lncRNA that plays an important role in the development of multiple cancers. However, the clinical significance and molecular mechanism of PANDAR in ccRCC are still elusive. In the present study, we attempted to elucidate the role of PANDAR in ccRCC. METHODS: The relative expression level of lncRNA PANDAR was quantified by real-time qPCR in 62 paired ccRCC tissues and in renal cancer cell lines, and its association with overall survival was assessed by statistical analysis. The biological functions of lncRNA PANDAR on ccRCC cells were determined both in vitro and in vivo. RESULTS: PANDAR expression was significantly upregulated in tumor tissues and cell lines compared with normal counterparts. Moreover, PANDAR served as an independent predictor of overall survival, and increased PANDAR expression was positively correlated with an advanced TNM stage. Further experiments demonstrated that PANDAR silencing can significantly inhibit cell proliferation and invasion, induce cell cycle arrest in the G1 phase and significantly promote apoptosis in 7860 and Caki-1 cell lines. In addition, in vivo experiments confirmed that downregulation of PANDAR inhibited the tumorigenic ability of 7860 cells in nude mice. Silencing of PANDAR also inhibited the expression of Bcl-2 and Mcl-1 and upregulated the expression of Bax in vivo. CONCLUSIONS: Our results suggest that PANDAR is involved in ccRCC progression and may serve as a potential prognostic biomarker and therapeutic target.
Assuntos
Carcinoma de Células Renais/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias Renais/metabolismo , RNA Longo não Codificante/genética , Transdução de Sinais , Animais , Apoptose , Carcinoma de Células Renais/diagnóstico , Carcinoma de Células Renais/fisiopatologia , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Humanos , Neoplasias Renais/diagnóstico , Neoplasias Renais/fisiopatologia , Masculino , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Invasividade Neoplásica , Prognóstico , Proteínas Proto-Oncogênicas c-bcl-2 , RNA Longo não Codificante/metabolismoRESUMO
Paeonol (Pae) is the main active ingredient from the root bark of Paeonia moutan and the grass of Radix Cynanchi Paniculati. Numerous reports indicate that Pae effectively inhibits several types of cancer lines. In this study, we report that Pae hinders prostate cancer growth both in vivo and in vitro. Human prostate cancer lines DU145 and PC-3 were cultured in the presence of Pae. The xenograft tumor in mice was established by subcutaneous injection of DU145 cells. Cell growth was measured by MTT, and the apoptosis was detected by the flow cytometry. Expression of Bcl-2, Bax, Akt, and mTOR were tested by western blotting assay. DU145 and PC-3 showed remarkable sensitivity to Pae, and exposure to Pae induced dose-and time-dependent growth inhibitory responses. Moreover, treatment of Pae promoted apoptosis and enhanced activities of caspase-3, caspase-8, and caspase-9 in DU145. Further work demonstrated Pae reduced expression of Bcl-2 and increased expression of Bax in DU145. Interestingly, we observed that Pae significantly decreased phosphorylated status of Akt and mTOR, and inhibitory effects of Pae and PI3K/Akt inhibitor on DU145 proliferation were synergistic. Finally, we confirmed that oral administration of Pae to the DU145 tumor-bearing mice significantly lowered tumor cell proliferation and led to tumor regression. Pae possesses inhibitory effects on prostate cancer cell growth both in vitro and in vivo, and the anti-proliferative effect may be closely related to its activation of extrinsic and intrinsic apoptotic pathway and inhibition of the PI3K/Akt pathway.
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Acetofenonas/uso terapêutico , Antineoplásicos Fitogênicos/uso terapêutico , Suplementos Nutricionais , Neoplasias da Próstata/dietoterapia , Acanthaceae/química , Acetofenonas/administração & dosagem , Acetofenonas/sangue , Acetofenonas/metabolismo , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/sangue , Antineoplásicos Fitogênicos/metabolismo , Apoptose , Linhagem Celular Tumoral , Proliferação de Células , Etnofarmacologia , Humanos , Absorção Intestinal , Masculino , Medicina Tradicional Chinesa , Camundongos Nus , Paeonia/química , Casca de Planta/química , Componentes Aéreos da Planta/química , Raízes de Plantas/química , Poaceae/química , Neoplasias da Próstata/sangue , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Distribuição Aleatória , Carga Tumoral , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The design and optimization of a novel trans-1,4-dioxycyclohexane GPR119 agonist series is described. A lead compound 21 was found to be a potent and efficacious GPR119 agonist across species, and possessed overall favorable pharmaceutical properties. Compound 21 demonstrated robust acute and chronic regulatory effects on glycemic parameters in the diabetic or non-diabetic rodent models.
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Cicloexanos/química , Cicloexanos/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/química , Hipoglicemiantes/uso terapêutico , Receptores Acoplados a Proteínas G/agonistas , Administração Oral , Animais , Glicemia/análise , Cicloexanos/administração & dosagem , Cicloexanos/farmacocinética , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/farmacocinética , Masculino , Camundongos , Ratos Sprague-Dawley , Ratos Zucker , Receptores Acoplados a Proteínas G/metabolismo , Relação Estrutura-AtividadeRESUMO
Modulators of S1P1 have proven utility for the treatment of autoimmune disease and efforts to identify new agents with improved safety and pharmacokinetic parameters are ongoing. Several new S1P1 chemotypes were designed and optimized for potency and oral bioavailability. These new agents are characterized by a 'tricyclic fused indole array' and are highly potent agonists of the S1P1 receptor.
Assuntos
Desenho de Fármacos , Indóis/química , Receptores de Lisoesfingolipídeo/agonistas , Animais , Cães , Meia-Vida , Humanos , Indóis/síntese química , Indóis/farmacocinética , Camundongos , Ligação Proteica , Isoformas de Proteínas/agonistas , Isoformas de Proteínas/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de Lisoesfingolipídeo/metabolismo , Relação Estrutura-AtividadeRESUMO
OBJECTIVES: microRNAs (miRNAs) play essential roles in many tumors, including renal cell carcinoma (RCC). The aim of the present study was to investigate the expression and functional role of miR-29b in RCC and to identify its target genes. METHODS: We determined the expression of miR-29b in clear cell RCC (ccRCC) tissues and RCC cell lines (786-O, A498, and SN12-PM6) using quantitative real-time PCR (qRT-PCR). The associations between miR-29b expression and clinical pathological parameters and prognosis were explored. Besides, the role of miR-29b in the SN12-PM6 cells proliferation, apoptosis, cycle, and invasion were investigated after transduction with lentivirus vectors. The kines in family member 1B (KIF1B), possible miR-29b target genes, were predicted using bioinformatics approaches, as well as the role in the pathogenesis of RCC. RESULTS: Elevated expression of miR-29b was found in both tumor tissues and cell lines. High expression of miR-29b was significantly associated with tumor-node-metastasis (TNM) stage (P = 0.026) and the overall survival (P = 0.009) in the ccRCC. Inhibition of miR-29b expression could promote apoptosis, and inhibit proliferation and invasion ability in SN12-PM6 cells. Also, we confirmed that miR-29b could directly regulate the expression of KIF1B at the post transcriptional level. CONCLUSION: These data suggest that miR-29b acts as an oncomiR, promoting proliferation and invasion ability through KIF1B suppression, and it might be a potential marker for prognosis of RCC.
Assuntos
Carcinoma de Células Renais/metabolismo , Neoplasias Renais/metabolismo , MicroRNAs/metabolismo , Idoso , Apoptose , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/mortalidade , Carcinoma de Células Renais/patologia , Ciclo Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Biologia Computacional , Bases de Dados Genéticas , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Neoplasias Renais/genética , Neoplasias Renais/mortalidade , Neoplasias Renais/patologia , Cinesinas/genética , Cinesinas/metabolismo , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , Invasividade Neoplásica , Estadiamento de Neoplasias , TransfecçãoRESUMO
The design and synthesis of novel 1a,2,5,5a-tetrahydro-1H-2,3-diaza-cyclopropa[a]pentalen-4-carboxamide CB2 selective ligands for the potential treatment of pain is described. Compound (R,R)-25 has good balance between CB2 agonist potency and selectivity over CB1, and possesses overall favorable pharmaceutical properties. It also demonstrated robust in vivo efficacy mediated via CB2 activation in the rodent models of inflammatory and osteoarthritis pain after oral administration.
Assuntos
Analgésicos não Narcóticos/farmacologia , Compostos Heterocíclicos com 3 Anéis/farmacologia , Inflamação/tratamento farmacológico , Microssomos Hepáticos/efeitos dos fármacos , Osteoartrite/tratamento farmacológico , Dor/tratamento farmacológico , Pirazóis/farmacologia , Receptor CB2 de Canabinoide/agonistas , Administração Oral , Analgésicos não Narcóticos/administração & dosagem , Analgésicos não Narcóticos/química , Animais , Artrite Experimental/tratamento farmacológico , Artrite Experimental/metabolismo , Compostos Heterocíclicos com 3 Anéis/administração & dosagem , Compostos Heterocíclicos com 3 Anéis/química , Humanos , Inflamação/metabolismo , Masculino , Microssomos Hepáticos/metabolismo , Modelos Moleculares , Estrutura Molecular , Osteoartrite/metabolismo , Dor/metabolismo , Pirazóis/administração & dosagem , Pirazóis/química , Ensaio Radioligante , Ratos , Ratos Sprague-Dawley , Receptor CB1 de Canabinoide/agonistas , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
APD334 was discovered as part of our internal effort to identify potent, centrally available, functional antagonists of the S1P1 receptor for use as next generation therapeutics for treating multiple sclerosis (MS) and other autoimmune diseases. APD334 is a potent functional antagonist of S1P1 and has a favorable PK/PD profile, producing robust lymphocyte lowering at relatively low plasma concentrations in several preclinical species. This new agent was efficacious in a mouse experimental autoimmune encephalomyelitis (EAE) model of MS and a rat collagen induced arthritis (CIA) model and was found to have appreciable central exposure.
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S1P1 is a validated target for treatment of autoimmune disease, and functional antagonists with superior safety and pharmacokinetic properties are being sought as second generation therapeutics. We describe the discovery and optimization of (7-benzyloxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetic acids as potent, centrally available, direct acting S1P1 functional antagonists, with favorable pharmacokinetic and safety properties.
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Two series of fused tricyclic indoles were identified as potent and selective S1P(1) agonists. In vivo these agonists produced a significant reduction in circulating lymphocytes which translated into robust efficacy in several rodent models of autoimmune disease. Importantly, these agonists were devoid of any activity at the S1P(3) receptor in vitro, and correspondingly did not produce S1P(3) mediated bradycardia in telemeterized rat.
Assuntos
Fatores Imunológicos/química , Indóis/química , Receptores de Lisoesfingolipídeo/agonistas , Animais , Doenças Autoimunes/tratamento farmacológico , Modelos Animais de Doenças , Feminino , Humanos , Fatores Imunológicos/farmacocinética , Fatores Imunológicos/uso terapêutico , Indóis/farmacocinética , Indóis/uso terapêutico , Linfócitos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microssomos/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de Lisoesfingolipídeo/metabolismo , Relação Estrutura-AtividadeRESUMO
OBJECTIVE: To investigate the effectiveness of reverse island flaps of digital artery parallel for repairing degloved injuries of the fingertip. METHODS: Between June 2008 and January 2010, 13 cases of degloved injuries of the fingertip were treated. There were 8 males and 5 females with an average age of 34 years (range, 19-62 years). The causes of injuries were as follow: impact and press injury in 5 cases, wringer injury in 7 cases, and crush injury in 1 case. The injured fingers were comprised of index finger in 6 cases, middle finger in 4 cases, ring finger in 2 cases, and little finger in 1 case. The size of skin and soft tissue defect ranged from 2.0 cm x 1.8 cm to 3.0 cm x 2.5 cm. Three cases complicated by fracture of the distal phalanx, 1 case by rupture of the insertion of extensor tendon, and 1 case by rupture of the insertion of flexor tendon. The average time from injure to surgery was 4 hours (range, 1 hour and 30 minutes-12 hours). Two neighboring skin flaps located in the same course of digital artery were adopted to repair defect of the fingertip. The size of proximal skin flap ranged from 1.2 cm x 1.0 cm to 2.0 cm x 1.5 cm and the size of distal skin flap ranged from 1.1 cm x 1.0 cm to 1.5 cm x 1.3 cm. The free skin grafts were used to repair the donor sites. RESULTS: Circulation crisis occurred in 1 case at 2 hours after operation and was eliminated by interval disconnecting. The other flaps and skin grafts survived and the wounds healed by first intention. The patients were followed up 6-18 months (mean, 10 months). All flaps presented the satisfactory appearance and texture, and the flexion and extension function of wounded fingers recovered to normal. Two-point discrimination ranged from 7 to 11 mm at last follow-up. According to the functional assessment criteria of upper limb formulated by the Hand Surgery Branch of Chinese Medical Association, the results were excellent in 9 cases, good in 3 cases, and fair in 1 case with an excellent and good rate of 92.3%. CONCLUSION: Based on the anatomical features of communicating branches of distal interphalangeal joint, two neighboring flaps located in the same course of digital artery are adopted to repair soft tissue defect of the fingertip. This surgical method is a simple and effective method.
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Traumatismos dos Dedos/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Retalhos Cirúrgicos , Adulto , Artérias/transplante , Feminino , Dedos/irrigação sanguínea , Humanos , Masculino , Pessoa de Meia-Idade , Transplante de Pele , Retalhos Cirúrgicos/irrigação sanguínea , Adulto JovemRESUMO
Using a high-throughput chemical screen, we identified two small molecules that enhance the survival of human embryonic stem cells (hESCs). By characterizing their mechanisms of action, we discovered an essential role of E-cadherin signaling for ESC survival. Specifically, we showed that the primary cause of hESC death following enzymatic dissociation comes from an irreparable disruption of E-cadherin signaling, which then leads to a fatal perturbation of integrin signaling. Furthermore, we found that stability of E-cadherin and the resulting survival of ESCs were controlled by specific growth factor signaling. Finally, we generated mESC-like hESCs by culturing them in mESC conditions. And these converted hESCs rely more on E-cadherin signaling and significantly less on integrin signaling. Our data suggest that differential usage of cell adhesion systems by ESCs to maintain self-renewal may explain their profound differences in terms of morphology, growth factor requirement, and sensitivity to enzymatic cell dissociation.
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Células-Tronco Embrionárias/metabolismo , Células-Tronco Pluripotentes/metabolismo , Transdução de Sinais , Animais , Caderinas/metabolismo , Adesão Celular , Comunicação Celular , Forma Celular , Sobrevivência Celular , Células Cultivadas , Células-Tronco Embrionárias/citologia , Matriz Extracelular/metabolismo , Humanos , Integrinas/metabolismo , Camundongos , Células-Tronco Pluripotentes/citologia , Proteínas rho de Ligação ao GTP/metabolismo , Quinases Associadas a rho/metabolismoRESUMO
Bcl-2 can be converted into a proapoptotic molecule by nuclear receptor Nur77. However, the development of Bcl-2 converters as anticancer therapeutics has not been explored. Here we report the identification of a Nur77-derived Bcl-2-converting peptide with 9 amino acids (NuBCP-9) and its enantiomer, which induce apoptosis of cancer cells in vitro and in animals. The apoptotic effect of NuBCPs and their activation of Bax are not inhibited but rather potentiated by Bcl-2. NuBCP-9 and its enantiomer bind to the Bcl-2 loop, which shares the characteristics of structurally adaptable regions with many cancer-associated and signaling proteins. NuBCP-9s act as molecular switches to dislodge the Bcl-2 BH4 domain, exposing its BH3 domain, which in turn blocks the activity of antiapoptotic Bcl-X(L).
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Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Proteínas de Ligação a DNA/metabolismo , Neoplasias Experimentais/tratamento farmacológico , Oligopeptídeos/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Receptores de Esteroides/metabolismo , Animais , Antineoplásicos/química , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/metabolismo , Sítios de Ligação , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Proteínas de Ligação a DNA/genética , Relação Dose-Resposta a Droga , Feminino , Células HeLa , Humanos , Células Jurkat , Camundongos , Camundongos Knockout , Camundongos SCID , Neoplasias Experimentais/genética , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares , Oligopeptídeos/química , Fragmentos de Peptídeos/farmacologia , Ligação Proteica , Conformação Proteica , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/química , Proteínas Proto-Oncogênicas c-bcl-2/genética , Receptores de Esteroides/genética , Estereoisomerismo , Fatores de Tempo , Transfecção , Ensaios Antitumorais Modelo de Xenoenxerto , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo , Proteína bcl-X/metabolismoRESUMO
Epstein-Barr virus is a human herpesvirus that causes infectious mononucleosis and lymphoproliferative malignancies. LMP1 (latent membrane protein-1), which is encoded by this virus and which is essential for transformation of B lymphocytes, acts as a constitutively active mimic of the tumor necrosis factor receptor (TNFR) CD40. LMP1 is an integral membrane protein containing six transmembrane segments and a cytoplasmic domain at the C terminus that binds to intracellular TNFR-associated factors (TRAFs). TRAFs are intracellular co-inducers of downstream signaling from CD40 and other TNFRs, and TRAF3 is required for activation of B lymphocytes by LMP1. Cytoplasmic C-terminal activation region 1 of LMP1 bears a motif (PQQAT) that conforms to the TRAF recognition motif PVQET in CD40. In this study, we report the crystal structure of this portion of LMP1 C-terminal activation region-1 (204PQQATDD210) bound in complex with TRAF3. The PQQAT motif is bound in the same binding crevice on TRAF3 where CD40 is bound, providing a molecular mechanism for LMP1 to act as a CD40 decoy for TRAF3. The LMP1 motif is presented in the TRAF3 crevice as a close structural mimic of the PVQET motif in CD40, and the intermolecular contacts are similar. However, the viral protein makes a unique contact: a hydrogen bond network formed between Asp210 in LMP1 and Tyr395 and Arg393 in TRAF3. This intermolecular contact is not made in the CD40-TRAF3 complex. The additional hydrogen bonds may stabilize the complex and strengthen the binding to permit LMP1 to compete with CD40 for binding to the TRAF3 crevice, influencing downstream signaling to B lymphocytes and contributing to dysregulated signaling by LMP1.
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Linfócitos B/metabolismo , Antígenos CD40/química , Herpesvirus Humano 4/química , Fator 3 Associado a Receptor de TNF/metabolismo , Proteínas da Matriz Viral/química , Proteínas da Matriz Viral/metabolismo , Alanina/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Linfócitos B/virologia , Sítios de Ligação , Western Blotting , Antígenos CD40/metabolismo , Transformação Celular Viral , Cristalografia por Raios X , Humanos , Ativação Linfocitária , Camundongos , Microscopia de Fluorescência , Modelos Moleculares , Testes de Precipitina , Transfecção , Proteínas da Matriz Viral/genéticaRESUMO
Humanin (HN) is a recently identified endogenous peptide that protects cells against cytotoxicity induced by various stimuli. Recently, we showed that HN binds to and inhibits Bax, a proapoptotic Bcl-2 family protein, suggesting a mechanism for HN action. In this study, we identified Bim, a Bcl-2 homology 3-only member of the Bcl-2/Bax family, as an additional HN target protein. Using in vitro protein binding, immunoprecipitation, and coimmunolocalization assays, we demonstrated that HN binds directly to the extra long isoform of Bim (BimEL) but not the long (BimL) or short (BimS) isoforms. HN also protects cells against apoptosis induced by BimEL but not BimL and BimS in gene transfection studies. In contrast, mutants of HN which failed to bind BimEL failed to protect from BimEL-induced cell death. Moreover, HN inhibited BimEL-induced release of SMAC and cytochrome c from mitochondria isolated from bax-/-cells, indicating that HN can suppress BimEL independently of its effect on Bax. Finally, we demonstrate that HN prevents BimEL-induced oligomerization of Bak using isolated mitochondria. Taken together, our results indicate that the inhibition of BimEL may contribute to the antiapoptotic properties of the HN peptide.