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Thang NX, Han DW, Park C, Lee H, La H, Yoo S, Lee H, Uhm SJ, Song H, Do JT, Park KS, Choi Y, Hong K. INO80 function is required for mouse mammary gland development, but mutation alone may be insufficient for breast cancer. Front Cell Dev Biol 2023; 11:1253274. [PMID: 38020889 PMCID: PMC10646318 DOI: 10.3389/fcell.2023.1253274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
The aberrant function of ATP-dependent chromatin remodeler INO80 has been implicated in multiple types of cancers by altering chromatin architecture and gene expression; however, the underlying mechanism of the functional involvement of INO80 mutation in cancer etiology, especially in breast cancer, remains unclear. In the present study, we have performed a weighted gene co-expression network analysis (WCGNA) to investigate links between INO80 expression and breast cancer sub-classification and progression. Our analysis revealed that INO80 repression is associated with differential responsiveness of estrogen receptors (ERs) depending upon breast cancer subtype, ER networks, and increased risk of breast carcinogenesis. To determine whether INO80 loss induces breast tumors, a conditional INO80-knockout (INO80 cKO) mouse model was generated using the Cre-loxP system. Phenotypic characterization revealed that INO80 cKO led to reduced branching and length of the mammary ducts at all stages. However, the INO80 cKO mouse model had unaltered lumen morphology and failed to spontaneously induce tumorigenesis in mammary gland tissue. Therefore, our study suggests that the aberrant function of INO80 is potentially associated with breast cancer by modulating gene expression. INO80 mutation alone is insufficient for breast tumorigenesis.
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Affiliation(s)
- Nguyen Xuan Thang
- Department of Stem Cell and Regenerative Biotechnology, Institute of Advanced Regenerative Science, Konkuk University, Seoul, Republic of Korea
| | - Dong Wook Han
- Guangdong Provincial Key Laboratory of Large Animal Models for Biomedicine, Wuyi University, Jiangmen, China
| | - Chanhyeok Park
- Department of Stem Cell and Regenerative Biotechnology, Institute of Advanced Regenerative Science, Konkuk University, Seoul, Republic of Korea
| | - Hyeonji Lee
- Department of Stem Cell and Regenerative Biotechnology, Institute of Advanced Regenerative Science, Konkuk University, Seoul, Republic of Korea
| | - Hyeonwoo La
- Department of Stem Cell and Regenerative Biotechnology, Institute of Advanced Regenerative Science, Konkuk University, Seoul, Republic of Korea
| | - Seonho Yoo
- Department of Stem Cell and Regenerative Biotechnology, Institute of Advanced Regenerative Science, Konkuk University, Seoul, Republic of Korea
| | - Heeji Lee
- Department of Stem Cell and Regenerative Biotechnology, Institute of Advanced Regenerative Science, Konkuk University, Seoul, Republic of Korea
| | - Sang Jun Uhm
- Department of Animal Science, Sangji University, Wonju, Republic of Korea
| | - Hyuk Song
- Department of Stem Cell and Regenerative Biotechnology, Institute of Advanced Regenerative Science, Konkuk University, Seoul, Republic of Korea
| | - Jeong Tae Do
- Department of Stem Cell and Regenerative Biotechnology, Institute of Advanced Regenerative Science, Konkuk University, Seoul, Republic of Korea
| | - Kyoung Sik Park
- Department of Surgery, School of Medicine, Konkuk University, Seoul, Republic of Korea
| | - Youngsok Choi
- Department of Stem Cell and Regenerative Biotechnology, Institute of Advanced Regenerative Science, Konkuk University, Seoul, Republic of Korea
| | - Kwonho Hong
- Department of Stem Cell and Regenerative Biotechnology, Institute of Advanced Regenerative Science, Konkuk University, Seoul, Republic of Korea
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Saraç H, Morova T, Pires E, McCullagh J, Kaplan A, Cingöz A, Bagci-Onder T, Önder T, Kawamura A, Lack NA. Systematic characterization of chromatin modifying enzymes identifies KDM3B as a critical regulator in castration resistant prostate cancer. Oncogene 2020; 39:2187-2201. [PMID: 31822799 PMCID: PMC7056651 DOI: 10.1038/s41388-019-1116-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 11/05/2019] [Accepted: 11/11/2019] [Indexed: 12/28/2022]
Abstract
Androgen deprivation therapy (ADT) is the standard care for prostate cancer (PCa) patients who fail surgery or radiotherapy. While initially effective, the cancer almost always recurs as a more aggressive castration resistant prostate cancer (CRPC). Previous studies have demonstrated that chromatin modifying enzymes can play a critical role in the conversion to CRPC. However, only a handful of these potential pharmacological targets have been tested. Therefore, in this study, we conducted a focused shRNA screen of chromatin modifying enzymes previously shown to be involved in cellular differentiation. We found that altering the balance between histone methylation and demethylation impacted growth and proliferation. Of all genes tested, KDM3B, a histone H3K9 demethylase, was found to have the most antiproliferative effect. These results were phenocopied with a KDM3B CRISPR/Cas9 knockout. When tested in several PCa cell lines, the decrease in proliferation was remarkably specific to androgen-independent cells. Genetic rescue experiments showed that only the enzymatically active KDM3B could recover the phenotype. Surprisingly, despite the decreased proliferation of androgen-independent cell no alterations in the cell cycle distribution were observed following KDM3B knockdown. Whole transcriptome analyses revealed changes in the gene expression profile following loss of KDM3B, including downregulation of metabolic enzymes such as ARG2 and RDH11. Metabolomic analysis of KDM3B knockout showed a decrease in several critical amino acids. Overall, our work reveals, for the first time, the specificity and the dependence of KDM3B in CRPC proliferation.
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Affiliation(s)
- Hilal Saraç
- School of Medicine, Koç University, Istanbul, 34450, Turkey
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
- Radcliffe Department of Medicine, Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Tunç Morova
- School of Medicine, Koç University, Istanbul, 34450, Turkey
- Vancouver Prostate Centre, University of British Columbia, Vancouver, V6H 3Z6, Canada
| | - Elisabete Pires
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - James McCullagh
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Anıl Kaplan
- School of Medicine, Koç University, Istanbul, 34450, Turkey
| | - Ahmet Cingöz
- School of Medicine, Koç University, Istanbul, 34450, Turkey
| | | | - Tamer Önder
- School of Medicine, Koç University, Istanbul, 34450, Turkey
| | - Akane Kawamura
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
- Radcliffe Department of Medicine, Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Nathan A Lack
- School of Medicine, Koç University, Istanbul, 34450, Turkey.
- Vancouver Prostate Centre, University of British Columbia, Vancouver, V6H 3Z6, Canada.
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3
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Jancewicz I, Siedlecki JA, Sarnowski TJ, Sarnowska E. BRM: the core ATPase subunit of SWI/SNF chromatin-remodelling complex-a tumour suppressor or tumour-promoting factor? Epigenetics Chromatin 2019; 12:68. [PMID: 31722744 PMCID: PMC6852734 DOI: 10.1186/s13072-019-0315-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 10/31/2019] [Indexed: 02/07/2023] Open
Abstract
BRM (BRAHMA) is a core, SWI2/SNF2-type ATPase subunit of SWI/SNF chromatin-remodelling complex (CRC) involved in various important regulatory processes including development. Mutations in SMARCA2, a BRM-encoding gene as well as overexpression or epigenetic silencing were found in various human diseases including cancer. Missense mutations in SMARCA2 gene were recently connected with occurrence of Nicolaides-Baraitser genetics syndrome. By contrast, SMARCA2 duplication rather than mutations is characteristic for Coffin-Siris syndrome. It is believed that BRM usually acts as a tumour suppressor or a tumour susceptibility gene. However, other studies provided evidence that BRM function may differ depending on the cancer type and the disease stage, where BRM may play a role in the disease progression. The existence of alternative splicing forms of SMARCA2 gene, leading to appearance of truncated functional, loss of function or gain-of-function forms of BRM protein suggest a far more complicated mode of BRM-containing SWI/SNF CRCs actions. Therefore, the summary of recent knowledge regarding BRM alteration in various types of cancer and highlighting of differences and commonalities between BRM and BRG1, another SWI2/SNF2 type ATPase, will lead to better understanding of SWI/SNF CRCs function in cancer development/progression. BRM has been recently proposed as an attractive target for various anticancer therapies including the use of small molecule inhibitors, synthetic lethality induction or proteolysis-targeting chimera (PROTAC). However, such attempts have some limitations and may lead to severe side effects given the homology of BRM ATPase domain to other ATPases, as well as due to the tissue-specific appearance of BRM- and BRG1-containing SWI/SNF CRC classes. Thus, a better insight into BRM-containing SWI/SNF CRCs function in human tissues and cancers is clearly required to provide a solid basis for establishment of new safe anticancer therapies.
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Affiliation(s)
- Iga Jancewicz
- Department of Molecular and Translational Oncology, The Maria Sklodowska-Curie Institute-Oncology Center in Warsaw, Wawelska 15B, 02-034, Warsaw, Poland
| | - Janusz A Siedlecki
- Department of Molecular and Translational Oncology, The Maria Sklodowska-Curie Institute-Oncology Center in Warsaw, Wawelska 15B, 02-034, Warsaw, Poland
| | - Tomasz J Sarnowski
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland.
| | - Elzbieta Sarnowska
- Department of Molecular and Translational Oncology, The Maria Sklodowska-Curie Institute-Oncology Center in Warsaw, Wawelska 15B, 02-034, Warsaw, Poland.
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4
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Porter EG, Dhiman A, Chowdhury B, Carter BC, Lin H, Stewart JC, Kazemian M, Wendt MK, Dykhuizen EC. PBRM1 Regulates Stress Response in Epithelial Cells. iScience 2019; 15:196-210. [PMID: 31077944 PMCID: PMC6514269 DOI: 10.1016/j.isci.2019.04.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 03/10/2019] [Accepted: 04/19/2019] [Indexed: 12/16/2022] Open
Abstract
Polybromo1 (PBRM1) is a chromatin remodeler subunit highly mutated in cancer, particularly clear cell renal carcinoma. PBRM1 is a member of the SWI/SNF subcomplex, PBAF (PBRM1-Brg1/Brm-associated factors), and is characterized by six tandem bromodomains. Here we establish a role for PBRM1 in epithelial cell maintenance through the expression of genes involved in cell adhesion, metabolism, stress response, and apoptosis. In support of a general role for PBRM1 in stress response and apoptosis, we observe that loss of PBRM1 results in an increase in reactive oxygen species generation and a decrease in cellular viability under stress conditions. We find that loss of PBRM1 promotes cell growth under favorable conditions but is required for cell survival under conditions of cellular stress. PBRM1 facilitates the expression of stress response genes in epithelial cells Deletion of PBRM1 promotes growth under low-stress conditions PBRM1 restrains ROS generation and induces apoptosis under high-stress conditions Under H2O2 stress, PBRM1 cooperates with cJun and NRF2 to induce gene expression
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Affiliation(s)
- Elizabeth G Porter
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47906, USA
| | - Alisha Dhiman
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47906, USA
| | - Basudev Chowdhury
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47906, USA
| | - Benjamin C Carter
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47906, USA
| | - Hang Lin
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47906, USA
| | - Jane C Stewart
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47906, USA
| | - Majid Kazemian
- Department of Biochemistry, Purdue University, West Lafayette, IN 47906, USA
| | - Michael K Wendt
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47906, USA
| | - Emily C Dykhuizen
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47906, USA.
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5
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Zaidi SK, Fritz AJ, Tracy KM, Gordon JA, Tye CE, Boyd J, Van Wijnen AJ, Nickerson JA, Imbalzano AN, Lian JB, Stein JL, Stein GS. Nuclear organization mediates cancer-compromised genetic and epigenetic control. Adv Biol Regul 2018; 69:1-10. [PMID: 29759441 PMCID: PMC6102062 DOI: 10.1016/j.jbior.2018.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 04/13/2018] [Accepted: 05/02/2018] [Indexed: 12/19/2022]
Abstract
Nuclear organization is functionally linked to genetic and epigenetic regulation of gene expression for biological control and is modified in cancer. Nuclear organization supports cell growth and phenotypic properties of normal and cancer cells by facilitating physiologically responsive interactions of chromosomes, genes and regulatory complexes at dynamic three-dimensional microenvironments. We will review nuclear structure/function relationships that include: 1. Epigenetic bookmarking of genes by phenotypic transcription factors to control fidelity and plasticity of gene expression as cells enter and exit mitosis; 2. Contributions of chromatin remodeling to breast cancer nuclear morphology, metabolism and effectiveness of chemotherapy; 3. Relationships between fidelity of nuclear organization and metastasis of breast cancer to bone; 4. Dynamic modifications of higher-order inter- and intra-chromosomal interactions in breast cancer cells; 5. Coordinate control of cell growth and phenotype by tissue-specific transcription factors; 6. Oncofetal epigenetic control by bivalent histone modifications that are functionally related to sustaining the stem cell phenotype; and 7. Noncoding RNA-mediated regulation in the onset and progression of breast cancer. The discovery of components to nuclear organization that are functionally related to cancer and compromise gene expression have the potential for translation to innovative cancer diagnosis and targeted therapy.
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Affiliation(s)
- Sayyed K Zaidi
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States
| | - Andrew J Fritz
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States
| | - Kirsten M Tracy
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States
| | - Jonathan A Gordon
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States
| | - Coralee E Tye
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States
| | - Joseph Boyd
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States
| | - Andre J Van Wijnen
- Departments of Orthopedic Surgery, Biochemistry & Molecular Biology, Mayo Clinic, Rochester, MN, United States
| | - Jeffrey A Nickerson
- Department of Pediatrics, UMass Medical School, Worcester, MA, United States
| | - Antony N Imbalzano
- Graduate Program in Cell Biology and Department of Biochemistry and Molecular Pharmacology, UMass Medical School, Worcester, MA, United States
| | - Jane B Lian
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States
| | - Janet L Stein
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States.
| | - Gary S Stein
- Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States.
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6
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Wu Q, Madany P, Dobson JR, Schnabl JM, Sharma S, Smith TC, van Wijnen AJ, Stein JL, Lian JB, Stein GS, Muthuswami R, Imbalzano AN, Nickerson JA. The BRG1 chromatin remodeling enzyme links cancer cell metabolism and proliferation. Oncotarget 2018; 7:38270-38281. [PMID: 27223259 PMCID: PMC5122388 DOI: 10.18632/oncotarget.9505] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/01/2016] [Indexed: 12/20/2022] Open
Abstract
Cancer cells reprogram cellular metabolism to meet the demands of growth. Identification of the regulatory machinery that regulates cancer-specific metabolic changes may open new avenues for anti-cancer therapeutics. The epigenetic regulator BRG1 is a catalytic ATPase for some mammalian SWI/SNF chromatin remodeling enzymes. BRG1 is a well-characterized tumor suppressor in some human cancers, but is frequently overexpressed without mutation in other cancers, including breast cancer. Here we demonstrate that BRG1 upregulates de novo lipogenesis and that this is crucial for cancer cell proliferation. Knockdown of BRG1 attenuates lipid synthesis by impairing the transcription of enzymes catalyzing fatty acid and lipid synthesis. Remarkably, exogenous addition of palmitate, the key intermediate in fatty acid synthesis, rescued the cancer cell proliferation defect caused by BRG1 knockdown. Our work suggests that targeting BRG1 to reduce lipid metabolism and, thereby, to reduce proliferation, has promise for epigenetic therapy in triple negative breast cancer.
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Affiliation(s)
- Qiong Wu
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Pasil Madany
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Jason R Dobson
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Jake M Schnabl
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Soni Sharma
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, Delhi, India
| | - Tara C Smith
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Andre J van Wijnen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Janet L Stein
- Department of Biochemistry and Vermont Cancer Center for Basic and Translational Research, University of Vermont College of Medicine, Burlington, WA, USA
| | - Jane B Lian
- Department of Biochemistry and Vermont Cancer Center for Basic and Translational Research, University of Vermont College of Medicine, Burlington, WA, USA
| | - Gary S Stein
- Department of Biochemistry and Vermont Cancer Center for Basic and Translational Research, University of Vermont College of Medicine, Burlington, WA, USA
| | - Rohini Muthuswami
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, Delhi, India
| | - Anthony N Imbalzano
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Jeffrey A Nickerson
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
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7
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Wu Q, Sharma S, Cui H, LeBlanc SE, Zhang H, Muthuswami R, Nickerson JA, Imbalzano AN. Targeting the chromatin remodeling enzyme BRG1 increases the efficacy of chemotherapy drugs in breast cancer cells. Oncotarget 2017; 7:27158-75. [PMID: 27029062 PMCID: PMC5053639 DOI: 10.18632/oncotarget.8384] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 03/16/2016] [Indexed: 12/31/2022] Open
Abstract
Brahma related gene product 1 (BRG1) is an ATPase that drives the catalytic activity of a subset of the mammalian SWI/SNF chromatin remodeling enzymes. BRG1 is overexpressed in most human breast cancer tumors without evidence of mutation and is required for breast cancer cell proliferation. We demonstrate that knockdown of BRG1 sensitized triple negative breast cancer cells to chemotherapeutic drugs used to treat breast cancer. An inhibitor of the BRG1 bromodomain had no effect on breast cancer cell viability, but an inhibitory molecule that targets the BRG1 ATPase activity recapitulated the increased drug efficacy observed in the presence of BRG1 knockdown. We further demonstrate that inhibition of BRG1 ATPase activity blocks the induction of ABC transporter genes by these chemotherapeutic drugs and that BRG1 binds to ABC transporter gene promoters. This inhibition increased intracellular concentrations of the drugs, providing a likely mechanism for the increased chemosensitivity. Since ABC transporters and their induction by chemotherapy drugs are a major cause of chemoresistance and treatment failure, these results support the idea that targeting the enzymatic activity of BRG1 would be an effective adjuvant therapy for breast cancer.
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Affiliation(s)
- Qiong Wu
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Soni Sharma
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, Delhi, India
| | - Hang Cui
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA.,Abace Biotech Co Ltd., Yi Zhuang Biomedical Park, BDA, Beijing, China
| | - Scott E LeBlanc
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Hong Zhang
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Rohini Muthuswami
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, Delhi, India
| | - Jeffrey A Nickerson
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Anthony N Imbalzano
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
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8
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Brg1 inhibits E-cadherin expression in lung epithelial cells and disrupts epithelial integrity. J Mol Med (Berl) 2017; 95:1117-1126. [PMID: 28801844 DOI: 10.1007/s00109-017-1576-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 06/04/2017] [Accepted: 07/28/2017] [Indexed: 12/07/2022]
Abstract
Brahma-related gene-1 (Brg1), a key chromatin remodeling factor, is associated with cell proliferation and migration in kidney and heart cells, but few reports have examined its role in airway epithelial cell. Airway epithelial injury, which is involved in the entire pathological process of asthma, is an important cause of recurrent asthma. Here, we studied the function of Brg1 in an ovalbumin (OVA)-induced asthma model (lung-specific conditional Brg1 (Brg1-/-) knockdown mice) and human bronchial epithelial 16HBE cells stably expressing Brg1 shRNA. Our results showed that high expression of Brg1 was detected in asthmatic children and in mouse models. Brg1-/- mice showed improved airway hyperresponsiveness (AHR) and bronchial epithelial integrity, along with reduced inflammatory cell infiltration and airway mucus secretion, when challenged with OVA. Furthermore, cell proliferation, migration, and expression of E-cadherin increased in 16HBE cells in which Brg1 was silenced. We further demonstrated that Brg1 bound to and inactivated a critical region (-86/+60 bp) within the E-cadherin promoter in bronchial epithelial cells. Thus, Brg1 might act as an important regulator of airway epithelial integrity in asthma progression and might be a novel therapeutic target. KEY MESSAGES • Depletion of Brg1 improves the integrity of airway epithelium in asthma by regulating E-cadherin expression in lung epithelial cells. • Knockdown of Brg1 increased the cell proliferation and migration by human bronchial epithelial 16HBE cells. • Brg1 might bLLe a novel therapeutic target in asthma.
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9
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Wu Q, Lian JB, Stein JL, Stein GS, Nickerson JA, Imbalzano AN. The BRG1 ATPase of human SWI/SNF chromatin remodeling enzymes as a driver of cancer. Epigenomics 2017; 9:919-931. [PMID: 28521512 PMCID: PMC5705788 DOI: 10.2217/epi-2017-0034] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mammalian SWI/SNF enzymes are ATP-dependent remodelers of chromatin structure. These multisubunit enzymes are heterogeneous in composition; there are two catalytic ATPase subunits, BRM and BRG1, that are mutually exclusive, and additional subunits are incorporated in a combinatorial manner. Recent findings indicate that approximately 20% of human cancers contain mutations in SWI/SNF enzyme subunits, leading to the conclusion that the enzyme subunits are critical tumor suppressors. However, overexpression of specific subunits without apparent mutation is emerging as an alternative mechanism by which cellular transformation may occur. Here we highlight recent evidence linking elevated expression of the BRG1 ATPase to tissue-specific cancers and work suggesting that inhibiting BRG1 may be an effective therapeutic strategy.
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Affiliation(s)
- Qiong Wu
- Department of Pediatrics, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
| | - Jane B Lian
- Department of Biochemistry, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
| | - Janet L Stein
- Department of Biochemistry, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
| | - Gary S Stein
- Department of Biochemistry, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
| | - Jeffrey A Nickerson
- Department of Pediatrics, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
| | - Anthony N Imbalzano
- Department of Biochemistry & Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
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10
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Nickerson JA, Wu Q, Imbalzano AN. Mammalian SWI/SNF Enzymes and the Epigenetics of Tumor Cell Metabolic Reprogramming. Front Oncol 2017; 7:49. [PMID: 28421159 PMCID: PMC5378717 DOI: 10.3389/fonc.2017.00049] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 03/09/2017] [Indexed: 01/27/2023] Open
Abstract
Tumor cells reprogram their metabolism to survive and grow in a challenging microenvironment. Some of this reprogramming is performed by epigenetic mechanisms. Epigenetics is in turn affected by metabolism; chromatin modifying enzymes are dependent on substrates that are also key metabolic intermediates. We have shown that the chromatin remodeling enzyme Brahma-related gene 1 (BRG1), an epigenetic regulator, is necessary for rapid breast cancer cell proliferation. The mechanism for this requirement is the BRG1-dependent transcription of key lipogenic enzymes and regulators. Reduction in lipid synthesis lowers proliferation rates, which can be restored by palmitate supplementation. This work has established BRG1 as an attractive target for breast cancer therapy. Unlike genetic alterations, epigenetic mechanisms are reversible, promising gentler therapies without permanent off-target effects at distant sites.
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Affiliation(s)
- Jeffrey A Nickerson
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Qiong Wu
- Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA, USA
| | - Anthony N Imbalzano
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
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11
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Barutcu AR, Lajoie BR, Fritz AJ, McCord RP, Nickerson JA, van Wijnen AJ, Lian JB, Stein JL, Dekker J, Stein GS, Imbalzano AN. SMARCA4 regulates gene expression and higher-order chromatin structure in proliferating mammary epithelial cells. Genome Res 2016; 26:1188-201. [PMID: 27435934 PMCID: PMC5052043 DOI: 10.1101/gr.201624.115] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 07/08/2016] [Indexed: 01/20/2023]
Abstract
The packaging of DNA into chromatin plays an important role in transcriptional regulation and nuclear processes. Brahma-related gene-1 SMARCA4 (also known as BRG1), the essential ATPase subunit of the mammalian SWI/SNF chromatin remodeling complex, uses the energy from ATP hydrolysis to disrupt nucleosomes at target regions. Although the transcriptional role of SMARCA4 at gene promoters is well-studied, less is known about its role in higher-order genome organization. SMARCA4 knockdown in human mammary epithelial MCF-10A cells resulted in 176 up-regulated genes, including many related to lipid and calcium metabolism, and 1292 down-regulated genes, some of which encode extracellular matrix (ECM) components that can exert mechanical forces and affect nuclear structure. ChIP-seq analysis of SMARCA4 localization and SMARCA4-bound super-enhancers demonstrated extensive binding at intergenic regions. Furthermore, Hi-C analysis showed extensive SMARCA4-mediated alterations in higher-order genome organization at multiple resolutions. First, SMARCA4 knockdown resulted in clustering of intra- and inter-subtelomeric regions, demonstrating a novel role for SMARCA4 in telomere organization. SMARCA4 binding was enriched at topologically associating domain (TAD) boundaries, and SMARCA4 knockdown resulted in weakening of TAD boundary strength. Taken together, these findings provide a dynamic view of SMARCA4-dependent changes in higher-order chromatin organization and gene expression, identifying SMARCA4 as a novel component of chromatin organization.
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Affiliation(s)
- A Rasim Barutcu
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Bryan R Lajoie
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Andrew J Fritz
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
| | - Rachel P McCord
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Jeffrey A Nickerson
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Andre J van Wijnen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Jane B Lian
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
| | - Janet L Stein
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
| | - Job Dekker
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA; Howard Hughes Medical Institute, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Gary S Stein
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
| | - Anthony N Imbalzano
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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12
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Zhang Q, Kota KP, Alam SG, Nickerson JA, Dickinson RB, Lele TP. Coordinated Dynamics of RNA Splicing Speckles in the Nucleus. J Cell Physiol 2015; 231:1269-75. [PMID: 26496460 DOI: 10.1002/jcp.25224] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 10/21/2015] [Indexed: 12/28/2022]
Abstract
Despite being densely packed with chromatin, nuclear bodies and a nucleoskeletal network, the nucleus is a remarkably dynamic organelle. Chromatin loops form and relax, RNA transcripts and transcription factors move diffusively, and nuclear bodies move. We show here that RNA splicing speckled domains (splicing speckles) fluctuate in constrained nuclear volumes and remodel their shapes. Small speckles move in a directed way toward larger speckles with which they fuse. This directed movement is reduced upon decreasing cellular ATP levels or inhibiting RNA polymerase II activity. The random movement of speckles is reduced upon decreasing cellular ATP levels, moderately reduced after inhibition of SWI/SNF chromatin remodeling and modestly increased upon inhibiting RNA polymerase II activity. To define the paths through which speckles can translocate in the nucleus, we generated a pressure gradient to create flows in the nucleus. In response to the pressure gradient, speckles moved along curvilinear paths in the nucleus. Collectively, our results demonstrate a new type of ATP-dependent motion in the nucleus. We present a model where recycling splicing factors return as part of small sub-speckles from distal sites of RNA processing to larger splicing speckles by a directed ATP-driven mechanism through interchromatin spaces.
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Affiliation(s)
- Qiao Zhang
- Department of Chemical Engineering, University of Florida, Gainesville, Florida
| | - Krishna P Kota
- Department of Cellular and Tissue Imaging, Perkin Elmer Inc., Waltham, Massachusetts
| | - Samer G Alam
- Department of Chemical Engineering, University of Florida, Gainesville, Florida
| | - Jeffrey A Nickerson
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Richard B Dickinson
- Department of Chemical Engineering, University of Florida, Gainesville, Florida
| | - Tanmay P Lele
- Department of Chemical Engineering, University of Florida, Gainesville, Florida
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13
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Wu Q, Madany P, Akech J, Dobson JR, Douthwright S, Browne G, Colby JL, Winter GE, Bradner JE, Pratap J, Sluder G, Bhargava R, Chiosea SI, van Wijnen AJ, Stein JL, Stein GS, Lian JB, Nickerson JA, Imbalzano AN. The SWI/SNF ATPases Are Required for Triple Negative Breast Cancer Cell Proliferation. J Cell Physiol 2015; 230:2683-94. [PMID: 25808524 DOI: 10.1002/jcp.24991] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 03/18/2015] [Indexed: 12/30/2022]
Abstract
The Brahma (BRM) and Brahma-related Gene 1 (BRG1) ATPases are highly conserved homologs that catalyze the chromatin remodeling functions of the multi-subunit human SWI/SNF chromatin remodeling enzymes in a mutually exclusive manner. SWI/SNF enzyme subunits are mutated or missing in many cancer types, but are overexpressed without apparent mutation in other cancers. Here, we report that both BRG1 and BRM are overexpressed in most primary breast cancers independent of the tumor's receptor status. Knockdown of either ATPase in a triple negative breast cancer cell line reduced tumor formation in vivo and cell proliferation in vitro. Fewer cells in S phase and an extended cell cycle progression time were observed without any indication of apoptosis, senescence, or alterations in migration or attachment properties. Combined knockdown of BRM and BRG1 showed additive effects in the reduction of cell proliferation and time required for completion of cell cycle, suggesting that these enzymes promote cell cycle progression through independent mechanisms. Knockout of BRG1 or BRM using CRISPR/Cas9 technology resulted in the loss of viability, consistent with a requirement for both enzymes in triple negative breast cancer cells.
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Affiliation(s)
- Qiong Wu
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Pasil Madany
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Jacqueline Akech
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Jason R Dobson
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
- Department of Molecular Biology, Cell Biology and Biochemistry, Center for Computational Molecular Biology, Brown University, Providence, Rhode Island
- Department of Computer Science, Brown University, Providence, Rhode Island
| | - Stephen Douthwright
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Gillian Browne
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
- Department of Biochemistry and Vermont Cancer Center for Basic and Translational Research, University of Vermont College of Medicine, Burlington, Vermont
| | - Jennifer L Colby
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Georg E Winter
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts
| | - James E Bradner
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Jitesh Pratap
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
- Department of Anatomy and Cell Biology, Rush University, Chicago, Illinois
| | - Greenfield Sluder
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Rohit Bhargava
- Department of Pathology, Magee-Womens Hospital, Pittsburgh, Pennsylvania
| | - Simion I Chiosea
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Andre J van Wijnen
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
- Departments of Orthopedic Surgery & Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Janet L Stein
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
- Department of Biochemistry and Vermont Cancer Center for Basic and Translational Research, University of Vermont College of Medicine, Burlington, Vermont
| | - Gary S Stein
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
- Department of Biochemistry and Vermont Cancer Center for Basic and Translational Research, University of Vermont College of Medicine, Burlington, Vermont
| | - Jane B Lian
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
- Department of Biochemistry and Vermont Cancer Center for Basic and Translational Research, University of Vermont College of Medicine, Burlington, Vermont
- Department of Orthopedics and Physical Rehabilitation, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Jeffrey A Nickerson
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Anthony N Imbalzano
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts
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14
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Smith CL, Matheson TD, Trombly DJ, Sun X, Campeau E, Han X, Yates JR, Kaufman PD. A separable domain of the p150 subunit of human chromatin assembly factor-1 promotes protein and chromosome associations with nucleoli. Mol Biol Cell 2014; 25:2866-81. [PMID: 25057015 PMCID: PMC4161520 DOI: 10.1091/mbc.e14-05-1029] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Chromatin assembly factor-1 contains a separable domain unrelated to histone deposition, which provides a previously unrecognized ability to maintain nucleolar protein and chromosome associations. Chromatin assembly factor-1 (CAF-1) is a three-subunit protein complex conserved throughout eukaryotes that deposits histones during DNA synthesis. Here we present a novel role for the human p150 subunit in regulating nucleolar macromolecular interactions. Acute depletion of p150 causes redistribution of multiple nucleolar proteins and reduces nucleolar association with several repetitive element–containing loci. Of note, a point mutation in a SUMO-interacting motif (SIM) within p150 abolishes nucleolar associations, whereas PCNA or HP1 interaction sites within p150 are not required for these interactions. In addition, acute depletion of SUMO-2 or the SUMO E2 ligase Ubc9 reduces α-satellite DNA association with nucleoli. The nucleolar functions of p150 are separable from its interactions with the other subunits of the CAF-1 complex because an N-terminal fragment of p150 (p150N) that cannot interact with other CAF-1 subunits is sufficient for maintaining nucleolar chromosome and protein associations. Therefore these data define novel functions for a separable domain of the p150 protein, regulating protein and DNA interactions at the nucleolus.
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Affiliation(s)
- Corey L Smith
- Program in Gene Function and Expression, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Timothy D Matheson
- Program in Gene Function and Expression, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Daniel J Trombly
- Program in Gene Function and Expression, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Xiaoming Sun
- Program in Gene Function and Expression, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Eric Campeau
- Program in Gene Function and Expression, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Xuemei Han
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037
| | - John R Yates
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037
| | - Paul D Kaufman
- Program in Gene Function and Expression, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
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15
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Renganathan A, Kresoja-Rakic J, Echeverry N, Ziltener G, Vrugt B, Opitz I, Stahel RA, Felley-Bosco E. GAS5 long non-coding RNA in malignant pleural mesothelioma. Mol Cancer 2014; 13:119. [PMID: 24885398 PMCID: PMC4039656 DOI: 10.1186/1476-4598-13-119] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 05/19/2014] [Indexed: 12/29/2022] Open
Abstract
Background Malignant pleural mesothelioma (MPM) is an aggressive cancer with short overall survival. Long non-coding RNAs (lncRNA) are a class of RNAs more than 200 nucleotides long that do not code for protein and are part of the 90% of the human genome that is transcribed. Earlier experimental studies in mice showed GAS5 (growth arrest specific transcript 5) gene deletion in asbestos driven mesothelioma. GAS5 encodes for a lncRNA whose function is not well known, but it has been shown to act as glucocorticoid receptor decoy and microRNA “sponge”. Our aim was to investigate the possible role of the GAS5 in the growth of MPM. Methods Primary MPM cultures grown in serum-free condition in 3% oxygen or MPM cell lines grown in serum-containing medium were used to investigate the modulation of GAS5 by growth arrest after inhibition of Hedgehog or PI3K/mTOR signalling. Cell cycle length was determined by EdU incorporation assay in doxycycline inducible short hairpinGAS5 clones generated from ZL55SPT cells. Gene expression was quantified by quantitative PCR. To investigate the GAS5 promoter, a 0.77 kb sequence was inserted into a pGL3 reporter vector and luciferase activity was determined after transfection into MPM cells. Localization of GAS5 lncRNA was identified by in situ hybridization. To characterize cells expressing GAS5, expression of podoplanin and Ki-67 was assessed by immunohistochemistry. Results GAS5 expression was lower in MPM cell lines compared to normal mesothelial cells. GAS5 was upregulated upon growth arrest induced by inhibition of Hedgehog and PI3K/mTOR signalling in in vitro MPM models. The increase in GAS5 lncRNA was accompanied by increased promoter activity. Silencing of GAS5 increased the expression of glucocorticoid responsive genes glucocorticoid inducible leucine-zipper and serum/glucocorticoid-regulated kinase-1 and shortened the length of the cell cycle. Drug induced growth arrest was associated with GAS5 accumulation in the nuclei. GAS5 was abundant in tumoral quiescent cells and it was correlated to podoplanin expression. Conclusions The observations that GAS5 levels modify cell proliferation in vitro, and that GAS5 expression in MPM tissue is associated with cell quiescence and podoplanin expression support a role of GAS5 in MPM biology.
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Affiliation(s)
| | | | | | | | | | | | | | - Emanuela Felley-Bosco
- Laboratory of Molecular Oncology, Clinic of Oncology, University Hospital Zürich, Zürich, Switzerland.
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16
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Damiano L, Stewart KM, Cohet N, Mouw JK, Lakins JN, Debnath J, Reisman D, Nickerson JA, Imbalzano AN, Weaver VM. Oncogenic targeting of BRM drives malignancy through C/EBPβ-dependent induction of α5 integrin. Oncogene 2014; 33:2441-53. [PMID: 23770848 PMCID: PMC3960370 DOI: 10.1038/onc.2013.220] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 05/04/2013] [Accepted: 05/07/2013] [Indexed: 02/06/2023]
Abstract
Integrin expression and activity are altered in tumors, and aberrant integrin signaling promotes malignancy. However, how integrins become altered in tumors remains poorly understood. We discovered that oncogenic activation of MEK signaling induces cell growth and survival, and promotes the malignant phenotype of mammary epithelial cells (MECs) by increasing α5 integrin expression. We determined that MEK activates c-Myc to reduce the transcription of the SWI/SNF chromatin remodeling enzyme Brahma (BRM). Our studies revealed that reduced BRM expression and/or activity drives the malignant behavior of MECs by epigenetically promoting C/EBPβ expression to directly induce α5 integrin transcription. Consistently, we could show that restoring BRM levels normalized the malignant behavior of transformed MECs in culture and in vivo by preventing C/EBPβ-dependent α5 integrin transcription. Our findings identify a novel mechanism whereby oncogenic signaling promotes malignant transformation by regulating transcription of a key chromatin remodeling molecule that regulates integrin-dependent stromal-epithelial interactions.
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Affiliation(s)
- L Damiano
- Department of Surgery, Center for Bioengineering and Tissue Regeneration, University of California–San Francisco, San Francisco, CA, USA
| | - KM Stewart
- Department of Surgery, Center for Bioengineering and Tissue Regeneration, University of California–San Francisco, San Francisco, CA, USA
| | - N Cohet
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - JK Mouw
- Department of Surgery, Center for Bioengineering and Tissue Regeneration, University of California–San Francisco, San Francisco, CA, USA
| | - JN Lakins
- Department of Surgery, Center for Bioengineering and Tissue Regeneration, University of California–San Francisco, San Francisco, CA, USA
| | - J Debnath
- Department of Pathology, University of California–San Francisco, San Francisco, CA, USA
| | - D Reisman
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Gainesville, FL, USA
| | - JA Nickerson
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - AN Imbalzano
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - VM Weaver
- Department of Surgery, Center for Bioengineering and Tissue Regeneration, University of California–San Francisco, San Francisco, CA, USA
- Department of Anatomy, Bioengineering and Therapeutic Sciences, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Helen Diller Family Comprehensive Cancer Center, University of California–San Francisco, San Francisco, CA, USA
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17
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Imbalzano KM, Cohet N, Wu Q, Underwood JM, Imbalzano AN, Nickerson JA. Nuclear shape changes are induced by knockdown of the SWI/SNF ATPase BRG1 and are independent of cytoskeletal connections. PLoS One 2013; 8:e55628. [PMID: 23405182 PMCID: PMC3566038 DOI: 10.1371/journal.pone.0055628] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 01/02/2013] [Indexed: 11/24/2022] Open
Abstract
Changes in nuclear morphology occur during normal development and have been observed during the progression of several diseases. The shape of a nucleus is governed by the balance of forces exerted by nuclear-cytoskeletal contacts and internal forces created by the structure of the chromatin and nuclear envelope. However, factors that regulate the balance of these forces and determine nuclear shape are poorly understood. The SWI/SNF chromatin remodeling enzyme ATPase, BRG1, has been shown to contribute to the regulation of overall cell size and shape. Here we document that immortalized mammary epithelial cells show BRG1-dependent nuclear shape changes. Specifically, knockdown of BRG1 induced grooves in the nuclear periphery that could be documented by cytological and ultrastructural methods. To test the hypothesis that the observed changes in nuclear morphology resulted from altered tension exerted by the cytoskeleton, we disrupted the major cytoskeletal networks and quantified the frequency of BRG1-dependent changes in nuclear morphology. The results demonstrated that disruption of cytoskeletal networks did not change the frequency of BRG1-induced nuclear shape changes. These findings suggest that BRG1 mediates control of nuclear shape by internal nuclear mechanisms that likely control chromatin dynamics.
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Affiliation(s)
- Karen M Imbalzano
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
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18
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Serber DW, Rogala A, Makarem M, Rosson GB, Simin K, Godfrey V, Van Dyke T, Eaves CJ, Bultman SJ. The BRG1 chromatin remodeler protects against ovarian cysts, uterine tumors, and mammary tumors in a lineage-specific manner. PLoS One 2012; 7:e31346. [PMID: 22363625 PMCID: PMC3283619 DOI: 10.1371/journal.pone.0031346] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 01/06/2012] [Indexed: 12/27/2022] Open
Abstract
The BRG1 catalytic subunit of SWI/SNF-related complexes is required for mammalian development as exemplified by the early embryonic lethality of Brg1 null homozygous mice. BRG1 is also a tumor suppressor and, in mice, 10% of heterozygous (Brg1(null/+)) females develop mammary tumors. We now demonstrate that BRG1 mRNA and protein are expressed in both the luminal and basal cells of the mammary gland, raising the question of which lineage requires BRG1 to promote mammary homeostasis and prevent oncogenic transformation. To investigate this question, we utilized Wap-Cre to mutate both Brg1 floxed alleles in the luminal cells of the mammary epithelium of pregnant mice where WAP is exclusively expressed within the mammary gland. Interestingly, we found that Brg1(Wap-Cre) conditional homozygotes lactated normally and did not develop mammary tumors even when they were maintained on a Brm-deficient background. However, Brg1(Wap-Cre) mutants did develop ovarian cysts and uterine tumors. Analysis of these latter tissues showed that both, like the mammary gland, contain cells that normally express Brg1 and Wap. Thus, tumor formation in Brg1 mutant mice appears to be confined to particular cell types that require BRG1 and also express Wap. Our results now show that such cells exist both in the ovary and the uterus but not in either the luminal or the basal compartments of the mammary gland. Taken together, these findings indicate that SWI/SNF-related complexes are dispensable in the luminal cells of the mammary gland and therefore argue against the notion that SWI/SNF-related complexes are essential for cell survival. These findings also suggest that the tumor-suppressor activity of BRG1 is restricted to the basal cells of the mammary gland and demonstrate that this function extends to other female reproductive organs, consistent with recent observations of recurrent ARID1A/BAF250a mutations in human ovarian and endometrial tumors.
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Affiliation(s)
- Daniel W. Serber
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Allison Rogala
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Maisam Makarem
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gary B. Rosson
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Karl Simin
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Virginia Godfrey
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Terry Van Dyke
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Connie J. Eaves
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Scott J. Bultman
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
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19
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Nandakumar V, Kelbauskas L, Hernandez KF, Lintecum KM, Senechal P, Bussey KJ, Davies PCW, Johnson RH, Meldrum DR. Isotropic 3D nuclear morphometry of normal, fibrocystic and malignant breast epithelial cells reveals new structural alterations. PLoS One 2012; 7:e29230. [PMID: 22242161 PMCID: PMC3252316 DOI: 10.1371/journal.pone.0029230] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Accepted: 11/22/2011] [Indexed: 01/13/2023] Open
Abstract
Background Grading schemes for breast cancer diagnosis are predominantly based on pathologists' qualitative assessment of altered nuclear structure from 2D brightfield microscopy images. However, cells are three-dimensional (3D) objects with features that are inherently 3D and thus poorly characterized in 2D. Our goal is to quantitatively characterize nuclear structure in 3D, assess its variation with malignancy, and investigate whether such variation correlates with standard nuclear grading criteria. Methodology We applied micro-optical computed tomographic imaging and automated 3D nuclear morphometry to quantify and compare morphological variations between human cell lines derived from normal, benign fibrocystic or malignant breast epithelium. To reproduce the appearance and contrast in clinical cytopathology images, we stained cells with hematoxylin and eosin and obtained 3D images of 150 individual stained cells of each cell type at sub-micron, isotropic resolution. Applying volumetric image analyses, we computed 42 3D morphological and textural descriptors of cellular and nuclear structure. Principal Findings We observed four distinct nuclear shape categories, the predominant being a mushroom cap shape. Cell and nuclear volumes increased from normal to fibrocystic to metastatic type, but there was little difference in the volume ratio of nucleus to cytoplasm (N/C ratio) between the lines. Abnormal cell nuclei had more nucleoli, markedly higher density and clumpier chromatin organization compared to normal. Nuclei of non-tumorigenic, fibrocystic cells exhibited larger textural variations than metastatic cell nuclei. At p<0.0025 by ANOVA and Kruskal-Wallis tests, 90% of our computed descriptors statistically differentiated control from abnormal cell populations, but only 69% of these features statistically differentiated the fibrocystic from the metastatic cell populations. Conclusions Our results provide a new perspective on nuclear structure variations associated with malignancy and point to the value of automated quantitative 3D nuclear morphometry as an objective tool to enable development of sensitive and specific nuclear grade classification in breast cancer diagnosis.
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Affiliation(s)
- Vivek Nandakumar
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona, United States of America
- Center for Biosignatures Discovery Automation, Biodesign Institute, Tempe, Arizona, United States of America
| | - Laimonas Kelbauskas
- Center for Biosignatures Discovery Automation, Biodesign Institute, Tempe, Arizona, United States of America
| | - Kathryn F. Hernandez
- Center for Biosignatures Discovery Automation, Biodesign Institute, Tempe, Arizona, United States of America
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Kelly M. Lintecum
- Center for Biosignatures Discovery Automation, Biodesign Institute, Tempe, Arizona, United States of America
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Patti Senechal
- Center for Biosignatures Discovery Automation, Biodesign Institute, Tempe, Arizona, United States of America
| | - Kimberly J. Bussey
- Center for Biosignatures Discovery Automation, Biodesign Institute, Tempe, Arizona, United States of America
- Clinical Translational Research Division, Translational Genomics Research Institute, Phoenix, Arizona, United States of America
| | - Paul C. W. Davies
- Department of Physics, Arizona State University, Tempe, Arizona, United States of America
| | - Roger H. Johnson
- Center for Biosignatures Discovery Automation, Biodesign Institute, Tempe, Arizona, United States of America
- * E-mail:
| | - Deirdre R. Meldrum
- School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona, United States of America
- Center for Biosignatures Discovery Automation, Biodesign Institute, Tempe, Arizona, United States of America
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20
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Sims JK, Wade PA. Mi-2/NuRD complex function is required for normal S phase progression and assembly of pericentric heterochromatin. Mol Biol Cell 2011; 22:3094-102. [PMID: 21737684 PMCID: PMC3164457 DOI: 10.1091/mbc.e11-03-0258] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
During chromosome duplication, it is essential to replicate not only the DNA sequence, but also the complex nucleoprotein structures of chromatin. Pericentric heterochromatin is critical for silencing repetitive elements and plays an essential structural role during mitosis. However, relatively little is understood about its assembly and maintenance during replication. The Mi2/NuRD chromatin remodeling complex tightly associates with actively replicating pericentric heterochromatin, suggesting a role in its assembly. Here we demonstrate that depletion of the catalytic ATPase subunit CHD4/Mi-2β in cells with a dampened DNA damage response results in a slow-growth phenotype characterized by delayed progression through S phase. Furthermore, we observe defects in pericentric heterochromatin maintenance and assembly. Our data suggest that chromatin assembly defects are sensed by an ATM-dependent intra-S phase chromatin quality checkpoint, resulting in a temporal block to the transition from early to late S phase. These findings implicate Mi-2β in the maintenance of chromatin structure and proper cell cycle progression.
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Affiliation(s)
- Jennifer K Sims
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
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21
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The glucocorticoid receptor and the coregulator Brm selectively modulate each other's occupancy and activity in a gene-specific manner. Mol Cell Biol 2011; 31:3267-76. [PMID: 21646426 DOI: 10.1128/mcb.05351-11] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The diverse transcriptional patterns that distinguish metazoan cells are specified by multifactor regulatory complexes containing distinct combinations of factors that assemble at genomic response elements. To investigate combinatorial control, we examined a set of glucocorticoid receptor (GR)-regulated genes bearing nearby regulatory complexes that include both GR and the coregulator Brm, an ATPase subunit of the Swi/Snf chromatin remodeler. We analyzed how GR and Brm affect each other's occupancy and activity by utilizing glucocorticoid treatment and Brm knockdown to modulate GR-mediated transcriptional regulation and Brm-mediated chromatin remodeling, respectively. GR occupancy and activity were altered differentially by Brm knockdown at specific activated and repressed primary GR target genes. Brm knockdown decreased GR occupancy at activated Brm-dependent genes, whereas we identified two classes of repressed genes, at which Brm knockdown either increased or decreased GR occupancy. Glucocorticoid treatment increased both Brm occupancy and chromatin accessibility at Brm-dependent and Brm-independent GR-regulated genes. However, chromatin remodeling activity decreased after Brm knockdown only at genes with Brm-dependent transcription. Our study revealed multiple distinct patterns of GR and Brm interdependence. Thus, monitoring as few as two factors within regulatory complexes is sufficient to reveal functionally distinct assemblies, providing an analytical method for gaining insights into combinatorial regulation.
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Abstract
MicroRNA-21 (miR-21) is a key regulator of oncogenic processes. It is significantly elevated in the majority of human tumors and functionally linked to cellular proliferation, survival and migration. In this study, we used two experimental-based strategies to search for novel miR-21 targets. On the one hand, we performed a proteomic approach using two-dimensional differential gel electrophoresis (2D-DIGE) to identify proteins suppressed upon enhanced miR-21 expression in LNCaP human prostate carcinoma cells. The tumor suppressor acidic nuclear phosphoprotein 32 family, member A (ANP32A) (alias pp32 or LANP) emerged as the most strongly downregulated protein. On the other hand, we applied a mathematical approach to select correlated gene sets that are negatively correlated with primary-miR-21 (pri-miR-21) expression in published transcriptome data from 114 B-cell lymphoma cases. Among these candidates, we found tumor suppressor SMARCA4 (alias BRG1) together with the already validated miR-21 target, PDCD4. ANP32A and SMARCA4, which are both involved in chromatin remodeling processes, were confirmed as direct miR-21 targets by immunoblot analysis and reporter gene assays. Furthermore, knock down of ANP32A mimicked the effect of enforced miR-21 expression by enhancing LNCaP cell viability, whereas overexpression of ANP32A in the presence of high miR-21 levels abrogated the miR-21-mediated effect. In A172 glioblastoma cells, enhanced ANP32A expression compensated for the effects of anti-miR-21 treatment on cell viability and apoptosis. In addition, miR-21 expression clearly increased the invasiveness of LNCaP cells, an effect also seen in part upon downregulation of ANP32A. In conclusion, these results suggest that downregulation of ANP32A contributes to the oncogenic function of miR-21.
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Xu YZ, Thuraisingam T, Marino R, Radzioch D. Recruitment of SWI/SNF complex is required for transcriptional activation of the SLC11A1 gene during macrophage differentiation of HL-60 cells. J Biol Chem 2011; 286:12839-49. [PMID: 21300803 DOI: 10.1074/jbc.m110.185637] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The solute carrier family 11 member 1 (SLC11A1) gene is strictly regulated and exclusively expressed in myeloid lineage cells. However, little is known about the transcriptional regulation of the SLC11A1 gene during myeloid development. In this study, we used HL-60 cells as a model to investigate the regulatory elements/factors involved in the transactivation of the SLC11A1 gene during phorbol 12-myristate 13-acetate (PMA)-induced macrophage differentiation of HL-60 cells. Promoter deletion analysis showed that a 7-base AP-1-like element (TGACTCT) was critical for the responsiveness of the SLC11A1 promoter to PMA. Stimulation by PMA induced the binding of ATF-3 and the recruitment of two components of the SWI/SNF complex, BRG1 and β-actin, to this element in an ATF-3-dependent manner. RNAi-mediated depletion of ATF-3 or BRG1 markedly decreased SLC11A1 gene expression and its promoter activity induced by PMA. Luciferase reporter experiments demonstrated that ATF-3 cooperated with BRG1 and β-actin to activate the SLC11A1 promoter. Furthermore, we showed that PMA can induce the proximal (GT/AC)(n) repeat sequence to convert to the Z-DNA structure in the SLC11A1 gene promoter, and depletion of BRG1 resulted in a significant decrease of Z-DNA formation. Our results demonstrated that recruitment of the SWI/SNF complex initiated Z-DNA formation and subsequently helped to transactivate the SLC11A1 gene.
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Affiliation(s)
- Yong Zhong Xu
- Division of Experimental Medicine, Department of Medicine, Montreal General Hospital Research Institute, McGill University, Montreal, Quebec H3G 1A4, Canada
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