The concept of tumor stem cells (TSCs) provides a new paradigm for understanding tumor biology, although it remains unclear whether TSCs will prove to be a more robust model than traditional cancer cell lines. We demonstrate marked phenotypic and genotypic differences between primary human tumor-derived TSCs and their matched glioma cell lines. TSCs derived directly from primary glioblastomas harbor extensive similarities to normal NSC and recapitulate the genotype, gene expression patterns and in vivo biology of human glioblastomas. By contrast, the matched, traditionally grown tumor cell lines do not secondary to in vitro genomic alterations. These findings suggest that TSCs may be a more reliable model than many commonly utilized cancer cell lines for understanding the biology of primary human tumors. Analysis of gene expression data is described in Lee et al., Cancer Cell, 2006.
Tumor stem cells derived from glioblastomas cultured in bFGF and EGF more closely mirror the phenotype and genotype of primary tumors than do serum-cultured cell lines.
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View SamplesThe key lipid metabolism transcription factor sterol regulatory element-binding protein (SREBP)-1a integrates gene regulatory effects of hormones, cytokines, nutrition and metabolites as lipids, glucose or cholesterol via stimuli specific phosphorylation by different MAPK cascades. We have formerly reported the systemic impact of phosphorylation in transgenic mouse models with liver-specific overexpression of the N-terminal transcriptional active domain of SREBP-1a (alb-SREBP-1a) or a MAPK kinase phosphorylation sites deficient variant (alb-SREBP-1aP; (S63A, S117A, T426V)), respectively. Here we investigated the molecular basis of the systemic observation in holistic hepatic gene expression analyses and lipid degrading organelles involved in the pathogenesis of metabolic syndrome, i.e. peroxisomes, by 2D-DIGE and mass spectrometry analyses. Although alb-SREBP-1a mice develop a severe phenotype with visceral adipositas and hepatic lipid accumulation featuring a fatty liver, the hepatic differential gene expression and alterations in peroxisomal protein patterns compared to control mice were surprisingly relative low. In contrast, phosphorylation site deficient alb-SREBP-1aP mice, protected from hepatic lipid accumulation phenotype, showed gross alteration in hepatic gene expression and peroxisomal proteome. Further knowledge based analyzes revealed that overexpression of SREBP-1a favored mainly acceleration in lipid metabolism and indicated a regular insulin signaling, whereas disruption of SREBP-1a phosphorylation resulted in massive alteration of cellular processes including signs for loss of lipid metabolic targets. These results could be the link to a disturbed lipid metabolism that overall resembles a state of insulin resistance.
Inactivation of SREBP-1a Phosphorylation Prevents Fatty Liver Disease in Mice: Identification of Related Signaling Pathways by Gene Expression Profiles in Liver and Proteomes of Peroxisomes.
Sex, Age, Specimen part
View SamplesMajor causes of lipid accumulation in liver are increased import, synthesis or decreased catabolism of fatty acids. The latter is caused by dysfunction of cellular organelle controlling energy homeostasis, i.e. mitochondria. However, peroxisomes appear to be an important organelle in lipid metabolism of hepatocytes, but little is known about their role in the development of non-alcoholic fatty liver disease (NAFLD). To investigate the role of peroxisomes next to mitochondria in excessive hepatic lipid accumulation we used the leptin resistant db/db mice on C57BLKS background, a mouse model that develops hyperphagia induced diabetes with obesity and NAFLD.
Peroxisomes compensate hepatic lipid overflow in mice with fatty liver.
Sex, Age, Specimen part
View SamplesPurpose: MetS consist of five risk factors: elevated blood pressure and fasting glucose, visceral obesity, dyslipidemia and hypercholesterinemia. The physiological impact of lipid metabolism indicated as visceral obesity and hepatic lipid accumulation is still under debate. One major cause of disturbed lipid metabolism might be dysfunction of cellular organelles controlling energy homeostasis, i.e. mitochondria and peroxisomes.
Alteration of Liver Peroxisomal and Mitochondrial Functionality in the NZO Mouse Model of Metabolic Syndrome.
Sex, Age, Specimen part
View SamplesLipodystrophies resemble syndromes of disturbed adipocyte biology or development and severe congenital forms (CGL) lack adipose tissue. The ubiquitous immediate-early gene c-fos is one essential transcription factor to initiate adipocyte differentiation. In a CGL patient we identified a single homozygous point mutation in the promoter of c-fos gene. The mutation facilitates the formation of a novel specific protein/ DNA complex and ubiquitously reduces basal and inducible c-fos transcription activity.
A mutation in the c-fos gene associated with congenital generalized lipodystrophy.
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View SamplesGliomas are mostly incurable secondary to their diffuse infiltrative nature. Thus, specific therapeutic targeting of invasive glioma cells is an attractive concept. As cells exit the tumor mass and infiltrate brain parenchyma, they closely interact with a changing micro-environmental landscape that sustains tumor cell invasion.
Identification of molecular pathways facilitating glioma cell invasion in situ.
Specimen part
View SamplesBackground and aim: The Insulin-like growth factor (IGF) axis is increasingly suggested to be involved in fatty liver disease and progression. We identified IGFBP2 as transcriptional regulatory effect network in liver steatosis and conducted a translational approach of its role in liver pathology from mouse to human, and whether it is influenced by conventional clinical intervention that mitigate hepatic steatosis. Methods: Primary hepatocytes from either C57Bl6 controls, alb-SREBP-1c mice with moderate transgene induced hepatic lipid accumulation or aP2-SREBP-1c mice with massive ectopic hepatic lipid accumulation, were analyzed to identify regulatory networks based on differentially regulated hepatic gene expression. In a translational approach, serum of morbidly obese patients with and without diabetes and biopsy-proven NAFLD were used for ELISA-based validation of mouse data. Moreover, sera of patients undergoing intervention were analyzed and correlated to liver fat content. Results: Comparative knowledge-based transcriptome analysis identified IGFBP2 as top score regulatory effect network between moderate and aggravated fatty liver in mouse models. The reduced expression of IGFBP2 in aP2-SREPB-1c progressed fatty liver associated with Igfbp2 promoter hypermethylation. Reduced secretion of IGFBP2 from aP2-SREBP-1c hepatocytes was reflected in the circulation of the animals. In this phenotype, reductions of IGFBP2 were accompanied by reduced fatty acid oxidation and increased methyltransferase and SIRT activity. Physiologically, IGFBP2 has no direct impact on lipid metabolism but might modulate IGF1 action on de novo lipogenesis. In humans, IGFBP2 levels declined from non-obese men to morbidly obese men with NAFLD and NASH. In intervention study reductions in liver fat correlated with restoration of IGFBP2 serum levels to values found in healthy individuals in morbidly obese patients following bariatric surgery. Conclusion: In hepatic metabolism changes of IGFBP2 abundance is connected to lipid metabolism whereas changes in IGFBP2 secretion were directly reflected in the circulation. IGFBP2 serum concentration correlates with the degree of fatty liver, which seems to be related to plasticity of the adipose tissue. These data provide IGFBP2 as a potential non-invasive biomarker for fatty liver disease directly reflecting the degree of impaired liver function with the potential to indicate progressed fatty liver disease.
Physiological Disturbance in Fatty Liver Energy Metabolism Converges on IGFBP2 Abundance and Regulation in Mice and Men.
Sex, Age
View SamplesThe Skeletal muscle is a metabolic active tissue that secretes various proteins. These so called myokines act auto-, para- and endocrine affecting muscle physiology and exert systemic effects on other tissues and organs. Myokines are also described to play a crucial role in the pathophysiology of metabolic diseases.
Secretome profiling of primary human skeletal muscle cells.
Sex, Specimen part, Subject
View SamplesGoal of experiment: Identification of differentially expressed immune genes from male and female BWF1 lupus-prone mice. (Female incidence is higher than male--attempting to find sex hormone regulated genes that may contribute to this difference). Whole spleen was taken from pre-lupus (4 months old) BWF1 (females are lupus-prone) male and female mice. Preparation of cDNA. Double-stranded cDNA was synthesized from purified RNA. The first strand was synthesized by incubating 5 g of RNA with 100 pg/ml T7-(dT)24 primer (HPLC purified DNA primer sequence: 5-GGCCAGTGAATTGTAATACG ACTCACTATAGGGAGGCGG-(dT)24 -3 Genset Corp, San Diego, CA) at 70C for 10 minutes. Samples were incubated for 1 hour at 42C with the following mix: 1X first strand buffer, 10 mM dithiothreitol, 500 M each dNTP, 200 U SuperScript II in diethylpyrocarbonate (DEPC)-treated water up to 20 l. Second strand synthesis was performed by incubating the first strand with the following mix for 2 hours at 16C: 1X second strand reaction buffer, 200 M dntps, 10 U E. coli DNA ligase, 40 U E coli DNA Polymerase I, 2 U of E. coli RNase H up to 150 l with DEPC-treated water (all reagents were contained in SuperScript Choice System for cDNA Synthesis, Invitrogen). A phenol/chloroform extraction was performed on the ds-cDNA preparation before biotin-labeled cRNA was generated. Synthesis and fragmentation of biotin-labeled cRNA (in vitro transcription). The ENZO BioArrayTM HighYieldTM RNA Transcript Labeling Kit (T7) (Enzo diagnostics, Inc., Farmingdale, NY) was used to produce large amounts of hybridizable biotin-labeled RNA targets by in vitro transcription from the ds-cDNA. The following mix was incubated at 37C for 5 hours: 1 g of ds-cDNA, 1X HY reaction buffer, 1X biotin labeled ribonucleotides, 1X dithiothreitol, 1X T7 RNA Polymerase. Biotin-labeled cRNA was run over RNeasy spin columns (Qiagen), quantified, and run on an agarose gel to visualize the size distribution of labeled transcripts. Twenty micrograms of cRNA was incubated with 1X fragmentation buffer for 35 minutes at 94C. (5X fragmentation buffer: 200 mM Tris-acetate, pH 8.1, 500 mM KOAc, 150 mM MgOAc). After fragmentation, the samples were stored at -20C until the hybridization was performed. Sample hybridization. Oligonucleotide microarrays (MGU74v2 A, B, and C GeneChip probe arrays; Affymetrix) were hybridized with labeled cRNA derived from spleens from individual mice. For each array,15 g of fragmented cRNA was mixed with a hybridization cocktail consisting of 1X hybridization buffer (2X hybridization buffer: 100 mM MES, 1 M [Na+], 20 mM EDTA, 0.01% Tween), 0.5 mg/ml acetylated BSA (Invitrogen), 0.1 mg/ml herring sperm DNA (Promega), and water (BioWhittaker) up to 300 l). Biotin labeled cRNA transcripts of the E. coli and P1 bacteriophage genes, BioB, bioC, bioD, and cre (GeneChip Eukaryotic Hybridization control kit, Affymetrix) were spiked into each hybridization mix at 1.5, 5, 25, and 100 pM to evaluate sample hybridization efficiency for each array. The hybridization cocktail was heated to 99C and then 45C for 5 minutes each before it was centrifuged to remove any insoluble material. The array was equilibrated to room temperature, moistened with 1X hybridization buffer, and incubated for 10 minutes at 45C with rotation. After incubation, the buffer solution was removed from the array. The array was filled with 300 l of the hybridization cocktail, placed in a rotisserie box in a 45C oven, and incubated for 16 hours while rotating at 60 rpm. Washing and staining of array. The hybridization cocktail was removed and the GeneChip Fluidics Station 400 (Affymetrix) with Microarray Suite software (Affymetrix) was used to wash and stain the probe arrays with the following protocol: 10 cycles of 2 mixes/cycle with wash buffer A at 25C, 4 cycles of 15 mixes/cycle with wash buffer B at 50C, 30 minute incubation with staining solution at 25C, 10 cycles of 4 mixes/cycle with wash buffer A at 25C. Wash buffer A -- non-stringent wash buffer (6X sodium chloride sodium phosphate + ethylenediaminetetraacetic acid (SSPE), 0.01% Tween-20). (20X SSPE: 3 M NaCl, 0.2 M NaH2PO4, 0.02 EDTA) (BioWhittaker). Wash buffer B stringent wash buffer (100mM MES, 0.1 M [Na+], 0.1% Tween 20). Staining solution (1X 2-(N-Morpholino)ethanesulfonic Acid (MES) stain buffer, 2 mg/ml acetylated BSA, 10 g/ml Streptavidin Phycoerythrin (SAPE), and water up to 600 l). (12X MES stain buffer: 1.22 M MES, 0.89 M [Na+]). Analysis. After staining, the probe arrays were scanned using the GeneChip 3000 Scanner (Affymetrix) with Microarray Suite software (Affymetrix). Technical and assay variation between arrays was corrected for by multiplying or dividing the overall intensity of each array by a scaling factor so that the overall intensity of each array was equivalent to facilitate comparison analysis.
Identification of candidate genes that influence sex hormone-dependent disease phenotypes in mouse lupus.
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View SamplesThis is Rembrandt gene expression data (Affymetrix HG-U133Plus2).
Rembrandt: helping personalized medicine become a reality through integrative translational research.
Specimen part, Disease, Disease stage
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