Thesis (doctoral)--Lund, 1983.

Thesis (doctoral)--Lund University, 1998. / Added t.p. with thesis statement inserted.

Orientador: Patricia Pintor dos Reis / Abstract: Background: Genetic alterations were previously identified and associated with the development and progression of pancreatic carcinoma, however, identification of such alterations has not been currently used for the development of efficient treatment strategies. Therefore, the identification of other genetic and epigenetic changes, such as alterations in non-coding RNA molecules is urgently needed for the development of novel therapies. Recent studies have suggested that microRNAs (miRNAs) are frequently deregulated in several carcinomas and may contribute in the several steps of development and tumor progression. Global miRNA profiling analysis in pancreatic carcinoma and the identification of miRNA target genes may lead to new avenues for the identification of clinically applicable biomarkers. Objectives: To identify global microRNA (miRNA) expression profiles and miRNA predicted target genes in pancreatic carcinoma. Patients and Methods: 30 formalin fixed, paraffin embedded (FFPE) pancreatic carcinoma tissue samples were used, including 24 pancreatic ductal adenocarcinoma (PDAC) and 6 adenocarcinomas of Vater papilla (AMP) and their paired histologically adjacent normal tissues. Global miRNA expression profiles were determined using the TaqMan Array Human MicroRNA Cards (TLDA) (card A, v3.0) (Life Technologies) platform. Data analysis used the ExpressionSuite Software v1.0.3. Statistical analysis was performed to correlate miRNA expression with relevant clinical data, usin... (Complete abstract click electronic access below) / Resumo: Introdução: Alterações genéticas foram previamente identificadas e associadas ao desenvolvimento e progressão dos carcinomas pancreáticos, entretanto, o conhecimento dessas alterações não resultou, até o momento, no desenvolvimento de tratamentos eficazes para os pacientes com essas neoplasias. Sendo assim, torna-se necessária e justificada a identificação de outras alterações, tais como alterações em moléculas reguladoras da expressão gênica, as quais têm o potencial de levar ao delineamento de novas terapias. Estudos recentes têm sugerido que os microRNAs (miRNAs) estão frequentemente desregulados em diversos carcinomas, e podem contribuir em várias etapas do desenvolvimento e progressão tumoral. A análise do perfil de expressão de miRNAs em carcinomas de pâncreas e genes regulados por estes miRNAs, deve fornecer novas direções para a identificação de biomarcadores que possam ser úteis na prática clínica. Objetivos: Identificar perfis globais de expressão de microRNAs (miRNAs) e potenciais genes-alvo regulados por miRNAs em carcinomas de pâncreas. Pacientes e Métodos: Foram incluídas 30 amostras de tecido, fixadas em formalina e emblocadas em parafina (FFPE) de carcinoma de pâncreas, sendo 24 adenocarcinomas de ductos pancreáticos (PDAC) e 6 adenocarcinomas de papila de Vater (AMP) e os tecidos histologicamente normais, adjacentes ao tumor, correspondentes a cada caso. O perfil de expressão de miRNAs das amostras tumorais foi determinado utilizando o ensaio TaqMan Array Hum... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

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The work presented in this thesis is a study of human pancreas development. The principle goal of this work is to provide information that can be used in the development of treatments for Type 1 Diabetes and in pancreas regeneration methodologies. The transcription factor (TF) sex determining region Y homeobox gene 9 (SOX9) has been identified as a key factor in human pancreas development but its role has not been well characterized. The expression of SOX9 during early pancreas development was analyzed by immunostaining of fixed embryonic and fetal sections in the context of other developmentally important TFs. Modulators of SOX9 function, downstream targets and upstream regulatory pathways were investigated in human cell lines using coimmunoprecipitation, small interfering RNA (siRNA) knockdown, quantitative polymerase chain reaction (qPCR), luciferase assays and small molecule signaling pathway inhibitors. SOX9 was expressed in epithelial progenitors from initial human pancreas specification, but became excluded from the periphery of the epithelium and developing islet cells as differentiation proceeded. It was co-expressed with important endocrine and exocrine differentiation factors during the early stages of development. Some factors, such as Nirenberg and Kim 2, homeobox family member, drosophila, homolog of, 2 (NKX2.2) showed differing expression profile compared to murine development, while the widespread expression of endocrine factors before expression of the pro-endocrine gene neurogenin 3 (NGN3) suggested that these factors play an important role in initiating endocrine specification. Two transcription factors, GATA-binding protein 4 (GATA4) and neurogenic differentiation 1 (NEUROD1), were found to interact with SOX9 in potentially developmentally relevant complexes. This prompted the search for downstream targets of these transcriptional complexes by in silico analysis, which identified an array of novel potential downstream targets. Luciferase assay analysis of a subset of these genes showed SOX9 to activate a regulatory region of NGN3, and inhibit the regulatory regions of carboxy peptidase A6 (CPA6), v-ets avian erythroblastosis virus E26 oncogene homolog1 (ETS1) and SPONDIN1. An additional target of SOX9, osteopontin (OPN), was identified from a microarray of Sox9 knockout mouse pancreata. Investigation of SOX9 and OPN regulation by the Hedgehog signalling pathway (HH) identified both factors to be regulated by the pathway, suggesting SOX9 may act as a mediator of HH signalling. This is the first study to identify a range of SOX9 targets relevant to human pancreas development. While further characterization is required this work has provided essential clues to the function of SOX9, and provides a detailed framework of SOX9 expression and targets for future pancreatic studies to build upon.

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Context: Pseudocysts are a common complication of acute and chronic pancreatitis. These are usually located within the pancreas but they can occur at other sites as well, including the mediastinum, neck, pelvis and rarely in the liver as in our case. The diagnosis of intrahepatic pancreatic pseudocyst relies on the demonstration of a high amylase level in the sampled cystic fluid in the absence of infection or neoplasm. Case report: A 60-year-old man with a history of chronic pancreatitis presents with a clinical and laboratory picture suggestive of acute exacerbation of his pancreatitis. A computed tomogram (CT) scan of the abdomen revealed a pancreatic pseudocyst and a cystic lesion involving both lobes of the liver. CT diagnostic aspiration of the intrahepatic cyst revealed high amylase level (greater than 20,000 U/L). The cyst was treated with percutaneous drainage with complete resolution of the cyst. Conclusion: In the setting of pancreatitis, intrahepatic pancreatic pseudocyst should be considered in the differential diagnosis of cystic lesion of the liver.

Cancer is associated with many molecular aberrations that support the malignant phenotype. In that regard, aberrant activation of epidermal growth factor receptor (EGFR), Src, and signal transducer and activator of transcription 3 (Stat3) occur concurrently in pancreatic cancer and are implicated in the disease phenotype. Notwithstanding, increasing evidence indicates that therapies that target only EGFR or Src are rather ineffective in modulating the cancer phenotype. The poor therapeutic outcome of the monotherapies targeting EGFR or Src may in part be due to the increased incidence of signaling cross-talks among aberrant signaling pathways in cancer. Molecular details of the signaling integration between EGFR, Src and Stat3, however, are lacking. Understanding how the aberrant EGFR, Src and Stat3 pathways are integrated in pancreatic cancer would facilitate the design of effective multipletargeted, clinically feasible therapeutic modalities. Our study shows that in pancreatic cancer cell lines, aberrant Src activity promotes abnormal EGFR activation through the phosphorylation of the EGFR motifs, Tyr845, Tyr1068 and Tyr1086. Furthermore, aberrantly-active EGFR and Src together induce constitutive activation of Stat3 in pancreatic cancer cells. Evidence further shows that EGFR, Src and Stat3 physically associated into a heteromeric complex. Significantly, the EGFR, Src and Stat3 heteromeric complex is detectable in the nucleus and functions as a transcriptionallyactive complex to induce the c-Myc gene. Of therapeutic significance, the concurrent inhibition of Stat3 and EGFR or Src promoted greater viability loss and apoptosis of pancreatic cancer cells in vitro, and induced stronger tumor growth inhibition in xenografts of human pancreatic cancer. Altogether, our studies suggest that the iii heteromeric EGFR, Src, and Stat3 complex may serve as an additional novel mechanism of support of the pancreatic cancer phenotype. Furthermore, our studies provide evidence that the concurrent targeting of Stat3 and EGFR or Stat3 and Src could be a more effective therapeutic approach for human pancreatic cancer.

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