Ontology highlight
ABSTRACT:
PROVIDER: PRJNA236645 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Molecular diversity of breast cancers at the time of endocrine resistance [microRNA]
| PRJNA236649 | ENA
Project description:Molecular diversity of breast cancers at the time of endocrine resistance [mRNA]
| PRJNA236605 | ENA
Project description:The estrogen receptor alpha (ERa) drives the growth of two-thirds of all breast cancers. Endocrine therapy impinges on estrogen-induced ERa activation to block tumor growth. However, half of ERa-positive breast cancers are tolerant or acquire endocrine therapy resistance. Here we demonstrate that breast cancer cells undergo genome-wide reprogramming of their chromatin landscape, defined by epigenomic maps and chromatin openness, as they acquire resistance to endocrine therapy. This reveals a role for the Notch pathway while excluding classical ERa signaling. In agreement, blocking Notch signaling, using gamma-secretase inhibitors, or targeting its downstream gene PBX1 abrogates growth of endocrine therapy-resistant breast cancer cells. Moreover Notch signaling through PBX1 directs a transcriptional program predictive of tumor outcome and endocrine therapy response. Comparing histone modifications (H3K4me2 and H3K36me3), chromatin openness (FAIRE) and PBX1 binding between endocrine therapy sensitive MCF7 and resistant MCF7-LTED cells.
2013-05-01 | E-GEOD-37323 | biostudies-arrayexpress
Project description:Dataset containing micro-RNA expression profiles of breast cancers at the time of endocrine resistance. It has been used to correlate micro-RNA and mRNA expressions and to identify two distinctive phenotypes with different expression of micro-RNA gens. Please note that the tumor samples are clinically quite homogeneous: all are post-menopausal ER+ve breast cancers, endocrine treated and growing on treatment. The main purpose of collecting these data was not to compare transcriptional profiles with clinical parameters, but rather to use the micro-RNA expression profiles of these clinically homogeneous tumours for (i) identifying intrinsic subgroups within endocrine resistance and (ii) for relating micro-RNA and mRNA expressions. However, the relevant clinical data was also provided as Series supplementary file (ClinicalData_AL28Jan2014.xlsx).
2014-12-01 | GSE54496 | GEO
Project description:The estrogen receptor alpha (ERa) drives the growth of two-thirds of all breast cancers. Endocrine therapy impinges on estrogen-induced ERa activation to block tumor growth. However, half of ERa-positive breast cancers are tolerant or acquire endocrine therapy resistance. Here we demonstrate that breast cancer cells undergo genome-wide reprogramming of their chromatin landscape, defined by epigenomic maps and chromatin openness, as they acquire resistance to endocrine therapy. This reveals a role for the Notch pathway while excluding classical ERa signaling. In agreement, blocking Notch signaling, using gamma-secretase inhibitors, or targeting its downstream gene PBX1 abrogates growth of endocrine therapy-resistant breast cancer cells. Moreover Notch signaling through PBX1 directs a transcriptional program predictive of tumor outcome and endocrine therapy response.
2013-05-01 | GSE37323 | GEO
Project description:Phenotypic plasticity has emerged as an important mechanism of therapy resistance in cancers, yet the underlying molecular mechanisms remain unclear. Using an established breast cancer cellular model for endocrine resistance, we show that hormone resistance is associated with enhanced phenotypic plasticity, indicated by a general downregulation of luminal/epithelial differentiation markers and upregulation of basal/mesenchymal invasive markers. Our extensive omics studies, including GRO-seq on enhancer landscapes, demonstrate that the global enhancer gain/loss reprogramming driven by the differential interactions between ER-alpha and other oncogenic transcription factors (TFs), predominantly GATA3 and AP1, profoundly alters breast cancer transcriptional programs. Our functional studies in multiple biological systems support a coordinate role of GATA3 and AP1 in enhancer reprogramming that drives phenotypic plasticity to achieve endocrine resistance or cancer invasive progression. Thus, changes in TF-TF and TF-enhancer interactions can lead to genome-wide enhancer reprogramming, resulting in transcriptional dysregulations that promote plasticity and cancer therapy-resistance progression
2019-05-24 | MSV000083857 | MassIVE
Project description:Dataset containing whole-genome expression profiles of breast cancers at the time of endocrine resistance. It has been used to identify five distinctive phenotypes with different expression of gene clusters associated with ER-signalling, stromal rearrangement and cytokine-signalling. Pathway-focused analysis suggested individual tumours with active ER-signalling (24/55, 44%), PIK3CA-signalling (18/55, 32%), RAS (12/55, 22%) and MYC-signalling (11/55, 20%). 3 or 4 of the above pathways were simultaneously active in 6/55 (11%) cases. Results provide important information about prevalence of different mechanisms of endocrine resistance in clinical samples of breast cancer. Please note that the tumor samples are clinically quite homogeneous: all are post-menopausal ER+ve breast cancers, endocrine treated and growing on treatment. The main purpose of collecting these data was not to compare transcriptional profiles with clinical parameters, but rather to use the transcriptional profiles of these clinically homogeneous tumours for identifying intrinsic subgroups within endocrine resistance. However, the relevant clinical data was also provided as Series supplementary file (ClinicalData_AL28Jan2014.xlsx).
2014-12-01 | GSE54479 | GEO
Project description:Estrogen receptor alpha (ERα) expression in breast cancer is predictive of response to endocrine therapy, however resistance is common in ERα-positive tumors that over-express the growth factor receptor ERBB2. Even in the absence of estrogen, ERα can be activated by growth factors including the epidermal growth factor (EGF). EGF induces a transcriptional program distinct from estrogen, however the mechanism of the stimulus-specific response is unknown. Here we show that the EGF-induced ERα genomic targets, its cistrome, are distinct from those induced by estrogen in a process dependent on the transcription factor AP-1. The EGF-induced ERα cistrome specifically regulates genes found over-expressed in ERBB2-positive human breast cancers. This provides a potential molecular explanation for the endocrine therapy resistance seen in ERα-positive breast cancers that over-express ERBB2. These results suggest a central role for ERα in hormone-refractory breast tumors dependent on growth factor pathway activation and favors the development of therapeutic strategies completely antagonizing ERα as opposed to blocking its estrogen responsiveness alone.
2010-12-29 | GSE26081 | GEO
Project description:Molecular changes in lobular breast cancers in response to endocrine therapy
| PRJNA239428 | ENA
Project description: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. This role is exploited both at the DNA methylation level, with activation of oncogenes and silencing of tumor suppressor genes, and at the histone modification level, with changes in chromatin accessibility. DNA methylation exerts its role in resistance both by targeting the ER itself, by inducing promoter methylation, and genome wide, by changing the methylation levels of estrogen response elements. To better understand resistance acquisition in an in vitro setting, researchers developed cellular models of endocrine therapy resistance. The prevalent strategy to identify mechanisms of resistance development and novel targets involved in the process has been to study differences between resistant and sensitive cells. Here, we performed time-resolved DNA methylation profiling of development of resistance to tamoxifen treatment and to estrogen deprivation in the T47D luminal A breast cancer cell line with the aim to identify novel drivers.
2020-07-17 | GSE154626 | GEO