Hypoxia and ERα Transcriptional Crosstalk Is Associated with Endocrine Resistance in Breast Cancer
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE111914 | GEO | 2022/10/06
REPOSITORIES: GEO
Similar Datasets
Project description:Estrogen Receptor alpha (ERα) is a ligand-inducible transcription factor that mediates estrogen signaling in hormone-responsive breast cancer (BC) and is the primary target of specific anticancer therapies that although effective can generate resistance phenomena that represents a crucial problem in clinical management of patients affected by this disease. DOT1 Like Histone Lysine Methyltransferase (DOT1L) and Menin 1 (MEN1) have been identified as functional component of the ERα mechanism of action. To investigate the involvement of DOT1L and MEN1 in mediating ERα actions in hormone-responsive and endocrine-resistant BC, interaction proteomics was applied to map the DOT1l and MEN1 nuclear interacting partners in MCF7 breast cancer cell nuclei in order to the identifiy new possible therapeutic targets for a more effective pharmacological treatment of endocrine therapy-resistant tumors.
2022-08-12 | PXD026864 | Pride
Project description:Estrogen Receptor alpha (ERα) is a ligand-inducible transcription factor that mediates estrogen signaling in hormone-responsive breast cancer (BC) and is the primary target of specific anticancer therapies. Although ERα blockade with these drugs is effective, the development of a resistance to treatment represents the key problem in clinical management of patients affected by this disease. Understanding the molecular mechanisms underlying ERα action in BC cells may help the identification of new therapeutic targets for more effective pharmacological treatment of endocrine therapy-resistant tumors. We recently discovered the epigenetic enzyme DOT1L (DOT1 Like Histone Lysine Methyltransferase) as a novel nuclear partner of ERα in BC cells. To investigate the involvement of DOT1L in mediating ERα actions in hormone-responsive and endocrine-resistant BC, physical and functional interaction between these two molecules on chromatin was mapped by Chromatin Immunoprecipitation coupled to Mass Spectrometry (ChIP-MS).
2019-02-09 | PXD010314 | Pride
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:This a model from the article:
Hypoxia-dependent sequestration of an oxygen sensor by a widespread structural motif can shape the hypoxic response - a predictive kinetic model
Bernhard Schmierer, Béla Novák1 and Christopher J Schofield
BMC Systems Biology2010, 4:139
20955552,
Abstract:
Background
The activity of the heterodimeric transcription factor hypoxia inducible factor (HIF) is regulated by the post-translational, oxygen-dependent hydroxylation of its α-subunit by members of the prolyl hydroxylase domain (PHD or EGLN)-family and by factor inhibiting HIF (FIH). PHD-dependent hydroxylation targets HIFα for rapid proteasomal degradation; FIH-catalysed asparaginyl-hydroxylation of the C-terminal transactivation domain (CAD) of HIFα suppresses the CAD-dependent subset of the extensive transcriptional responses induced by HIF. FIH can also hydroxylate ankyrin-repeat domain (ARD) proteins, a large group of proteins which are functionally unrelated but share common structural features. Competition by ARD proteins for FIH is hypothesised to affect FIH activity towards HIFα; however the extent of this competition and its effect on the HIF-dependent hypoxic response are unknown.
Results
To analyse if and in which way the FIH/ARD protein interaction affects HIF-activity, we created a rate equation model. Our model predicts that an oxygen-regulated sequestration of FIH by ARD proteins significantly shapes the input/output characteristics of the HIF system. The FIH/ARD protein interaction is predicted to create an oxygen threshold for HIFα CAD-hydroxylation and to significantly sharpen the signal/response curves, which not only focuses HIFα CAD-hydroxylation into a defined range of oxygen tensions, but also makes the response ultrasensitive to varying oxygen tensions. Our model further suggests that the hydroxylation status of the ARD protein pool can encode the strength and the duration of a hypoxic episode, which may allow cells to memorise these features for a certain time period after reoxygenation.
Conclusions
The FIH/ARD protein interaction has the potential to contribute to oxygen-range finding, can sensitise the response to changes in oxygen levels, and can provide a memory of the strength and the duration of a hypoxic episode. These emergent properties are predicted to significantly shape the characteristics of HIF activity in animal cells. We argue that the FIH/ARD interaction should be taken into account in studies of the effect of pharmacological inhibition of the HIF-hydroxylases and propose that the interaction of a signalling sensor with a large group of proteins might be a general mechanism for the regulation of signalling pathways.
There are there models described in the paper. 1) Skeleton Model 1 (SKM1) - HIFα CAD-hydroxylation in the absence of the FIH/AR-interaction. 2) Skeleton Model 2 (SKM2) - FIG sequestration by ARD proteins and oxygen-dependent FIH-release. 3) Full Model (Fusion of SKM1 and SKM2) - the effects of the FIH/ARD proteins interaction on HIFα CAD-hydroxylation.
This model corresponds to the "Full Model" described in the paper. The model reproduces figure 5 of the publication.
This model originates from BioModels Database: A Database of Annotated Published Models (http://www.ebi.ac.uk/biomodels/). It is copyright (c) 2005-2011 The BioModels.net Team.
For more information see the terms of use.
To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.
2024-09-02 | BIOMD0000000300 | BioModels
Project description:Estrogen receptor (ERα) is central in driving the development of hormone-dependent breast cancers. A major challenge in treating these cancers is to understand and struggle endocrine resistance. We have previously shown that the Megakaryoblastic Leukemia 1 (MKL1) protein, a master regulator of actin dynamic and cellular motile functions, directs down-regulation of ERα and hormonal escape of estrogen-responsive breast cancer cell lines. In the present study, we decipher the underlining mechanisms by tracking functional changes in ERα activity. We demonstrate through gene expression microarray analysis that the constitutive activation of MKL1 in ERα-positive MCF7 breast cancer cells induces a transition from a luminal to a basal-like phenotype and suppresses almost all regulations of gene expression by estrogen. Chromatin immunoprecipitation of DNA coupled to high-throughput sequencing (ChIP-Seq) shows a profound reprogramming in ERα cistrome associated with a massive loss of ERα binding sites (ERBSs) generally associated with lower ERα-binding activity. Novel ERBSs appear to be associated with EGF and RAS signaling pathways. ERα dynamic was further impacted by a displacement of its monomer/dimer equilibrium towards its monomer state, associated with a redistribution of the normally nuclear ERα protein to the entire cell volume. We next show that the combination of these remodeled dynamics of ERα alters its interactions with genomic and non-genomic partners. In particular, the formation of ERα/kinase complexes was promoted by the constitutive activation of MKL1. Hence, MKL1-induced transition of ER-positive breast cancer cells from luminal to basal-like phenotype shifts ERα activities from genomic to non-genomic function.
2019-12-31 | GSE107476 | GEO
Project description:Estrogen receptor (ERα) is central in driving the development of hormone-dependent breast cancers. A major challenge in treating these cancers is to understand and struggle endocrine resistance. We have previously shown that the Megakaryoblastic Leukemia 1 (MKL1) protein, a master regulator of actin dynamic and cellular motile functions, directs down-regulation of ERα and hormonal escape of estrogen-responsive breast cancer cell lines. In the present study, we decipher the underlining mechanisms by tracking functional changes in ERα activity. We demonstrate through gene expression microarray analysis that the constitutive activation of MKL1 in ERα-positive MCF7 breast cancer cells induces a transition from a luminal to a basal-like phenotype and suppresses almost all regulations of gene expression by estrogen. Chromatin immunoprecipitation of DNA coupled to high-throughput sequencing (ChIP-Seq) shows a profound reprogramming in ERα cistrome associated with a massive loss of ERα binding sites (ERBSs) generally associated with lower ERα-binding activity. Novel ERBSs appear to be associated with EGF and RAS signaling pathways. ERα dynamic was further impacted by a displacement of its monomer/dimer equilibrium towards its monomer state, associated with a redistribution of the normally nuclear ERα protein to the entire cell volume. We next show that the combination of these remodeled dynamics of ERα alters its interactions with genomic and non-genomic partners. In particular, the formation of ERα/kinase complexes was promoted by the constitutive activation of MKL1. Hence, MKL1-induced transition of ER-positive breast cancer cells from luminal to basal-like phenotype shifts ERα activities from genomic to non-genomic function.
2019-09-11 | GSE107924 | GEO
Project description:Tumour hypoxia is a recognised driver of breast cancer pathology. The main cellular response to hypoxia is mediated by the hypoxia-inducible factors HIF1 and HIF2, and is controlled through the regulation of oxygen-labile HIFα subunits. HIF1α has a well-established role in breast cancer where it has also been shown to be regulated by growth factor signalling. However, the role of HIF2α has been less thoroughly researched. Here, the role of HIF2α was investigated in breast cancer cell lines and publicly available gene expression datasets to determine its relationship with HER2 receptor expression in breast cancer. Using an isogenic cell line model for HER2 overexpression, we establish a direct role for HER2 in driving HIF2α expression in breast cancer. The effect of HER2-mediated HIF2α expression on the cellular response to acute and chronic hypoxia was investigated in 2D and 3D cell line models, and through protein and gene expression analysis, HER2 was shown to drive an exacerbated hypoxic response in these cells. In growth assays, HER2-overexpressing cell lines were shown to be highly sensitive to HIF2-specific inhibition through HIF2α-targeted siRNA and treatment with the HIF2α-specific translation inhibitor C76. Additionally, survival analysis in a large, publicly available dataset demonstrated a relationship between HIF2α and poor disease-specific survival in HER2-overexpressing tumours. We demonstrate a novel role for HIF2α in driving an increased hypoxic response in breast cancer cells and suggest HIF2 signalling may be an important, targetable pathway in HER2-positive breast cancers.
2018-03-01 | GSE111246 | GEO
Project description:Resistance to endocrine therapy represents a major threat to patients with estrogen receptor α positive (ERα+) breast cancer. The development of resistance is mainly through activating E2F signaling. However, the mechanisms that govern E2F1 activity in these resistant cells remain poorly understood. Here, we identify Actin Gamma 1 Pseudogene 25 (AGPG) as a lncRNA whose expression is driven by epigenomic activation of enhancer in endocrine resistant breast cancer cells. High expression of AGPG is associated with poor survival of ERα+ breast cancer, especially in patients receiving endocrine therapy. Stable knockdown and overexpression of AGPG demonstrate that AGPG promotes endocrine resistance, cell cycle progression, cell proliferation in vitro and in vivo. AGPG functions by direct binding purine rich element binding protein α (PURα), a transcription factor repressing E2F1 signaling and sensitized ERα+ breast cancer cells to endocrine therapy. Via binding to the region responsible for PURα/E2F1 interaction in PURα protein, AGPG releases E2F1 from PURα, leading to activation of E2F1 signaling in ERα+ breast cancer cells. Clinically, E2F1 target genes are strongly correlated with AGPG and PURα expression. Thus, our study reveals AGPG as a promising biomarker and potential therapeutic target in breast cancer.
2023-07-12 | GSE218130 | GEO
Project description:MicroRNAs (miRNAs) regulate a wide range of cellular signaling pathways and biological processes in both physiological and pathological states such as cancer. We have previously identified miR-135b as a direct regulator of androgen receptor (AR) protein level in prostate cancer (PCa). We wanted to further explore the relationship of miR-135b to hormonal receptors, particularly estrogen receptor α (ERα). Here we show that miR-135b expression inversely correlates with ER protein in two independent breast cancer (BCa) patient cohorts (101 and 1302 samples) and with AR protein in 47 PCa patient samples. We identify ERα as a novel miR-135b target by demonstrating miR-135b binding to the 3’UTR of the ERα and decreased ERα protein and mRNA level in breast cancer cells upon miR-135b overexpression. miR-135b inhibits proliferation of hormone receptor positive cancer cell lines as shown by overexpression in ERα-positive BCa cells (MCF-7) and AR-positive PCa cells (LNCaP, 22Rv1) when grown in 2D. To identify other genes regulated by miR-135b we performed gene expression studies and found a potential link to the hypoxia-inducible factor-1α (HIF1α) pathway. We show that miR-135b influences the protein level of the inhibitor for hypoxia-inducible factor-1 (HIF1AN), which also demonstrated an inverse correlation with miR-135b in a cohort of breast tumor samples. Taken together, our study demonstrates that miR-135b regulates ERα, AR and HIF1AN protein levels and proliferation in ERα -positive breast and AR-positive-prostate cancer cells.
2015-04-21 | GSE57820 | GEO
Project description:a.Background Cancer resequencing studies have revealed epigenetic enzymes as common targets for recurrent mutations. The monomethyltransferase MLL3 is among the most recurrently mutated enzymes in ER+ breast cancer. The H3K4me1 marks created by MLL3 can define enhancers. In ER+ breast cancer, ERα genome binding sites are primarily distal enhancers. Thus, we hypothesize that mutation of MLL3 will alter the genomic binding and transcriptional regulatory activity of ERα. b.Methods We investigated the genomic consequences of knocking down MLL3 in an MLL3/PIK3CA WT ER+ breast cancer cell line. c. Results Loss of MLL3 led to large loss of H3K4me1 across the genome, and a shift in ERα binding sites, which was accompanied by a re-organization of the breast cancer transcriptome. Enrichment analyses of ERα binding sites in MLL3 KD identified endocrine therapy resistance terms, and we show that MLL3 KD cells are resistant to tamoxifen and fulvestrant. Many differentially expressed genes are controlled by new locations of H3K4me1 deposition and ERα binding, suggesting that loss of functional MLL3 leads to new transcriptional regulation of essential genes. Motif analysis of RNA-seq and ChIP-seq data highlighted SP1 as a critical transcription factor in the MLL3 KD cells. Loss of ERα binding is accompanied by a massive increase in SP1 binding at differentially expressed genes. d.Conclusions Our data show that loss of functional MLL3 leads to endocrine therapy resistance. This highlights the importance of genotyping patient tumor samples for MLL3 mutation upon initial resection, prior to deciding upon treatment plans.
2020-12-16 | GSE163264 | GEO