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Kim HB, Kraus WL. Intracellular Retention of Estradiol is Augmented by GRAM Domain Containing Protein ASTER-B in Breast Cancer Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.16.594581. [PMID: 38826375 PMCID: PMC11142117 DOI: 10.1101/2024.05.16.594581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Estrogens are naturally occurring steroid hormones that also act as the primary mitogens for estrogen receptor-positive (ER+) breast cancers. While elevated blood levels of estrogens have been associated with poor prognosis, the relationship between circulating hormone levels in the blood are related to intracellular hormone concentrations. Here, we observed that MCF-7 cells acutely treated with 17β-estradiol (E2) retain a substantial amount of the hormone even upon removal of the hormone from the culture medium. Moreover, global patterns of E2-dependent gene expression are sustained for hours after acute E2 treatment and hormone removal. While circulating E2 is sequestered by sex hormone binding globulin (SHBG), the mechanisms of intracellular E2 retention are poorly understood. We found that a mislocalized GRAM-domain containing protein ASTER-B in the nucleus, which is observed in a subset of patients, is associated with higher cellular E2 retention. Accumulation and retention of hormone are related to the steroidal properties of E2. Finally, we observed that nuclear ASTER-B-mediated E2 retention is required for sustained hormone-induced ERα chromatin occupancy at enhancers and gene expression, as well as subsequent cell growth responses. Our results add intracellular hormone retention as a mechanism controlling E2-dependent gene expression and downstream biological outcomes. S ignificance This study advances our understanding of how estradiol can be accumulated and retained intracellularly to drive a pro-proliferative gene expression program in ER+ breast cancer cells. Mechanistically, intracellular E2 retention is mediated in part by mislocalized, nuclear ASTER-B, which is aberrantly localized to the nuclei of cancer cells in some breast cancer patients.
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Wang S, Sun H, Chen G, Wu C, Sun B, Lin J, Lin D, Zeng D, Lin B, Huang G, Lu X, Lin H, Liang Y. RNA-binding proteins in breast cancer: Biological implications and therapeutic opportunities. Crit Rev Oncol Hematol 2024; 195:104271. [PMID: 38272151 DOI: 10.1016/j.critrevonc.2024.104271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 01/05/2024] [Accepted: 01/19/2024] [Indexed: 01/27/2024] Open
Abstract
RNA-binding proteins (RBPs) refer to a class of proteins that participate in alternative splicing, RNA stability, polyadenylation, localization and translation of RNAs, thus regulating gene expression in post-transcriptional manner. Dysregulation of RNA-RBP interaction contributes to various diseases, including cancer. In breast cancer, disorders in RBP expression and function influence the biological characteristics of tumor cells. Targeting RBPs has fostered the development of innovative therapies for breast cancer. However, the RBP-related mechanisms in breast cancer are not completely clear. In this review, we summarize the regulatory mechanisms of RBPs and their signaling crosstalk in breast cancer. Specifically, we emphasize the potential of certain RBPs as prognostic factors due to their effects on proliferation, invasion, apoptosis, and therapy resistance of breast cancer cells. Most importantly, we present a comprehensive overview of the latest RBP-related therapeutic strategies and novel therapeutic targets that have proven to be useful in the treatment of breast cancer.
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Affiliation(s)
- Shimeng Wang
- Department of Thyroid and Breast Surgery, Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College (SUMC), 57 Changping Road, Shantou 515041, China
| | - Hexing Sun
- Department of Thyroid and Breast Surgery, Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College (SUMC), 57 Changping Road, Shantou 515041, China
| | - Guanyuan Chen
- Department of Thyroid and Breast Surgery, Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College (SUMC), 57 Changping Road, Shantou 515041, China
| | - Chengyu Wu
- Department of Thyroid and Breast Surgery, Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College (SUMC), 57 Changping Road, Shantou 515041, China
| | - Bingmei Sun
- Department of Thyroid and Breast Surgery, Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College (SUMC), 57 Changping Road, Shantou 515041, China
| | - Jiajia Lin
- Department of Thyroid and Breast Surgery, Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College (SUMC), 57 Changping Road, Shantou 515041, China
| | - Danping Lin
- Department of Medical Oncology, Cancer Hospital of SUMC, Shantou 515000, China
| | - De Zeng
- Department of Medical Oncology, Cancer Hospital of SUMC, Shantou 515000, China
| | - Baohang Lin
- Department of Thyroid, Breast and Vascular Surgery, Longgang District Central Hospital of Shenzhen, Shenzhen 518116, China
| | - Guan Huang
- Department of Pathology, Longgang District Central Hospital of Shenzhen, Shenzhen 518116, China
| | - Xiaofeng Lu
- Department of Thyroid and Breast Surgery, Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College (SUMC), 57 Changping Road, Shantou 515041, China
| | - Haoyu Lin
- Department of Thyroid and Breast Surgery, Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College (SUMC), 57 Changping Road, Shantou 515041, China.
| | - Yuanke Liang
- Department of Thyroid and Breast Surgery, Clinical Research Center, The First Affiliated Hospital of Shantou University Medical College (SUMC), 57 Changping Road, Shantou 515041, China.
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Liu L, Zhao Y, Siepel A. DNA-sequence and epigenomic determinants of local rates of transcription elongation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.21.572932. [PMID: 38187771 PMCID: PMC10769381 DOI: 10.1101/2023.12.21.572932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Across all branches of life, transcription elongation is a crucial, regulated phase in gene expression. Many recent studies in eukaryotes have focused on the regulation of promoter-proximal pausing of RNA Polymerase II (Pol II), but rates of productive elongation also vary substantially throughout the gene body, both within and across genes. Here, we introduce a probabilistic model for systematically evaluating potential determinants of the local elongation rate based on nascent RNA sequencing (NRS) data. Our model is derived from a unified model for both the kinetics of Pol II movement along the DNA template and the generation of NRS read counts at steady state. It allows for a continuously variable elongation rate along the gene body, with the rate at each nucleotide defined by a generalized linear relationship with nearby genomic and epigenomic features. High-dimensional feature vectors are accommodated through a sparse-regression extension. We show with simulations that the model allows accurate detection of associated features and accurate prediction of local elongation rates. In an analysis of public PRO-seq and epigenomic data, we identify several features that are strongly associated with reductions in the local elongation rate, including DNA methylation, splice sites, RNA stem-loops, CTCF binding sites, and several histone marks, including H3K36me3 and H4K20me1. By contrast, low-complexity sequences and H3K79me2 marks are associated with increases in elongation rate. In an analysis of DNA k -mers, we find that cytosine nucleotides are strongly associated with reductions in local elongation rate, particularly when preceded by guanines and followed by adenines or thymines. Increases in elongation rate are associated with thymines and A+T-rich k -mers. These associations are generally shared across cell types, and by considering them our model is effective at predicting features of held-out PRO-seq data. Overall, our analysis is the first to permit genome-wide predictions of relative nucleotide-specific elongation rates based on complex sets of genomic and epigenomic covariates. We have made predictions available for the K562, CD14+, MCF-7, and HeLa-S3 cell types in a UCSC Genome Browser track.
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Affiliation(s)
- Lingjie Liu
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
- Graduate Program in Genetics, Stony Brook University, Stony Brook, NY
| | - Yixin Zhao
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
| | - Adam Siepel
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
- Graduate Program in Genetics, Stony Brook University, Stony Brook, NY
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Abstract
Enhancers are cis-regulatory elements that can stimulate gene expression from distance, and drive precise spatiotemporal gene expression profiles during development. Functional enhancers display specific features including an open chromatin conformation, Histone H3 lysine 27 acetylation, Histone H3 lysine 4 mono-methylation enrichment, and enhancer RNAs production. These features are modified upon developmental cues which impacts their activity. In this review, we describe the current state of knowledge about enhancer functions and the diverse chromatin signatures found on enhancers. We also discuss the dynamic changes of enhancer chromatin signatures, and their impact on lineage specific gene expression profiles, during development or cellular differentiation.
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Affiliation(s)
- Amandine Barral
- Institute for Regenerative Medicine, Epigenetics Institute, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA,CONTACT Amandine Barral Institute for Regenerative Medicine, Epigenetics Institute, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania. 3400 Civic Blvd, Philadelphia, Pennsylvania19104, USA
| | - Jérôme Déjardin
- Biology of repetitive sequences, Institute of Human Genetics CNRS-Université de Montpellier UMR 9002, Montpellier, France,Jérôme Déjardin Biology of repetitive sequences, Institute of Human Genetics CNRS-Université de Montpellier UMR 9002, 141 rue de la Cardonille, Montpellier34000, France
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Peterson JM, O'Leary CA, Coppenbarger EC, Tompkins VS, Moss WN. Discovery of RNA secondary structural motifs using sequence-ordered thermodynamic stability and comparative sequence analysis. MethodsX 2023; 11:102275. [PMID: 37448951 PMCID: PMC10336498 DOI: 10.1016/j.mex.2023.102275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 06/28/2023] [Indexed: 07/18/2023] Open
Abstract
Major advances in RNA secondary structural motif prediction have been achieved in the last few years; however, few methods harness the predictive power of multiple approaches to deliver in-depth characterizations of local RNA motifs and their potential functionality. Additionally, most available methods do not predict RNA pseudoknots. This work combines complementary bioinformatic systems into one robust discovery pipeline where: •RNA sequences are folded to search for thermodynamically favorable motifs utilizing ScanFold.•Motifs are expanded and refolded into alternate pseudoknot conformations by Knotty/Iterative HFold.•All conformations are evaluated for covariance via the cm-builder pipeline (Infernal and R-scape).
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Gao Z, Smith AL, Scott JF, Bevington S, Boyes J. Temporal analyses reveal a pivotal role for sense and antisense enhancer RNAs in coordinate immunoglobulin lambda locus activation. Nucleic Acids Res 2023; 51:10344-10363. [PMID: 37702072 PMCID: PMC10602925 DOI: 10.1093/nar/gkad741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 08/24/2023] [Accepted: 08/30/2023] [Indexed: 09/14/2023] Open
Abstract
Transcription enhancers are essential activators of V(D)J recombination that orchestrate non-coding transcription through complementary, unrearranged gene segments. How transcription is coordinately increased at spatially distinct promoters, however, remains poorly understood. Using the murine immunoglobulin lambda (Igλ) locus as model, we find that three enhancer-like elements in the 3' Igλ domain, Eλ3-1, HSCλ1 and HSE-1, show strikingly similar transcription factor binding dynamics and close spatial proximity, suggesting that they form an active enhancer hub. Temporal analyses show coordinate recruitment of complementary V and J gene segments to this hub, with comparable transcription factor binding dynamics to that at enhancers. We find further that E2A, p300, Mediator and Integrator bind to enhancers as early events, whereas YY1 recruitment and eRNA synthesis occur later, corresponding to transcription activation. Remarkably, the interplay between sense and antisense enhancer RNA is central to both active enhancer hub formation and coordinate Igλ transcription: Antisense Eλ3-1 eRNA represses Igλ activation whereas temporal analyses demonstrate that accumulating levels of sense eRNA boost YY1 recruitment to stabilise enhancer hub/promoter interactions and lead to coordinate transcription activation. These studies therefore demonstrate for the first time a critical role for threshold levels of sense versus antisense eRNA in locus activation.
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Affiliation(s)
- Zeqian Gao
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Alastair L Smith
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - James N F Scott
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Sarah L Bevington
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Joan Boyes
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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Chen Q, Zeng Y, Kang J, Hu M, Li N, Sun K, Zhao Y. Enhancer RNAs in transcriptional regulation: recent insights. Front Cell Dev Biol 2023; 11:1205540. [PMID: 37266452 PMCID: PMC10229774 DOI: 10.3389/fcell.2023.1205540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 05/09/2023] [Indexed: 06/03/2023] Open
Abstract
Enhancers are a class of cis-regulatory elements in the genome that instruct the spatiotemporal transcriptional program. Last decade has witnessed an exploration of non-coding transcripts pervasively transcribed from active enhancers in diverse contexts, referred to as enhancer RNAs (eRNAs). Emerging evidence unequivocally suggests eRNAs are an important layer in transcriptional regulation. In this mini-review, we summarize the well-established regulatory models for eRNA actions and highlight the recent insights into the structure and chemical modifications of eRNAs underlying their functions. We also explore the potential roles of eRNAs in transcriptional condensates.
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Affiliation(s)
- Qi Chen
- The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Yaxin Zeng
- Molecular Cancer Research Center, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Jinjin Kang
- Molecular Cancer Research Center, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Minghui Hu
- Molecular Cancer Research Center, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Nianle Li
- Molecular Cancer Research Center, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Kun Sun
- Institute of Cancer Research, Shenzhen Bay Laboratory, Shenzhen, China
| | - Yu Zhao
- Molecular Cancer Research Center, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
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Gibbons MD, Fang Y, Spicola AP, Linzer N, Jones SM, Johnson BR, Li L, Xie M, Bungert J. Enhancer-Mediated Formation of Nuclear Transcription Initiation Domains. Int J Mol Sci 2022; 23:ijms23169290. [PMID: 36012554 PMCID: PMC9409229 DOI: 10.3390/ijms23169290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/14/2022] [Accepted: 08/16/2022] [Indexed: 11/16/2022] Open
Abstract
Enhancers in higher eukaryotes and upstream activating sequences (UASs) in yeast have been shown to recruit components of the RNA polymerase II (Pol II) transcription machinery. At least a fraction of Pol II recruited to enhancers in higher eukaryotes initiates transcription and generates enhancer RNA (eRNA). In contrast, UASs in yeast do not recruit transcription factor TFIIH, which is required for transcription initiation. For both yeast and mammalian systems, it was shown that Pol II is transferred from enhancers/UASs to promoters. We propose that there are two modes of Pol II recruitment to enhancers in higher eukaryotes. Pol II complexes that generate eRNAs are recruited via TFIID, similar to mechanisms operating at promoters. This may involve the binding of TFIID to acetylated nucleosomes flanking the enhancer. The resulting eRNA, together with enhancer-bound transcription factors and co-regulators, contributes to the second mode of Pol II recruitment through the formation of a transcription initiation domain. Transient contacts with target genes, governed by proteins and RNA, lead to the transfer of Pol II from enhancers to TFIID-bound promoters.
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Abstract
Enhancers confer precise spatiotemporal patterns of gene expression in response to developmental and environmental stimuli. Over the last decade, the transcription of enhancer RNAs (eRNAs) – nascent RNAs transcribed from active enhancers – has emerged as a key factor regulating enhancer activity. eRNAs are relatively short-lived RNA species that are transcribed at very high rates but also quickly degraded. Nevertheless, eRNAs are deeply intertwined within enhancer regulatory networks and are implicated in a number of transcriptional control mechanisms. Enhancers show changes in function and sequence over evolutionary time, raising questions about the relationship between enhancer sequences and eRNA function. Moreover, the vast majority of single nucleotide polymorphisms associated with human complex diseases map to the non-coding genome, with causal disease variants enriched within enhancers. In this Primer, we survey the diverse roles played by eRNAs in enhancer-dependent gene expression, evaluating different models for eRNA function. We also explore questions surrounding the genetic conservation of enhancers and how this relates to eRNA function and dysfunction. Summary: This Primer evaluates the ideas that underpin developing models for eRNA function, exploring cases in which perturbed eRNA function contributes to disease.
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Affiliation(s)
- Laura J. Harrison
- Molecular and Cellular Biology, School of Biosciences, Sheffield Institute For Nucleic Acids, The University of Sheffield, Firth Court, Western Bank , Sheffield S10 2TN , UK
| | - Daniel Bose
- Molecular and Cellular Biology, School of Biosciences, Sheffield Institute For Nucleic Acids, The University of Sheffield, Firth Court, Western Bank , Sheffield S10 2TN , UK
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