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1.
Nat Prod Res ; : 1-9, 2023 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-37859413

RESUMO

This research aims to explore the saponins composition of H. nepalensis in four northwest mountainous areas of Vietnam including Ha Giang, Lai Chau, Lao Cai, and Lang Son with the aid of high-resolution mass spectrometry. As a result, 42 saponins are successfully identified in H. nepalensis leaves by UHPLC-Q-TOF-MS/MS analyses, in which two 30-noroleanane and four oleanane triterpene saponins structures have been reported for the first time. Two structures of compound 20 were discovered in four samples. Two structures of compound 8 were found in H. nepalensis from Ha Giang and Lao Cai, while two structures of compound 28 were not observed in Lang Son. Different environmental and climatic circumstances in various places may have an impact on chemical constituents of H. nepalensis. By providing the phytochemicals profile of H. nepalensis leaves, our study supports the orientation for future research on this medicinal plant as well as other Hedera species.

2.
Chem Biodivers ; 20(8): e202300649, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37471031

RESUMO

This study was aimed to investigate the chemical composition and biological activities of leaf and stem essential oils of Zanthoxylum acanthopodium DC. from Vietnam. Their chemical composition was analyzed by GC/MS. Antimicrobial activities were evaluated by microdilution broth assay. Anti-inflammatory activity was evaluated by the ability to inhibit nitric oxide production in macrophage cells. Cytotoxic activity was evaluated using the sulforhodamine B assay on three human cancer cell lines. Forty-four compounds were identified in the leaf oil, among which dehydroaromadendrane (23.4 %), (E)-carpacin (17.6 %), 2-tridecanone (12.2 %), and 9-methyl-2-decanone (11.8 %) were the most abundant. The stem oil contained fifty-five identified constituents, mainly γ-gurjunene (51.1 %) and butyl acetate (11.8 %). Both oils exhibited inhibitory effects on three bacterial strains, namely S. aureus, E. coli, P. aeruginosa and a fungal strain C. albican, while showed insignificant effects on B. subtilis, L. fermentum, and S. enterica. Both oils showed weak NO production inhibition in LPS-induced RAW264.7 cells, but exhibited potent cytotoxic activity against all three tested cell lines SK-LU-1, MCF-7, and HepG2 with the IC50 values ranging from 16.03±0.77 to 35.60±1.62 µg/mL. This is the first report on the antimicrobial, anti-inflammatory and cytotoxic activities of essential oils from the leaves and stems of Z. acanthopodium.


Assuntos
Anti-Infecciosos , Antineoplásicos , Óleos Voláteis , Zanthoxylum , Humanos , Óleos Voláteis/química , Zanthoxylum/química , Óxido Nítrico , Vietnã , Escherichia coli , Staphylococcus aureus , Anti-Infecciosos/química , Antineoplásicos/farmacologia , Folhas de Planta/química , Anti-Inflamatórios/análise , Testes de Sensibilidade Microbiana
3.
Nat Prod Res ; : 1-10, 2023 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-37337451

RESUMO

New essential oils (EOs) extracted from different parts of two Luvunga species (L. scandens and L. hongiaoensis) from Vietnam were investigated for their chemical composition, anti-inflammatory and cytotoxic activity. Sixty-nine total compounds were identified in the EOs by GC/MS. The major constituent of the leaf, fruit, and root EOs from L. scandens was ß-caryophyllene (71.5%, 63.0%, and 31.5% respectively). The main compounds in L. hongiaoensis EOs were ß-elemene (34.3% in leaf oil) and caryophyllene oxide (21.2% in root oil, 19.4% in stem oil). The EO from L. scandens fruits significantly inhibited nitric oxide production on LPS-induced RAW264.7 cells (IC50 = 37.95 ± 2.76 µg/mL). The EOs from L. hongiaoensis roots and L. scandens leaves and fruits exhibited cytotoxic activity against MCF-7, SK-LU-1, and HepG2 (IC50 from 49.74 ± 3.36 to 97.82 ± 8.61 µg/mL). This is the first report on L. hongiaoensis EOs and significantly complements the composition and bioactivity of L. scandens EOs.

4.
Cancer Nurs ; 46(3): 233-247, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35349543

RESUMO

BACKGROUND: Stomas in colorectal cancer (CRC) survivors lead to body image problems. Advances in treatment help reduce the rate of stoma formation, but body image distress is still frequently experienced in CRC survivors. OBJECTIVES: This review is aimed toward mapping and describing the state of knowledge regarding body image in patients with CRC. METHODS: A systematic literature search complying with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines was conducted. Screening and data extraction were performed by 2 reviewers independently for all potentially eligible studies. RESULTS: A total of 56 eligible articles were selected. The majority of these studies were quantitative studies (85%). The eligible studies were classified into 4 broad categories: instruments used to assess body image, prevalence of body image distress, factors related to body image, and impact of body image distress. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-CR38) colorectal questionnaire was the most common measurement tool found among the reviewed studies (70%), and body image distress was reported by 25.5% to 86% of participants. Excluding gender, age, type of surgery, adjuvant therapy, time from diagnosis, social support, and stoma status, changes in bowel habits was identified as affecting the body image of patients with CRC. CONCLUSION: Changing bowel habits emerged as a significant factor causing body image distress for CRC survivors. IMPLICATIONS FOR PRACTICE: Clinicians should raise awareness about body image distress in patients with CRC, focus on finding effective measures and interventions intended to help alleviate symptoms of bowel dysfunction, and prepare patients to adapt to altered bowel functions.


Assuntos
Sobreviventes de Câncer , Neoplasias Colorretais , Humanos , Imagem Corporal , Neoplasias Colorretais/terapia , Neoplasias Colorretais/cirurgia , Qualidade de Vida , Inquéritos e Questionários , Sobreviventes
5.
J Anal Methods Chem ; 2022: 1167265, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35979140

RESUMO

Hedera helix has been reported to contain a wide range of metabolites and produce many pharmacological effects. This research demonstrates the determination and evaluation of the phytochemical profiling of H. helix grown in central Vietnam. Methanolic extract of ivy had been analyzed by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). MS, and MS/MS experiments were manipulated using both negative and positive ionization modes to provide molecular mass information and production spectra for the structural elucidation of compounds. A total of 46 compounds including 24 triterpene saponins and other compounds were successfully identified of which four established saponin structures have been reported for the first time. This study has provided a base for building a quality control of the raw materials according to the profile of triterpene saponins and assessment of pharmaceutical ingredients of H. helix planted in Vietnam.

6.
Cancers (Basel) ; 14(4)2022 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-35205610

RESUMO

Circular RNAs (circRNAs) are noncoding products of backsplicing of pre-mRNAs which have been established to possess potent biological functions. Dysregulated circRNA expression has been linked to diseases including different types of cancer. Cancer progression is known to result from the dysregulation of several molecular mechanisms responsible for the maintenance of cellular and tissue homeostasis. The dysregulation of these processes is defined as cancer hallmarks, and the molecular pathways implicated in them are regarded as the targets of therapeutic interference. In this review, we summarize the literature on the investigation of circRNAs implicated in cancer hallmark molecular signaling. First, we present general information on the properties of circRNAs, such as their biogenesis and degradation mechanisms, as well as their basic molecular functions. Subsequently, we summarize the roles of circRNAs in the framework of each cancer hallmark and finally discuss the potential as therapeutic targets.

7.
Nat Med ; 26(8): 1264-1270, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32661391

RESUMO

Cancer cachexia is a highly prevalent condition associated with poor quality of life and reduced survival1. Tumor-induced perturbations in the endocrine, immune and nervous systems drive anorexia and catabolic changes in adipose tissue and skeletal muscle, hallmarks of cancer cachexia2-4. However, the molecular mechanisms driving cachexia remain poorly defined, and there are currently no approved drugs for the condition. Elevation in circulating growth differentiation factor 15 (GDF15) correlates with cachexia and reduced survival in patients with cancer5-8, and a GDNF family receptor alpha like (GFRAL)-Ret proto-oncogene (RET) signaling complex in brainstem neurons that mediates GDF15-induced weight loss in mice has recently been described9-12. Here we report a therapeutic antagonistic monoclonal antibody, 3P10, that targets GFRAL and inhibits RET signaling by preventing the GDF15-driven interaction of RET with GFRAL on the cell surface. Treatment with 3P10 reverses excessive lipid oxidation in tumor-bearing mice and prevents cancer cachexia, even under calorie-restricted conditions. Mechanistically, activation of the GFRAL-RET pathway induces expression of genes involved in lipid metabolism in adipose tissues, and both peripheral chemical sympathectomy and loss of adipose triglyceride lipase protect mice from GDF15-induced weight loss. These data uncover a peripheral sympathetic axis by which GDF15 elicits a lipolytic response in adipose tissue independently of anorexia, leading to reduced adipose and muscle mass and function in tumor-bearing mice.


Assuntos
Caquexia/tratamento farmacológico , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/genética , Fator 15 de Diferenciação de Crescimento/genética , Complexos Multiproteicos/ultraestrutura , Neoplasias/tratamento farmacológico , Proteínas Proto-Oncogênicas c-ret/genética , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Animais , Anticorpos Monoclonais , Caquexia/complicações , Caquexia/genética , Caquexia/imunologia , Linhagem Celular Tumoral , Cristalografia por Raios X , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/ultraestrutura , Fator 15 de Diferenciação de Crescimento/ultraestrutura , Xenoenxertos , Humanos , Peroxidação de Lipídeos , Camundongos , Complexos Multiproteicos/genética , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/patologia , Neoplasias/complicações , Neoplasias/genética , Neoplasias/imunologia , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-ret/ultraestrutura , Transdução de Sinais , Redução de Peso
8.
Molecules ; 25(12)2020 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-32599892

RESUMO

Cancer is the second leading cause of death globally, and despite the advances in drug development, it is still necessary to develop new plant-derived medicines. Compared with using conventional chemical drugs to decrease the side effects induced by chemotherapy, natural herbal medicines have many advantages. The present study aimed to discover the potential cytotoxicity of ethanol extract and its derived fractions (chloroform, ethyl acetate, butanol, and aqueous) of Adenosma bracteosum Bonati. (A. bracteosum) on human large cell lung carcinoma (NCI-H460) and hepatocellular carcinoma (HepG2). Among these fractions, the chloroform showed significant activity in the inhibition of proliferation of both cancerous cells because of the presence of bioactive compounds including xanthomicrol, 5,4'-dihydroxy-6,7,8,3'-tetramethoxyflavone, and ursolic acid which were clearly revealed by nuclear magnetic resonance spectroscopy (1H-NMR, 13C-NMR, Heteronuclear Multiple Bond Coherence, and Heteronuclear Single Quantum Coherence Spectroscopy) analyses. According to the radical scavenging capacity, the 5,4'-dihydroxy-6,7,8,3'-tetramethoxyflavone compound (AB2) exhibited the highest anticancer activity on both NCI-H460 and HepG2 with IC50 values of 4.57 ± 0.32 and 5.67 ± 0.09 µg/mL respectively, followed by the ursolic acid with the lower percent inhibition at 13.05 ± 0.55 and 10.00 ± 0.16 µg/mL, respectively (p < 0.05). Remarkably, the AB2 compound induced to significant increase in the production of reactive oxygen species accompanied by attenuation of mitochondrial membrane potential, thus inducing the activation of caspase-3 activity in both human lung and liver cancer cells. These results suggest that A. bracteosum is a promising source of useful natural products and AB2 offers opportunities to develop the novel anticancer drugs.


Assuntos
Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Extratos Vegetais/farmacologia , Plantaginaceae/química , Animais , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Artemia/efeitos dos fármacos , Caspase 3/metabolismo , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Flavonas/química , Flavonas/farmacologia , Flavonoides/química , Flavonoides/farmacologia , Células Hep G2 , Humanos , Neoplasias Pulmonares/patologia , Espectroscopia de Ressonância Magnética , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Estrutura Molecular , Extratos Vegetais/química , Espécies Reativas de Oxigênio/metabolismo
9.
Materials (Basel) ; 12(8)2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30999642

RESUMO

This paper presents a finite element formulation to study the mechanical buckling of stiffened functionally graded material (FGM) plates. The approach is based on a third-order shear deformation theory (TSDT) introduced by Guangyu Shi. The material properties of the plate were assumed to be varied in the thickness direction by a power law distribution, but the material of the stiffener was the same as that of the one of the bottom surface where the stiffener was placed. A parametric study was carried out to highlight the effect of material distribution, the thickness-to-width ratio, and stiffener parameters on the buckling characteristics of the stiffened FGM plates. Numerical results showed that the addition of stiffener to the FGM plate could significantly reduce the weight of the FGM plate but that both the FGM plates with and without stiffener had equally high strength in the same boundary condition and compression loading.

10.
Braz. J. Pharm. Sci. (Online) ; 54(1): e17178, 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-951912

RESUMO

ABSTRACT Antioxidants from natural sources hold high values regarding their indispensible roles in the development of nutraceuticals, pharmaceuticals and cosmetic products. Oroxylum indicum L. is a common medicinal plant with a wide range of therapeutic properties, including a notable antioxidant potency that was reported, yet has not been subjected to more detailed studies. The present study evaluated the potency of Oroxylum indicum methanol stem bark extract, along with its hexane, ethyl acetate, methanol fractions, three flavones including baicalein, oroxylin A and chrysin using DPPH assay. In terms of IC50 values, the crude extract (65,48 µg/mL) exhibited moderate inhibitory activity which was as half potent as that of its ethyl acetate fraction (32,94 µg/mL). This fraction was also superior to the methanol and hexane fractions, as their IC50 were 57,19 and 137,95 µg/mL respectively. Remarkably, a yellow powdery sub-fraction consisted of isolated compounds showed powerful activity (32,89 µg/mL) compared to those of its components, revealing the intriguing effect of synergism while giving evidence for the theory of structure-activity relationship between some flavones and their antioxidant capability. Perpetual search for new radical scavenging agents in Oroxylum indicum is emboldened considering its partially exploited potential in this study


Assuntos
Extratos Vegetais/análise , Bignoniaceae/classificação , Metanol/análise , Antioxidantes/efeitos adversos , Técnicas In Vitro , Caules de Planta/efeitos adversos , Concentração Inibidora 50 , Casca de Planta/efeitos adversos , Flavonas
11.
Dokl Biochem Biophys ; 476(1): 316-319, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29101740

RESUMO

Low-molecular-weight compounds with anticoagulant activity were isolated from the scorpion Heterometrus laoticus venom. The determination of the structure of the isolated compounds by nuclear magnetic resonance and mass spectrometry showed that one of the isolated compounds is adenosine, and the other two are dipeptides leucyl-tryptophan and isoleucyl-tryptophan. The anticoagulant properties of adenosine, which is an inhibitor of platelet aggregation, is well known, but its presence in scorpion venom is shown for the first time. The ability of leucyl-tryptophan and isoleucyl-tryptophan to slow down blood clotting and their presence in scorpion venom are also established for the first time.


Assuntos
Anticoagulantes/química , Anticoagulantes/farmacologia , Venenos de Escorpião/química , Escorpiões , Animais , Camundongos , Peso Molecular
12.
Public Health Rep ; 131(3): 396-403, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27252559

RESUMO

Although improving health systems promises important benefits, most developing nations lack the resources to support nationally driven clinical research. Strengthened clinical research capacity can advance national health goals by supporting greater autonomy in aligning research with national priorities. From March through June 2010, we assessed six elements of clinical research capacity in Vietnam: research agenda; clinical investigators and biostatisticians; donors and sponsors; community involvement; scientific, ethical, safety, and quality oversight; and clinical research institutions. Assessments were drawn from interviews with investigators, Ministry of Health staff members, nongovernment organizations, and U.S. Mission staff members, and document review. Observations and recommendations were shared with collaborators. Reassessment in 2015 found growth in the number of clinical trials, improved regulation in human subjects protection and community engagement, and modest advances in research agenda setting. Training and investment in institutions remain challenging. A framework for assessing clinical research capacity can affirm strengths and weaknesses and guide the coordination of capacity-building efforts.


Assuntos
Pesquisa Biomédica , Fortalecimento Institucional , Ensaios Clínicos como Assunto , Países em Desenvolvimento , Pesquisa Biomédica/economia , Fortalecimento Institucional/economia , Ensaios Clínicos como Assunto/economia , Humanos , Estados Unidos , Vietnã
13.
ACS Med Chem Lett ; 6(5): 562-7, 2015 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-26005534

RESUMO

Deregulated kinase activities of tropomyosin receptor kinase (TRK) family members have been shown to be associated with tumorigenesis and poor prognosis in a variety of cancer types. In particular, several chromosomal rearrangements involving TRKA have been reported in colorectal, papillary thyroid, glioblastoma, melanoma, and lung tissue that are believed to be the key oncogenic driver in these tumors. By screening the Novartis compound collection, a novel imidazopyridazine TRK inhibitor was identified that served as a launching point for drug optimization. Structure guided drug design led to the identification of (R)-2-phenylpyrrolidine substituted imidazopyridazines as a series of potent, selective, orally bioavailable pan-TRK inhibitors achieving tumor regression in rats bearing KM12 xenografts. From this work the (R)-2-phenylpyrrolidine has emerged as an ideal moiety to incorporate in bicyclic TRK inhibitors by virtue of its shape complementarity to the hydrophobic pocket of TRKs.

14.
Sci Transl Med ; 6(247): 247ra100, 2014 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-25080475

RESUMO

Hepatic accumulation of bile acids is central to the pathogenesis of cholestatic liver diseases. Endocrine hormone fibroblast growth factor 19 (FGF19) may reduce hepatic bile acid levels through modulation of bile acid synthesis and prevent subsequent liver damage. However, FGF19 has also been implicated in hepatocellular carcinogenesis, and consequently, the potential risk from prolonged exposure to supraphysiological levels of the hormone represents a major hurdle for developing an FGF19-based therapy. We describe a nontumorigenic FGF19 variant, M70, which regulates bile acid metabolism and, through inhibition of bile acid synthesis and reduction of excess hepatic bile acid accumulation, protects mice from liver injury induced by either extrahepatic or intrahepatic cholestasis. Administration of M70 in healthy human volunteers potently reduces serum levels of 7α-hydroxy-4-cholesten-3-one, a surrogate marker for the hepatic activity of cholesterol 7α-hydroxylase (CYP7A1), the enzyme responsible for catalyzing the first and rate-limiting step in the classical bile acid synthetic pathway. This study provides direct evidence for the regulation of bile acid metabolism by FGF19 pathway in humans. On the basis of these results, the development of nontumorigenic FGF19 variants capable of modulating CYP7A1 expression represents an effective approach for the prevention and treatment of cholestatic liver diseases as well as potentially for other disorders associated with bile acid dysregulation.


Assuntos
Ácidos e Sais Biliares/metabolismo , Colagogos e Coleréticos/uso terapêutico , Colestase Extra-Hepática/tratamento farmacológico , Colestase Intra-Hepática/tratamento farmacológico , Fatores de Crescimento de Fibroblastos/uso terapêutico , Fígado/efeitos dos fármacos , Adulto , Animais , Austrália , Biomarcadores/sangue , Colagogos e Coleréticos/efeitos adversos , Colagogos e Coleréticos/farmacocinética , Colestase Extra-Hepática/genética , Colestase Extra-Hepática/metabolismo , Colestase Extra-Hepática/patologia , Colestase Intra-Hepática/genética , Colestase Intra-Hepática/metabolismo , Colestase Intra-Hepática/patologia , Colestenonas/sangue , Colesterol 7-alfa-Hidroxilase/genética , Colesterol 7-alfa-Hidroxilase/metabolismo , Modelos Animais de Doenças , Método Duplo-Cego , Regulação para Baixo , Fatores de Crescimento de Fibroblastos/efeitos adversos , Fatores de Crescimento de Fibroblastos/biossíntese , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/farmacocinética , Regulação Enzimológica da Expressão Gênica , Técnicas de Transferência de Genes , Variação Genética , Voluntários Saudáveis , Humanos , Fígado/metabolismo , Fígado/patologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Pessoa de Meia-Idade , RNA Mensageiro/metabolismo , Proteínas Recombinantes/uso terapêutico , Medição de Risco , Adulto Jovem
15.
Cancer Res ; 74(12): 3306-16, 2014 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-24728076

RESUMO

Hepatocellular carcinoma (HCC), one of the leading causes of cancer-related death, develops from premalignant lesions in chronically damaged livers. Although it is well established that FGF19 acts through the receptor complex FGFR4-ß-Klotho (KLB) to regulate bile acid metabolism, FGF19 is also implicated in the development of HCC. In humans, FGF19 is amplified in HCC and its expression is induced in the liver under cholestatic and cirrhotic conditions. In mice, ectopic overexpression of FGF19 drives HCC development in a process that requires FGFR4. In this study, we describe an engineered FGF19 (M70) that fully retains bile acid regulatory activity but does not promote HCC formation, demonstrating that regulating bile acid metabolism is distinct and separable from tumor-promoting activity. Mechanistically, we show that FGF19 stimulates tumor progression by activating the STAT3 pathway, an activity eliminated by M70. Furthermore, M70 inhibits FGF19-dependent tumor growth in a rodent model. Our results suggest that selectively targeting the FGF19-FGFR4 pathway may offer a tractable approach to improve the treatment of chronic liver disease and cancer.


Assuntos
Ácidos e Sais Biliares/metabolismo , Carcinogênese/metabolismo , Carcinoma Hepatocelular/metabolismo , Fatores de Crescimento de Fibroblastos/genética , Neoplasias Hepáticas Experimentais/metabolismo , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Linhagem Celular Tumoral , Colesterol 7-alfa-Hidroxilase/metabolismo , Dependovirus/genética , Fatores de Crescimento de Fibroblastos/biossíntese , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Dados de Sequência Molecular , Ligação Proteica , Ratos , Receptor Tipo 4 de Fator de Crescimento de Fibroblastos/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Deleção de Sequência , Transdução de Sinais
16.
Proc Natl Acad Sci U S A ; 110(50): 20224-9, 2013 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-24277854

RESUMO

Wnt signaling is one of the key oncogenic pathways in multiple cancers, and targeting this pathway is an attractive therapeutic approach. However, therapeutic success has been limited because of the lack of therapeutic agents for targets in the Wnt pathway and the lack of a defined patient population that would be sensitive to a Wnt inhibitor. We developed a screen for small molecules that block Wnt secretion. This effort led to the discovery of LGK974, a potent and specific small-molecule Porcupine (PORCN) inhibitor. PORCN is a membrane-bound O-acyltransferase that is required for and dedicated to palmitoylation of Wnt ligands, a necessary step in the processing of Wnt ligand secretion. We show that LGK974 potently inhibits Wnt signaling in vitro and in vivo, including reduction of the Wnt-dependent LRP6 phosphorylation and the expression of Wnt target genes, such as AXIN2. LGK974 is potent and efficacious in multiple tumor models at well-tolerated doses in vivo, including murine and rat mechanistic breast cancer models driven by MMTV-Wnt1 and a human head and neck squamous cell carcinoma model (HN30). We also show that head and neck cancer cell lines with loss-of-function mutations in the Notch signaling pathway have a high response rate to LGK974. Together, these findings provide both a strategy and tools for targeting Wnt-driven cancers through the inhibition of PORCN.


Assuntos
Proteínas de Membrana/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Pirazinas/farmacologia , Piridinas/farmacologia , Via de Sinalização Wnt/efeitos dos fármacos , Aciltransferases , Animais , Proteína Axina/antagonistas & inibidores , Western Blotting , Linhagem Celular Tumoral , Clonagem Molecular , Ensaios de Triagem em Larga Escala , Humanos , Camundongos , Mutagênese , Fosforilação/efeitos dos fármacos , Pirazinas/uso terapêutico , Piridinas/uso terapêutico , Ensaio Radioligante , Ratos , Receptores Notch/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
17.
PLoS One ; 5(11): e14020, 2010 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-21103359

RESUMO

Dementia with Lewy bodies (DLB) and Parkinson's Disease (PD) are neurodegenerative disorders of the aging population characterized by the abnormal accumulation of alpha-synuclein (alpha-syn). Previous studies have suggested that excitotoxicity may contribute to neurodegeneration in these disorders, however the underlying mechanisms and their relationship to alpha-syn remain unclear. For this study we proposed that accumulation of alpha-syn might result in alterations in metabotropic glutamate receptors (mGluR), particularly mGluR5 which has been linked to deficits in murine models of PD. In this context, levels of mGluR5 were analyzed in the brains of PD and DLB human cases and alpha-syn transgenic (tg) mice and compared to age-matched, unimpaired controls, we report a 40% increase in the levels of mGluR5 and beta-arrestin immunoreactivity in the frontal cortex, hippocampus and putamen in DLB cases and in the putamen in PD cases. In the hippocampus, mGluR5 was more abundant in the CA3 region and co-localized with alpha-syn aggregates. Similarly, in the hippocampus and basal ganglia of alpha-syn tg mice, levels of mGluR5 were increased and mGluR5 and alpha-syn were co-localized and co-immunoprecipitated, suggesting that alpha-syn interferes with mGluR5 trafficking. The increased levels of mGluR5 were accompanied by a concomitant increase in the activation of downstream signaling components including ERK, Elk-1 and CREB. Consistent with the increased accumulation of alpha-syn and alterations in mGluR5 in cognitive- and motor-associated brain regions, these mice displayed impaired performance in the water maze and pole test, these behavioral alterations were reversed with the mGluR5 antagonist, MPEP. Taken together the results from study suggest that mGluR5 may directly interact with alpha-syn resulting in its over activation and that this over activation may contribute to excitotoxic cell death in select neuronal regions. These results highlight the therapeutic importance of mGluR5 antagonists in alpha-synucleinopathies.


Assuntos
Doença por Corpos de Lewy/metabolismo , Doenças Neurodegenerativas/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Transdução de Sinais , alfa-Sinucleína/metabolismo , Idoso , Idoso de 80 Anos ou mais , Animais , Autopsia , Encéfalo/metabolismo , Encéfalo/patologia , Encéfalo/fisiopatologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Humanos , Immunoblotting , Imuno-Histoquímica , Doença por Corpos de Lewy/genética , Doença por Corpos de Lewy/patologia , Masculino , Transtornos da Memória/genética , Transtornos da Memória/fisiopatologia , Transtornos da Memória/prevenção & controle , Camundongos , Camundongos Transgênicos , Atividade Motora/efeitos dos fármacos , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/patologia , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Piridinas/farmacologia , Receptor de Glutamato Metabotrópico 5 , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Receptores de Glutamato Metabotrópico/genética , alfa-Sinucleína/genética
18.
Proc Natl Acad Sci U S A ; 103(46): 17513-8, 2006 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-17090684

RESUMO

Reactive astrocytes in neurotrauma, stroke, or neurodegeneration are thought to undergo cellular hypertrophy, based on their morphological appearance revealed by immunohistochemical detection of glial fibrillary acidic protein, vimentin, or nestin, all of them forming intermediate filaments, a part of the cytoskeleton. Here, we used a recently established dye-filling method to reveal the full three-dimensional shape of astrocytes assessing the morphology of reactive astrocytes in two neurotrauma models. Both in the denervated hippocampal region and the lesioned cerebral cortex, reactive astrocytes increased the thickness of their main cellular processes but did not extend to occupy a greater volume of tissue than nonreactive astrocytes. Despite this hypertrophy of glial fibrillary acidic protein-containing cellular processes, interdigitation between adjacent hippocampal astrocytes remained minimal. This work helps to redefine the century-old concept of hypertrophy of reactive astrocytes.


Assuntos
Astrócitos/patologia , Lesões Encefálicas/patologia , Animais , Forma Celular , Feminino , Camundongos
19.
Antimicrob Agents Chemother ; 49(2): 816-9, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15673777

RESUMO

The MICs for 162 diarrheagenic Escherichia coli strains and 28 Shigella strains were determined on the basis of NCCLS guidelines. More than 75% of the strains were resistant to ampicillin, chloramphenicol (53.6% of Shigella strains), and trimethoprim-sulfamethoxazole. Multiresistance was detected in 89.5% of E. coli strains and 78.6% of Shigella strains.


Assuntos
Diarreia/microbiologia , Disenteria Bacilar/microbiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli/efeitos dos fármacos , Shigella/efeitos dos fármacos , Resistência a Ampicilina , Antibacterianos/farmacologia , Criança , Resistência ao Cloranfenicol , Resistência a Medicamentos , Farmacorresistência Bacteriana , Humanos , Testes de Sensibilidade Microbiana , Resistência a Trimetoprima , Combinação Trimetoprima e Sulfametoxazol/farmacologia , Vietnã
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