Project description:Estrogens stimulate hypertrophy and hyperplasia in the uterus and exert their activity through estrogen receptor α (ERα). A uterine epithelial ERα conditional knockout mouse model (Wnt7aCre+;Esr1f/f or cKO) demonstrated that ERα in the epithelial cells was dispensable for an early uterine proliferative response to 17β-estradiol (E2), but required for subsequent uterine biological responses. We compared the gene expression profile in the uterus after E2 treatment in the cKO samples with WT samples. We found that approximately 25% of the genes differentially expressed at 2 h were epithelial ERα independent, as they were preserved in the cKO, indicating they are mediated from the stroma and sufficient to promote initial proliferative responses. However, more than 90% of the differentially expressed transcripts at 24 h were absent in the cKO, indicating the majority of later transcriptional regulation required epithelial ERα and suggesting the loss of regulation of these later transcripts results in the blunted growth response 3 days after treatment. These transcription profiles correlate with our previous biological responses, in which the initial proliferative response is independent of epithelial ERα but dependent on stromal ERα, yet epithelial ERα is essential for subsequent tissue responsiveness. These analyses are now allowing for in vivo determination of the cell specific actions of ERα in the female reproductive tract.
Project description:At birth, all female mice, including those that either lack estrogen receptor α (ERα-knockout) or that express mutated forms of ERα (AF2ERKI), have a hypoplastic uterus. However, uterine growth and development that normally accompanies pubertal maturation does not occur in ERα-knockout or AF2ERKI mice, indicating ERα mediated estrogen signaling is essential for this process. Mice that lack Cyp19 (aromatase, ArKO mice), an enzyme critical for estrogen (E2) synthesis, are unable to make E2, and lack pubertal uterine development. A single injection of E2 into ovariectomized adult (10 weeks old) females normally results in uterine epithelial cell proliferation, however, we observe that, although ERα is present in the ArKO uterine cells, no proliferative response is seen. We assessed the impact of exposing ArKO mice to E2 during pubertal and post-pubertal windows and observed that E2 exposed ArKO mice acquired growth responsiveness. Analysis of differential gene expression between unexposed ArKO samples and samples from animals exhibiting the ability to mount an E2-induced uterine growth response (WT or E2 exposed ArKO) revealed activation of EZH2 and HAND2 signaling and inhibition of GLI1 responses. EZH2 and HAND2 are known inhibit uterine growth, and GLI1 is involved in IHH signaling, which is a positive mediator of uterine response. Finally, we show that exposure of ArKO females to dietary phytoestrogens results in their acquisition of uterine growth competence. Altogether our findings suggest that pubertal levels of endogenous and exogenous estrogens impact biological function of uterine cells later in life via ERα-dependent mechanisms. We compared uterine RNA from ovariectomized adult aromatase knockout mice (ARKO) mice that were untreated to WT mice and to ARKO that were administered estradiol benzoate (EB) to induce uterine epithelial cell growth competence
Project description:Estrogen receptor α (ERα) modulates gene expression through interactions with enhancer regions of chromatin that are frequently distal from the promoters of estrogen regulated genes. Active chromatin enriched “super-enhancer” (SE) regions, mainly described in in vitro culture systems, often control production of key cell type determining transcription factors. Here, we define ERα binding super-enhancers in vivo within hormone responsive uterine tissue. SE are already formed prior to estrogen exposure at the onset of puberty. The SE encode critical developmental factors including Rara and Hoxd. Using chromosome conformation capture with high throughput sequencing (Hi-C) we demonstrate that most ERα-binding SE are located at a chromatin loop end and most uterine genes in loop ends associated with ERα-binding SEs are estrogen regulated. Although SE are formed prior to puberty, SE-associated genes acquire optimal ERα dependent expression after reproductive maturity, indicating estrogen impacts enhancer function subsequent to assembly. ERα-binding SE-associated genes impact key uterine functions mediated by estrogen, including TGFβ and LIF signaling pathways. This is the first identification of ERα-binding SE interactions underlying hormonal regulation of genes in uterine tissue and optimal development of estrogen response
Project description:Our study revealed that hypoxia inducible factor 2 alpha, Hif2 alpha, is a downstream target of estrogen signaling in mouse uterine stroma at the time of implantation. Further, conditional deletion of Hif2 alpha in mouse uterus leads to infertility due to impaired epithelial remodeling at the time of implantation. To identify the downstream targets of Hif2 alpha in the uterus, we performed gene expression profiling of uterine stromal cells isolated from Hif2 alpha-intact and -null mice on day 5 of pregnancy, overlapping the window of implantation. The microarray results revealed altered expression of mRNAs corresponding to factors involved in protein trafficking in uterine stroma of Hif2 alpha-ablated mice. These factors mediate crosstalk between uterine storma and epithelial cells to promote epithelial remodeling and implantation. Thus, Hif2 alpha regulates embryo implantation by controlled trafficking of secretory granules during early pregnancy.
Project description:Estrogen receptors play critical roles in both the normal physiological, and disease states of numerous tissues, including breast and uterus. Estrogen receptor alpha (ER) can activate or repress the expression of target genes upon estrogen stimulation. In order to better understand the transcriptional network of ER in breast and uterus, we generated genome wide maps ofM-BM- ER binding sites (ERBS) and gene expression profiles in breast cancer cells (MCF7 and T47D) and uterine cancer cells (ECC1 and Ishikawa) through ChIP-Seq and microarray techniques. Surprisingly, we identified large scale differences in the numbers of ERBS between these cell lines when treated with E2 (17-M-NM-2 estradiol). Besides identification of common and unique ERBS between breast and uterine cancer cell types., our data also suggest that both cell types could recruit a large set of common co-operating transcription factors (Co-TFs) and a few unique Co-TFs as well. Besides the genes that are commonly regulatedM-BM- between the different cell lines, there are a number of genes that are differentially regulated in different cell types. Gene pathway analyses of E2 target genes suggest that ER regulates many biological pathways and processes in both tissue-type dependent and independent manners. Our results showed that cell lines derived from same tissue display a greater similarity for both profiles of ERBS and gene expression, and that the differential profiles of ER and preferential recruitment of some Co-TFs are the main determinants for the differential regulation of E2 signaling in breast and uterine cancer cells. In order to explore common and distinctive features of ERM-NM-1 (estrogen receptor alpha) binding profiles between breast and uterus, we generated eight ChIP-Seq libraries for the four cell lines (MCF7, T47D, ECC1 and Ishikawa) under two different treatments (E2, ethanol). In addition, we generated four control libraries for the four cell lines. For all treatment libraries, we generated about 7-12 million unique tags each. ER antibody catalog number is (Santa Cruz,sc-543).
Project description:The estrogen receptor-α (ERα) is a transcription factor which plays a critical role in controlling cell proliferation and tumorigenesis by recruiting various cofactors to estrogen response elements (EREs) to induce or repress gene transcription. A deeper understanding of these transcriptional mechanisms may uncover novel therapeutic targets for ERα-dependent cancers. Here we show for the first time that BRD4 regulates ERα−induced gene expression by affecting elongation-associated phosphorylation of RNA Polymerase II (RNAPII P-Ser2) and histone H2B monoubiquitination (H2Bub1). Consistently, BRD4 activity is required for estrogen-induced proliferation of ER+ breast and endometrial cancer cells and uterine growth in mice. Genome-wide occupancy studies revealed an enrichment of BRD4 on transcriptional start sites as well as EREs enriched for H3K27ac and demonstrate a requirement for BRD4 for H2B monoubiquitination in the transcribed region of estrogen-responsive genes. Importantly, we further demonstrate that BRD4 occupancy correlates with active mRNA transcription and is required for the production of ERα-dependent enhancer RNAs (eRNAs). These results uncover BRD4 as a central regulator of ERα function and potential therapeutic target. ChIP-sequencing of BRD4, ERα and H2Bub1 in MCF7 cells treated with +/- estrogen treatment and or +/- JQ1 treatment in triplicates.
Project description:Estrogens are steroid hormones that play critical roles in the initiation, development, and metastasis of breast and uterine cancers. The estrogen (E2) response in breast cancer cells is predominantly mediated by the estrogen receptor-alpha (ER alpha), a ligand-activated transcription factor. ER alpha regulates transcription of target genes through direct binding to its cognate recognition sites, known as estrogen response elements (EREs), or by modulating the activity of other DNA-bound transcription factors at alternative DNA sequences. The proto-oncogene c-myc is upregulated by ER¦Á in response to E2 and encodes a transcription factor, c-MYC, which regulates a cascade of gene targets whose products mediate cellular transformation. This study aims at mapping the binding sites of these two transcription factors (ER alpha and c-MYC) in one ER alpha positive breast cancer cell line (MCF7 cell line). Keywords: ChIP-Chip Analysis