• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 20
  • 14
  • 4
  • 3
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 50
  • 10
  • 9
  • 9
  • 7
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Avaliação do efeito do inibidor de histona deacetilase Panobinostat (LBH589) no metabolismo energético de células derivadas de câncer de pulmão / Evaluation of effects of histone deacetylase inhibitor Panobinostat (LBH589) on the energy metabolism of lung cancer cell lines

Renan Amphilophio Fernandes 09 July 2015 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Os mecanismos de ação citotóxica do inibidor de histona deacetilase LBH589 foram investigados em associação com o quimioterápico cisplatina (CDDP) em duas linhagens derivadas de câncer de pulmão de não pequenas células (CPNPC). Os resultados foram analisados em relação ao tipo de morte celular associada às alterações em enzimas relacionadas ao metabolismo energético e a via glicolítica. Para realização do trabalho, foram utilizadas as linhagens tumorais A549 (selvagem para o gene de p53) e Calu-1 (nulo para o gene de p53) tratadas com LBH589 em combinação ou não com CDDP. Foram realizadas curvas de tempo e dose-resposta com as drogas isoladamente pelo ensaio de viabilidade celular (MTT) nas duas linhagens para a escolha das melhores condições para o nosso estudo. As condições dos tratamentos isolados com redução da viabilida celular menores que o IC50 de cada fármaco foram selecionados para realização dos tratamentos combinados. As avaliações de apoptose foram realizadas por citometria de fluxo pelo ensaio de Anexina V/PI, e com a marcação de proteínas por Western Blotting. As proteínas relacionadas a via glicolítica foram avaliadas por Western Blotting e a expressão de RNAm por qPCR. Os resultados demonstraram que o LBH589 combinado a CDDP foi capaz de induzir apoptose em 70% das células (Calu-1) e 54,9% (A549) no tempo de 24 horas, e 90% (calu-1) e 62,1% (A549) em 48 horas, independendo, portanto, do status da p53. Os níveis de expressão de enzimas relacionadas com o metabolismos energético também sofreram alterações nos tratamentos estudados. O LBH589 induziu aumento de cerca de 4x dos níveis de RNAm de HK isoformas I e II em ambas as linhagens. Houve também um aumento na expressão proteica das isoformas de HK I e II. Outras enzimas relacionadas a via glicolítica como PFKP, PKM2 e LDHA foram analisadas e apresentaram redução da expressão proteica, principalmente na presença do LBH589. A combinação da CDDP com LBH589 parece ser promissora para o tratamento de CPNPC induzindo apoptose através de alterações no metabolismo energético tumoral. / The cytotoxic mechanisms of action of the histone deacetylase inhibitor LBH589 was investigated in association with cisplatin in two cell lines derived from non-small lung cancer (NSCLC). The results were analyzed based on the type of the cell death associated with alterations in enzymes related to energy metabolism and glycolytic pathway. To perform the study, we used two non-small lung tumor cell lines, A549 (wild type for the p53 gene) and Calu-1 (null for p53 gene) treated with LBH589 in combination with cisplatin or not. Assays for time and dose responses were performed through the cell viability analysis (MTT) for each drug separately in both cell lines to choose the best conditions for our study. The conditions of isolated treatments with reduced viability lower than the IC50 of each drug were selected for carrying out the combined treatments. Assays for apoptosis detection by flow cytometry were performed by Annexin V / PI, the expression of proteins related to apoptosis by Western Blotting. The expression of glycolytic related proteins were performed by Western blotting and their mRNA expressions by qPCR. The results demonstrated that the combined LBH589 plus CDDP was able to induce apoptosis in 70% of cells -Calu-1- and 54.9% -A549- in 24 hours, and 90% (Calu-1) and 62.1 % (A549) in 48 hours regardless of the p53 status. The expression levels of enzymes related to energy metabolism also presented changes in the studied treatments. The LBH589 increase of about 4x the HK isoforms I and II mRNA levels in both cell lines. There was also an increase in the expression isoforms I and II of HK protein. Other enzymes related to the glycolytic pathway as PFKP, PKM2 and LDHA were analyzed and we observed reduced protein expression, especially in the presence of LBH589. The combination of CDDP with LBH589 appears promising for the treatment of NSCLC inducing apoptosis via alterations in energy metabolism tumor.
42

Estudo das interações entre enzimas e polímeros: efeito do poli(etileno glicol) na atividade e na conformação estrutural de enzimas. Adsorção de enzimas sobre superfícies sólidas / Study on the interactions between enzymes and polymers: Influence of polyethylene glycol on the activity and conformation of enzymes. Adsorption of enzymes onto solid surfaces

Sabrina Montero Pancera 10 March 2006 (has links)
Este trabalho visou investigar as interações entre enzimas e polímeros em solução e a adsorção das mesmas sobre superfícies sólidas e para isto foi dividido em duas partes distintas. Na primeira parte a influência do poli(etileno glicol) (PEG), polímero considerado inerte e utilizado em muitos processosbiotecnológicos, na atividade enzimática e na conformação estrutural de enzimas foi estudada através de medidas de espectrofotometria- UV, calorimetria e espalhamento de raio-X de baixo ângulo (SAXS). Foram escolhidas neste estudo as enzimas glicose-6-fosfato desidrogenase (G-6-PDH) e hexoquinase (HK), que são enzimas largamente aplicadas em análises clínicas na determinação de glicose no sangue, e também a enzima álcool desidrogenase (AD), utilizada para determinação de concentração de álcool. Foram obtidos resultados quantitativos, numa faixa de baixa concentração de enzima, que indicam uma forte influência de PEG na atividade das enzimas estudadas. Medidas de calorimetria revelaram que PEG interage não só com a enzima em estudo mas também com a coenzima NADP+. Numa faixa de concentração maior, os resultados de SAXS mostraram que PEG exerce também um efeito significativo no processo de agregação das enzimas. Acima de tudo, foi evidenciado neste estudo que PEG não pode ser tratado como um polímero inerte, pois ele interfere na atividade e conformação de enzimas. As enzimas são macromoléculas complexas e PEG interage de forma diferenciada com cada enzima, merecendo atenção especial caso a caso. Na segunda parte do trabalho, o estudo da adsorção de hexoquinase (HK) e creatina fosfoquinase (CPK) sobre lâminas de silício foi realizado através de medidas de ângulo de contato, elipsometria in situ e microscopia de força atômica (AFM) em água. A CPK é uma enzima bastante utilizada em kits de determinação de creatina no sangue e no diagnóstico de desordens musculares. Este trabalho revelou que o mecanismo de adsorção de CPK sobre silício depende fortemente do pH. Em pH 4, 7 ou 9 CPK adsorveu mantendo a mesma conformação que tinha em solução. Medidas de espectrofotometria UV-Vis revelaram uma mudança no pH ótimo para atividade enzimática de CPK de 6,8 para 9 após adsorção. A HK imobilizada em esferas de vidro mostrou atividade maior do que HK imobilizada nas placas. A reutilização das esferas e placas recobertas com HK foi testada e observou-se que as atividades das enzimas adsorvidas no substrato esférico foram mantidas. Entretanto, nas placas revestidas a atividade foi perdida. As enzimas imobilizadas sobre esferas puderam ser reutilizadas pelo menos 3 vezes, mantendo a atividade por um período de até 3 semanas. / This work aimed to investigate the interactions between enzymes and polymers in solution and also the adsorption behavior of these enzymes on solid surfaces. For that reason it was divided into two parts. In the first part, the influence of poly(ethylene glycol) (PEG), a polymer considered inert and utilized in several biotechnological processes, on the enzymatic activity and structure of the enzyme was studied by means of UV spectrophotometry, calorimetric titration, circular dichroism (CD) and small angle X-ray scattering (SAXS). Glucose-6-phosphate dehydrogenase (G-6-PDH) and hexokinase (HK) were chosen because of their large application in clinical analysis for determination of glucose in the blood strain. Alcohol dehydrogenase (AD), which is widely used to determine alcohol concentration in various samples, was also used. Quantitative results, in a low enzyme concentration range, indicated a strong influence of PEG on the enzymes activity. The calorimetric measurements revealed no favorable interactions between enzyme and polymer, but indicated favorable interactions between PEG and co-enzyme NADP+. In a higher concentration range, SAXS results showed that PEG also exerts a significant effect on the enzyme aggregation process. This work showed that PEG shall no longer be treated as an inert polymer since it interferes in the enzyme activity and structure. The enzymes are complex macromolecules and PEG interacts differently with each one, deserving special attention in each case. In the second part of the work, the adsorption behavior of creatine phosphokinase (CPK) and hexokinase (HK) onto silicon wafers was studied by means of contact angle measurements, in situ ellipsometry and atomic force microscopy (AFM) in water. CPK was chosen due to its large application on the diagnosis of several muscle disorders. This work revealed that the adsorption mechanism of CPK on silicon surfaces is strongly dependent on pH. At pH 4, 6.8 or 9, CPK adsorbed keeping the same conformation as in solution. pectrophotometric measurements revealed a shift on the optimum pH from 6,8 to 9 upon CPK adsorption. HK adsorbed onto glass beads showed higher activity than HK immobilized on silicon wafers. HK covered glass beads could also be reused three times and for a period of at least three weeks. In the contrary, HK covered silicon wafers could not be reused. For practical purposes, HK covered glass beads showed to be a better “biosensor” than HK covered silicon wafers.
43

Signals Delivered By Interleukin-7 Regulate The Activities Of Bim And Jund In T Lymphocytes

Ruppert, Shannon Moore 01 January 2012 (has links)
Interleukin-7 (IL-7) is an essential cytokine for lymphocyte growth that has the potential for promoting proliferation and survival. While the survival and proliferative functions of IL-7 are well established, the identities of IL-7 signaling components in pathways other than JAK/STAT, that accomplish these tasks remain poorly defined. To this end, we used IL-7 dependent T-cells to examine those components necessary for cell growth and survival. Our studies revealed two novel signal transducers of the IL-7 growth signal: BimL and JunD. IL-7 promoted the activity of JNK (Jun N-terminal Kinase), and that JNK, in turn, drove the expression of JunD, a component of the Activating Protein 1 (AP-1) transcription factors. Inhibition of JNK/JunD blocked glucose uptake and HXKII gene expression, indicating that this pathway was responsible for promoting HXKII expression. After a bioinformatics survey to reveal possible JunD-regulated genes activated early in the IL-7 signaling cascade, our search revealed that JunD could control the expression of proteins involved in signal transduction, cell survival and metabolism, including Pim-1. Pim-1, an IL-7 induced protein, was inhibited upon JNK or JunD inhibition. Our hypothesis that JunD positively regulated proliferation was confirmed when the proliferation of primary CD8+ T-cells cultured with IL-7 was impaired upon treatment with JunD siRNA. These results show that the IL-7 signal is more complex than the JAK/STAT pathway, activating JNK and JunD to induce rapid growth through the expression of metabolic factors like HXKII and Pim-1. When metabolic activities are inhibited, cells undergo autophagy, or cell scavenging, to provide essential nutrients. Pro-apoptotic Bim was evaluated for its involvement in autophagy. Bim is a BH3-only member of the Bcl-2 family that contributes to T-cell death. Partial rescue of iv T-cells occurs when Bim and the interleukin-7 receptor are deleted, implicating Bim in IL-7- deprived T-cell apoptosis. Alternative splicing results in three different isoforms: BimEL, BimL, and BimS. To study the effect of Bim deficiency and define the function of the major isoforms, Bim-containing and Bim-deficient T-cells, dependent on IL-7 for growth, were used. Loss of Bim in IL-7-deprived T-cells delayed apoptosis, but blocked the degradative phase of autophagy. The conversion of LC3-I to LC3-II was observed in Bim-deficient T-cells, but p62, which is degraded in autolysosomes, accumulated. To explain this, BimL, was found to support acidification of lysosomes associated with autophagic vesicles. Key findings showed that inhibition of lysosomal acidification accelerated death upon IL-7 withdrawal only in Bimcontaining T-cells, indicating that in these cells autophagy was protective. IL-7 dependent Tcells lacking Bim were insensitive to inhibition of autophagy or lysosomal acidification. BimL co-immunoprecipitated with dynein and Lamp1-containing vesicles, indicating BimL could be an adaptor for dynein to facilitate loading of lysosomes. In Bim deficient T-cells, lysosometracking probes revealed vesicles of less acidic pH. Over-expression of BimL restored acidic vesicles in Bim deficient T-cells, while other isoforms, BimEL and BimS, associated with intrinsic cell death. These results reveal a novel role for BimL in lysosomal positioning that may be required for the formation of functional autolysosomes during autophagy
44

Carbon metabolism in transgenic roots with altered levels of hexokinase and triosephosphate isomerase and growing under different nitrogen status

Sedaghatkish, Afsaneh 01 1900 (has links)
Ce projet a pour but d’évaluer la capacité de la voie des pentoses phosphates (VPP) dans les racines transgéniques de pomme de terre (Solanum tuberosum) modifiées pour exprimer différents niveaux de l'hexokinase (HK) et de la triosephosphate isomérase cytosolique (cTPI). Dans les racines, la VPP alimente la voie de l’assimilation de l’azote en equivalents réducteurs et permet donc la biosynthèse des acides aminés. Le glucose-6-phosphate produit par l’HK est consommé par la partie oxydative de la VPP catalysée par la glucose-6-phosphate déshydrogénase (G6PDH) et la 6-phosphogluconate déshydrogénase (6PGDH). Les changements dans l'expression de HK et cTPI peuvent affecter le fonctionnement de la VPP et les mécanismes qui sont liés à l’utilisation des équivalents réducteurs produits par la VPP, comme l'assimilation de l’azote et la synthèse des acides aminés. Afin d’évaluer l’effet des manipulations génétiques de l’HK et de la cTPI sur l’assimilation de l’azote, nous avons cultivé les racines transgéniques sur des milieux contenant des concentrations élevées (7 mM) ou basses (0,7 mM) de nitrate d’ammonium comme source d’azote. Les résultats montrent que la culture sur un milieu riche en azote induit les activités G6PDH et 6PGDH. Les données montrent que la capacité de la VPP est plus grande avec des niveaux élevés en HK ou en cTPI. Nous avons aussi pu démontrer une plus grande activité spécifique de l’HK dans les conditions pauvres en azote. Ces données ont été complémentées par des mesures des pools d’acides aminés dans les racines transgéniques cultivées sur différents niveaux d’azote. Aucune tendance notable des pools d’acides aminés n’a été remarquée dans les racines modifiées pour leur contenu en HK suggèrant que la manipulation de HK n’affecte pas l'assimilation de l’azote. Dans les racines transgéniques modifiées pour la cTPI, les ratios Gln/Glu et Asn/Asp sont plus élevés chez les clones antisens, indiquant une assimilation de l’azote plus élevée. Ces résultats ont démontré l'activation de l'assimilation de l’azote chez les clones antisens cTPI dans les conditions élevées et basses d’azote alors que la manipulation de l’HK n’affecte pas l’assimilation de l’azote. / This study investigates the capacity of the oxidative pentose phosphate pathway (oxPPP) and nitrogen metabolism in transgenic potato (Solanum tuberosum) roots modified to express different levels of hexokinase (HK) or cytosolic triosephosphate isomerase (cTPI) growing under different nitrogen regimes. The flux of carbon through the oxPPP in cTPI antisense roots is higher than control roots growing under high supply of N. On the other hand, the conversion of Glucose (Glc) to Glucose-6-phosphate (G6P) is higher in roots overexpressing HK than in antisense HK roots growing at a high level of N. Therefore, overexpression of HK or down regulation of cTPI activities in transgenic roots might be compensated by increased C catabolism through the oxPPP. In order to see the affect of HK and cTPI manipulation on N assimilation, the transgenic roots were grown on media with low or high concentration of ammonium nitrate as the N source. The specific activity of the oxPPP enzymes glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were both increased by an increased N supply in HK and cTPI transgenic roots. This is consistent with the provision of reducing equivalents for N assimilation. The data also show that the capacity of the oxPPP is higher in roots with high HK or cTPI activity. We were able to detect higher HK specific activity in N deficient conditions. These data were complemented with measurements of amino acid pools in transgenic roots. No trend in amino acid pools was found in roots modified for HK activity. However, down regulation of cTPI led to higher Gln, Gln/Glu and Asn/Asp ratios, indicating higher assimilation of N. These results demonstrated the activation of N assimilation in cTPI antisense clones while the manipulation of HK is unlikely to affect the N assimilation.
45

Alterações em genes relacionados à via glicolítica em tumores de carcinoma epidermoide de esôfago / Alterations in genes involved in glycolysis in esophageal squamous cell carcinoma

Ester de Andrade Barreto 07 March 2013 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / O carcinoma epidermoide de esôfago (CEE) representa 90% dos casos de câncer de esôfago no Brasil. O CEE tem detecção tardia, um comportamento extremamente agressivo e baixa sobrevida, sendo, portanto, um alvo interessante para o estudo dos mecanismos envolvidos em sua carcinogênese, a fim de se identificar possíveis alvos terapêuticos ou marcadores moleculares que ajudem na prática clínica. Mudanças no metabolismo energético da célula tumoral parecem ter papel de destaque na transformação maligna. Sabe-se que células tumorais consomem glicose avidamente produzindo ácido lático, mesmo em condições de normóxia. Dentre os fatores que podem contribuir para o estímulo da glicólise em células tumorais destacam-se as alterações em enzimas da via glicolítica tais como: as piruvato-cinases M1 e M2 (PKM1 e PKM2), a hexocinase II (HKII), isofoma 1 do transportador de glicose, GLUT-1, e o fator de transcrição induzido por hipóxia (HIF1α), responsável pela transcrição das proteínas citadas. O objetivo do estudo é avaliar a relação entre a expressão de HIF1α, HK2, PKM2, PKM1 e GLUT-1 e dados clínico-patológicos no CEE. Para tal, foram avaliados tumores conservados em parafina de 44 pacientes com CEE matriculados no INCA e no Hospital das Clínicas de Porto Alegre. Além disso, foram coletadas amostras de biópsia de esôfago em 67 pacientes sem doença esofágica, que foram submetidos à endoscopia no Hospital Universitário Pedro Ernesto (HUPE). A expressão das proteínas foi avaliada nos tecidos por imuno-histoquímica, enquanto que a expressão do mRNA de GLUT-1 também foi avaliada nas amostras controle. Foi observado que as amostras controle expressam HK2, PKM1, PKM2, HIF1α nas camadas do epitélio esofágico. Já GLUT-1 e Ki-67 são vistos apenas na camada basal. Além disso, a expressão do mRNA de GLUT-1 não teve correlação com fatores etiológicos da doença. Em CEE a expressão de HK2, PKM2 e GLUT-1 foi vista em todos os tumores, já a expressão de HIF1α e PKM1 foi variável. Além disso, observou-se que maior expressão de HIF-1α apresenta correlação com invasão linfonodal e diferenciação, enquanto que a expressão de HK2 tem relação com sobrevida e PKM1 com diferenciação. As correlações clínicas encontradas sugerem que alterações no metabolismo energético é um alvo de estudo interessante para desenvolvimento de marcadores moleculares que auxiliem a prática clínica. / The esophageal squamous cell carcinoma (ESCC) represents 90% of cases of esophageal cancer in Brazil. The ESCC has late diagnosis, highly aggressive behavior and poor survival. ESCC is an interesting target to the study of mechanism involved in its carcinogenesis, in order to identify potential drug targets or biomarkers to help clinical practice. Changes in tumor cell energy metabolism appear to have a prominent role in malignant transformation. Tumor cells consume glucose avidly and produce lactic acid, even under normoxia. Among the factors that may contribute to the stimulation of glycolysis in tumor cells, there are changes in the glycolytic pathway enzymes such as: pyruvate kinase M1 and M2 (PKM2 and PKM1), hexokinase II (HKII), glucose transporter isoform 1, GLUT-1, and transcription factor induced by hypoxia (HIF1α), responsible for the transcription of proteins cited. The goal of the study is to evaluate the relationship between the expression of HIF1α, HK2, PKM2, PKM1 and GLUT-1 and clinicopathological data in ESCC. Biopsy of the esophagus in patients without esophageal disease were collected, who underwent endoscopy at University Hospital Pedro Ernesto (HUPE). Tissue samples were collected from 44 patients with a histologically confirmed diagnosis of ESCC recruted from Hospital Universitário Pedro Ernesto (HUPE-UERJ), and Instituto Nacional de Câncer (INCA). Tissue samples from healthy individuals submitted to endoscopic routine examination, not related to cancer or esophageal disorders, at HUPE-UERJ were also included in this study. The expression of proteins in tissues was evaluated by immunohistochemistry, while mRNA expression of GLUT-1 was also evaluated in the control samples. It was observed that the control samples express HK2, PKM1, PKM2, HIF1α layers of the esophageal epithelium. GLUT-1 and Ki-67 are seen only in the basal layer. Furthermore, expression of GLUT-1 mRNA did not correlate with disease etiological factors. In ESCC expression of HK2, PKM2 and GLUT-1 was seen in all tumors, and the expression of HIF1α and PKM1 was variable. We found that increased expression of HIF-1α correlates with lymph node invasion and differentiation, whereas the expression of HK2 is related to survival, and differentiation with PKM1. The clinical correlations found suggest that alterations in energy metabolism are an interesting subject of study for development of biomarkers that help clinical practice.
46

Carbon metabolism in transgenic roots with altered levels of hexokinase and triosephosphate isomerase and growing under different nitrogen status

Sedaghatkish, Afsaneh 01 1900 (has links)
Ce projet a pour but d’évaluer la capacité de la voie des pentoses phosphates (VPP) dans les racines transgéniques de pomme de terre (Solanum tuberosum) modifiées pour exprimer différents niveaux de l'hexokinase (HK) et de la triosephosphate isomérase cytosolique (cTPI). Dans les racines, la VPP alimente la voie de l’assimilation de l’azote en equivalents réducteurs et permet donc la biosynthèse des acides aminés. Le glucose-6-phosphate produit par l’HK est consommé par la partie oxydative de la VPP catalysée par la glucose-6-phosphate déshydrogénase (G6PDH) et la 6-phosphogluconate déshydrogénase (6PGDH). Les changements dans l'expression de HK et cTPI peuvent affecter le fonctionnement de la VPP et les mécanismes qui sont liés à l’utilisation des équivalents réducteurs produits par la VPP, comme l'assimilation de l’azote et la synthèse des acides aminés. Afin d’évaluer l’effet des manipulations génétiques de l’HK et de la cTPI sur l’assimilation de l’azote, nous avons cultivé les racines transgéniques sur des milieux contenant des concentrations élevées (7 mM) ou basses (0,7 mM) de nitrate d’ammonium comme source d’azote. Les résultats montrent que la culture sur un milieu riche en azote induit les activités G6PDH et 6PGDH. Les données montrent que la capacité de la VPP est plus grande avec des niveaux élevés en HK ou en cTPI. Nous avons aussi pu démontrer une plus grande activité spécifique de l’HK dans les conditions pauvres en azote. Ces données ont été complémentées par des mesures des pools d’acides aminés dans les racines transgéniques cultivées sur différents niveaux d’azote. Aucune tendance notable des pools d’acides aminés n’a été remarquée dans les racines modifiées pour leur contenu en HK suggèrant que la manipulation de HK n’affecte pas l'assimilation de l’azote. Dans les racines transgéniques modifiées pour la cTPI, les ratios Gln/Glu et Asn/Asp sont plus élevés chez les clones antisens, indiquant une assimilation de l’azote plus élevée. Ces résultats ont démontré l'activation de l'assimilation de l’azote chez les clones antisens cTPI dans les conditions élevées et basses d’azote alors que la manipulation de l’HK n’affecte pas l’assimilation de l’azote. / This study investigates the capacity of the oxidative pentose phosphate pathway (oxPPP) and nitrogen metabolism in transgenic potato (Solanum tuberosum) roots modified to express different levels of hexokinase (HK) or cytosolic triosephosphate isomerase (cTPI) growing under different nitrogen regimes. The flux of carbon through the oxPPP in cTPI antisense roots is higher than control roots growing under high supply of N. On the other hand, the conversion of Glucose (Glc) to Glucose-6-phosphate (G6P) is higher in roots overexpressing HK than in antisense HK roots growing at a high level of N. Therefore, overexpression of HK or down regulation of cTPI activities in transgenic roots might be compensated by increased C catabolism through the oxPPP. In order to see the affect of HK and cTPI manipulation on N assimilation, the transgenic roots were grown on media with low or high concentration of ammonium nitrate as the N source. The specific activity of the oxPPP enzymes glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were both increased by an increased N supply in HK and cTPI transgenic roots. This is consistent with the provision of reducing equivalents for N assimilation. The data also show that the capacity of the oxPPP is higher in roots with high HK or cTPI activity. We were able to detect higher HK specific activity in N deficient conditions. These data were complemented with measurements of amino acid pools in transgenic roots. No trend in amino acid pools was found in roots modified for HK activity. However, down regulation of cTPI led to higher Gln, Gln/Glu and Asn/Asp ratios, indicating higher assimilation of N. These results demonstrated the activation of N assimilation in cTPI antisense clones while the manipulation of HK is unlikely to affect the N assimilation.
47

Alterações em genes relacionados à via glicolítica em tumores de carcinoma epidermoide de esôfago / Alterations in genes involved in glycolysis in esophageal squamous cell carcinoma

Ester de Andrade Barreto 07 March 2013 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / O carcinoma epidermoide de esôfago (CEE) representa 90% dos casos de câncer de esôfago no Brasil. O CEE tem detecção tardia, um comportamento extremamente agressivo e baixa sobrevida, sendo, portanto, um alvo interessante para o estudo dos mecanismos envolvidos em sua carcinogênese, a fim de se identificar possíveis alvos terapêuticos ou marcadores moleculares que ajudem na prática clínica. Mudanças no metabolismo energético da célula tumoral parecem ter papel de destaque na transformação maligna. Sabe-se que células tumorais consomem glicose avidamente produzindo ácido lático, mesmo em condições de normóxia. Dentre os fatores que podem contribuir para o estímulo da glicólise em células tumorais destacam-se as alterações em enzimas da via glicolítica tais como: as piruvato-cinases M1 e M2 (PKM1 e PKM2), a hexocinase II (HKII), isofoma 1 do transportador de glicose, GLUT-1, e o fator de transcrição induzido por hipóxia (HIF1α), responsável pela transcrição das proteínas citadas. O objetivo do estudo é avaliar a relação entre a expressão de HIF1α, HK2, PKM2, PKM1 e GLUT-1 e dados clínico-patológicos no CEE. Para tal, foram avaliados tumores conservados em parafina de 44 pacientes com CEE matriculados no INCA e no Hospital das Clínicas de Porto Alegre. Além disso, foram coletadas amostras de biópsia de esôfago em 67 pacientes sem doença esofágica, que foram submetidos à endoscopia no Hospital Universitário Pedro Ernesto (HUPE). A expressão das proteínas foi avaliada nos tecidos por imuno-histoquímica, enquanto que a expressão do mRNA de GLUT-1 também foi avaliada nas amostras controle. Foi observado que as amostras controle expressam HK2, PKM1, PKM2, HIF1α nas camadas do epitélio esofágico. Já GLUT-1 e Ki-67 são vistos apenas na camada basal. Além disso, a expressão do mRNA de GLUT-1 não teve correlação com fatores etiológicos da doença. Em CEE a expressão de HK2, PKM2 e GLUT-1 foi vista em todos os tumores, já a expressão de HIF1α e PKM1 foi variável. Além disso, observou-se que maior expressão de HIF-1α apresenta correlação com invasão linfonodal e diferenciação, enquanto que a expressão de HK2 tem relação com sobrevida e PKM1 com diferenciação. As correlações clínicas encontradas sugerem que alterações no metabolismo energético é um alvo de estudo interessante para desenvolvimento de marcadores moleculares que auxiliem a prática clínica. / The esophageal squamous cell carcinoma (ESCC) represents 90% of cases of esophageal cancer in Brazil. The ESCC has late diagnosis, highly aggressive behavior and poor survival. ESCC is an interesting target to the study of mechanism involved in its carcinogenesis, in order to identify potential drug targets or biomarkers to help clinical practice. Changes in tumor cell energy metabolism appear to have a prominent role in malignant transformation. Tumor cells consume glucose avidly and produce lactic acid, even under normoxia. Among the factors that may contribute to the stimulation of glycolysis in tumor cells, there are changes in the glycolytic pathway enzymes such as: pyruvate kinase M1 and M2 (PKM2 and PKM1), hexokinase II (HKII), glucose transporter isoform 1, GLUT-1, and transcription factor induced by hypoxia (HIF1α), responsible for the transcription of proteins cited. The goal of the study is to evaluate the relationship between the expression of HIF1α, HK2, PKM2, PKM1 and GLUT-1 and clinicopathological data in ESCC. Biopsy of the esophagus in patients without esophageal disease were collected, who underwent endoscopy at University Hospital Pedro Ernesto (HUPE). Tissue samples were collected from 44 patients with a histologically confirmed diagnosis of ESCC recruted from Hospital Universitário Pedro Ernesto (HUPE-UERJ), and Instituto Nacional de Câncer (INCA). Tissue samples from healthy individuals submitted to endoscopic routine examination, not related to cancer or esophageal disorders, at HUPE-UERJ were also included in this study. The expression of proteins in tissues was evaluated by immunohistochemistry, while mRNA expression of GLUT-1 was also evaluated in the control samples. It was observed that the control samples express HK2, PKM1, PKM2, HIF1α layers of the esophageal epithelium. GLUT-1 and Ki-67 are seen only in the basal layer. Furthermore, expression of GLUT-1 mRNA did not correlate with disease etiological factors. In ESCC expression of HK2, PKM2 and GLUT-1 was seen in all tumors, and the expression of HIF1α and PKM1 was variable. We found that increased expression of HIF-1α correlates with lymph node invasion and differentiation, whereas the expression of HK2 is related to survival, and differentiation with PKM1. The clinical correlations found suggest that alterations in energy metabolism are an interesting subject of study for development of biomarkers that help clinical practice.
48

The multifactorial regulation of the immune checkpoint PD-L1 in the course of H. pylori infection

Sigulla, Janine 18 March 2021 (has links)
Eines der prävalentesten humanen Pathogene ist das Magenbakterium Helicobacter pylori, welches ca. die Hälfte der Weltbevölkerung infiziert. Die Persistenz geht mit einer chronischen Gastritis einher, welche bis zu Magenkrebs fortschreiten kann. H.pylori bedient sich diverser Mechanismen um sich der Erkennung des Immunsystems zu entziehen und somit eine chronische Infektion zu ermöglichen. Erhöhte Expression des Immunzellinhibitors PD-L1 wurde in Magenepithelzellen gefunden, welche mit diesem Gram-negativen Erreger infiziert wurden. In dieser Arbeit wurde die Regulation auf in vitro Ebene untersucht, wobei zwei unterschiedliche Mechanismen identifiziert wurden. Ursächlich für die frühe PD-L1-Induktion ist die ADP-heptose/ALPK1 Signalkaskade. Der bakterielle Metabolit ADP-heptose, welcher für die Bildung von LPS benötigt wird, wurde als PAMP identifiziert, welcher durch das Sekretionssystems cagT4SS in die infizierte transportiert und anschließend von der Host Kinase ALPK1 erkannt wird. Gegensätzlich hierzu, wurde festgestellt, dass die zweite PD-L1-Hochregulation auf der metabolischen Reprogrammierung des Wirts beruht. Ein Merkmal von H. pylori ist dessen Bedarf an Cholesterin, welches es aus dem Medium oder aus membranösen Lipidregionen des Wirts extrahiert wird. Es konnte bewiesen werden, dass dieser Sterol-Abbauprozess zu einer erhöhten Stoffwechselaktivität führt, die spezifisch mit einer Zunahme der Glykolyse verbunden ist und mit einer Expressionsverschiebung des ersten Glykolyseenzyms Hexokinase von der Isoform 1 zu 2 einhergeht. Knockdown und Knockout- Experimente wiesen auf einen Zusammenhang mit der Regulation des Immunzellinhibitoren PD-L1 hin. / One of the most prevalent bacteria is the gastric bacterium Helicobacter pylori, which infects half of the world’s population. Persistence is accompanied with chronic gastritis which can progress towards gastric cancer. Several strategies are used by H.pylori to evade the immune system, enabling chronic infection. Heightened expression of the immune cell inhibitor PD-L1 was found in gastric epithelial cells, infected with this Gram-negative pathogen. Within this thesis, upregulation was studied in in vitro models, revealing two distinct mechanism. Causative for early PD-L1 induction is the ADP heptose/ALPK1 signaling axis. The bacterial metabolite ADP heptose, which is needed for LPS synthesis, was identified as PAMP, which is transported through the secretion system cagT4SS into the infected cell and is recognized by the host kinase ALPK1. In contrast, late upregulation of PD-L1 was found to be linked to metabolic reprogramming upon infection. Characteristic to H.pylori is its need of cholesterol, which it has to extract from the surrounding medium or lipid-rich regions within the host membrane. It could be shown that this sterol extraction process is accompanied with an increased metabolic activity which is linked with enhanced glycolysis and an expression shift of the glycolytic enzyme hexokinase isoform 1 to 2. Knockdown and knockout experiments showed a link between HK2 and regulation of the immune checkpoint PD-L1.
49

Correlação da expressão de GLUT1, HK1, HK2 e HK3 com alta captação de 18/F-FDG em hiperplasia macronodular adrenal primária / Correlation between GLUT1, HK1, HK2 and HK3 expression and high 18F-FDG uptake in primary macronodular adrenal hyperplasia

Cavalcante, Isadora Pontes 03 October 2014 (has links)
Introdução: Hiperplasia Macronodular Adrenal Primária (PMAH) é uma causa rara de Síndrome de Cushing (SC), caracterizada por macronódulos funcionantes geralmente acometendo ambas as glândulas adrenais. Recentemente, o exame 18F-FDG PET/CT detectou três pacientes com PMAH apresentando captação aumentada de 18F-FDG. No entanto, ainda não foi elucidado o mecanismo pelo qual a PMAH apresentaria uma alta captação de 18F-FDG. Objetivos: Os objetivos deste estudo foram investigar se a expressão de GLUT1, HK1, HK2 e/ou HK3 estão relacionados à alta captação de 18F-FDG na PMAH e comparar estas expressões com tecidos adrenais provenientes de pacientes com AAC e CAA. Métodos: 12 pacientes com PMAH que realizaram 18F-FDG-PET/CT, previamente à adrenalectomia. A captação de 18F-FDG foi quantificada como maximum standardized uptake value (SUVmax). Expressão do RNAm foi investigada através de RT-PCR e a expressão proteica através de técnicas de imunoistoquímica. Expressão gênica e proteica dos pacientes com PMAH foi comparada com 15 pacientes com AAC e 10 pacientes com CAA. As correlações foram realizadas através do teste de coeficiente de correlação de Pearson e as comparações, através do teste Kruskal-Wallis, seguido do ajuste de Dunn. Significância estatística foi considerada quando p < 0.05. Resultados: Todos os pacientes com PMAH apresentaram alta captação de 18F-FDG, cujo SUVmáx variou de 3.3 a 8.9 e o tamanho do maior nódulo variou de 3.5 a 15cm. Foi observada forte correlação positiva entre o tamanho do maior nódulo e o SUVmáx nos pacientes com PMAH. No entanto, não foi estabelecida correlação entre a expressão de GLUT1, HK1, HK2 e HK3 e o SUVmáx nos pacientes com PMAH. A expressão do SLC2A1 e HK2 foi significativamente maior nos pacientes com CAA do que nos pacientes com AAC e PMAH. Conclusões: A captação aumentada de 18F-FDG na PMAH não está relacionada ao aumento da expressão de GLUT1, HK1, HK2 e HK3. Estudos futuros serão necessários para elucidar a via glicolítica que é responsável pelo metabolismo da glicose na PMAH / Introduction: Primary macronodular adrenal hyperplasia (PMAH) is a rare cause of Cushing\'s syndrome, characterized by functioning adrenal macronodules and increased cortisol production. Recently, integrated 18F-FDG-PET/CT examination revealed an increased 18F-FDG uptake in patients with PMAH. However, it is still unclear the mechanism by which PMAH would present with a high 18F-FDG uptake in PET/CT. Objectives: The aim of this study was to investigate whether GLUT1, HK1, HK2 and/or HK3 expression would account for the high18F-FDG uptake in PMAH and compare these expressions with ACA and ACC adrenal tisuue. Methods: 12 patients undergoing adrenalectomy for PMAH with previous 18F-FDG-PET/CT. 18F-FDG uptake was quantified as the maximum standardized uptake value (maxSUV). mRNA expression was investigated through quantitative RT-PCR and protein expression was investigated using immunohistochemical studies. PMAH gene and protein expression were compared to 15 patients with ACA and 10 with ACC. Correlations were performed through Pearson\'s correlation coefficient test and comparisons through Kruskal-Wallis test, followed by Dunn adjust. Statistical significance was considered when p < 0.05. Results: All patients with PMAH presented with high 18F-FDG uptake, the range of SUVmax in these patients varied from 3.3 to 8.9 and the nodule sizes varied from 3.5 to 15 cm. There was a strong positive correlation between the nodule size and 18F-FDG uptake. However, no correlation could be established between gene and protein expression of GLUT1, HK1, HK2 and HK3 and 18F-FDG uptake. SLC2A1 and HK2 expression was significantly higher in patients with CCA than in patients with AAC and PMAH. Conclusions: Increased 18F-FDG uptake in PMAH does not arise from the overexpression of GLUT1, HK1, HK2 or HK3. Further investigation is required to elucidate the glycolytic pathway involved in glucose metabolism in PMAH
50

Correlação da expressão de GLUT1, HK1, HK2 e HK3 com alta captação de 18/F-FDG em hiperplasia macronodular adrenal primária / Correlation between GLUT1, HK1, HK2 and HK3 expression and high 18F-FDG uptake in primary macronodular adrenal hyperplasia

Isadora Pontes Cavalcante 03 October 2014 (has links)
Introdução: Hiperplasia Macronodular Adrenal Primária (PMAH) é uma causa rara de Síndrome de Cushing (SC), caracterizada por macronódulos funcionantes geralmente acometendo ambas as glândulas adrenais. Recentemente, o exame 18F-FDG PET/CT detectou três pacientes com PMAH apresentando captação aumentada de 18F-FDG. No entanto, ainda não foi elucidado o mecanismo pelo qual a PMAH apresentaria uma alta captação de 18F-FDG. Objetivos: Os objetivos deste estudo foram investigar se a expressão de GLUT1, HK1, HK2 e/ou HK3 estão relacionados à alta captação de 18F-FDG na PMAH e comparar estas expressões com tecidos adrenais provenientes de pacientes com AAC e CAA. Métodos: 12 pacientes com PMAH que realizaram 18F-FDG-PET/CT, previamente à adrenalectomia. A captação de 18F-FDG foi quantificada como maximum standardized uptake value (SUVmax). Expressão do RNAm foi investigada através de RT-PCR e a expressão proteica através de técnicas de imunoistoquímica. Expressão gênica e proteica dos pacientes com PMAH foi comparada com 15 pacientes com AAC e 10 pacientes com CAA. As correlações foram realizadas através do teste de coeficiente de correlação de Pearson e as comparações, através do teste Kruskal-Wallis, seguido do ajuste de Dunn. Significância estatística foi considerada quando p < 0.05. Resultados: Todos os pacientes com PMAH apresentaram alta captação de 18F-FDG, cujo SUVmáx variou de 3.3 a 8.9 e o tamanho do maior nódulo variou de 3.5 a 15cm. Foi observada forte correlação positiva entre o tamanho do maior nódulo e o SUVmáx nos pacientes com PMAH. No entanto, não foi estabelecida correlação entre a expressão de GLUT1, HK1, HK2 e HK3 e o SUVmáx nos pacientes com PMAH. A expressão do SLC2A1 e HK2 foi significativamente maior nos pacientes com CAA do que nos pacientes com AAC e PMAH. Conclusões: A captação aumentada de 18F-FDG na PMAH não está relacionada ao aumento da expressão de GLUT1, HK1, HK2 e HK3. Estudos futuros serão necessários para elucidar a via glicolítica que é responsável pelo metabolismo da glicose na PMAH / Introduction: Primary macronodular adrenal hyperplasia (PMAH) is a rare cause of Cushing\'s syndrome, characterized by functioning adrenal macronodules and increased cortisol production. Recently, integrated 18F-FDG-PET/CT examination revealed an increased 18F-FDG uptake in patients with PMAH. However, it is still unclear the mechanism by which PMAH would present with a high 18F-FDG uptake in PET/CT. Objectives: The aim of this study was to investigate whether GLUT1, HK1, HK2 and/or HK3 expression would account for the high18F-FDG uptake in PMAH and compare these expressions with ACA and ACC adrenal tisuue. Methods: 12 patients undergoing adrenalectomy for PMAH with previous 18F-FDG-PET/CT. 18F-FDG uptake was quantified as the maximum standardized uptake value (maxSUV). mRNA expression was investigated through quantitative RT-PCR and protein expression was investigated using immunohistochemical studies. PMAH gene and protein expression were compared to 15 patients with ACA and 10 with ACC. Correlations were performed through Pearson\'s correlation coefficient test and comparisons through Kruskal-Wallis test, followed by Dunn adjust. Statistical significance was considered when p < 0.05. Results: All patients with PMAH presented with high 18F-FDG uptake, the range of SUVmax in these patients varied from 3.3 to 8.9 and the nodule sizes varied from 3.5 to 15 cm. There was a strong positive correlation between the nodule size and 18F-FDG uptake. However, no correlation could be established between gene and protein expression of GLUT1, HK1, HK2 and HK3 and 18F-FDG uptake. SLC2A1 and HK2 expression was significantly higher in patients with CCA than in patients with AAC and PMAH. Conclusions: Increased 18F-FDG uptake in PMAH does not arise from the overexpression of GLUT1, HK1, HK2 or HK3. Further investigation is required to elucidate the glycolytic pathway involved in glucose metabolism in PMAH

Page generated in 0.0525 seconds