Project description:Background: The ZNF217 gene, encoding a C2H2 zinc finger protein, is located at 20q13 and found amplified and overexpressed in greater than 20% of breast tumors. Current studies indicate ZNF217 drives tumorigenesis, yet the regulatory mechanisms of ZNF217 are largely unknown. Because ZNF217 associates with chromatin modifying enzymes, we postulate that ZNF217 functions to regulate specific gene signaling networks. Here, we present a large-scale functional genomic analysis of ZNF217, which provides insights into the regulatory role of ZNF217 in MCF7 breast cancer cells. Results: ChIP-seq analysis reveals that the majority of ZNF217 binding sites are located at distal regulatory regions associated with the chromatin marks H3K27ac and H3K4me1. Analysis of ChIPseq transcription factor binding sites shows clustering of ZNF217 with FOXA1, GATA3 and ERalpha binding sites, supported by the enrichment of corresponding motifs for the ERalpha-associated cisregulatory sequences. ERalpha expression highly correlates with ZNF217 in lysates from breast tumors (n=15), and ERalpha co-precipitates ZNF217 and its binding partner CtBP2 from nuclear extracts. Transcriptome profiling following ZNF217 depletion identifies differentially expressed genes co-bound by ZNF217 and ERalpha; gene ontology suggests a role for ZNF217-ERalpha in expression programs associated with ER+ breast cancer studies found in the Molecular Signature Database. Data-mining of expression data from breast cancer patients correlates ZNF217 with reduced overall survival in multiple subtypes. Conclusions: Our genome-wide ZNF217 data suggests a functional role for ZNF217 at ERalpha target genes. Future studies will investigate whether ZNF217 expression contributes to aberrant ERalpha regulatory events in ER+ breast cancer and hormone resistance
Project description:Background: The ZNF217 gene, encoding a C2H2 zinc finger protein, is located at 20q13 and found amplified and overexpressed in greater than 20% of breast tumors. Current studies indicate ZNF217 drives tumorigenesis, yet the regulatory mechanisms of ZNF217 are largely unknown. Because ZNF217 associates with chromatin modifying enzymes, we postulate that ZNF217 functions to regulate specific gene signaling networks. Here, we present a large-scale functional genomic analysis of ZNF217, which provides insights into the regulatory role of ZNF217 in MCF7 breast cancer cells. Results: ChIP-seq analysis reveals that the majority of ZNF217 binding sites are located at distal regulatory regions associated with the chromatin marks H3K27ac and H3K4me1. Analysis of ChIPseq transcription factor binding sites shows clustering of ZNF217 with FOXA1, GATA3 and ERalpha binding sites, supported by the enrichment of corresponding motifs for the ERalpha-associated cisregulatory sequences. ERalpha expression highly correlates with ZNF217 in lysates from breast tumors (n=15), and ERalpha co-precipitates ZNF217 and its binding partner CtBP2 from nuclear extracts. Transcriptome profiling following ZNF217 depletion identifies differentially expressed genes co-bound by ZNF217 and ERalpha; gene ontology suggests a role for ZNF217-ERalpha in expression programs associated with ER+ breast cancer studies found in the Molecular Signature Database. Data-mining of expression data from breast cancer patients correlates ZNF217 with reduced overall survival in multiple subtypes. Conclusions: Our genome-wide ZNF217 data suggests a functional role for ZNF217 at ERalpha target genes. Future studies will investigate whether ZNF217 expression contributes to aberrant ERalpha regulatory events in ER+ breast cancer and hormone resistance Differential RNA-seq profiling from triplicate biological replicates of MCF7 cells treated with scrambled siRNA or siZNF217.
Project description:Despite the role of the estrogen receptor alpha (ERalpha) pathway as a key growth driver for breast cells, the phenotypic consequence of exogenous introduction of ERalpha into ERalpha-negative cells paradoxically has been growth inhibition. We map the binding profiles of ERalpha and its interacting transcription factors (TFs), FOXA1 and GATA3 in MCF-7 breast carcinoma cells. We observe that these three TFs form a functional enhanceosome and cooperatively modulate the transcriptional networks previously ascribed to ERalpha alone. We demonstrate that these enhanceosome occupied sites are associated with optimal enhancer characteristics with highest p300 coactivator recruitment, RNA Pol II occupancy, and chromatin opening. The enhancesome binding sites appear to regulate the genes driving core ERalpha function. Most importantly, we show that the transfection of all three TFs was necessary to reprogramme the ERalpha-negative MDA-MB-231 and BT-459 cells to restore the estrogen responsive growth and to transcriptionally resemble the estrogen treated ERalpha-positive MCF-7 cells. Cumulatively, these results suggest that all the enhanceosome components comprising ERalpha, FOXA1 and GATA3 are necessary for the full repertoire of cancer associated effects of the ERalpha. Illumina HumanRef-8 v3 Expression BeadChip was used to measure the gene expression levels from ERalpha negative breast cancer cell MDA-MB-231 with different transfections: with vector control, with ERalpha only, or with ERalpha+FOXA1+GATA3 combined.
Project description:Estrogen receptor alpha (ERalpha signaling pathway is essential for ERalpha positive breast cancer progression and endocrine therapy resistance. BPTF associated protein of 18kDa (BAP18) has been recognized as a crucial H3K4me3 reader. However, the whole genomic occupation of BAP18 and its biological function in breast cancer are still elusive. Here, we found that higher expression of BAP18 in ERalpha positive breast cancer is positively correlated with poor prognosis. ChIP-seq analysis further demonstrated that the half estrogen response elements (EREs) and the CCCTC binding factor (CTCF) binding sites are the significant enrichment sites found in estrogen-induced BAP18 binding sites. In addition, we provide the evidence to demonstrate that BAP18 as a novel co-activator of ERalpha is required for the recruitment of COMPASS-like core subunits to cis-regulatory element of ERalpha target genes in breast cancer cells. BAP18 is recruited to the promoter regions of estrogen-induced genes, accompanied with the enrichment of the lysine 4-trimethylated histone H3 tail (H3K4me3) in the presence of E2. Furthermore, BAP18 promotes cell growth and confers to ERalpha antagonist tamoxifen resistancein ERalpha positive breast cancer. Our data suggest that BAP18 facilitates the association between ERalpha and COMPASS-like core subunits, which might be an essential epigenetic therapeutic target for breast cancer.
Project description:To obtain an overview of the cellular functions regulated by ZNF217 signaling in breast-cancer cell lines, we performed global gene-expression profiling on MDA-MB-231-pcDNA6 and MDA-MB-231-ZNF217 cells
Project description:Despite the role of the estrogen receptor alpha (ERalpha) pathway as a key growth driver for breast cells, the phenotypic consequence of exogenous introduction of ERalpha into ERalpha-negative cells paradoxically has been growth inhibition. We map the binding profiles of ERalpha and its interacting transcription factors (TFs), FOXA1 and GATA3 in MCF-7 breast carcinoma cells. We observe that these three TFs form a functional enhanceosome and cooperatively modulate the transcriptional networks previously ascribed to ERalpha alone. We demonstrate that these enhanceosome occupied sites are associated with optimal enhancer characteristics with highest p300 coactivator recruitment, RNA Pol II occupancy, and chromatin opening. The enhancesome binding sites appear to regulate the genes driving core ERalpha function. Most importantly, we show that the transfection of all three TFs was necessary to reprogramme the ERalpha-negative MDA-MB-231 and BT-459 cells to restore the estrogen responsive growth and to transcriptionally resemble the estrogen treated ERalpha-positive MCF-7 cells. Cumulatively, these results suggest that all the enhanceosome components comprising ERalpha, FOXA1 and GATA3 are necessary for the full repertoire of cancer associated effects of the ERalpha.
Project description:Despite the role of the estrogen receptor alpha (ERalpha) pathway as a key growth driver for breast cells, the phenotypic consequence of exogenous introduction of ERalpha into ERalpha-negative cells paradoxically has been growth inhibition. We map the binding profiles of ERalpha and its interacting transcription factors (TFs), FOXA1 and GATA3, in MCF-7 breast carcinoma cells. We observe that these three TFs form a functional enhanceosome and cooperatively modulate the transcriptional networks previously ascribed to ERalpha alone. We demonstrate that these enhanceosome-occupied sites are associated with optimal enhancer characteristics with highest p300 coactivator recruitment, RNA Pol II occupancy, and chromatin opening. The enhancesome binding sites appear to regulate the genes driving core ERalpha function. Most importantly, we show that transfection of all three TFs was necessary to reprogram the ERalpha-negative MDA-MB-231 and BT-459 cells to restore the estrogen responsive growth and to transcriptionally resemble the estrogen-treated ERalpha-positive MCF-7 cells. Cumulatively, these results suggest that all of the enhanceosome components comprising ERalpha, FOXA1 and GATA3 are necessary for the full repertoire of the cancer-associated effects of the ERalpha.
Project description:Estrogen receptor alpha (ERalpha) is a ligand-dependent transcription factor that plays an important role in breast cancer. Estrogen-dependent gene regulation by ERalpha can be mediated by interaction with other DNA-binding proteins, such as activator protein-1 (AP-1). The nature of such interactions in mediating the estrogen response in breast cancer cells remains unclear. Here we show that knockdown of c-Fos, a component of the transcription factor AP-1, attenuates the expression of 37% of all estrogen-regulated genes, suggesting that AP-1 is a fundamental factor for ERalpha-mediated transcription. Additionally, knockdown of c-Fos affected the expression of a number of genes that were not regulated by estrogen. Pathway analysis reveals that silencing of c-Fos downregulates an E2F1-dependent pro-proliferative gene network. Thus, modulation of the E2F1 pathway by c-Fos represents a novel mechanism by which c-Fos enhances breast cancer cell proliferation. Furthermore, we show that c-Fos and ERalpha can cooperate in regulating E2F1 gene expression by binding to regulatory elements in the E2F1 promoter. To start to dissect the molecular details of the cross-talk between AP-1 and estrogen signaling, we identify a novel ERalpha/AP-1 target, PKIB (cAMP-dependent protein kinase inhibitor-beta), which is overexpressed in ERalpha-positive breast cancer tissues. Knockdown of PKIB by siRNA results in drastic growth suppression of breast cancer cells. Collectively, our findings support AP-1 as a critical factor that governs estrogen-dependent gene expression and breast cancer proliferation programs. MCF-7 cells were transfected with a control siRNA or with the pool of siRNAs targeting c-Fos for 72 h and were then treated with vehicle or E2 for 24 h, and global gene expression profiles were assessed. Three or four biological replicates were used for each group.
Project description:The goal of this study is to identify ERalpha-target genes affected by overexpression of the histone arginine methyltransferase CARM1 in breast cancer cells. The roles of CARM1 in ERalpha+ breast cancer was not well characterized. Therefore, we created a Dox inducible CARM1 overexpressing MCF7 cell line where CARM1 is overexpressed by 2 fold to determine the created a Dox-inducible CARM1 overexpressing MCF7 cells for evaluation of the global effects of CARM1 on Eralpha-target gene expression.