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Nasif D, Laurito S, Real S, Branham MT. Exploring the epigenetic profile of ID4 in breast cancer: bioinformatic insights into methylation patterns and chromatin accessibility dynamics. Breast Cancer Res Treat 2024; 207:91-101. [PMID: 38702584 DOI: 10.1007/s10549-024-07343-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 04/10/2024] [Indexed: 05/06/2024]
Abstract
PURPOSE Inhibitor of differentiation 4 (ID4) is a dominant-negative regulator of basic helix-loop-helix (bHLH) transcription factors. The expression of ID4 is dysregulated in various breast cancer subtypes, indicating a potential role for ID4 in subtype-specific breast cancer development. This study aims to elucidate the epigenetic regulation of ID4 within breast cancer subtypes, with a particular focus on DNA methylation and chromatin accessibility. METHODS Bioinformatic analyses were conducted to assess DNA methylation and chromatin accessibility in ID4 regulatory regions across breast cancer subtypes. Gene Set Enrichment Analysis (GSEA) was conducted to identify related gene sets. Transcription factor binding within ID4 enhancer and promoter regions was explored. In vitro experiments involved ER+ breast cancer cell lines treated with estradiol (E2) and Tamoxifen. RESULTS Distinct epigenetic profiles of ID4 were observed, revealing increased methylation and reduced chromatin accessibility in luminal subtypes compared to the basal subtype. Gene Set Enrichment Analysis (GSEA) implicated estrogen-related pathways, suggesting a potential link between estrogen signaling and the regulation of ID4 expression. Transcription factor analysis identified ER and FOXA1 as regulators of ID4 enhancer regions. In vitro experiments confirmed the role of ER, demonstrating reduced ID4 expression and increased methylation with estradiol treatment. Conversely, Tamoxifen treatment increased ID4 expression, indicating the potential involvement of ER signaling through ERα in the epigenetic regulation of ID4 in breast cancer cells. CONCLUSION This study shows the intricate epigenetic regulation of ID4 in breast cancer, highlighting subtype-specific differences in DNA methylation and chromatin accessibility.
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Affiliation(s)
- Daniela Nasif
- Institute of Histology and Embryology, National Council of Scientific and Technological Research (CONICET), Parque General San Martin, 5500, Mendoza, Argentina
| | - Sergio Laurito
- Institute of Histology and Embryology, National Council of Scientific and Technological Research (CONICET), Parque General San Martin, 5500, Mendoza, Argentina
- Faculty of Exact and Natural Sciences, National University of Cuyo, Parque General San Martin, 5500, Mendoza, Argentina
| | - Sebastian Real
- Institute of Histology and Embryology, National Council of Scientific and Technological Research (CONICET), Parque General San Martin, 5500, Mendoza, Argentina
- Faculty of Medical Science, National University of Cuyo, Parque General San Martin, 5500, Mendoza, Argentina
| | - María Teresita Branham
- Institute of Histology and Embryology, National Council of Scientific and Technological Research (CONICET), Parque General San Martin, 5500, Mendoza, Argentina.
- Faculty of Medical Science, University of Mendoza, Boulogne Sur Mer 683, 5500, Mendoza, Argentina.
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Nair VD, Pincas H, Smith GR, Zaslavsky E, Ge Y, Amper MAS, Vasoya M, Chikina M, Sun Y, Raja AN, Mao W, Gay NR, Esser KA, Smith KS, Zhao B, Wiel L, Singh A, Lindholm ME, Amar D, Montgomery S, Snyder MP, Walsh MJ, Sealfon SC. Molecular adaptations in response to exercise training are associated with tissue-specific transcriptomic and epigenomic signatures. CELL GENOMICS 2024; 4:100421. [PMID: 38697122 PMCID: PMC11228891 DOI: 10.1016/j.xgen.2023.100421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 07/07/2023] [Accepted: 09/12/2023] [Indexed: 05/04/2024]
Abstract
Regular exercise has many physical and brain health benefits, yet the molecular mechanisms mediating exercise effects across tissues remain poorly understood. Here we analyzed 400 high-quality DNA methylation, ATAC-seq, and RNA-seq datasets from eight tissues from control and endurance exercise-trained (EET) rats. Integration of baseline datasets mapped the gene location dependence of epigenetic control features and identified differing regulatory landscapes in each tissue. The transcriptional responses to 8 weeks of EET showed little overlap across tissues and predominantly comprised tissue-type enriched genes. We identified sex differences in the transcriptomic and epigenomic changes induced by EET. However, the sex-biased gene responses were linked to shared signaling pathways. We found that many G protein-coupled receptor-encoding genes are regulated by EET, suggesting a role for these receptors in mediating the molecular adaptations to training across tissues. Our findings provide new insights into the mechanisms underlying EET-induced health benefits across organs.
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Affiliation(s)
- Venugopalan D Nair
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Hanna Pincas
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Gregory R Smith
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Elena Zaslavsky
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yongchao Ge
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Mary Anne S Amper
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Mital Vasoya
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Maria Chikina
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yifei Sun
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | | | - Weiguang Mao
- Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Nicole R Gay
- Department of Genetics, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Karyn A Esser
- Department of Physiology and Aging, University of Florida, Gainesville, FL 32610, USA
| | - Kevin S Smith
- Departments of Pathology and Genetics, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Bingqing Zhao
- Department of Genetics, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Laurens Wiel
- Department of Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Aditya Singh
- Department of Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Malene E Lindholm
- Department of Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - David Amar
- Department of Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Stephen Montgomery
- Departments of Pathology and Genetics, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Michael P Snyder
- Department of Genetics, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Martin J Walsh
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Stuart C Sealfon
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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Peng Y, Song W, Teif VB, Ovcharenko I, Landsman D, Panchenko AR. Detection of new pioneer transcription factors as cell-type-specific nucleosome binders. eLife 2024; 12:RP88936. [PMID: 38293962 PMCID: PMC10945518 DOI: 10.7554/elife.88936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024] Open
Abstract
Wrapping of DNA into nucleosomes restricts accessibility to DNA and may affect the recognition of binding motifs by transcription factors. A certain class of transcription factors, the pioneer transcription factors, can specifically recognize their DNA binding sites on nucleosomes, initiate local chromatin opening, and facilitate the binding of co-factors in a cell-type-specific manner. For the majority of human pioneer transcription factors, the locations of their binding sites, mechanisms of binding, and regulation remain unknown. We have developed a computational method to predict the cell-type-specific ability of transcription factors to bind nucleosomes by integrating ChIP-seq, MNase-seq, and DNase-seq data with details of nucleosome structure. We have demonstrated the ability of our approach in discriminating pioneer from canonical transcription factors and predicted new potential pioneer transcription factors in H1, K562, HepG2, and HeLa-S3 cell lines. Last, we systematically analyzed the interaction modes between various pioneer transcription factors and detected several clusters of distinctive binding sites on nucleosomal DNA.
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Affiliation(s)
- Yunhui Peng
- Institute of Biophysics and Department of Physics, Central China Normal UniversityWuhanChina
- National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Wei Song
- National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Vladimir B Teif
- School of Life Sciences, University of Essex, Wivenhoe ParkColchesterUnited Kingdom
| | - Ivan Ovcharenko
- National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - David Landsman
- National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Anna R Panchenko
- Department of Pathology and Molecular Medicine, Queen’s UniversityKingstonCanada
- Department of Biology and Molecular Sciences, Queen’s UniversityKingstonCanada
- School of Computing, Queen’s UniversityKingstonCanada
- Ontario Institute of Cancer ResearchTorontoCanada
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Wei H, Zhong Z, Li Z, Zhang Y, Stukenbrock EH, Tang B, Yang N, Baroncelli R, Peng L, Liu Z, He X, Yang Y, Yuan Z. Loss of the accessory chromosome converts a pathogenic tree-root fungus into a mutualistic endophyte. PLANT COMMUNICATIONS 2024; 5:100672. [PMID: 37563834 PMCID: PMC10811371 DOI: 10.1016/j.xplc.2023.100672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 06/01/2023] [Accepted: 08/04/2023] [Indexed: 08/12/2023]
Abstract
Some fungal accessory chromosomes (ACs) may contribute to virulence in plants. However, the mechanisms by which ACs determine specific traits associated with lifestyle transitions along a symbiotic continuum are not clear. Here we delineated the genetic divergence in two sympatric but considerably variable isolates (16B and 16W) of the poplar-associated fungus Stagonosporopsis rhizophilae. We identified a ∼0.6-Mb horizontally acquired AC in 16W that resulted in a mildly parasitic lifestyle in plants. Complete deletion of the AC (Δ16W) significantly altered the fungal phenotype. Specifically, Δ16W was morphologically more similar to 16B, showed enhanced melanization, and established beneficial interactions with poplar plants, thereby acting as a dark septate endophyte. RNA sequencing (RNA-seq) analysis showed that AC loss induced the upregulation of genes related to root colonization and biosynthesis of indole acetic acid and melanin. We observed that the AC maintained a more open status of chromatin across the genome, indicating an impressive remodeling of cis-regulatory elements upon AC loss, which potentially enhanced symbiotic effectiveness. We demonstrated that the symbiotic capacities were non-host-specific through comparable experiments on Triticum- and Arabidopsis-fungus associations. Furthermore, the three isolates generated symbiotic interactions with a nonvascular liverwort. In summary, our study suggests that the AC is a suppressor of symbiosis and provides insights into the underlying mechanisms of mutualism with vascular plants in the absence of traits encoded by the AC. We speculate that AC-situated effectors and other potential secreted molecules may have evolved to specifically target vascular plants and promote mild virulence.
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Affiliation(s)
- Huanshen Wei
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
| | - Zhenhui Zhong
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zhongfeng Li
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
| | - Yuwei Zhang
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
| | - Eva H Stukenbrock
- Environmental Genomics, Christian-Albrechts University, 24118 Kiel, Germany; Max Planck Fellow Group Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany.
| | - Boping Tang
- Jiangsu Key Laboratory for Bioresources of Saline Soils, School of Wetlands, Yancheng Teachers University, Yancheng 224002, China
| | - Ningning Yang
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
| | - Riccardo Baroncelli
- Department of Agricultural and Food Sciences (DISTAL), University of Bologna, 40127 Bologna, Italy
| | - Long Peng
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
| | - Zhuo Liu
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
| | - Xinghua He
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
| | - Yuzhan Yang
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
| | - Zhilin Yuan
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China.
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5
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Peng Y, Song W, Teif VB, Ovcharenko I, Landsman D, Panchenko AR. Detection of new pioneer transcription factors as cell-type specific nucleosome binders. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.10.540098. [PMID: 37425841 PMCID: PMC10327179 DOI: 10.1101/2023.05.10.540098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Wrapping of DNA into nucleosomes restricts accessibility to the DNA and may affect the recognition of binding motifs by transcription factors. A certain class of transcription factors, the pioneer transcription factors, can specifically recognize their DNA binding sites on nucleosomes, may initiate local chromatin opening and facilitate the binding of co-factors in a cell-type-specific manner. For the majority of human pioneer transcription factors, the locations of their binding sites, mechanisms of binding and regulation remain unknown. We have developed a computational method to predict the cell-type-specific ability of transcription factors to bind nucleosomes by integrating ChIP-seq, MNase-seq and DNase-seq data with details of nucleosome structure. We have demonstrated the ability of our approach in discriminating pioneer from canonical transcription factors and predicted new potential pioneer transcription factors in H1, K562, HepG2 and HeLa cell lines. Lastly, we systemically analyzed the interaction modes between various pioneer transcription factors and detected several clusters of distinctive binding sites on nucleosomal DNA.
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Affiliation(s)
- Yunhui Peng
- current address: Institute of Biophysics and Department of Physics, Central China Normal University, Wuhan 430079, China
- National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Wei Song
- National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Vladimir B. Teif
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Ivan Ovcharenko
- National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - David Landsman
- National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Anna R. Panchenko
- Department of Pathology and Molecular Medicine, Queen’s University, ON, Canada
- Department of Biology and Molecular Sciences, Queen’s University, ON, Canada
- School of Computing, Queen’s University, ON, Canada
- Ontario Institute of Cancer Research, Toronto, ON, Canada
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6
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Wang R, Kumar B, Bhat-Nakshatri P, Khatpe AS, Murphy MP, Wanczyk KE, Simpson E, Chen D, Gao H, Liu Y, Doud EH, Mosley AL, Nakshatri H. A human skeletal muscle stem/myotube model reveals multiple signaling targets of cancer secretome in skeletal muscle. iScience 2023; 26:106541. [PMID: 37102148 PMCID: PMC10123345 DOI: 10.1016/j.isci.2023.106541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/16/2022] [Accepted: 03/24/2023] [Indexed: 04/03/2023] Open
Abstract
Skeletal muscle dysfunction or reprogramming due to the effects of the cancer secretome is observed in multiple malignancies. Although mouse models are routinely used to study skeletal muscle defects in cancer, because of species specificity of certain cytokines/chemokines in the secretome, a human model system is required. Here, we establish simplified multiple skeletal muscle stem cell lines (hMuSCs), which can be differentiated into myotubes. Using single nuclei ATAC-seq (snATAC-seq) and RNA-seq (snRNA-seq), we document chromatin accessibility and transcriptomic changes associated with the transition of hMuSCs to myotubes. Cancer secretome accelerated stem to myotube differentiation, altered the alternative splicing machinery and increased inflammatory, glucocorticoid receptor, and wound healing pathways in hMuSCs. Additionally, cancer secretome reduced metabolic and survival pathway associated miR-486, AKT, and p53 signaling in hMuSCs. hMuSCs underwent myotube differentiation when engrafted into NSG mice and thus providing a humanized in vivo skeletal muscle model system to study cancer cachexia.
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Affiliation(s)
- Ruizhong Wang
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Brijesh Kumar
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | | | - Aditi S. Khatpe
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Michael P. Murphy
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- VA Roudebush Medical Center, Indianapolis, IN 46202, USA
| | - Kristen E. Wanczyk
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- VA Roudebush Medical Center, Indianapolis, IN 46202, USA
| | - Edward Simpson
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Duojiao Chen
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Hongyu Gao
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yunlong Liu
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Emma H. Doud
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Amber L. Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Harikrishna Nakshatri
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- VA Roudebush Medical Center, Indianapolis, IN 46202, USA
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So J, Taleb S, Wann J, Strobel O, Kim K, Roh HC. Chronic cAMP activation induces adipocyte browning through discordant biphasic remodeling of transcriptome and chromatin accessibility. Mol Metab 2022; 66:101619. [PMID: 36273781 PMCID: PMC9636484 DOI: 10.1016/j.molmet.2022.101619] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/11/2022] [Accepted: 10/18/2022] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVE Adipose tissue thermogenesis has been suggested as a new therapeutic target to promote energy metabolism for obesity and metabolic disease. Cold-inducible thermogenic adipocytes, called beige adipocytes, have attracted significant attention for their potent anti-obesity activity in adult humans. In this study, we identified the mechanisms underlying beige adipocyte recruitment, so-called adipocyte browning, by different stimuli. METHODS We generated a new adipocyte cell line with enhanced browning potentials and determined its transcriptomic and epigenomic responses following cAMP (forskolin, FSK) versus PPARγ activation (rosiglitazone). We performed time-course RNA-seq and compared the treatments and in vivo adipocyte browning. We also developed an improved protocol for Assay for Transposase Accessible Chromatin-sequencing (ATAC-seq) and defined changes in chromatin accessibility in a time course. The RNA-seq and ATAC-seq data were integrated to determine the kinetics of their coordinated regulation and to identify a transcription factor that drives these processes. We conducted functional studies using pharmacological and genetic approaches with specific inhibitors and shRNA-mediated knockdown, respectively. RESULTS FSK, not rosiglitazone, resulted in a biphasic transcriptomic response, resembling the kinetics of in vivo cold-induced browning. FSK promoted tissue remodeling first and subsequently shifted energy metabolism, concluding with a transcriptomic profile similar to that induced by rosiglitazone. The thermogenic effects of FSK were abolished by PPARγ antagonists, indicating PPARγ as a converging point. ATAC-seq uncovered that FSK leads to a significant chromatin remodeling that precedes or persists beyond transcriptomic changes, whereas rosiglitazone induces minimal changes. Motif analysis identified nuclear factor, interleukin 3 regulated (NFIL3) as a transcriptional regulator connecting the biphasic response of FSK-induced browning, as indicated by disrupted thermogenesis with NFIL3 knockdown. CONCLUSIONS Our findings elucidated unique dynamics of the transcriptomic and epigenomic remodeling in adipocyte browning, providing new mechanistic insights into adipose thermogenesis and molecular targets for obesity treatment.
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The Estrogen Receptor α Signaling Pathway Controls Alternative Splicing in the Absence of Ligands in Breast Cancer Cells. Cancers (Basel) 2021; 13:cancers13246261. [PMID: 34944881 PMCID: PMC8699117 DOI: 10.3390/cancers13246261] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/30/2021] [Accepted: 12/10/2021] [Indexed: 12/21/2022] Open
Abstract
Background: The transcriptional activity of estrogen receptor α (ERα) in breast cancer (BC) is extensively characterized. Our group has previously shown that ERα controls the expression of a number of genes in its unliganded form (apoERα), among which a large group of RNA-binding proteins (RBPs) encode genes, suggesting its role in the control of co- and post-transcriptional events. Methods: apoERα-mediated RNA processing events were characterized by the analysis of transcript usage and alternative splicing changes in an RNA-sequencing dataset from MCF-7 cells after siRNA-induced ERα downregulation. Results: ApoERα depletion induced an expression change of 681 RBPs, including 84 splicing factors involved in translation, ribonucleoprotein complex assembly, and 3′end processing. ApoERα depletion results in 758 isoform switching events with effects on 3′end length and the splicing of alternative cassette exons. The functional enrichment of these events shows that post-transcriptional regulation is part of the mechanisms by which apoERα controls epithelial-to-mesenchymal transition and BC cell proliferation. In primary BCs, the inclusion levels of the experimentally identified alternatively spliced exons are associated with overall and disease-free survival. Conclusion: Our data supports the role of apoERα in maintaining the luminal phenotype of BC cells by extensively regulating gene expression at the alternative splicing level.
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Khatpe AS, Adebayo AK, Herodotou CA, Kumar B, Nakshatri H. Nexus between PI3K/AKT and Estrogen Receptor Signaling in Breast Cancer. Cancers (Basel) 2021; 13:369. [PMID: 33498407 PMCID: PMC7864210 DOI: 10.3390/cancers13030369] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 12/12/2022] Open
Abstract
Signaling from estrogen receptor alpha (ERα) and its ligand estradiol (E2) is critical for growth of ≈70% of breast cancers. Therefore, several drugs that inhibit ERα functions have been in clinical use for decades and new classes of anti-estrogens are continuously being developed. Although a significant number of ERα+ breast cancers respond to anti-estrogen therapy, ≈30% of these breast cancers recur, sometimes even after 20 years of initial diagnosis. Mechanism of resistance to anti-estrogens is one of the intensely studied disciplines in breast cancer. Several mechanisms have been proposed including mutations in ESR1, crosstalk between growth factor and ERα signaling, and interplay between cell cycle machinery and ERα signaling. ESR1 mutations as well as crosstalk with other signaling networks lead to ligand independent activation of ERα thus rendering anti-estrogens ineffective, particularly when treatment involved anti-estrogens that do not degrade ERα. As a result of these studies, several therapies that combine anti-estrogens that degrade ERα with PI3K/AKT/mTOR inhibitors targeting growth factor signaling or CDK4/6 inhibitors targeting cell cycle machinery are used clinically to treat recurrent ERα+ breast cancers. In this review, we discuss the nexus between ERα-PI3K/AKT/mTOR pathways and how understanding of this nexus has helped to develop combination therapies.
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Affiliation(s)
- Aditi S. Khatpe
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (A.S.K.); (A.K.A.); (C.A.H.); (B.K.)
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Adedeji K. Adebayo
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (A.S.K.); (A.K.A.); (C.A.H.); (B.K.)
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Christopher A. Herodotou
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (A.S.K.); (A.K.A.); (C.A.H.); (B.K.)
| | - Brijesh Kumar
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (A.S.K.); (A.K.A.); (C.A.H.); (B.K.)
| | - Harikrishna Nakshatri
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (A.S.K.); (A.K.A.); (C.A.H.); (B.K.)
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- VA Roudebush Medical Center, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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