1
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Teufelsbauer M, Stickler S, Eggerstorfer MT, Hammond DC, Hamilton G. BET-directed PROTACs in triple negative breast cancer cell lines MDA-MB-231 and MDA-MB-436. Breast Cancer Res Treat 2024:10.1007/s10549-024-07403-w. [PMID: 38896334 DOI: 10.1007/s10549-024-07403-w] [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: 05/17/2024] [Accepted: 06/09/2024] [Indexed: 06/21/2024]
Abstract
PURPOSE This study aims to find whether the proliferation and migration of triple negative breast cancer (TNBC) cell lines can be reduced by treatment with bromodomain and extra-terminal domain (BET) inhibitor JQ1 and BET protein targeting chimeras (PROTACs) ARV-771 and MZ1. METHODS Cytotoxicity tests, scratch migration assays and western blot proteome profiler arrays for protein expression of cancer-related proteins were used to evaluate the impact of a BET-inhibitor and two BET-directed PROTACs on cell viability, migration and on protein expression. RESULTS JQ1 and the PROTACs MZ1 and ARV-771 significantly inhibited the growth and migration of the KRAS G13D-mutated MDA-MB-231 cells. In this cell line, the PROTACs suppressed the residual expression of ERBB2/HER2, 3 and 4 that are essential for the proliferation of breast cancer cells and this cell line proved sensitive to HER2 inhibitors. In contrast, the effects of the PROTACs on the protein expression of MDA-MB-436 cells mostly affected cytokines and their cognate receptors. CONCLUSION The degradation of BET-protein by PROTACs demonstrated significant anti-proliferative effects. The KRAS-mutated MDA-MB-231 cells belong to the low-HER2 expressing tumors that have a poorer prognosis compared to HER2-null patients. Since first oral PROTACs against tumor hormone receptors are in clinical trials, this mode of tumor therapy is expected to become an important therapeutic strategy in the future treatment of TNBC.
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Affiliation(s)
- Maryana Teufelsbauer
- Clinics of Plastic and Reconstructive Surgery, Medical University of Vienna, Vienna, Austria
| | - Sandra Stickler
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | | | | | - Gerhard Hamilton
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria.
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2
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Woodworth AM, Hardy K, Taberlay PC, Dickinson JL, Holloway AF. RUNX1 regulates promoter activity in the absence of cognate DNA binding motifs. J Cell Biochem 2024; 125:e30570. [PMID: 38616697 DOI: 10.1002/jcb.30570] [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: 12/21/2023] [Revised: 03/29/2024] [Accepted: 04/06/2024] [Indexed: 04/16/2024]
Abstract
Runt-related transcription factor 1 (RUNX1) plays an important role in normal haematopoietic cell development and function, and its function is frequently disrupted in leukaemia. RUNX1 is widely recognised as a sequence-specific DNA binding factor that recognises the motif 5'-TG(T/C)GGT-3' in promoter and enhancer regions of its target genes. Moreover, RUNX1 fusion proteins, such as RUNX1-ETO formed by the t(8;21) translocation, retain the ability to recognise and bind to this sequence to elicit atypical gene regulatory effects on bona fide RUNX1 targets. However, our analysis of publicly available RUNX1 chromatin immunoprecipitation sequencing (ChIP-Seq) data has provided evidence challenging this dogma, revealing that this motif-specific model of RUNX1 recruitment and function is incomplete. Our analyses revealed that the majority of RUNX1 genomic localisation occurs outside of promoters, that 20% of RUNX1 binding sites lack consensus RUNX motifs, and that binding in the absence of a cognate binding site is more common in promoter regions compared to distal sites. Reporter assays demonstrate that RUNX1 can drive promoter activity in the absence of a recognised DNA binding motif, in contrast to RUNX1-ETO. RUNX1-ETO supresses activity when it is recruited to promoters containing a sequence specific motif, while interestingly, it binds but does not repress promoters devoid of a RUNX1 recognition site. These data suggest that RUNX1 regulation of target genes occurs through multiple mechanisms depending on genomic location, the type of regulatory element and mode of recruitment.
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Affiliation(s)
- Alex M Woodworth
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Kristine Hardy
- Faculty of Education, Science, Technology and Mathematics, Discipline of Biomedical Science, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Phillippa C Taberlay
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Joanne L Dickinson
- Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Adele F Holloway
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
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3
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Schütz S, Bergsdorf C, Hänni-Holzinger S, Lingel A, Renatus M, Gossert AD, Jahnke W. Intrinsically Disordered Regions in the Transcription Factor MYC:MAX Modulate DNA Binding via Intramolecular Interactions. Biochemistry 2024. [PMID: 38264995 DOI: 10.1021/acs.biochem.3c00608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
The basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factor (TF) MYC is in large part an intrinsically disordered oncoprotein. In complex with its obligate heterodimerization partner MAX, MYC preferentially binds E-Box DNA sequences (CANNTG). At promoters containing these sequence motifs, MYC controls fundamental cellular processes such as cell cycle progression, metabolism, and apoptosis. A vast network of proteins in turn regulates MYC function via intermolecular interactions. In this work, we establish another layer of MYC regulation by intramolecular interactions. We used nuclear magnetic resonance (NMR) spectroscopy to identify and map multiple binding sites for the C-terminal MYC:MAX DNA-binding domain (DBD) on the intrinsically disordered regions (IDRs) in the MYC N-terminus. We find that these binding events in trans are driven by electrostatic attraction, that they have distinct affinities, and that they are competitive with DNA binding. Thereby, we observe the strongest effects for the N-terminal MYC box 0 (Mb0), a conserved motif involved in MYC transactivation and target gene induction. We prepared recombinant full-length MYC:MAX complex and demonstrate that the interactions identified in this work are also relevant in cis, i.e., as intramolecular interactions. These findings are supported by surface plasmon resonance (SPR) experiments, which revealed that intramolecular IDR:DBD interactions in MYC decelerate the association of MYC:MAX complexes to DNA. Our work offers new insights into how bHLH-LZ TFs are regulated by intramolecular interactions, which open up new possibilities for drug discovery.
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Affiliation(s)
- Stefan Schütz
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Christian Bergsdorf
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Sandra Hänni-Holzinger
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Andreas Lingel
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Martin Renatus
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | | | - Wolfgang Jahnke
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
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4
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Wu G, Qin S, Gu K, Zhou Y. PYCR2, induced by c-Myc, promotes the invasiveness and metastasis of breast cancer by activating AKT signalling pathway. Int J Biochem Cell Biol 2024; 166:106506. [PMID: 38101533 DOI: 10.1016/j.biocel.2023.106506] [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: 08/08/2023] [Revised: 11/17/2023] [Accepted: 12/11/2023] [Indexed: 12/17/2023]
Abstract
BACKGROUND Pyrroline-5-carboxylate reductase 2 (PYCR2) expression is aberrantly upregulated in colon cancer. However, the functions and underlying mechanisms of PYCR2 in breast cancer remain elusive. The primary objective of the present study was to elucidate the function of PYCR2 in breast cancer and investigate whether PYCR2 may be transcriptionally regulated by c-Myc to activate the AKT signaling pathway. METHODS Immunohistochemical analysis was performed to examine the expression of PYCR2 in breast cancer and adjacent non-cancerous tissues. Western blot and RT-qPCR were utilized to detect PYCR2 expression in breast cancer cells. Cellular functionalities were evaluated through Transwell assays in vitro and lung metastasis formation assays in vivo. Moreover, the impact of PYCR2 on the activation of AKT signaling was determined through western blot and immunohistochemistry analysis. The transcriptional regulation of PYCR2 expression by c-Myc was evaluated via both western blot analysis and luciferase gene reporter assay. RESULTS PYCR2 overexpression was noted in breast cancer. Silencing PYCR2 expression attenuated the invasive and metastatic abilities of breast cancer cells. Furthermore, the activation of the AKT signaling pathway is indispensable for the promotion of invasion and metastasis mediated by PYCR2. Lastly, the binding of c-Myc to the promoter sequence of PYCR2 resulted in the upregulation of PYCR2 transcription. CONCLUSION Taken together, these results indicate that PYCR2 is transcriptionally regulated by c-Myc and promotes invasion and metastasis in breast cancer through the activation of the AKT pathway.
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Affiliation(s)
- Gang Wu
- Department of Radiotherapy and Oncology, The Affiliated Hospital of Jiangnan University, Wuxi 214062, China.
| | | | - Ke Gu
- Department of Radiotherapy and Oncology, The Affiliated Hospital of Jiangnan University, Wuxi 214062, China.
| | - Yanjun Zhou
- Department of Radiotherapy and Oncology, The Affiliated Hospital of Jiangnan University, Wuxi 214062, China.
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5
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Measuring the impact of chromatin context on transcription factor binding affinities. Nat Biotechnol 2023; 41:1696-1697. [PMID: 36973560 DOI: 10.1038/s41587-023-01752-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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6
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Liu F, Liao Z, Zhang Z. MYC in liver cancer: mechanisms and targeted therapy opportunities. Oncogene 2023; 42:3303-3318. [PMID: 37833558 DOI: 10.1038/s41388-023-02861-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/28/2023] [Accepted: 10/03/2023] [Indexed: 10/15/2023]
Abstract
MYC, a major oncogenic transcription factor, regulates target genes involved in various pathways such as cell proliferation, metabolism and immune evasion, playing a critical role in the tumor initiation and development in multiple types of cancer. In liver cancer, MYC and its signaling pathways undergo significant changes, exerting a profound impact on liver cancer progression, including tumor proliferation, metastasis, dedifferentiation, metabolism, immune microenvironment, and resistance to comprehensive therapies. This makes MYC an appealing target, despite it being previously considered an undruggable protein. In this review, we discuss the role and mechanisms of MYC in liver physiology, chronic liver diseases, hepatocarcinogenesis, and liver cancer progression, providing a theoretical basis for targeting MYC as an ideal therapeutic target for liver cancer. We also summarize and prospect the strategies for targeting MYC, including direct and indirect approaches to abolish the oncogenic function of MYC in liver cancer.
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Affiliation(s)
- Furong Liu
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
- Hubei Key Laboratory of Hepato-Pancreato-Biliary Diseases, Wuhan, Hubei, 430030, China
- Key Laboratory of Organ Transplantation, Ministry of Education; NHC Key Laboratory of Organ Transplantation; Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China
| | - Zhibin Liao
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
- Hubei Key Laboratory of Hepato-Pancreato-Biliary Diseases, Wuhan, Hubei, 430030, China
- Key Laboratory of Organ Transplantation, Ministry of Education; NHC Key Laboratory of Organ Transplantation; Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China
| | - Zhanguo Zhang
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China.
- Hubei Key Laboratory of Hepato-Pancreato-Biliary Diseases, Wuhan, Hubei, 430030, China.
- Key Laboratory of Organ Transplantation, Ministry of Education; NHC Key Laboratory of Organ Transplantation; Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China.
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7
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Jha RK, Kouzine F, Levens D. MYC function and regulation in physiological perspective. Front Cell Dev Biol 2023; 11:1268275. [PMID: 37941901 PMCID: PMC10627926 DOI: 10.3389/fcell.2023.1268275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 10/12/2023] [Indexed: 11/10/2023] Open
Abstract
MYC, a key member of the Myc-proto-oncogene family, is a universal transcription amplifier that regulates almost every physiological process in a cell including cell cycle, proliferation, metabolism, differentiation, and apoptosis. MYC interacts with several cofactors, chromatin modifiers, and regulators to direct gene expression. MYC levels are tightly regulated, and deregulation of MYC has been associated with numerous diseases including cancer. Understanding the comprehensive biology of MYC under physiological conditions is an utmost necessity to demark biological functions of MYC from its pathological functions. Here we review the recent advances in biological mechanisms, functions, and regulation of MYC. We also emphasize the role of MYC as a global transcription amplifier.
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Affiliation(s)
| | | | - David Levens
- Gene Regulation Section, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute (NCI), Bethesda, MD, United States
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8
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Pan Y, van der Watt PJ, Kay SA. E-box binding transcription factors in cancer. Front Oncol 2023; 13:1223208. [PMID: 37601651 PMCID: PMC10437117 DOI: 10.3389/fonc.2023.1223208] [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: 05/15/2023] [Accepted: 06/27/2023] [Indexed: 08/22/2023] Open
Abstract
E-boxes are important regulatory elements in the eukaryotic genome. Transcription factors can bind to E-boxes through their basic helix-loop-helix or zinc finger domain to regulate gene transcription. E-box-binding transcription factors (EBTFs) are important regulators of development and essential for physiological activities of the cell. The fundamental role of EBTFs in cancer has been highlighted by studies on the canonical oncogene MYC, yet many EBTFs exhibit common features, implying the existence of shared molecular principles of how they are involved in tumorigenesis. A comprehensive analysis of TFs that share the basic function of binding to E-boxes has been lacking. Here, we review the structure of EBTFs, their common features in regulating transcription, their physiological functions, and their mutual regulation. We also discuss their converging functions in cancer biology, their potential to be targeted as a regulatory network, and recent progress in drug development targeting these factors in cancer therapy.
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Affiliation(s)
- Yuanzhong Pan
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Pauline J. van der Watt
- Division of Medical Biochemistry and Structural Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Steve A. Kay
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
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9
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Speltz TE, Qiao Z, Swenson CS, Shangguan X, Coukos JS, Lee CW, Thomas DM, Santana J, Fanning SW, Greene GL, Moellering RE. Targeting MYC with modular synthetic transcriptional repressors derived from bHLH DNA-binding domains. Nat Biotechnol 2023; 41:541-551. [PMID: 36302987 PMCID: PMC10392954 DOI: 10.1038/s41587-022-01504-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 09/08/2022] [Indexed: 01/16/2023]
Abstract
Despite unequivocal roles in disease, transcription factors (TFs) remain largely untapped as pharmacologic targets due to the challenges in targeting protein-protein and protein-DNA interactions. Here we report a chemical strategy to generate modular synthetic transcriptional repressors (STRs) derived from the bHLH domain of MAX. Our synthetic approach yields chemically stabilized tertiary domain mimetics that cooperatively bind the MYC/MAX consensus E-box motif with nanomolar affinity, exhibit specificity that is equivalent to or beyond that of full-length TFs and directly compete with MYC/MAX protein for DNA binding. A lead STR directly inhibits MYC binding in cells, downregulates MYC-dependent expression programs at the proteome level and inhibits MYC-dependent cell proliferation. Co-crystallization and structure determination of a STR:E-box DNA complex confirms retention of DNA recognition in a near identical manner as full-length bHLH TFs. We additionally demonstrate structure-blind design of STRs derived from alternative bHLH-TFs, confirming that STRs can be used to develop highly specific mimetics of TFs targeting other gene regulatory elements.
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Affiliation(s)
- Thomas E Speltz
- Department of Chemistry, University of Chicago, Chicago, IL, USA
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL, USA
| | - Zeyu Qiao
- Department of Chemistry, University of Chicago, Chicago, IL, USA
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL, USA
| | - Colin S Swenson
- Department of Chemistry, University of Chicago, Chicago, IL, USA
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL, USA
| | - Xianghang Shangguan
- Department of Chemistry, University of Chicago, Chicago, IL, USA
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL, USA
| | - John S Coukos
- Department of Chemistry, University of Chicago, Chicago, IL, USA
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL, USA
| | - Christopher W Lee
- Department of Chemistry, University of Chicago, Chicago, IL, USA
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL, USA
| | - Deborah M Thomas
- Department of Chemistry, University of Chicago, Chicago, IL, USA
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL, USA
| | - Jesse Santana
- Department of Chemistry, University of Chicago, Chicago, IL, USA
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL, USA
| | - Sean W Fanning
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL, USA
- Department of Cancer Biology, Loyola University Chicago, Chicago, IL, USA
| | - Geoffrey L Greene
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL, USA
| | - Raymond E Moellering
- Department of Chemistry, University of Chicago, Chicago, IL, USA.
- Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL, USA.
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10
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Scagnoli F, Palma A, Favia A, Scuoppo C, Illi B, Nasi S. A New Insight into MYC Action: Control of RNA Polymerase II Methylation and Transcription Termination. Biomedicines 2023; 11:biomedicines11020412. [PMID: 36830948 PMCID: PMC9952900 DOI: 10.3390/biomedicines11020412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/16/2023] [Accepted: 01/26/2023] [Indexed: 02/01/2023] Open
Abstract
MYC oncoprotein deregulation is a common catastrophic event in human cancer and limiting its activity restrains tumor development and maintenance, as clearly shown via Omomyc, an MYC-interfering 90 amino acid mini-protein. MYC is a multifunctional transcription factor that regulates many aspects of transcription by RNA polymerase II (RNAPII), such as transcription activation, pause release, and elongation. MYC directly associates with Protein Arginine Methyltransferase 5 (PRMT5), a protein that methylates a variety of targets, including RNAPII at the arginine residue R1810 (R1810me2s), crucial for proper transcription termination and splicing of transcripts. Therefore, we asked whether MYC controls termination as well, by affecting R1810me2S. We show that MYC overexpression strongly increases R1810me2s, while Omomyc, an MYC shRNA, or a PRMT5 inhibitor and siRNA counteract this phenomenon. Omomyc also impairs Serine 2 phosphorylation in the RNAPII carboxyterminal domain, a modification that sustains transcription elongation. ChIP-seq experiments show that Omomyc replaces MYC and reshapes RNAPII distribution, increasing occupancy at promoter and termination sites. It is unclear how this may affect gene expression. Transcriptomic analysis shows that transcripts pivotal to key signaling pathways are both up- or down-regulated by Omomyc, whereas genes directly controlled by MYC and belonging to a specific signature are strongly down-regulated. Overall, our data point to an MYC/PRMT5/RNAPII axis that controls termination via RNAPII symmetrical dimethylation and contributes to rewiring the expression of genes altered by MYC overexpression in cancer cells. It remains to be clarified which role this may have in tumor development.
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Affiliation(s)
- Fiorella Scagnoli
- IBPM—CNR, Biology and Biotechnology Department, Sapienza University, 00185 Rome, Italy
- Correspondence: (F.S.); (B.I.); (S.N.)
| | - Alessandro Palma
- Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy
| | - Annarita Favia
- IBPM—CNR, Biology and Biotechnology Department, Sapienza University, 00185 Rome, Italy
| | - Claudio Scuoppo
- Institute for Cancer Genetics, Columbia University, New York, NY 10032, USA
| | - Barbara Illi
- IBPM—CNR, Biology and Biotechnology Department, Sapienza University, 00185 Rome, Italy
- Correspondence: (F.S.); (B.I.); (S.N.)
| | - Sergio Nasi
- IBPM—CNR, Biology and Biotechnology Department, Sapienza University, 00185 Rome, Italy
- Correspondence: (F.S.); (B.I.); (S.N.)
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11
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Fioresi R, Demurtas P, Perini G. Deep learning for MYC binding site recognition. FRONTIERS IN BIOINFORMATICS 2022; 2:1015993. [PMID: 36544623 PMCID: PMC9760990 DOI: 10.3389/fbinf.2022.1015993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 11/24/2022] [Indexed: 12/07/2022] Open
Abstract
Motivation: The definition of the genome distribution of the Myc transcription factor is extremely important since it may help predict its transcriptional activity particularly in the context of cancer. Myc is among the most powerful oncogenes involved in the occurrence and development of more than 80% of different types of pediatric and adult cancers. Myc regulates thousands of genes which can be in part different, depending on the type of tissues and tumours. Myc distribution along the genome has been determined experimentally through chromatin immunoprecipitation This approach, although powerful, is very time consuming and cannot be routinely applied to tumours of individual patients. Thus, it becomes of paramount importance to develop in silico tools that can effectively and rapidly predict its distribution on a given cell genome. New advanced computational tools (DeeperBind) can then be successfully employed to determine the function of Myc in a specific tumour, and may help to devise new directions and approaches to experiments first and personalized and more effective therapeutic treatments for a single patient later on. Results: The use of DeeperBind with DeepRAM on Colab platform (Google) can effectively predict the binding sites for the MYC factor with an accuracy above 0.96 AUC, when trained with multiple cell lines. The analysis of the filters in DeeperBind trained models shows, besides the consensus sequence CACGTG classically associated to the MYC factor, also the other consensus sequences G/C box or TGGGA, respectively bound by the SP1 and MIZ-1 transcription factors, which are known to mediate the MYC repressive response. Overall, our findings suggest a stronger synergy between the machine learning tools as DeeperBind and biological experiments, which may reduce the time consuming experiments by providing a direction to guide them.
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12
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Schütz S, Bergsdorf C, Goretzki B, Lingel A, Renatus M, Gossert AD, Jahnke W. The disordered MAX N-terminus modulates DNA binding of the transcription factor MYC:MAX. J Mol Biol 2022; 434:167833. [PMID: 36174765 DOI: 10.1016/j.jmb.2022.167833] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/05/2022] [Accepted: 09/17/2022] [Indexed: 11/15/2022]
Abstract
The intrinsically disordered protein MYC belongs to the family of basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factors (TFs). In complex with its cognate binding partner MAX, MYC preferentially binds to E-Box promotor sequences where it controls fundamental cellular processes such as cell cycle progression, metabolism, and apoptosis. Intramolecular regulation of MYC:MAX has not yet been investigated in detail. In this work, we use Nuclear Magnetic Resonance (NMR) spectroscopy to identify and map interactions between the disordered MAX N-terminus and the MYC:MAX DNA binding domain (DBD). We find that this binding event is mainly driven by electrostatic interactions and that it is competitive with DNA binding. Using Nuclear Magnetic resonance (NMR) spectroscopy and Surface Plasmon Resonance (SPR), we demonstrate that the MAX N-terminus serves to accelerate DNA binding kinetics of MYC:MAX and MAX:MAX dimers, while it simultaneously provides specificity for E-Box DNA. We also establish that these effects are further enhanced by Casein Kinase 2-mediated phosphorylation of two serine residues in the MAX N-terminus. Our work provides new insights how bHLH-LZ TFs are regulated by intramolecular interactions between disordered regions and the folded DNA binding domain.
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Affiliation(s)
- Stefan Schütz
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Christian Bergsdorf
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Benedikt Goretzki
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Andreas Lingel
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Martin Renatus
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Alvar D Gossert
- Department of Biology, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Wolfgang Jahnke
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland.
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13
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EZH2 noncanonically binds cMyc and p300 through a cryptic transactivation domain to mediate gene activation and promote oncogenesis. Nat Cell Biol 2022; 24:384-399. [PMID: 35210568 PMCID: PMC9710513 DOI: 10.1038/s41556-022-00850-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 01/14/2022] [Indexed: 12/20/2022]
Abstract
Canonically, EZH2 serves as the catalytic subunit of PRC2, which mediates H3K27me3 deposition and transcriptional repression. Here, we report that in acute leukaemias, EZH2 has additional noncanonical functions by binding cMyc at non-PRC2 targets and uses a hidden transactivation domain (TAD) for (co)activator recruitment and gene activation. Both canonical (EZH2-PRC2) and noncanonical (EZH2-TAD-cMyc-coactivators) activities of EZH2 promote oncogenesis, which explains the slow and ineffective antitumour effect of inhibitors of the catalytic function of EZH2. To suppress the multifaceted activities of EZH2, we used proteolysis-targeting chimera (PROTAC) to develop a degrader, MS177, which achieved effective, on-target depletion of EZH2 and interacting partners (that is, both canonical EZH2-PRC2 and noncanonical EZH2-cMyc complexes). Compared with inhibitors of the enzymatic function of EZH2, MS177 is fast-acting and more potent in suppressing cancer growth. This study reveals noncanonical oncogenic roles of EZH2, reports a PROTAC for targeting the multifaceted tumorigenic functions of EZH2 and presents an attractive strategy for treating EZH2-dependent cancers.
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14
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Das SK, Kuzin V, Cameron DP, Sanford S, Jha RK, Nie Z, Rosello MT, Holewinski R, Andresson T, Wisniewski J, Natsume T, Price DH, Lewis BA, Kouzine F, Levens D, Baranello L. MYC assembles and stimulates topoisomerases 1 and 2 in a "topoisome". Mol Cell 2021; 82:140-158.e12. [PMID: 34890565 DOI: 10.1016/j.molcel.2021.11.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 08/11/2021] [Accepted: 11/13/2021] [Indexed: 12/25/2022]
Abstract
High-intensity transcription and replication supercoil DNA to levels that can impede or halt these processes. As a potent transcription amplifier and replication accelerator, the proto-oncogene MYC must manage this interfering torsional stress. By comparing gene expression with the recruitment of topoisomerases and MYC to promoters, we surmised a direct association of MYC with topoisomerase 1 (TOP1) and TOP2 that was confirmed in vitro and in cells. Beyond recruiting topoisomerases, MYC directly stimulates their activities. We identify a MYC-nucleated "topoisome" complex that unites TOP1 and TOP2 and increases their levels and activities at promoters, gene bodies, and enhancers. Whether TOP2A or TOP2B is included in the topoisome is dictated by the presence of MYC versus MYCN, respectively. Thus, in vitro and in cells, MYC assembles tools that simplify DNA topology and promote genome function under high output conditions.
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Affiliation(s)
- Subhendu K Das
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - Vladislav Kuzin
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Donald P Cameron
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Suzanne Sanford
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - Rajiv Kumar Jha
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - Zuqin Nie
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - Marta Trullols Rosello
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Ronald Holewinski
- Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Bethesda, MD 21701, USA
| | - Thorkell Andresson
- Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Bethesda, MD 21701, USA
| | - Jan Wisniewski
- Confocal Microscopy and Digital Imaging Facility, National Cancer Institute, Bethesda, MD 20892, USA
| | - Toyoaki Natsume
- Department of Chromosome Science, National Institute of Genetics, Shizuoka 411-8540, Japan; Research Center for Genome & Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - David H Price
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Brian A Lewis
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - Fedor Kouzine
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - David Levens
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA.
| | - Laura Baranello
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden.
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15
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Differential Transcriptional Reprogramming by Wild Type and Lymphoma-Associated Mutant MYC Proteins as B-Cells Convert to a Lymphoma Phenotype. Cancers (Basel) 2021; 13:cancers13236093. [PMID: 34885204 PMCID: PMC8657136 DOI: 10.3390/cancers13236093] [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: 10/27/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 11/16/2022] Open
Abstract
The MYC transcription factor regulates a vast number of genes and is implicated in many human malignancies. In some hematological malignancies, MYC is frequently subject to missense mutations that enhance its transformation activity. Here, we use a novel murine cell system to (i) characterize the transcriptional effects of progressively increasing MYC levels as normal primary B-cells transform to lymphoma cells and (ii) determine how this gene regulation program is modified by lymphoma-associated MYC mutations (T58A and T58I) that enhance its transformation activity. Unlike many previous studies, the cell system exploits primary B-cells that are transduced to allow regulated MYC expression under circumstances where apoptosis and senescence pathways are abrogated by the over-expression of the Bcl-xL and BMI1 proteins. In such cells, transition from a normal to a lymphoma phenotype is directly dependent on the MYC expression level, without a requirement for secondary events that are normally required during MYC-driven oncogenic transformation. A generalized linear model approach allowed an integrated analysis of RNA sequencing data to identify regulated genes in relation to both progressively increasing MYC level and wild type or mutant status. Using this design, a total of 7569 regulated genes were identified, of which the majority (n = 7263) were regulated in response to progressively increased levels of wild type MYC, while a smaller number of genes (n = 917) were differentially regulated, compared to wild type MYC, in T58A MYC- and/or T58I MYC-expressing cells. Unlike most genes that are similarly regulated by both wild type and mutant MYC genes, the set of 917 genes did not significantly overlap with known lipopolysaccharide regulated genes, which represent genes regulated by MYC in normal B cells. The genes that were differently regulated in cells expressing mutant MYC proteins were significantly enriched in DNA replication and G2 phase to mitosis transition genes. Thus, mutants affecting MYC proteins may augment quantitative oncogenic effects on the expression of normal MYC-target genes with qualitative oncogenic effects, by which sets of cell cycle genes are abnormally targeted by MYC as B cells transition into lymphoma cells. The T58A and T58I mutations augment MYC-driven transformation by distinct mechanisms.
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16
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Lourenco C, Resetca D, Redel C, Lin P, MacDonald AS, Ciaccio R, Kenney TMG, Wei Y, Andrews DW, Sunnerhagen M, Arrowsmith CH, Raught B, Penn LZ. MYC protein interactors in gene transcription and cancer. Nat Rev Cancer 2021; 21:579-591. [PMID: 34188192 DOI: 10.1038/s41568-021-00367-9] [Citation(s) in RCA: 130] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/04/2021] [Indexed: 02/07/2023]
Abstract
The transcription factor and oncoprotein MYC is a potent driver of many human cancers and can regulate numerous biological activities that contribute to tumorigenesis. How a single transcription factor can regulate such a diverse set of biological programmes is central to the understanding of MYC function in cancer. In this Perspective, we highlight how multiple proteins that interact with MYC enable MYC to regulate several central control points of gene transcription. These include promoter binding, epigenetic modifications, initiation, elongation and post-transcriptional processes. Evidence shows that a combination of multiple protein interactions enables MYC to function as a potent oncoprotein, working together in a 'coalition model', as presented here. Moreover, as MYC depends on its protein interactome for function, we discuss recent research that emphasizes an unprecedented opportunity to target protein interactors to directly impede MYC oncogenesis.
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Affiliation(s)
| | - Diana Resetca
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Cornelia Redel
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Peter Lin
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Alannah S MacDonald
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Roberto Ciaccio
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Tristan M G Kenney
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Yong Wei
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - David W Andrews
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Maria Sunnerhagen
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Cheryl H Arrowsmith
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Structural Genomics Consortium, Toronto, ON, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Linda Z Penn
- Princess Margaret Cancer Centre, Toronto, ON, Canada.
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
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17
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Mechanisms of Binding Specificity among bHLH Transcription Factors. Int J Mol Sci 2021; 22:ijms22179150. [PMID: 34502060 PMCID: PMC8431614 DOI: 10.3390/ijms22179150] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/14/2021] [Accepted: 08/18/2021] [Indexed: 12/25/2022] Open
Abstract
The transcriptome of every cell is orchestrated by the complex network of interaction between transcription factors (TFs) and their binding sites on DNA. Disruption of this network can result in many forms of organism malfunction but also can be the substrate of positive natural selection. However, understanding the specific determinants of each of these individual TF-DNA interactions is a challenging task as it requires integrating the multiple possible mechanisms by which a given TF ends up interacting with a specific genomic region. These mechanisms include DNA motif preferences, which can be determined by nucleotide sequence but also by DNA’s shape; post-translational modifications of the TF, such as phosphorylation; and dimerization partners and co-factors, which can mediate multiple forms of direct or indirect cooperative binding. Binding can also be affected by epigenetic modifications of putative target regions, including DNA methylation and nucleosome occupancy. In this review, we describe how all these mechanisms have a role and crosstalk in one specific family of TFs, the basic helix-loop-helix (bHLH), with a very conserved DNA binding domain and a similar DNA preferred motif, the E-box. Here, we compile and discuss a rich catalog of strategies used by bHLH to acquire TF-specific genome-wide landscapes of binding sites.
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18
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Burchett JB, Knudsen-Clark AM, Altman BJ. MYC Ran Up the Clock: The Complex Interplay between MYC and the Molecular Circadian Clock in Cancer. Int J Mol Sci 2021; 22:7761. [PMID: 34299381 PMCID: PMC8305799 DOI: 10.3390/ijms22147761] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/02/2021] [Accepted: 07/14/2021] [Indexed: 12/13/2022] Open
Abstract
The MYC oncoprotein and its family members N-MYC and L-MYC are known to drive a wide variety of human cancers. Emerging evidence suggests that MYC has a bi-directional relationship with the molecular clock in cancer. The molecular clock is responsible for circadian (~24 h) rhythms in most eukaryotic cells and organisms, as a mechanism to adapt to light/dark cycles. Disruption of human circadian rhythms, such as through shift work, may serve as a risk factor for cancer, but connections with oncogenic drivers such as MYC were previously not well understood. In this review, we examine recent evidence that MYC in cancer cells can disrupt the molecular clock; and conversely, that molecular clock disruption in cancer can deregulate and elevate MYC. Since MYC and the molecular clock control many of the same processes, we then consider competition between MYC and the molecular clock in several select aspects of tumor biology, including chromatin state, global transcriptional profile, metabolic rewiring, and immune infiltrate in the tumor. Finally, we discuss how the molecular clock can be monitored or diagnosed in human tumors, and how MYC inhibition could potentially restore molecular clock function. Further study of the relationship between the molecular clock and MYC in cancer may reveal previously unsuspected vulnerabilities which could lead to new treatment strategies.
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Affiliation(s)
- Jamison B. Burchett
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642, USA;
| | - Amelia M. Knudsen-Clark
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA;
| | - Brian J. Altman
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642, USA;
- Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY 14642, USA
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19
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Figueiredo VC, Wen Y, Alkner B, Fernandez-Gonzalo R, Norrbom J, Vechetti IJ, Valentino T, Mobley CB, Zentner GE, Peterson CA, McCarthy JJ, Murach KA, von Walden F. Genetic and epigenetic regulation of skeletal muscle ribosome biogenesis with exercise. J Physiol 2021; 599:3363-3384. [PMID: 33913170 DOI: 10.1113/jp281244] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/20/2021] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Ribosome biogenesis and MYC transcription are associated with acute resistance exercise (RE) and are distinct from endurance exercise in human skeletal muscle throughout a 24 h time course of recovery. A PCR-based method for relative ribosomal DNA (rDNA) copy number estimation was validated by whole genome sequencing and revealed that rDNA dosage is positively correlated with ribosome biogenesis in response to RE. Acute RE modifies rDNA methylation patterns in enhancer, intergenic spacer and non-canonical MYC-associated regions, but not the promoter. Myonuclear-specific rDNA methylation patterns with acute mechanical overload in mice corroborate and expand on rDNA findings with RE in humans. A genetic predisposition for hypertrophic responsiveness may exist based on rDNA gene dosage. ABSTRACT Ribosomes are the macromolecular engines of protein synthesis. Skeletal muscle ribosome biogenesis is stimulated by exercise, although the contribution of ribosomal DNA (rDNA) copy number and methylation to exercise-induced rDNA transcription is unclear. To investigate the genetic and epigenetic regulation of ribosome biogenesis with exercise, a time course of skeletal muscle biopsies was obtained from 30 participants (18 men and 12 women; 31 ± 8 years, 25 ± 4 kg m-2 ) at rest and 30 min, 3 h, 8 h and 24 h after acute endurance (n = 10, 45 min cycling, 70% V ̇ O 2 max ) or resistance exercise (n = 10, 4 × 7 × 2 exercises); 10 control participants underwent biopsies without exercise. rDNA transcription and dosage were assessed using quantitative PCR and whole genome sequencing. rDNA promoter methylation was investigated using massARRAY EpiTYPER and global rDNA CpG methylation was assessed using reduced-representation bisulphite sequencing. Ribosome biogenesis and MYC transcription were associated primarily with resistance but not endurance exercise, indicating preferential up-regulation during hypertrophic processes. With resistance exercise, ribosome biogenesis was associated with rDNA gene dosage, as well as epigenetic changes in enhancer and non-canonical MYC-associated areas in rDNA, but not the promoter. A mouse model of in vivo metabolic RNA labelling and genetic myonuclear fluorescence labelling validated the effects of an acute hypertrophic stimulus on ribosome biogenesis and Myc transcription, and also corroborated rDNA enhancer and Myc-associated methylation alterations specifically in myonuclei. The present study provides the first information on skeletal muscle genetic and rDNA gene-wide epigenetic regulation of ribosome biogenesis in response to exercise, revealing novel roles for rDNA dosage and CpG methylation.
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Affiliation(s)
- Vandré C Figueiredo
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA.,The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Yuan Wen
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Björn Alkner
- Department of Orthopaedics, Eksjö, Region Jönköping County and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Rodrigo Fernandez-Gonzalo
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, and Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Jessica Norrbom
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Ivan J Vechetti
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Nutrition and Health Sciences, University of Nebraska, Lincoln, NE, USA
| | - Taylor Valentino
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - C Brooks Mobley
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | | | - Charlotte A Peterson
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA.,The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - John J McCarthy
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Kevin A Murach
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA.,The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Ferdinand von Walden
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA.,Division of Pediatric Neurology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
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20
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Marinkovic T, Marinkovic D. Obscure Involvement of MYC in Neurodegenerative Diseases and Neuronal Repair. Mol Neurobiol 2021; 58:4169-4177. [PMID: 33954904 DOI: 10.1007/s12035-021-02406-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/27/2021] [Indexed: 10/21/2022]
Abstract
MYC is well known as a potent oncogene involved in regulating cell cycle and metabolism. Augmented MYC expression leads to cell cycle dysregulation, intense cell proliferation, and carcinogenesis. Surprisingly, its increased expression in neurons does not induce their proliferation, but leads to neuronal cell death and consequent development of a neurodegenerative phenotype. Interestingly, while cancer and neurodegenerative diseases such as Alzheimer's disease are placed at the opposite sides of cell division spectrum, both start with cell cycle dysregulation and stimulation of proliferation. It seems that MYC action directed toward neuron cell proliferation and neural tissue repair collides with evolutional loss of regenerative capacity of CNS neurons in order to strengthen synaptic structure, to protect our cognitive abilities and therefore character. Accordingly, there are abundant mechanisms that block its expression and action specifically in the brain. Moreover, while MYC expression in brain neurons during neurodegenerative processes is related to their death, there are obvious evidences that MYC action after physical injury is beneficial in case of peripheral nerve recovery. MYC might be a useful tool to repair brain cells upon development of neurodegenerative disease or CNS trauma, including stroke and traumatic brain and spinal cord injury, as even imperfect axonal growth and regeneration strategies will likely be of profound benefit. Understanding complex control of MYC action in the brain might have important therapeutic significance, but also it may contribute to the comprehension of development of neurodegenerative diseases.
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Affiliation(s)
| | - Dragan Marinkovic
- Faculty of Special Education and Rehabilitation, University of Belgrade, Visokog Stevana 2, 11000, Belgrade, Serbia.
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21
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Pellanda P, Dalsass M, Filipuzzi M, Loffreda A, Verrecchia A, Castillo Cano V, Thabussot H, Doni M, Morelli MJ, Soucek L, Kress T, Mazza D, Mapelli M, Beaulieu ME, Amati B, Sabò A. Integrated requirement of non-specific and sequence-specific DNA binding in Myc-driven transcription. EMBO J 2021; 40:e105464. [PMID: 33792944 DOI: 10.15252/embj.2020105464] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 02/15/2021] [Accepted: 02/24/2021] [Indexed: 12/17/2022] Open
Abstract
Eukaryotic transcription factors recognize specific DNA sequence motifs, but are also endowed with generic, non-specific DNA-binding activity. How these binding modes are integrated to determine select transcriptional outputs remains unresolved. We addressed this question by site-directed mutagenesis of the Myc transcription factor. Impairment of non-specific DNA backbone contacts caused pervasive loss of genome interactions and gene regulation, associated with increased intra-nuclear mobility of the Myc protein in murine cells. In contrast, a mutant lacking base-specific contacts retained DNA-binding and mobility profiles comparable to those of the wild-type protein, but failed to recognize its consensus binding motif (E-box) and could not activate Myc-target genes. Incidentally, this mutant gained weak affinity for an alternative motif, driving aberrant activation of different genes. Altogether, our data show that non-specific DNA binding is required to engage onto genomic regulatory regions; sequence recognition in turn contributes to transcriptional activation, acting at distinct levels: stabilization and positioning of Myc onto DNA, and-unexpectedly-promotion of its transcriptional activity. Hence, seemingly pervasive genome interaction profiles, as detected by ChIP-seq, actually encompass diverse DNA-binding modalities, driving defined, sequence-dependent transcriptional responses.
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Affiliation(s)
- Paola Pellanda
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy.,Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia (IIT), Milan, Italy
| | - Mattia Dalsass
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy
| | | | - Alessia Loffreda
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | | | - Virginia Castillo Cano
- Peptomyc S.L., Barcelona, Spain.,Vall d'Hebron Institute of Oncology (VHIO), Edifici Cellex, Barcelona, Spain
| | | | - Mirko Doni
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy
| | - Marco J Morelli
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia (IIT), Milan, Italy
| | - Laura Soucek
- Peptomyc S.L., Barcelona, Spain.,Vall d'Hebron Institute of Oncology (VHIO), Edifici Cellex, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.,Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Theresia Kress
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia (IIT), Milan, Italy
| | - Davide Mazza
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Marina Mapelli
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy
| | | | - Bruno Amati
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy
| | - Arianna Sabò
- European Institute of Oncology (IEO) - IRCCS, Milan, Italy
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22
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Fairlie WD, Lee EF. Co-Operativity between MYC and BCL-2 Pro-Survival Proteins in Cancer. Int J Mol Sci 2021; 22:ijms22062841. [PMID: 33799592 PMCID: PMC8000576 DOI: 10.3390/ijms22062841] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 12/30/2022] Open
Abstract
B-Cell Lymphoma 2 (BCL-2), c-MYC and related proteins are arguably amongst the most widely studied in all of biology. Every year there are thousands of papers reporting on different aspects of their biochemistry, cellular and physiological mechanisms and functions. This plethora of literature can be attributed to both proteins playing essential roles in the normal functioning of a cell, and by extension a whole organism, but also due to their central role in disease, most notably, cancer. Many cancers arise due to genetic lesions resulting in deregulation of both proteins, and indeed the development and survival of tumours is often dependent on co-operativity between these protein families. In this review we will discuss the individual roles of both proteins in cancer, describe cancers where co-operativity between them has been well-characterised and finally, some strategies to target these proteins therapeutically.
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Affiliation(s)
- Walter Douglas Fairlie
- Olivia Newton-John Cancer Research Institute, Heidelberg, VIC 3084, Australia;
- School of Cancer Medicine, La Trobe University, Melbourne, VIC 3084, Australia
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3084, Australia
| | - Erinna F. Lee
- Olivia Newton-John Cancer Research Institute, Heidelberg, VIC 3084, Australia;
- School of Cancer Medicine, La Trobe University, Melbourne, VIC 3084, Australia
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3084, Australia
- Correspondence:
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23
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Liu R, Shi P, Wang Z, Yuan C, Cui H. Molecular Mechanisms of MYCN Dysregulation in Cancers. Front Oncol 2021; 10:625332. [PMID: 33614505 PMCID: PMC7886978 DOI: 10.3389/fonc.2020.625332] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 12/18/2020] [Indexed: 12/17/2022] Open
Abstract
MYCN, a member of MYC proto-oncogene family, encodes a basic helix-loop-helix transcription factor N-MYC. Abnormal expression of N-MYC is correlated with high-risk cancers and poor prognosis. Initially identified as an amplified oncogene in neuroblastoma in 1983, the oncogenic effect of N-MYC is expanded to multiple neuronal and nonneuronal tumors. Direct targeting N-MYC remains challenge due to its "undruggable" features. Therefore, alternative therapeutic approaches for targeting MYCN-driven tumors have been focused on the disruption of transcription, translation, protein stability as well as synthetic lethality of MYCN. In this review, we summarize the latest advances in understanding the molecular mechanisms of MYCN dysregulation in cancers.
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Affiliation(s)
- Ruochen Liu
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
- Cancer Center, Reproductive Medicine Center, Medical Research Institute, Southwest University, Chongqing, China
- NHC Key Laboratory of Birth Defects and Reproductive Health (Chongqing Key Laboratory of Birth Defects and Reproductive Health, Chongqing Population and Family Planning Science and Technology Research Institute), Chongqing, China
| | - Pengfei Shi
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
- Cancer Center, Reproductive Medicine Center, Medical Research Institute, Southwest University, Chongqing, China
- NHC Key Laboratory of Birth Defects and Reproductive Health (Chongqing Key Laboratory of Birth Defects and Reproductive Health, Chongqing Population and Family Planning Science and Technology Research Institute), Chongqing, China
| | - Zhongze Wang
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
- Cancer Center, Reproductive Medicine Center, Medical Research Institute, Southwest University, Chongqing, China
| | - Chaoyu Yuan
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
- Cancer Center, Reproductive Medicine Center, Medical Research Institute, Southwest University, Chongqing, China
| | - Hongjuan Cui
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
- Cancer Center, Reproductive Medicine Center, Medical Research Institute, Southwest University, Chongqing, China
- NHC Key Laboratory of Birth Defects and Reproductive Health (Chongqing Key Laboratory of Birth Defects and Reproductive Health, Chongqing Population and Family Planning Science and Technology Research Institute), Chongqing, China
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24
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Ubiquitylation of MYC couples transcription elongation with double-strand break repair at active promoters. Mol Cell 2021; 81:830-844.e13. [PMID: 33453168 DOI: 10.1016/j.molcel.2020.12.035] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 10/14/2020] [Accepted: 12/16/2020] [Indexed: 12/13/2022]
Abstract
The MYC oncoprotein globally affects the function of RNA polymerase II (RNAPII). The ability of MYC to promote transcription elongation depends on its ubiquitylation. Here, we show that MYC and PAF1c (polymerase II-associated factor 1 complex) interact directly and mutually enhance each other's association with active promoters. PAF1c is rapidly transferred from MYC onto RNAPII. This transfer is driven by the HUWE1 ubiquitin ligase and is required for MYC-dependent transcription elongation. MYC and HUWE1 promote histone H2B ubiquitylation, which alters chromatin structure both for transcription elongation and double-strand break repair. Consistently, MYC suppresses double-strand break accumulation in active genes in a strictly PAF1c-dependent manner. Depletion of PAF1c causes transcription-dependent accumulation of double-strand breaks, despite widespread repair-associated DNA synthesis. Our data show that the transfer of PAF1c from MYC onto RNAPII efficiently couples transcription elongation with double-strand break repair to maintain the genomic integrity of MYC-driven tumor cells.
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25
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Rosselot C, Baumel-Alterzon S, Li Y, Brill G, Lambertini L, Katz LS, Lu G, Garcia-Ocaña A, Scott DK. The many lives of Myc in the pancreatic β-cell. J Biol Chem 2021; 296:100122. [PMID: 33239359 PMCID: PMC7949031 DOI: 10.1074/jbc.rev120.011149] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 11/20/2020] [Accepted: 11/25/2020] [Indexed: 12/19/2022] Open
Abstract
Diabetes results from insufficient numbers of functional pancreatic β-cells. Thus, increasing the number of available functional β-cells ex vivo for transplantation, or regenerating them in situ in diabetic patients, is a major focus of diabetes research. The transcription factor, Myc, discovered decades ago lies at the nexus of most, if not all, known proliferative pathways. Based on this, many studies in the 1990s and early 2000s explored the potential of harnessing Myc expression to expand β-cells for diabetes treatment. Nearly all these studies in β-cells used pathophysiological or supraphysiological levels of Myc and reported enhanced β-cell death, dedifferentiation, or the formation of insulinomas if cooverexpressed with Bcl-xL, an inhibitor of apoptosis. This obviously reduced the enthusiasm for Myc as a therapeutic target for β-cell regeneration. However, recent studies indicate that "gentle" induction of Myc expression enhances β-cell replication without induction of cell death or loss of insulin secretion, suggesting that appropriate levels of Myc could have therapeutic potential for β-cell regeneration. Furthermore, although it has been known for decades that Myc is induced by glucose in β-cells, very little is known about how this essential anabolic transcription factor perceives and responds to nutrients and increased insulin demand in vivo. Here we summarize the previous and recent knowledge of Myc in the β-cell, its potential for β-cell regeneration, and its physiological importance for neonatal and adaptive β-cell expansion.
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Affiliation(s)
- Carolina Rosselot
- Diabetes Obesity Metabolism Institute, and the Mindich Child Health and Development Institute, The Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Sharon Baumel-Alterzon
- Diabetes Obesity Metabolism Institute, and the Mindich Child Health and Development Institute, The Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Yansui Li
- Diabetes Obesity Metabolism Institute, and the Mindich Child Health and Development Institute, The Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Gabriel Brill
- Diabetes Obesity Metabolism Institute, and the Mindich Child Health and Development Institute, The Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Luca Lambertini
- Diabetes Obesity Metabolism Institute, and the Mindich Child Health and Development Institute, The Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Liora S Katz
- Diabetes Obesity Metabolism Institute, and the Mindich Child Health and Development Institute, The Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Geming Lu
- Diabetes Obesity Metabolism Institute, and the Mindich Child Health and Development Institute, The Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Adolfo Garcia-Ocaña
- Diabetes Obesity Metabolism Institute, and the Mindich Child Health and Development Institute, The Icahn School of Medicine at Mount Sinai, New York, New York, USA.
| | - Donald K Scott
- Diabetes Obesity Metabolism Institute, and the Mindich Child Health and Development Institute, The Icahn School of Medicine at Mount Sinai, New York, New York, USA
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26
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Horisawa K, Udono M, Ueno K, Ohkawa Y, Nagasaki M, Sekiya S, Suzuki A. The Dynamics of Transcriptional Activation by Hepatic Reprogramming Factors. Mol Cell 2020; 79:660-676.e8. [PMID: 32755593 DOI: 10.1016/j.molcel.2020.07.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/18/2020] [Accepted: 07/09/2020] [Indexed: 02/07/2023]
Abstract
Specific combinations of two transcription factors (Hnf4α plus Foxa1, Foxa2, or Foxa3) can induce direct conversion of mouse fibroblasts into hepatocyte-like cells. However, the molecular mechanisms underlying hepatic reprogramming are largely unknown. Here, we show that the Foxa protein family members and Hnf4α sequentially and cooperatively bind to chromatin to activate liver-specific gene expression. Although all Foxa proteins bind to and open regions of closed chromatin as pioneer factors, Foxa3 has the unique potential of transferring from the distal to proximal regions of the transcription start site of target genes, binding RNA polymerase II, and co-traversing target genes. These distinctive characteristics of Foxa3 are essential for inducing the hepatic fate in fibroblasts. Similar functional coupling of transcription factors to RNA polymerase II may occur in other contexts whereby transcriptional activation can induce cell differentiation.
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Affiliation(s)
- Kenichi Horisawa
- Division of Organogenesis and Regeneration, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Miyako Udono
- Division of Organogenesis and Regeneration, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Kazuko Ueno
- Genome Medical Science Project, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
| | - Yasuyuki Ohkawa
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Masao Nagasaki
- Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; Human Biosciences Unit for the Top Global Course, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto 606-8507, Japan
| | - Sayaka Sekiya
- Division of Organogenesis and Regeneration, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Atsushi Suzuki
- Division of Organogenesis and Regeneration, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan.
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Nie Z, Guo C, Das SK, Chow CC, Batchelor E, Simons SS, Levens D. Dissecting transcriptional amplification by MYC. eLife 2020; 9:52483. [PMID: 32715994 PMCID: PMC7384857 DOI: 10.7554/elife.52483] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 07/08/2020] [Indexed: 12/13/2022] Open
Abstract
Supraphysiological MYC levels are oncogenic. Originally considered a typical transcription factor recruited to E-boxes (CACGTG), another theory posits MYC a global amplifier increasing output at all active promoters. Both models rest on large-scale genome-wide "-omics'. Because the assumptions, statistical parameter and model choice dictates the '-omic' results, whether MYC is a general or specific transcription factor remains controversial. Therefore, an orthogonal series of experiments interrogated MYC's effect on the expression of synthetic reporters. Dose-dependently, MYC increased output at minimal promoters with or without an E-box. Driving minimal promoters with exogenous (glucocorticoid receptor) or synthetic transcription factors made expression more MYC-responsive, effectively increasing MYC-amplifier gain. Mutations of conserved MYC-Box regions I and II impaired amplification, whereas MYC-box III mutations delivered higher reporter output indicating that MBIII limits over-amplification. Kinetic theory and experiments indicate that MYC activates at least two steps in the transcription-cycle to explain the non-linear amplification of transcription that is essential for global, supraphysiological transcription in cancer.
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Affiliation(s)
- Zuqin Nie
- Laboratory of Pathology, CCR, NCI, NIH, Bethesda, United States
| | - Chunhua Guo
- Steroid Hormones Section, NIDDK/LERB, NIH, Bethesda, United States
| | - Subhendu K Das
- Laboratory of Pathology, CCR, NCI, NIH, Bethesda, United States
| | - Carson C Chow
- Mathematical Biology Section, NIDDK/LBM, NIH, Bethesda, United States
| | - Eric Batchelor
- Laboratory of Pathology, CCR, NCI, NIH, Bethesda, United States.,Laboratory of Cell Biology, CCR, NCI, NIH, Bethesda, United States.,Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, United States
| | - S Stoney Simons
- Steroid Hormones Section, NIDDK/LERB, NIH, Bethesda, United States
| | - David Levens
- Laboratory of Pathology, CCR, NCI, NIH, Bethesda, United States
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Srivastava D, Mahony S. Sequence and chromatin determinants of transcription factor binding and the establishment of cell type-specific binding patterns. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2020; 1863:194443. [PMID: 31639474 PMCID: PMC7166147 DOI: 10.1016/j.bbagrm.2019.194443] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/21/2019] [Accepted: 10/06/2019] [Indexed: 12/14/2022]
Abstract
Transcription factors (TFs) selectively bind distinct sets of sites in different cell types. Such cell type-specific binding specificity is expected to result from interplay between the TF's intrinsic sequence preferences, cooperative interactions with other regulatory proteins, and cell type-specific chromatin landscapes. Cell type-specific TF binding events are highly correlated with patterns of chromatin accessibility and active histone modifications in the same cell type. However, since concurrent chromatin may itself be a consequence of TF binding, chromatin landscapes measured prior to TF activation provide more useful insights into how cell type-specific TF binding events became established in the first place. Here, we review the various sequence and chromatin determinants of cell type-specific TF binding specificity. We identify the current challenges and opportunities associated with computational approaches to characterizing, imputing, and predicting cell type-specific TF binding patterns. We further focus on studies that characterize TF binding in dynamic regulatory settings, and we discuss how these studies are leading to a more complex and nuanced understanding of dynamic protein-DNA binding activities. We propose that TF binding activities at individual sites can be viewed along a two-dimensional continuum of local sequence and chromatin context. Under this view, cell type-specific TF binding activities may result from either strongly favorable sequence features or strongly favorable chromatin context.
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Affiliation(s)
- Divyanshi Srivastava
- Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Shaun Mahony
- Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America.
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29
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Beaulieu ME, Castillo F, Soucek L. Structural and Biophysical Insights into the Function of the Intrinsically Disordered Myc Oncoprotein. Cells 2020; 9:E1038. [PMID: 32331235 PMCID: PMC7226237 DOI: 10.3390/cells9041038] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 12/13/2022] Open
Abstract
Myc is a transcription factor driving growth and proliferation of cells and involved in the majority of human tumors. Despite a huge body of literature on this critical oncogene, our understanding of the exact molecular determinants and mechanisms that underlie its function is still surprisingly limited. Indubitably though, its crucial and non-redundant role in cancer biology makes it an attractive target. However, achieving successful clinical Myc inhibition has proven challenging so far, as this nuclear protein is an intrinsically disordered polypeptide devoid of any classical ligand binding pockets. Indeed, Myc only adopts a (partially) folded structure in some contexts and upon interacting with some protein partners, for instance when dimerizing with MAX to bind DNA. Here, we review the cumulative knowledge on Myc structure and biophysics and discuss the implications for its biological function and the development of improved Myc inhibitors. We focus this biophysical walkthrough mainly on the basic region helix-loop-helix leucine zipper motif (bHLHLZ), as it has been the principal target for inhibitory approaches so far.
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Affiliation(s)
| | | | - Laura Soucek
- Peptomyc S.L., Edifici Cellex, 08035 Barcelona, Spain; (F.C.); (L.S.)
- Vall d’Hebron Institute of Oncology (VHIO), Edifici Cellex, 08035 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08035 Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, 08035 Bellaterra, Spain
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30
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Liu M, Yao B, Gui T, Guo C, Wu X, Li J, Ma L, Deng Y, Xu P, Wang Y, Yang D, Li Q, Zeng X, Li X, Hu R, Ge J, Yu Z, Chen Y, Chen B, Ju J, Zhao Q. PRMT5-dependent transcriptional repression of c-Myc target genes promotes gastric cancer progression. Theranostics 2020; 10:4437-4452. [PMID: 32292506 PMCID: PMC7150477 DOI: 10.7150/thno.42047] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 02/25/2020] [Indexed: 12/17/2022] Open
Abstract
The proto-oncogene c-Myc regulates multiple biological processes mainly through selectively activating gene expression. However, the mechanisms underlying c-Myc-mediated gene repression in the context of cancer remain less clear. This study aimed to clarify the role of PRMT5 in the transcriptional repression of c-Myc target genes in gastric cancer. Methods: Immunohistochemistry was used to evaluate the expression of PRMT5, c-Myc and target genes in gastric cancer patients. PRMT5 and c-Myc interaction was assessed by immunofluorescence, co-immunoprecipitation and GST pull-down assays. Bioinformatics analysis, immunoblotting, real-time PCR, chromatin immunoprecipitation, and rescue experiments were used to evaluate the mechanism. Results: We found that c-Myc directly interacts with protein arginine methyltransferase 5 (PRMT5) to transcriptionally repress the expression of a cohort of genes, including PTEN, CDKN2C (p18INK4C), CDKN1A (p21CIP1/WAF1), CDKN1C (p57KIP2) and p63, to promote gastric cancer cell growth. Specifically, we found that PRMT5 was required to promote gastric cancer cell growth in vitro and in vivo, and for transcriptional repression of this cohort of genes, which was dependent on its methyltransferase activity. Consistently, the promoters of this gene cohort were enriched for both PRMT5-mediated symmetric di-methylation of histone H4 on Arg 3 (H4R3me2s) and c-Myc, and c-Myc depletion also upregulated their expression. H4R3me2s also colocalized with the c-Myc-binding E-box motif (CANNTG) on these genes. We show that PRMT5 directly binds to c-Myc, and this binding is required for transcriptional repression of the target genes. Both c-Myc and PRMT5 expression levels were upregulated in primary human gastric cancer tissues, and their expression levels inversely correlated with clinical outcomes. Conclusions: Taken together, our study reveals a novel mechanism by which PRMT5-dependent transcriptional repression of c-Myc target genes is required for gastric cancer progression, and provides a potential new strategy for therapeutic targeting of gastric cancer.
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31
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Abstract
Targeting the function of MYC oncoproteins holds the promise of achieving conceptually new and effective anticancer therapies that can be applied to a broad range of tumors. The nature of the target however—a broadly, possibly universally acting transcription factor that has no enzymatic activity and is largely unstructured unless complexed with partner proteins—has so far defied the development of clinically applicable MYC-directed therapies. At the same time, lingering questions about exactly which functions of MYC proteins account for their pervasive oncogenic role in human tumors and need to be targeted have prevented the development of effective therapies using surrogate targets that act in critical MYC-dependent pathways. In this review, we therefore argue that rigorous testing of critical oncogenic functions and protein/protein interactions and new chemical approaches to target them are necessary to successfully eradicate MYC-driven tumors.
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Affiliation(s)
- Elmar Wolf
- Department of Biochemistry and Molecular Biology, Theodor Boveri Institute, University of Würzburg, 97074 Würzburg, Germany;,
| | - Martin Eilers
- Department of Biochemistry and Molecular Biology, Theodor Boveri Institute, University of Würzburg, 97074 Würzburg, Germany;,
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32
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Baluapuri A, Wolf E, Eilers M. Target gene-independent functions of MYC oncoproteins. Nat Rev Mol Cell Biol 2020; 21:255-267. [PMID: 32071436 DOI: 10.1038/s41580-020-0215-2] [Citation(s) in RCA: 167] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2020] [Indexed: 12/13/2022]
Abstract
Oncoproteins of the MYC family are major drivers of human tumorigenesis. Since a large body of evidence indicates that MYC proteins are transcription factors, studying their function has focused on the biology of their target genes. Detailed studies of MYC-dependent changes in RNA levels have provided contrasting models of the oncogenic activity of MYC proteins through either enhancing or repressing the expression of specific target genes, or as global amplifiers of transcription. In this Review, we first summarize the biochemistry of MYC proteins and what is known (or is unclear) about the MYC target genes. We then discuss recent progress in defining the interactomes of MYC and MYCN and how this information affects central concepts of MYC biology, focusing on mechanisms by which MYC proteins modulate transcription. MYC proteins promote transcription termination upon stalling of RNA polymerase II, and we propose that this mechanism enhances the stress resilience of basal transcription. Furthermore, MYC proteins coordinate transcription elongation with DNA replication and cell cycle progression. Finally, we argue that the mechanism by which MYC proteins regulate the transcription machinery is likely to promote tumorigenesis independently of global or relative changes in the expression of their target genes.
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Affiliation(s)
- Apoorva Baluapuri
- Theodor Boveri Institute, Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Elmar Wolf
- Theodor Boveri Institute, Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Martin Eilers
- Theodor Boveri Institute, Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany.
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33
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ZFP281 Recruits MYC to Active Promoters in Regulating Transcriptional Initiation and Elongation. Mol Cell Biol 2019; 39:MCB.00329-19. [PMID: 31570506 DOI: 10.1128/mcb.00329-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 09/24/2019] [Indexed: 02/02/2023] Open
Abstract
The roles of the MYC transcription factor in transcriptional regulation have been studied intensively. However, the general mechanism underlying the recruitment of MYC to chromatin is less clear. Here, we found that the Krüppel-like transcription factor ZFP281 plays important roles in recruiting MYC to active promoters in mouse embryonic stem cells. At the genome scale, ZFP281 is broadly associated with MYC, and the depletion of ZFP281 significantly reduces the levels of MYC and RNA polymerase II at the ZFP281- and MYC-cobound genes. Specially, we found that recruitment is required for the regulation of the Lin28a oncogene and pri-let-7 transcription. Our results therefore suggest a major role of ZFP281 in recruiting MYC to chromatin and the integration of ZFP281 and the MYC/LIN28A/Let-7 loop into a multilevel circuit.
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34
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Tesi A, de Pretis S, Furlan M, Filipuzzi M, Morelli MJ, Andronache A, Doni M, Verrecchia A, Pelizzola M, Amati B, Sabò A. An early Myc-dependent transcriptional program orchestrates cell growth during B-cell activation. EMBO Rep 2019; 20:e47987. [PMID: 31334602 PMCID: PMC6726900 DOI: 10.15252/embr.201947987] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 06/18/2019] [Accepted: 06/27/2019] [Indexed: 12/18/2022] Open
Abstract
Upon activation, lymphocytes exit quiescence and undergo substantial increases in cell size, accompanied by activation of energy-producing and anabolic pathways, widespread chromatin decompaction, and elevated transcriptional activity. These changes depend upon prior induction of the Myc transcription factor, but how Myc controls them remains unclear. We addressed this issue by profiling the response to LPS stimulation in wild-type and c-myc-deleted primary mouse B-cells. Myc is rapidly induced, becomes detectable on virtually all active promoters and enhancers, but has no direct impact on global transcriptional activity. Instead, Myc contributes to the swift up- and down-regulation of several hundred genes, including many known regulators of the aforementioned cellular processes. Myc-activated promoters are enriched for E-box consensus motifs, bind Myc at the highest levels, and show enhanced RNA Polymerase II recruitment, the opposite being true at down-regulated loci. Remarkably, the Myc-dependent signature identified in activated B-cells is also enriched in Myc-driven B-cell lymphomas: hence, besides modulation of new cancer-specific programs, the oncogenic action of Myc may largely rely on sustained deregulation of its normal physiological targets.
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Affiliation(s)
- Alessandra Tesi
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
| | - Stefano de Pretis
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
| | - Mattia Furlan
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
| | - Marco Filipuzzi
- Department of Experimental OncologyEuropean Institute of Oncology (IEO)‐IRCCSMilanItaly
| | - Marco J Morelli
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
- Present address:
Center for Translational Genomics and BioinformaticsIRCCS San Raffaele Scientific InstituteMilanItaly
| | - Adrian Andronache
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
- Present address:
Experimental Therapeutics Program of IFOM ‐ The FIRC Institute of Molecular OncologyMilanItaly
| | - Mirko Doni
- Department of Experimental OncologyEuropean Institute of Oncology (IEO)‐IRCCSMilanItaly
| | - Alessandro Verrecchia
- Department of Experimental OncologyEuropean Institute of Oncology (IEO)‐IRCCSMilanItaly
| | - Mattia Pelizzola
- Center for Genomic Science of IIT@SEMMFondazione Istituto Italiano di Tecnologia (IIT)MilanItaly
| | - Bruno Amati
- Department of Experimental OncologyEuropean Institute of Oncology (IEO)‐IRCCSMilanItaly
| | - Arianna Sabò
- Department of Experimental OncologyEuropean Institute of Oncology (IEO)‐IRCCSMilanItaly
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35
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Berger A, Brady NJ, Bareja R, Robinson B, Conteduca V, Augello MA, Puca L, Ahmed A, Dardenne E, Lu X, Hwang I, Bagadion AM, Sboner A, Elemento O, Paik J, Yu J, Barbieri CE, Dephoure N, Beltran H, Rickman DS. N-Myc-mediated epigenetic reprogramming drives lineage plasticity in advanced prostate cancer. J Clin Invest 2019; 129:3924-3940. [PMID: 31260412 DOI: 10.1172/jci127961] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Despite recent therapeutic advances, prostate cancer remains a leading cause of cancer-related death. A subset of castration resistant prostate cancers become androgen receptor (AR) signaling-independent and develop neuroendocrine prostate cancer (NEPC) features through lineage plasticity. These NEPC tumors, associated with aggressive disease and poor prognosis, are driven, in part, by aberrant expression of N-Myc, through mechanisms that remain unclear. Integrative analysis of the N-Myc transcriptome, cistrome and interactome using in vivo, in vitro and ex vivo models (including patient-derived organoids) identified a lineage switch towards a neural identity associated with epigenetic reprogramming. N-Myc and known AR-co-factors (e.g., FOXA1 and HOXB13) overlapped, independently of AR, at genomic loci implicated in neural lineage specification. Moreover, histone marks specifically associated with lineage-defining genes were reprogrammed by N-Myc. We also demonstrated that the N-Myc-induced molecular program accurately classifies our cohort of patients with advanced prostate cancer. Finally, we revealed the potential for EZH2 inhibition to reverse the N-Myc-induced suppression of epithelial lineage genes. Altogether, our data provide insights on how N-Myc regulates lineage plasticity and epigenetic reprogramming associated with lineage-specification. The N-Myc signature we defined could also help predict the evolution of prostate cancer and thus better guide the choice of future therapeutic strategies.
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Affiliation(s)
| | | | - Rohan Bareja
- Caryl and Israel Englander Institute for Precision Medicine, NewYork-Presbyterian Hospital
| | - Brian Robinson
- Department of Pathology and Laboratory Medicine.,Caryl and Israel Englander Institute for Precision Medicine, NewYork-Presbyterian Hospital
| | | | | | | | - Adnan Ahmed
- Department of Biochemistry, Weill Cornell Medicine, New York, New York, USA
| | | | - Xiaodong Lu
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Inah Hwang
- Department of Pathology and Laboratory Medicine
| | | | - Andrea Sboner
- Department of Pathology and Laboratory Medicine.,Caryl and Israel Englander Institute for Precision Medicine, NewYork-Presbyterian Hospital.,Department of Physiology and Biophysics, Institute for Computational Biomedicine, and.,Meyer Cancer Center, Weill Cornell Medicine, New York, New York, USA
| | - Olivier Elemento
- Caryl and Israel Englander Institute for Precision Medicine, NewYork-Presbyterian Hospital.,Department of Physiology and Biophysics, Institute for Computational Biomedicine, and.,Meyer Cancer Center, Weill Cornell Medicine, New York, New York, USA
| | - Jihye Paik
- Department of Pathology and Laboratory Medicine.,Meyer Cancer Center, Weill Cornell Medicine, New York, New York, USA
| | - Jindan Yu
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Christopher E Barbieri
- Caryl and Israel Englander Institute for Precision Medicine, NewYork-Presbyterian Hospital.,Department of Urology, and.,Meyer Cancer Center, Weill Cornell Medicine, New York, New York, USA
| | - Noah Dephoure
- Department of Biochemistry, Weill Cornell Medicine, New York, New York, USA.,Meyer Cancer Center, Weill Cornell Medicine, New York, New York, USA
| | - Himisha Beltran
- Caryl and Israel Englander Institute for Precision Medicine, NewYork-Presbyterian Hospital.,Department of Medicine.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - David S Rickman
- Department of Pathology and Laboratory Medicine.,Caryl and Israel Englander Institute for Precision Medicine, NewYork-Presbyterian Hospital.,Meyer Cancer Center, Weill Cornell Medicine, New York, New York, USA
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36
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Wollman AJM, Hedlund EG, Shashkova S, Leake MC. Towards mapping the 3D genome through high speed single-molecule tracking of functional transcription factors in single living cells. Methods 2019; 170:82-89. [PMID: 31252059 PMCID: PMC6971689 DOI: 10.1016/j.ymeth.2019.06.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/22/2019] [Indexed: 10/26/2022] Open
Abstract
How genomic DNA is organized in the nucleus is a long-standing question. We describe a single-molecule bioimaging method utilizing super-localization precision coupled to fully quantitative image analysis tools, towards determining snapshots of parts of the 3D genome architecture of model eukaryote budding yeast Saccharomyces cerevisiae with exceptional millisecond time resolution. We employ astigmatism imaging to enable robust extraction of 3D position data on genomically encoded fluorescent protein reporters that bind to DNA. Our relatively straightforward method enables snippets of 3D architectures of likely single genome conformations to be resolved captured via DNA-sequence specific binding proteins in single functional living cells.
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Affiliation(s)
- Adam J M Wollman
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Erik G Hedlund
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Sviatlana Shashkova
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Mark C Leake
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
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37
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Samee MAH, Bruneau BG, Pollard KS. A De Novo Shape Motif Discovery Algorithm Reveals Preferences of Transcription Factors for DNA Shape Beyond Sequence Motifs. Cell Syst 2019; 8:27-42.e6. [PMID: 30660610 PMCID: PMC6368855 DOI: 10.1016/j.cels.2018.12.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 08/18/2018] [Accepted: 12/03/2018] [Indexed: 12/17/2022]
Abstract
DNA shape adds specificity to sequence motifs but has not been explored systematically outside this context. We hypothesized that DNA-binding proteins (DBPs) preferentially occupy DNA with specific structures ("shape motifs") regardless of whether or not these correspond to high information content sequence motifs. We present ShapeMF, a Gibbs sampling algorithm that identifies de novo shape motifs. Using binding data from hundreds of in vivo and in vitro experiments, we show that most DBPs have shape motifs and can occupy these in the absence of sequence motifs. This "shape-only binding" is common for many DBPs and in regions co-bound by multiple DBPs. When shape and sequence motifs co-occur, they can be overlapping, flanking, or separated by consistent spacing. Finally, DBPs within the same protein family have different shape motifs, explaining their distinct genome-wide occupancy despite having similar sequence motifs. These results suggest that shape motifs not only complement sequence motifs but also facilitate recognition of DNA beyond conventionally defined sequence motifs.
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Affiliation(s)
| | - Benoit G Bruneau
- Gladstone Institutes, San Francisco, CA 94158, USA; Department of Pediatrics and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Katherine S Pollard
- Gladstone Institutes, San Francisco, CA 94158, USA; Department of Epidemiology & Biostatistics, Institute for Human Genetics, Quantitative Biology Institute, and Institute for Computational Health Sciences, University of California, San Francisco, San Francisco, CA 94158, USA; Chan-Zuckerberg Biohub, San Francisco, CA 94158, USA.
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38
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Keilwagen J, Posch S, Grau J. Accurate prediction of cell type-specific transcription factor binding. Genome Biol 2019; 20:9. [PMID: 30630522 PMCID: PMC6327544 DOI: 10.1186/s13059-018-1614-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 12/18/2018] [Indexed: 01/11/2023] Open
Abstract
Prediction of cell type-specific, in vivo transcription factor binding sites is one of the central challenges in regulatory genomics. Here, we present our approach that earned a shared first rank in the "ENCODE-DREAM in vivo Transcription Factor Binding Site Prediction Challenge" in 2017. In post-challenge analyses, we benchmark the influence of different feature sets and find that chromatin accessibility and binding motifs are sufficient to yield state-of-the-art performance. Finally, we provide 682 lists of predicted peaks for a total of 31 transcription factors in 22 primary cell types and tissues and a user-friendly version of our approach, Catchitt, for download.
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Affiliation(s)
- Jens Keilwagen
- Institute for Biosafety in Plant Biotechnology, Julius Kühn-Institut (JKI) - Federal Research Centre for Cultivated Plants, Erwin-Baur-Straße 27, Quedlinburg, 06484 Germany
| | - Stefan Posch
- Institute of Computer Science, Martin Luther University Halle–Wittenberg, Von-Seckendorff-Platz 1, Halle (Saale), 06120 Germany
| | - Jan Grau
- Institute of Computer Science, Martin Luther University Halle–Wittenberg, Von-Seckendorff-Platz 1, Halle (Saale), 06120 Germany
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Kalkat M, Resetca D, Lourenco C, Chan PK, Wei Y, Shiah YJ, Vitkin N, Tong Y, Sunnerhagen M, Done SJ, Boutros PC, Raught B, Penn LZ. MYC Protein Interactome Profiling Reveals Functionally Distinct Regions that Cooperate to Drive Tumorigenesis. Mol Cell 2018; 72:836-848.e7. [PMID: 30415952 DOI: 10.1016/j.molcel.2018.09.031] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 08/09/2018] [Accepted: 09/21/2018] [Indexed: 12/14/2022]
Abstract
Transforming members of the MYC family (MYC, MYCL1, and MYCN) encode transcription factors containing six highly conserved regions, termed MYC homology boxes (MBs). By conducting proteomic profiling of the MB interactomes, we demonstrate that half of the MYC interactors require one or more MBs for binding. Comprehensive phenotypic analyses reveal that two MBs, MB0 and MBII, are universally required for transformation. MBII mediates interactions with acetyltransferase-containing complexes, enabling histone acetylation, and is essential for MYC-dependent tumor initiation. By contrast, MB0 mediates interactions with transcription elongation factors via direct binding to the general transcription factor TFIIF. MB0 is dispensable for tumor initiation but is a major accelerator of tumor growth. Notably, the full transforming activity of MYC can be restored by co-expression of the non-transforming MB0 and MBII deletion proteins, indicating that these two regions confer separate molecular functions, both of which are required for oncogenic MYC activity.
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Affiliation(s)
- Manpreet Kalkat
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Diana Resetca
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Corey Lourenco
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Pak-Kei Chan
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Yong Wei
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Structural Genomics Consortium, Toronto, ON M5G 1L7, Canada
| | - Yu-Jia Shiah
- Ontario Institute for Cancer Research, Toronto, ON M5G 0A3, Canada
| | - Natasha Vitkin
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Yufeng Tong
- Structural Genomics Consortium, Toronto, ON M5G 1L7, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5A 1A8, Canada
| | - Maria Sunnerhagen
- Department of Physics, Chemistry and Biology, Linköping University, 581 83 Linköping, Sweden
| | - Susan J Done
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Paul C Boutros
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Ontario Institute for Cancer Research, Toronto, ON M5G 0A3, Canada
| | - Brian Raught
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada.
| | - Linda Z Penn
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada.
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40
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Tu WB, Shiah YJ, Lourenco C, Mullen PJ, Dingar D, Redel C, Tamachi A, Ba-Alawi W, Aman A, Al-Awar R, Cescon DW, Haibe-Kains B, Arrowsmith CH, Raught B, Boutros PC, Penn LZ. MYC Interacts with the G9a Histone Methyltransferase to Drive Transcriptional Repression and Tumorigenesis. Cancer Cell 2018; 34:579-595.e8. [PMID: 30300580 DOI: 10.1016/j.ccell.2018.09.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 06/30/2018] [Accepted: 09/04/2018] [Indexed: 12/22/2022]
Abstract
MYC is an oncogenic driver that regulates transcriptional activation and repression. Surprisingly, mechanisms by which MYC promotes malignant transformation remain unclear. We demonstrate that MYC interacts with the G9a H3K9-methyltransferase complex to control transcriptional repression. Inhibiting G9a hinders MYC chromatin binding at MYC-repressed genes and de-represses gene expression. By identifying the MYC box II region as essential for MYC-G9a interaction, a long-standing missing link between MYC transformation and gene repression is unveiled. Across breast cancer cell lines, the anti-proliferative response to G9a pharmacological inhibition correlates with MYC sensitivity and gene signatures. Consistently, genetically depleting G9a in vivo suppresses MYC-dependent tumor growth. These findings unveil G9a as an epigenetic regulator of MYC transcriptional repression and a therapeutic vulnerability in MYC-driven cancers.
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Affiliation(s)
- William B Tu
- Princess Margaret Cancer Centre, Toronto, ON M5G1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G1L7, Canada
| | - Yu-Jia Shiah
- Informatics and Biocomputing Program, Ontario Institute for Cancer Research, Toronto, ON M5G0A3, Canada
| | - Corey Lourenco
- Princess Margaret Cancer Centre, Toronto, ON M5G1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G1L7, Canada
| | - Peter J Mullen
- Princess Margaret Cancer Centre, Toronto, ON M5G1L7, Canada
| | | | - Cornelia Redel
- Princess Margaret Cancer Centre, Toronto, ON M5G1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G1L7, Canada
| | - Aaliya Tamachi
- Princess Margaret Cancer Centre, Toronto, ON M5G1L7, Canada
| | - Wail Ba-Alawi
- Princess Margaret Cancer Centre, Toronto, ON M5G1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G1L7, Canada
| | - Ahmed Aman
- Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, ON M5G0A3, Canada
| | - Rima Al-Awar
- Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, ON M5G0A3, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S1A8, Canada
| | - David W Cescon
- Princess Margaret Cancer Centre, Toronto, ON M5G1L7, Canada; Division of Medical Oncology and Hematology, Department of Medicine, University of Toronto, Toronto, ON M5G2C4, Canada
| | - Benjamin Haibe-Kains
- Princess Margaret Cancer Centre, Toronto, ON M5G1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G1L7, Canada
| | - Cheryl H Arrowsmith
- Princess Margaret Cancer Centre, Toronto, ON M5G1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G1L7, Canada; Structural Genomics Consortium, Toronto, ON M5G1L7, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, Toronto, ON M5G1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G1L7, Canada
| | - Paul C Boutros
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G1L7, Canada; Informatics and Biocomputing Program, Ontario Institute for Cancer Research, Toronto, ON M5G0A3, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S1A8, Canada
| | - Linda Z Penn
- Princess Margaret Cancer Centre, Toronto, ON M5G1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G1L7, Canada.
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41
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Rickman DS, Schulte JH, Eilers M. The Expanding World of N-MYC–Driven Tumors. Cancer Discov 2018; 8:150-163. [DOI: 10.1158/2159-8290.cd-17-0273] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 08/04/2017] [Accepted: 10/18/2017] [Indexed: 11/16/2022]
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42
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PAF1 complex component Leo1 helps recruit Drosophila Myc to promoters. Proc Natl Acad Sci U S A 2017; 114:E9224-E9232. [PMID: 29078288 DOI: 10.1073/pnas.1705816114] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Myc oncogene is a transcription factor with a powerful grip on cellular growth and proliferation. The physical interaction of Myc with the E-box DNA motif has been extensively characterized, but it is less clear whether this sequence-specific interaction is sufficient for Myc's binding to its transcriptional targets. Here we identify the PAF1 complex, and specifically its component Leo1, as a factor that helps recruit Myc to target genes. Since the PAF1 complex is typically associated with active genes, this interaction with Leo1 contributes to Myc targeting to open promoters.
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43
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Brägelmann J, Böhm S, Guthrie MR, Mollaoglu G, Oliver TG, Sos ML. Family matters: How MYC family oncogenes impact small cell lung cancer. Cell Cycle 2017; 16:1489-1498. [PMID: 28737478 DOI: 10.1080/15384101.2017.1339849] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Small cell lung cancer (SCLC) is one of the most deadly cancers and currently lacks effective targeted treatment options. Recent advances in the molecular characterization of SCLC has provided novel insight into the biology of this disease and raises hope for a paradigm shift in the treatment of SCLC. We and others have identified activation of MYC as a driver of susceptibility to Aurora kinase inhibition in SCLC cells and tumors that translates into a therapeutic option for the targeted treatment of MYC-driven SCLC. While MYC shares major features with its paralogs MYCN and MYCL, the sensitivity to Aurora kinase inhibitors is unique for MYC-driven SCLC. In this review, we will compare the distinct molecular features of the 3 MYC family members and address the potential implications for targeted therapy of SCLC.
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Affiliation(s)
- Johannes Brägelmann
- a Molecular Pathology, Institute of Pathology, University of Cologne , Cologne , Germany.,b Department of Translational Genomics , Medical Faculty, University of Cologne , Cologne , Germany
| | - Stefanie Böhm
- a Molecular Pathology, Institute of Pathology, University of Cologne , Cologne , Germany.,b Department of Translational Genomics , Medical Faculty, University of Cologne , Cologne , Germany
| | - Matthew R Guthrie
- c Department of Oncological Sciences , University of Utah, Huntsman Cancer Institute , Salt Lake City , UT , USA
| | - Gurkan Mollaoglu
- c Department of Oncological Sciences , University of Utah, Huntsman Cancer Institute , Salt Lake City , UT , USA
| | - Trudy G Oliver
- c Department of Oncological Sciences , University of Utah, Huntsman Cancer Institute , Salt Lake City , UT , USA
| | - Martin L Sos
- a Molecular Pathology, Institute of Pathology, University of Cologne , Cologne , Germany.,b Department of Translational Genomics , Medical Faculty, University of Cologne , Cologne , Germany.,d Center for Molecular Medicine Cologne , University of Cologne , Cologne , Germany
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44
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Allevato M, Bolotin E, Grossman M, Mane-Padros D, Sladek FM, Martinez E. Sequence-specific DNA binding by MYC/MAX to low-affinity non-E-box motifs. PLoS One 2017; 12:e0180147. [PMID: 28719624 PMCID: PMC5515408 DOI: 10.1371/journal.pone.0180147] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 06/09/2017] [Indexed: 01/07/2023] Open
Abstract
The MYC oncoprotein regulates transcription of a large fraction of the genome as an obligatory heterodimer with the transcription factor MAX. The MYC:MAX heterodimer and MAX:MAX homodimer (hereafter MYC/MAX) bind Enhancer box (E-box) DNA elements (CANNTG) and have the greatest affinity for the canonical MYC E-box (CME) CACGTG. However, MYC:MAX also recognizes E-box variants and was reported to bind DNA in a “non-specific” fashion in vitro and in vivo. Here, in order to identify potential additional non-canonical binding sites for MYC/MAX, we employed high throughput in vitro protein-binding microarrays, along with electrophoretic mobility-shift assays and bioinformatic analyses of MYC-bound genomic loci in vivo. We identified all hexameric motifs preferentially bound by MYC/MAX in vitro, which include the low-affinity non-E-box sequence AACGTT, and found that the vast majority (87%) of MYC-bound genomic sites in a human B cell line contain at least one of the top 21 motifs bound by MYC:MAX in vitro. We further show that high MYC/MAX concentrations are needed for specific binding to the low-affinity sequence AACGTT in vitro and that elevated MYC levels in vivo more markedly increase the occupancy of AACGTT sites relative to CME sites, especially at distal intergenic and intragenic loci. Hence, MYC binds diverse DNA motifs with a broad range of affinities in a sequence-specific and dose-dependent manner, suggesting that MYC overexpression has more selective effects on the tumor transcriptome than previously thought.
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Affiliation(s)
- Michael Allevato
- Department of Biochemistry, University of California Riverside, Riverside, California, United States of America
| | - Eugene Bolotin
- Department of Cell Biology and Neuroscience, University of California Riverside, Riverside, California, United States of America
| | - Mark Grossman
- Department of Biochemistry, University of California Riverside, Riverside, California, United States of America
| | - Daniel Mane-Padros
- Department of Cell Biology and Neuroscience, University of California Riverside, Riverside, California, United States of America
| | - Frances M. Sladek
- Department of Cell Biology and Neuroscience, University of California Riverside, Riverside, California, United States of America
- * E-mail: (E.M.); (F.M.S.)
| | - Ernest Martinez
- Department of Biochemistry, University of California Riverside, Riverside, California, United States of America
- * E-mail: (E.M.); (F.M.S.)
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45
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Jung LA, Gebhardt A, Koelmel W, Ade CP, Walz S, Kuper J, von Eyss B, Letschert S, Redel C, d'Artista L, Biankin A, Zender L, Sauer M, Wolf E, Evan G, Kisker C, Eilers M. OmoMYC blunts promoter invasion by oncogenic MYC to inhibit gene expression characteristic of MYC-dependent tumors. Oncogene 2017; 36:1911-1924. [PMID: 27748763 DOI: 10.1038/onc.2016.354] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 07/15/2016] [Accepted: 08/15/2016] [Indexed: 01/01/2023]
Abstract
MYC genes have both essential roles during normal development and exert oncogenic functions during tumorigenesis. Expression of a dominant-negative allele of MYC, termed OmoMYC, can induce rapid tumor regression in mouse models with little toxicity for normal tissues. How OmoMYC discriminates between physiological and oncogenic functions of MYC is unclear. We have solved the crystal structure of OmoMYC and show that it forms a stable homodimer and as such recognizes DNA in the same manner as the MYC/MAX heterodimer. OmoMYC attenuates both MYC-dependent activation and repression by competing with MYC/MAX for binding to chromatin, effectively lowering MYC/MAX occupancy at its cognate binding sites. OmoMYC causes the largest decreases in promoter occupancy and changes in expression on genes that are invaded by oncogenic MYC levels. A signature of OmoMYC-regulated genes defines subgroups with high MYC levels in multiple tumor entities and identifies novel targets for the eradication of MYC-driven tumors.
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Affiliation(s)
- L A Jung
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - A Gebhardt
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - W Koelmel
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - C P Ade
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - S Walz
- Comprehensive Cancer Center, Core Unit Bioinformatics, Biocenter, Würzburg, Germany
| | - J Kuper
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - B von Eyss
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - S Letschert
- Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, Würzburg, Germany
| | - C Redel
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - L d'Artista
- Division of Translational Gastrointestinal Oncology, Department of Internal Medicine I, University of Tübingen, Tübingen, Germany
| | - A Biankin
- Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Bearsden, Glasgow, UK
- West of Scotland Pancreatic Unit, Glasgow Royal Infirmary, Glasgow, UK
- South Western Sydney Clinical School, Faculty of Medicine, University of NSW, Liverpool, New South Wales, Australia
| | - L Zender
- Division of Translational Gastrointestinal Oncology, Department of Internal Medicine I, University of Tübingen, Tübingen, Germany
| | - M Sauer
- Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, Würzburg, Germany
| | - E Wolf
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - G Evan
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - C Kisker
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - M Eilers
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
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Maltais L, Montagne M, Bédard M, Tremblay C, Soucek L, Lavigne P. Biophysical characterization of the b-HLH-LZ of ΔMax, an alternatively spliced isoform of Max found in tumor cells: Towards the validation of a tumor suppressor role for the Max homodimers. PLoS One 2017; 12:e0174413. [PMID: 28350847 PMCID: PMC5370111 DOI: 10.1371/journal.pone.0174413] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/08/2017] [Indexed: 11/19/2022] Open
Abstract
It is classically recognized that the physiological and oncogenic functions of Myc proteins depend on specific DNA binding enabled by the dimerization of its C-terminal basic-region-Helix-Loop-Helix-Leucine Zipper (b-HLH-LZ) domain with that of Max. However, a new paradigm is emerging, where the binding of the c-Myc/Max heterodimer to non-specific sequences in enhancers and promoters drives the transcription of genes involved in diverse oncogenic programs. Importantly, Max can form a stable homodimer even in the presence of c-Myc and bind DNA (specific and non-specific) with comparable affinity to the c-Myc/Max heterodimer. Intriguingly, alterations in the Max gene by germline and somatic mutations or changes in the gene product by alternative splicing (e.g. ΔMax) were recently associated with pheochromocytoma and glioblastoma, respectively. This has led to the proposition that Max is, by itself, a tumor suppressor. However, the actual mechanism through which it exerts such an activity remains to be elucidated. Here, we show that contrary to the WT motif, the b-HLH-LZ of ΔMax does not homodimerize in the absence of DNA. In addition, although ΔMax can still bind the E-box sequence as a homodimer, it cannot bind non-specific DNA in that form, while it can heterodimerize with c-Myc and bind E-box and non-specific DNA as a heterodimer with high affinity. Taken together, our results suggest that the WT Max homodimer is important for attenuating the binding of c-Myc to specific and non-specific DNA, whereas ΔMax is unable to do so. Conversely, the splicing of Max into ΔMax could provoke an increase in overall chromatin bound c-Myc. According to the new emerging paradigm, the splicing event and the stark reduction in homodimer stability and DNA binding should promote tumorigenesis impairing the tumor suppressor activity of the WT homodimer of Max.
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Affiliation(s)
- Loïka Maltais
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
- PROTÉO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, Canada
| | - Martin Montagne
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
- PROTÉO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, Canada
| | - Mikaël Bédard
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
- PROTÉO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, Canada
| | - Cynthia Tremblay
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
- PROTÉO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, Canada
| | - Laura Soucek
- Vall d’Hebron Institute of Oncology (VHIO), Hospital Vall d’Hebron, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Pierre Lavigne
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
- PROTÉO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, Canada
- * E-mail:
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47
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Bédard M, Maltais L, Montagne M, Lavigne P. Miz-1 and Max compete to engage c-Myc: implication for the mechanism of inhibition of c-Myc transcriptional activity by Miz-1. Proteins 2016; 85:199-206. [PMID: 27859590 DOI: 10.1002/prot.25214] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 10/20/2016] [Accepted: 11/08/2016] [Indexed: 11/12/2022]
Abstract
c-Myc is a basic helix-loop-helix leucine zipper (b-HLH-LZ) transcription factor deregulated in the majority of human cancers. As a heterodimer with Max, another b-HLH-LZ transcription factor, deregulated and persistent c-Myc accumulates at transcriptionally active promoters and enhancers and amplifies transcription. This leads to the so-called transcriptional addiction of tumor cells. Recent studies have showed that c-Myc transcriptional activities can be reversed by its association with Miz-1, a POZ transcription factor containing 13 classical zinc fingers. Although evidences have led to suggest that c-Myc interacts with both Miz-1 and Max to form a ternary repressive complex, earlier evidences also suggest that Miz-1 and Max may compete to engage c-Myc. In such a scenario, the Miz-1/c-Myc complex would be the entity responsible for the inhibition of c-Myc transcriptional amplification. Considering the implications of the Miz-1/c-Myc interaction, it is highly important to solve this duality. While two potential c-Myc interacting domains (hereafter termed MID) have been identified in Miz-1 by yeast two-hybrid, with the b-HLH-LZ as a bait, the biophysical characterization of these interactions has not been reported so far. Here, we report that the MID located between the 12th and 13th zinc finger of Miz-1 and the b-HLH-LZ of Max compete to form a complex with the b-HLH-LZ of c-Myc. Our results support the notion that the repressive action of Miz-1 on c-Myc does not rely on the formation of a ternary complex. The implications of these observations for the mechanism of inhibition of c-Myc transcriptional activity by Miz-1 are discussed. Proteins 2017; 85:199-206. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Mikaël Bédard
- Département de Biochimie, Institut de Pharmacologie de Sherbrooke, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, J1H 5N4, Canada.,PROTEO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, G1V 0A6, Canada.,GRASP; Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Québec, H3G 0B1, Canada
| | - Loïka Maltais
- Département de Biochimie, Institut de Pharmacologie de Sherbrooke, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, J1H 5N4, Canada.,PROTEO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, G1V 0A6, Canada.,GRASP; Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Québec, H3G 0B1, Canada
| | - Martin Montagne
- Département de Biochimie, Institut de Pharmacologie de Sherbrooke, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, J1H 5N4, Canada.,PROTEO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, G1V 0A6, Canada.,GRASP; Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Québec, H3G 0B1, Canada
| | - Pierre Lavigne
- Département de Biochimie, Institut de Pharmacologie de Sherbrooke, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, J1H 5N4, Canada.,PROTEO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, G1V 0A6, Canada.,GRASP; Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Québec, H3G 0B1, Canada
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48
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Willmer T, Peres J, Mowla S, Abrahams A, Prince S. The T-Box factor TBX3 is important in S-phase and is regulated by c-Myc and cyclin A-CDK2. Cell Cycle 2016; 14:3173-83. [PMID: 26266831 DOI: 10.1080/15384101.2015.1080398] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The transcription factor, TBX3, is critical for the formation of, among other structures, the heart, limbs and mammary glands and haploinsufficiency of the human TBX3 gene result in ulnar-mammary syndrome which is characterized by hypoplasia of these structures. On the other hand, the overexpression of TBX3 is a feature of a wide range of cancers and it has been implicated in several aspects of the oncogenic process. This includes its ability to function as an immortalizing gene and to promote proliferation through actively repressing negative cell cycle regulators. Together this suggests that TBX3 levels may need to be tightly regulated during the cell cycle. Here we demonstrate that this is indeed the case and that TBX3 mRNA and protein levels peak at S-phase and that the TBX3 protein is predominantly localized to the nucleus of S-phase cells. The increased levels of TBX3 in S-phase are shown to occur transcriptionally through activation by c-Myc at E-box motifs located at -1210 and -701 bps and post-translationally by cyclin A-CDK2 phosphorylation. Importantly, when TBX3 is depleted by shRNA the cells accumulate in S-phase. These results suggest that TBX3 is required for cells to transit through S-phase and that this function may be linked to its role as a pro-proliferative factor.
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Affiliation(s)
- Tarryn Willmer
- a Department of Human Biology ; Faculty of Health Sciences; University of Cape Town ; Cape Town , South Africa
| | - Jade Peres
- a Department of Human Biology ; Faculty of Health Sciences; University of Cape Town ; Cape Town , South Africa
| | - Shaheen Mowla
- a Department of Human Biology ; Faculty of Health Sciences; University of Cape Town ; Cape Town , South Africa
| | - Amaal Abrahams
- a Department of Human Biology ; Faculty of Health Sciences; University of Cape Town ; Cape Town , South Africa
| | - Sharon Prince
- a Department of Human Biology ; Faculty of Health Sciences; University of Cape Town ; Cape Town , South Africa
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49
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Abstract
Altering the ability of the MYC transcription factor to bind to individual genes can customize the global gene expression output of cells.
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Affiliation(s)
- Ying Zheng
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, Bethesda, United States
| | - David Levens
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, Bethesda, United States
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50
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Lorenzin F, Benary U, Baluapuri A, Walz S, Jung LA, von Eyss B, Kisker C, Wolf J, Eilers M, Wolf E. Different promoter affinities account for specificity in MYC-dependent gene regulation. eLife 2016; 5. [PMID: 27460974 PMCID: PMC4963202 DOI: 10.7554/elife.15161] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 06/13/2016] [Indexed: 12/21/2022] Open
Abstract
Enhanced expression of the MYC transcription factor is observed in the majority of tumors. Two seemingly conflicting models have been proposed for its function: one proposes that MYC enhances expression of all genes, while the other model suggests gene-specific regulation. Here, we have explored the hypothesis that specific gene expression profiles arise since promoters differ in affinity for MYC and high-affinity promoters are fully occupied by physiological levels of MYC. We determined cellular MYC levels and used RNA- and ChIP-sequencing to correlate promoter occupancy with gene expression at different concentrations of MYC. Mathematical modeling showed that binding affinities for interactions of MYC with DNA and with core promoter-bound factors, such as WDR5, are sufficient to explain promoter occupancies observed in vivo. Importantly, promoter affinity stratifies different biological processes that are regulated by MYC, explaining why tumor-specific MYC levels induce specific gene expression programs and alter defined biological properties of cells. DOI:http://dx.doi.org/10.7554/eLife.15161.001 Genes with the potential to cause tumors and cancer are commonly called oncogenes. One example of an oncogene encodes for a protein called MYC and many tumors contain high levels of this protein. MYC is a transcription factor and studies of aggressive tumors suggested that, like most other transcription factors, MYC binds to and regulates the activity of a small number of genes in tumors. However, other studies went on to show that MYC actually binds to thousands of genes and somehow only regulates a subset of them during tumor development. Lorenzin et al. set out to understand how this process works by generating human cells in which the concentration of MYC protein could be altered. In the experiments, the concentration was varied from normal healthy levels to the high levels found in aggressive tumors. The amount of MYC bound to genes and the extent to which it activated the genes inside these cells was also measured. Lorenzin et al. found that increasing MYC levels from normal to tumor-specific levels did not affect MYC binding at genes where the transcription factor was already strongly bound in normal cells. Rather, MYC binding increased only at genes that were weakly bound in normal cells. Consistent with this observation, only genes at which MYC was weakly bound in normal cells were activated by increasing MYC levels. This observation suggests that increasing the concentration of MYC protein from normal to tumor-specific levels “fills up” previously empty binding sites around these genes with the transcription factor. Lorenzin et al. also used mathematical modeling to understand how the concentrations of MYC in normal and tumor cells might explain how MYC behaves in cells. Together, the results imply that the MYC transcription factor regulates distinct sets of genes in normal and tumor cells according to how much MYC is present. Further studies may show that the altered regulation of a tumor-specific set of genes is important for tumor development and could use this new information to identify new targets for treating MYC-driven tumors. DOI:http://dx.doi.org/10.7554/eLife.15161.002
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Affiliation(s)
- Francesca Lorenzin
- Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Uwe Benary
- Group Mathematical Modeling of Cellular Processes, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | - Apoorva Baluapuri
- Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Susanne Walz
- Core Unit Bioinformatics, Biocenter, University of Würzburg, Würzburg, Germany.,Comprehensive Cancer Center Mainfranken, University of Würzburg, Würzburg, Germany
| | - Lisa Anna Jung
- Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Würzburg, Germany.,Rudolf-Virchow-Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Björn von Eyss
- Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Caroline Kisker
- Rudolf-Virchow-Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Jana Wolf
- Group Mathematical Modeling of Cellular Processes, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | - Martin Eilers
- Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Würzburg, Germany.,Comprehensive Cancer Center Mainfranken, University of Würzburg, Würzburg, Germany
| | - Elmar Wolf
- Department of Biochemistry and Molecular Biology, Biocenter, University of Würzburg, Würzburg, Germany
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