Project description:Members of the Nuclear mRNA Export Factor (NXF) family are implicated in nuclear export and/or cytoplasmic transport of mRNAs in eukaryotic cells. We previously proposed NXF5 to be involved in cognitive development and aimed to study its functional role further using a mouse model. The syntenic region of the human Xcen-GLA-NXF5-NXF2-NXF3-BEX4-Xqter in the mouse is Xcen-Gla-Nxf2-Nxf7-Nxf3-Bex4-Xqter strongly indicating that mouse Nxf2 is the homolog of human NXF5. However, our functional analyses demonstrated that mouse Nxf7 is actually the functional homolog of NXF5. Both orthologs are expressed in brain, although at low levels, show predominant cytoplasmic localization, and present a granular staining in neuronal dendrites, all indicative for a role in cytoplasmic mRNA transport or metabolism. The mouse and human Nxf2/NXF2 proteins on the other hand, show highest expression in testis, and mostly nuclear staining with incorporation in the nuclear membrane, suggesting a predominant role in nuclear mRNA export. Based on these findings we generated an Nxf7 knockout mouse, which was viable and fertile and no gross anatomical changes or morphological brain abnormalities were detected. Detailed behavioral analysis demonstrated that Nxf7 KO mice displayed a deficit in hippocampus-dependent spatial learning and memory. At the cellular level, this was accompanied by impaired hippocampal long-term potentiation, but normal long-term depression, suggesting a severe functional imbalance in NMDA-dependent synaptic plasticity. In conclusion, the present findings indicate that NXF5, and its murine ortholog Nxf7, play a crucial role in neurocognitive (memory) functions, and explain why its deletion leads to intellectual disability. Two male wild type (WT1 and WT2) and two Nxf7 knockout (KO1 and KO2) mice were used in each hybridization experiment (hippocampus or cortex). A loop-design hybridization scheme (WT1/KO1, KO1/WT2, WT2/KO2 and KO2/WT1) was performed for each experiment so as to have each sample labeled once with Cy5 and once with Cy3, and hybridised to both samples of the other genotype (WT or KO). Hybridization was done on Agilent Mouse Whole Genome arrays according to the manufacturerM-bM-^@M-^Ys procedures.

Project description:NIPP1, an established interactor of protein phosphatase 1 (PP1), is implicated in PRC2-mediated regulation of gene expression. Here, we explore whether PP1 associated with NIPP1 is involved in NIPP1-mediated regulation of genes. Therefore, we generated Hela Tet-off (HTO) cell lines that stably and inducibly express a Flag-tagged version of wild-type NIPP1 (HTO-NIPP1wt) or mutant NIPP1 (HTO_NIPP1m). The latter mutant lacks the major PP1 binding site by two point mutations in the RVXF-motif, an established PP1 - binding motif. All cell lines were derived from the same parental HeLa Tet-Off (HTO-PT) cell line which expresses only tTA transactivator and is used as a control. The Flag fusions were only expressed in the absence of doxycyline and at levels that were up to twofold higher than that of endogenous NIPP1. We performed a gene expression profiling of the HTO cell lines, using Whole Human Genome Oligo microarrays from Agilent. A Paired SAM analysis identified 1365 genes with an altered expression (P < 0.01) between the Flag-NIPP1 and parental cell lines. Importantly, only 185 genes were differentially expressed (P<0.01) between the Flag-NIPP1m and parental cell lines. Even more strikingly, only 5% of the genes that were affected by the expression of Flag-NIPP1 also showed a significantly different expression in the Flag-NIPP1m cells. A similar small overlap was noted when the analysis was restricted to the 50 genes that were most upregulated or downregulated by the expression of Flag-NIPP1. Finally, scatter plot analysis revealed no significant correlation between the genes that were affected by the expression of Flag-NIPP1 or Flag-NIPP1m. Collectively, these data demonstrate that a moderate increase in the concentration of NIPP1 affects the expression of numerous genes by a mechanism that depends on associated PP1. In total 12 samples were processed. Three different cell lines were analysed: HTO_parental, HTO_NIPP1wt and HTO_NIPP1m. For each cell line 4 replicates were obtained. The HTO_parental cell line is the control cell line. For the HTO_NIPP1wt the 4 replicates were obtained from two replicates of two different transgenic cell lines expressing FlagNIPP1wt (cell line wt n°1 and 2). Each cell line derived from the same parental control cell line.

Project description:Pituitary adenomas cause significant endocrine and mass-related morbidity. Not much is known about mechanisms underlying pituitary tumor pathogenesis.We searched for a side population (SP) in pituitary tumor, representing cells with high efflux capacity and potentially enriching for cancer/tumor stem cells (CSC/TSC). Human pituitary adenomas contain a SP irrespective of hormonal phenotype. This adenoma SP, as well as the further purified SP (pSP) depleted from endothelial and immune cells, enriches for cells that express ‘tumor stemness’ markers and signaling pathways, including epithelial-mesenchymal transition (EMT)-linked factors. The adenomas were found to contain self-renewing sphere-forming cells, considered a property of TSC. The sphere-initiating cells were retrieved in the pSP.Because benign pituitary adenomas do not grow in vitro and failed to expand in immunodeficient mice, the pituitary tumor cell line AtT20 was further used. We identified a SP in this cell line and found it more tumorigenic than the main population (MP). Of the two EMT-regulatory pathways tested, inhibition of Cxcr4 signaling reduced EMT-linked cell motility in vitro as well as xenograft tumor growth, whereas activation of TGFβ had no effect.The tumor pSP showed upregulated expression of the pituitary stem cell marker SOX2. Pituitaries from dopamine receptor D2 knockout (Drd2-/-) mice bearing prolactinomas, contain more pSP, Sox2+ and colony-forming cells than wildtype glands.In conclusion, we detected a SP in pituitary tumors and identified TSC-associated characteristics. Our study may contribute to a better understanding of pituitary tumor pathogenesis and lead to new therapeutic targets. We determined gene expression profiles for 9 human pituitary adenoma samples (5 x NF-A; 4 x GH-A). The samples were obtained immediately after transsphenoidal resection (by the neurosurgeon Dr. van Loon, Division Neurosurgery, University Hospitals Leuven). Informed consent was received from the patients. Hormonal phenotype was determined by the Department of Imaging and Pathology (University Hospitals Leuven). For each sample, total SP and MP cells were sorted by FACS. Separate assays were run subsequently for the two fractions. As such we present data from 18 microarrays.

Project description:Pituitary adenomas cause significant endocrine and mass-related morbidity. Not much is known about mechanisms underlying pituitary tumor pathogenesis. We searched for a side population (SP) in pituitary tumor, representing cells with high efflux capacity and potentially enriching for cancer/tumor stem cells (CSC/TSC). Human pituitary adenomas contain a SP irrespective of hormonal phenotype. This adenoma SP, as well as the further purified SP (pSP) depleted from endothelial and immune cells, enriches for cells that express ‘tumor stemness’ markers and signaling pathways, including epithelial-mesenchymal transition (EMT)-linked factors. The adenomas were found to contain self-renewing sphere-forming cells, considered a property of TSC. The sphere-initiating cells were retrieved in the pSP. Because benign pituitary adenomas do not grow in vitro and failed to expand in immunodeficient mice, the pituitary tumor cell line AtT20 was further used. We identified a SP in this cell line and found it more tumorigenic than the main population (MP). Of the two EMT-regulatory pathways tested, inhibition of Cxcr4 signaling reduced EMT-linked cell motility in vitro as well as xenograft tumor growth, whereas activation of TGFβ had no effect. The tumor pSP showed upregulated expression of the pituitary stem cell marker SOX2. Pituitaries from dopamine receptor D2 knockout (Drd2-/-) mice bearing prolactinomas, contain more pSP, Sox2+ and colony-forming cells than wildtype glands. In conclusion, we detected a SP in pituitary tumors and identified TSC-associated characteristics. Our study may contribute to a better understanding of pituitary tumor pathogenesis and lead to new therapeutic targets. We determined gene expression profiles for 5 human pituitary adenoma samples (all NF-A type). The samples were obtained immediately after transsphenoidal resection (by the neurosurgeon Dr. van Loon, Division Neurosurgery, University Hospitals Leuven). Informed consent was received from the patients. Hormonal phenotype was determined by the Department of Imaging and Pathology (University Hospitals Leuven). For each sample, CD31¯/CD45¯ SP (purified SP or pSP) and pMP cells were sorted by FACS. Separate assays were run subsequently for the two fractions. As such we present data from 10 microarrays.

Project description:In Western countries, colorectal cancer (CRC) is the third most common cancer in both men and women and the second leading cause of cancer-related deaths (approximately 500,000 deaths annually). For CRC, the tumor stage is the main prognostic factor for survival or relapse after surgery. Current staging is based on the AJCC classification which takes into account tumor size/depth, lymph node involvement and distant metastases. Surgical intervention can cure a significant portion of the patients, especially those that are presented in stages I, II or III (around 75% of patients). Patients in stage II undergo surgery only, whereas stage III patients receive adjuvant chemotherapy. However, a major fraction of these patients either have no need for adjuvant treatment (40% stage III) or would benefit when they were given adjuvant therapy in stage II. Therefore, in the current practice, the majority of patients receive not the optimal treatment. An accurate and reliable method that identifies patients with low and high risk for recurrence could improve the selection for adjuvant therapies in these groups, reducing over- or under-treatment. Molecular profiling of mRNA expression by microarray is an approach to identify relevant genes and gene signatures and has been used already for different types of cancer, like breast and HCC. Most studies, however, resulted in their own classification with a specific separation into groups. Most of these microarray studies show remarkably little overlap and it is difficult to find a clear correlation between the molecular classes and prognosis. The results of the studies seem to be center-dependent because of the different microarray techniques used, the small heterogeneous cohorts that are studied and the different clinical parameters used for the evaluation. Recently, we used a mechanism-driven approach to find a correlation between gene expression in HCC and prognosis in which we tried to overcome most shortcomings (van Malenstein et al. CCR 2010). In this study, we want to apply the approach which we used for HCC now in CRC with the aim to improve the prognosis prediction for patients in AJCC stage II and III. We determined the gene expression by microarray in the colon cancer cell line Caco2 and identified the genes that are differentially expressed under hypoxia (72 hours, 2% O2). Using a bioinformatic approach, we used 5 sets of expression data with corresponding clinical information (training: 3 sets, 234 patients and validation: 2 sets, 322 patients). This resulted in a unique 21 gene set with good performance in retrospective analysis. A second improvement we wanted to achieve is the development of a method that can be applied on FFPE material, which would expand the use of the technique to samples outside the university or research setting. We used the nCounter technique that uses hybridization of labeled probes and quantification without an amplification step. We tested our 21 genes on a cohort of 384 well-characterized patients that were collected between 2004 and 2006 at the University Hospitals of Leuven. We compared cells under hypoxia 2% O2 versus 20% O2 conditions. This was done for two cell lines (Caco2 human colorectal adenocarcinoma cell line and HPAC pancreas adenocarcinoma cell line). Each sample has a biological replicate. Samples are hybridized in dye-swap, resulting in 4 hybridizations per cell line.

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Transcriptome analysis of the ron3 mutant

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