Project description:Retinoic acid receptor-alpha (RAR alpha) is a known estrogen target gene in breast cancer cells. The consequence of RAR alpha induction by estrogen was previously unknown. We now show that RAR alpha is required for efficient estrogen receptor-alpha (ER)-mediated transcription and cell proliferation. RAR alpha can interact with ER-binding sites, but this occurs in an ER-dependent manner, providing a novel role for RAR alpha that is independent of its classic role. We show, on a genome-wide scale, that RAR alpha and ER can co-occupy regulatory regions together within the chromatin. This transcriptionally active co-occupancy and dependency occurs when exposed to the predominant breast cancer hormone, estrogen--an interaction that is promoted by the estrogen-ER induction of RAR alpha. These findings implicate RAR alpha as an essential component of the ER complex, potentially by maintaining ER-cofactor interactions, and suggest that different nuclear receptors can cooperate for effective transcriptional activity in breast cancer cells. RAR alpha silenced breast cancer MCF-7 cell lines or control siRNA in the presence of estrogen or a vehicle. MCF-7 cells were hormone-depleted for 3 d and treated with 100 nM estrogen for 12 h. There were three biological replicates for each of the four different groups.
Project description:The Estrogen Receptor alpha (ERa) is the key transcriptional regulator in luminal breast cancer and the main target for adjuvant treatment. Luminal gene signatures are dictated by the transcriptional capacities of ERa, which are a direct consequence of the receptors binding preference at specific sites on the chromatin. The identification of ERa binding signatures on a genome-wide level has greatly enhanced our understanding of Estrogen Receptor biology in cell lines, but the technique has its limitations with respect its applicability in limit amounts of tumor tissue. Here, we present a refinement of the ChIP-seq procedures to enable transcription factor mapping on limited amounts of tissue culture cells and illustrate the applicability of this refined technology by mapping the ERa genome-wide chromatin binding landscape in core needle biopsy material from primary breast tumors.
Project description:The forkhead transcription factor FOXM1 is a key regulator of the cell cycle and is overexpressed in cancer. Increased levels of FOXM1 are associated with both poor prognosis and oestrogen receptor (ERalpha) status in primary breast cancer. In this study, we map FOXM1 binding genome wide in both ERalpha-positive (MCF-7) and -negative (MDA-MB-231) breast cancer cells. We identify a common set of FOXM1 binding events at cell cycle-regulating genes, but in addition, in MCF-7 cells we find a high level of concordance with ERalpha-binding regions. FOXM1 binding at these co-binding sites is dependent on ERalpha binding, as depletion of ER protein levels reduced FOXM1 binding. FOXM1 interacts directly with both ERalpha co-activator CARM1 and is required for H3 arginine methylation at the ERalpha complex. Inhibition of FOXM1 activity with the ligand thiostrepton resulted in decreased FOXM1 binding at cca. 1400 sites genome wide and reduced expression of genes correlated with poor prognosis in ERalpha-positive tumour samples. These data demonstrate a novel role for the forkhead protein FOXM1 as an ERalpha cofactor and provide insight into the role of FOXM1 in ERalpha-positive breast cancer. MCF-7 cells were treated with either thiostrepton or DMSO for 6 hr. Each treatment was carried out in replicates of 6.
Project description:The forkhead transcription factor FOXM1 is a key regulator of the cell cycle and is overexpressed in cancer. Increased levels of FOXM1 are associated with both poor prognosis and oestrogen receptor (ERalpha) status in primary breast cancer. In this study, we map FOXM1 binding genome wide in both ERalpha-positive (MCF-7) and -negative (MDA-MB-231) breast cancer cells. We identify a common set of FOXM1 binding events at cell cycle-regulating genes, but in addition, in MCF-7 cells we find a high level of concordance with ERalpha-binding regions. FOXM1 binding at these co-binding sites is dependent on ERalpha binding, as depletion of ER protein levels reduced FOXM1 binding. FOXM1 interacts directly with both ERalpha co-activator CARM1 and is required for H3 arginine methylation at the ERalpha complex. Inhibition of FOXM1 activity with the ligand thiostrepton resulted in decreased FOXM1 binding at cca. 1400 sites genome wide and reduced expression of genes correlated with poor prognosis in ERalpha-positive tumour samples. These data demonstrate a novel role for the forkhead protein FOXM1 as an ERalpha cofactor and provide insight into the role of FOXM1 in ERalpha-positive breast cancer. The FOXM1-binding sites were mapped by ChIP-Seq in MCF-7 and MDA-MB-231 cells. Cells were treated either with thiostrepton, a FOXM1 inhibitor, or with DMSO (as control). Four replicates were performed in MCF7 cells and two replicates in MDA-MB-231 cells.
Project description:Retinoic acid receptor-alpha (RAR alpha) is a known estrogen target gene in breast cancer cells. The consequence of RAR alpha induction by estrogen was previously unknown. We now show that RAR alpha is required for efficient estrogen receptor-alpha (ER)-mediated transcription and cell proliferation. RAR alpha can interact with ER-binding sites, but this occurs in an ER-dependent manner, providing a novel role for RAR alpha that is independent of its classic role. We show, on a genome-wide scale, that RAR alpha and ER can co-occupy regulatory regions together within the chromatin. This transcriptionally active co-occupancy and dependency occurs when exposed to the predominant breast cancer hormone, estrogen--an interaction that is promoted by the estrogen-ER induction of RAR alpha. These findings implicate RAR alpha as an essential component of the ER complex, potentially by maintaining ER-cofactor interactions, and suggest that different nuclear receptors can cooperate for effective transcriptional activity in breast cancer cells.
Project description:The forkhead transcription factor FOXM1 is a key regulator of the cell cycle and is overexpressed in cancer. Increased levels of FOXM1 are associated with both poor prognosis and oestrogen receptor (ERalpha) status in primary breast cancer. In this study, we map FOXM1 binding genome wide in both ERalpha-positive (MCF-7) and -negative (MDA-MB-231) breast cancer cells. We identify a common set of FOXM1 binding events at cell cycle-regulating genes, but in addition, in MCF-7 cells we find a high level of concordance with ERalpha-binding regions. FOXM1 binding at these co-binding sites is dependent on ERalpha binding, as depletion of ER protein levels reduced FOXM1 binding. FOXM1 interacts directly with both ERalpha co-activator CARM1 and is required for H3 arginine methylation at the ERalpha complex. Inhibition of FOXM1 activity with the ligand thiostrepton resulted in decreased FOXM1 binding at cca. 1400 sites genome wide and reduced expression of genes correlated with poor prognosis in ERalpha-positive tumour samples. These data demonstrate a novel role for the forkhead protein FOXM1 as an ERalpha cofactor and provide insight into the role of FOXM1 in ERalpha-positive breast cancer.
Project description:The forkhead transcription factor FOXM1 is a key regulator of the cell cycle and is overexpressed in cancer. Increased levels of FOXM1 are associated with both poor prognosis and oestrogen receptor (ERalpha) status in primary breast cancer. In this study, we map FOXM1 binding genome wide in both ERalpha-positive (MCF-7) and -negative (MDA-MB-231) breast cancer cells. We identify a common set of FOXM1 binding events at cell cycle-regulating genes, but in addition, in MCF-7 cells we find a high level of concordance with ERalpha-binding regions. FOXM1 binding at these co-binding sites is dependent on ERalpha binding, as depletion of ER protein levels reduced FOXM1 binding. FOXM1 interacts directly with both ERalpha co-activator CARM1 and is required for H3 arginine methylation at the ERalpha complex. Inhibition of FOXM1 activity with the ligand thiostrepton resulted in decreased FOXM1 binding at cca. 1400 sites genome wide and reduced expression of genes correlated with poor prognosis in ERalpha-positive tumour samples. These data demonstrate a novel role for the forkhead protein FOXM1 as an ERalpha cofactor and provide insight into the role of FOXM1 in ERalpha-positive breast cancer.
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¦à 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 This series contains ChIP-on-Chip data sets for two transcription factors (ER alpha and c-MYC) and control samples (INPUT). All the experiments are done in triplicates. MCF7 Cells were E2-deprived for 3 days and then were treated with 10 nM E2 (45 minutes and 2 hours for mapping ER alpha and c-MYC binding sites, respectively) at 80% confluence.