We have performed a genome-wide analysis of common genetic variation controlling differential expression of transcript isoforms in the CEU HapMap population using a comprehensive exon tiling microarray covering 17,897 genes. We detected 324 genes with significant associations between flanking SNPs and transcript levels. Of these, 39% reflected changes in whole gene expression and 55% reflected transcript isoform changes such as splicing variants (exon skipping, alternate splice site usage, intron retention), differential 5 UTR (initiation of transcription) usage, and differential 3 UTR (alternative polyadenylation) usage.
Genome-wide analysis of transcript isoform variation in humans.
Sex
View SamplesMEG3 (Maternally Expressed Gene 3) is a non-coding RNA that is highly expressed in the normal human brain and pituitary. Expression of MEG3 is lost in gonadotroph-derived clinically non-functioning pituitary adenomas. Meg3 knock-out mice were generated to identify targets and potential functions of this gene in embryonic development and tumorigenesis. Gene expression profiles were compared in the brains of Meg3-null embryos and wild-type litter-mate controls using microarray analysis. Microarray data were analyzed with GeneSifter which uses Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and Gene Ontology (GO) classifications to identify signaling cascades and functional categories of interest within the data set. Differences were found in signaling pathways and ontologies related to angiogenesis between wild-type and knock-out embryos. Quantitative RT-PCR and histological staining showed increased expression of some VEGF pathway genes and increased cortical microvessel density in the knock-out embryos. These results are consistent with reported increases in VEGF signaling observed in human clinically non-functioning pituitary adenomas. In conclusion, Meg3 may play an important role in control of vascularization in the brain and may function as a tumor suppressor by preventing angiogenesis.
Increased expression of angiogenic genes in the brains of mouse meg3-null embryos.
Specimen part
View SamplesThe entorhinal cortex of the mouse seems to be sensitive to molecular mechanisms that have been linked to the pathology of Alzheimer's disease. In this microarray study we are interested in comparing the expression profile of the left versus the right EC of the mouse, in order to understand if there is a significant difference in gene expression that might reveal any insights into the differential activation of these areas.
Molecular drivers and cortical spread of lateral entorhinal cortex dysfunction in preclinical Alzheimer's disease.
Age, Specimen part
View SamplesTwo colon cancer cell lines are under study. SW480 and SW620. The first one is derived from primary cancer, SW620 are from lymphnode metastatic sites. they both comes from the sampe patient. Polisomal RNA fractions from the two isogenic colon cancer cells lines was purified by sucrose gradient and hybridized on affymetrix hgu133a chips. this study is complementary to the series GSE1323 were total RNA was used instead. Comparison between the polysomal fraction chips and the total RNA chips is performed and the analysis proposed in a paper from the authors (at the moment in preparation).
Global alterations in mRNA polysomal recruitment in a cell model of colorectal cancer progression to metastasis.
No sample metadata fields
View SamplesSW480 and SW620 are colon cancer cells lines derived from a primary tumor and a corresponding metastasis from the same individual. The numbers indicate the three indipendent replicate RNA samples processed. Three different software packages were used in parallel for signal calculation: Affymetrix microarray suite 5.0, DNA-Chip analyzer, and Robust multi-array analyses.
Global alterations in mRNA polysomal recruitment in a cell model of colorectal cancer progression to metastasis.
No sample metadata fields
View SamplesTumor-associated blood vessels differ from normal vessels at the morphological and molecular level. Proteins that are only present on tumor vessels may serve as biomarkers and as therapeutic targets for inhibition of angiogenesis in cancer. Comparing the transcriptional profiles of blood vascular endothelium from human invasive bladder cancer and from normal bladder tissue, we found several markers that could serve as novel biomarkers or therapeutic targets.
Endocan is upregulated on tumor vessels in invasive bladder cancer where it mediates VEGF-A-induced angiogenesis.
Sex, Disease stage
View SamplesPrimary tumor growth induces host tissue responses that are believed to support and promote tumor progression. Identification of the molecular characteristics of the tumor microenvironment and elucidation of its crosstalk with tumor cells may therefore be crucial for improving our understanding of the processes implicated in cancer progression, identifying potential therapeutic targets, and uncovering stromal gene expression signatures that may predict clinical outcome. A key issue to resolve, therefore, is whether the stromal response to tumor growth is largely a generic phenomenon, irrespective of the tumor type, or whether the response reflects tumor-specific properties. To address similarity or distinction of stromal gene expression changes during cancer progression, oligonucleotide-based Affymetrix microarray technology was used to compare the transcriptomes of laser-microdissected stromal cells derived from invasive human breast and prostate carcinoma. Invasive breast and prostate cancer-associated stroma was observed to display distinct transcriptomes, with a limited number of shared genes. Interestingly, both breast and prostate tumor-specific dysregulated stromal genes were observed to cluster breast and prostate cancer patients, respectively, into two distinct groups with statistically different clinical outcomes. By contrast, a gene signature that was common to the reactive stroma of both tumor types did not have survival predictive value. Univariate Cox analysis identified genes whose expression level was most strongly associated with patient survival. Taken together, these observations suggest that the tumor microenvironment displays distinct features according to the tumor type that provides survival-predictive value.
Identification of prognostic molecular features in the reactive stroma of human breast and prostate cancer.
Specimen part
View SamplesMetastasis depends on the ability of tumor cells to establish a relationship with the newly seeded host tissue that is conducive to their survival and proliferation. Recent evidence suggests that tumor cells regulate their own dissemination by preparing permissive metastatic niches within host tissues. However, the factors that are implicated in rendering tissues permissive for metastatic tumor growth have yet to be fully elucidated. Breast tumors arising during pregnancy display highly aggressive behaviour and early metastatic proclivity, raising the possibility that pregnancy may constitute a physiological condition of permissiveness for tumor dissemination. We show that during murine gestation, both the rate and degree of metastatic tumor growth are enhanced irrespective of tumor type and that decreased natural killer (NK) cell activity is responsible for the observed increase in experimental metastasis. We identify gene expression changes in pregnant mouse lung and liver that bear striking similarity with reported pre-metastatic niche signatures and several of the up-regulated genes are indicative of myeloid-cell infiltration. We provide evidence, that CD11b+ Gr-1+ myeloid-derived suppressor cells accumulate in pregnant mice and exert an inhibitory effect on NK cell activity, thereby enhancing metastatic tumor growth. MDSC have never been evoked in the context of pregnancy and our observations suggest that they may represent a further shared mechanism of immune suppression occurring during gestation and tumor growth.
Myeloid-derived suppressor cells are implicated in regulating permissiveness for tumor metastasis during mouse gestation.
Specimen part
View SamplesWe implemented an optimized processing, using alternative Chip Description Files (CDFs) and fRMA normalization, which improve the quality of downstream analysis.
Accurate data processing improves the reliability of Affymetrix gene expression profiles from FFPE samples.
Specimen part
View SamplesSenescence of stromal fibroblasts has been linked to establishment of cancer associated fibroblasts (CAF) and aging-associated increase of tumors. However, in clinically occurring carcinomas, density and proliferation of CAFs are frequently increased rather than decreased. We previously showed that genetic deletion or down-modulation of the canonical Notch effector CSL/RBP-J? in skin dermal fibroblasts is sufficient for CAF activation with consequent development of multifocal keratinocyte tumors. We now show that CSL deletion or knockdown induces senescence of primary fibroblasts derived from dermis, oral mucosa, breast and lung. CSL functions in these cells as a constitutive direct repressor of multiple senescence- and CAF-effector genes. At the same time, it physically interacts with p53, repressing its activity, and p53 activation provides a failsafe mechanism against compromised CSL function. Concomitant loss of CSL and p53 overcomes fibroblast senescence, enhances expression of CAF effector genes and, in vivo, promotes tumour and stromal cell expansion. Together, the findings support a CAF activation/stromal evolution model under convergent CSL/p53 control. Overall design: Human Dermal Fibroblasts were transfected with two different siRNA against CSL in parallel with a control siRNA. Total RNA was extracted 3 days post-transfection, followed by RNA-Seq analysis.
Combined CSL and p53 downregulation promotes cancer-associated fibroblast activation.
No sample metadata fields
View Samples