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Träfflista för sökning "WFRF:(Lejonklou Margareta Halin) srt2:(2005-2009)"

Sökning: WFRF:(Lejonklou Margareta Halin) > (2005-2009)

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1.
  • Ekeblad, Sara, et al. (författare)
  • Co-expression of ghrelin and its receptor in pancreatic endocrine tumours
  • 2007
  • Ingår i: Clinical Endocrinology. - : Wiley. - 0300-0664 .- 1365-2265. ; 66:1, s. 115-122
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective Expression of ghrelin has been reported in pancreatic endocrine tumours, but data on ghrelin receptor protein expression are lacking. The aim of this study was to examine the ghrelin receptor, as well as ghrelin, in a selected series of these tumours, including multiple endocrine neoplasia 1 (MEN1) associated tumours, and to correlate data with clinical features including body mass index.Design Immunohistochemical detection of ghrelin and its receptor was performed on frozen tissue from 31 tumours: 9 MEN1 and 22 sporadic. Twenty tumours were analysed by quantitative PCR. Plasma ghrelin was assessed in 26 patients.Results Twenty-one (68%) of 31 tumours showed immunoreactivity for ghrelin (8/9 MEN1) and 19/20 expressed ghrelin mRNA. Ghrelin receptor protein was detected in 21/30 (70%) tumours (4/8 MEN1), and mRNA was detected in all analysed tumours. Insulinomas had significantly higher levels of receptor mRNA than other tumours. Five patients had elevated plasma ghrelin (> 2 SD above the control group mean). No significant difference in mean plasma ghrelin levels was found between patients (908 ± 569 ng/l) and controls (952 ± 164 ng/l). Mean BMI was 24·3 kg/m2. There was no association between ghrelin or receptor expression and survival.Conclusions We report the first immunohistochemical data on expression of the ghrelin receptor in pancreatic endocrine tumours: 70% of tumours in our material. Concomitant ghrelin and receptor expression was seen in 50% of tumours, indicating an autocrine loop. Ghrelin was expressed in 68% of tumours (8/9 MEN1). Despite frequent ghrelin expression, elevated circulating ghrelin is rare in these patients.
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2.
  • Ekeblad, Sara, et al. (författare)
  • Gastrointestinal stromal tumors express the orexigen ghrelin
  • 2006
  • Ingår i: Endocrine-related cancer. - : Bioscientifica. - 1351-0088 .- 1479-6821. ; 13:3, s. 963-70
  • Tidskriftsartikel (refereegranskat)abstract
    • Expression of the neuroendocrine marker synaptic vesicle protein 2 (SV2) has been reported in a few cases of gastrointestinal stromal tumors (GISTs). The goal of the present study was to assess the relevance of this finding and identify a possible hormone production in these tumors. We chose to study the orexigen ghrelin and its receptor, since these patients are seldom cachexic, even in advanced disease stages. We investigated ghrelin expression by means of immunohistochemistry on frozen or paraffin-embedded sections from 22 GISTs from a well-characterized patient material. Expression of the growth hormone secretagogue receptor, the ghrelin receptor, was investigated in a subset of lesions. In six tumors, mRNA levels of ghrelin, the ghrelin receptor, and SV2 were analyzed by real-time quantitative PCR. Totally 17 out of 22 tumors showed immunoreactivity for ghrelin. Five out of ten tumors were immunoreactive for the ghrelin receptor, and all of these co-expressed ghrelin. All tumors expressed ghrelin, ghrelin receptor, and SV2 mRNA. GISTs frequently express SV2, ghrelin, and its receptor, indicating the presence of autocrine/paracrine loops.
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3.
  • Johansson, T, et al. (författare)
  • Lack of Nuclear Expression of Hairy and Enhancer of Split-1 (HES1) in Pancreatic Endocrine Tumors
  • 2008
  • Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 0018-5043 .- 1439-4286. ; 40:5, s. 354-359
  • Tidskriftsartikel (refereegranskat)abstract
    • The Notch signaling cascade plays a vital role in the proliferation and differentiation of cells during pancreatic development. Cell line experiments have suggested the involvement of Notch signaling in pancreatic endocrine tumorigenesis. We investigated the expression of NOTCH1, HES1, HEY1 and ASCL1 in pancreatic endocrine tumors and compared the data to tumor phenotype including hormone production, heredity, and WHO classification. Real-time quantitative PCR and immunohistochemistry were performed on samples of 26 pancreatic endocrine tumors. For comparison, 10 specimens of macroscopically normal pancreas were analyzed using immunohistochemistry. The subcellular localization of proteins was determined. Neither hormone production, nor heredity, or WHO classification was found to be associated with the expression of these proteins. There were discrepancies between mRNA and protein expression levels. All tumors displayed ASCL1 immunoreactivity. HES1 immunoreactivity was lacking altogether in 46% of the tumors, and in the remaining lesions its expression was weak and confined to the cytoplasm. In the nontumorous pancreatic endocrine cells, weak nuclear expression of HES1 as well as of HEY1 and NOTCH1 was observed. There was a significant positive correlation between NOTCH1 and HES1 mRNA levels, but no indication that HES1 was inhibiting ASCL1 transcription was found. No nuclear expression of HES1 was found in the tumors. This lack of nuclear expression of HES1 may contribute to the abundance of ASCL1 and to tumorigenesis in the endocrine pancreas.
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4.
  • Lejonklou, Margareta Halin, et al. (författare)
  • Neurogenin 3 and neurogenic differentiation 1 are retained in the cytoplasm of multiple endocrine neoplasia type 1 islet and pancreatic endocrine tumor cells
  • 2009
  • Ingår i: Pancreas. - 0885-3177 .- 1536-4828. ; 38:3, s. 259-266
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVES:To investigate if transcription factors involved in pancreatic differentiation and regeneration are present in pancreatic endocrine tumors and if they are differentially expressed in normal pancreas compared with multiple endocrine neoplasia type 1 (MEN1) nontumorous pancreas.METHODS:The expression of neurogenin 3 (NEUROG3), neurogenic differentiation 1 (NEUROD1), POU class 3 homeobox 4 (POU3F4), pancreatic duodenal homeobox factor 1 (PDX1), ribosomal protein L10 (RPL10), delta-like 1 homolog (Drosophila; DLK1), and menin was analyzed by immunohistochemistry in normal pancreas and pancreatic endocrine tumors from 6 patients with MEN1 and 16 patients with sporadic tumors, as well as pancreatic specimens from Men1 heterozygous and wild type mice. Quantitative polymerase chain reaction was performed in a subset of human tumors.RESULTS:Tumors and MEN1 nontumorous endocrine cells showed a prominent cytoplasmatic NEUROG3 and NEUROD1 expression. These factors were significantly more expressed in the cytoplasm of Men1 heterozygous mouse islet cells compared with wild type islets; the latter showed an exclusively nuclear reactivity. The degree of Pou3f4, Rpl10, and Dlk1 immunoreactivities differed significantly between islets of heterozygous and wild type mice. The expressions of RPL10 and NEUROD1 were prominent in the MEN1 human and heterozygous mouse exocrine pancreas. Insulinomas had significantly higher PDX1 and DLK1 messenger RNA levels compared with other tumor types.CONCLUSIONS: Transcription factors involved in pancreatic development show altered expression and subcellular localization in MEN1 nontumorous pancreas and pancreatic endocrine tumors.
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5.
  • Stålberg, Peter, et al. (författare)
  • Recognizing genes differentially regulated in vitro by the multiple endocrine neoplasia type 1 (MEN1) gene, using RNA interference and oligonucleotide microarrays
  • 2006
  • Ingår i: Surgery. - : Elsevier BV. - 0039-6060 .- 1532-7361. ; 140:6, s. 921-931
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Data on downstream effects of MEN1 gene inactivation is scarce. In an effort to identify genes regulated by MEN1, we designed a silencing experiment in a human endocrine pancreatic tumor cell line (BON1). Methods: By using RNA interference, MEN1 mRNA expression was knocked-down by >85%. Gene expression was assessed by oligonucleotide microarrays and compared to expression in nonsilenced controls. We also investigated if genes were differentially expressed in 6 malignant endocrine pancreatic tumors (EPTs) with homozygous MEN1 inactivation compared to 2 without MEN1 gene alterations. Results: Using a cut-off of ≥2 times, 66 genes were found to be upregulated, and 22 were downregulated in the MEN1-silenced clones. We corroborated the microarray findings by performing quantitative-PCR on the RNA from the silencing experiments for 7 of the 88 differentially regulated genes. Genes involved in endocrine cell fate determination, as well as genes known to be involved in NFkappaB, Notch, and Wnt signaling pathways, were among genes verified as differentially regulated in vitro. Conclusions: The demonstration of pathways affected by silencing of MEN1 in vitro provides novel insight into neoplastic processes of potential importance in vivo, which warrants further study.
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