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1
Huguet, Emmanuel L. "Wnt genes in human breast biology." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297228.
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Torres, Monica Alexandra. "WNT signaling pathways in Xenopus laevis /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/6293.
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Nambiar, Roopa. "Zebrafish hdac1 reciprocally regulates the canonical and non-canonical Wnt pathways." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1150313622.
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Lako, Majlinda. "Identifying and characterising novel human WNT genes." Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242351.
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Leal, Letícia Ferro. "Via Wnt/?-catenina em tumores adrenocorticais pediátricos." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/17/17144/tde-06012016-181445/.
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Introdução: Em crianças das regiões Sul e Sudeste do Brasil há uma incidência elevada de tumores adrenocorticais (TAC). Anormalidades da ?-catenina tem sido encontradas em TAC em adultos e sugerem a ativação da via Wnt/ -catenina nestes tumores. No entanto, não há estudos avaliando o papel desta via em casuísticas de TAC pediátricos. Objetivos: Avaliar o papel da via Wnt/catenina e mutações do gene CTNNB1 na tumorigênese adrenocortical pediátrica. Indivíduos, Material e Métodos: Foram avaliados 62 pacientes pediátricos com TAC oriundos de dois centros de referência. Controles: córtex adrenal de indivíduos jovens com morte acidental. Avaliou-se a presença de mutação nos genes TP53 e CTNNB1. A expressão de genes da via Wnt (CTNNB1, o ligante WNT4, os inibidores SFRP1, DKK3 e AXIN1, o fator de transcrição TCF7 e os genes-alvo MYC e WISP2) foi avaliada por qPCR, utilizando-se o método de 2-Ct. Adicionalmente, a expressão de proteínas da via Wnt/-catenina e P53 foi avaliada por imunoistoquímica. Avaliou-se a relação entre possíveis anormalidades moleculares com o fenótipo clínico e o desfecho. Resultados: A sobrevida geral foi maior em pacientes menores que 5 anos de idade (p<0.0001) e em pacientes com estágios tumorais menos avançados (p<0.0001). A mutação P53 p.R337H foi encontrada em 87% dos pacientes e não se associou com características clinicopatológicas ou desfecho. Mutações do gene CTNNB1 foram encontradas em 4/62 (6%) TAC, todos carreadores da mutação P53 p.R337H. Houve associação entre óbito e presença de mutações do gene CTNNB1 (p=0,02). Acúmulo difuso da -catenina foi observado em 71% dos TAC, a maioria sem mutações do CTNNB1. Comparados a adrenais normais, os TAC apresentaram aumento da expressão do RNAm de CTNNB1 (p=0.008) e diminuição da expressão de genes inibidores da via Wnt: DKK3 (p<0.0001), SFRP1 (p=0.05) e AXIN1 (p=0.04). Com relação aos genes-alvo da via Wnt/-catenina, TAC apresentaram expressão aumentada de WISP2 e baixa expressão de MYC. Maior sobrevida geral foi associada à expressão baixa de SFRP1 (p=0.01), WNT4 (p=0.004) e TCF7 (p<0.01). Conclusões: Em TAC pediátricos, mutações somáticas ativadoras do gene CTNNB1 são pouco freqüentes e parecem estar associadas à maior ocorrência de óbito. Mesmo na ausência de mutações do gene CTNNB1, estes tumores apresentaram acúmulo de -catenina e do gene-alvo WISP2 e expressão reduzida de inibidores da via Wnt (DKK3, SFRP1 e AXIN1). Estes dados demonstram evidências de anormalidades na via Wnt/-catenina em TAC pediátricos, mesmo na ausência de mutações do gene CTNNB1. É provável que outros eventos genéticos afetando a via Wnt/-catenina estejam envolvidos na tumorigênese adrenocortical pediátricaContext: CTNNB1 mutations and activation of Wnt/-catenin pathway are frequent in adult adrenocortical tumors (ACTs) but data on childhood ACTs are lacking. Objective: To investigate Wnt/-catenin pathway abnormalities and CTNNB1 mutations in childhood ACTs. Patients and Methods: Clinicopathological findings and outcome of 62 childhood ACTs patients were analyzed regarding to CTNNB1/ -catenin mutations and to the expression of Wnt-related genes (CTNNB1, a Wnt ligand: WNT4, Wnt inhibitors: SFRP1, DKK3 and AXIN1, a transcription factor: TCF7, and target genes: MYC and WISP2) by qPCR and immunohistochemistry. Results: Overall survival (OS) was higher in patients younger than 5 years (p<0.0001) and associated with less advanced tumoral stage (p<0.0001). The p.R337H P53 mutation, found in 87% of the patients, was not associated with clinicopathological findings or outcome. CTNNB1 activating mutations were found in only 4/62 ACTs (6%), all of them harboring TP53 mutation. There was association between the presence of CTNNB1 mutation and death (p=0.02). Diffuse -catenin accumulation was found in 71% of ACTs, most of them without CTNNB1 mutation. CTNNB1 mutated ACTs presented weak/moderate -catenin accumulation. Compared to normal adrenals, ACTs presented increased expression of CTNNB1 (p=0.008) and underexpression of Wnt inhibitor genes: DKK3 (p<0.0001), SFRP1 (p=0.05) and AXIN1 (p=0.04). With regards to Wnt/-catenin target genes, ACTs presented lower expression of MYC but increased expression of WISP2. Higher overall survival was associated with underexpression of SFRP1 (p=0.01), WNT4 (p=0.004) and TCF7 (p<0.01). Conclusions: In childhood ACTs, CTNNB1 mutations are rare and appear to be associated with poor prognosis. Regardless of CTNNB1 mutations, these tumors presented reduced expression of Wnt inhibitor genes (DKK3, SFRP1 and AXIN1) and increased expression of CTNNB1 and a target gene, WISP2. Thus, besides CTNNB1 mutations, additional genetic events affecting the Wnt/-catenin pathway may be involved in childhood adrenocortical tumorigenesis.
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Chow, Hei-man, and 周熙文. "Hormonal, chemical, and transcriptional regulations of Wnt/{221}-catenin signaling in mammary carcinogensis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B4589100X.
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Ng, Chun-laam, and 吳圳嵐. "Wnt inhibitory factor 1 (Wif-1) coordinates Shh and Wnt signaling activities in urorectal development." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48329629.
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In vertebrates, the urogenital sinus and the hindgut are connected at a hollow region called cloaca. A midline mesenchymal structure known as urorectal septum (urs) descends from the ventral body wall to separate the urogenital sinus from the hindgut before the formation of an anal opening. Subsequent cloaca membrane regression at the ventral midline of the genital tubercle (GT) is crucial for the formation of an anal opening. These two events are important during cloaca septation in urorectal development.
Mice with defective Shh or Wnt signaling displayed similar urorectal defects such as GT agenesis, un-partitioned cloaca (persistent cloaca) and proximal urethral opening that are attributable to increased cell apoptosis. Furthermore, Shh and Wnt signal transduction coordinate with each other and regulate cell survival of the developing urorectum. However, the molecular mechanisms by which these two signaling pathways coordinate in urorectal development remain unclear.
We previously identified Wnt inhibitory factor1 (Wif1) from Affymetrix array analysis for genes/pathways that is implicated in urorectal development. Wif1 is a secreted protein that binds directly to Wnt ligands preventing Wnts from binding to receptors. This leads to -catenin degradation and thereby inhibits their activities. It is known that Wif1 binds to Wnt3a and Wnt5a with high affinity and deletion of Wnt3a, Wnt5a and -catenin in mice caused GT agenesis, persistent cloaca and proximal hypospadias. Using ETU-induced anorectal malformations model, I found out that Wif1 is ectopically expressed in the un-tubularized and un-septated urorectum. Wif1 is mainly expressed at the fusing endoderm that associates with programmed cell death during cloaca septation. Exogenous addition of Wif1 protein in urorectum culture also caused cloaca membrane disintegration, and proximal urethral opening that may be due to aberrant apoptosis.
Shh and Wif1 are differentially expressed at the cloaca endoderm. In normal mice, Shh is highly expressed at the cloaca endoderm except those Wif1-expressing endodermal cells. Blockage of Shh pathway by cyclopamine in urorectum culture induced ectopic expression of Wif1, concomitant with genital tubercle hypoplasia and un-septated cloaca. More importantly, deletion of Shh in mice hastened Wif1 expression at the cloaca membrane endoderm and elicited increased cell death in the
Wif1 expressing endoderm. Wif1-/- embryos display urorectal defects including delayed genital outgrowth and proximal hypospadias. Therefore, disruption of spatiotemporal expression of Wif1 could lead to defective Wnt signaling and contributes to abnormal urorectal development in Shh-/- mutant.
Current study revealed that Wif1 is involved in urorectal development and is implicated in urorectal defects. It may function as a pro-apoptotic factor to regulate endodermal cell death which is essential for the septation process. Its specific expression is restricted at the midline cloaca endoderm by Shh signaling to inhibit local Wnt--catenin activities during cloaca septation. I proposed novel hypothetical models to explain (1) the significance of the tempo-spatial expression of Wif1; (2) the significance of cell death; and (3) the molecular mechanism that Shh signaling regulates Wnt signaling activities through Wif1 in urorectal development.published_or_final_version
Surgery
Doctoral
Doctor of Philosophy
8
Railo, A. (Antti). "Wnt-11 signalling, its role in cardiogenesis and identification of Wnt/β-catenin pathway target genes." Doctoral thesis, University of Oulu, 2010. http://urn.fi/urn:isbn:9789514261534.
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Abstract
Wnt genes encode secreted signalling molecules that control embryonic development including organogenesis, while dysregulated Wnt signalling is connected to many diseases such as cancer. Specifically, Wnts control a number of cellular processes such as proliferation, adhesion, differentiation and aging. Many Wnt proteins activate the canonical β-catenin signalling pathway that regulates transcription of a still poorly characterized set of target genes. Wnts also transduce their signaling in cells via β-catenin-independent “non-canonical” pathways, which are not well understood. In this study, Wnt-11 signalling mechanisms in a mammalian model cell line and roles of Wnt-11 in heart development were analyzed in detail. In addition the aim was to identify new Wnt target genes by direct chromatin immunoprecipitation and Affymetrix GeneChip assays in the model cells exposed to Wnt-3a.
Our studies reveal that Wnt-11 signalling coordinates the activity of key cell signalling pathways, namely the canonical Wnt/β-catenin, the JNK/AP-1, the NF-κB and PI3K/Akt pathways in the CHO cells. Analysis of the Wnt-11-deficient embryos revealed a crucial role in heart organogenesis. Wnt-11 signalling coordinates cell interactions during assembly of the myocardial wall and Wnt-11 localizes the expression of N-cadherin and β-catenin to specific cellular domains in the embryonic ventricular cardiomyocytes. Collectively these studies reveal that the mammalian Wnt-11 behaves as a non-canonical Wnt and that it is a critical factor in the coordination of heart development. Specifically, it controls components of the cell adhesion machinery. Analysis of the Wnt target genes revealed a highly context-dependent profile in the Wnt-regulated genes. Several new putative target genes were discovered. Out of the candidate Wnt target genes, Disabled-2 was identified as a potential new direct target for Wnt signalling.
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Sobreira, Debora Rodrigues 1981. "Identificação de uma nova variante do gene Dapper1 gerada por splicing alternativo durante o desenvolvimento de vertebrados e sua analise numa abordagem evolutiva." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317676.
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Orientadores: Lucia Elvira Alvares, Jose Xavier NetoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-13T10:17:43Z (GMT). No. of bitstreams: 1 Sobreira_DeboraRodrigues_M.pdf: 2481929 bytes, checksum: 2cb1105ccc78322b5f11f4528108d2fc (MD5) Previous issue date: 2009
Resumo: Splicing Alternativo é um mecanismo importante para expandir a diversidade protéica em eucariotos. Este processo permite a produção de diferentes mRNAs a partir de uma mesma molécula de pré-RNA e é freqüentemente utilizado pelos genes envolvidos no desenvolvimento embrionário. O gene Oapper1 (Opr1) é um importante modulador da via de sinalização Wnt, atuando em diversos processos como especificação do tecido neural, morfogênese cefálica e desenvolvimento do coração e olho. Entre seus parceiros estão as '1lOléculas Dishevelled, o fator de transcrição TCF-3 (ambas as moléculas envolvidas na sinalização Wnt) e Dbf-4 (regulador do ciclo celular). Considerando que Dpr1 possui uma estrutura modular e interage com diferentes parceiros moleculares através de diferentes domínios estruturais, esta molécula poderia utilizar a maquinaria de Splicing Alternativo para combinar diferentes domínios e conseqüentemente ampliar suas funções biológicas. Neste estudo, descrevemos uma nova Variante do gene Opr1, identificada inicialmente no transcriptoma de camundongo utilizando ferramentas de Bioinformática. Esta nova Variante é maior em 111 pb em relação à codificada pela seqüência referência de RNAm para Dpr1 RefSeq, as quais são denominadas, respectivamente, como Variante A e Variante B. Estes transcritos variantes são gerados por dois sítios aceptores de Splicing distintos presentes no início do exon 4. O segmento exclusivo da Variante A codifica 37 aminoácidos localizados na região onde Opr1 se associa ao fator transcricional TCF-3. Uma análise comparativa do lócus de Opr1 entre diversos vertebrados (peixe, anfíbio, galinha, camundongo e humano) revelou que ambos os sítios aceptores de Splicing são conservados nos tetrápodas, enquanto que em peixe apenas um sítio é encontrado. Ensaios de RT-PCR confirmaram nossos resultados obtidos em Bioinformática. Além disso, demonstramos que ambas as Variantes são co-expressas ao longo do desenvolvimento de galinha, sugerindo que a concentração relativa dessas moléculas pode ser importante para a sua função. Finalmente, análises de pressão seletiva foram realizadas para a molécula de Dpr1. Apesar de não se confirmar a presença de seleção positiva ao longo da proteína Dpr1, o exon 4 parece estar sob pressão seletiva mais relaxada quando comparado aos outros exons. Nossos resultados são consistentes com a hipótese de que o mecanismo de Splicing Alternativo atua acelerando a evolução, reduzindo a seleção negativa.
Abstract: Alternative splicing is an important mechanism to expand protein diversity in eukaryotes. This process allows the production of different mRNAs from a single coding sequence and is frequentfy used by genes involved in development. Oapper 1 (Opr1) is an important rnodulator of Wnt signalling, working in several developmental processes, such as neural tissue specification, head morphogenesis, heart and eye development. While its interaction with Oishevelled is known to modulate Wnt signalling both in vivo and in vitre, the interaction wrth other molecules is required to mediate its multiple biological functions. Considering that Dpr1 has a modular structure that mediates its interaction with different partners through different structural domains, this molecule could greatly benefit from alternative splicing in order to combine different domains and consequently amplify its biological functions. In the present study we describe a new Opr1 isoform that was initially identified in the mouse transcriptome using bioinformatic tools. This isoform is 111 pb longer than the one encoded by the RefSeq mRNA for Opr1, here named O and E isoforms, respectively. The variant transcripts are generated through two distinct acceptor splice sites in exon 4. The segment exclusive of the O isoform is in frame and encodes 37 residues located in a variable region of Oprl exon 4, known to be necessary for the interaction with the transcriptional factor Tcf3. comparative analysis of the Opr1 locus among fish, frog, chicken, mouse and human revealed that in tetrapods two acceptor splice sites are conserved in the beginning of the exon 4, while in fish a single acceptor splice site is found. RT-PCR using species-specific primers confirmed the expression of the O and E isoforms in tetrapods while in fish only the O isoform was detected. In addition, we showed that the Opr1 isoforms are coexpressed throughout chicken development, suggesting that the relative concentration of these molecules may be important for their functionality. Finally, even though no evidence of positive selection was detected for the entire Dpr1 protein, exon 4 seems to be under more relaxed selective pressure than the other exons. These results are consistent with the notion that alternative splicing can act as a mechanism for opening accelerated paths of evolution by reducing negative selection pressure.
Mestrado
Histologia
Mestre em Biologia Celular e Estrutural
10
Ho, Sze-hang, and 何思恆. "Differential expression of Wnt inhibitors Dickkopf-1 (Dkk-1) and Wnt inhibitory factor-1 (Wif1) in the regulation of urorectal development." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/207999.
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In mammals, the external genitalia, urinary tract and anorectal tract are developed from a common embryonic primordium, the urorectum. Cloaca is the hollow space inside the urorectum that connects the hindgut and the urogenital sinus. During the urorectal development, the external genitalia is formed from the outgrowth of genital tubercle (GT) protruding from the urorectum, while the future urinary tract and anorectal tract are formed by the partition of cloaca during cloacal septation. GT outgrowth and cloacal septation are important developmental events for the formation of genitourinary and anorectal system. In human, dysregulation of these developmental events results in congenital anorectal malformations (ARM).
Wnt signaling is one of the key signaling pathways that regulates urorectal development. The activity of Wnt signaling is initiated by the binding of Wnt ligands to cell surface receptors, which can be antagonized by secretory Wnt inhibitors. Dickkopf1 (Dkk1) and Wnt inhibitory factor 1 (Wif1) are secretory Wnt inhibitors implicated in urorectal development. However, the functions of other secretory Wnt inhibitors during urorectal developments remain to be elucidated.
In this study, expression analyses showed that Dkk1, Dickkopf2 (Dkk2), Dickkopf4 (Dkk4), Secreted Frizzled-related Protein 1 (Sfrp1) and Wif1 were expressed in the developing urorectum. The dynamic, overlapping and restricted expression patterns of these Wnt inhibitors were closely associated with the GT outgrowth and the cloacal septation events, implying that these Wnt inhibitors functioned in a coordinated manner in defining the field of Wnt signaling activities in the developing urorectum.
Wif1 knockout mice (〖Wif1〗^(-/-)) was used as the model to investigate the functions of and the interplay between secretory Wnt inhibitors in urorectal development. GT outgrowth and cloacal septation defects were observed in 〖Wif1〗^(-/-) embryos. Most of the 〖Wif1〗^(-/-) embryos displayed varying degrees of GT outgrowth defects, while septation defects were only occasionally observed. This suggested that GT outgrowth and cloacal septation were regulated by Wif1 via different regulatory mechanisms.
In the urorectum of 〖Wif1〗^(-/-) embryos, Dkk1 was significantly upregulated in the peri-cloacal mesenchyme. Further expression analysis suggested that Dkk1 was sufficient to rescue cloacal septation defects but not GT outgrowth defects in 〖Wif1〗^(-/-)embryos. In the 〖Wif1〗^(-/-) embryos with severe GT outgrowth defects, the Fgf8-expressing distal urethral epithelium, the signaling center in the urorectum, was absent, suggesting that the GT outgrowth defects could be contributed by the loss of dUE-expressing signals such as Fgf8.
This study demonstrated the importance of secretory Wnt inhibitors in the GT outgrowth and cloacal septation and suggested that secretory Wnt inhibitors played partially overlapping roles in urorectal development. A rescue mechanism for cloacal septation performed by Dkk1 upon Wif1 deletion was proposed. Such auto-regulatory mechanism within the Wnt signaling pathway indicated that Wnt inhibitors play essential regulatory roles in the urorectal development and a balanced Wnt signaling activity modulated by Wnt inhibitors is crucial to the development of urorectum.published_or_final_version
Surgery
Master
Master of Philosophy
11
Hogvall, Mattias. "Analysis of Wnt ligands and Fz receptors in Ecdysozoa : Investigating the evolution of segmentation." Licentiate thesis, Uppsala universitet, Paleobiologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-266019.
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Yang, Xuesong, and 楊雪松. "Identification of epigenetic biomarkers for diagnosis of nasopharyngeal carcinoma and determination of WIF1 functional relevance." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/209492.
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Nasopharyngeal carcinoma (NPC) is closely associated with Epstein-Barr Virus (EBV).Early diagnosis of NPC will improve the overall survival. However, traditional EBV markers do not perform well in high-risk individuals or for early detection of NPC. Aberrant promoter hypermethylation of tumor suppressor genes (TSGs) is an important epigenetic change in early tumorigenesis. This study identified a promising panel of methylation markers for early detection of NPC and assessed the clinical usefulness of these markers using nasopharyngeal (NP) brushing and blood specimens.
Methylation-sensitive high resolution melting (MS-HRM) assays were carried out to assess the methylation status of a selected panel of four TSGs (RASSF1A, WIF1, DAPK1, RAR2)in biopsies, NP brushings and cell-free plasma from NPC patients. NP brushing and blood samples from high-risk and cancer-free groups were used as controls.
The DNA methylation panel showed higher sensitivity and specificity than the EBV DNA markerincell-free plasma for early stage (Iand II) NPC (sensitivity: 64.6% vs. 51.2% and specificity: 96.0% vs. 88.0%, respectively). In combination with plasma EBV DNA, testing for DNA methylation in plasma and NP brushings using the four-gene MS-HRM test significantly increased the detection rate for all stages of NPC(94.1% for stages I-II, 98.4% for stages III-IV) as well as recurrence(93.5%).
Aberrant activation of the Wnt signaling pathway is a common mechanism for cell transformation and tumor development in a variety of human cancers. A high frequency of promoter hypermethylation of WIF1was observed in NPC cell lines (100%), primary tumor biopsies(89.7%), NP brushings (80.2%), and cell-free plasma (51.8%),with no significant correlation with NPC stage. Simultaneously, expression of WIF1 was completely silenced in NPC cell lines (HONE1, HK1, HNE1, SUNE1, CNE1, CNE2, and C666),but not in immortalized NP epithelial cells (NP460 and NP69). These together suggested an important role of WIF1 in NPC development.
In vitro and in vivo functional assays revealed a tumor suppressive role of WIF1in NPC. Restoration of WIF1expression in NPC cells significantly suppressed anchorage-independent growth, in vivo tumorigenicity, invasion, migration, and angiogenesis of NPC cells. A number of important angiogenesis-related genes were down-regulated by WIF1expression, including IL6,IL8,VEGF165,VEGFA, PDGFB, and MCP1. There is inhibition of the Wnt/β-catenin signaling pathway, manifested as decreased β-catenin expression and TCF/LEF Wnt promoter activity. These data indicated the important regulatory role of Wnt signaling pathway in NPC tumorigenicity, invasion, migration, and angiogenesis, by interacting with the complex signaling network in NPC cells.
To conclude, the MS-HRM assay on the selected gene panel in combination with the EBV DNA test, increases the sensitivity for NPC detection at an early stage and detection of recurrence and has great potential to become a non-invasive test for early diagnosis and disease monitoring after treatment. Collectively, results from this study reveal that WIF1is not only a sensitive biomarker, but also a tumor suppressor gene in NPC. Understanding the molecular regulatory role ofWIF1in NPC will facilitate the diagnosis of NPC, and development of novel NPC therapeutic strategy.published_or_final_version
Clinical Oncology
Doctoral
Doctor of Philosophy
13
Kenny, Paraic A. "Identification of Wnt-1l0-catenin responsive genes in mouse mammary epithelial cells." Thesis, Institute of Cancer Research (University Of London), 2002. http://publications.icr.ac.uk/9712/.
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The Wnt/β-catenin signal transduction pathway plays a central role in metazoan development, controlling such diverse processes as cell growth, proliferation and organogenesis. Wnt-1 was initially identified as a mammary oncogene. Mutations in other components of this signal transduction pathway - APC, β-catenin and Axin - have been implicated in the initiation and progression of an increasing number of human malignancies. Aberrant activation of this pathway leads to the inappropriate expression of target genes such as c-MYC and CYCLIN D1. Elucidation of additional target genes of this pathway will shed further light upon the mechanisms underlying the malignant phenotype. As an in vitro model of Wnt/β-catenin signalling in the mouse mammary gland, mammary epithelial cell lines were generated in which this pathway could be activated in a tetracycline-dependent manner. The transcriptional consequences of aberrant Wnt/β-catenin signalling were then investigated using cDNA microarrays. Using this approach, 70 genes have been identified as being potential transcriptionally upregulated targets of the pathway and a similar number have been shown to be repressed. Similar experiments were performed in a colorectal cancer cell line lacking functional APC. An analysis of a representative sample of these differentially expressed genes is presented here. The use of human tumour tissue microarrays containing 300 tumour samples from a variety of tissues was validated as an approach to test the relevance of candidate genes.
14
Kenny, Paraic Anthony. "Identification of WNT-1/Beta-catenin responsive genes in mouse mammary cells." Thesis, Institute of Cancer Research (University Of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269621.
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Kwan, Hoi-tung, and 關愷彤. "AMPK activators inhibit cervical cancer cell growth through reduction of Dvl3 in Wnt/{221}-catenin signaling." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46936087.
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Tsui, Yu-man, and 徐宇文. "Study of the roles of dishevelled-3 in stemness and cell migration in hepatocellular carcinoma." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196460.
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Hepatocellular carcinoma (HCC) is a common malignancy worldwide and particularly common in China and Southeast Asia. It ranks the 2nd and 4th most common fatal cancer in males and females, respectively, in Hong Kong. Current treatments are not always effective, as recurrence and metastasis in HCC are difficult to tackle and the underlying mechanisms not fully understood. Aberration of Wnt signaling has been implicated in HCC; in this study, we investigated the underlying mechanisms of how aberrant Wnt signaling promoted HCC development. With Taqman Low Density Array (LDA) analysis on 38 pairs of HCC and the corresponding non-tumorous livers for 59 Wnt signaling related-genes, we found significant overexpression of the Wnt signaling intermediate, Dishevelled (Dvl)-3, in HCC (p = 0.014). This observation in LDA was confirmed in 36 additional HCC cases. Among a total of 74 cases studied, 28.38% showed more than 3-fold overexpression in the tumors as compared with the corresponding non-tumorous livers. Dvl3 overexpression positively correlated with the presence of venous invasion. We also observed significant correlation of Dvl3 expression with accumulation of β-catenin, a downstream effecter of Wnt/β-catenin signaling (p=0.028).
We further characterized the functional roles of Dvl3 in contributing to the stem cell-like and metastatic properties of HCC. We found that Dvl3 knockdown in HCC cells suppressed cell proliferation, sphere formation, tumorigenicity in immunodeficient mice, chemo-resistance, and expression of stemness genes. We then examined whether Wnt/β-catenin was effectively modulated by Dvl3 and found that Dvl3 overexpression and knockdown, respectively, promoted and reduced the TOP/FOP luciferase reporter activity in HCC cells. This was accompanied by the expression of β-catenin target genes, EpCAM and LGR5, both of which are associated with HCC stemness. Furthermore, rescue with wild-type or constitutively active β-catenin partially restored the in vivo tumorigenicity suppressed by Dvl3 knockdown, indicating a partial role of β-catenin in mediating the effects of Dvl3 on HCC stemness.
In addition, since cell migration is a critical determinant in metastasis, we assessed the HCC cell migratory ability in vitro using transwell migration assays and observed suppression of the cell migration ability upon Dvl3 knockdown. Also, the in vivo orthotopic model confirmed a role of Dvl3 in promoting metastasis, as stable Dvl3 knockdown in HCC cells resulted in a reduction in lung metastasis. Interestingly, the effect of Dvl3 on cell migration was independent of β-catenin, as knockdown of β-catenin had no effect on HCC cell migration in vitro. It was also not related to the phosphorylation of MYPT in Rho-ROCK signaling, which itself was previously implicated in HCC cells metastasis and reported as a downstream signaling of Dvl in development.
In summary, our study has identified roles of Dvl3 in HCC stemness properties and cell migration and this may provide functional implication of Dvl3 overexpression, which significantly correlated with venous invasion in human HCCs. Also, β-catenin is partly responsible for the role of Dvl3 in HCC stemness but independent of that in cell migration.
Functional characterization of Dvl3 in HCC may help future development of therapy targeting Dvl3 of Wnt signaling pathways.published_or_final_version
Pathology
Doctoral
Doctor of Philosophy
17
Schubert, Michael. "Wnt family genes in the cephalochordate amphioxus : structure, phylogenetic analysis, and developmental expression /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2001. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035434.
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Leal, Marcelo Larciprete. "Genes da via WNT são diferencialmente modulados por protocolos de treinamento de força." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/42/42134/tde-02022010-115900/.
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A proposta deste estudo foi avaliar o efeito de 8 semanas de treinamento de força ou potência sobre a expressão de genes pertencentes a via de sinalização canônica da WNT, assim como a expressão protéica de b-catenina. Vinte e cinco indivíduos (27,4±4,6 anos) foram distribuídos randomicamente nos grupos: treinamento de força (TF) (n=10), treinamento de potência (TP) (n=10), e controle (C) (n=5). Os grupos TF e TP realizaram o exercício agachamento durante 8 semanas, 3 vezes por semana. Biópsias do músculo vasto lateral foram retiradas antes e após o período de treinamento. Alguns genes foram modulados positivamente no grupo TF (WNT1:6.4 vezesP<0.0001; SFRP1:3.3 vezesP<0.0001 e LEF1:7.3 vezesP<0.0001) e também no grupo TP (WNT1:24.9 vezesP<0.0001; SFRP1:2.7 vezesP<0.0001; LEF1:34.1 vezesP<0.0001 e Cyclina D1:7.7 vezesP<0.001). O conteúdo protéico total de -catenina aumentou somente no grupo TP (p<0,05). Nossos dados indicam que o treinamento de potência desencadeia respostas de maior magnitude sobre a via WNT quando comparado ao treinamento de força máxima.The purpose of the present study was to evaluate the effects of 8 weeks of strength and power training on the expression of genes related to the canonical WNT pathway and b-catenin protein levels. Twenty five subjects (27.4±4.6 yrs) were randomly assigned to three groups: strength training (ST) (n=10), power training (PT) (n=10), and control (C) (n=5). The ST and the PT groups performed squats, 3 times per week, for 8 weeks. Muscle biopsies from the vastus lateralis muscle were collected before and after the training period. Certain genes were up-regulated in the ST group (WNT1:6.4 foldP<0.0001; SFRP1:3.3 fold-P<0.0001 and LEF1:7.3 foldP<0.0001) and also in the PT group (WNT1:24.9 foldP<0.0001; SFRP1:2.7 foldP<0.0001; LEF1:34.1 foldP<0.0001 and Cyclin D1:7.7 foldP<0.001). Finally, the total protein content of -catenin increased only in the PT group (P<0.05). Our data indicate that PT triggers greater responses on the WNT pathway as compared to ST regimens.
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Yardy, George William. "Mutations in genes of the Wnt signalling pathway and PML in prostate cancer." Thesis, St George's, University of London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442060.
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Campos, Simone Becho de. "Estudo de genes da Via Wnt e sua associacao com o Transtorno Afetivo Bipolar." Universidade Federal de Minas Gerais, 2013. http://hdl.handle.net/1843/BUBD-9FYGVM.
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Bipolar Disorder (BD) is a severe and chronic psychiatric illness with progressive increase in the severity of episodes. The prognosis for patients with BD is poor, with high rates of relapse in residual symptoms, cognitive impairment and decreased quality of life. A growing body of research supports the assumption that BD arises from abnormalities in neuronal plasticity. Several lines of evidence suggests that the Wnt family is involved in this pathway since it is related to key developmental processes such as cell growth, migration and cell differentiation. Therefore, the aim of our study was to evaluate whether genes of the Wnt pathway are associated to BD and its comorbidities. Our sample consisted of 546 individuals: 306 patients with BD and 240 healthy controls. We used the genes WNT2B, WNT3A, WNT5A, WNT7A, APC1 and FZD3. We found no correlation between the studied tagSNPs and BD. However, we found a positive association between ACP1 tagSNP, rs7419262, and violent suicide attempt, and between the WNT2B tagSNPs, rs3790606 and rs351372, and generalized anxiety disorder as a comorbidity in patients with BD. We conclude that the Wnt pathway may be associated with susceptibility to BD and suicide.O Transtorno Afetivo Bipolar (TAB) e um transtorno psiquiatrico grave, cronico e com progressivo aumento da gravidade dos episodios. O prognostico para os pacientes com TAB e pobre, com altas taxas de recaida, de sintomas residuais, disfuncoes cognitivas e de diminuicao da qualidade de vida. Um crescente corpo de estudos suporta a hipotese de que o TAB surge de anormalidades em cascatas de plasticidade celular, levando a processamento deficiente de informacao nas sinapses e circuitos de mediacao de funcoes afetivas e cognitivas. Varias linhas de evidencias sugerem que a via Wnt pode, tambem, estar envolvida na etiologia do TAB, pois esta via esta relacionada a processos de desenvolvimento essenciais tais como crescimento celular, migracao e diferenciacao celular. Por esse motivo, o objetivo do nosso estudo foi avaliar possiveis associacoes entre polimorfismos de alguns genes da via Wnt e a susceptibilidade ao TAB e comorbidades. Nossa amostra consistiu de 546 individuos, sendo 306 pacientes com TAB e 240 controles saudaveis. Utilizamos os genes WNT2B, WNT3A, WNT5A, WNT7A, APC1 e FZD3. Nas analises de associacao entre caso e controle, nao encontramos correlacao entre os tagSNPs estudados e o TAB. Encontramos associacao positiva entre o gene APC1, rs7419262, e tentativa de suicidio violenta e entre o gene WNT2B, rs3790606 e rs351372 e o transtorno de ansiedade generalizada como comorbidade em pacientes com TAB. Concluimos que a via Wnt pode estar associada a susceptibilidade ao TAB e suicidio.
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Wong, Yin-chi Betty. "Significance of LRP6 coreceptor upregulation in the aberrant activation of Wnt signaling in hepatocellular carcinoma." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41757865.
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Chan, Lai Sheung. "Therapeutic potential of a Wnt modulator ICG-001 on nasopharyngeal carcinoma." HKBU Institutional Repository, 2017. https://repository.hkbu.edu.hk/etd_oa/410.
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According to the cancer stem cells (CSCs) hypothesis, CSCs are responsible for the treatment failures. CSCs are a subset of cells possessing stemness properties within the heterogeneous tumor mass. Therapeutic intervention on Wnt signaling is of our great interest because an aberrant Wnt signaling is an important driver to maintain the potency of CSCs. In nasopharyngeal carcinoma (NPC), deregulated expression of the Wnt signaling components is frequently observed. ICG-001 is a selective Wnt modulator (CBP antagonist) that specifically interrupts the interaction between β-catenin and CBP, thereby encourages the interaction between β-catenin and p300 and the subsequent differentiation and reduction of the CSCs subset. For this reason, the present study aimed to evaluate the therapeutic potential of ICG-001 in NPC. Results showed that ICG-001 inhibited both the migration of the NPC cells and the formation of tumor spheres. In the first part of the mechanistic studies (Chapter 3), ICG-001 was found to restore the expression of miR-150 in NPC cells. MiR-150 was further found to directly reduce CD44 expression and inhibit NPC cell migration. In the second part of the mechanistic studies (Chapter 4), ICG-001 was found to reduce the expression of Evi1 in NPC cells. The effect was accompanied with the inhibition of both the NPC cells migration and the tumor spheres formation. Two molecular axes, namely miR-96/Evi1/miR-449a and survivin/Evi1/miR-449a, were found to be involved in the inhibition of the tumor cell migration and spheroids formation. The therapeutic potential of using this CBP antagonist (ICG-001) in NPC, namely the in vitro and in vivo efficacy of ICG-001 combined with cisplatin, was examined (Chapter 5). Concurrent treatment of ICG-001 and cisplatin exhibited a synergistic inhibition on the in vitro growth and the tumor sphere forming capacity of NPC cells as well as the growth of NPC xenografts. Taken together, results presented in this thesis suggested that ICG-001 (PRI-724 is the analog of ICG-001 currently used in clinical trials) has a therapeutic potential in NPC.
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Grünberg, John. "Studies on potential APC/β-catenin target genes in the Notch pathway." Thesis, Linköping University, Department of Physics, Chemistry and Biology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-18443.
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Both Notch and the Wnt pathways are key regulators in maintaining the homeostasis in the intestine. Defects on the key tumor suppressor adenomatous polyposis coli, APC a gene in the Wnt pathway is most frequently mutated in colorectal cancer. Previous studies have indicated that there is a crosstalk between these two pathways. We investigate if there is correlation by first using bioinformatics to find Lef1/Tcf sites in several of the Notch pathway gene promoters. Bioinformatically we found that a lot of the genes contained theses sites controlled by the APC's destruction target β-catenin. By using semi quantitative PCR and western blot we found that Hes 1, Hes 7, JAG 2, MAML 1, Notch 2, NUMB, NUMBL, RFNG and LFNG was downregulated in HT29 colon cancer cells carrying a vector containing wild type APC. All but JAG 2 contains at least one Lef1/Tcf site in their promoter region. The results were verified in HT29 cells transfected with siRNA against β-catenin. We also investigated what would happen to the Lef1/Tcf target gene program of the Wnt pathway, if the Notch pathway was inhibited with the gamma-secretase inhibitor DAPT. Results showed no downregulution of β-catenin or its target gene Cyclin D1.Taken together, these results demonstrate that the Wnt pathway can be placed upstream of the Notch pathway and regulates the latter through β-catenin and the Lef1/Tcf target gene program. However, preliminary results indicate that there is no regulation of APC/β-catenin by the Notch pathway.
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Theka, Ilda 1984. "Wnt/beta-catenin activity controls the stability of imprinted genes in mouse embryonic stem cells." Doctoral thesis, Universitat Pompeu Fabra, 2017. http://hdl.handle.net/10803/565761.
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Las células madre embrionarias (ESCs) derivan de la masa cellular interna de los blastocistos y son capaces de generar las tres capas germinales. Muchos factores controlan la pluripotencia incluyendo la ruta Wnt/β-catenina. La implicación de esta ruta en la renovación celular no ha sido aún esclarecida, mientras que su función es indispensable para la diferenciación de ESCs. En esta tesis investigamos como Wnt puede afectar la stabilidad epigenética de las ESCs. Interesantemente, observamos que la reducción de señal Wnt/β-catenina provoca desmetilación del ADN y perdida de represores de la cromatina en varias regiones de control de la impronta genética (ICR). Al contrario, el mantenimiento de Wnt/β-catenina no afectó el estado de los ICR. Además, mostramos que β-catenina puede interaccionar directamente con KAP1 y ZFP57, Finalmente, demostramos que una baja dosis de Wnt/β-catenina es necesaria durante los eventos tempranos de reprogramación cellular, pero la inhibición continua de Wnt perjudica este proceso.Mouse embryonic stem cells (ESCs) derive from the inner cell mass of the blastocyst and they are able to generate the three germ layers. Many factors control ESC pluripotency including Wnt/β-catenin signaling pathway. The implication of Wnt/β-catenin pathway in self-renewal remains still unclear, whereas its function is indispensable for ESC differentiation. In this study we investigate the effect of Wnt activity on ESC epigenetic stability. Indeed we observed that loss of Wnt/β-catenin signaling causes loss of DNA methylation and chromatin repressors recruitment, such as H3K9me3 and ZFP57, at several imprinted control region (ICR). On the contrary, sustained Wnt/β-catenin signaling protected the ICR status. Moreover, we showed that β-catenin could directly interact with KAP1 and ZFP57 proteins. Finally, we demonstrated that a low dosage of Wnt/β-catenin signaling is necessary during the early stages of somatic cell reprogramming process. However continuous inhibition of Wnt/β-catenin pathway is detrimental to this process.
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Sobreira, Debora Rodrigues 1981. "Estudos sobre os genes da família Dapper = origem, evolução e análise da expressão durante a ontogênese dos membros de galinha = Studies on the Dapper gene family : origin, evolution and expression analysis during chicken limb development." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317678.
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Orientadores: Lúcia Elvira Alvares, José Xavier NetoTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Os genes da família Dapper (Dpr) codificam proteínas adaptadoras capazes de ligar-se fisicamente a diferentes moléculas e modular as vias de sinalização Wnt e TGF-?. Diferentes análises funcionais revelaram que os Dpr atuam na especificação do eixo corporal e do tecido neural, nos movimentos morfogenéticos, no desenvolvimento do olho, na indução da cardiogênese, adipogênse e cicatrização. Diversos estudos foram realizados a fim de compreender o papel desempenhado pelos Dpr durante a embriogenêse dos vertebrados e na homeostase de tecidos adultos. Contudo, muitas questões ainda necessitam ser elucidadas. Este projeto de Doutorado teve como objetivo (1) descrever os sítios de expressão da família gênica Dpr durante a ontogênese dos membros de galinha, associando-a as vias de sinalização Wnt e TGF-? e (2) investigar a origem e a evolução desses genes durante a filogenia dos metazoários. Nossos resultados confirmaram que os genes Dpr são dinamicamente expressos durante o desenvolvimento dos membros de galinha, provavelmente, modulando os sinais Wnt e TGF-?. Os genes Dpr são encontrados no mesênquima indiferenciado dos membros em formação e em células progenitoras de condrócitos, pericôndrio e tendões. Esses resultados sugerem as moléculas Dpr como um novo grupo de marcadores do desenvolvimento dos membros em galinha. Já nossas análises filogenéticas revelaram que os Dprs surgiram durante a evolução dos organismos deuterostômios e um novo ortólogo dessa família de proteínas, denominado Dpr4, foi descrito. Acreditamos que o nosso trabalho irá fornecer bases para estudos moleculares com o intuito de estabelecer a função individual de cada membro da família Dpr, bem como auxiliar no entendimento sobre como estas proteínas podem interagir e cooperar entre si para modular diferentes vias de sinalização molecular em diferentes contextos celulares
Abstract: The Dapper (Dpr) genes form a small gene family of adaptor proteins important to several processes of vertebrates development, such as the specification of the body axis and neural tissue, morphogenetic movements, eye development, induction of cardiogenesis, adipogenesis and wound healing, by modulating the Wnt and TGF-? signaling pathways using specific conserved domains/motifs. Three Dpr genes have been identified in human and mouse, two in chicken, one in frog and two in zebrafish genome. Since the discovery of Dpr proteins, several assays have been performed in order to understand the role of this family during embryogenesis, although many questions still need to be elucidated. Thus, this PhD project aimed to (1) describe the possible role of Dpr genes during ontogeny of chicken regarding the regulation of Wnt and TGF-? signaling pathways and (2) investigate the origin and evolution of Dpr family over the course of metazoan evolution. Our results demonstrated that Dpr genes are involved in chicken limb development, probably, by modulating Wnt and TGF-? signals. Dpr genes were found in the undifferentiated limb mesenchyme, progenitor of chondrocytes, perichondrium and tendons. These results suggest that Dpr genes are good candidates to a new set of markers in chicken limb development. Furthermore, our phylogenetic analysis revealed that the Dprs arose late during the deuterostomes evolution and allowed the identification of a new Dpr paralog (Dpr4), meaning that a repertoire of four Dact genes is found in vertebrates. Thus, our work will provide the basis for molecular studies in order to establish the role of each individual member of this family as well as how the set of Dpr proteins can interact and cooperate to modulate different molecular signaling pathways in different cellular contexts
Doutorado
Biologia Tecidual
Doutora em Biologia Celular e Estrutural
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Adams, Jason Samuel. "Regulation of Sensory Neurogenesis in the Trigeminal Placode: Notch Pathway Genes, Pax3 Isoforms, and Wnt Ligands." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3144.
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This dissertation is divided into three chapters, each discussing the study of different regulatory molecules involved in sensory neurogenesis occurring in the trigeminal placode. Chapter one is a spatiotemporal description of Notch pathway genes in chick opV placode by stage-specific expression analysis, showing expression of many Notch pathway genes and effectors in the opV placode. Notch pathway gene expression is primarily confined to the ectoderm with highest expression of these genes at the beginning stages of peak neuronal differentiation. This information preceded studies of the functional roles that Notch signaling has in the opV placode and how it may affect the transcription factor, Pax3. Chapter two is a study of the transcription factor Pax3 and its role in opV placode development and sensory neuron differentiation. Pax3 is known to activate or repress gene transcription, and its activity may be dependent on the splice variant or isoform present. We show through RT-PCR that alternative splice forms of Pax3 are present at stages of chick development corresponding to cellular competence, cellular differentiation and ingression, and cellular aggregation. We have named these splice forms, Pax3V1 and Pax3V2. Using quantitative RT-PCR we show that Pax3V2 is consistently expressed at lower levels compared to Pax3 during cellular competence and differentiation. In order to determine the function of the three splice forms, we misexpressed them in the opV placode and analyzed the effect on neurogenesis. We looked at markers for neuronal differentiation of targeted cells after in ovo electroporation of Pax3, Pax3V1, and Pax3V2, which showed a significant difference between the control and each construct, but not between the groups of constructs. To enhance the process of neurogenesis we exposed the electroporated embryos to DAPT, a Notch signaling inhibitor that enhances sensory neurogenesis. Using this method we found that misexpression of Pax3 and Pax3V1 resulted in cells failing to differentiate, while Pax3V2 misexpression more closely resembles the neuronal differentiation seen in controls. These results show that the Pax3V2 isoform allows for neuronal differentiation of opV placodal cells after misexpression, while the Pax3 isoform and the Pax3V1 isoform block neuronal differentiation. Chapter three is a study of the necessity of Wnt signaling originating from the neural tube to induce Pax3 expression in the opV placode. A double knockout of Wnt1 and Wnt3a was produced to determine the necessity of these genes in opV placode development. Pax3 expression in the opV placode at E8.5 and E9.5 was markedly reduced in the double mutants when compared to wild type mice. This study shows that Wnt1 and Wnt3a genes are necessary for normal Pax3 expression, but that other signals may contribute to its induction.
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Pedrosa, Angelica Vasconcelos 1986. "Análise comparativa da expressão dos genes Vangl1 e Vangl2 durante a ontogênese da galinha (Gallus gallus)." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317674.
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Orientador: Lúcia Elvira AlvaresDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: A correta padronização do corpo do embrião requer a atividade de diferentes vias de sinalização. Dentre elas, uma que se destaca é via de sinalização Wnt de polaridade celular planar (Wnt/PCP), que é responsável pelo controle da polaridade celular e pela organização celular de diversos tecidos nos animais. Uma vez interrompida, a via Wnt/PCP pode causar falhas no fechamento do tubo neural, provocando defeitos congênitos. Em seres humanos, mutações em componentes-chave da via Wnt/PCP como as proteínas codificadas pelos genes Vangl1 e Vangl2 têm sido associadas à graves malformações geradas por falhas no fechamento do tubo neural. Estruturalmente, ambos os genes Vangl1 e Vangl2 codificam proteínas de superfície transmembranares, essenciais para o desenvolvimento apropriado do embrião. O presente trabalho teve como objetivo a caracterização do padrão de expressão dos genes Vangl1 e Vangl2 durante a embriogênese de Gallus gallus. Ensaios de hibridação in situ em embrião inteiro (whole mount) e cortes em vibratómo foram realizados com a finalidade de estabelecer temporal e espacialmente o padrão de expressão dos genes Vangl1 e Vangl2. Como resultado, observou-se que estes genes são expressos durante as etapas de gastrulação, neurulação e no início da organogênese do desenvolvimento embrionário de Gallus gallus. No início da gastrulação, os genes Vangl1 e Vangl2 possuem domínios de expressão comuns nos embriões de galinha, uma vez que ambos são expressos na linha primitiva, nódulo de Hensen e crescente cardiogênico. Contudo, nossos dados revelaram particularidades na expressão destes genes, uma vez que há uma predominância dos transcritos de Vangl1 na região posterior da linha primitiva, enquanto Vangl2 apresenta uma expressão uniforme ao longo desta estrutura. Em adição, enquanto Vangl1 é expresso na notocorda e em toda a extensão do nódulo de Hensen, Vangl2 é expresso no entorno desta estrutura. Ao longo da neurulação e na organogênese inicial, ambos os genes Vangl são expressos de maneira similar, em domínios que abrangem a placa, as pregas e o tubo neural. Outros importantes domínios de expressão dos Vangl correspondem às vesículas ópticas e óticas, às vesículas encefálicas particularmente na região das flexuras encefálicas, aos diferentes tipos de mesoderma (paraxial, intermediário e lateral) e ao assoalho da faringe. Ao comparar os resultados obtidos por hibridação in situ em galinha ao um levantamento bibliográfico sobre outros vertebrados, observou-se uma sobreposição dos domínios-chave de expressão nos diferentes organismos, demonstrando a conservação filogenética da atividade destes genes e sugerindo uma possível conservação funcional. Desta forma, nossos dados sugerem que os genes Vangl desempenham um importante papel no desenvolvimento embrionário de aves, possivelmente coordenando os movimentos morfogenéticos durante a gastrulação, bem como a formação da placa neural e posterior dobramento e fechamento do tubo neural, além de outros processos da embriogênese de aves
Abstract: The correct patterning of the embryo's body requires the activity of different signaling pathways. Among them, one that stands out is the Wnt Planar Cell Polarity Signaling Pathway (Wnt/PCP), which is responsible for controlling the cell polarity and cellular organization of many tissues in animals. Failures in the Wnt/PCP signaling can cause neural tube birth defects. In humans, mutations in key components of the Wnt/PCP as the Vangl1 and Vangl2 molecules were identified in patients with neural tube defects. Structurally, both Vangl1 and Vangl2 genes encode transmembrane surface proteins similar, which are essential to proper development. The present study aimed to characterize the expression pattern of Vangl1 and Vangl2 genes during embryogenesis in Gallus gallus. Whole-mount in situ hybridization assays and vibratome sectioning of embryos were conducted in order to establish the spatial and temporal expression pattern of Vangl1 and Vangl2 genes. Our results showed that these genes are expressed during gastrulation, neurulation and early organogenesis in Gallus gallus. At the onset of Gastrulation, Vangl1 and Vangl2 genes have common areas of expression in chicken embryos, since both are expressed in the primitive streak, Hensen's node and cardiogenic crescent. However, our data showed particularities in the expression of these genes, since there is a predominance of Vangl1 transcripts in the posterior region of the primitive streak while Vangl2 has a uniform expression throughout that structure. In addition, while Vangl1 is expressed in the notochord and in the full length of the Hensen's node, Vangl2 is expressed only around this structure. Throughout neurulation and early organogenesis, both Vangl genes are expressed in a similar manner on the neural plate, neural groove, neural folds and in the neural tube. Other important areas of Vangl expression correspond to optical and otic vesicles, the brain vesicles, the different types of mesoderm (paraxial, intermediate and lateral) and the floor of the pharynx. By comparing the chicken expression of Vangl genes with other vertebrates, we notice that there are overlapping expression patterns among key areas among different organisms, showing a phylogenetic conservation of expression domains and suggesting a possible functional conservation. Overall, our data suggests that Vangl genes play an important role in embryonic development of bird, possibly by coordinating the morphogenetic movements during gastrulation, as well as the formation of neural tube, among other processes during the birds embriogenesis
Mestrado
Biologia Celular
Mestra em Biologia Celular e Estrutural
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Lacour, Floriane. "Contrôle des voies de signalisation Wnt par R-spondin1 au cours de la régénération du muscle squelettique adulte." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCB035/document.
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Le muscle squelettique adulte a une importante capacité à se régénérer après une lésion. La régénération musculaire dépend de divers signaux moléculaires tels que l’activation de la signalisation Wnt dans les cellules souches musculaires, appelées cellules satellites. Les protéines R-spondins (Rspo) composent une famille de quatre protéines qui ont un rôle d’activateurs/potentialisateurs sur les voies Wnt dans les cellules souches de différents tissus. Bien qu’il soit connu que ces protéines sont importantes pour la régénération de ces tissus, leur rôle dans la myogenèse régénérative n’a pas été étudié à ce jour. L’expression génique de R-spondin1 étant sur-régulée par Pax7, le marqueur des cellules satellites, nous avons émis l’hypothèse que R-spondin1 participe à la régénération musculaire. Nous avons, tout d’abord, isolé les cellules souches musculaires des modèles murins d’invalidation constitutive pour Rspo1 et avons observé qu’une déficience de R-spondin1 n’altère pas le cycle cellulaire de ces cellules. Cependant, une altération de l’expression de Rspo1 induit un défaut global de la cinétique de différenciation myogénique. Nous montrons que R-spondin1 inhibe la fusion des cellules musculaires puisque les myotubes déficients pour R-spondin1 possèdent un plus grand nombre de noyaux. Nous avons ensuite induit la régénération du muscle squelettique Tibalis Antérieur par une injection de Cardiotoxine et nous avons analysé les muscles à différents temps de régénération. Nos données prouvent qu’en l’absence de R-spondin1, les cellules souches présentent un retard de différenciation alors qu’elles possèdent une plus grande capacité de fusion, ayant pour conséquence une hypertrophie des myofibres dans le muscle. Concordant au rôle de R-spondin dans les cellules souches intestinales ou dans le follicule pileux, la protéine R-spondin1 stimule l’expression des gènes cibles de la voie Wnt canonique dans les cellules souches musculaires. Nous avons mis en évidence que R-spondin1 potentialise la voie Wnt canonique et régule négativement l’activation de la voie non-canonique dans les cellules. Nos résultats démontrent que la protéine R-spondin1 contribue à la régénération du muscle squelettique adulte par la régulation de l’activation des voies WntAdult mammalian skeletal muscles have the remarkable ability to repair after injury. Muscle regeneration depends on various cellular and molecular responses, such as activation of Wnt signaling pathways in muscle stem cells called satellite cells. R-spondin (Rspo) proteins are able to potentiate Wnt signaling pathways in vivo in many stem cells and play important role for regeneration of several tissues. The role of R-spondin in injury-induced myogenesis has not been studied. Given that R-spondin1 gene expression is up-regulated by Pax7, the satellite cell-specific transcription factor, we explored the hypothesis that R-spondin1 plays a role during skeletal muscle regeneration. We firstly isolated primary myoblasts from Rspo1 constitutive knock-out mice and observed that a depletion of Rspo1 did not alter cell cycle of these cells. However, a lack of R-spondin1 on cells resulted in global alteration of differentiation kinetics. We found that R-spondin1 inhibits muscle cell fusion, as Rspo1 knock-out myotubes contain an higher number of myonuclei. Then, we injured the Tibialis Anterior (TA) muscle of Rspo1-null mice and littermates controls by Cardiotoxin injection and analyzed muscle regeneration at different time points following injury. Our data show that R-spondin1 removal results in a delay of stem cell differenciation. In contrast, a R-spondin1 deficiency leads to better cell capacity to fuse to dommaged myofibers, giving rise to myofiber hypertrophy. As with other tissue-specific stem cells, such as hair follicle or intestinal crypt stem cells, R-spondin1 potentiates canonical Wnt signaling target genes expression in muscle stem cells. We proved that R-spondin1 potentiates canonical Wnt signaling target genes expression and negatively regulates non-canonical signaling in muscle stem cells. Our results demonstrate that R-spondin1 is crucial for adult muscle regeneration through a tighly cross-talk regulation between Wnt signalings
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Ali, Taccyanna Mikulski. "Perfil de expressão de genes da via Wnt/beta-catenina em timócitos e linfócitos T CD4+ de camundongos BALB/c." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5146/tde-06112015-144437/.
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INTRODUÇÃO: A molécula HIG2 pode atuar como agonista da via Wnt/beta-catenina, pois se liga ao receptor Frizzled 10 e induz a expressão de genes da mesma. Dados recentes do nosso grupo mostraram expressão diferencial do gene HIG2 em células mononucleares do sangue periférico e em especial linfócitos T CD4+ naïve, mas não em células diferenciadas de memória em indivíduos sadios. Também observamos in vitro em linfócitos T CD4+ de indivíduos saudáveis que o peptídeo sintético HIG2 induziu a ativação da via Wnt/beta-catenina, produção de HIG2 e outros produtos da via, além da proliferação de células T CD4+ naïve sugerindo um papel do HIG2 na proliferação homeostática de linfócitos T CD4+. HIPÓTESE: Como as células T CD4+ naïve são diretamente exportadas pelo timo, os níveis aumentados de HIG2 neste tipo celular sejam decorrentes da ativação da via Wnt/?-catenina nos estágios tardios da diferenciação de timócitos. Portanto, as células T CD4+ naïve e timócitos simples positivos para CD4 (SP CD4) apresentariam perfil semelhante de expressão de HIG2 e genes da via Wnt/beta-catenina, incluindo receptores, fatores de transcrição, genes estruturais da via e alvos quando comparadas as demais populações celulares. OBJETIVO: Avaliar a expressão de HIG2 e outros genes da via Wnt/beta-catenina em timócitos e linfócitos T CD4+ naïve e memória de camundongos. MÉTODOS: Isolamos timócitos duplo negativos (DN), timócitos duplo positivos (DP), simples positivos para CD4 e CD8 (SP CD4 e SP CD8) de timo e também células T CD4+ naïve e memória do baço dos mesmos camundongos pelo procedimento de citometria de fluxo. Analisamos a expressão de vários genes da via Wnt/beta-catenina por PCR em tempo real. RESULTADOS: Em timócitos DN há expressão significativa dos genes que codificam para Frizzled 6, LRP5, TCF-1 e TCF-4 em relação as outras populações celulares. Nos timócitos DP há maior expressão dos genes que codificam para LRP5, LRP6, beta-catenina, GSK-3beta, TCF-1 e Bcl-XL em relação às demais populações. Em timócitos SP CD4 foi detectada expressão diferencial de genes que codificam para Frizzled 10, LRP6, beta-catenina, LEF-1 e HIG2 enquanto que na população de timócitos SP CD8 não observamos expressão significativa de nenhum gene da via Wnt/beta-catenina. Nas células T CD4+ naïve há expressão significativa de Frizzled 5 e Frizzled 10 quando comparadas a timócitos SP CD8 e células T CD4+ de memória . Já nos linfócitos T CD4+ de memória, detectamos maior expressão de Frizzled 6, TCF-4, Bcl-XL e ciclina D1 em relação as demais populações. CONCLUSÃO: Cada população apresenta um perfil distinto de expressão gênica. As maiores semelhanças ocorrem entre os timócitos DN e DP onde as principais diferenças são a expressão de Frizzled 6 e Ciclina D1.Os timócitos SP CD4 e as células T CD4+ naïve não apresentaram níveis semelhantes de expressão gênica de elementos da via Wnt canônica, o que não corrobora a hipótese de que o perfil transcripcional de timócitos SP CD4 e linfócitos T CD4+ naïve é semelhante. Ainda, não observamos expressão aumentada de HIG2 em linfócitos T CD4+ naïve comparados aos de memória, o que contrasta com os resultados obtidos anteriormente por nosso grupo com amostras humanas sugerindo que camundongos não regulam a expressão de HIG2 em linfócitos T CD4+ como os seres humanosINTRODUCTION: HIG2 molecule can act as an agonist of Wnt/?-catenin pathway, because it able to bind to Frizzled 10 receptor and induce the expression of the genes related to this pathway. Recent data from our group have shown differential expression of the HIG2 gene in peripheral blood mononuclear cells, and particularly in naive CD4 + T cells, but not in memory T cells in healthy individuals. We have also observed that inducing the CD4 + T lymphocytes from healthy individuals with HIG2 synthetic peptide in vitro, led to the activation of Wnt/beta-catenin pathway, HIG2 production and expression of other target genes of this pathway and the proliferation of naïve CD4 + T cells, suggesting that HIG2 may play a role in homeostatic proliferation of CD4+ T cells. HYPOTHESIS: As naïve CD4 + T cells are directly exported from the thymus, we have hypothesized that increased levels of HIG2 in this cell type is due to the activation of Wnt/beta-catenin pathway in the later stages of thymocyte differentiation. Therefore, naïve CD4 + T cells and CD4 single-positive thymocytes (CD4 SP) may share a similar pattern of gene expression of HIG2 and Wnt/beta-catenin genes (genes that encodes receptors and co-receptors, transcription factors, structural and target genes) when compared to other cell populations. AIM: our major aim is to evaluate the expression of HIG2 and other genes of the Wnt/beta-catenin in thymocytes, naïve CD4 + T lymphocytes and memory CD4+ T cells from mice. METHODS: We have isolated thymocytes double negative (DN) T cells, positive double positive (DP) T cells, CD4 and CD8 single-positive thymocytes (CD4 SP and CD8 SP) of thymus from BALB/c mice and we have also isolated naïve CD4 + T cells and memory CD4+ T cells of the spleen from the same mice we have used the thymus. We have analysed the expression of several genes of Wnt/beta-catenin by real time PCR RESULTS: In DN cells there was expression of the Frizzled 6, LRP5, TCF-1 and TCF-4 genes compared to other cell populations. In DP thymocytes it could be observed a greater expression of LRP5, LRP6, beta-catenin, GSK-3beta, TCF-1 and Bcl-XL genes compared to other populations. In CD4 SP thymocytes, it was detected differential expression of the Frizzled 10, LRP6, beta-catenin, LEF-1 HIG2 genes and in CD8 SP cells we could not observe significant expression of any gene of Wnt/?-catenin pathway. In naïve CD4 + T cells there was a significant expression of Frizzled5 and Frizzled 10 genes when compared to all the samples. In memory CD4 + T cells, we have detected higher expression of Frizzled 6, TCF-4, Bcl-XL and cyclin D1 genes than in any other populations. CONCLUSION: Each population has a distinct gene expression pattern. The biggest similarities occur between DN and DP thymocytes where the main differences are the expression of Frizzled 6 and cyclin D1.However, the pattern of gene expression in SP thymocytes is not similar to those presented by naïve CD4+ T cells. Moreover, we have not observed increased expression of HIG2 in naïve CD4 + lymphocytes compared to memory CD4+ T cells, which contrasts the results obtained previously by our group with human samples suggesting that mice might not regulate the HIG2 expression in CD4 + T lymphocytes as human beings do
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SCHWAB, KRISTOPHER R. "EXPRESSION MICROARRAY ANALYSIS OF RENAL DEVELOPMENT AND HUMAN RENAL DISEASE." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1157651859.
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Wong, Yin-chi Betty, and 黃妍之. "Significance of LRP6 coreceptor upregulation in the aberrant activation of Wnt signaling in hepatocellular carcinoma." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41757865.
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Omar, Wan Adnan Wan. "DNA methylation in bowel cancer and the effect of folic acid supplementation on methylation of WNT antagonistic genes." Thesis, University of Newcastle Upon Tyne, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627738.
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Deshpande, Rashmi Jayant. "POP-1/CETCF-1 has multiple functions in P ectoblast development." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1133378295.
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Segati, Kelly Deyse. "Análise da metilação dos genes SOX17, DKK3 e SFRP2, tipos de HPV e associação com a origem e o estadiamento do câncer de colo uterino." Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7757.
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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
Cervical cancer is caused by persistent high-risk HPV infection. In addition, genetic and epigenetic changes such as the silencing of Wnt signaling pathway inhibitor genes appear to be essential for the development and progression of the disease. This study aimed to analyze the prevalence of HPV infections in cervical cancer and to verify the associations between age, histological type, degree of tumor differentiation and the presence of methylation DKK3, SOX17 and SFRP2. This is a cross-sectional study including cases of cervical cancer, distributed in diagnoses of squamous cell carcinomas and adenocarcinomas. The samples were assayed for 25 HPV genotypes using the INNOLipa® kit, then performed M-PCR to identify the presence of methylation in the promoter region of the genes DKK3, SOX17 and SFRP2. The results of the research showed that the age is significantly lower for women with cervical adenocarcinomas compared to those with a diagnosis of squamous cell carcinoma. Infections with genotypes 18 and 45 were associated with the diagnosis of adenocarcinomas in women younger than 50 years. Methylation of inhibitors of the Wnt signaling pathway and HPV infections 16, 18 and 45 are frequent events during multistage carcinogenesis, however, only a significant association with SFRP2 methylation was observed. The methylation of gene promoter SOX17 was related to lower cervical cancer severity but not to HPV types. Adenocarcinomas were significantlyassociated with HPV infections 16, 18 and 45, and demonstrated a borderline association with DKK3 and SOX17 methylation. In summary, the results of the present study contribute to a better understanding of carcinogenesis of the cervix in the Center-West of Brazil.
O câncer de colo uterino é causado pela infecção persistente por HPV de alto risco oncogênico. Em adição, as alterações genéticas e epigenéticas como o silenciamento dos genes inibidoresda via de sinalização Wnt parecem ser essenciais para o desenvolvimento e progressão da doença. Esse estudo teve como objetivo analisar a prevalência de infecções por genótipos específicos de HPV em câncer de colo uterino e verificar as associações entre a idade, tipo histológico, o grau de diferenciação tumoral e a presença da metilação na região promotora dos genes DKK3, SOX17 e SFRP2. Trata-se de um estudo de corte transversal incluindo casos de câncer de colo uterino, distribuídos em diagnósticos de carcinomas de células escamosas e adenocarcinomas. As amostras foram testadas para 25 genótipos de HPV utilizando o kit INNOLipa®, em seguida foram submetidas a M-PCR para identificar a presença da metilação na região promotora dos genes DKK3, SOX17 e SFRP2. Os resultados da pesquisa mostraram que a idade é significativamente menor em mulheres com adenocarcinomas cervicais comparadas com aquelas com diagnóstico de carcinoma de células escamosas. A infecção por genótipos 18 e 45 foram positivamente associadas ao diagnóstico de adenocarcinomas em mulheres com idade menor que 50 anos. A metilação dos inibidores da via de sinalização Wnt e as infecções por HPV 16, 18 e 45 são eventos frequentes durante a carcinogênese em várias etapas, no entanto, apenas foi observada associação significativa com a metilação de SFRP2. A metilação da região promotora de SOX17 foi relacionada com menor gravidade do câncer de colo uterino, mas não com tipos de HPV. Os adenocarcinomas apresentaram associação significativa com infecções por HPV 16, 18 e 45, além de demonstrar uma associação limítrofe com a metilação de DKK3 e SOX17. Em resumo, resultados do presente estudo contribuem para o melhor entendimento da carcinogêneses do colo uterino na região Centro-Oeste do Brasil.
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Melichar, Heather J. "SOX13, A γδ T Cell-Specific Gene, Is a WNT-Signaling Antagonist Regulating T Cell Development: A Dissertation." eScholarship@UMMS, 2006. https://escholarship.umassmed.edu/gsbs_diss/251.
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Mature αβ and γδ T cells arise from a common precursor population in the thymus. Much debate has focused on the mechanism of T cell lineage choice made by these multi-potential precursor cells. It is widely believed that the decision of these precursor cells to commit to the γδ or αβ T cell lineages is regulated primarily by a specific instructive signal relayed through the appropriate T cell receptor. Contrary to this model, we present evidence for a TCR-independent lineage commitment process. Comparison of global gene expression profiles from immature αβ and γδ lineage thymocytes identified Sox13, an HMG-box transcription factor, as a γδ T cell-specific gene. Unlike other HMG-box transcription factors such as TCF1, LEF1 and SOX4, that are critical for proper αβ T cell development, Sox13 expression is restricted to early precursor subsets and γδ lineage cells. Importantly, SOX13 appears to influence the developmental fate of T cell precursors prior to T cell receptor expression on the cell surface. Transgenic over-expression of Sox13 in early T cell precursors strongly inhibits αβ lineage development, in part, by inhibiting precursor cell proliferation and concomitantly, leading to increased cell death among αβ lineage subsets. Steady-state γδ T cell numbers, however, appear unaffected. Strikingly, the DP αβ lineage cells that do develop in Sox13 transgenic mice are imprinted with a γδ- or precursor-like molecular profile, suggesting that SOX13 plays an active role in the lineage fate decision process or maintenance. Sox13-deficient mice, on the other hand, have selectively reduced numbers of γδ thymocytes, indicating that SOX13 is essential for proper development of γδ T cells. We present additional data demonstrating that SOX13 is a canonical WNT signaling antagonist modulating TCF1 activity, raising a strong possibility that WNT signals, and their modulators, are at the nexus of γδ versus αβ T cell lineage commitment.
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Fracalossi, Ana Carolina Cuzzuol [UNIFESP]. "Carcinogênese bucal quimicamente induzida pela 4-nitroquinolina 1-óxido em ratos: possíveis biomarcadores envolvidos em sua patogênese." Universidade Federal de São Paulo (UNIFESP), 2010. http://repositorio.unifesp.br/handle/11600/9195.
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Previous issue date: 2010-11-24Objetivos: este trabalho teve como objetivo investigar mutacoes nos exons 1 e 2 do Hras e K-ras, bem como, a imunoexpressao do H-ras, Ki-67, alfa-SMA, metaloproteinases 2 e 9 (MMP-2 e MMP-9) e a via Wnt/ƒÀ-catenina (Wnt1, Frizzled-1, Wnt5a, Frizzled-5 e ƒÀ-catenina) durante a carcinogenese bucal quimicamente induzida pela 4-nitroquinolina 1-oxido (4NQO) em ratos. Material e Metodos: Ratos Wistar machos foram distribuidos em tres grupos de 10 animais cada e tratados com 50 ppm de 4NQO, via bebedouro, durante 4, 12 e 20 semanas. Dez animais foram utilizados como controle. Resultados: apesar da ausencia de alteracoes histopatologicas no epitelio apos 4 semanas de exposicao ao cancerigeno, Ki-67 e Wnt1 mostraram alta expressao no epitelio oral gnormal h; expressao de Ki-67, MMP-2 e MMP-9 foi detectada tanto nas lesoes pre-neoplasicas quanto nos carcinomas espinocelulares bem diferenciados induzidos apos 12 e 20 semanas de tratamento com a 4NQO, respectivamente; alfa-SMA revelou-se diferencialmente expressa nos carcinomas espinocelulares. Nenhuma diferenca significativa (p>0.05) foi encontrada na expressao de H-ras, Frizzled-1, Frizzled-5 e ƒÀ-catenina, em todos os momentos avaliados. Do mesmo modo, nenhuma mutacao foi encontrada nos genes H-ras e K-ras. Conclusoes: de acordo com os resultados encontrados, o aumento do status proliferativo a partir do Ki-67 e expressao de Wnt1, MMP-2 e MMP-9 estao associados ao risco e a progressao do cancer bucal, enquanto que mutacoes no gene Ras parecem nao estar envolvidas na carcinogenese lingual induzida pela 4NQO.
TEDE
BV UNIFESP: Teses e dissertações
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Guo, Long. "Functional investigation of a non-coding variant associated with adolescent idiopathic scoliosis in zebrafish: elevated expression of the ladybird homeobox gene causes body axis deformation." Kyoto University, 2016. http://hdl.handle.net/2433/215453.
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Final publication is available at http://www.plosgenetics.org/article/related/info%3Adoi%2F10.1371%2Fjournal.pgen.1005802Kyoto University (京都大学)
0048
新制・課程博士
博士(医学)
甲第19627号
医博第4134号
新制||医||1016(附属図書館)
32663
京都大学大学院医学研究科医学専攻
(主査)教授 萩原 正敏, 教授 松田 秀一, 教授 瀬原 淳子
学位規則第4条第1項該当
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Low, Keri Lynn. "FGF4 and Wnt5a/PCP signaling promote limb outgrowth by polarizing limb mesenchyme /." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1612.pdf.
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Merenda, Alessandra. "Development of a new screening system for the identification of RNF43-related genes and characterisation of other PA-RING family members." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267982.
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The E3 ubiquitin ligase RNF43 (RING finger protein 43) is an important negative modulator of the WNT signalling pathway that acts at the plasma membrane by targeting Frizzled and its co-receptor LRP for degradation. In the small intestine, this prevents uncontrolled expansion of the stem cell compartment and so it is essential to the maintenance of normal tissue homeostasis. However, despite its crucial role in fine-tuning the WNT pathway and its role as a tumour suppressor, it is unclear whether RNF43 has further binding partners and what their functional relevance is to the modulation of WNT signalling. Here, I describe the development of a new screening strategy which combines CRISPR/Cas9 technology with 3D-intestinal organoid culture for the identification of novel molecular interactors of RNF43. Overall, this study and the technology developed provide a tool to enable the detailed description of the mechanism of action of RNF43, which is important not only in order to increase our understanding of WNT pathway regulation but also to gain potential new insights into RNF43 paralogs, by analogy. The investigation of paralogs is crucial as RNF43 belongs to a newly identified family of E3 ubiquitin ligases, named the PA-RING family, whose members are still poorly characterised. The majority of PA-RING family members have not been linked to any signalling pathway, most of their targets are still unknown and in many cases their in vivo function has not been addressed. In this context, my work has specifically focused on the investigation of the potential involvement of additional PA-RING family members in WNT pathway modulation and also on target identification for selected members. The results summarised in this dissertation show that no other PA-RING family member plays a prominent role in WNT pathway modulation aside from Rnf43 and its homologue Znrf3, however, different classes of adhesion molecules are likely to be regulated by certain of these E3 ligases. In conclusion, my work has contributed to unravelling previously unexplored aspects of this protein family, with particular regard to RNF43 and its mechanism of action. Thanks to this original approach, it was possible to identify potential new players involved either in membrane clearance of Frizzled or in RNF43 maturation. In particular, my thesis focuses on the characterisation of the role of DAAM in RNF43-mediated Frizzled internalisation.
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Belle, Martin. "Rôle des voies Wnt dans la régulation des gènes de la myéline et le cytosquelette des cellules de Schwann." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00714665.
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Les cellules de Schwann sont responsables de la myélinisation du système nerveuxpériphérique. C'est un phénomène complexe et finement régulé. En effet, des altérationsde l'expression touchant les protéines de la myéline périphérique (P0 et PMP22)peuvent provoquer des pathologies comme la Charcot‐Marie‐Tooth. Par ailleurs, lescellules de Schwann subissent d'importantes modifications de leur cytosquelette aucours du processus de myélinisation.Nous avons identifié la voie Wnt/β‐caténine comme directement impliquées dansla régulation de l'expression des gènes de la myéline P0 et PMP22 à la fois in vitro maiségalement in vivo. De plus, nous avons initié la démonstration de l'implication de la voieWnt non canonique au cours de ce même processus. Par ailleurs, nous avons montré queles ligands Wnts aussi bien canoniques que non canoniques pouvaient provoquerl'allongement des extensions des cellules de Schwann. Le chlorure de lithium est uninhibiteur de la GSK3β, mimant l'activation de la voie Wnt/β‐caténine. Il provoque unimportant allongement des cellules de Schwann accompagné de profonds remaniementsde l'architecture interne. Par la suite nous nous sommes intéressés aux effets d'unelésion sur la remyélinisation. La voie Wnt/β‐caténine est réactivée par une lésion in vitrotandis que le lithium accélère la récupération fonctionnelle du battement des vibrissesde souris après pincement du nerf facial, améliore les structures de la gaine de myélineet induit l'expression des gènes de la myéline in vivo.ConclusionNotre travail a mis en évidence le rôle majeur des voies Wnt canoniques et noncanoniques dans la régulation de l'expression de gènes de la myéline et dans lecytosquelette des cellules de Schwann.
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Pachón, Andrés Felipe Aristizábal. "Alterações Genéticas e Epigenéticas dos Genes do Complexo de Destruição de β-Catenina e Perfil Transcricional dos Componentes da Via de Sinalização Wnt no Câncer de Mama." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/17/17135/tde-28072015-100134/.
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O câncer de mama é a neoplasia responsável pelo maior número de mortes em mulheres no Brasil, portanto, é importante encontrar novos marcadores específicos e de diagnóstico precoce, utilizando procedimentos simples e rápidos. A via de sinalização Wnt regula importantes funções celulares como proliferação, sobrevida e adesão. Esta via está associada com os processos de iniciação e progressão em muitos tipos tumorais, como câncer de cólon familiar, melanoma e pulmão; sendo que mutações em β-Catenina (CTNNb1) explicam só 30% dos casos de sinalização aberrante encontrada no câncer de mama, indicando que existem outros componentes e/ou reguladores da via que possam estar envolvidos. O objetivo deste trabalho foi avaliar as variantes genéticas e epigenéticas nos genes do complexo de degradação de β-Catenina num grupo de pacientes com câncer de mama e num grupo controle; e determinar os perfis de transcrição dos componentes da via de sinalização Wnt e da molécula de expressão exclusiva do epitélio mamário, a Mamaglobina Humana (MGA), assim como associar estes resultados com as características clínicas, histológicas e patológicas do tumor. Para atingir este objetivo foram coletadas amostras de sangue periférico de 102 mulheres com câncer de mama e 102 mulheres sadias como grupo controle. A avaliação das variantes rs465899 do gene APC, rs2240308 e rs151279728 do gene AXIN2, rs5030625 do gene CDH1 e rs334558 do gene GSK3, foi realizada por meio de PCR-RFLPs e sequenciamento, a análise dos perfis de metilação dos promotores pela MS-PCR. A RT-qPCR foi usada para determinar os níveis de expressão dos componentes da via e a MGA. As variantes rs2240308 e rs151279728 do gene AXIN2 mostraram uma forte associação com o risco de desenvolver o câncer de mama. Um aumento significativo foi observado no nível de expressão de AXIN2 no grupo de mulheres com câncer de mama. Análises adicionais mostraram perfis de expressão diferencial dos genes APC, AXIN2, CTNNB1, GSK3 e CSNK1A1 associado ao status dos receptores hormonais e histogênese tumoral. MGA foi identificado exclusivamente em 38% dos pacientes com câncer de mama e foi associada com a progressão da doença. Este é o primeiro estudo que relaciona uma variante do gene AXIN2 com o câncer de mama na população brasileira. As variantes avaliadas do gene AXIN2 são marcadores promissores de susceptibilidade ao câncer de mama na população estudada, sendo importante, a avaliação desta variante genética na população e determinar o seu real efeito no processo de iniciação e/ou progressão do câncer de mama.Background: Wnt/β-catenin signaling pathway is an important regulator of cellular functions such as proliferation, survival and cell adhesion. This pathway is associated with tumor initiation and progression; -catenin (CTNNB1) mutations explains only 30% of aberrant signaling found in breast cancer, indicating that other components and/or regulating of the Wnt/β-catenin pathway may be involved. Objective: The objective of the study was to evaluate the APC rs465899, AXIN2 rs2240308 and rs151279728, CDH1 rs5030625 and GSK3 rs334558 polymorphisms, APC, AXIN2, CDH1 and GSK3 promoter methylation status and expression profile of -Catenin destruction complex genes and MGA in peripheral blood of breast cancer patients. Methods: We collected peripheral blood samples from 102 breast cancer and 102 healthy subjects. The identification of the mutation was performed using PCR-RFLPs and DNA sequencing. MSP and HRM-MS was used to measure promoter methylation and RT-qPCR to determine expression profile. Results: We found significant association of AXIN2 rs2240308 polymorphism with breast cancer. Increased risk was observed even after stratification based on clinicpathological characteristics. AXIN2 rs151279728 polymorphism was found only in 9 breast cancer patients, but none in control group subject. APC and CDH1 polymorphisms were not associated with breast cancer. GSK3 polymorphism was weak associated with breast cancer and heterozygous status was associated with breast cancer protection after group stratification. APC and CDH1 promoter methylation in breast cancer patients was found. Significant increase was observed in AXIN2, CTNNB1 and GSK3 level expression in breast cancer patients. APC was down-regulated in breast cancer patients. Further analyses, showed APC, AXIN2, CTNNB1, GSK3 and CSKN1A1 gene expression associated to receptor status and histological type. MGA was found only in breast cancer patients and was associated with cancer progression. Conclusion: The present study reports, for the first time, that AXIN2 genetic defect and -catenin destruction complex expression disturbance may be found in breast cancer patients, providing additional support to the role of Wnt/-catenin pathway dysfunction in breast cancer tumorigenesis. However, the functional consequence of this genetic alteration remains to be determined. In another hand MGA was determined like a good biomarker for diagnosis and prognosis outcome.
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Scholtka, Bettina, Mandy Schneider, Ralph Melcher, Tiemo Katzenberger, Daniela Friedrich, Kornelia Berghof-Jäger, Wolfgang Scheppach, and Pablo Steinberg. "A gene marker panel covering the Wnt and the Ras-Raf-MEK-MAPK signalling pathways allows to detect gene mutations in 80% of early (UICC I) colon cancer stages in humans." Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2010/4458/.
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Background: Very recently a gene marker panel that allows the mutational analysis of APC, CTNNB1, B-RAF and K-RAS was conceived. The aim of the present study was to use the 4-gene marker panel covering the Wnt and Ras-Raf-MEK-MAPK signalling pathways to determine the percentage of sporadic colorectal carcinomas (CRC) carrying at least one of the four above-mentioned genes in a mutated form alone and/or in combination with microsatellite instability (MSI) and to compare the sensitivity of the gene marker panel used in this study with that of gene marker panels previously reported in the scientific literature. Methods: CTNNB1 and B-RAF were screened by PCR-single-strand conformation polymorphism analysis and K-RAS gene mutations by restriction fragment length polymorphism analysis. For the mutational analysis of the APC gene mutation cluster region (codons 1243–1567) direct DNA sequencing was performed. The U.S. National Cancer Institute microsatellite panel (BAT25, BAT26, D2S123, D5S346 and D17S250) was used for MSI analysis. Results: It could be shown that about 80% of early stage CRC (UICC stages I and II) and over 90% of CRC in the UICC stage IV carried at least one mutated gene and/or showed MSI. No significant increase in the gene mutation frequencies could be determined when comparing tumours in the UICC stage I with those in UICC stage IV. Conclusions: When compared with previously published gene marker panels the 4-gene marker panel used in the present study shows an excellent performance, allowing to detect genetic alterations in 80–90% of human sporadic CRC samples analyzed.
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Melo, Natália Cruz e. "Validação de genes diferencialmente expressos identificados em células MCF-7 com diferenças de expressão de PAR-4 (Prostate Apoptosis Response-4) antes e após a exposição de docetaxel." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/5/5155/tde-12042016-150215/.
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O PAWR (Prostate apoptosis response- 4) também conhecido como PAR-4 é um gene pró-apoptótico identificado em células de câncer de próstata quando expostas a estímulos apoptóticos. A expressão de PAR-4 pode aumentar a sensibilidade da célula a apoptose, incluindo células de câncer de mama. Ensaios de expressão gênica por transcriptoma foram realizados em nosso laboratório (dados ainda não publicados), com o objetivo de analisar genes diferencialmente expressos associados à quimiossensibilidade ao docetaxel em células MCF-7 transfectadas com o vetor de expressão para PAR-4 (MCF7pcPAR4) e o com vetor vazio (MCF7pcNEO) antes e após o tratamento com docetaxel. Para avaliar a interação entre os genes diferencialmente expressos foram geradas redes gênicas funcionais utilizando o programa IPA- Ingenuity®. Dentre as diversas redes gênicas geradas destacaram-se as que continham genes relacionados direta ou indiretamente com a via de sinalização WNT (Wingless-Type MMTV Integration 1). O presente estudo visa validar genes diferencialmente expressos identificados em células MCF-7 com diferenças de expressão de PAR-4 antes e após a exposição de docetaxel. Através da anotação manual dos genes mais diferencialmente expressos, foram selecionados os genes EGR1, XAF1, TARP e WNT5A para validação por PCR em Tempo Real (qRT-PCR). A plataforma Human WNT Signaling Pathway RT2 Profiler(TM) PCR Array (PCR Array) foi utilizada para avaliar o efeito da overexpressão de PAR-4 e do tratamento de docetaxel na expressão de genes das vias canônica e não canônica do WNT. A expressão positiva do gene WNT5A nas células MCF7pcPAR4 em relação a MCF7pcNEO foi confirmada por qRT-PCR na ausença e presença do tratamento com docetaxel. O gene EGR1 apresentou regulação positiva significativa na técnica de qRT-PCR na ausência de tratamento, porém não apresenta o mesmo perfil de expressão observado no ensaio de transcriptoma. O gene XAF1 apresentou regulação negativa nas células MCF7pcPAR4 quando comparadas com as células MCF7pcNEO na ausência e presença de docetaxel, com tendência a validação na ausência de tratamento e de não validação na presença de docetaxel. Foi observado o aumento significativo da expressão de TARP nas células MCF7pcPAR4 por qRT-PCR na ausência e presença de docetaxel, porém esses achados não confirmam os resultados obtidos no transcriptoma. Em nossos dados de PCR Array na comparação MCF7pcPAR4 vs MCF7pcNEO antes do tratamento, encontramos diferença de expressão significativa (p < 0,005) em 9 genes. Sendo que, os genes CDKN2A, EGR1, FGF7, IL6 e TWIST apresentaram expressão positiva e os genes NTRK2, SOX2, SOX9 e WISP1 tiveram expressão negativa. Na comparação na presença de docetaxel observamos que os genes CACNAD2A3, GDF5, IL6, FGF7, LEF1 e TWIST apresentaram regulação positiva e FST apresentou regulação negativa com significância estatística (p < 0,005). Dos 84 genes da plataforma PCR array foram observados 21 e 14 genes comuns entre ambas às técnicas na ausência e presença de docetaxel, respectivamente. Na ausência de docetaxel 16 genes apresentaram o mesmo perfil de expressão, dentre estes a regulação positiva de GJA1, IGF1, IGF2, LEF1, MMP2, PDGFRA, PTGS2 e TWIST, associadas á regulação negativa de CDH1, JAG1, NTRK2 sugerem ativação da via WNT/?-catenina. Enquanto, a expressão de DAB2, WNT5A, FZD7 e RUNX2 indica inativação dessa via. Na presença do tratamento 6 genes apresentaram o mesmo perfil de expressão. Dentre estes, a regulação positiva de CTGF, DAB2 e EGR1 sugerem inativação da via WNT/beta-catenina. Por outro lado, a expressão positiva de FGF20, LEF1 e PDGFRA sugerem que via WNT/beta-catenina estaria ativa. Neste estudo, podemos mostrar que PAR-4 modula genes da via de sinalização WNT. Porém, mais experimentos serão necessários para verificar quais mecanismos estão envolvidos e de que forma isso reflete na quimiossensibilidade a drogasPAWR (Prostate Apoptosis Response-4) also known as PAR-4 is a pro-apoptotic gene identified in prostate cancer cells when exposed to apoptotic stimuli. PAR-4 expression can increase sensitivity of cells to apoptosis, including breast cancer cells. Our laboratory performed transcriptome profiling (unpublished data), with the aim of analyzing differentially expressed genes associated with chemosensitivity to docetaxel in transfected MCF-7 cells with PAR-4 expression plasmid (MCF7pcPAR4) and with empty vector (MCF7pcNEO) before and after treatment with docetaxel. To assess the interaction between the differentially expressed genes functional gene networks were generated using the IPA Ingenuity® software. Networks generated containing genes directly or indirectly related with the WNT signaling pathway (Wingless-Type MMTV Integration 1) were highlighted. The present study aims to validate the differentially expressed genes identified in MCF-7 cells with different PAR-4 expression before and after exposure of docetaxel. By manual annotation of the genes most differentially expressed, the genes EGR1, XAF1, TARP and WNT5A were selected to be validated by quantitative real time PCR (qRT-PCR). The platform WNT Signaling Pathway Human RT2 Profiler (TM) PCR Array (Array PCR) was used to evaluate the effect of PAR-4 overexpression and docetaxel treatment in gene expression of canonical and noncanonical WNT pathways. The positive expression of WNT5A in MCF7pcPAR4 cells relative to MCF7pcNEO was confirmed by qRT-PCR in the presence and absence of docetaxel. The EGR1 gene showed significant upregulation in the qRT-PCR in the absence of treatment, but showed a different expression profile of the one observed in the transcriptome assay. The XAF1 showed a negative regulation in MCF7pcPAR4 cells when compared with MCF7pcNEO cells in the absence and presence of docetaxel, showing a similar trend in the absence of treatment but opposed trend in the presence of docetaxel. It was observed a significant increase in TARP expression in MCF7pcPAR4 cells by qRT-PCR in the absence and presence of docetaxel, but these findings do not confirm the results of the transcriptome. PCR Array data of MCF7pcPAR4 vs MCF7pcNEO comparison before treatment, showed a significant expression difference in nine genes (p < 0.005). The genes CDKN2A, EGR1, FGF7, IL6 and TWIST showed positive expression and the genes NTRK2, SOX2, SOX9 and WISP1 had negative expression. In the presence of docetaxel it was observed that the genes CACNAD2A3, GDF5, IL6, FGF7, LEF1 and TWIST showed upregulation and FST downregulation with statistical significance (p < 0.005). From 84 genes of the platform PCR array we observed 21 and 14 common genes between both techniques in the absence and presence docetaxel, respectively. In the absence of docetaxel 16 genes showed similar expression profile, among them the upregulation of GJA1, IGF1, IGF2, LEF1, MMP2, PDGFRA, PTGS2 and TWIST, together with downregulation of CDH1, JAG1, NTRK2 suggest activation of the WNT/beta-catenin pathway. While the expression of DAB2, WNT5A, FZD7 and RUNX2 indicates inactivation of this pathway. In the presence of treatment six genes showed the same expression profile. Among these, the upregulation of CTGF, DAB2 EGR1 suggest the inactivation of Wnt/beta-catenin pathway. On the other hand, positive expression of FGF20, LEF1 and PDGFRA suggests that Wnt/beta-catenin would be active. In this study, we show that PAR-4 modulates genes of the WNT signaling pathway. However, more experiments are needed to clarify the role of WNT canonical and non-canonical pathways and how this reflects on drug chemosensitivity
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Lima, Lorena de Oliveira e. "Estudo da Beta-catenina em tumores adrenocorticais humanos." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/5/5135/tde-14082014-151107/.
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Introdução: A incidência de tumores adrenocorticais em crianças é particularmente elevada nas regiões sudeste e sul do Brasil, correlacionandose com a ocorrência da mutação germinativa p.R337H do supressor tumoral p53, entretanto, o carcinoma adrenocortical é uma neoplasia endócrina maligna rara em todo o mundo com uma incidência aproximada de 0,5 - 2 casos por milhão por ano. Esta condição é uma doença heterogênea, apresentando frequentemente comportamento clínico agressivo e letal. A cascata de sinalização Wnt é uma via importante de transdução de sinal em cânceres humanos e tem sido implicada na tumorigênese adrenocortical. A atividade desta via de sinalização é dependente da quantidade de beta-catenina citoplasmática e nuclear. Mutações ativadoras no gene da beta-catenina (CTNNB1) foram relatadas em diversas neoplasias humanas. Estudos demonstraram que mutações no gene CTNNB1 são os defeitos genéticos mais frequentemente encontrados em adenomas e em carcinomas adrenocorticais. O estudo destas mutações demonstrou que as alterações no gene CTNNB1 localizam-se principalmente exon 3, que codifica a porção amino terminal da beta- catenina. Objetivos: determinar a ocorrência e a frequência das mutações somáticas no exon 3 do gene CTNNB1. Adicionalmente, determinar a imunorreatividade de beta-catenina e de p53 em tumores adrenocorticais benignos e malignos de crianças e adultos. Correlacionar os resultados da análise de mutações gênicas e os dados de imunorreatividade com as características hormonais, a mutação p.R337H do p53, o diagnóstico histológico e a evolução dos tumores adrenocorticais de crianças e adultos. Métodos: Neste estudo, a análise de imunohistoquímica para beta-catenina e p53 foi realizada em 103 tumores adrenocorticais benignos e malignos (40 crianças e 63 adultos), estando as amostras histológicas alocadas em micromatriz tecidual (TMA). A pesquisa de mutações no exon 3 do gene CTNNB1 foi determinada por seqüenciamento automático em 64 tumores adrenocorticais. Resultados: a imunorreatividade para beta-catenina em citoplasma e/ou núcleo foi evidenciada de maneira similar nos tumores adrenocorticais benignos e malignos de crianças e de adultos (15% e 23,8%, respectivamente). O percentual das células neoplásicas imunorreativas para beta-catenina em citoplasma e/ou núcleo não foi significativamente diferente entre os tumores clinicamente benignos e malignos pediátricos (15,6% vs. 12,5%, respectivamente; p=0,93) e entre adenomas e carcinomas adrenocorticais de adultos (28,5% vs. 17,8%, respectivamente; p=0,38). A síndrome endócrina causada pelo perfil de secreção hormonal foi similar entre os tumores adrenocorticais com presença ou ausência de acúmulo citoplasmático e/ou nuclear de beta-catenina em crianças e adultos. A associação entre acúmulo anormal de beta-catenina e diminuição de sobrevida foi avaliada nos pacientes adultos portadores de carcinomas adrenocorticais isoladamente (n=25), sendo observada na curva de Kaplan- Meier uma tendência de significância (log-rank p=0,07). A análise do gene CTNNB1 revelou mutações somáticas em heterozigose em 10 tumores adrenocorticais (4 crianças e 6 adultos). As mutações encontradas no gene CTNNB1 foram, sobretudo do tipo missense (p.Ser45Pro, p.Ser45Phe, p.Asp32Asn, p.Pro44Ala_Ser45Pro; p.His36Gln_Ser37Lys). Outras mutações encontradas compreenderam: a inserção de um único nucleotídeo (p.E9GfsX14), dando origem a uma desvio de leitura do exon 3; além da deleção dos três nucleotídeos do códon 45 (p.Ser45del). Todos os tumores com mutações somáticas no gene CTNNB1 mostraram acúmulo anormal para ?-catenina, com exceção de um caso. A presença de alterações no gene CTNNB1 não se associou ao tamanho do tumor (Teste de Mann-Whitney: p=0,75), desfecho desfavorável tanto no grupo pediátrico (log-rank p=0,29) como no grupo de pacientes adultos (log-rank p=0,77). Todos os pacientes portadores da mutação germinativa do gene TP53 apresentaram imunorreatividade nuclear de p53 nas células tumorais. Não foi encontrada correlação entre a presença de acúmulo anormal de beta-catenina e imunorreatividade nuclear de p53, considerando os grupos de crianças e de adultos portadores de tumores adrenocorticais. Adicionalmente, não foi observada correlação entre mutações no gene CTNNB1, bem como acúmulo anormal de beta-catenina, com a imunorreatividade nuclear de p53 no grupo de tumores adrenocorticais de pacientes adultos, porém, interessantemente, avaliando isoladamente o grupo de tumores adrenocorticais pediátricos, foi observada relação entre a presença de mutações no gene CTNNB1 e a presença de acúmulo nuclear de p53 (X2: p=0,009). Conclusões: Estes dados confirmam a participação da via Wnt na tumorigênese adrenocortical de crianças e de adultos, que apresenta uma prevalência de ativação semelhante entre crianças e adultos. O acúmulo citoplasmático e/ou nuclear de beta-catenina provavelmente é um marcador biológico de mau prognóstico do carcinoma de adrenocortical de adultos. Adicionalmente, observamos evidências de uma correlação positiva entre mutações no gene CTNNB1 e acúmulo nuclear de p53 em tumores adrenocorticais pediátricos, confirmando uma possível relação destas duas vias na tumorigênese do córtex da glândula suprarrenalIntroduction: The incidence of adrenocortical tumors in children is particularly high in the southeastern and southern regions of Brazil, correlating with the occurrence of p.R337H p53 tumor suppressor germline mutation. However, adrenocortical carcinoma is a worldwide rare endocrine malignancy with an approximate incidence of 0.5 to 2 cases per million per year. This condition is a heterogeneous disease and is often lethal. The Wnt signaling pathway is an important signal transduction pathway in human cancers and has been implicated in adrenocortical tumorigenesis. The activity of this signaling pathway is dependent on the amount of nuclear and cytoplasmic beta-catenin. Activating mutations of ?-catenin (CTNNB1) gene have been reported in several human malignancies. Studies have shown that CTNNB1 mutations are the most common genetic defect found in adrenocortical adenomas and carcinomas. The study of these mutations demonstrated that the changes in CTNNB1 gene are mainly located in exon 3, which encodes the amino terminal portion of the beta- catenin. Objectives: to determine the occurrence and frequency of CTNNB1 somatic mutations and the abnormal beta-catenin and p53 accumulation in benign and malignant adrenocortical tumors in both children and adults. We also evaluated the correlation of the gene mutations analysis and immunohistochemistry data with the hormonal characteristics, the p.R337H germline mutation, the histological diagnosis and the prognosis of adrenocortical tumors in children and adults. Methods: In this study, immunohistochemistry for beta-catenin and p53 was performed in 103 benign and malignant (40 children and 63 adults) adrenocortical tumors. The histological samples were allocated in a tissue microarray (TMA). The study of the CTNNB1 gene was performed by direct sequencing of 64 adrenocortical tumors. Results: The beta-catenin abnormal accumulation was similar in benign and malignant adrenocortical tumors of children and adults (15 % and 23.8 %, respectively). The percentage of cells with beta-catenin abnormal accumulation was not significantly different between benign and malignant pediatric adrenocortical tumors (15.6% vs. 12.5 %, respectively; P=0.93) and between adrenocortical adenomas and carcinomas in adults (28.5% vs 17.8 %, respectively; p=0.38). The endocrine syndrome caused by hormonal tumor secretion was similar in patients with and without beta-catenin abnormal accumulation both in pediatric and adult patients. The association between beta-catenin abnormal accumulation and decreased survival was evaluated in adult patients with adrenocortical carcinomas (n=25) and a trend toward significance was observed (log-rank p=0,07). The analysis of the CTNNB1 gene revealed heterozygous somatic mutations in 10 adrenocortical tumors (6 adults and 4 children). The mutations found in CTNNB1 gene were mainly missense (p.Ser45Pro, p.Ser45Phe, p.Asp32Asn, p.Pro44Ala_Ser45Pro; p.His36Gln_Ser37Lys). Other mutations found included: a single nucleotide insertion (p.E9GfsX14) and a deletion within codon 45 of exon 3 of CTNNB1 gene, (p.Ser45del). All tumors with somatic mutations in the CTNNB1 gene showed abnormal beta -catenin accumulation, except for one case. The mutations in CTNNB1 gene was not associated with tumor size (Mann - Whitney: p=0.75), unfavorable outcome in both pediatric (log -rank p=0.29) and adult group of patients (log-rank p=0.77). All patients with TP53 germline mutation showed p53 nuclear accumulation in the tumor cells. No correlation was found between the presence of beta-catenin abnormal accumulation and p53 nuclear accumulation in adrenocortical tumor cells of children and adults. In addition, no correlation was observed between CTNNB1 mutations, as well as beta-catenin abnormal accumulation, with p53 nuclear accumulation in adults adrenocortical tumors. Interestingly, the evaluation of pediatric adrenocortical tumors revealed a relationship between the occurrence of CTNNB1 mutations and the presence of p53 nuclear accumulation (X2: p=0.009). Conclusions: These data confirm the involvement of the Wnt pathway in adrenocortical tumorigenesis of children and adults, which has a prevalence similar activation between children and adults. We observed that abnormal beta-catenin accumulation in adults adrenocortical carcinoma is probably associated with a dismal prognosis. Additionally, we found evidence of a positive relationship between CTNNB1 mutations and p53 nuclear accumulation in pediatric adrenocortical tumors, confirming a possible connection of these two pathways in the pediatric adrenocortical tumorigenesis
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Duflot, Nicolas. "Contribution à l'analyse des facteurs déterminant les fibroses graves du foie (bilharziose) et de la peau (tissus chéloïdes)." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0773.
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Les fibroses anormales sont responsables de plus de 40% des décès pour raison médicale ; elles se développent suite à une inflammation chronique. Les fibroses hépatiques causées par les schistosomes et par le virus HCV sont en grande partie déterminées par la génétique du malade. Notre thèse a consisté à poursuivre le travail de caractérisation du déterminisme génétique des fibroses hépatiques et cutanées.La première partie de notre thèse, est l’étude informatique et statistique des données de génotypage GWAS de Brésiliens qui présentent une fibrose hépatique bilharzienne grave sur plus de 2,5 millions de SNPs. 180 SNPs qui montraient une association suggestive avec les fibroses graves ont été sélectionnés, dont certains affectent les gènes des voies Wnt. Ces SNPs ont été testés sur une cohorte de 460 pêcheurs ougandais exposés à S.mansoni et nous avons confirmé l’association avec la fibrose de 4 SNPs.La deuxième partie de notre thèse est l’analyse transcriptômique (RNA-Seq) des mécanismes responsables des fibroses anormales de la peau de sujets affectés par des fibroses chéloïdes de 20 tissus chéloïdes, 7 tissus sains et 7 tissus affectés par des cicatrices hypertrophiques. Cette analyse montre que le développement des chéloïdes est la conséquence d’une stimulation anormale des voies de la cicatrisation en partie due à l’activation de la voie Wnt βcatenin et Wnt PCP. Pour conforter cette proposition, nous avons effectué une analyse génétique de la voie Wnt dans deux cohortes indépendantes. L’analyse statistique montre que des SNPs dans 6 gènes de la voie Wnt βcatenin contribuent au développement des fibroses chéloïdesAbnormal fibrosis is responsible for more than 40% of medical deaths. They develop as a result of chronicinflammation. Hepatic fibroses caused by schistosomes andHCV virus are largely determined by the genetic background of the patient. Our thesis consisted of continuing thework of characterizing the genetic determinism of liver and skin fibrosis.The first part of our thesis is the computer and statistical study of GWAS genotyping data of Brazilians whohave severe bilharzeal liver fibrosis on more than 2.5 million SNPs. 180 SNPs that showed suggestive associationwith severe fibrosis were selected, some of which affect the Wnt pathway. These SNPs were then tested on a cohortof 460 Ugandan fishers exposed to S.mansoni and the results confirmed the association of 4 SNPs with fibrosis.The second part of our thesis is the genomic analysis (transcriptome and genetics) of the mechanismsresponsible for the abnormal skin fibrosis with subjects affected by keloid scars. We performed an analysis of genes(RNASeq) expressed differently between 20 keloids, 7 healthy tissues and 7 tissues affected by hypertrophic scars.This analysis shows that the development of keloids is the consequence of an abnormal stimulation of cicatrizationpathways with strong activation of the Wnt βcatenin and Wnt PCP pathway. To support this proposal, we performeda genetic analysis of the Wnt pathway in two independant cohorts.The statistical analysis of the results shows that polymorphisms in 6 genes of the Wnt βcatenin pathway contributeto the development of keloid fibrosis
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Barrott, Jared James. "Wnt5a Signaling Independently of the Planar Cell Polarity Pathway Resulting in Convergent Extension and Neural Tube Closure During Vertebrate Development." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2612.pdf.
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Nimmrich, Inko. "Tumorspezifisch exprimierte und Wnt-1-induzierte Gene." [S.l.] : [s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=959806369.
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Chandra, Manasa Tumulak James. "Attempted cloning of a Wnt gene from Botrylloides violaceus /." Click here to view, 2009. http://digitalcommons.calpoly.edu/biosp/3.
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Thesis (B.S.)--California Polytechnic State University, 2009.Project advisor: Elena Keeling. Title from PDF title page; viewed on Jan. 20, 2010. Includes bibliographical references. Also available on microfiche.
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Guo, Jiami. "The requirement of Smad4 in Mouse Early Embryonic Development." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1343160155.
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Chamorro, Mario Narciso. "Characterization of different aspects of Wnt signaling : in human and mouse tumors /." Access full-text from WCMC, 2009. http://proquest.umi.com/pqdweb?did=1619205751&sid=2&Fmt=2&clientId=8424&RQT=309&VName=PQD.
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