Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA305002 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Split Ends (SPEN) is a transcriptional coregulator that have formerly identified as a tumour suppressor gene in ER-positive breast cancers. However, ER-positive breast cancers are diagnosed at similar frequencies in pre- and post-menopausal women who show significantly different circulating hormone levels. This therefore raises the possibility that SPEN functions under hormone-depleted settings may contrast with its roles in the presence of hormones. We therefore attempted to explore the cellular functions regulated by SPEN under hormone-depleted settings using a previously established model with T47D cells stably transfected with a control vector (non-target) or SPEN-expressing vector. In particular, we attempted to investigate the hormone-independent transcriptional program regulated by SPEN in breast cancer. To achieve this, we have treated previously established T47D cells stably transfected with a control vector (non-target) or SPEN-expressing vector. These cells were allowed to grow in hormone-depleted conditions for 4 days. To minimize external biases introduced by hormone depletion or any transcriptional contribution from the estrogen receptor (ER), we also performed gene expression profiling analyses on the same cells but stimulated with an estrogen receptor (ER) agonist (Estradiol) or antagonist (Tamoxifen).
2017-08-15 | E-MTAB-4975 | biostudies-arrayexpress
Project description:Estrogen receptor positive breast cancer is the most prevalent form of breast cancer. Although a number of available drugs are highly effective at blocking estrogen mediated receptor activity, thousands of patients die every year from ER positive breast cancers because the disease progresses to a stage at which these drugs are no longer effective. Thus, it is crucial to establish a comprehensive understanding of the biology of the estrogen receptor (ER) in ER:positive breast cancers that progress despite hormone therapy, a gap in knowledge that remains a serious impediment to successful treatment of patients with ER positive breast cancer. A key question that must be answered is how the estrogen receptor retains the capacity to activate transcription in the absence or near absence of estrogen. We have found a partial answer to this question upon investigating the effect of amplification and overexpression of Wolf Hirschhorn Syndrome Candidate 1:Like 1 (WHSC1L1), a gene that is amplified in 15% of breast cancers that codes for a histone:lysine methyltransferase. WHSC1L1 lies in the 8p11:p12 amplicon, a region of gene amplification that is strongly associated with breast cancer. In this study, we performed shRNA knockdown of the catalytically inactive short isoform of WHSC1L1 in SUM44PE breast cancer cells and found that expression of the short isoform of WHSC1L1 is necessary for expression of the estrogen receptor in this highly ER:positive cell line. In addition, we found that the estrogen receptor binds chromatin extensively in the absence of exogenous estrogen, including several actively transcribed canonical ER target genes, indicating that estrogen receptor signaling is active in SUM44 cells in estrogen free conditions. These findings represent a novel model for ER biology in luminal B breast cancers harboring amplification of WHSC1L1 and provide insight into the mechanisms by which ER: positive breast cancers become unresponsive to SERMs or aromatase inhibitors.
2016-05-07 | E-MTAB-3739 | biostudies-arrayexpress
Project description:Hormone-dependent gene expression requires dynamic and coordinated epigenetic changes. Estrogen receptor-positive (ER+) breast cancer is particularly dependent upon extensive chromatin remodeling and changes in histone modifications for the induction of hormone-responsive gene expression. Our previous studies established an important role of bromodomain-containing protein-4 (BRD4) in promoting estrogen-regulated transcription and proliferation of ER+ breast cancer cells. Here, we investigated the association between genome-wide occupancy of histone H4 acetylation at lysine 12 (H4K12ac) and BRD4 in the context of estrogen-induced transcription. Similar to BRD4, we observed that H4K12ac occupancy increases near the transcription start sites (TSS) of estrogen-induced genes as well as at distal ERα binding sites in an estrogen-dependent manner. Interestingly, H4K12ac occupancy highly correlates with BRD4 binding and enhancer RNA production on ERα-positive enhancers. Consistent with an importance in estrogen-induced gene transcription, H4K12ac occupancy globally increased in ER-positive cells relative to ER-negative cells and these levels were further increased by estrogen treatment in an ERα-dependent manner. Together, these findings reveal a strong correlation between H4K12ac and BRD4 occupancy with estrogen-dependent gene transcription and further suggest that modulators of H4K12ac and BRD4 may serve as new therapeutic targets for hormone-dependent cancers. ChIP-seq profiles of H4K12ac in MCF7 cells treated with +/- estrogen treatment and MCF10A cells.
2015-05-02 | E-GEOD-65886 | biostudies-arrayexpress
Project description:Estrogens are an important regulator of breast cancer disease progression, and they function by binding the estrogen receptor-α (ERα) to regulate changes in gene expression. ERα is able to both activate and inhibit gene transcription in a gene-specific manner and do so by binding target DNA sequences and recruiting coactivators and corepressors which can modulate the chromatin environment. Silencing mediator of retinoic acid and thyroid hormone receptor (SMRT) is known to act as coactivator and corepressor of ERα in a gene-specific manner. We used a microarray analysis to examine the gene expression changes that occur when the coregulator SMRT is depleted from the ERα positive MCF-7 breast cancer cell line.
2014-06-21 | GSE57935 | GEO
Project description:Hormone therapy targeting estrogen receptor (ER) is the principal treatment for ER-positive breast cancers but many cancers develop resistance to anti-estrogens. Cyclin-dependent kinase 8 (CDK8) is a transcriptional regulator of several oncogenic pathways. Expression levels of CDK8 and ERα are inversely correlated in breast cancers suggesting a functional association between CDK8 and ER. CDK8 inhibition by selective small-molecule inhibitors, by shRNA knockdown or by CRISPR-Cas9 knockout suppressed estrogen-induced transcription, with no significant effects on ERα protein expression or phosphorylation. CDK8 inhibition also abrogated the mitogenic effect of estrogen on ER-positive breast cancer cells and potentiated growth inhibition by the ER antagonist fulvestrant. In vivo, administration of a CDK8 inhibitor suppressed ER-positive breast cancer xenograft growth and augmented the effects of fulvestrant with no apparent toxicity. CDK8 inhibitors also suppressed the development of estrogen independence in ER-positive breast cancer cells. These results identify CDK8 as a novel drug target for breast cancer therapy.
2017-02-14 | GSE93193 | GEO
Project description:Poly (ADP-ribose) polymerase-1 (PARP-1), a multifunctional chromatin-modulating protein, has gained considerable attention as a target for therapeutic inhibitors in breast cancers. Accumulating evidence suggests a pathological role for PARP-1 in breast cancer through its effects on the transcription of tumor-related genes. Here we report the role of PARP-1 in estrogen-dependent transcription in estrogen receptor alpha (ERα)-positive breast cancers. Global nuclear run-on and sequencing (GRO-seq) analyses suggest that PARP-1 controls the expression of estrogen-regulated genes in ER-positive (ER+) MCF-7 breast cancer cells. Further, ChIP-seq analyses revealed that PARP-1 directly regulates the ligand-dependent binding of ERa and FoxA1 to a subset of its genomic binding sites. Finally, we uncovered that the expression levels of the PARP-1 and estrogen coregulated gene set are enriched in luminal molecular-subtype of breast tumors and high PARP-1 expression in ER+ cases correlates with poor survival. Additionally, treatment with PARP-1 selective inhibitors showed attenuated estrogen-dependent growth of ER+ breast cancer cells. Taken together, the current study suggests that PARP-1 regulates critical molecular pathways that underlie proliferation of ER+ breast cancer cells.
2021-10-13 | GSE166168 | GEO
Project description:Hormone-dependent gene expression requires dynamic and coordinated epigenetic changes. Estrogen receptor-positive (ER+) breast cancer is particularly dependent upon extensive chromatin remodeling and changes in histone modifications for the induction of hormone-responsive gene expression. Our previous studies established an important role of bromodomain-containing protein-4 (BRD4) in promoting estrogen-regulated transcription and proliferation of ER+ breast cancer cells. Here, we investigated the association between genome-wide occupancy of histone H4 acetylation at lysine 12 (H4K12ac) and BRD4 in the context of estrogen-induced transcription. Similar to BRD4, we observed that H4K12ac occupancy increases near the transcription start sites (TSS) of estrogen-induced genes as well as at distal ERα binding sites in an estrogen-dependent manner. Interestingly, H4K12ac occupancy highly correlates with BRD4 binding and enhancer RNA production on ERα-positive enhancers. Consistent with an importance in estrogen-induced gene transcription, H4K12ac occupancy globally increased in ER-positive cells relative to ER-negative cells and these levels were further increased by estrogen treatment in an ERα-dependent manner. Together, these findings reveal a strong correlation between H4K12ac and BRD4 occupancy with estrogen-dependent gene transcription and further suggest that modulators of H4K12ac and BRD4 may serve as new therapeutic targets for hormone-dependent cancers.
2015-05-02 | GSE65886 | GEO
Project description:Estrogens are an important regulator of breast cancer disease progression, and they function by binding the estrogen receptor--alpha (ER-alpha) to regulate changes in gene expression. ER-alpha is able to both activate and inhibit gene transcription in a gene-specific manner and do so by binding target DNA sequences and recruiting coactivators and corepressors which can modulate the chromatin environment. Silencing mediator of retinoic acid and thyroid hormone receptor (SMRT) is known to act as coactivator and corepressor of ER-alpha in a gene-specific manner. We used a microarray analysis to examine the gene expression changes that occur when the coregulator SMRT is depleted from the ER-alpha positive MCF-7 breast cancer cell line. We sought to determine the genes that are regulated by depletion of the coregulator SMRT using Affymetrix Human Gene 1.0 ST Array. To this end, we transfected MCF-7 cells with control siRNA or SMRT-targeting siRNA for 48 h and treated for an additional 4 or 24 h with vehicle (0.1% EtOH) or 1 nM estradiol (E2). A total of 24 samples were analyzed, separated into eight groups each with three experimental replicates in each group, siControl-Veh 4 h, siControl -E2 4 h, siSMRT-Veh 4 h, siSMRT-E2 4 h, siControl-Veh 24 h, siControl-E2 24 h, siSMRT-Veh 24 h, siSMRT-E2 24 h.
2014-06-21 | E-GEOD-57935 | biostudies-arrayexpress
Project description:Estrogen-regulated genes predict survival in estrogen receptor and/or progesterone receptor-positive breast cancers
| PRJNA92235 | ENA
Project description:Poly (ADP-ribose) polymerase-1 (PARP-1), a multifunctional chromatin-modulating protein, has gained considerable attention as a target for therapeutic inhibitors in breast cancers. Accumulating evidence suggests a pathological role for PARP-1 in breast cancer through its effects on the transcription of tumor-related genes. Here we report the role of PARP-1 in estrogen-dependent transcription in estrogen receptor alpha (ERα)-positive breast cancers. Global nuclear run-on and sequencing (GRO-seq) and RNA-seq analyses suggest that PARP-1 controls the expression of estrogen-regulated genes in ER-positive (ER+) MCF-7 breast cancer cells. Further, ChIP-seq analyses revealed that PARP-1 directly regulates the ligand-dependent binding of ERa and FoxA1 to a subset of its genomic binding sites. Finally, we uncovered that the expression levels of the PARP-1 and estrogen coregulated gene set are enriched in luminal molecular-subtype of breast tumors and high PARP-1 expression in ER+ cases correlates with poor survival. Additionally, treatment with PARP-1 selective inhibitors showed attenuated estrogen-dependent growth of ER+ breast cancer cells. Taken together, the current study suggests that PARP-1 regulates critical molecular pathways that underlie proliferation of ER+ breast cancer cells.
2021-10-13 | GSE173976 | GEO