GEO DataSets

(Submitter supplied) 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). more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL570

65 Samples

Download data: CEL

(Submitter supplied) 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). more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL570

14 Samples

Download data: CEL, XLS

(Submitter supplied) 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). more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL570

51 Samples

Download data: CEL, TXT

(Submitter supplied) 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. Keywords: two group comparison

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL570

7 Samples

Download data: CEL

(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) Activation of the PI3K pathway in estrogen receptor α (ER)-positive (+) breast cancer is associated with reduced ER expression and activity, luminal B subtype, and poor outcome. PTEN is a negative regulator of the PI3K pathway typically lost in ER-negative (-) breast cancer. To clarify the effect of PTEN down-regulation on the response of ER+/HER2- breast cancer to endocrine therapy, we established reduced PTEN cell models using inducible knockdown. more...

Organism:

Homo sapiens

Type:

Expression profiling by high throughput sequencing

Platform:

GPL9052

2 Samples

Download data: FPKM_TRACKING

(Submitter supplied) Phosphoinositide-3-kinase/protein-kinaseB/mammalian target of rapamycin (PI3K/AKT/mTOR) signalling plays an important role in breast cancer (BC). Its interaction with estrogen receptor (ER) signalling becomes more complex and inter-dependent with acquired endocrine resistance. Targeting mTOR combined with endocrine therapy has shown clinical utility, however, a negative feedback-loop exists downstream of PI3K/AKT/mTOR. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL10558

12 Samples

Download data: TXT

(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) Endocrine therapy is the most used treatment for hormone receptor positive breast cancers. Despite the clear benefit of endocrine therapy for patients with ER+ breast cancer, resistance to treatment is a critical clinical issue affecting a large number of patients. While many studies have shown that genetics is an important factor in therapy resistance, recent publications have also reported that epigenetics might play a major role in the acquisition of resistance to endocrine therapies. more...

Organism:

Homo sapiens

Type:

Methylation profiling by genome tiling array

Platform:

GPL21145

40 Samples

Download data: TXT

(Submitter supplied) Full title: Expression data from antisense miRNA-221/222 (si221/222) and control inhibitor (GFP) treated fulvestrant-resistant breast cancer cells The expression of miR-221/222 were found to be upregulated in fulvestrant resistant breast cancer cells MCF7-FR compared to its drug-sensitive counterpart MCF7. To investigate the role of miR-221/222 in acquired resistance to fulvestrant, we lowered the level of miR-221/222 in MCF7-FR cells using miRNA inhibitors (antagomirs), and compared gene expression profiles before and after treatment.

Organism:

Homo sapiens

Type:

Expression profiling by array

Dataset:

GDS4054

Platform:

GPL570

9 Samples

Download data: CEL

Analysis of fulvestrant-resistant MCF7 cells transfected with antisense miRNA inhibitors targeting miR-221 and miR-222. miR-221/222 knockdown inhibits cell proliferation in fulvestrant-resistant MCF7-F cells. Results provide insight into the role of miR-221/222 in acquired resistance to fulvestrant.

Organism:

Homo sapiens

Type:

Expression profiling by array, transformed count, 3 genotype/variation sets

Platform:

GPL570

Series:

GSE19777

9 Samples

Download data: CEL

(Submitter supplied) Gene expression analysis of MEL-18-silenced MCF7 cell lines. MEL-18 is a component of the polycomb repressive complex (PRC)-1, which is a critical epigenetic modulator of stem cell regulation and normal and cancerous development. Accumulating studies have suggested that MEL-18 might act as a tumor suppressor in several human tumors, including breast cancer. Results provide insight into the functional role of MEL-18 in estrogen-dependent breast cancer.

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL10558

4 Samples

Download data: TXT

(Submitter supplied) A significant fraction of breast cancers exhibit de novo or acquired resistance to estrogen deprivation. A kinome-wide siRNA screen identified a role for Insulin Receptor (InsR) in the hormone-independent growth of ER+ breast cancer cells We used gene expression microarrays to identify genes and pathways that are altered by insulin stimulation of ER+ MCF-7 human breast cancer cells.

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL13158

9 Samples

Download data: CEL, CHP

(Submitter supplied) Estrogen receptor positive (ER+) breast cancers that develop resistance to therapies that target the ER are the most common cause of breast cancer death. Beyond mutations in ER, which occur in 25-30% of patients treated with aromatase inhibitors (AIs), our understanding of clinical mechanisms of resistance to ER-directed therapies remains incomplete. We identified activating HER2 mutations in metastatic biopsies from eight patients with ER+ metastatic breast cancer who had developed resistance to ER-directed agents, including AIs, tamoxifen, and fulvestrant. more...

Organism:

Homo sapiens

Type:

Expression profiling by high throughput sequencing

Platform:

GPL18573

864 Samples

Download data: TXT

(Submitter supplied) Under conditions of hormonal adjuvant treatment the estrogen receptor apoprotein supports breast cancer cell cycling through the retinoic acid receptor α1 apoprotein. Basal proliferation persisted in estrogen-sensitive breast cancer cells grown in hormone depleted conditioned media without or with 4-hydroxytamoxifen (OH-Tam). Downregulating ER using siRNA inhibited basal proliferation by promoting cell cycle arrest. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Dataset:

GDS4065

Platform:

GPL570

12 Samples

Download data: CEL

Analysis of MCF7 cells transfected with control siRNA, estrogen receptor α (ER) siRNA or retinoic acid receptor α (RARα) siRNA. Basal proliferation of MCF7 cells was diminished by knocking down ER or RARα. Results provided insight into the molecular basis of basal proliferation.

Organism:

Homo sapiens

Type:

Expression profiling by array, count, 2 agent, 3 dose, 3 genotype/variation sets

Platform:

GPL570

Series:

GSE26298

12 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) Aromatase inhibitors are first-line postmenopausal agents for estrogen receptor alpha (ERa)-positive breast cancer. However, there is considerable response heterogeneity and women frequently relapse. Estrogen deprivation does not completely arrest ERa activity, and transactivation of the unliganded receptor may continue through cross-talk with growth factor pathways. In contrast with aromatase inhibitors, the selective ER downregulator fulvestrant also abrogates ligand-independent ERa activity. more...

Organism:

Homo sapiens

Type:

Expression profiling by array

Platform:

GPL6884

76 Samples

Download data: TXT

(Submitter supplied) The aim of the study is to understand the role of the transcription factor PAX2 in estrogen receptor positive breast cancer cell line by using ChIP-seq. MCF-7-PAX2 stable cells were cultured in full media and treated with doxycycline (50ng/ml) for 16 hours to induce overexpression of PAX2-HA protein. Then cells were treated with 4-OH-tamoxifen (1μM) for 6 hours. All 3 treatments (Veh, Dox, DoxTam) were performed in duplicates. more...

Organism:

Homo sapiens

Type:

Genome binding/occupancy profiling by high throughput sequencing

Platforms:

GPL18573 GPL9052

7 Samples

Download data: NARROWPEAK

(Submitter supplied) The aim of the study is to understand the role of the transcription factor PAX2 in estrogen receptor positive breast cancer cell line by using GRO-seq. MCF-7-PAX2 stable cells were cultured in full media and treated with doxycycline (50ng/ml) for 16 hours to induce overexpression of PAX2. Then cells were treated with 4-OH-tamoxifen (1μM) for 6 hours. All 4 treatments (Veh, Tam, Dox, DoxTam) were performed in duplicates. more...

Organism:

Homo sapiens

Type:

Expression profiling by high throughput sequencing

Platform:

GPL11154

8 Samples

Download data: TXT