For more than a decade, microarrays have been a powerful and widely used tool to explore the transcriptome of biological systems. However, the amount of biological material from cell sorting or laser capture microdissection is much too small to perform microarray studies. To address this issue, RNA amplification methods have been developed to generate sufficient targets from picogram amounts of total RNA to perform microarray hybridisation. In this study, four commercial protocols for amplification of picograms amounts of input RNA for microarray expression profiling were evaluated and compared. The quantitative and qualitative performances of the methods were assessed. Microarrays were hybridised with the amplified targets and the amplification protocols were compared with respect to the quality of expression profiles, reproducibility within a concentration range of input RNA, and sensitivity.
Evaluation of methods for amplification of picogram amounts of total RNA for whole genome expression profiling.
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View SamplesThe aim of this study was to characterize expression profiles of visceral and subcutaneous adipose tissue in children. Adipose tissue samples were collected from children having elective surgery (n=71, [54 boys], 6.0 +- 4.3 years). Affymetrix microarrays (n=20) were performed to characterize the functional profile and identify genes of interest in adipose tissue. Visceral adipose tissue had an overrepresentation of Gene Ontology themes related to immune and inflammatory responses and subcutaneous adipose tissue had an overrepresentation of themes related to adipocyte growth and development. Likewise, qPCR performed in the whole cohort showed a 30-fold increase in haptoglobin (P < 0.005), 7-fold increase in IL-10 (P < 0.001), 8-fold decrease in VEGF (P < 0.01) and a 28-fold decrease in TBOX15 (P < 0.001) in visceral compared to subcutaneous adipose tissue.The inflammatory pattern in visceral adipose tissue may represent an early stage of the adverse effects of this depot, and combined with chronic obesity, may contribute to increased metabolic and cardiovascular risk.
An early inflammatory gene profile in visceral adipose tissue in children.
Sex, Specimen part
View SamplesPrimary liver tumours include hepatocellular carcinomas (HCC), cholangiocarcinomas (CC) and a group of rare tumours exhibiting biliary and hepatocytic differentiation called combined hepatocholangiocarcinomas (cHCC-CC). To better define this latter group, we take advantage of a series of these tumours based on their morphological characteristics and we performed transcriptional analysis allowing thereafter global comparison with published data. We show that most cHCC-CCs express progenitor cell traits, are committed to biliary lineage and are mainly associated to the activation of Wnt/beta-catenin and TGFbeta signalling pathways. Wnt/beta-catenin pathway activation in cHCC-CC is evidenced by the expression of both its direct targets such as LEF1 and EPCAM. In addition, extracellular matrix (ECM) genes and ECM-remodelling genes which are upon the control of TGF profibrotic program were found up-regulated in cHCC-CC. Interestingly, we show that CC and most cHCC-CC share characteristics associated to a subtype of poorly differentiated HCC suggesting that these tumours could originate from a stem/progenitor cell. The plasticity of these cells may explain the phenotypical heterogeneity of these tumors with the maintenance of some hepatocellular differentiation features such as albumin expression. Interestingly, this is shared by at least one third of CC, raising the hypothesis of a potential continuum between CC, cHCC-CC and poorly differentiated HCC.
Combined hepatocellular-cholangiocarcinomas exhibit progenitor features and activation of Wnt and TGFβ signaling pathways.
Sex, Specimen part
View SamplesOverexpression of the Polycomb group protein Enhancer of Zeste Homolog 2 (EZH2) occurs in diverse malignancies, including prostate cancer, breast cancer, and glioblastoma multiforme (GBM) (1). Based on its ability to modulate transcription of key genes implicated in cell cycle control, DNA repair and cell differentiation, EZH2 is believed to play a crucial role in tissue-specific stem cell maintenance and tumor development. Here we show that targeted pharmacologic disruption of EZH2 by the S-adenosylhomocysteine hydrolase inhibitor 3-Deazaneplanocin A (DZNep), or its specific down-regulation by shRNA, strongly impairs GBM cancer stem cell self-renewal in vitro and tumor-initiating capacity in vivo. Using genome-wide expression analysis of DZNep-treated GBM cancer stem cells, we found the expression of c-myc, recently reported to be essential for GBM cancer stem cells, to be strongly repressed upon EZH2 depletion. Specific shRNA-mediated down-regulation of EZH2 in combination with chromatin immunoprecipitation (ChIP) experiments revealed that c-myc is a direct target of EZH2 in GBM cancer stem cells. Taken together, our observations provide evidence that direct transcriptional regulation of c-myc by EZH2 may constitute a novel mechanism underlying GBM cancer stem cell maintenance and suggest that EZH2 may be a valuable new therapeutic target for GBM management.
EZH2 is essential for glioblastoma cancer stem cell maintenance.
Specimen part, Treatment
View SamplesInsulin-like growth factor receptor-1 (IGF-1R) inhibition could be a relevant therapeutic approach in small cell lung cancer (SCLC) given the importance of an IGF-1R autocrine loop and its role in DNA damage repair processes. We assessed IGF-1R and pAkt protein expression in 83 SCLC human specimens. The efficacy of R1507 (a monoclonal antibody directed against IGF-1R) alone or combined with cisplatin or ionizing radiation (IR) was evaluated in H69, H146 and H526 cells in vitro and in vivo. Innovative genomic and functional approaches were conducted to analyze the molecular behavior under the different treatment conditions. A total of 53% and 37% of human specimens expressed IGF-1R and pAkt, respectively. R1507 demonstrated single agent activity in H146 and H526 cells but not in H69 cells. R1507 exhibited synergistic effects with both Cisplatin and IR in vitro. The triple combination R1507-Cisplatin-IR led to a dramatic delay in tumor growth compared to Cisplatin-IR in H526 cells. Analyzing the apparent absence of antitumoral effect of R1507 alone in vivo, we observed a transient reduction of IGF-1R staining intensity in vivo, concomitant to the activation of multiple cell surface receptors and intracellular proteins involved in proliferation, angiogenesis and survival. Finally, we identified that the nucleotide excision repair pathway (NER) was mediated after exposure to R1507-CDDP and R1507-IR in vitro and in vivo. In conclusion, adding R1507 to the current standard Cisplatin-IR doublet reveals remarkable chemo- and radiosensitizing effects in selected SCLC models and warrants to be investigated in the clinical setting.
IGF-1R targeting increases the antitumor effects of DNA-damaging agents in SCLC model: an opportunity to increase the efficacy of standard therapy.
Specimen part, Treatment
View SamplesActivated NOTCH1 induces T-ALL in mice when transduced in bone marrow (BM) cells. T-ALL cells activate the calcineurin/NFAT pathway in vivo (Medyouf H. et al. Nat Med 2007 [PMID 17515895]).
Leukemia-initiating cell activity requires calcineurin in T-cell acute lymphoblastic leukemia.
Specimen part, Treatment
View SamplesBariatric surgery is the most effective therapy of severe human obesity. It is associated with improvements in metabolic and non metabolic co-morbidities which are thought to be mediated by a decrease of adipose tissue inflammation. However, the molecular mechanisms behind these beneficial effects are poorly understood. We analyzed expression profiles in subcutaneous adipose tissue from 22 obese women before and 3 months after surgery using the RNA-seq technology. Of 15,972 detected genes, 1214 were differentially expressed after surgery. Upregulated genes were mostly involved in the basal cellular machinery. Downregulated genes were enriched in metabolic functions of adipose tissue. At baseline, we identified 26 modules of coexpressed genes. The four most stable modules reflected the innate and adaptive immune responses of adipose tissue, including a general signature of innate immune cells, an adaptive immune response elicited by T lymphocytes, a neutrophil-mediated inflammatory signature and an interferon-signaling pathway, respectively. After surgery, a few crucial molecules involved in chemotaxis and activation of immune cells were disconnected from their respective networks. These molecules may represent therapeutic targets against adipose inflammation. Overall design: mRNA sequencing of subcutaneous adipose tissue (SAT) samples from 22 obese women before and 3 months after bariatric surgery
Bariatric Surgery Induces Disruption in Inflammatory Signaling Pathways Mediated by Immune Cells in Adipose Tissue: A RNA-Seq Study.
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View SamplesSkeletal muscle actin mice (Crawford et al., (2002) Mol Cell Biol 22, 5587) were crossed with cardiac actin transgenic mice (termed "ACTC^Coco" or "Coco" for short), to produce mice that had cardiac actin instead of skeletal muscle actin in their skeletal muscles (termed "ACTC^Co/KO" or for short "Coco/KO"). Microarray analysis using the Illumina mouse-6 v1.1 expression beadchip was performed on RNA extraced from the soleus muscle of Coco/KO mice and wildtype mice, to confirm the swith in actin isoform expression, and to determine what other differences might exist between wildtype mice and the Coco/KO mice.
Rescue of skeletal muscle alpha-actin-null mice by cardiac (fetal) alpha-actin.
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View SamplesLPA is a natural bioactive lipid with growth factor-like functions due to activation of series of six G protein-coupled receptors (LPA1-6).
Identification of heparin-binding EGF-like growth factor (HB-EGF) as a biomarker for lysophosphatidic acid receptor type 1 (LPA1) activation in human breast and prostate cancers.
Cell line
View SamplesRod-derived Cone Viability Factor (RdCVF, alias nxnl1) is a retina-specific protein identified for its therapeutic potential in supporting cone survival during retinal degeneration.
The disruption of the rod-derived cone viability gene leads to photoreceptor dysfunction and susceptibility to oxidative stress.
Disease, Disease stage
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