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GSE14986
Homo sapiens
25 Downloadable Samples
Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Emergence of antiestrogen-resistant cells in MCF-7 cells during suppression of estrogen signaling is a widely accepted model of acquired breast cancer resistance to endocrine therapy. To obtain insight into the genomic basis of endocrine therapy resistance, we characterized MCF-7 monoclonal sublines that survived 21-day exposure to tamoxifen (T-series sublines) or fulvestrant (F-series sublines) and sublines unselected by drugs (U-series). All T/F-sublines were resistant to the cytocidal effects of both tamoxifen and fulvestrant. However, their responses to the cytostatic effects of fulvestrant varied greatly, and their remarkably diversified morphology showed no correlation with drug resistance. mRNA expression profiles of the U-sublines differed significantly from those of the T/F-sublines, whose transcriptomal responsiveness to fulvestrant was largely lost. A set of genes strongly expressed in the U-sublines successfully predicted metastasis-free survival of breast cancer patients. Most T/F-sublines shared highly homogeneous genomic DNA aberration patterns that were distinct from those of the U-sublines. Genomic DNA of the U-sublines harbored many aberrations that were not found in the T/F-sublines. These results suggest that the T/F-sublines are derived from a common monoclonal progenitor that lost transcriptomal responsiveness to antiestrogens as a consequence of genetic abnormalities many population doublings ago, not from the antiestrogen-sensitive cells in the same culture during the exposure to antiestrogens. Thus, the apparent acquisition of antiestrogen resistance by MCF-7 cells reflects selection of preexisting drug-resistant subpopulations without involving changes in individual cells. Our results suggest the importance of clonal selection in endocrine therapy resistance of breast cancer.
Publication Title
Antiestrogen-resistant subclones of MCF-7 human breast cancer cells are derived from a common monoclonal drug-resistant progenitor.
Sample Metadata Fields
Specimen part, Cell line, Treatment
View Samples- Homo sapiens
- 24 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Cells transiently adapt to hypoxia by globally decreasing protein translation. However, specific proteins needed to respond to hypoxia evade this translational repression. The mechanisms of this phenomenon remain unclear. We screened for and identified small molecules that selectively decrease HIF-2a translation in an mTOR independent manner, by enhancing the binding of Iron Regulatory Protein 1 (IRP1) to a recently reported Iron-Responsive Element (IRE) within the 5-untranslated region (UTR) of the HIF-2a message. Knocking down the expression of IRP1 by shRNA abolished the effect of the compounds. Hypoxia de-represses HIF-2a translation by disrupting the IRP1- HIF-2a IRE interaction. Thus, this chemical genetic analysis describes a molecular mechanism by which translation of the HIF-2a message is maintained during conditions of cellular hypoxia through inhibition of IRP-1 dependent repression. It also provides the chemical tools for studying this phenomenon.
Publication Title
Small-molecule inhibitors of HIF-2a translation link its 5'UTR iron-responsive element to oxygen sensing.
Sample Metadata Fields
No sample metadata fields
View Samples- Rattus norvegicus
- 12 Downloadable Samples
Illumina HiSeq 3000
Description
Reduced eukaryotic Initiation Factor 2 (eIF2)a phosphorylation (p-eIF2a) enhances protein synthesis, memory formation, and addiction-like behaviors. However, p-eIF2a has not been examined with regard to psychoactive cannabinoids and cross-sensitization. Here, we find that a cannabinoid receptor agonist (WIN 55,212-2 mesylate [WIN]) reduced p-eIF2a in vitro by upregulating GADD34 (PPP1R15A), the recruiter of protein phosphatase 1 (PP1). The induction of GADD34 was linked to ERK/CREB signaling and to CREB-binding protein (CBP)-mediated histone hyperacetylation at the Gadd34 locus. In vitro, WIN also upregulated eIF2B1, an eIF2 activator subunit. We next found that WIN administration in vivo reduced p-eIF2a in the nucleus accumbens of adolescent, but not adult, rats. By contrast, WIN increased dorsal striatal levels of eIF2B1 and ?FosB among both adolescents and adults. In addition, we found cross-sensitization between WIN and cocaine only among adolescents. These findings show that cannabinoids can modulate eukaryotic initiation factors, and they suggest a possible link between p-eIF2a and the gateway drug properties of psychoactive cannabinoids. Overall design: RNAseq from PC12 cell line with a 6 hour DMSO or WIN treatment.
Publication Title
Cannabinoid Modulation of Eukaryotic Initiation Factors (eIF2α and eIF2B1) and Behavioral Cross-Sensitization to Cocaine in Adolescent Rats.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 6 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Activation of oncogenic ras pathway accounts for up to 90% low-grade superficial urothelial carcinomas of bladder, and p53 deficiency is very common in high-grade muscle invasive carcinomas. These two pathways in bladder urothelial tumorigenesis used to be considered divergent and their potential collaboration has not been illustrated.
Publication Title
Oncogenic HRAS Activates Epithelial-to-Mesenchymal Transition and Confers Stemness to p53-Deficient Urothelial Cells to Drive Muscle Invasion of Basal Subtype Carcinomas.
Sample Metadata Fields
Age, Specimen part
View Samples- Mus musculus
- 19 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
We compared gene expression profiles of aire-deficient and wild-type littermate thymic medullary epithelial cells. This was done in order to determine whether Aire's effects differed among strains, and also among individuals of the same strain.
Publication Title
The variable immunological self: genetic variation and nongenetic noise in Aire-regulated transcription.
Sample Metadata Fields
Sex
View Samples- Mus musculus
- 9 Downloadable Samples
- Affymetrix Murine Genome U74A Version 2 Array (mgu74av2)
Description
The aim of this study is to identify genes implicated in the early steps of the autoimmune process, prior to inflammation in type 1 diabetes. Early Insulin AutoAntibodies (E-IAA) have been used as subphenotypic marker to select individual animals as type 1 diabetes prone and to compare gene expression patterns with insulin autoantibody negative NOD.
Publication Title
Early over expression of messenger RNA for multiple genes, including insulin, in the Pancreatic Lymph Nodes of NOD mice is associated with Islet Autoimmunity.
Sample Metadata Fields
Age
View Samples- Homo sapiens
- 6 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
The p53 tumor suppressor is a DNA damage responsive sequence-specific transcriptional activator. The sustained activation of the p53 response is incompatible with cell growth and viability. To circumvent this issue, a variety of negative feedback loops exist to limit the duration of p53 activation. Despite our understanding of p53-regulation, very little is known about the effect of transient p53 activation on the long term expression of p53 target genes. Here we used a temperature sensitive variant of p53 and oligonucleotide microarrays to monitor gene expression during and following reversible p53 activation. The expression of most p53-induced transcripts was rapidly reversible, consistent with active mRNA decay. Representative 3UTRs derived from short-lived transcripts (i.e. DDB2 and GDF15) conferred instability on a heterologous mRNA while 3UTRs derived from more stable transcripts (i.e. CRYAB and TP53I3) did not. The 3UTRs derived from unstable p53-induced mRNAs were significantly longer than those derived from stable mRNAs. These 3UTRs had high uridine and low cytosine content, leading to a higher density of U-, AU- and GU-rich sequences. Remarkably, short-lived p53 targets were induced faster reaching maximum transcript levels earlier than the stable p53-targets. Taken together, the p53 transcriptional response has evolved with primarily short-lived target mRNAs and that post-transcription processes play a prominent role in the p53 response.
Publication Title
The role of mRNA decay in p53-induced gene expression.
Sample Metadata Fields
Specimen part, Cell line
View Samples- Homo sapiens
- 20 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Lymphoblast cells from a patient with Freidriech's Ataxia were incubated with pyrrole-imidazole polyamides targeted to the GAA triplet repeat in the intron 1. The polyamides were shown in cell culture to increase levels of endogenous frataxin mRNA. A normal sibling derived lymphoblast cell line was used as a control.
Publication Title
DNA sequence-specific polyamides alleviate transcription inhibition associated with long GAA.TTC repeats in Friedreich's ataxia.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 16 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
These experiments were done to compare the gene expression profiles in CD4+ T cells responding to antigen presented by dendritic cells transiently or persistently. Some treatments include the activation of the dendritic cells by CD40 engagement.
Publication Title
Sustained antigen presentation can promote an immunogenic T cell response, like dendritic cell activation.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 52 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
The transcription factor Foxp3 is usually considered the master regulator for the CD4+CD25+ "Treg" lineage, which plays a key role in controlling immune and autoimmune responses, and is characterized by a unique transcriptional signature. We have performed a meta-analysis of this signature in Treg cells in several conditions to delineate the elements that can be ascribed to T cell activation, TGFbeta signaling, or Foxp3 itself. We find that these influences synergize to activate many of the signatures components. Foxp3 and TGFbeta signaling have interconnected relationships, as Foxp3 is induced by TGFbeta while enhancing TGFbetas positive feedback loop. Much of the Treg signature cannot be ascribed to Foxp3, as it contains gene clusters that are co-regulated, but cannot be transactivated, by Foxp3. This suggests that the Treg lineage is specified at a higher level of regulation, upstream of Foxp3, which does control some of the lineages essential immunoregulatory attributes.
Publication Title
Foxp3 transcription-factor-dependent and -independent regulation of the regulatory T cell transcriptional signature.
Sample Metadata Fields
Age, Specimen part
View Samples