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Land G, Van Haeringen B, Cooper C, Andelkovic V, O'Rourke T. A Rare Case of Rhabdoid Pancreatic Carcinoma: Prolonged Disease-Free Survival Following Upfront Resection and Adjuvant Chemotherapy. Cureus 2023; 15:e50145. [PMID: 38186431 PMCID: PMC10771581 DOI: 10.7759/cureus.50145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2023] [Indexed: 01/09/2024] Open
Abstract
The rhabdoid subtype of undifferentiated pancreatic carcinoma is rarely reported. The clinical course of this disease is therefore poorly understood, although it is apparently an aggressive malignancy. We herein discuss the case of a 69-year-old man presenting with a rapidly enlarging mass of the pancreatic body and tail who was diagnosed with locally advanced SMARCB1-deficient undifferentiated pancreatic carcinoma with rhabdoid features, treated with radical resection and adjuvant chemotherapy, and has achieved 18-month disease-free survival ongoing at the time of article publication. We identify and contrast our case with 15 similar tumors reported in the English literature, briefly discuss the biology of this tumor, its relationship to malignant rhabdoid tumors of childhood, the role of SMARCB1 and its parent complex switch/sucrose-non-fermentable chromatin remodeling complex (SWI/SNF) in modulating the behavior of pancreatic malignancy, and the potential therapeutic avenues available for SWI/SNF-mutated malignancies.
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Affiliation(s)
- Gabriel Land
- General Surgery, Princess Alexandra Hospital, Brisbane, AUS
| | | | - Caroline Cooper
- Anatomical Pathology, Princess Alexandra Hospital, Brisbane, AUS
| | | | - Thomas O'Rourke
- Hepatobiliary Surgery, Princess Alexandra Hospital, Brisbane, AUS
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2
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Ramachandran J, Chen W, Lex RK, Windsor KE, Lee H, Wang T, Zhou W, Ji H, Vokes SA. The BAF chromatin complex component SMARCC1 does not mediate GLI transcriptional repression of Hedgehog target genes in limb buds. bioRxiv 2023:2023.02.03.527038. [PMID: 36798239 PMCID: PMC9934545 DOI: 10.1101/2023.02.03.527038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Transcriptional responses to the Hedgehog (HH) signaling pathway are primarily modulated by GLI repression in the mouse limb. Previous studies suggested a role for the BAF chromatin remodeling complex in mediating GLI repression. Consistent with this possibility, the core BAF complex protein SMARCC1 is present at most active limb enhancers including the majority of GLI enhancers. However, in contrast to GLI repression which reduces chromatin accessibility, SMARCC1 maintains chromatin accessibility at most enhancers, including those bound by GLI. Moreover, SMARCC1 binding at GLI-regulated enhancers occurs independently of GLI3. Consistent with previous studies, some individual GLI target genes are mis-regulated in Smarcc1 conditional knockouts, though most GLI target genes are unaffected. Moreover, SMARCC1 is not necessary for mediating constitutive GLI repression in HH mutant limb buds. We conclude that SMARCC1 does not mediate GLI3 repression, which we propose utilizes alternative chromatin remodeling complexes.
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Affiliation(s)
- Janani Ramachandran
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street Stop A5000, Austin, TX 78712 USA
| | - Wanlu Chen
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Rachel K. Lex
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street Stop A5000, Austin, TX 78712 USA
| | - Kathryn E. Windsor
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street Stop A5000, Austin, TX 78712 USA
| | - Hyunji Lee
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street Stop A5000, Austin, TX 78712 USA
| | - Tingchang Wang
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Weiqiang Zhou
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Hongkai Ji
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Steven A. Vokes
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street Stop A5000, Austin, TX 78712 USA
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Lalaoui Rachidi S, Firmin N, Elfadli M, Essadi I, Belbaraka R. A Case Report of SMARCA4-Deficient Thoracic Sarcoma: A Rare and Aggressive Disease With a Grim Prognosis. Cureus 2023; 15:e39571. [PMID: 37378131 PMCID: PMC10292728 DOI: 10.7759/cureus.39571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2023] [Indexed: 06/29/2023] Open
Abstract
SMARCA4-deficient thoracic sarcoma (DTS) is a rare malignancy defined by inactivating SMARCA4 mutations leading to protein loss. It was recently described as an aggressive disease with a dismal prognosis, mostly affecting young men with a history of heavy smoking. Histologically, SMARCA4-DTS is a poorly differentiated tumor with rhabdoid or epithelioid features that can be distinguished from other soft tissue, and thoracic sarcomas by a higher tumor mutation burden (TMB) and the presence of smoking signatures, including KRAS, STK11, and KEAP1 mutations. Currently, there is no approved treatment for SMARCA4-DTS, which is known to be chemo-resistant, but more recent studies have shown some effectiveness with immune checkpoint inhibitors. We report the case of a 42-year-old man with a family history of cancer who was admitted to the hospital with acute respiratory distress and superior vena cava syndrome. He had been experiencing thoracic pain, dry cough, dyspnea, fatigue, and unintentional weight loss for a month. Imaging revealed multiple masses and lymph nodes in the chest, as well as pleural effusion. PET scan showed widespread metastases. A cervical lymph node biopsy confirmed the diagnosis of SMARCA4-deficient thoracic sarcoma. Unfortunately, his general condition did not allow an aggressive treatment. He was started on Pazopanib 800mg per day, but deteriorated rapidly and passed away. This report highlights the aggressive nature and unfavorable prognosis associated with SMARCA4-deficient thoracic sarcoma. Accurate diagnosis of this entity can be challenging due to its unique marker expression and unfamiliar histological features. Currently, there are no established treatment strategies for this condition; however, recent studies have shown promising results with immune checkpoint inhibitors and targeted therapies. Further research is necessary to identify the most effective treatment approaches for SMARCA4-DTS.
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Affiliation(s)
| | - Nelly Firmin
- Medical Oncology, Montpellier Cancer Institute (ICM), Montpellier, FRA
| | - Mohamed Elfadli
- Medical Oncology, Mohammed VI University Hospital, Marrakesh, MAR
| | - Ismail Essadi
- Medical Oncology, Ibn Sina Military Teaching Hospital Marrakesh, Marrakesh, MAR
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4
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Gao X, Wang C, Abdelrahman S, Kady N, Murga-Zamalloa C, Gann P, Sverdlov M, Wolfe A, Polk A, Brown N, Bailey NG, Inamdar K, Casavilca S, Montes J, Barrionuevo C, Taxa L, Reneau J, Siebel CW, Maillard I, Wilcox RA. Notch Signaling Promotes Mature T-Cell Lymphomagenesis. Cancer Res 2022; 82:3763-3773. [PMID: 36006995 PMCID: PMC9588752 DOI: 10.1158/0008-5472.can-22-1215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/15/2022] [Accepted: 08/22/2022] [Indexed: 01/26/2023]
Abstract
Peripheral T-cell lymphomas (PTCL) are agressive lymphomas that develop from mature T cells. The most common PTCLs are genetically, molecularly, and clinically diverse and are generally associated with dismal outcomes. While Notch signaling plays a critically important role in both the development of immature T cells and their malignant transformation, its role in PTCL is poorly understood, despite the increasingly appreciated function of Notch in regulating the proliferation and differentiation of mature T cells. Here, we demonstrate that Notch receptors and their Delta-like family ligands (DLL1/DLL4) play a pathogenic role in PTCL. Notch1 activation was observed in common PTCL subtypes, including PTCL-not otherwise specified (NOS). In a large cohort of PTCL-NOS biopsies, Notch1 activation was significantly associated with surrogate markers of proliferation. Complementary genetically engineered mouse models and spontaneous PTCL models were used to functionally examine the role of Notch signaling, and Notch1/Notch2 blockade and pan-Notch blockade using dominant-negative MAML significantly impaired the proliferation of malignant T cells and PTCL progression in these models. Treatment with DLL1/DLL4 blocking antibodies established that Notch signaling is ligand-dependent. Together, these findings reveal a role for ligand-dependent Notch signaling in driving peripheral T-cell lymphomagenesis. SIGNIFICANCE This work demonstrates that ligand-dependent Notch activation promotes the growth and proliferation of mature T-cell lymphomas, providing new therapeutic strategies for this group of aggressive lymphomas.
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Affiliation(s)
- Xin Gao
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI
| | - Chenguang Wang
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI
| | - Suhaib Abdelrahman
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI
| | - Nermin Kady
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI
| | | | - Peter Gann
- Department of Pathology, University of Illinois Chicago, Chicago, IL
| | - Maria Sverdlov
- Department of Pathology, University of Illinois Chicago, Chicago, IL
| | - Ashley Wolfe
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI
| | - Avery Polk
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI
| | - Noah Brown
- Department of Pathology, University of Michigan, Ann Arbor, MI
| | | | - Kedar Inamdar
- Department of Pathology, Henry Ford Hospital, Detroit, MI
| | - Sandro Casavilca
- Department of Pathology, Instituto Nacional de Enfermedades Neoplasicas (INEN), Lima, Peru
| | - Jaime Montes
- Department of Pathology, Instituto Nacional de Enfermedades Neoplasicas (INEN), Lima, Peru
| | - Carlos Barrionuevo
- Department of Pathology, Instituto Nacional de Enfermedades Neoplasicas (INEN), Lima, Peru
| | - Luis Taxa
- Department of Pathology, Instituto Nacional de Enfermedades Neoplasicas (INEN), Lima, Peru
| | - John Reneau
- Department of Medicine, Division of Hematology, The Ohio State University Comprehensive Cancer Center, Columbus, OH
| | | | - Ivan Maillard
- Department of Medicine, Division of Hematology/Oncology, University of Pennsylvania, Philadelphia, PA
| | - Ryan A. Wilcox
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI
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5
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Bharathy N, Cleary MM, Kim JA, Nagamori K, Crawford KA, Wang E, Saha D, Settelmeyer TP, Purohit R, Skopelitis D, Chang K, Doran JA, Kirschbaum CW, Bharathy S, Crews DW, Randolph ME, Karnezis AN, Hudson-Price L, Dhawan J, Michalek JE, Ciulli A, Vakoc CR, Keller C. SMARCA4 biology in alveolar rhabdomyosarcoma. Oncogene 2022; 41:1647-1656. [PMID: 35094009 PMCID: PMC9985831 DOI: 10.1038/s41388-022-02205-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 12/21/2021] [Accepted: 01/20/2022] [Indexed: 11/09/2022]
Abstract
Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and phenocopies a muscle precursor that fails to undergo terminal differentiation. The alveolar subtype (ARMS) has the poorest prognosis and represents the greatest unmet medical need for RMS. Emerging evidence supports the role of epigenetic dysregulation in RMS. Here we show that SMARCA4/BRG1, an ATP-dependent chromatin remodeling enzyme of the SWI/SNF complex, is prominently expressed in primary tumors from ARMS patients and cell cultures. Our validation studies for a CRISPR screen of 400 epigenetic targets identified SMARCA4 as a unique factor for long-term (but not short-term) tumor cell survival in ARMS. A SMARCA4/SMARCA2 protein degrader (ACBI-1) demonstrated similar long-term tumor cell dependence in vitro and in vivo. These results credential SMARCA4 as a tumor cell dependency factor and a therapeutic target in ARMS.
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Affiliation(s)
- Narendra Bharathy
- Children’s Cancer Therapy Development Institute, Beaverton, OR 97005 USA,Present Address: Gene Therapy Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA 19104 USA
| | - Megan M. Cleary
- Children’s Cancer Therapy Development Institute, Beaverton, OR 97005 USA
| | - Jin-Ah Kim
- Children’s Cancer Therapy Development Institute, Beaverton, OR 97005 USA
| | - Kiyo Nagamori
- Children’s Cancer Therapy Development Institute, Beaverton, OR 97005 USA
| | | | - Eric Wang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 USA
| | - Debarya Saha
- Children’s Cancer Therapy Development Institute, Beaverton, OR 97005 USA,CSIR-CCMB, Uppal Road, Hyderabad 500007 India
| | | | - Reshma Purohit
- Children’s Cancer Therapy Development Institute, Beaverton, OR 97005 USA
| | | | - Kenneth Chang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 USA
| | - Jessica A. Doran
- Children’s Cancer Therapy Development Institute, Beaverton, OR 97005 USA
| | - C. Ward Kirschbaum
- Children’s Cancer Therapy Development Institute, Beaverton, OR 97005 USA
| | - Suriya Bharathy
- Children’s Cancer Therapy Development Institute, Beaverton, OR 97005 USA
| | - Davis W. Crews
- Children’s Cancer Therapy Development Institute, Beaverton, OR 97005 USA
| | | | - Anthony N. Karnezis
- University of California C Davis Medical Center, Sacramento, CA 95817 USA,British Columbia Cancer Research Center, Vancouver, BC V5Z 1L3 Canada
| | - Lisa Hudson-Price
- Children’s Cancer Therapy Development Institute, Beaverton, OR 97005 USA
| | | | - Joel E. Michalek
- Department of Epidemiology and Biostatistics, University of Texas Health Science Center, San Antonio, TX 78229 USA
| | - Alessio Ciulli
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK.
| | | | - Charles Keller
- Children's Cancer Therapy Development Institute, Beaverton, OR, 97005, USA.
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6
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Soshnikova N, Tatarskiy E, Tatarskiy V, Klimenko N, Shtil AA, Nikiforov M, Georgieva S. PHF10 subunit of PBAF complex mediates transcriptional activation by MYC. Oncogene 2021; 40:6071-6080. [PMID: 34465901 PMCID: PMC8863208 DOI: 10.1038/s41388-021-01994-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 07/24/2021] [Accepted: 08/10/2021] [Indexed: 02/08/2023]
Abstract
The PBAF complex, a member of SWI/SNF family of chromatin remodelers, plays an essential role in transcriptional regulation. We revealed a disease progression associated elevation of PHF10 subunit of PBAF in clinical melanoma samples. In melanoma cell lines, PHF10 interacts with MYC and facilitates the recruitment of PBAF complex to target gene promoters, therefore, augmenting MYC transcriptional activation of genes involved in the cell cycle progression. Depletion of either PHF10 or MYC induced G1 accumulation and a senescence-like phenotype. Our data identify PHF10 as a pro-oncogenic mechanism and an essential novel link between chromatin remodeling and MYC-dependent gene transcription.
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Affiliation(s)
- N.V. Soshnikova
- Department of Eukaryotic Transcription Factors, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilov Street, Moscow 119991, Russia,Corresponding authors: (N.V.Soshnikova); (S.G.Georgieva)
| | - E.V. Tatarskiy
- Department of Eukaryotic Transcription Factors, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - V.V. Tatarskiy
- Laboratory of Molecular Oncobiology, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - N.S. Klimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - A. A. Shtil
- Laboratory of Molecular Oncobiology, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - M.A. Nikiforov
- Department of Cancer Biology, Wake Forest University, Medical Center Drive, Winston-Salem, NC 27101, USA
| | - S.G. Georgieva
- Department of Eukaryotic Transcription Factors, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia,Department of Transcription Factors, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilov Street, Moscow 119991, Russia,Corresponding authors: (N.V.Soshnikova); (S.G.Georgieva)
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7
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Moreno T, Monterde B, González-Silva L, Betancor-Fernández I, Revilla C, Agraz-Doblas A, Freire J, Isidro P, Quevedo L, Blanco R, Montes-Moreno S, Cereceda L, Astudillo A, Casar B, Crespo P, Morales Torres C, Scaffidi P, Gómez-Román J, Salido E, Varela I. ARID2 deficiency promotes tumor progression and is associated with higher sensitivity to chemotherapy in lung cancer. Oncogene 2021; 40:2923-2935. [PMID: 33742126 PMCID: PMC7610680 DOI: 10.1038/s41388-021-01748-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/23/2021] [Accepted: 03/04/2021] [Indexed: 12/26/2022]
Abstract
The survival rate in lung cancer remains stubbornly low and there is an urgent need for the identification of new therapeutic targets. In the last decade, several members of the SWI/SNF chromatin remodeling complexes have been described altered in different tumor types. Nevertheless, the precise mechanisms of their impact on cancer progression, as well as the application of this knowledge to cancer patient management are largely unknown. In this study, we performed targeted sequencing of a cohort of lung cancer patients on genes involved in chromatin structure. In addition, we studied at the protein level the expression of these genes in cancer samples and performed functional experiments to identify the molecular mechanisms linking alterations of chromatin remodeling genes and tumor development. Remarkably, we found that 20% of lung cancer patients show ARID2 protein loss, partially explained by the presence of ARID2 mutations. In addition, we showed that ARID2 deficiency provokes profound chromatin structural changes altering cell transcriptional programs, which bolsters the proliferative and metastatic potential of the cells both in vitro and in vivo. Moreover, we demonstrated that ARID2 deficiency impairs DNA repair, enhancing the sensitivity of the cells to DNA-damaging agents. Our findings support that ARID2 is a bona fide tumor suppressor gene in lung cancer that may be exploited therapeutically.
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Affiliation(s)
- Thaidy Moreno
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC, Santander, Spain
| | - Beatriz Monterde
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC, Santander, Spain
| | - Laura González-Silva
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC, Santander, Spain
| | - Isabel Betancor-Fernández
- Departamento de Patología, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Tenerife, Spain
| | - Carlos Revilla
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC, Santander, Spain
| | - Antonio Agraz-Doblas
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC, Santander, Spain
| | - Javier Freire
- Servicio de Anatomía Patológica y Biobanco Valdecilla, HUMV/IDIVAL, Santander, Spain
| | - Pablo Isidro
- Biobanco del Principado de Asturias (BBPA), Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Laura Quevedo
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC, Santander, Spain
| | - Rosa Blanco
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC, Santander, Spain
| | | | - Laura Cereceda
- Servicio de Anatomía Patológica y Biobanco Valdecilla, HUMV/IDIVAL, Santander, Spain
| | - Aurora Astudillo
- Biobanco del Principado de Asturias (BBPA), Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Berta Casar
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC, Santander, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain
| | - Piero Crespo
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC, Santander, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain
| | | | - Paola Scaffidi
- Cancer Epigenetics Laboratory, The Francis Crick Institute, London, UK
| | - Javier Gómez-Román
- Servicio de Anatomía Patológica y Biobanco Valdecilla, HUMV/IDIVAL, Santander, Spain
| | - Eduardo Salido
- Departamento de Patología, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Tenerife, Spain
| | - Ignacio Varela
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC, Santander, Spain.
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Singh M, Singh H, Hambro B, Kaur J, Rao R. Integrase Interactor 1 (INI-1) Deficient Renal Cell Carcinoma. Cureus 2021; 13:e13082. [PMID: 33680622 PMCID: PMC7932046 DOI: 10.7759/cureus.13082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Members of the SWItch/sucrose nonfermentable (SWI-SNF) family, including SWI/SNF related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4 (SMARCA4), SWI/SNF related, matrix‐associated, actin‐dependent regulator of chromatin, subfamily B member 1 (SMARCB1)/integrase interactor 1 (INI-1) are known tumor suppressor genes. Interactions between SMARCB1/INI-1 and key protein components in various cellular pathways are related to tumor progression and proliferation.SMARCB1/INI-1 protein was undetectable in rhabdoid tumor cells, whereas non-tumorous cells express the SMARCB1/INI-1 genes. Germline and sporadic mutations of several genes encoding for proteins in this complex are known to cause a spectrum of cancers, usually with sarcomatoid features which include a very aggressive renal medullary carcinoma. We report a case of a 29-year-old male who presented with SMARCA4 deficient renal tumor with a very aggressive clinical behavior which ultimately led to his death.
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Affiliation(s)
| | | | | | - Jasleen Kaur
- Internal Medicine, St Agnes Medical Center, Fresno, USA
| | - Ravi Rao
- Hematology and Oncology, St Agnes Medical Center, Fresno, USA
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9
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Bluemn T, Schmitz J, Chen Y, Zheng Y, Zhang Y, Zheng S, Burns R, DeJong J, Christiansen L, Izaguirre-Carbonell J, Wang D, Zhu N. Arid2 regulates hematopoietic stem cell differentiation in normal hematopoiesis. Exp Hematol 2021; 94:37-46. [PMID: 33346030 PMCID: PMC10041880 DOI: 10.1016/j.exphem.2020.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 12/11/2020] [Accepted: 12/13/2020] [Indexed: 01/25/2023]
Abstract
The switch/sugar nonfermenting (SWI/SNF) family of chromatin remodeling complexes have been implicated in normal hematopoiesis. The ARID2 protein is a component of the polybromo-associated BAF (PBAF), one of the two main SWI/SNF complexes. In the current study, we used a conditional Arid2 knockout mouse model to determine its role in normal hematopoiesis. We found that the loss of Arid2 has no discernable effects on steady-state hematopoiesis, with the exception of a modest effect on erythropoiesis. On bone marrow transplantation, however, the loss of Arid2 affects HSC differentiation in a cell-autonomous manner, resulting in significant decreases in the ability to reconstitute the lymphoid lineage. Gene expression analysis of Arid2 knockout cells revealed enrichment of myeloid-biased multipotent progenitor (MPP) cell signatures, while the lymphoid-biased MPPs are enriched in the wild type, consistent with the observed phenotype. Moreover, Arid2 knockout cells revealed enrichment of inflammatory pathways with upregulation of TLR receptors, as well as downstream signaling cascade genes. Furthermore, under lymphocyte-biased growth conditions in vitro, Arid2 null bone marrow cells have significantly impaired proliferation, which decreased further on lipopolysaccharide stimulation. Overall, these data suggest that the loss of Arid2 impairs HSC differentiation ability, and this effect may be mediated through upregulation of inflammatory pathways.
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Affiliation(s)
- Theresa Bluemn
- Blood Research Institute, Versiti, Milwaukee, WI; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI
| | | | - Yuhong Chen
- Blood Research Institute, Versiti, Milwaukee, WI
| | | | | | - Shikan Zheng
- Blood Research Institute, Versiti, Milwaukee, WI
| | - Robert Burns
- Blood Research Institute, Versiti, Milwaukee, WI
| | | | - Luke Christiansen
- Blood Research Institute, Versiti, Milwaukee, WI; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI
| | | | - Demin Wang
- Blood Research Institute, Versiti, Milwaukee, WI; Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI
| | - Nan Zhu
- Blood Research Institute, Versiti, Milwaukee, WI; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI.
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10
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Abstract
Prion and prion-like phenomena are involved in the pathology of numerous human neurodegenerative diseases. The budding yeast, Saccharomyces cerevisiae, has a number of endogenous yeast prions-epigenetic elements that are transmitted as altered protein conformations and often manifested as heritable phenotypic traits. One such yeast prion, [SWI+], was discovered and characterized by our laboratory. The protein determinant of [SWI+], Swi1 was found to contain an amino-terminal, asparagine-rich prion domain. Normally, Swi1 functions as part of the SWI/SNF chromatin remodeling complex, thus, acting as a global transcriptional regulator. Consequently, prionization of Swi1 leads to a variety of phenotypes including poor growth on non-glucose carbon sources and abolishment of multicellular features-with implications on characterization of [SWI+] as being detrimental or beneficial to yeast. The study of [SWI+] has revealed important knowledge regarding the chaperone systems supporting prion propagation as well as prion-prion interactions with [PSI+] and [RNQ+]. Additionally, an intricate regulatory network involving [SWI+] and other prion elements governing multicellular features in yeast has begun to be revealed. In this review, we discuss the current understanding of [SWI+] in addition to some possibilities for future study.
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Affiliation(s)
- Dustin K Goncharoff
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, 320 E Superior St, Searle 7-625, Chicago, IL 60611, USA
| | - Zhiqiang Du
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, 320 E Superior St, Searle 7-625, Chicago, IL 60611, USA
| | - Liming Li
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, 320 E Superior St, Searle 7-625, Chicago, IL 60611, USA
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11
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Marquez-Vilendrer SB, Rai SK, Gramling SJ, Lu L, Reisman DN. BRG1 and BRM loss selectively impacts RB and P53, respectively: BRG1 and BRM have differential functions in vivo. Oncoscience 2016; 3:337-350. [PMID: 28105458 PMCID: PMC5235922 DOI: 10.18632/oncoscience.333] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 09/23/2016] [Indexed: 12/11/2022] Open
Abstract
The SWI/SNF complex is an important regulator of gene expression that functions by interacting with a diverse array of cellular proteins. The catalytic subunits of SWI/SNF, BRG1 and BRM, are frequently lost alone or concomitantly in a range of different cancer types. This loss abrogates SWI/SNF complex function as well as the functions of proteins that are required for SWI/SNF function, such as RB1 and TP53. Yet while both proteins are known to be dependent on SWI/SNF, we found that BRG1, but not BRM, is functionally linked to RB1, such that loss of BRG1 can directly or indirectly inactivate the RB1 pathway. This newly discovered dependence of RB1 on BRG1 is important because it explains why BRG1 loss can blunt the growth-inhibitory effect of tyrosine kinase inhibitors (TKIs). We also observed that selection for Trp53 mutations occurred in Brm-positive tumors but did not occur in Brm-negative tumors. Hence, these data indicate that, during cancer development, Trp53 is functionally dependent on Brm but not Brg1. Our findings show for the first time the key differences in Brm- and Brg1-specific SWI/SNF complexes and help explain why concomitant loss of Brg1 and Brm frequently occurs in cancer, as well as how their loss impacts cancer development.
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Affiliation(s)
| | - Sudhir K Rai
- Department of Hematology/Oncology, Medicine, University of Florida, Gainesville, FL, USA
| | - Sarah Jb Gramling
- Department of Hematology/Oncology, Medicine, University of Florida, Gainesville, FL, USA
| | - Li Lu
- Department of Hematology/Oncology, Medicine, University of Florida, Gainesville, FL, USA; Department of Pathology, University of Florida, Gainesville, FL, USA
| | - David N Reisman
- Department of Hematology/Oncology, Medicine, University of Florida, Gainesville, FL, USA
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12
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Marquez-Vilendrer SB, Rai SK, Gramling SJ, Lu L, Reisman DN. Loss of the SWI/SNF ATPase subunits BRM and BRG1 drives lung cancer development. Oncoscience 2016; 3:322-336. [PMID: 28105457 PMCID: PMC5235921 DOI: 10.18632/oncoscience.323] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 09/23/2016] [Indexed: 12/24/2022] Open
Abstract
Inactivation of Brg1 and Brm accelerated lung tumor development, shortened tumor latency, and caused a loss of differentiation. Tumors with Brg1 and/or Brm loss recapitulated the evolution of human lung cancer as observed by the development of local tumor invasion as well as distal tumor metastasis, thereby making this model useful in lung cancer studies. Brg1 loss contributed to metastasis in part by driving E-cadherin loss and Vimentin up-regulation. By changing more than 6% of the murine genome with the down-regulation of tumor suppressors, DNA repair, differentiation and cell adhesion genes, and the concomitant up-regulation of oncogenes, angiogenesis, metastasis and antiapoptosis genes, caused by the dual loss of Brg1/Brm further accelerated tumor development. Additionally, this Brg1/Brm-driven change in gene expression resulted in a nearly two-fold increase in tumorigenicity in Brg1/Brm knockout mice compared with wild type mice. Most importantly, Brg1/Brm-driven lung cancer development histologically and clinically reflects human lung cancer development thereby making this GEMM model potentially useful.
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Affiliation(s)
| | - Sudhir K Rai
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Florida, USA
| | - Sarah Jb Gramling
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Florida, USA
| | - Li Lu
- Department of Pathology, University of Florida, Florida, USA
| | - David N Reisman
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Florida, USA
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13
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Karnezis AN, Hoang LN, Coatham M, Ravn S, Almadani N, Tessier-Cloutier B, Irving J, Meng B, Li X, Chow C, McAlpine J, Kuo KT, Mao TL, Djordjevic B, Soslow RA, Huntsman DG, Blake Gilks C, Köbel M, Lee CH. Loss of switch/sucrose non-fermenting complex protein expression is associated with dedifferentiation in endometrial carcinomas. Mod Pathol 2016; 29:302-14. [PMID: 26743474 DOI: 10.1038/modpathol.2015.155] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/20/2015] [Indexed: 12/12/2022]
Abstract
Dedifferentiated endometrial carcinoma is an aggressive type of endometrial cancer that contains a mix of low-grade endometrioid and undifferentiated carcinoma components. We performed targeted sequencing of eight dedifferentiated carcinomas and identified somatic frameshift/nonsense mutations in SMARCA4, a core ATPase of the switch/sucrose non-fermenting (SWI/SNF) complex, in the undifferentiated components of four tumors. Immunohistochemical analysis confirmed the loss of SMARCA4 in the undifferentiated component of these four SMARCA4-mutated cases, whereas the corresponding low-grade endometrioid component showed retained SMARCA4 expression. An expanded survey of other members of the SWI/SNF complex showed SMARCB1 loss in the undifferentiated component of two SMARCA4-intact tumors, and all SMARCA4- or SMARCB1-deficient tumors showed concomitant loss of expression of SMARCA2. We subsequently examined the expression of SMARCA2, SMARCA4, and SMARCB1 in an additional set of 22 centrally reviewed dedifferentiated carcinomas and 31 grade 3 endometrioid carcinomas. Combining the results from the index and the expansion set, 15 of 30 (50%) of the dedifferentiated carcinomas examined showed either concurrent SMARCA4 and SMARCA2 loss (37%) or concurrent SMARCB1 and SMARCA2 loss (13%) in the undifferentiated component. The loss of SMARCA4 or SMARCB1 was mutually exclusive. All 31 grade 3 endometrioid carcinomas showed intact expression of these core SWI/SNF proteins. The majority (73%) of the SMARCA4/SMARCA2-deficient and half of SMARCB1/SMARCA2-deficient undifferentiated component developed in a mismatch repair-deficient molecular context. The observed spatial association between SWI/SNF protein loss and histologic dedifferentiation suggests that inactivation of these core SWI/SNF proteins may contribute to the development of dedifferentiated endometrial carcinoma.
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14
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Erkina TY, Erkine A. ASF1 and the SWI/SNF complex interact functionally during nucleosome displacement, while FACT is required for nucleosome reassembly at yeast heat shock gene promoters during sustained stress. Cell Stress Chaperones 2015; 20:355-69. [PMID: 25416387 PMCID: PMC4326380 DOI: 10.1007/s12192-014-0556-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 10/14/2014] [Accepted: 11/10/2014] [Indexed: 12/22/2022] Open
Abstract
Histone chaperones are an integral part of the transcription regulatory machinery. We investigated the involvement of histone chaperones and their functional interactions with ATP-dependent chromatin remodeling complexes in the regulation of yeast heat shock genes. Strong functional interaction between the histone chaperone ASF1 and the ATP-dependent chromatin remodeling complex SWI/SNF is exhibited in synergistic diminishment of nucleosome displacement during heat shock in the ΔASF1/ΔSNF2 strain in comparison to individual ASF1 or SNF2 inactivation. A similar but less pronounced effect was observed for ISW1/ASF1 inactivation but not for ASF1/STH1 (RSC complex) combinatorial inactivation. The depletion of Spt16, which is a major subunit of the FACT histone chaperone complex, leads to a severe growth defect phenotype associated with unusual thermotolerance. The acquired thermotolerance in the Spt16-depleted strain is associated with a defect in the reassembly of nucleosomes at the promoters of heat shock genes during sustained heat stress, leading to increased recruitment of the transcriptional activator HSF and RNA polymerase II. The defect in nucleosome assembly associated with Spt16 depletion also leads to an increased tolerance to stress due to an increased concentration of NaCl.
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Affiliation(s)
- Tamara Y. Erkina
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Butler University, Indianapolis, IN 46208 USA
| | - Alexandre Erkine
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Butler University, Indianapolis, IN 46208 USA
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15
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Kahali B, Yu J, Marquez SB, Thompson KW, Liang SY, Lu L, Reisman D. The silencing of the SWI/SNF subunit and anticancer gene BRM in Rhabdoid tumors. Oncotarget 2014; 5:3316-32. [PMID: 24913006 PMCID: PMC4102812 DOI: 10.18632/oncotarget.1945] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 05/03/2014] [Indexed: 02/05/2023] Open
Abstract
Rhabdoid sarcomas are highly malignant tumors that usually occur in young children. A key to the genesis of this tumor is the mutational loss of the BAF47 gene as well as the widespread epigenetic suppression of other key anticancer genes. The BRM gene is one such epigenetically silenced gene in Rhabdoid tumors. This gene codes for an ATPase catalytic subunit that shifts histones and opens the chromatin. We show that BRM is an epigenetically silenced gene in 10/11 Rhabdoid cell lines and in 70% of Rhabdoid tumors. Moreover, BRM can be induced by BAF47 re-expression and by Flavopiridol. By selective shRNAi knockdown of BRM, we show that BRM re-expression is necessary for growth inhibition by BAF47 re-expression or Flavopiridol application. Similar to lung cancer cell lines, we found that HDAC3, HDAC9, MEF2D and GATA3 controlled BRM silencing and that HDAC9 was overexpressed in Rhabdoid cancer cell lines. In primary BRM-deficient Rhabdoid tumors, HDAC9 was also found to be highly overexpressed. Two insertional BRM promoter polymorphisms contribute to BRM silencing, but only the -1321 polymorphism correlated with BRM silencing in Rhabdoid cell lines. To determine how these polymorphisms were tied to BRM silencing, we conducted ChIP assays and found that both HDAC9 and MEF2D bound to the BRM promoter at or near these polymorphic sites. Using BRM promoter swap experiments, we indirectly showed that both HDAC9 and MEF2D bound to these polymorphic sites. Together, these data show that the mechanism of BRM silencing contributes to the pathogenesis of Rhabdoid tumors and appears to be conserved among tumor types.
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Affiliation(s)
- Bhaskar Kahali
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Florida, USA
| | - Jinlong Yu
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Florida, USA
| | - Stefanie B. Marquez
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Florida, USA
| | - Kenneth. W. Thompson
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Florida, USA
| | - Shermi Y. Liang
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Florida, USA
| | - Li Lu
- Department of Pathology, University of Florida, Florida, USA
| | - David Reisman
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Florida, USA
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16
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Skibinski A, Breindel JL, Prat A, Galván P, Smith E, Rolfs A, Gupta PB, LaBaer J, Kuperwasser C. The Hippo transducer TAZ interacts with the SWI/SNF complex to regulate breast epithelial lineage commitment. Cell Rep 2014; 6:1059-1072. [PMID: 24613358 PMCID: PMC4011189 DOI: 10.1016/j.celrep.2014.02.038] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 02/20/2014] [Accepted: 02/25/2014] [Indexed: 12/18/2022] Open
Abstract
Lineage-committed cells of many tissues exhibit substantial plasticity in contexts such as wound healing and tumorigenesis, but the regulation of this process is not well understood. We identified the Hippo transducer WWTR1/TAZ in a screen of transcription factors that are able to prompt lineage switching of mammary epithelial cells. Forced expression of TAZ in luminal cells induces them to adopt basal characteristics, and depletion of TAZ in basal and/or myoepithelial cells leads to luminal differentiation. In human and mouse tissues, TAZ is active only in basal cells and is critical for basal cell maintenance during homeostasis. Accordingly, loss of TAZ affects mammary gland development, leading to an imbalance of luminal and basal populations as well as branching defects. Mechanistically, TAZ interacts with components of the SWI/SNF complex to modulate lineage-specific gene expression. Collectively, these findings uncover a new role for Hippo signaling in the determination of lineage identity through recruitment of chromatin-remodeling complexes.
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Affiliation(s)
- Adam Skibinski
- Department of Developmental, Chemical, and Molecular Biology, Tufts University, 145 Harrison Avenue, Boston, MA 02111, USA; Molecular Oncology Research Institute, Tufts Medical Center, 800 Washington Street, Boston, MA 02111, USA
| | - Jerrica L Breindel
- Department of Developmental, Chemical, and Molecular Biology, Tufts University, 145 Harrison Avenue, Boston, MA 02111, USA; Molecular Oncology Research Institute, Tufts Medical Center, 800 Washington Street, Boston, MA 02111, USA
| | - Aleix Prat
- Translational Genomics Group, Vall d'Hebron Institute of Oncology, Passeig de la Vall d'Hebron 119-129, Barcelona 08035, Spain
| | - Patricia Galván
- Translational Genomics Group, Vall d'Hebron Institute of Oncology, Passeig de la Vall d'Hebron 119-129, Barcelona 08035, Spain
| | - Elizabeth Smith
- Department of Developmental, Chemical, and Molecular Biology, Tufts University, 145 Harrison Avenue, Boston, MA 02111, USA
| | - Andreas Rolfs
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Piyush B Gupta
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
| | - Joshua LaBaer
- Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, 727 East Tyler Street, Tempe, AZ 85287, USA
| | - Charlotte Kuperwasser
- Department of Developmental, Chemical, and Molecular Biology, Tufts University, 145 Harrison Avenue, Boston, MA 02111, USA; Molecular Oncology Research Institute, Tufts Medical Center, 800 Washington Street, Boston, MA 02111, USA.
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17
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Wilson BG, Wang X, Shen X, McKenna ES, Lemieux ME, Cho YJ, Koellhoffer EC, Pomeroy SL, Orkin SH, Roberts CWM. Epigenetic antagonism between polycomb and SWI/SNF complexes during oncogenic transformation. Cancer Cell 2010; 18:316-28. [PMID: 20951942 PMCID: PMC2957473 DOI: 10.1016/j.ccr.2010.09.006] [Citation(s) in RCA: 465] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 06/03/2010] [Accepted: 08/17/2010] [Indexed: 11/27/2022]
Abstract
Epigenetic alterations have been increasingly implicated in oncogenesis. Analysis of Drosophila mutants suggests that Polycomb and SWI/SNF complexes can serve antagonistic developmental roles. However, the relevance of this relationship to human disease is unclear. Here, we have investigated functional relationships between these epigenetic regulators in oncogenic transformation. Mechanistically, we show that loss of the SNF5 tumor suppressor leads to elevated expression of the Polycomb gene EZH2 and that Polycomb targets are broadly H3K27-trimethylated and repressed in SNF5-deficient fibroblasts and cancers. Further, we show antagonism between SNF5 and EZH2 in the regulation of stem cell-associated programs and that Snf5 loss activates those programs. Finally, using conditional mouse models, we show that inactivation of Ezh2 blocks tumor formation driven by Snf5 loss.
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MESH Headings
- Animals
- Cell Line, Tumor
- Cell Lineage
- Cell Proliferation
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/pathology
- Chromosomal Proteins, Non-Histone/deficiency
- Chromosomal Proteins, Non-Histone/genetics
- Chromosomal Proteins, Non-Histone/metabolism
- Cyclin-Dependent Kinase Inhibitor p16/metabolism
- Embryo, Mammalian/cytology
- Enhancer of Zeste Homolog 2 Protein
- Epigenesis, Genetic
- Fibroblasts/metabolism
- Gene Silencing
- Histone-Lysine N-Methyltransferase/genetics
- Histone-Lysine N-Methyltransferase/metabolism
- Histones/metabolism
- Humans
- Lysine/metabolism
- Methylation
- Mice
- Models, Genetic
- Polycomb Repressive Complex 2
- Polycomb-Group Proteins
- Repressor Proteins/metabolism
- SMARCB1 Protein
- Stem Cells/metabolism
- T-Lymphocytes/cytology
- T-Lymphocytes/metabolism
- Transcription, Genetic
- Up-Regulation/genetics
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Affiliation(s)
- Boris G. Wilson
- Department of Pediatric Oncology, Dana-Farber Cancer Institute; Division of Hematology/Oncology, Children's Hospital Boston, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Xi Wang
- Department of Pediatric Oncology, Dana-Farber Cancer Institute; Division of Hematology/Oncology, Children's Hospital Boston, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Xiaohua Shen
- Department of Pediatric Oncology, Dana-Farber Cancer Institute; Division of Hematology/Oncology, Children's Hospital Boston, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Elizabeth S. McKenna
- Department of Pediatric Oncology, Dana-Farber Cancer Institute; Division of Hematology/Oncology, Children's Hospital Boston, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Madeleine E. Lemieux
- Department of Pediatric Oncology, Dana-Farber Cancer Institute; Division of Hematology/Oncology, Children's Hospital Boston, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Yoon-Jae Cho
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115
| | - Edward C. Koellhoffer
- Department of Pediatric Oncology, Dana-Farber Cancer Institute; Division of Hematology/Oncology, Children's Hospital Boston, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Scott L. Pomeroy
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115
| | - Stuart H. Orkin
- Department of Pediatric Oncology, Dana-Farber Cancer Institute; Division of Hematology/Oncology, Children's Hospital Boston, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
- Howard Hughes Medical Institute, Boston, MA, 02115, USA
- Harvard Stem Cell Institute, Boston, MA, 02115, USA
| | - Charles W. M. Roberts
- Department of Pediatric Oncology, Dana-Farber Cancer Institute; Division of Hematology/Oncology, Children's Hospital Boston, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
- Requests for reprints: Charles W. M. Roberts, Dana-Farber Cancer Institute, Mayer 657, 44 Binney Street, Boston MA 02115, USA, Tel: 617-632-6497; FAX: 617-582-8096;
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18
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Abstract
The nuclear actin-related proteins (ARPs) share overall structure and low-level sequence homology with conventional actin. They are indispensable subunits of macromolecular machines that control chromatin remodeling and modification leading to dynamic changes in DNA structure, transcription, and DNA repair. Cellular, genetic, and biochemical studies suggest that the nuclear ARPs are essential to the epigenetic control of the cell cycle and cell proliferation in all eukaryotes, while in plants and animals they also exert epigenetic controls over most stages of multicellular development including organ initiation, the switch to reproductive development, and senescence and programmed cell death. A theme emerging from plants and animals is that in addition to their role in controlling the general compaction of DNA and gene silencing, isoforms of nuclear ARP-containing chromatin complexes have evolved to exert dynamic epigenetic control over gene expression and different phases of multicellular development. Herein, we explore this theme by examining nuclear ARP phylogeny, activities of ARP-containing chromatin remodeling complexes that lead to epigenetic control, expanding developmental roles assigned to several animal and plant ARP-containing complexes, the evidence that thousands of ARP complex isoforms may have evolved in concert with multicellular development, and ARPs in human disease.
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Affiliation(s)
- Richard B Meagher
- Department of Genetics, Davison Life Sciences Building, University of Georgia, Athens, GA 30602, USA
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19
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Yan Z, Wang Z, Sharova L, Sharov AA, Ling C, Piao Y, Aiba K, Matoba R, Wang W, Ko MS. BAF250B-associated SWI/SNF chromatin-remodeling complex is required to maintain undifferentiated mouse embryonic stem cells. Stem Cells 2008; 26:1155-65. [PMID: 18323406 PMCID: PMC2409195 DOI: 10.1634/stemcells.2007-0846] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Whether SWI/SNF chromatin remodeling complexes play roles in embryonic stem (ES) cells remains unknown. Here we show that SWI/SNF complexes are present in mouse ES cells, and their composition is dynamically regulated upon induction of ES cell differentiation. For example, the SWI/SNF purified from undifferentiated ES cells contains a high level of BAF155 and a low level of BAF170 (both of which are homologs of yeast SWI3 protein), whereas that from differentiated cells contains nearly equal amounts of both. Moreover, the levels of BAF250A and BAF250B decrease during the differentiation of ES cells, whereas that of BRM increases. The altered expression of SWI/SNF components hinted that these complexes could play roles in ES cell maintenance or differentiation. We therefore generated ES cells with biallelic inactivation of BAF250B and found that these cells display a reduced proliferation rate and an abnormal cell cycle. Importantly, these cells are deficient in the self-renewal capacity of undifferentiated ES cells and exhibit certain phenotypes of differentiated cells, including reduced expression of several pluripotency-related genes and increased expression of some differentiation-related genes. These data suggest that the BAF250B-associated SWI/SNF is essential for mouse ES cells to maintain their normal proliferation and pluripotency. The work presented here underscores the importance of SWI/SNF chromatin remodeling complexes in pluripotent stem cells.
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Affiliation(s)
- Zhijiang Yan
- Genome Instability and Chromatin-Remodeling Section, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - Zhong Wang
- Cardiovascular Research Center, Massachusetts General Hospital, Richard B. Simches Research Center, Harvard Medical School, Boston, MA 02114
| | - Lioudmila Sharova
- Developmental Genomics and Aging Section, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - Alexei A. Sharov
- Developmental Genomics and Aging Section, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - Chen Ling
- Genome Instability and Chromatin-Remodeling Section, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - Yulan Piao
- Developmental Genomics and Aging Section, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - Kazuhiro Aiba
- Developmental Genomics and Aging Section, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - Ryo Matoba
- Developmental Genomics and Aging Section, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - Weidong Wang
- Genome Instability and Chromatin-Remodeling Section, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
| | - Minoru S.H. Ko
- Developmental Genomics and Aging Section, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224
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20
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Abstract
Eukaryotic genetic information is stored within the association of DNA and histone proteins resulting in a dynamic polymer called chromatin. The fundamental structural unit of chromatin is the nucleosome which consists of approximately 146 bp of DNA wrapped around an octamer of histones containing two copies each of four core histones, H2A, H2B, H3 and H4. It is this DNA/protein fiber that transcription factors and other agents of chromatin metabolism must access and regulate. We have developed model systems to study the mechanisms by which steroid receptors control physiological activities by regulating gene expression within a higher order chromatin organization. Our studies have focused on the glucocorticoid receptor and its ability to remodel chromatin which is mediated by the BRG1 complex. Using novel cell systems, we demonstrate that GR-mediated transactivation from chromatin templates requires BRG1 remodeling activity and that other ATP-dependent remodeling proteins cannot substitute for this activity.
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Affiliation(s)
| | - Trevor K. Archer
- Corresponding author. Tel.: +1 919 316 4565; fax: +1 919 316 4566. (T.K. Archer)
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21
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Da G, Lenkart J, Zhao K, Shiekhattar R, Cairns BR, Marmorstein R. Structure and function of the SWIRM domain, a conserved protein module found in chromatin regulatory complexes. Proc Natl Acad Sci U S A 2006; 103:2057-62. [PMID: 16461455 PMCID: PMC1413740 DOI: 10.1073/pnas.0510949103] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Indexed: 11/18/2022] Open
Abstract
The SWIRM domain is a module found in the Swi3 and Rsc8 subunits of SWI/SNF-family chromatin remodeling complexes, and the Ada2 and BHC110/LSD1 subunits of chromatin modification complexes. Here we report the high-resolution crystal structure of the SWIRM domain from Swi3 and characterize the in vitro and in vivo function of the SWIRM domains from Saccharomyces cerevisiae Swi3 and Rsc8. The Swi3 SWIRM forms a four-helix bundle containing a pseudo 2-fold axis and a helix-turn-helix motif commonly found in DNA-binding proteins. We show that the Swi3 SWIRM binds free DNA and mononucleosomes with high and comparable affinity and that a subset of Swi3 substitution mutants that display growth defects in vivo also show impaired DNA-binding activity in vitro, consistent with a nucleosome targeting function of this domain. Genetic and biochemical studies also reveal that the Rsc8 and Swi3 SWIRM domains are essential for the proper assembly and in vivo functions of their respective complexes. Together, these studies identify the SWIRM domain as an essential multifunctional module for the regulation of gene expression.
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Affiliation(s)
- Guoping Da
- *The Wistar Institute and
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104; and
| | - Jeffrey Lenkart
- Howard Hughes Medical Institute and Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT 84112
| | | | | | - Bradley R. Cairns
- Howard Hughes Medical Institute and Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT 84112
| | - Ronen Marmorstein
- *The Wistar Institute and
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104; and
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22
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Bultman SJ, Gebuhr TC, Magnuson T. A Brg1 mutation that uncouples ATPase activity from chromatin remodeling reveals an essential role for SWI/SNF-related complexes in beta-globin expression and erythroid development. Genes Dev 2005; 19:2849-61. [PMID: 16287714 PMCID: PMC1315392 DOI: 10.1101/gad.1364105] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Accepted: 09/29/2005] [Indexed: 11/25/2022]
Abstract
The Brg1 catalytic subunit of SWI/SNF-related complexes has been implicated in many developmental and physiological processes, but null homozygotes die as blastocysts prior to implantation. To circumvent this early embryonic lethality, we performed an ENU mutagenesis screen and generated a Brg1 hypomorph mutation in the ATPase domain. The mutant Brg1 protein is stable, assembles into SWI/SNF-related complexes, and exhibits normal ATPase activity but is unable to establish DNase I hypersensitivity sites characteristic of open chromatin. Mutant embryos develop normally until midgestation but then exhibit a distinct block in the development of the erythroid lineage, leading to anemia and death. The mutant Brg1 protein is recruited to the beta-globin locus, but chromatin remodeling and transcription are perturbed. Histone acetylation and DNA methylation are also affected. To our knowledge, Brg1 is the first chromatin-modifying factor shown to be required for beta-globin regulation and erythropoiesis in vivo. Not only does this mutation establish a role for Brg1 during organogenesis, it also demonstrates that ATPase activity can be uncoupled from chromatin remodeling.
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Affiliation(s)
- Scott J Bultman
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599-7264, USA.
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Xue Y, Gibbons R, Yan Z, Yang D, McDowell TL, Sechi S, Qin J, Zhou S, Higgs D, Wang W. The ATRX syndrome protein forms a chromatin-remodeling complex with Daxx and localizes in promyelocytic leukemia nuclear bodies. Proc Natl Acad Sci U S A 2003; 100:10635-40. [PMID: 12953102 PMCID: PMC196856 DOI: 10.1073/pnas.1937626100] [Citation(s) in RCA: 280] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
ATRX syndrome is characterized by X-linked mental retardation associated with alpha-thalassemia. The gene mutated in this disease, ATRX, encodes a plant homeodomain-like finger and a SWI2/SNF2-like ATPase motif, both of which are often found in chromatin-remodeling enzymes, but ATRX has not been characterized biochemically. By immunoprecipitation from HeLa extract, we found that ATRX is in a complex with transcription cofactor Daxx. The following evidence supports that ATRX and Daxx are components of an ATP-dependent chromatin-remodeling complex: (i) Daxx and ATRX can be coimmunoisolated by antibodies specific for each protein; (ii) a proportion of Daxx cofractionates with ATRX as a complex of 1 MDa by gel-filtration analysis; (iii) in extract from cells of a patient with ATRX syndrome, the level of the Daxx-ATRX complex is correspondingly reduced; (iv) a proportion of ATRX and Daxx colocalize in promyelocytic leukemia nuclear bodies, with which Daxx had previously been located; and (v) the ATRX complex displays ATP-dependent activities that resemble those of other chromatin-remodeling complexes, including triple-helix DNA displacement and alteration of mononucleosome disruption patterns. But unlike the previously described SWI/SNF or NURD complexes, the ATRX complex does not randomize DNA phasing of the mononucleosomes, suggesting that it may remodel chromatin differently. Taken together, the results suggest that ATRX functions in conjunction with Daxx in a novel chromatin-remodeling complex. The defects in ATRX syndrome may result from inappropriate expression of genes controlled by this complex.
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Affiliation(s)
- Yutong Xue
- Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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Corey LL, Weirich CS, Benjamin IJ, Kingston RE. Localized recruitment of a chromatin-remodeling activity by an activator in vivo drives transcriptional elongation. Genes Dev 2003; 17:1392-401. [PMID: 12782657 PMCID: PMC196071 DOI: 10.1101/gad.1071803] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To understand the role of chromatin-remodeling activities in transcription, it is necessary to understand how they interact with transcriptional activators in vivo to regulate the different steps of transcription. Human heat shock factor 1 (HSF1) stimulates both transcriptional initiation and elongation. We replaced mouse HSF1 in fibroblasts with wild-type and mutant human HSF1 constructs and characterized regulation of an endogenous mouse hsp70 gene. A mutation that diminished transcriptional initiation led to twofold reductions in hsp70 mRNA induction and recruitment of a SWI/SNF remodeling complex. In contrast, a mutation that diminished transcriptional elongation abolished induction of full-length mRNA, SWI/SNF recruitment, and chromatin remodeling, but minimally impaired initiation from the hsp70 promoter. Another remodeling factor, SNF2h, is constitutively present at the promoter irrespective of the genotype of HSF1. These data suggest that localized recruitment of SWI/SNF drives a specialized remodeling reaction necessary for the production of full-length hsp70 mRNA.
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Affiliation(s)
- Laura L Corey
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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25
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Abstract
Gene expression requires the recruitment of chromatin remodeling activities and general transcription factors (GTFs) to promoters. Whereas the role of activators in recruiting chromatin remodeling activities has been clearly demonstrated, the contributions of the transcription machinery have not been firmly established. Here we demonstrate that the remodeling of the RNR3 promoter requires a number of GTFs, mediator and RNA polymerase II. We also show that remodeling is dependent upon the SWI/SNF complex, and that TFIID and RNA polymerase II are required for its recruitment to the promoter. In contrast, Gcn5p-dependent histone acetylation occurs independently of TFIID and RNA polymerase II function, and we provide evidence that acetylation increases the extent of nucleosome remodeling, but is not required for SWI/SNF recruitment. Thus, the general transcription machinery can contribute to nucleosome remodeling by mediating the association of SWI/SNF with promoters, thereby revealing a novel pathway for the recruitment of chromatin remodeling activities.
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Affiliation(s)
- Vishva Mitra Sharma
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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26
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Abstract
Many studies have established that the Swi/Snf family of chromatin-remodeling complexes activate transcription. Recent reports have suggested the possibility that these complexes can also repress transcription. We now present chromatin immunoprecipitation evidence that the Swi/Snf complex of Saccharomyces cerevisiae directly represses transcription of the SER3 gene. Consistent with its role in nucleosome remodeling, Swi/Snf controls the chromatin structure of the SER3 promoter. However, in striking contrast to activation by Swi/Snf, which requires most Swi/Snf subunits, repression by Swi/Snf at SER3 is dependent primarily on one Swi/Snf component, Snf2. These results show distinct differences in the requirements for Swi/Snf components in transcriptional activation and repression.
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Affiliation(s)
- Joseph A Martens
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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27
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Abstract
Chromatin-remodeling complexes couple ATP hydrolysis to alterations in histone-DNA interactions and nucleosome mobility, allowing transcription factors access to chromatin. Here, we use triple-helix strand-displacement assays, DNA length-dependent ATPase assays, and DNA-minicircle ATPase assays to establish that RSC, as well as its isolated ATPase subunit Sth1, are DNA translocases. RSC/Sth1 ATPase activity is stimulated by single-stranded DNA, suggesting that Sth1 tracks along one strand of the DNA duplex. Each RSC complex appears to contain a single molecule of Sth1, and isolated Sth1 is capable of nucleosome remodeling. We propose that the remodeling enzyme remains in a fixed position on the octamer and translocates a segment of DNA (with accompanying DNA twist), which breaks histone-DNA contacts and propagates as a wave of DNA around the octamer. The demonstration of DNA translocation presented here provides a mechanistic basis for this DNA wave. To test the relative contribution of twist to remodeling, we use nucleosomes containing nicks in precise locations to uncouple twist and translocation. Nucleosomes bearing nicks are remodeled less efficiently than intact nucleosomes. These results suggest that RSC and Sth1 are DNA translocases that use both DNA translocation and twist to remodel nucleosomes efficiently.
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Affiliation(s)
- Anjanabha Saha
- Howard Hughes Medical Institute and the Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
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Pedersen TA, Kowenz-Leutz E, Leutz A, Nerlov C. Cooperation between C/EBPalpha TBP/TFIIB and SWI/SNF recruiting domains is required for adipocyte differentiation. Genes Dev 2001; 15:3208-16. [PMID: 11731483 PMCID: PMC312836 DOI: 10.1101/gad.209901] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Chromatin remodeling is an important step in promoter activation during cellular lineage commitment and differentiation. We show that the ability of the C/EBPalpha transcription factor to direct adipocyte differentiation of uncommitted fibroblast precursors and to activate SWI/SNF-dependent myeloid-specific genes depends on a domain, C/EBPalpha transactivation element III (TE-III), that binds the SWI/SNF chromatin remodeling complex. TE-III collaborates with C/EBPalpha TBP/TFIIB interaction motifs during induction of adipogenesis and adipocyte-specific gene expression. These results indicate that C/EBPalpha acts as a lineage-instructive transcription factor through SWI/SNF-dependent modification of the chromatin structure of lineage-specific genes, followed by direct promoter activation via recruitment of the basal transcription-initiation complex, and provide a mechanism by which C/EBPalpha can mediate differentiation along multiple cellular lineages.
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Affiliation(s)
- T A Pedersen
- Laboratory of Gene Therapy Research, Copenhagen University Hospital, 2100 Copenhagen, Denmark
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29
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Abstract
Proteins that contain a motif called a bromodomain are implicated in both transcriptional activation and repression. The bromodomain of p/CAF, the only solution structure of a bromodomain that has been solved to date, reveals that the motif binds N-acetyl-lysine groups, presumably to anchor enzymatic functions to histones and by extension to chromatin. The enzymatic activities can either be encoded within the same polypeptide as the bromodomain motif, or associated with a multiprotein complex. Thus, a wide variety of chromatin-directed functions, including but not limited to phosphorylation, acetylation, methylation, transcriptional co-activation or recruitment, characterize the complexes that contain bromodomain motifs. Their versatility and ubiquity ensures diverse, rapid and flexible transcriptional responses.
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Affiliation(s)
- G V Denis
- Cancer Research Center, Boston University School of Medicine, Room L910, 80 East Concord Street, Boston, MA, USA 02118, USA.
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Abstract
The Wingless signaling pathway directs many developmental processes in Drosophila by regulating the expression of specific downstream target genes. We report here that the product of the trithorax group gene osa is required to repress such genes in the absence of the Wingless signal. The Wingless-regulated genes nubbin, Distal-less, and decapentaplegic and a minimal enhancer from the Ultrabithorax gene are misexpressed in osa mutants and repressed by ectopic Osa. Osa-mediated repression occurs downstream of the up-regulation of Armadillo but is sensitive both to the relative levels of activating Armadillo/Pangolin and repressing Groucho/Pangolin complexes present and to the responsiveness of the promoter to Wingless. Osa functions as a component of the Brahma chromatin-remodeling complex; other components of this complex are likewise required to repress Wingless target genes. These results suggest that altering the conformation of chromatin is an important mechanism by which Wingless signaling activates gene expression.
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Affiliation(s)
- R T Collins
- Skirball Institute of Biomolecular Medicine and Department of Cell Biology, New York University School of Medicine, New York, New York 10016, USA
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Abstract
The SWI/SNF family of chromatin-remodeling complexes plays a key role in facilitating the binding of specific transcription factors to nucleosomal DNA in diverse organisms from yeast to man. Yet the process by which SWI/SNF and other chromatin-remodeling complexes activate specific subsets of genes is poorly understood. We show that mammalian SWI/SNF regulates transcription from chromatin-assembled genes in a factor-specific manner in vitro. The DNA-binding domains (DBDs) of several zinc finger proteins, including EKLF, interact directly with SWI/SNF to generate DNase I hypersensitivity within the chromatin-assembled beta-globin promoter. Interestingly, we find that two SWI/SNF subunits (BRG1 and BAF155) are necessary and sufficient for targeted chromatin remodeling and transcriptional activation by EKLF in vitro. Remodeling is achieved with only the BRG1-BAF155 minimal complex and the EKLF zinc finger DBD, whereas transcription requires, in addition, an activation domain. In contrast, the BRG1-BAF155 complex does not interact or function with two unrelated transcription factors, TFE3 and NF-kappaB. We conclude that specific domains of certain transcription factors differentially target SWI/SNF complexes to chromatin in a gene-selective manner and that individual SWI/SNF subunits play unique roles in transcription factor-directed nucleosome remodeling.
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Affiliation(s)
- S Kadam
- Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
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Kal AJ, Mahmoudi T, Zak NB, Verrijzer CP. The Drosophila brahma complex is an essential coactivator for the trithorax group protein zeste. Genes Dev 2000; 14:1058-71. [PMID: 10809665 PMCID: PMC316570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The trithorax group (trxG) of activators and Polycomb group (PcG) of repressors are believed to control the expression of several key developmental regulators by changing the structure of chromatin. Here, we have sought to dissect the requirements for transcriptional activation by the Drosophila trxG protein Zeste, a DNA-binding activator of homeotic genes. Reconstituted transcription reactions established that the Brahma (BRM) chromatin-remodeling complex is essential for Zeste-directed activation on nucleosomal templates. Because it is not required for Zeste to bind to chromatin, the BRM complex appears to act after promoter binding by the activator. Purification of the Drosophila BRM complex revealed a number of novel subunits. We found that Zeste tethers the BRM complex via direct binding to specific subunits, including trxG proteins Moira (MOR) and OSA. The leucine zipper of Zeste mediates binding to MOR. Interestingly, although the Imitation Switch (ISWI) remodelers are potent nucleosome spacing factors, they are dispensable for transcriptional activation by Zeste. Thus, there is a distinction between general chromatin restructuring and transcriptional coactivation by remodelers. These results establish that different chromatin remodeling factors display distinct functional properties and provide novel insights into the mechanism of their targeting.
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Affiliation(s)
- A J Kal
- Department of Molecular and Cell Biology, MGC, Centre for Biomedical Genetics, Leiden University Medical Centre, 2300 RA Leiden, The Netherlands
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