HOTAIRM1 suppresses Estrogen Receptor activity in breast cancer by restricting chromatin accessibility of pioneer factor FOXA1
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PROVIDER: PRJNA560493 | ENA |
REPOSITORIES: ENA
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Project description:Although a majority of breast cancers (BrCa) are Estrogen receptor-alpha (ERa)-positive, existing endocrine therapies that target ERa can lead to hormone-resistant disease. The mechanisms of how normal breast epithelium is transformed into malignant remain poorly defined, and a deeper understanding is needed to design novel therapeutics. Several epigenetic regulators including long non-coding RNAs (lncRNAs) are aberrantly expressed in BrCa, resulting in abnormal gene expression patterns and tumor growth. Here, we show that HOTAIRM1, which we previously defined as a p53-regulated lncRNA in human stem cells, acts as a tumor suppressor to counteract ERa-activity in BrCa. Global expression analyses uncovered a significant correlation between reduced HOTAIRM1 expression and poor survival of ER+ BrCa patients. Promoter DNA methylation and histone mark enrichment revealed that HOTAIRM1 is epigenetically silenced in BrCa patients and cell lines. We found that HOTAIRM1 depletion promotes, whereas exogenous HOTAIRM1 reduces survival and proliferation of BrCa cells. Guilt by association analysis in BrCa patients, combined with HOTAIRM1-dependent transcriptome profiling in BrCa cells reveal that HOTAIRM1 expression negatively correlates with proteins involved in ERa-activity and estrogen response. An unbiased profiling of HOTAIRM1-interactome show that HOTAIRM1 interacts with pioneer factor FOXA1 in ER+ BrCa cells. Further, our global ER/FOXA1 chromatin enrichment profiling in response to estrogen demonstrate increased enrichment of ER and FOXA1 to estrogen response elements (EREs) that results in significantly higher expression of ERa-targets in absence of HOTAIRM1. Thus, HOTAIRM1 suppresses ERa-activity in BrCa by restricting chromatin accessibility of pioneer factor FOXA1. To our knowledge, our results are the first to define a non-proteomic component that disrupts the activity of a pioneer factor in order to achieve tumor suppression
2023-08-15 | GSE135894 | GEO
Project description:AR is tightly regulated by many transcriptional cofactors, including key pioneer factor such as FOXA1 and GATA2. While FOXA1 was recently shown to be able to redistribute AR across the genome, how GATA2 regulates AR cistrome has not been carefully investigated. Here, we report that, unlike FOXA1, GATA2 is unable to reprogram AR, but instead it enhances AR program by inducing AR expression and augmenting AR co-occupancy, thereby acting as a pure AR coactivator, rather than a pioneer factor. On the other hand, AR co-occupancy enhances both GATA2 and FOXA1 binding on the chromatin, forming a positive feedback loop. Importantly, we found that FOXA1 is also capable of reprogramming GATA2 by recruiting GATA2 from GATA motif to FKHD-containing regions, being analogous to its pioneering effect on AR signaling. By contrast, GATA2 simply acts as a co-activator of FOXA1 with a lack of pioneering ability. ChIP_Seq examination of AR, FoxA1 and GATA2 binding sites in LNCaP and DU145 cells
2016-01-11 | E-GEOD-69043 | biostudies-arrayexpress
Project description:AR is tightly regulated by many transcriptional cofactors, including key pioneer factor such as FOXA1 and GATA2. While FOXA1 was recently shown to be able to redistribute AR across the genome, how GATA2 regulates AR cistrome has not been carefully investigated. Here, we report that, unlike FOXA1, GATA2 is unable to reprogram AR, but instead it enhances AR program by inducing AR expression and augmenting AR co-occupancy, thereby acting as a pure AR coactivator, rather than a pioneer factor. On the other hand, AR co-occupancy enhances both GATA2 and FOXA1 binding on the chromatin, forming a positive feedback loop. Importantly, we found that FOXA1 is also capable of reprogramming GATA2 by recruiting GATA2 from GATA motif to FKHD-containing regions, being analogous to its pioneering effect on AR signaling. By contrast, GATA2 simply acts as a co-activator of FOXA1 with a lack of pioneering ability. genetic_modification_design
2016-01-11 | E-GEOD-69044 | biostudies-arrayexpress
Project description:Pioneer transcription factors (TFs) exhibit a special ability to bind to and open closed chromatin, facilitating engagement by other regulatory factors involved in gene activation or repression. Chemical probes are lacking for pioneer TFs, which has hindered their mechanistic investigation in cells. Here, we report electrophilic small molecules that stereoselectively and site-specifically bind the pioneer TF, FOXA1, at a cysteine (C258) within the forkhead DNA-binding domain. We show that these covalent ligands react with FOXA1 in a DNA-dependent manner and rapidly remodel its pioneer activity in prostate cancer cells reflected in redistribution of FOXA1 binding across the genome and directionally correlated changes in chromatin accessibility. Motif analysis supports a mechanism where the covalent ligands relax the canonical DNA binding preference of FOXA1 by strengthening interactions with suboptimal ancillary sequences in predicted proximity to C258. Our findings reveal a striking plasticity underpinning the pioneering function of FOXA1 that can be controlled by small molecules.
2024-09-05 | PXD050685 | Pride
Project description:FOXA1 is a pioneer factor that is important in hormone dependent cancer cells to stabilise nuclear receptors, such as estrogen receptor (ER) to chromatin. FOXA1 binds to enhancers regions that are enriched in H3K4mono- and dimethylation (H3K4me1, H3K4me2) histone marks and evidence suggests that these marks are requisite events for FOXA1 to associate with enhancers to initate subsequent gene expression events. However, exogenous expression of FOXA1 has been shown to induce H3K4me1 and H3K4me2 signal at enhancer elements and the order of events and the functional importance of these events is not clear. We performed a FOXA1 Rapid Immunoprecipitation Mass Spectrometry of Endogenous Proteins (RIME) screen in ERα-positive MCF-7 breast cancer cells in order to identify FOXA1 interacting partners and we found histone-lysine N-methyltransferase (MLL3) as the top FOXA1 interacting protein. MLL3 is typically thought to induce H3K4me3 at promoter regions, but recent findings suggest it may contribute to H3K4me1 deposition, in line with our observation that MLL3 associates with an enhancer specific protein. We performed MLL3 ChIP-seq in breast cancer cells and unexpectedly found that MLL3 binds mostly at non-promoter regions enhancers, in contrast to the prevailing hypothesis. MLL3 was shown to occupy regions marked by FOXA1 occupancy and as expected, H3K4me1 and H3K4me2. MLL3 binding was dependent on FOXA1, indicating that FOXA1 recruits MLL3 to chromatin. Motif analysis and subsequent genomic mapping revealed a role for Grainy head like protein-2 (GRHL2) which was shown to co-occupy regions of the chromatin with MLL3. Regions occupied by all three factors, namely FOXA1, MLL3 and GRHL2, were most enriched in H3K4me1. MLL3 silencing decreased H3K4me1 at enhancer elements, but had no appreciable impact on H3K4me3 at enhancer elements. We identify a complex relationship between FOXA1, MLL3 and H3K4me1 at enhancers in breast cancer and propose a mechanism whereby the pioneer factor FOXA1 can interact with a chromatin modifier MLL3, recruiting it to chromatin to facilitate the deposition of H3K4me1 histone marks, subsequently demarcating active enhancer elements.
2016-12-12 | PXD005253 | Pride
Project description:We and others have suggested that pioneer activity–a transcription factor’s (TF’s) ability to bind and open inaccessible loci–is not a qualitative trait limited to a select class of pioneer TFs. We hypothesize that most TFs display pioneering activity that depends on the TF concentration and the motif content at their target loci. Here we present a quantitative measure of pioneer activity that captures the relative difference in a TF’s ability to bind accessible versus inaccessible DNA. The metric is based on experiments that use CUT&Tag to measure binding of doxycycline (dox) inducible TFs. For each location across the genome we determine a “dox50,” the concentration of dox required for a TF to reach half-maximal occupancy. We propose that the ratio of a TF’s average dox50 between ATAC-seq labeled inaccessible and accessible binding sites, its Δdox50, is a measure of its pioneer activity. We measured Δdox50’s for the endodermal TFs FOXA1 and HNF4A and show that HNF4A has a smaller Δdox50 than FOXA1, suggesting that HNF4A has stronger pioneer activity than FOXA1. We further show that FOXA1 binding sites with more copies of its motif have a lower Δdox50, suggesting that strong motif content may compensate for weak pioneer activity. Our results suggest that Δdox50s, or other similar measures that assess the difference in TF affinity for inaccessible and accessible DNA, are reasonable measures of pioneer activity.
2022-05-27 | GSE204726 | GEO
Project description:We hormone deprived MCF-7 and ZR75-1 breast cancer cells for three days and treated them with vehicle (ethanol) or estrogen for 45 minutes. We then performed FOXA1 ChIP-seq and showed that the vast majority (>99%) of FOXA1 binding events are not affected by steroid conditions. A small number (<1%) of FOXA1 binding sites appear to be induced by estrogen, but these are not genuine de novo binding sites and represent ‘shadow’ binding sites that result from chromatin interactions at super-enhancer containing estrogen-regulated genomic regions. FOXA1 is therefore not regulated by estrogen and remains a bone fide therapeutic target that is entirely upstream of the ER complex.
2019-03-07 | GSE112969 | GEO
Project description:To investigate the target genes of HOTAIRM1 in glioma cells, we conducted a lncRNA + mRNA expression microarray analysis to identify novel HOTAIRM1 regulating genes. Three glioma cell lines U87MG, T98G and A172 stably knockdown HOTAIRM1 were used as the experiments models. We conservatively established a minimum of 2-fold difference between shHOTAIRM1 (knockdown HOTAIRM1) and shNT (control group), and identified 10 up-regulated and 22 down-regulated genes that met the threshold in all cell lines.
2021-12-26 | GSE192627 | GEO
Project description:Pioneer transcription factors, by interacting with nucleosomes, scan silent, compact chromatin to target regulatory sequences, enabling cooperative binding events that modulate local chromatin structure and gene activity. However, not all cognate motifs are targeted by pioneer factors and dynamic scanning parameters required to scan compact chromatin are unknown. A combined genomics and single-molecule tracking approach shows that to target DNase-resistant, low-histone turnover sites, pioneer factors FOXA1 and SOX2 display opposite dynamics of chromatin scanning: slow, with low nucleoplasmic diffusion and stable interactions, versus fast, with high nucleoplasmic diffusion and transient interactions, respectively. Despite such differences, the ability of FOXA1 and SOX2 to scan low-mobility chromatin, mediated by protein domains outside of the respective DNA binding domains, leads to targeting silent chromatin. By contrast, non-pioneer HNF4A predominantly targets DNase-sensitive, nucleosome-depleted regions. We conclude that the targeting of compact chromatin sites by pioneer factors can be performed through diverse dynamic processes. Chromatin immunoprecipitation DNA-sequencing (ChIP-seq) for HNF4A, FOXA1, FOXA1-DBD, FOXA1-NHAA, FOXA1-RRAA, as well as H2B-HALO after ectopic expression in human BJ fibroblast cells.
2023-06-07 | GSE220567 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE25314: FoxA1 is a critical determinant of Estrogen Receptor function and endocrine response (part I) GSE25315: FoxA1 is a critical determinant of Estrogen Receptor function and endocrine response (part II) Refer to individual Series
2010-11-17 | E-GEOD-25316 | biostudies-arrayexpress