940 resultados para Aniline methylation
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O câncer de mama é o tipo de neoplasia que mostra as maiores taxas de mortalidade entre as mulheres no Brasil, provavelmente pelo fato de que, na maioria dos casos, a doença é diagnosticada em estadios avançados, dificultando o sucesso do tratamento. Dessa forma, essa doença é considerada um problema crítico de saúde pública. O câncer é uma doença que se caracteriza por sucessivas alterações genéticas e epigenéticas que causam um crescimento e multiplicação celular desordenados. A hipermetilação da região promotora de genes específicos pode levar ao silenciamento gênico, um evento importante no processo da carcinogênese. Este estudo analisou o padrão de metilação da isoforma RASSF1A do gene RASSF1 em linhagens celulares derivadas de carcinoma mamário. Esse gene está mapeado na região cromossômica 3p21.3 e, segundo dados da literatura, atua como supressor tumoral. O principal objetivo desse estudo foi investigar a presença de hipermetilação na região promotora desse gene em linhagens celulares de carcinomas mamários. Para a realização dessa análise foi empregada a metodologia de MSP (Methylation-specific Polymerase Chain Reaction) convencional e de qMSP (Methylation-Specific Polymerase Chain Reaction quantitativa em tempo real). Todas as linhagens de carcinomas mamários analisadas no estudo (MCF7, MDA-MB-231, MDA-MB-453, MDA-MB-134 e SKBR3) apresentaram um padrão hipermetilado na região promotora do gene RASSF1 corroborando com dados da literatura que relacionam a inativação desse gene à hipermetilação do promotor. Estes dados, associados aos obtidos em uma análise paralela realizada em nosso laboratório que demonstrou a re-expressão do gene RASSF1 após o tratamento com o agente desmetilante 5 aza 2’desoxicitidina, confirmam a regulação epigenética desse gene supressor tumoral
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Breast cancer has received an increasing attention because it is one of the most common cancer type and a leading cause of morbity and mortality among women worldwide. This disease has been considered as a heterogeneous condition, demonstrating a large spectrum of clinical and histopathological variability. In the last two decades, several studies have been conducted to identify new molecular markers of cancer cells, including the alterations of DNA methylation, which is the major epigenetic mechanism associated with the control of gene expression. The hypermethylation of promoter-associated CpG islands contributes to the loss of function of several cancer-related genes, including those encoding to the estrogen receptor (ESR) and progesterone receptor (PGR). This study aimed to determine the methylation patterns of CpG islands of the genes encoding the estrogen receptor α (ESR1 gene, promoters A and B), estrogen receptor β (ESR2 gene) and progesterone receptor (PGR gene, promoter A and B) in 15 cell lines derived from breast cancer. The DNA methylation analysis was based on the “Methylation Specific-Polymerase Chain Reaction” (MSP), which provides a qualitative assessment of the methylation status of a specific CpG island. The results revealed heterogeneous data: the promoter region of ESR1A showed complete methylation in one cell line (BT549) and only two cell lines showed partial methylation (MDA-MB-231 and MDA-MB-453), while the others lineages presented unmethylated alleles. The promoter region of isoform ESR1B was unmethylated in the cell lines BT549, SKBR3 and T47D; partial methylation were observed in the cell lines MDA-MB- 231, MCF-7 and ZR-75-30, while the others cell lines presented complete methylation. All lineages showed complete or partial methylation of the ESR2 gene. The methylation pattern of the promoter A of the PGR ...(Complete abstract click electronic access below)
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It is believed that epigenetic mechanisms such as DNA methylation are important for the tumorigenesis and maintenance of the altered state of tumor cells. DNA methylation occurs by the addition of a methyl group to carbon 5 of cytosine, catalyzed by the enzyme DNA methyl-transferase, which can change the expression of a gene, including the tumor suppressor genes. In human squamous cell carcinoma, several features have shown the etiological role of genes in tumor development. Among them, FOXE1 gene (forkhead box E1 - thyroid transcription factor) is presented with an important role in susceptibility to disease. Similarly the FOXE1 methylation pattern could alter the expression of this gene in dogs and predisposed to tumor on. Therefore, this study aims to investigate in dogs, the validity of the strategy employed in humans to analyze the FOXE1 methylation status. DNA extraction from fresh frozen tumoral samples was performed by Wizard Genomic® DNA Purification Kit. The methylation status was determined by MSP-PCR (methylation-specific polymerase chain reaction), using 2.0 ng of DNA treated with sodium bisulphate. One hundred micrograms of bisulphite-modified DNA was amplified using primers specific for either methylated or unmethylated DNA (primers sequences are available at http://pathology2.jhu.edu/pancreas/primer.pdf). The analysis of fragments was loaded on to 7% polyacrylamide gels and silver nitrate staining. In this stage of technical approach, 60% were FOXE1 hypermethylated. In conclusion, it was observed that the standard technique for assessing the methylation pattern of gene FOXE1 in humans can be used for the same evaluation in dogs. The correlation of these molecular data with clinical and histopathological parameters may have diagnostic and prognostic value and still be used as a tumor marker for therapeutic decision and surgical approach
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The NbCl5 being a strong electrophile, is a potential candidate to act as a Lewis acid, and therefore it mediates various organic reactions. For this reason, it has received continuous attention by Brazilian researchers, especially in recent decades, since Brazil holds the largest reserves of niobium, besides being the largest producer of this element. The Michael addition reaction is one of the most widely used for forming carbon-carbon bonds and takes place by the addition of nucleophiles to activated olefins. Although this type of reaction is usually catalyzed by base, there are reports in the literature on the use of various Lewis acids in this type of reaction. The synthesis of enamines based acetilenodicarboxilates and amines, aromatic or alkyl, by Michael addition reaction is quite interesting, since these are valuable synthetic intermediates for the synthesis of heterocyclic and they are used in multicomponent reactions. The derivatives of anilino-fumarate also have a great potential for medical application. In this study we investigated the use of niobium pentachloride as Lewis acid to catalyze the Michael additions between the derivatives of aniline and acetilenodicarboxilates the synthesis of enamines
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Ciências Biológicas (Genética) - IBB
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Multicomponent Reactions are defined as reactions between three or more reagents in a single reaction step in the same reaction vial, forming a product that includes the majority of atoms and structural characteristics of the reagents. Thus these reactions save time and energy. One of the ways to improve the yield and reaction time of a multicomponent reaction is to use different catalysts, an example of catalyst that shows great potential and has been studied in recent years is the molecular iodine is known to be a Lewis acid with high catalytic power. The functionalized piperidines, also known as tetrahydropyridines, are alkaloids that have pharmacological potential, this is due to the piperidine ring present in many natural product structures with muscarinic activity, nicotine, analgesic, antipsychotic, anti-proliferative, among others. In this paper we describe studies about on the application of molecular iodine (I2) in the multicomponent reaction between aniline derivatives, benzaldehyde and β-ketoester (methyl acetoacetate) for the synthesis of functionalized piperidines and the synthesis of a corresponding piperidone by acid hydrolysis. Data analysis allowed us to demonstrate the efficacy of molecular iodine in the synthesis of functionalized piperidines, obtaining results with yields 44-87% and short reaction time of 8 to 24 hours, and the efficacy of acid hydrolysis of enamine in the structure of the tetrahydropyridine derivative in a yield of 81%
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Pós-graduação em Ciência dos Materiais - FEIS
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Though benign, giant cell tumor of bone (GCTB) can become aggressive and can exhibit a high mitotic rate, necrosis and rarely vascular invasion and metastasis. GCTB has unique histologic characteristics, a high rate of multinucleated cells, a variable and unpredictable growth potential and uncertain biological behavior. In this study, we sought to identify genes differentially expressed in GCTB, thus building a molecular profile of this tumor. We performed quantitative real-time polymerase chain reaction (qPCR), immunohistochemistry and analyses of methylation to identify genes that are putatively associated with GCTB. The expression of the ADAM23 and CDKN2A genes was decreased in GCTB samples compared to normal bone tissue, measured by qPCR. Additionally, a high hypermethylation frequency of the promoter regions of ADAM23 and CDKN2A in GCTB was observed. The expression of the MAP2K3, MMP14, TIMP2 and VIM genes was significantly higher in GCTB than in normal bone tissue, a fact that was confirmed by qPCR and immunohistochemistry. The set of genes identified here furthers our understanding of the molecular basis of GCTB.