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GSE20081
Homo sapiens
16 Downloadable Samples
Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
The human steroid receptor RNA activator (SRA) gene encodes both non-coding RNAs (ncRNAs) and protein-generating isoforms. However, the breadth of endogenous target genes that might be regulated by SRA RNAs remains largely unknown. To address this, we depleted SRA RNA in two human cancer cell lines (HeLa and MCF-7) with small interfering RNAs, then assayed for changes in gene expression by microarray analyses using Affymetrix HGU133+2 arrays. We also tested if SRA depletion affects estradiol-regulated genes in MCF-7 breast cancer cells.
Publication Title
Research resource: expression profiling reveals unexpected targets and functions of the human steroid receptor RNA activator (SRA) gene.
Sample Metadata Fields
Cell line
View Samples- Mus musculus
- 7 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Similar to the bone marrow, the mammary gland contains a distinct population of Hoechst-effluxing side population cells, MG-SPs. To better characterize MG-SPs, their microarray gene profiles were compared to the remaining cells, which retain Hoechst dye (MG-NSPs). For analysis, gene ontology (GO) that describes genes in terms of biological processes and ontology traverser (OT) that performs enrichment analysis were utilized. OT showed that MG-SP specific genes were enriched in the GO categories of cell cycle regulation and checkpoints, multi-drug resistant transporters, organogenesis, and vasculogenesis. The MG-NSP upregulated genes were enriched in the GO category of cellular organization and biogenesis which includes basal epithelial markers, p63, smooth muscle actin (SMA), myosin, alpha-6 integrin, cytokeratin (CK) 14, as well as luminal markers, CK8 and CD24. Additional studies showed that a higher percentage of MG-SPs exist in the G1 phase of the cell cycle compared to the MG-NSPs. G1 cell cycle block of MG-SPs may be explained by higher expression of cell cycle negative regulatory genes such as TGF-beta2 (transforming growth factor-beta2), IGFBP-5 (insulin like growth factor binding protein-5), P18 INK4C and Wnt-5a (wingless-5a). Accordingly, a smaller percentage of MG-SPs expressed nuclear b-catenin, possibly as a consequence of the higher expression of Wnt-5a. In conclusion, microarray gene profiling suggests that MG-SPs are a lineage deficient mammary gland sub-population expressing key genes involved in cell cycle regulation, development and angiogenesis.
Publication Title
Transcriptional profiling of mammary gland side population cells.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 11 Downloadable Samples
- Affymetrix Human Genome U133A 2.0 Array (hgu133a2)
Description
Substantial evidence implicates IGF-I signaling in the development and progression of breast cancer. To identify transcriptional targets of IGF action in breast cancer cells, we performed gene expression profiling (>22,000 RNA transcripts) of IGF-I-stimulated MCF-7 cells, a well characterized breast cancer cell line that is highly responsive to IGFs. We defined an IGF-I gene signature pattern of hundreds of genes either up-regulated or down-regulated at both 3 and 24 hrs in vitro. After removing genes considered generic to cell proliferation, the signature was examined in four different public profile datasets of clinical breast tumors (representing close to 1000 patients), as well as in profile datasets of experimental models for various oncogenic signaling pathways. Genes with early and sustained regulation by IGF-I were highly enriched for transcriptional targets of the estrogen, Ras, and PI3K/Akt/mTOR pathways. The IGF-I signature appeared activated in most estrogen receptor-negative (ER-) clinical breast tumors and in a substantial subset (~25%) of ER+ breast tumors. Patients with tumors showing activation of the IGF-I signature tended to have a shorter time to disease recurrence (including patients not receiving adjuvant therapy), both when considering all patients and the subset of ER+ patients. We found evidence for cross-talk and common transcriptional endpoints between the IGF-I and estrogen systems. Our results support the idea that the IGF-I pathway is one mechanism by which breast tumors may acquire hormone independence and a more aggressive phenotype.
Publication Title
Insulin-like growth factor-I activates gene transcription programs strongly associated with poor breast cancer prognosis.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 59 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
To investigate molecular mechanisms of resistance, we used two different in vivo xenograft models of estrogen receptor-positive (ER+) breast cancer, with or without HER2 over-expression (MCF7/HER2-18 and MCF7 wt, respectively). Mice with established tumors were assigned to the following treatment groups: continued estrogen supplementation (E2), estrogen deprivation (ED), ED plus tamoxifen (Tam), all with or without the EGFR tyrosine kinase inhibitor gefinitinib (G). Another group received ED plus the antiestrogen fulvestrant (MCF7 wt only). Tumors with acquired or de novo resistance to these endocrine therapies were profiled for mRNA expression using Affymetrix Genechip arrays.
Publication Title
Development of resistance to targeted therapies transforms the clinically associated molecular profile subtype of breast tumor xenografts.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 46 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
To investigate molecular mechanisms of resistance, we used two different in vivo xenograft models of estrogen receptor-positive (ER+) breast cancer, with or without HER2 over-expression (MCF7/HER2-18 and MCF7 wt, respectively). Mice with established tumors were assigned to the following treatment groups: continued estrogen supplementation (E2), estrogen deprivation (ED), ED plus tamoxifen (Tam), all with or without the EGFR tyrosine kinase inhibitor gefinitinib (G). Another group received ED plus the antiestrogen fulvestrant (MCF7 wt only). Tumors with acquired or de novo resistance to these endocrine therapies were profiled for mRNA expression using Affymetrix Genechip arrays.
Publication Title
Development of resistance to targeted therapies transforms the clinically associated molecular profile subtype of breast tumor xenografts.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 29 Downloadable Samples
- Affymetrix Human Genome U133A 2.0 Array (hgu133a2)
Description
The scaffold attachment factors SAFB1 and SAFB2 are paralogs, which are involved in cell cycle regulation, apoptosis, differentiation, and stress response. They have been shown to function as estrogen receptor co-repressors, and there is evidence for a role in breast tumorigenesis. To identify their endogenous target genes in MCF-7 breast cancer cells, we utilized gene expression array analysis, which was set up in a two-by-four design, with vehicle and estrogen treatment, and control, SAFB1, SAFB2, and SAFB1/SAFB2 siRNA as variables. Using custom chips containing 1.5 kb upstream regulatory region, we identified 541 SAFB1/SAFB2 binding sites in promoters of known genes, with significant enrichment on chromosome 1 and 6. Gene expression analysis revealed that the majority of target genes were induced in the absence of SAFB1 or SAFB2, and less were repressed. In contrast to SAFB2, which shared most of its target genes with SAFB1, SAFB1 had many unique target genes, most of them involved in regulation of the immune system. A subsequent analysis of the estrogen treatment group revealed that twelve percent of estrogen-regulated genes were dependent on SAFB1, with the majority being estrogen-repressed genes. These were primarily genes involved in apoptosis, such as BBC3, NEDD9, and OPG. Thus, this study confirms SAFB1/SAFB2s primary role as co-repressors, and also uncovers a previously unknown role for SAFB1 in regulation of immune genes, and in estrogen-mediated repression of genes.
Publication Title
SAFB1 mediates repression of immune regulators and apoptotic genes in breast cancer cells.
Sample Metadata Fields
Cell line, Treatment
View Samples- Homo sapiens
- 13 Downloadable Samples
Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
To investigate molecular mechanisms of resistance, we used two different in vivo xenograft models of estrogen receptor-positive (ER+) breast cancer, with or without HER2 over-expression (MCF7/HER2-18 and MCF7 wt, respectively). Mice with established tumors were assigned to the following treatment groups: continued estrogen supplementation (E2), estrogen deprivation (ED), ED plus tamoxifen (Tam), all with or without the EGFR tyrosine kinase inhibitor gefinitinib (G). Another group received ED plus the antiestrogen fulvestrant (MCF7 wt only). Tumors with acquired or de novo resistance to these endocrine therapies were profiled for mRNA expression using Affymetrix Genechip arrays.
Publication Title
Development of resistance to targeted therapies transforms the clinically associated molecular profile subtype of breast tumor xenografts.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 7 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
In order to help determine the genes involved in resistance of breast cancer to endocrine therapy, we compared global gene expression profiles of tamoxifen-resistant MCF-7 WT xenograft tumors with E2-supplemented tumors.
Publication Title
Tamoxifen resistance in breast tumors is driven by growth factor receptor signaling with repression of classic estrogen receptor genomic function.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 102 Downloadable Samples
- Affymetrix Human Genome U133A Array (hgu133a)
Description
Obesity is thought to contribute to worse disease outcome in breast cancer as a result of increased levels of adipocyte-secreted endocrine factors, insulin, and insulin-like growth factors (IGFs) that accelerate tumor cell proliferation and impair treatment response. We examined the effects of patient obesity on primary breast tumor gene expression, by profiling transcription of a set of tumors for which the patients body mass index (BMI) was ascertained. Sample profiles were stratified according to patients obesity phenotype defined as normal (BMI <25), overweight (BMI 25-29.9), or obese (BMI>30). Widespread alterations in gene expression were evident in breast tumors from obese patients as compared to tumors from other patients, allowing us to define an obesity-associated cancer transcriptional signature of 662 genes.
Publication Title
A gene transcription signature of obesity in breast cancer.
Sample Metadata Fields
Age, Disease, Disease stage, Race
View Samples- Mus musculus
- 8 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
A major component of the cardiac stress response is the simultaneous activation of several gene regulatory networks. Interestingly, the transcriptional regulator steroid receptor coactivator-2, SRC-2 is often decreased during cardiac failure in humans. We postulated that SRC-2 suppression plays a mechanistic role in the stress response and that SRC-2 activity is an important regulator of the adult heart gene expression profile. Genome-wide microarray analysis, confirmed with targeted gene expression analyses revealed that genetic ablation of SRC-2 activates the fetal gene program in adult mice as manifested by shifts in expression of a) metabolic and b) sarcomeric genes, as well as associated modulating transcription factors. While these gene expression changes were not accompanied by changes in left ventricular weight or cardiac function, imposition of transverse aortic constriction (TAC) predisposed SRC-2 knockout (KO) mice to stress-induced cardiac dysfunction. In addition, SRC-2 KO mice lacked the normal ventricular hypertrophic response as indicated through heart weight, left ventricular wall thickness, and blunted molecular signaling known to activate hypertrophy. Our results indicate that SRC-2 is involved in maintenance of the steady-state adult heart transcriptional profile, with its ablation inducing transcriptional changes that mimic a stressed heart. These results further suggest that SRC-2 deletion interferes with the timing and integration needed to respond efficiently to stress through disruption of metabolic and sarcomeric gene expression and hypertrophic signaling, the three key stress responsive pathways.
Publication Title
SRC-2 coactivator deficiency decreases functional reserve in response to pressure overload of mouse heart.
Sample Metadata Fields
Sex, Specimen part
View Samples