GEO DataSets

(Submitter supplied) To investigate response or resistance to endocrine therapy, mice with targeted over-expression of Esr1 or CYP19A1 to mammary epithelial cells were employed, representing two direct pathophysiological interventions in estrogen pathway signaling. Both Esr1 and CYP19A1 over-expressing mice responded to letrozole with reduced HAN prevalence and decreased mammary epithelial cell proliferation. CYP19A1 over-expressing mice were tamoxifen-sensitive but Esr1 over-expressing mice were tamoxifen-resistant. more...

Organism:

Mus musculus

Type:

Expression profiling by high throughput sequencing

Platform:

GPL13112

17 Samples

Download data: TXT

(Submitter supplied) Hyperactivation of phosphatidylinositol-3 kinase (PI3K) promotes escape from hormone dependence in estrogen receptor-positive breast cancer. A significant fraction of breast cancers exhibit de novo or acquired resistance to estrogen deprivation. We used gene expression microarrays to identify genes and pathways that are commonly dysregulated in ER+ cell lines with acquired hormone-independent growth. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL570

24 Samples

Download data: CEL, CHP

(Submitter supplied) Acquired resistance to endocrine therapy occurs with high frequency in patients with luminal breast cancer (LBC). We report here the establishment of four patient-derived xenograft models of LBC with acquired resistance in vivo to tamoxifen and estrogen deprivation.

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL11532

30 Samples

Download data: CEL

(Submitter supplied) MCF-7aro cells were used to generate a cell culture model system that is resistant to 3 aromatase inhibitors (AIs), letrozole, anastrozole and exemestane. For comparison, the MCF-7aro cells were also used to generate the tamoxifen-resistant cells as well as long-term estrogen deprived, LTEDaro. Affymetrix microarray analysis was performed to determine changes in gene expression that are unique to AI-resistance. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL571

42 Samples

Download data: CEL

(Submitter supplied) Anti-estrogens and aromatase inhibitors are important drugs in the treatment of estrogen-dependent breast cancer. In order to investigate the effects of these drugs on gene expression in breast cancer cells, we treated estrogen receptor-positive MCF-7 cells, stably transfected with the aromatase gene (known as MCF-7aro cells), with testosterone, 17β-estradiol, two aromatase inhibitors (letrozole and anastrozole), and an anti-estrogen (tamoxifen). more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Dataset:

GDS1873

Platform:

GPL96

18 Samples

Download data: CEL, EXP

Analysis of estrogen receptor positive, aromatase transfected MCF-7 cells after treatment with an antiestrogen (AE) or an aromatase inhibitor (AI). AEs and AIs are used to treat estrogen-dependent breast cancer. Cells also treated with androgen which is converted to estrogen by aromatase.

Organism:

Homo sapiens

Type:

Expression profiling by array, count, 6 agent, 4 other sets

Platform:

GPL96

Series:

GSE2225

18 Samples

Download data: CEL, EXP

(Submitter supplied) Resistance to endocrine therapy agents has presented a clinical obstacle in the treatment of hormone-dependent breast cancer. Our laboratory has initiated a study of microRNA regulation of signaling pathways that may result in breast cancer progression on aromatase inhibitors (AI). Microarray analysis of microRNA expression identified 115 significantly regulated microRNAs, of which 49 microRNAs were believed to be hormone-responsive. more...

Organism:

Homo sapiens

Type:

Non-coding RNA profiling by array

Platform:

GPL9081

23 Samples

Download data: TXT

(Submitter supplied) The overarching goal of this study was to explore the antitumor activity of Z-endoxifen, a tamoxifen metabolite, with first-line endocrine therapies tamoxifen and letrozole in the letrozole-sensitive MCF7 aromatase expressing model (MCF7AC1), and with second-line endocrine therapies including tamoxifen, fulvestrant, exemestane, and exemestane plus everolimus, in letrozole-resistant MCF7 model (MCF7LR) in vivo. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL570

11 Samples

Download data: CEL

(Submitter supplied) To identify novel therapeutic opportunities for patients with acquired resistance to endocrine treatments in breast cancer, we applied a high-throughput drug screen. The IC50 values were determined for MCF7 and MCF7-LTED cells.

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL13667

4 Samples

Download data: CEL

(Submitter supplied) Tamoxifen is the most widely administered adjuvant first-line hormone therapy for Estrogen receptor α (ERα) positive breast cancer patients. However, one from three patients will develop resistance, while the underlying molecular mechanisms are currently unclear. Recent studies reported that abnormal expression of miRNAs played a role in cancer progress. To study the potential function of miRNAs in tamoxifen resistance, Affymetrix GeneChip® miRNA 3.0 microarray was employed to identify differentially expressed miRNAs between tamoxifen sensitive MCF7 parent (MCF7-Pa) cells and induced resistant (MCF7-Re) cells.

Organism:

Homo sapiens; synthetic construct

Type:

Non-coding RNA profiling by array

Platform:

GPL16384

2 Samples

Download data: CEL

(Submitter supplied) Why breast cancers become resistant to tamoxifen despite continued expression of the estrogen receptor alpha (ERα) and what factors are responsible for high HER2 expression in these tumors remains an enigma. HOXB7 ChIP analysis followed by validation showed that HOXB7 physically interacts with ERα, and that the HOXB7-ERα complex enhances transcription of many ERα target genes including HER2. Investigating strategies for controlling HOXB7, our studies revealed that MYC, stabilized via phosphorylation mediated by EGFR-HER2 signaling, inhibits transcription of miRNA-196a, a HOXB7 repressor. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL10558

4 Samples

Download data: TXT

(Submitter supplied) In the present investigation, we have exploited the opportunity provided by neoadjuvant treatment of a group of postmenopausal women with large operable or locally advanced breast cancer (in which therapy is given with the primary tumour remaining within the breast) to take sequential biopsies of the same cancers before and after 10-14 days or 90 days treatment with letrozole. RNA extracted from the biopsies has been subjected to Affymetrix microarray analysis and the data from paired biopsies interrogated to discover genes whose expression is most influenced by oestrogen deprivation. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL96

176 Samples

Download data: CEL

(Submitter supplied) In the present investigation, we have exploited the opportunity provided by neoadjuvant treatment of a group of postmenopausal women with large operable or locally advanced breast cancer (in which therapy is given with the primary tumour remaining within the breast) to take sequential biopsies of the same cancers before and after 10-14 days treatment with letrozole. RNA extracted from the biopsies has been subjected to Affymetrix microarray analysis and the data from paired biopsies interrogated to discover genes whose expression is most influenced by oestrogen deprivation. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Dataset:

GDS3116

Platform:

GPL96

116 Samples

Download data: CEL

Analysis of breast cancer tumors following treatment with letrozole for 14 days. The aromatase inhibitor letrozole is an anti-estrogen drug used to treat postmenopausal women with breast cancer. Results provide insight into the molecular mechanism of action of letrozole in breast cancer.

Organism:

Homo sapiens

Type:

Expression profiling by array, count, 2 agent, 58 individual sets

Platform:

GPL96

Series:

GSE5462

116 Samples

Download data: CEL

(Submitter supplied) Tamoxifen is the most widely prescribed anti-estrogen treatment for patients with ER-positive breast cancer. However, there is still a need for biomarkers that reliably predict endocrine sensitivity in breast cancers and these may well be expressed in a dynamic manner. In this study we assessed gene expression changes at multiple time points (days 1, 2, 4, 7, 14) after tamoxifen treatment in the ER-positive ZR-75-1 xenograft model that displays significant changes in apoptosis, proliferation and angiogenesis within 2 days of therapy. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL506

32 Samples

Download data: TXT

(Submitter supplied) Gene expression profiling of invasive breast cancer events from the tamoxifen prevention trial validates low estrogen receptor mRNA level as the main determinant of tamoxifen resistance in estrogen receptor positive breast cancer. In NSABP Breast Cancer Prevention Trial (BCPT), tamoxifen reduced the incidence of estrogen receptor (ER) positive tumors but not estrogen receptor negative breast cancer. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL6480

108 Samples

Download data: TXT

(Submitter supplied) The tumor suppressor gene p53 is frequently mutated in human breast cancer and is a marker for poor prognosis and resistance to chemotherapy. Transplantation of p53-null mouse mammary epithelium into syngeneic wild-type mice leads to normal mammary gland development followed by spontaneous mammary tumors that recapitulate many of the phenotypic, molecular, and genetic features of human breast cancer. more...

Organism:

Mus musculus

Type:

Expression profiling by array

Platform:

GPL6096

6 Samples

Download data: CEL

(Submitter supplied) Five years of tamoxifen reduces breast cancer risk by nearly 50% but is associated with significant side-effects and toxicities. A better understanding of the direct and indirect effects of tamoxifen in benign breast tissue could elucidate new mechanisms of breast carcinogenesis, suggest novel chemoprevention targets, and provide relevant early response biomarkers for Phase II prevention trials. Seventy-three women at increased risk for breast cancer were randomized to tamoxifen (20 mg daily) or placebo for three months. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL13376

80 Samples

Download data: TXT

(Submitter supplied) Genomic analysis has recently identified multiple ESR1 gene translocations in estrogen receptor-alpha positive (ERα+) metastatic breast cancer (MBC) that encode chimeric proteins whereby the ESR1 ligand binding domain (LBD) is replaced by C-terminal sequences from many different gene partners. Here we functionally screened 15 ESR1 fusions and identified 10 that promoted estradiol-independent cell growth, motility, invasion, EMT and resistance to fulvestrant. more...

Organism:

Homo sapiens

Type:

Expression profiling by high throughput sequencing

Platform:

GPL24676

42 Samples

Download data: RESULTS

(Submitter supplied) We report the single cell sequencing data from subcutaneous adipose tissue CD29+ stromal cells (mesenchymal stem cells). Subcutaneous adipose tissue was collected from a mouse model of obesity and breast cancer anti-estrogen therapy. Lean and obese mice were ovariectomized, supplemented with estradiol, then maintained on estradiol, given tamoxifen, or estradiol was withdrawn for 7 weeks.

Organism:

Mus musculus

Type:

Expression profiling by high throughput sequencing

Platform:

GPL24247

6 Samples

Download data: TSV