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Nguyen VT, Tessema M, Weissman BE. The SWI/SNF Complex: A Frequently Mutated Chromatin Remodeling Complex in Cancer. Cancer Treat Res 2023; 190:211-244. [PMID: 38113003 DOI: 10.1007/978-3-031-45654-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
The switch/sucrose non-fermenting (SWI/SNF) chromatin remodeling complex is a global regulator of gene expression known to maintain nucleosome-depleted regions at active enhancers and promoters. The mammalian SWI/SNF protein subunits are encoded by 29 genes and 11-15 subunits including an ATPase domain of either SMARCA4 (BRG1) or SMARCA2 (BRM) are assembled into a complex. Based on the distinct subunits, SWI/SNF are grouped into 3 major types (subfamilies): the canonical BRG1/BRM-associated factor (BAF/cBAF), polybromo-associated BAF (PBAF), and non-canonical BAF (GBAF/ncBAF). Pan-cancer genome sequencing studies have shown that nearly 25% of all cancers bear mutations in subunits of the SWI/SNF complex, many of which are loss of function (LOF) mutations, suggesting a tumor suppressor role. Inactivation of SWI/SNF complex subunits causes widespread epigenetic dysfunction, including increased dependence on antagonistic components such as polycomb repressor complexes (PRC1/2) and altered enhancer regulation, likely promoting an oncogenic state leading to cancer. Despite the prevalence of mutations, most SWI/SNF-mutant cancers lack targeted therapeutic strategies. Defining the dependencies created by LOF mutations in SWI/SNF subunits will identify better targets for these cancers.
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Affiliation(s)
- Vinh The Nguyen
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
- Curriculum in Toxicology and Environmental Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
| | - Mathewos Tessema
- Lung Cancer Program, Lovelace Biomedical Research Institute, Albuquerque, NM, USA
| | - Bernard Ellis Weissman
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA.
- Curriculum in Toxicology and Environmental Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA.
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA.
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2
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Domovitz T, Gal-Tanamy M. Tracking Down the Epigenetic Footprint of HCV-Induced Hepatocarcinogenesis. J Clin Med 2021; 10:jcm10030551. [PMID: 33540858 PMCID: PMC7867330 DOI: 10.3390/jcm10030551] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/17/2021] [Accepted: 01/28/2021] [Indexed: 02/07/2023] Open
Abstract
Hepatitis C virus (HCV) is a major cause of death and morbidity globally and is a leading cause of hepatocellular carcinoma (HCC). Incidence of HCV infections, as well as HCV-related liver diseases, are increasing. Although now, with new direct acting antivirals (DAAs) therapy available, HCV is a curable cancer-associated infectious agent, HCC prevalence is expected to continue to rise because HCC risk still persists after HCV cure. Understanding the factors that lead from HCV infection to HCC pre- and post-cure may open-up opportunities to novel strategies for HCC prevention. Herein, we provide an overview of the reported evidence for the induction of alterations in the transcriptome of host cells via epigenetic dysregulation by HCV infection and describe recent reports linking the residual risk for HCC post-cure with a persistent HCV-induced epigenetic signature. Specifically, we discuss the contribution of the epigenetic changes identified following HCV infection to HCC risk pre- and post-cure, the molecular pathways that are epigenetically altered, the downstream effects on expression of cancer-related genes, the identification of targets to prevent or revert this cancer-inducing epigenetic signature, and the potential contribution of these studies to early prognosis and prevention of HCC as an approach for reducing HCC-related mortality.
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3
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Ciechomska IA, Jayaprakash C, Maleszewska M, Kaminska B. Histone Modifying Enzymes and Chromatin Modifiers in Glioma Pathobiology and Therapy Responses. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1202:259-279. [PMID: 32034718 DOI: 10.1007/978-3-030-30651-9_13] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Signal transduction pathways directly communicate and transform chromatin to change the epigenetic landscape and regulate gene expression. Chromatin acts as a dynamic platform of signal integration and storage. Histone modifications and alteration of chromatin structure play the main role in chromatin-based gene expression regulation. Alterations in genes coding for histone modifying enzymes and chromatin modifiers result in malfunction of proteins that regulate chromatin modification and remodeling. Such dysregulations culminate in profound changes in chromatin structure and distorted patterns of gene expression. Gliomagenesis is a multistep process, involving both genetic and epigenetic alterations. Recent applications of next generation sequencing have revealed that many chromatin regulation-related genes, including ATRX, ARID1A, SMARCA4, SMARCA2, SMARCC2, BAF155 and hSNF5 are mutated in gliomas. In this review we summarize newly identified mechanisms affecting expression or functions of selected histone modifying enzymes and chromatin modifiers in gliomas. We focus on selected examples of pathogenic mechanisms involving ATRX, histone methyltransferase G9a, histone acetylases/deacetylases and chromatin remodeling complexes SMARCA2/4. We discuss the impact of selected epigenetics alterations on glioma pathobiology, signaling and therapeutic responses. We assess the attempts of targeting defective pathways with new inhibitors.
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Affiliation(s)
- Iwona A Ciechomska
- Laboratory of Molecular Neurobiology, Neurobiology Center, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Chinchu Jayaprakash
- Laboratory of Molecular Neurobiology, Neurobiology Center, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Marta Maleszewska
- Laboratory of Molecular Neurobiology, Neurobiology Center, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Bozena Kaminska
- Laboratory of Molecular Neurobiology, Neurobiology Center, Nencki Institute of Experimental Biology, Warsaw, Poland.
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4
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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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5
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Fang R, Xia Q, Sun J, Ng HZ, Liang Y, Wang X, Wang X, Ma H, Zhou X, Cheng Y, Rao Q. Hypermethylation of BRM promoter plays oncogenic roles in development of clear cell renal cell carcinoma. J Cancer 2019; 10:5256-5263. [PMID: 31602276 PMCID: PMC6775622 DOI: 10.7150/jca.30098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 07/06/2019] [Indexed: 11/29/2022] Open
Abstract
Although the inactivation of BRM plays oncogenic roles in tumorigenesis, regulation mechanism is rarely studied in clear cell renal cell carcinoma (RCC). Thus, we aimed to investigate the mechanism of BRM inactivation and explore the tumor suppressing roles of BRM in the development of clear cell RCC. We verified that hypermethylation of the BRM promoter was correlated with decreased expression of BRM by multi-omics analysis based on the TCGA database. This result was further confirmed in our own tumor tissues. Moreover, BRM inhibited the ability of proliferation and invasion of RCC cells in vitro. Consistent with this, BRM overexpressing virtually inhibited the xenograft tumor growth of ACHN cells in vivo. Finally we found that BRM promoted cell apoptosis and cellular cycle arrest in G2/M. In conclusion, our study confirms that the hypermethylation of BRM promoters plays oncogenic roles by the transcription inhibition of BRM in RCC, and the tumor suppressor gene BRM inhibits RCC cell vitality in vitro and in vivo.
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Affiliation(s)
- Ru Fang
- Department of Pathology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, Jiangsu, China
| | - Qiuyuan Xia
- Department of Pathology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, Jiangsu, China
| | - Jing Sun
- Department of Medical Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Hao Zha Ng
- Sir Run Run Shaw Hospital Affiliated to Nanjing Medical University, Nanjing, 210029, China
| | - Yan Liang
- Department of Pathology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, Jiangsu, China
| | - Xiaotong Wang
- Department of Pathology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, Jiangsu, China
| | - Xuan Wang
- Department of Pathology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, Jiangsu, China
| | - Henghui Ma
- Department of Pathology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, Jiangsu, China
| | - Xiaojun Zhou
- Department of Pathology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, Jiangsu, China
| | - Yang Cheng
- Center for Health Management, Geriatric Hospital of Nanjing Medical University, Nanjing, 210009, China
| | - Qiu Rao
- Department of Pathology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, 210002, Jiangsu, China
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6
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Takeda M, Tani Y, Saijo N, Shimizu S, Taniguchi Y, Otsuka K, Nakao K, Tamiya A, Okishio K, Atagi S, Ohbayashi C, Kasai T. Cytopathological Features of SMARCA4-Deficient Thoracic Sarcoma: Report of 2 Cases and Review of the Literature. Int J Surg Pathol 2019; 28:109-114. [PMID: 31448657 DOI: 10.1177/1066896919870866] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
SMARCA4-deficient thoracic sarcoma (SMARCA4-DTS) is a recently described entity of thoracic sarcomas with an undifferentiated rhabdoid morphology and SMARCA4 inactivation. Regardless of some reports about the histopathological findings so far, there have been only a few reports about the cytological features. In this article, we present the pathological features of 2 SMARCA4-DTS cases, including the cytological findings. Histopathologically, the tumor cells showed atypical loosely cohesive large epithelioid cells focally with geographic necrosis. Some cells were characterized by rhabdoid cells. Both patients showed intrathoracic masses with a history of smoking, and loss of SMARCA4 expression was confirmed with histopathological specimens. Immunohistochemically, tumor cells of both cases were at least focally positive for cytokeratin, CD34, CD99, synaptophysin, SOX2, and SALL4. In addition, tumor cells demonstrated significantly reduced expression of BRG1/SMARCA4 and SMARCA2. In conclusion, SMARCA4-DTS should be taken into consideration in the differential diagnosis of tumors with undifferentiated rhabdoid morphology involving the thoracic region.
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Affiliation(s)
- Maiko Takeda
- National Hospital Organization Kinki-chuo Chest Medical Center, Sakai, Japan
| | - Yoko Tani
- National Hospital Organization Kinki-chuo Chest Medical Center, Sakai, Japan.,Osaka City University, Osaka, Japan
| | - Nobuhiko Saijo
- National Hospital Organization Kinki-chuo Chest Medical Center, Sakai, Japan
| | | | - Yoshihiko Taniguchi
- National Hospital Organization Kinki-chuo Chest Medical Center, Sakai, Japan
| | - Kenji Otsuka
- National Hospital Organization Kinki-chuo Chest Medical Center, Sakai, Japan.,Tokushima University, Tokushima, Japan
| | - Keiko Nakao
- National Hospital Organization Kinki-chuo Chest Medical Center, Sakai, Japan
| | - Akihiro Tamiya
- National Hospital Organization Kinki-chuo Chest Medical Center, Sakai, Japan
| | - Kyoichi Okishio
- National Hospital Organization Kinki-chuo Chest Medical Center, Sakai, Japan
| | - Shinji Atagi
- National Hospital Organization Kinki-chuo Chest Medical Center, Sakai, Japan
| | | | - Takahiko Kasai
- National Hospital Organization Kinki-chuo Chest Medical Center, Sakai, Japan
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7
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Lee MJ, Kuehne N, Hueniken K, Liang S, Rai S, Sorotsky H, Herman M, Shepshelovich D, Bruce J, Liang M, Patel D, Cheng D, Chen Z, Eng L, Brown MC, Cho J, Leighl NB, de Perrot M, Reisman D, Xu W, Bradbury PA, Liu G. Association of two BRM promoter polymorphisms and smoking status with malignant pleural mesothelioma risk and prognosis. Mol Carcinog 2019; 58:1960-1973. [PMID: 31355511 DOI: 10.1002/mc.23088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 06/29/2019] [Accepted: 07/09/2019] [Indexed: 11/06/2022]
Abstract
Brahma (BRM), of the SWI/SNF complex, has two 6 to 7 bp insertion promoter polymorphisms (BRM-741/BRM-1321) that cause epigenetic BRM suppression, and are associated with risk of multiple cancers. BRM polymorphisms were genotyped in malignant pleural mesothelioma (MPM) cases and asbestos-exposed controls. Multivariable logistic regression (risk) and Cox regression (prognosis) were performed, including stratified analyses by smoking status to investigate the effect of polymorphisms on MPM risk and prognosis. Although there was no significant association overall between BRM-741/BRM-1321 and risk in patients with MPM, a differential effect by smoking status was observed (P-interaction < .001), where homozygous variants were protective (aOR of 0.18-0.28) in ever smokers, while never smokers had increased risk when carrying homozygous variants (aOR of 2.7-4.4). While there was no association between BRM polymorphisms and OS in ever-smokers, the aHR of carrying homozygous-variants of BRM-741, BRM-1321 or both were 4.0 to 8.6 in never-smokers when compared to wild-type carriers. Mechanistically, lower mRNA expression of BRM was associated with poorer general cancer prognosis. Electrophoretic mobility shift assays and chromatin immunoprecipitation experiments (ChIP) revealed high BRM insertion variant homology to MEF2 regulatory binding sites. ChIP experimentation confirmed MEF2 binding only occurs in the presence of insertion variants. DNA-affinity purification assays revealed YWHA scaffold proteins as vital to BRM mRNA expression. Never-smokers who carry BRM homozygous variants have an increased chance of developing MPM, which results in worse prognosis. In contrast, in ever-smokers, there may be a protective effect, with no difference in overall survival. Mechanisms for the interaction between BRM and smoking require further study.
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Affiliation(s)
- Min Joon Lee
- Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.,Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Nathan Kuehne
- Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Katrina Hueniken
- Department of Medical Biophysics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Shermi Liang
- Division of Hematology and Oncology, Department of Medicine, University of Florida, Gainesville, Florida
| | - Sudhir Rai
- Division of Hematology and Oncology, Department of Medicine, University of Florida, Gainesville, Florida
| | - Hadas Sorotsky
- Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Michael Herman
- Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Daniel Shepshelovich
- Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Jeffrey Bruce
- Department of Medical Biophysics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Mindy Liang
- Department of Medical Biophysics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Devalben Patel
- Department of Medical Biophysics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Dangxiao Cheng
- Department of Medical Biophysics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Zhuo Chen
- Department of Medical Biophysics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Lawson Eng
- Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - M Catherine Brown
- Department of Medical Biophysics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - John Cho
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Natasha B Leighl
- Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Marc de Perrot
- Division of Thoracic Surgery, Department of Surgery, University Health Network, Toronto, ON, Canada
| | - David Reisman
- Division of Hematology and Oncology, Department of Medicine, University of Florida, Gainesville, Florida
| | - Wei Xu
- Department of Biostatistics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Penelope A Bradbury
- Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Geoffrey Liu
- Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.,Department of Medical Biophysics, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.,Department of Epidemiology, Dalla Lana School of Public Health, Toronto, ON, Canada
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8
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Mei L, Alikhan M, Mujacic I, Parilla M, Antic T. Genomic Alterations in Undifferentiated Malignant Tumors with Rhabdoid Phenotype and Loss of BRG1 Immunoexpression Identified by Fine Needle Aspirates. Acta Cytol 2019; 63:438-444. [PMID: 31230044 DOI: 10.1159/000500684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 04/30/2019] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Evidence shows that the switch/sucrose nonfermenting chromatin remodeling complex plays a critical role in DNA repair, cancer progression and dedifferentiation. BRG1 is one of its key catalytic subunits. While the loss of BRG1 expression by immunocytochemistry has been identified in a subset of malignancies arising in various sites with undifferentiated/rhabdoid morphology and poor prognosis, the underlying basis for its loss is unclear. METHODS A retrospective search was conducted in our cytopathology archive for undifferentiated malignant tumors with rhabdoid phenotype and BRG1 loss. Clinical information was obtained from electronic medical records. Next-generation sequencing was performed following macro-dissection of paraffin-embedded cellblock tissue. RESULTS Three cases were identified; all presented with widely metastatic disease with no previously diagnosed primary malignancy, and subsequently died within 6 months of initial presentation. Cytologically, the aspirates showed dyshesive and undifferentiated cells with rhabdoid features. Extensive immunocytochemical workup demonstrated immunoreactivity with vimentin only and could not establish a specific lineage. BRG1 expression was absent, while INI1 expression was retained. Two cases harbored deleterious mutations in BRG1/SMARCA4. Pathogenic mutations in TP53 were identified in all tumors. CONCLUSIONS BRG1 deficiency reflects underlying mutation in SMARCA4 gene in some but not all cases, suggesting that additional mechanisms may be causing BRG1 silencing. Pathogenic mutations in TP53 in all tumors are consistent with their highly aggressive nature. Recognizing the cytomorphology of this group of neoplasms and confirming their BRG1-deficient status by immunocytochemistry not only has prognostic implications, but may also impart potentially therapeutic value in the near future.
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Affiliation(s)
- Lily Mei
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
| | - Mir Alikhan
- Department of Pathology and Laboratory Medicine, NorthShore University HealthSystem, Evanston, Illinois, USA
| | - Ibro Mujacic
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
| | - Megan Parilla
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
| | - Tatjana Antic
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA,
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9
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Perez S, Gal-Tanamy M. Studying the Hepatitis C Virus-Induced Epigenetic Signature After Cure with Direct-Acting Antivirals. Methods Mol Biol 2019; 1911:191-207. [PMID: 30593627 DOI: 10.1007/978-1-4939-8976-8_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hepatitis C virus (HCV) is the leading cause of hepatocellular carcinoma (HCC). While direct-acting antiviral (DAA) therapy efficiently eradicates HCV infection, epidemiological studies show that sustained virological response (SVR) following anti-HCV treatment reduces, but does not eliminate, the risk for HCC. We have recently demonstrated that HCV infection induces genome-wide epigenetic changes that reprogram host gene expression and persist as "epigenetic signature" following virus eradication by DAAs. We suggest that this epigenetic signature underlie the residual risk for HCC post-SVR. Here, we provide a methodology to study the HCV-induced epigenetic signature. We describe a ChIP-seq protocol to evaluate changes in epigenome profile following HCV infection, its cure with DAA, and after treatment with epigenetic modifier inhibitor. We also describe evaluation of changes in the gene expression profile using RNA-seq. The integration between detected alterations in epigenetic marks and gene expression allows for identification of biological processes that are involved in HCV-driven oncogenesis before and after cure.
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Affiliation(s)
- Shira Perez
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Meital Gal-Tanamy
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel.
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10
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Korpanty GJ, Eng L, Qiu X, Faluyi OO, Renouf DJ, Cheng D, Patel D, Chen Z, Tse BC, Knox JJ, Dodbiba L, Teichman J, Azad AK, Wong R, Darling G, Reisman D, Cuffe S, Liu G, Xu W. Association of BRM promoter polymorphisms and esophageal adenocarcinoma outcome. Oncotarget 2018; 8:28093-28100. [PMID: 28427211 PMCID: PMC5438633 DOI: 10.18632/oncotarget.15890] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 02/22/2017] [Indexed: 12/16/2022] Open
Abstract
Purpose Brahma (BRM) is a critical catalytic subunit of the SWI/SNF chromatin remodeling complex; expression of BRM is commonly lost in various cancer types. BRM promoter polymorphisms (BRM-741; BRM-1321) are associated with loss of BRM expression, and with cancer risk/survival. We evaluated these two polymorphisms in the overall survival (OS) of esophageal adenocarcinoma (EAC) patients. Results Of 270 patients, 37% were stage IV. Minor allele frequencies were 47−49%; 15% were double-homozygotes. When compared to the wild-type genotype, the homozygous variant of BRM-741 carried an adjusted OS hazard ratio (aHR) of 1.64 (95% CI:1.1−2.4); for BRM-1321, the aHR was 2.09 (95% CI:1.4−3.0). Compared to the double wild-type, carrying homozygous variants of both promoter polymorphisms (double-homozygote) yielded an aHR of 2.21 (95% CI:1.4−3.6). Directions/magnitudes of associations were similar in subsets by age, gender, smoking status, use of platinum agents, and disease stage, and for progression-free survival. Materials and Methods In a cohort of EAC patients of all stages (84% male; median age of 64 years), two BRM polymorphisms were genotyped. Cox proportional hazards models, adjusted for known prognostic variables, estimated the association of polymorphisms with OS. Conclusions BRM polymorphisms were associated with OS in EAC in this study. Validation studies are warranted.
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Affiliation(s)
- Grzegorz J Korpanty
- Princess Margaret Cancer Centre, Department of Medicine, University Health Network, Toronto, ON, Canada.,Canadian Cancer Trials Group, Department of Medicine, Queens University, Kingston, ON, Canada
| | - Lawson Eng
- Princess Margaret Cancer Centre, Department of Medicine, University Health Network, Toronto, ON, Canada
| | - Xin Qiu
- Princess Margaret Cancer Centre, Department of Biostatistics, University Health Network, Toronto, ON, Canada
| | - Olusola Olusesan Faluyi
- Princess Margaret Cancer Centre, Department of Medicine, University Health Network, Toronto, ON, Canada
| | - Daniel J Renouf
- Department of Medical Oncology, University of British Columbia and British Columbia Cancer Agency, Vancouver, BC, Canada
| | - Dangxiao Cheng
- Princess Margaret Cancer Centre, Department of Medical Biophysics, University Health Network, Toronto, ON, Canada
| | - Devalben Patel
- Princess Margaret Cancer Centre, Department of Medical Biophysics, University Health Network, Toronto, ON, Canada
| | - Zhuo Chen
- Princess Margaret Cancer Centre, Department of Medical Biophysics, University Health Network, Toronto, ON, Canada
| | - Brandon C Tse
- Princess Margaret Cancer Centre, Department of Medical Biophysics, University Health Network, Toronto, ON, Canada
| | - Jennifer J Knox
- Princess Margaret Cancer Centre, Department of Medicine, University Health Network, Toronto, ON, Canada
| | - Lorin Dodbiba
- Princess Margaret Cancer Centre, Department of Medicine, University Health Network, Toronto, ON, Canada
| | - Jennifer Teichman
- Princess Margaret Cancer Centre, Department of Medicine, University Health Network, Toronto, ON, Canada
| | - Abul Kalam Azad
- Princess Margaret Cancer Centre, Department of Medicine, University Health Network, Toronto, ON, Canada
| | - Rebecca Wong
- Princess Margaret Cancer Centre, Radiation Medicine Program, University Health Network, Toronto, ON, Canada
| | - Gail Darling
- Department of Surgery, Division of Thoracic Surgery, Toronto General Hospital, University Health Network, Toronto, ON, Canada
| | - David Reisman
- Department of Medicine in the College of Medicine, Division of Hematology and Oncology, University of Florida, Gainesville, FL, USA
| | - Sinead Cuffe
- Princess Margaret Cancer Centre, Department of Medicine, University Health Network, Toronto, ON, Canada
| | - Geoffrey Liu
- Princess Margaret Cancer Centre, Department of Medicine, University Health Network, Toronto, ON, Canada.,Princess Margaret Cancer Centre, Department of Medical Biophysics, University Health Network, Toronto, ON, Canada.,Department of Epidemiology, Dalla Lana School of Pubic Health, Toronto, ON, Canada
| | - Wei Xu
- Princess Margaret Cancer Centre, Department of Biostatistics, University Health Network, Toronto, ON, Canada
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11
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PRC2-mediated repression of SMARCA2 predicts EZH2 inhibitor activity in SWI/SNF mutant tumors. Proc Natl Acad Sci U S A 2017; 114:12249-12254. [PMID: 29087303 DOI: 10.1073/pnas.1703966114] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Subunits of the SWI/SNF chromatin remodeling complex are frequently mutated in human cancers leading to epigenetic dependencies that are therapeutically targetable. The dependency on the polycomb repressive complex (PRC2) and EZH2 represents one such vulnerability in tumors with mutations in the SWI/SNF complex subunit, SNF5; however, whether this vulnerability extends to other SWI/SNF subunit mutations is not well understood. Here we show that a subset of cancers harboring mutations in the SWI/SNF ATPase, SMARCA4, is sensitive to EZH2 inhibition. EZH2 inhibition results in a heterogenous phenotypic response characterized by senescence and/or apoptosis in different models, and also leads to tumor growth inhibition in vivo. Lower expression of the SMARCA2 paralog was associated with cellular sensitivity to EZH2 inhibition in SMARCA4 mutant cancer models, independent of tissue derivation. SMARCA2 is suppressed by PRC2 in sensitive models, and induced SMARCA2 expression can compensate for SMARCA4 and antagonize PRC2 targets. The induction of SMARCA2 in response to EZH2 inhibition is required for apoptosis, but not for growth arrest, through a mechanism involving the derepression of the lysomal protease cathepsin B. Expression of SMARCA2 also delineates EZH2 inhibitor sensitivity for other SWI/SNF complex subunit mutant tumors, including SNF5 and ARID1A mutant cancers. Our data support monitoring SMARCA2 expression as a predictive biomarker for EZH2-targeted therapies in the context of SWI/SNF mutant cancers.
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12
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Pasic I, Wong KM, Lee JJ, Espin-Garcia O, Brhane Y, Cheng D, Chen Z, Patel D, Brown C, Bucur R, Reisman D, Knox JJ, Xu W, Hung RJ, Liu G, Cleary SP. Two BRM promoter polymorphisms predict poor survival in patients with hepatocellular carcinoma. Mol Carcinog 2017; 57:106-113. [PMID: 28892201 DOI: 10.1002/mc.22736] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 09/06/2017] [Indexed: 01/13/2023]
Abstract
Polymorphisms in the promoter of the BRM gene, a critical subunit of the chromatin remodeling SWI/SNF complex, have previously been implicated in risk and prognosis in Caucasian-predominant lung, head and neck, esophageal, and pancreatic cancers, and in hepatocellular cancers in Asians. We investigated the role of these polymorphisms in hepatocellular carcinoma (HCC) risk and prognosis. HCC cases were recruited in a comprehensive cancer center while the matched controls were recruited from family practice units from the same catchment area. For risk analyses, unconditional logistic regression analyses were performed in HCC patients and matched healthy controls. Overall survival analyses were performed using Cox proportional hazard models, Kaplan-Meier curves, and log-rank tests. In 266 HCC cases and 536 controls, no association between either BRM promoter polymorphism (BRM-741 or BRM-1321) and risk of HCC was identified (P > 0.10 for all comparisons). There was significant worsening of overall survival as the number of variant alleles increased: BRM-741 per variant allele adjusted hazards ratio (aHR) 5.77, 95% confidence interval (CI) 2.89-11.54 and BRM-1321 per variant allele aHR 4.09, 95%CI 2.22-7.51. The effects of these two polymorphisms were at least additive, where individuals who were double homozygotes for the variant alleles had a 45-fold increase in risk of death when compared to those who were double wild-type for the two polymorphisms. Two BRM promoter polymorphisms were strongly associated with HCC prognosis but were not associated with increased HCC susceptibility. The association was strongest in double homozygotes for the allele variants.
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Affiliation(s)
- Ivan Pasic
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,University of Toronto, Toronto, Canada
| | - Kit M Wong
- Department of Medical Oncology, University of Washington, Seattle, Washington
| | - Jonghun J Lee
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Osvaldo Espin-Garcia
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,University of Toronto, Toronto, Canada
| | - Yonathan Brhane
- Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Dangxiao Cheng
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Zhuo Chen
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Devalben Patel
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Catherine Brown
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Roxana Bucur
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | | | - Jennifer J Knox
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Wei Xu
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Rayjean J Hung
- Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Geoffrey Liu
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,University of Toronto, Toronto, Canada
| | - Sean P Cleary
- Department of Surgery, Mayo Clinic College of Medicine, Rochester, Minnesota
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13
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SMARCA4-deficient thoracic sarcoma: a distinctive clinicopathological entity with undifferentiated rhabdoid morphology and aggressive behavior. Mod Pathol 2017; 30:1422-1432. [PMID: 28643792 DOI: 10.1038/modpathol.2017.61] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 04/27/2017] [Accepted: 04/27/2017] [Indexed: 01/19/2023]
Abstract
A distinct subset of thoracic sarcomas with undifferentiated rhabdoid morphology and SMARCA4 inactivation has recently been described, and potential targeted therapy for SMARC-deficient tumors is emerging. We sought to validate the clinicopathological features of SMARCA4-deficient thoracic sarcomas. Clinicopathological information was gathered for 40 undifferentiated thoracic tumors with rhabdoid morphology (mediastinum (n=18), lung (n=14), pleura (n=8)). Thymic carcinomas (n=11) were used as a comparison group. Immunohistochemistry included BRG1 (SMARCA4), BRM (SMARCA2), INI-1 (SMARCB1), pan-cytokeratin, desmin, NUT, S-100 protein, TTF1, CD34, and SOX2. BRG1 loss was present in 12 of 40 rhabdoid thoracic tumors (30%): 7 of 18 in mediastinum (39%), 2 of 8 in pleura (25%), and 3 of 14 in lung (21%). All BRG1-deficient tumors tested for BRM (n=8) showed concomitant loss. All thymic carcinomas showed retained BRG1 and INI-1. Morphologically, tumors with BRG1 loss showed sheets of monotonous ovoid cells with indistinct cell borders, abundant eosinophilic cytoplasm, and prominent nucleoli. Scattered areas with rhabdoid morphology (ie, eccentric nuclei, dense eosinophilic cytoplasm, discohesion) were present in all the cases. SMARCA4/BRG1-deficient sarcomas showed rare cells positive for cytokeratin in 10 cases (83%). One showed rare TTF1-positive cells. All were negative for desmin, NUT, and S-100 protein. CD34 was positive in three of five (60%) BRG1-deficient tumors tested. SOX2 was positive in all four BRG1-deficient tumors tested, and negative in all seven tested cases with retained BRG1. SMARCA4/BRG1-deficient sarcomas occurred at median age of 59 years (range 44-76) with male predominance (9:3) and had worse 2-year survival compared with BRG1-retained tumors (12.5% vs 64.4%, P=0.02). SMARCA4-deficient thoracic sarcomas can be identified based on their distinctive high-grade rhabdoid morphology, and the diagnosis can be confirmed by immunohistochemistry. Identification of these tumors is clinically relevant due to their aggressive behavior, poor prognosis, and potential targeted therapy.
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14
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Zhang Z, Wang F, Du C, Guo H, Ma L, Liu X, Kornmann M, Tian X, Yang Y. BRM/SMARCA2 promotes the proliferation and chemoresistance of pancreatic cancer cells by targeting JAK2/STAT3 signaling. Cancer Lett 2017; 402:213-224. [PMID: 28602977 DOI: 10.1016/j.canlet.2017.05.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 05/01/2017] [Accepted: 05/12/2017] [Indexed: 12/23/2022]
Abstract
BACKGROUND BRM is one of two evolutionarily conserved catalytic ATPase subunits of SWI/SNF complexes and plays important role in cell proliferation, linage specification and development, cell adhesion, cytokine responses and DNA repair. BRM is often inactivated in various types of cancer indicating its indispensable roles in oncogenesis but the mechanisms remain poorly understood. METHODS BRM expression in clinical pancreatic cancer samples was examined by immunohistochemistry and the correlation with patient survival was analyzed. shRNAs targeting BRM were used to establish stable BRM knockdown BxPC-3 and T3M4 cell lines. Cell viability was assessed by CCK-8 assay. Cell proliferation was measured by EdU incorporation assay, colony formation assay and Ki67 staining. Cell cycle and apoptosis were examined by flow cytometry. Growth and chemosensitivity of xenografts initiating from BRM-deficient cells were evaluated, and in situ apoptosis was detected by TUNEL assay. The status of JAK-STAT3 signaling was examined by real-time PCR and Western blot analysis. RESULTS High BRM expression was correlated with worse survival of pancreatic cancer patients. BRM shRNA reduced the proliferation and increased the sensitivity of pancreatic cancer cells to gemcitabine in vivo and in vitro, and these effects are associated with the inhibition of STAT3 phosphorylation and reduced transcription of STAT3 target genes. CONCLUSION We reveal a novel mechanism by which BRM could activate JAK2/STAT3 pathway to promote pancreatic cancer growth and chemoresistance. These findings may offer potential therapeutic targets for pancreatic cancer patients with excessive BRM expression.
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Affiliation(s)
- Zhengkui Zhang
- Department of General Surgery, Peking University First Hospital, Beijing 100034, People's Republic of China
| | - Feng Wang
- Department of General Surgery, Peking University First Hospital, Beijing 100034, People's Republic of China
| | - Chong Du
- Department of General Surgery, Peking University First Hospital, Beijing 100034, People's Republic of China
| | - Huahu Guo
- Department of General Surgery, Peking University First Hospital, Beijing 100034, People's Republic of China
| | - Ling Ma
- Department of Surgical Oncology, Peking University Ninth School of Clinical Medicine (Beijing Shijitan Hospital, Capital Medical University), Beijing 100038, People's Republic of China
| | - Xiaoran Liu
- Department of Breast Oncology, Peking University Cancer Hospital & Institute, Beijing 100142, People's Republic of China
| | - Marko Kornmann
- Clinic of General, Visceral and Transplantation Surgery, University of Ulm, Ulm 89081, Germany
| | - Xiaodong Tian
- Department of General Surgery, Peking University First Hospital, Beijing 100034, People's Republic of China.
| | - Yinmo Yang
- Department of General Surgery, Peking University First Hospital, Beijing 100034, People's Republic of China.
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15
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Xia QY, Zhan XM, Fan XS, Ye SB, Shi SS, Li R, Wei X, Wang X, Ma HH, Lu ZF, Zhou XJ, Rao Q. BRM/SMARCA2-negative clear cell renal cell carcinoma is associated with a high percentage of BRM somatic mutations, deletions and promoter methylation. Histopathology 2017; 70:711-721. [PMID: 28070921 DOI: 10.1111/his.13120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 10/25/2016] [Accepted: 11/03/2016] [Indexed: 11/27/2022]
Abstract
AIMS The aim of this study was to investigate potential molecular mechanisms associated with loss of BRM expression in poorly differentiated clear cell renal cell carcinoma (ccRCC). METHODS AND RESULTS Nineteen previously selected BRM-negative RCC tissues were examined by DNA sequencing, fluorescence in-situ hybridization (FISH) and methylation-specific polymerase chain reaction (PCR) of the BRM gene. BRM mutation was identified in 78.9% (15 of 19) cases, chromosome 9 monosomy or BRM deletion in 43.8% (seven of 16) and BRM promoter region cytosine-phosphate-guanine (CpG) methylation in 42.8% (six of 14). These results indicated that 89.5% (17 of 19) of the cases harboured at least one type of BRM genetic alteration, with two or more types of alteration in 47.4% (nine of 19). Such alterations were found rarely in adjacent non-neoplastic tissues and low-grade areas of composite tumours. CONCLUSIONS BRM gene mutation, chromosome 9 monosomy or BRM deletion and CpG methylation contribute collectively to the loss of BRM expression in ccRCC. This work focusing on composite tumours indicated that BRM abnormality occurred during tumour progression.
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Affiliation(s)
- Qiu-Yuan Xia
- Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xue-Mei Zhan
- Department of Pathology, Linyi People's Hospital, Linyi, China
| | - Xiang-Shan Fan
- Department of Pathology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School Nanjing City, Nanjing, China
| | - Sheng-Bing Ye
- Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Shan-Shan Shi
- Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Rui Li
- Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xue Wei
- Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xuan Wang
- Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Heng-Hui Ma
- Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Zhen-Feng Lu
- Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xiao-Jun Zhou
- Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Qiu Rao
- Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
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16
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Liu G, Cuffe S, Liang S, Azad AK, Cheng L, Brhane Y, Qiu X, Cescon DW, Bruce J, Chen Z, Cheng D, Patel D, Tse BC, Laurie SA, Goss G, Leighl NB, Hung R, Bradbury PA, Seymour L, Shepherd FA, Tsao MS, Chen BE, Xu W, Reisman DN. BRM Promoter Polymorphisms and Survival of Advanced Non-Small Cell Lung Cancer Patients in the Princess Margaret Cohort and CCTG BR.24 Trial. Clin Cancer Res 2016; 23:2460-2470. [PMID: 27827316 DOI: 10.1158/1078-0432.ccr-16-1640] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/04/2016] [Accepted: 10/23/2016] [Indexed: 01/08/2023]
Abstract
Introduction: BRM, a key catalytic subunit of the SWI/SNF chromatin remodeling complex, is a putative tumor susceptibility gene that is silenced in 15% of non-small cell lung cancer (NSCLC). Two novel BRM promoter polymorphisms (BRM-741 and BRM-1321) are associated with reversible epigenetic silencing of BRM protein expression.Experimental Design: Advanced NSCLC patients from the Princess Margaret (PM) cohort study and from the CCTG BR.24 clinical trial were genotyped for BRM promoter polymorphisms. Associations of BRM variants with survival were assessed using log-rank tests, the method of Kaplan and Meier, and Cox proportional hazards models. Promoter swap, luciferase assays, and chromatin immunoprecipitation (ChIP) experiments evaluated polymorphism function. In silico analysis of publicly available gene expression datasets with outcome were performed.Results: Carrying the homozygous variants of both polymorphisms ("double homozygotes", DH) when compared with those carrying the double wild-type was associated with worse overall survival, with an adjusted hazard ratios (aHR) of 2.74 (95% CI, 1.9-4.0). This was confirmed in the BR.24 trial (aHR, 8.97; 95% CI, 3.3-18.5). Lower BRM gene expression (by RNA-Seq or microarray) was associated with worse outcome (P < 0.04). ChIP and promoter swap experiments confirmed binding of MEF2D and HDAC9 only to homozygotes of each polymorphism, associated with reduced promoter activity in the DH.Conclusions: Epigenetic regulatory molecules bind to two BRM promoter sequence variants but not to their wild-type sequences. These variants are associated with adverse overall and progression-free survival. Decreased BRM gene expression, seen with these variants, is also associated with worse overall survival. Clin Cancer Res; 23(10); 2460-70. ©2016 AACR.
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Affiliation(s)
- Geoffrey Liu
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada.
- Ontario Cancer Institute, Toronto, Ontario, Canada
| | - Sinead Cuffe
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
| | | | - Abul Kalam Azad
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
- Ontario Cancer Institute, Toronto, Ontario, Canada
| | - Lu Cheng
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Yonathan Brhane
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Xin Qiu
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - David W Cescon
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
- Ontario Cancer Institute, Toronto, Ontario, Canada
| | - Jeffrey Bruce
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
- Ontario Cancer Institute, Toronto, Ontario, Canada
| | - Zhuo Chen
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
- Ontario Cancer Institute, Toronto, Ontario, Canada
| | - Dangxiao Cheng
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
- Ontario Cancer Institute, Toronto, Ontario, Canada
| | - Devalben Patel
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
- Ontario Cancer Institute, Toronto, Ontario, Canada
| | - Brandon C Tse
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
- Ontario Cancer Institute, Toronto, Ontario, Canada
| | | | - Glenwood Goss
- Ottawa Hospital Cancer Centre, Ottawa, Ontario, Canada
| | - Natasha B Leighl
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Rayjean Hung
- Lunenfeld Research Institute and Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Penelope A Bradbury
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Lesley Seymour
- Canadian Cancer Trials Group, Queens University, Kingston, Ontario, Canada
| | - Frances A Shepherd
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
- Ontario Cancer Institute, Toronto, Ontario, Canada
| | - Ming Sound Tsao
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
- Ontario Cancer Institute, Toronto, Ontario, Canada
| | - Bingshu E Chen
- Canadian Cancer Trials Group, Queens University, Kingston, Ontario, Canada
| | - Wei Xu
- Princess Margaret Cancer Centre and University Health Network, University of Toronto, Toronto, Ontario, Canada
- Ontario Cancer Institute, Toronto, Ontario, Canada
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17
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Segedi M, Anderson LN, Espin-Garcia O, Borgida A, Bianco T, Cheng D, Chen Z, Patel D, Brown MC, Xu W, Reisman D, Gallinger S, Cotterchio M, Hung R, Liu G, Cleary SP. BRM polymorphisms, pancreatic cancer risk and survival. Int J Cancer 2016; 139:2474-81. [PMID: 27487558 DOI: 10.1002/ijc.30369] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 05/31/2016] [Accepted: 06/20/2016] [Indexed: 12/30/2022]
Abstract
Variant alleles of two promoter polymorphisms in the BRM gene (BRM-741, BRM-1321), create MEF2D transcription binding sites that lead to epigenetic silencing of BRM, the key catalytic component of the SWI/SNF chromatin remodeling complex. BRM suppression can be reversed pharmacologically.(1) Our group and others have reported associations with lung, head and neck, hepatocellular cancer risk,(1-3) and with lung and esophageal cancer prognosis (ASCO 2013; abstract 11057 & 4077). Herein, we assessed risk and survival associations with pancreatic cancer. A provincial population-based case-control study was conducted with 623 histologically confirmed pancreatic adenocarcinoma cases and 1,192 age/gender distribution-matched controls.(4) Survival of cases was obtained through the Ontario Cancer Registry. Logistic and Cox proportional hazard regression models were fitted, adjusting for relevant covariates. Median age was 65 y; 52% were male; Stage I (8%), II (55%), III (14%), IV (23%); 53% after curative resection, 79% after chemotherapy; and 83% had died. In the risk analysis, adjusted odds ratios (aOR) were 1.01 (95% CI: 0.1-2.0) and 0.96 (95% CI: 0.7-1.3) for the homozygotes of BRM-741 and BRM-1321, respectively; aOR of double-homozygotes was 1.11 (95% CI: 0.80-1.53), compared to the double-wildtype. For the survival analysis, adjusted hazard ratios (aHR) were 2.19 (95% CI: 1.9-2.5) for BRM-741 and 1.94 (95% CI: 1.7-2.2) for BRM-1321, per unit increase in variant alleles. Compared with the double-wildtype, aHR for carrying no, one, and two double-homozygotes were 2.14 (95% CI: 1.6-2.8), 4.17 (95% CI: 3.0-5.7), 8.03 (95% CI: 5.7-11.4), respectively. In conclusion, two functional promoter BRM polymorphisms were not associated with pancreatic adenocarcinoma risk, but are strongly associated with survival.
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Affiliation(s)
- Maja Segedi
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada.,Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada
| | - Laura N Anderson
- Mount Sinai Hospital-Lunenfeld Research Institute, Toronto, ON, Canada
| | - Osvaldo Espin-Garcia
- Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada
| | - Ayelet Borgida
- Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada.,Mount Sinai Hospital-Lunenfeld Research Institute, Toronto, ON, Canada
| | - Teresa Bianco
- Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada.,Mount Sinai Hospital-Lunenfeld Research Institute, Toronto, ON, Canada
| | - Dangxiao Cheng
- Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada
| | - Zhuo Chen
- Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada
| | - Devalben Patel
- Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada
| | - M Catherine Brown
- Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada
| | - Wei Xu
- Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada
| | - David Reisman
- Medical Oncology, University of Florida, Gainesville, FL
| | - Steven Gallinger
- Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada.,Mount Sinai Hospital-Lunenfeld Research Institute, Toronto, ON, Canada
| | | | - Rayjean Hung
- Mount Sinai Hospital-Lunenfeld Research Institute, Toronto, ON, Canada
| | - Geoffrey Liu
- Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada.
| | - Sean P Cleary
- Princess Margaret Cancer Centre-University Health Network-Ontario Cancer Institute, University of Toronto, Toronto, ON, Canada.,Mount Sinai Hospital-Lunenfeld Research Institute, Toronto, ON, Canada
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18
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Epigenomic regulation of oncogenesis by chromatin remodeling. Oncogene 2016; 35:4423-36. [PMID: 26804164 DOI: 10.1038/onc.2015.513] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/27/2015] [Accepted: 12/07/2015] [Indexed: 02/08/2023]
Abstract
Disruption of the intricate gene expression program represents one of major driving factors for the development, progression and maintenance of human cancer, and is often associated with acquired therapeutic resistance. At the molecular level, cancerous phenotypes are the outcome of cellular functions of critical genes, regulatory interactions of histones and chromatin remodeling complexes in response to dynamic and persistent upstream signals. A large body of genetic and biochemical evidence suggests that the chromatin remodelers integrate the extracellular and cytoplasmic signals to control gene activity. Consequently, widespread dysregulation of chromatin remodelers and the resulting inappropriate expression of regulatory genes, together, lead to oncogenesis. We summarize the recent developments and current state of the dysregulation of the chromatin remodeling components as the driving mechanism underlying the growth and progression of human tumors. Because chromatin remodelers, modifying enzymes and protein-protein interactions participate in interpreting the epigenetic code, selective chromatin remodelers and bromodomains have emerged as new frontiers for pharmacological intervention to develop future anti-cancer strategies to be used either as single-agent or in combination therapies with chemotherapeutics or radiotherapy.
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19
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Concomitant loss of SMARCA2 and SMARCA4 expression in small cell carcinoma of the ovary, hypercalcemic type. Mod Pathol 2016; 29:60-6. [PMID: 26564006 PMCID: PMC4697871 DOI: 10.1038/modpathol.2015.129] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 09/25/2015] [Accepted: 09/26/2015] [Indexed: 12/20/2022]
Abstract
Small cell carcinoma of the ovary, hypercalcemic type is an aggressive tumor generally affecting young women with limited treatment options. Mutations in SMARCA4, a catalytic subunit of the SWI/SNF chromatin remodeling complex, have recently been identified in nearly all small cell carcinoma of the ovary, hypercalcemic type cases and represent a signature molecular feature for this disease. Additional biological dependencies associated with small cell carcinoma of the ovary, hypercalcemic type have not been identified. SMARCA2, another catalytic subunit of the SWI/SNF complex mutually exclusive with SMARCA4, is thought to be post-translationally silenced in various cancer types. We analyzed 10 archival small cell carcinoma of the ovary, hypercalcemic type cases for SMARCA2 protein expression by immunohistochemistry and found that SMARCA2 expression was lost in all but one case. None of the 50 other tumors that primarily or secondarily involved the ovary demonstrated concomitant loss of SMARCA2 and SMARCA4. Deep sequencing revealed that this loss of SMARCA2 expression is not the result of mutational inactivation. In addition, we established a small cell carcinoma of the ovary, hypercalcemic type patient-derived xenograft and confirmed the loss of SMARCA2 in this in vitro model. This patient-derived xenograft model, established from a recurrent tumor, also had unexpected mutational features for this disease, including functional mutations in TP53 and POLE. Taken together, our data suggest that concomitant loss of SMARCA2 and SMARCA4 is another hallmark of small cell carcinoma of the ovary, hypercalcemic type-a finding that offers new opportunities for therapeutic interventions.
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20
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Thompson KW, Marquez SB, Lu L, Reisman D. Induction of functional Brm protein from Brm knockout mice. Oncoscience 2015; 2:349-61. [PMID: 26097869 PMCID: PMC4468321 DOI: 10.18632/oncoscience.153] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 04/08/2015] [Indexed: 12/18/2022] Open
Abstract
Once the knockout of the Brm gene was found to be nontumorigenic in mice, the study of BRM's involvement in cancer seemed less important compared with that of its homolog, Brg1. This has likely contributed to the disparity that has been observed in the publication ratio between BRG1 and BRM. We show that a previously published Brm knockout mouse is an incomplete knockout whereby a truncated isoform of Brm is detected in normal tissue and in tumors. We show that this truncated Brm isoform has functionality comparable to wild type Brm. By immunohistochemistry (IHC), this truncated Brm is undetectable in normal lung tissue and is minimal to very low in Brmnull tumors. However, it is significant in a subset (~40%) of Brg1/Brm double knockout (DKO) tumors that robustly express this truncated BRM, which in part stems from an increase in Brm mRNA levels. Thus, it is likely that this mutant mouse model does not accurately reflect the role that Brm plays in cancer development. We suggest that the construction of a completely new mouse Brm knockout, where Brm is functionally absent, is needed to determine whether or not Brm is actually tumorigenic and if Brm might be a tumor suppressor.
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Affiliation(s)
- Kenneth W. Thompson
- Division of Hematology and Oncology, Department of Medicine, University of Florida, Gainesville, Florida, USA
| | - Stefanie B. Marquez
- Division of Hematology and Oncology, Department of Medicine, University of Florida, Gainesville, Florida, USA
| | - Li Lu
- Department of Pathology, University of Florida, Gainesville, Florida, USA
| | - David Reisman
- Division of Hematology and Oncology, Department of Medicine, University of Florida, Gainesville, Florida, USA
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21
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Mayes K, Qiu Z, Alhazmi A, Landry JW. ATP-dependent chromatin remodeling complexes as novel targets for cancer therapy. Adv Cancer Res 2015; 121:183-233. [PMID: 24889532 DOI: 10.1016/b978-0-12-800249-0.00005-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The progression to advanced stage cancer requires changes in many characteristics of a cell. These changes are usually initiated through spontaneous mutation. As a result of these mutations, gene expression is almost invariably altered allowing the cell to acquire tumor-promoting characteristics. These abnormal gene expression patterns are in part enabled by the posttranslational modification and remodeling of nucleosomes in chromatin. These chromatin modifications are established by a functionally diverse family of enzymes including histone and DNA-modifying complexes, histone deposition pathways, and chromatin remodeling complexes. Because the modifications these enzymes deposit are essential for maintaining tumor-promoting gene expression, they have recently attracted much interest as novel therapeutic targets. One class of enzyme that has not generated much interest is the chromatin remodeling complexes. In this review, we will present evidence from the literature that these enzymes have both causal and enabling roles in the transition to advanced stage cancers; as such, they should be seriously considered as high-value therapeutic targets. Previously published strategies for discovering small molecule regulators to these complexes are described. We close with thoughts on future research, the field should perform to further develop this potentially novel class of therapeutic target.
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Affiliation(s)
- Kimberly Mayes
- Department of Human and Molecular Genetics, VCU Institute of Molecular Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Zhijun Qiu
- Department of Human and Molecular Genetics, VCU Institute of Molecular Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Aiman Alhazmi
- Department of Human and Molecular Genetics, VCU Institute of Molecular Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Joseph W Landry
- Department of Human and Molecular Genetics, VCU Institute of Molecular Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA.
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22
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Marquez SB, Thompson KW, Lu L, Reisman D. Beyond Mutations: Additional Mechanisms and Implications of SWI/SNF Complex Inactivation. Front Oncol 2015; 4:372. [PMID: 25774356 PMCID: PMC4343012 DOI: 10.3389/fonc.2014.00372] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 12/11/2014] [Indexed: 01/14/2023] Open
Abstract
UNLABELLED SWI/SNF is a major regulator of gene expression. Its role is to facilitate the shifting and exposure of DNA segments within the promoter and other key domains to transcription factors and other essential cellular proteins. This complex interacts with a wide range of proteins and does not function within a single, specific pathway; thus, it is involved in a multitude of cellular processes, including DNA repair, differentiation, development, cell adhesion, and growth control. Given SWI/SNF's prominent role in these processes, many of which are important for blocking cancer development, it is not surprising that the SWI/SNF complex is targeted during cancer initiation and progression both by mutations and by non-mutational mechanisms. Currently, the understanding of the types of alterations, their frequency, and their impact on the SWI/SNF subunits is an area of intense research that has been bolstered by a recent cadre of NextGen sequencing studies. These studies have revealed mutations in SWI/SNF subunits, indicating that this complex is thus important for cancer development. The purpose of this review is to put into perspective the role of mutations versus other mechanisms in the silencing of SWI/SNF subunits, in particular, BRG1 and BRM. In addition, this review explores the recent development of synthetic lethality and how it applies to this complex, as well as how BRM polymorphisms are becoming recognized as potential clinical biomarkers for cancer risk. SIGNIFICANCE Recent reviews have detailed the occurrence of mutations in nearly all SWI/SNF subunits, which indicates that this complex is an important target for cancer. However, when the frequency of mutations in a given tumor type is compared to the frequency of subunit loss, it becomes clear that other non-mutational mechanisms must play a role in the inactivation of SWI/SNF subunits. Such data indicate that epigenetic mechanisms that are known to regulate BRM may also be involved in the loss of expression of other SWI/SNF subunits. This is important since epigenetically silenced genes are inducible, and thus, the reversal of the silencing of these non-mutationally suppressed subunits may be a viable mode of targeted therapy.
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Affiliation(s)
- Stefanie B Marquez
- Department of Medicine, Division of Hematology/Oncology, University of Florida , Gainesville, FL , USA
| | - Kenneth W Thompson
- Department of Medicine, Division of Hematology/Oncology, University of Florida , Gainesville, FL , USA
| | - Li Lu
- Department of Pathology, University of Florida , Gainesville, FL , USA
| | - David Reisman
- Department of Medicine, Division of Hematology/Oncology, University of Florida , Gainesville, FL , USA
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23
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Rao Q, Xia QY, Wang ZY, Li L, Shen Q, Shi SS, Wang X, Liu B, Wang YF, Shi QL, Ma HH, Lu ZF, He Y, Zhang RS, Yu B, Zhou XJ. Frequent co-inactivation of the SWI/SNF subunits SMARCB1, SMARCA2 and PBRM1 in malignant rhabdoid tumours. Histopathology 2015; 67:121-9. [PMID: 25496315 DOI: 10.1111/his.12632] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/10/2014] [Indexed: 12/24/2022]
Affiliation(s)
- Qiu Rao
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Qiu-yuan Xia
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Zi-yu Wang
- School of Basic Medical Sciences; Nanjing University of Traditional Chinese Medicine; Nanjing China
| | - Li Li
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Qin Shen
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Shan-shan Shi
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Xuan Wang
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Biao Liu
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Yan-fen Wang
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Qun-li Shi
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Heng-hui Ma
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Zhen-feng Lu
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Yan He
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Ru-song Zhang
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Bo Yu
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Xiao-jun Zhou
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
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24
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Thompson KW, Marquez SB, Reisman D. A synthetic lethality-based strategy to treat cancers harboring a genetic deficiency in the chromatin remodeling factor BRG1--letter. Cancer Res 2014; 74:4946-7. [PMID: 25136073 DOI: 10.1158/0008-5472.can-13-2457] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Kenneth W Thompson
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Gainesville, Florida
| | - Stefanie B Marquez
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Gainesville, Florida
| | - David Reisman
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Gainesville, Florida.
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25
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Concurrent loss of INI1, PBRM1, and BRM expression in epithelioid sarcoma: implications for the cocontributions of multiple SWI/SNF complex members to pathogenesis. Hum Pathol 2014; 45:2247-54. [PMID: 25200863 DOI: 10.1016/j.humpath.2014.06.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 06/02/2014] [Accepted: 06/04/2014] [Indexed: 01/10/2023]
Abstract
The loss of INI1 (SMARCB1) expression, caused by SMARCB1 (INI1, SNF5L4, BAF47) inactivation, frequently occurs in epithelioid sarcoma (ES) and could aid in confirming the diagnosis. Except for INI1, the expression of switch in mating type/sucrose nonfermentation complex members in ES has never been examined. In this study, the expression of key subunits of this complex-INI1, BRG1 (SMARCA4), BRM (SNF2L2, SMARCA2), PBRM1 (hPB1, BAF180), and BAF155 (SMARCC1)-was analyzed in 23 ES cases: 15 conventional and 8 proximal type. All of the cases were reviewed and reclassified by hematoxylin-eosin staining and immunostaining for cytokeratin AE1/3, epithelial membrane antigen, CD34, vimentin, and INI1 expression. Of the 23 ES cases, 19 (82.6%) showed a loss of PBRM1, and 18 (78.3%), a loss of INI1. In most cases (17, 73.9%), loss of INI1 and PBRM1 expression was observed. The pattern of PBRM1 expression was similar to that of INI1, that is, not correlated with changes in cellular morphology. The concurrent loss of BRM, PBRM1, and INI1expression was detected in 2 cases with pure rhabdoid tumor features. The frequent observation of concurrent loss of INI1 and PBRM1 suggests that certain switch in mating type/sucrose nonfermentation complex components might act synergistically in the pathogenesis of ES by unknown mechanisms and that these components could provide new targets for therapy. The usefulness of PBRM1 as a biomarker of ES and its mechanism in ES require further investigation. Loss of BRM in ES with pure rhabdoid features suggests that BRM might be involved in the underlying mechanisms of this type of ES.
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26
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Mehrotra A, Saladi SV, Trivedi AR, Aras S, Qi H, Jayanthy A, Setaluri V, de la Serna IL. Modulation of Brahma expression by the mitogen-activated protein kinase/extracellular signal regulated kinase pathway is associated with changes in melanoma proliferation. Arch Biochem Biophys 2014; 563:125-35. [PMID: 25026375 DOI: 10.1016/j.abb.2014.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Revised: 07/03/2014] [Accepted: 07/06/2014] [Indexed: 10/25/2022]
Abstract
Brahma (BRM) and Brahma-related gene 1(BRG1) are catalytic subunits of SWItch/sucrose non-fermentable (SWI/SNF) chromatin remodeling complexes. BRM is epigenetically silenced in a wide-range of tumors. Mutations in the v-raf murine sarcoma viral oncogene homolog B1 (BRAF) gene occur frequently in melanoma and lead to constitutive activation of the mitogen-activated protein kinase (MAPK)/extracellular signal regulated kinase (ERK1/2) pathway. We tested the hypothesis that BRM expression is modulated by oncogenic BRAF and phosphorylation of ERK1/2 in melanocytes and melanoma cells. Expression of oncogenic BRAF in melanocytes and melanoma cells that are wild-type for BRAF decreased BRM expression and increased BRG1 expression. Inhibition of mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) or selective inhibition of BRAF in melanoma cells that harbor oncogenic BRAF increased BRM expression and decreased BRG1 expression. Increased BRM expression was associated with increased histone acetylation on the BRM promoter. Over-expression of BRM in melanoma cells that harbor oncogenic BRAF promoted changes in cell cycle progression and apoptosis consistent with a tumor suppressive role. Upon inhibition of BRAF(V600E) with PLX4032, BRM promoted survival. PLX4032 induced changes in BRM function were correlated with increased acetylation of the BRM protein. This study provides insights into the epigenetic consequences of inhibiting oncogenic BRAF in melanoma through modulation of SWI/SNF subunit expression and function.
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Affiliation(s)
- Aanchal Mehrotra
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States
| | - Srinivas Vinod Saladi
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States
| | - Archit R Trivedi
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States
| | - Shweta Aras
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States
| | - Huiling Qi
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States
| | - Ashika Jayanthy
- University of Wisconsin, Department of Dermatology, 1300 University Avenue, #439, Madison, WI 53706, United States
| | - Vijayasaradhi Setaluri
- University of Wisconsin, Department of Dermatology, 1300 University Avenue, #439, Madison, WI 53706, United States
| | - Ivana L de la Serna
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States.
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27
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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] [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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28
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Kahali B, Marquez SB, Thompson KW, Yu J, Gramling SJB, Lu L, Aponick A, Reisman D. Flavonoids from each of the six structural groups reactivate BRM, a possible cofactor for the anticancer effects of flavonoids. Carcinogenesis 2014; 35:2183-93. [PMID: 24876151 DOI: 10.1093/carcin/bgu117] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Flavonoids have been extensively studied and are well documented to have anticancer effects, but it is not entirely known how they impact cellular mechanisms to elicit these effects. In the course of this study, we found that a variety of different flavonoids readily restored Brahma (BRM) in BRM-deficient cancer cell lines. Flavonoids from each of the six different structural groups were effective at inducing BRM expression as well as inhibiting growth in these BRM-deficient cancer cells. By blocking the induction of BRM with shRNA, we found that flavonoid-induced growth inhibition was BRM dependent. We also found that flavonoids can restore BRM functionality by reversing BRM acetylation. In addition, we observed that an array of natural flavonoid-containing products both induced BRM expression as well as deacetylated the BRM protein. We also tested two of the BRM-inducing flavonoids (Rutin and Diosmin) at both a low and a high dose on the development of tumors in an established murine lung cancer model. We found that these flavonoids effectively blocked development of adenomas in the lungs of wild-type mice but not in that of BRMnull mice. These data demonstrate that BRM expression and function are regulated by flavonoids and that functional BRM appears to be a prerequisite for the anticancer effects of flavonoids both in vitro and in vivo.
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Affiliation(s)
- Bhaskar Kahali
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Office 294, Cancer/Genetics Building, 2033 Mowry Road, Gainesville, FL 32611, USA and Department of Pathology and Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Stefanie B Marquez
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Office 294, Cancer/Genetics Building, 2033 Mowry Road, Gainesville, FL 32611, USA and Department of Pathology and Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Kenneth W Thompson
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Office 294, Cancer/Genetics Building, 2033 Mowry Road, Gainesville, FL 32611, USA and Department of Pathology and Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Jinlong Yu
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Office 294, Cancer/Genetics Building, 2033 Mowry Road, Gainesville, FL 32611, USA and Department of Pathology and Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Sarah J B Gramling
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Office 294, Cancer/Genetics Building, 2033 Mowry Road, Gainesville, FL 32611, USA and Department of Pathology and Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Li Lu
- Department of Pathology and
| | - Aaron Aponick
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - David Reisman
- Division of Hematology/Oncology, Department of Medicine, University of Florida, Office 294, Cancer/Genetics Building, 2033 Mowry Road, Gainesville, FL 32611, USA and Department of Pathology and Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
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29
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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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30
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Wong KM, Qiu X, Cheng D, Azad AK, Habbous S, Palepu P, Mirshams M, Patel D, Chen Z, Roberts H, Knox J, Marquez S, Wong R, Darling G, Waldron J, Goldstein D, Leighl N, Shepherd FA, Tsao M, Der S, Reisman D, Liu G. Two BRM promoter insertion polymorphisms increase the risk of early-stage upper aerodigestive tract cancers. Cancer Med 2014; 3:426-33. [PMID: 24519853 PMCID: PMC3987092 DOI: 10.1002/cam4.201] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 12/04/2013] [Accepted: 12/26/2013] [Indexed: 12/23/2022] Open
Abstract
Brahma (BRM) has a key function in chromatin remodeling. Two germline BRM promoter insertion–deletion polymorphisms, BRM-741 and BRM-1321, have been previously associated with an increased risk of lung cancer in smokers and head and neck cancer. To further evaluate their role in cancer susceptibility particularly in early disease, we conducted a preplanned case–control study to investigate the association between the BRM promoter variants and stage I/II upper aerodigestive tract (UADT) cancers (i.e., lung, esophageal, head and neck), a group of early-stage malignancies in which molecular and genetic etiologic factors are poorly understood. The effects of various clinical factors on this association were also studied. We analyzed 562 cases of early-stage UADT cancers and 993 matched healthy controls. The double homozygous BRM promoter variants were associated with a significantly increased risk of early stage UADT cancers (adjusted odds ratio [aOR], 2.46; 95% confidence interval [CI], 1.7–3.8). This association was observed in lung (aOR, 2.61; 95% CI, 1.5–4.9) and head and neck (aOR, 2.75; 95% CI, 1.4–5.6) cancers, but not significantly in esophageal cancer (aOR, 1.66; 95% CI, 0.7–5.8). There was a nonsignificant trend for increased risk in the heterozygotes or single homozygotes. The relationship between the BRM polymorphisms and early-stage UADT cancers was independent of age, sex, smoking status, histology, and clinical stage. These findings suggest that the BRM promoter double insertion homozygotes may be associated with an increased risk of early-stage UADT cancers independent of smoking status and histology, which must be further validated in other populations.
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Affiliation(s)
- Kit Man Wong
- Department of Medical Oncology, Princess Margaret Cancer Center, University of Toronto, Toronto, Ontario, Canada
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31
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Xia QY, Rao Q, Cheng L, Shen Q, Shi SS, Li L, Liu B, Zhang J, Wang YF, Shi QL, Wang JD, Ma HH, Lu ZF, Yu B, Zhang RS, Zhou XJ. Loss of BRM expression is a frequently observed event in poorly differentiated clear cell renal cell carcinoma. Histopathology 2014; 64:847-62. [PMID: 24471421 DOI: 10.1111/his.12334] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 11/19/2013] [Indexed: 01/01/2023]
Affiliation(s)
- Qiu-yuan Xia
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Qiu Rao
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Liang Cheng
- Department of Pathology and Laboratory; Indiana University School of Medicine; Indianapolis IN USA
| | - Qin Shen
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Shan-shan Shi
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Li Li
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Biao Liu
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Jin Zhang
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Yan-fen Wang
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Qun-li Shi
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Jian-dong Wang
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Heng-hui Ma
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Zhen-feng Lu
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Bo Yu
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Ru-song Zhang
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
| | - Xiao-jun Zhou
- Department of Pathology; Nanjing Jinling Hospital; Nanjing University School of Medicine; Nanjing China
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Identifying targets for the restoration and reactivation of BRM. Oncogene 2013; 33:653-64. [PMID: 23524580 DOI: 10.1038/onc.2012.613] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 11/12/2012] [Accepted: 11/14/2012] [Indexed: 12/15/2022]
Abstract
Brahma (BRM) is a novel anticancer gene, which is frequently inactivated in a variety of tumor types. Unlike many anticancer genes, BRM is not mutated, but rather epigenetically silenced. In addition, histone deacetylase complex (HDAC) inhibitors are known to reverse BRM silencing, but they also inactivate it via acetylation of its C-terminus. High-throughput screening has uncovered many compounds that are effective at pharmacologically restoring BRM and thereby inhibit cancer cell growth. As we do not know which specific proteins, if any, regulate BRM, we sought to identify the proteins, which underlie the epigenetic suppression of BRM. By selectively knocking down each HDAC, we found that HDAC3 and HDAC9 regulate BRM expression, whereas HDAC2 controls its acetylation. Similarly, we ectopically overexpressed 21 different histone acetyltransferases and found that KAT6A, KAT6B and KAT7 induce BRM expression, whereas KAT2B and KAT8 induce its acetylation. We also investigated the role of two transcription factors (TFs) linked to either BRM (GATA3) or HDAC9 (MEF2D) expression. Knockdown of either GATA3 and/or MEF2D downregulated HDAC9 and induced BRM. As targets for molecular biotherapy are typically uniquely, or simply differentially expressed in cancer cells, we also determined if any of these proteins are dysregulated. However, by sequencing, no mutations were found in any of these BRM-regulating HDACs, HATs or TFs. We selectively knocked down GATA3, MEF2D, HDAC3 and HDAC9, and found that each gene-specific knockdown induced growth inhibition. We observed that both GATA3 and HDAC9 were greatly overexpressed only in BRM-negative cell lines indicating that HDAC9 may be a good target for therapy. We also found that the mitogen-activated protein (MAP) kinase pathway regulates both BRM acetylation and BRM silencing as MAP kinase pathway inhibitors both induced BRM as well as caused BRM deacetylation. Together, these data identify a cadre of key proteins, which underlie the epigenetic regulation of BRM.
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Wang JR, Gramling SJB, Goldstein DP, Cheng D, Chen D, Azad AK, Tse A, Hon H, Chen Z, Mirshams M, Simpson C, Huang SH, Marquez S, O'Sullivan B, Liu FF, Roberts H, Xu W, Brown DH, Gilbert RW, Gullane PJ, Irish JC, Reisman DN, Liu G. Association of two BRM promoter polymorphisms with head and neck squamous cell carcinoma risk. Carcinogenesis 2013; 34:1012-7. [PMID: 23322154 DOI: 10.1093/carcin/bgt008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The SWI/SNF chromatin remodeling complex is an important regulator of gene expression that has been linked to cancer development. Expression of Brahma (BRM), a critical catalytic subunit of SWI/SNF, is lost in a variety of solid tumors. Two novel BRM promoter polymorphisms (BRM-741 and BRM-1321) have been correlated with BRM loss and elevated cancer risk. The aim(s) of this study were to examine BRM expression in head and neck squamous cell carcinoma (HNSCC) and to correlate BRM polymorphisms with HNSCC risk. BRM expression studies were performed on eight HNSCC cell lines and 76 surgically resected tumor samples. A case-control study was conducted on 668 HNSCC patients (oral cavity, oropharynx, larynx and hypopharynx) and 700 healthy matched controls. BRM expression was lost in 25% of cell lines and 16% of tumors. The homozygous genotype of each polymorphism was significantly associated with increased HNSCC risk [BRM-741: adjusted odds ratio (aOR) 1.75, 95% CI 1.2-2.3, P < 0.001; BRM-1321: aOR 1.65, 95% CI 1.2-2.2, P < 0.001]. Individuals that were homozygous for both BRM polymorphisms had a more than 2-fold increase in the risk of HNSCC (aOR 2.23, 95% CI 1.5-3.4, P < 0.001). A particularly elevated risk was seen within the oropharynx, human papillomavirus-positive subgroup for carriers of both homozygous variants (aOR 3.09, 95% CI 1.5-6.8, P = 0.004). BRM promoter polymorphisms appear to act as susceptibility markers of HNSCC with potential utility in screening, prevention and treatment.
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Affiliation(s)
- Jennifer R Wang
- Department of Otolaryngology-Head and Neck Surgery, University Health Network, Princess Margaret Hospital, Toronto, Ontario M5G 2M9, Canada.
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Liu G, Gramling S, Munoz D, Cheng D, Azad AK, Mirshams M, Chen Z, Xu W, Roberts H, Shepherd FA, Tsao MS, Reisman D. Two novel BRM insertion promoter sequence variants are associated with loss of BRM expression and lung cancer risk. Oncogene 2011; 30:3295-304. [PMID: 21478907 DOI: 10.1038/onc.2011.81] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
SWI/SNF (SWItch/sucrose non-fermentable) complexes are ATP-dependent chromatin remodeling enzymes critically involved in the regulation of multiple functions, including gene expression, differentiation, development, DNA repair, cell adhesion and cell cycle control. BRM, a key SWI/SNF complex subunit, is silenced in 15-20% of many solid tumors. As BRM-deficient mice develop 10-fold more tumors when exposed to carcinogens, BRM is a strong candidate for a cancer susceptibility gene. In this paper, we show that BRM is regulated by transcription, thus demonstrating that the promoter region is important for BRM expression. We sequenced the BRM promoter region, finding two novel promoter indel polymorphisms, BRM -741 and BRM -1321, that are in linkage disequilibrium (D'≥0.83). The variant insertion alleles of both polymorphisms produce sequence variants that are highly homologous to myocyte enhancer factor-2 (MEF2) transcription factor-binding sites; MEF2 is known to recruit histone deacetylases that silence BRM expression. Each polymorphic BRM insertion variant is found in ~20% of Caucasians, and each correlates strongly with the loss of protein expression of BRM, both in cancer cell lines (P=0.009) and in primary human lung tumor specimens (P=0.015). With such strong functional evidence, we conducted a case-control study of 1199 smokers. We found an increased risk of lung cancer when both BRM homozygous promoter insertion variants were present: adjusted odds ratio of 2.19 (95% confidence interval, 1.40-3.43). Thus, we here demonstrate a strong functional association between these polymorphisms and loss of BRM expression. These polymorphisms thus have the potential to identify a sub-population of smokers at greater lung cancer risk, wherein this risk could be driven by an aberrant SWI/SNF chromatin-remodeling pathway.
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Affiliation(s)
- G Liu
- Department of Medicine, Division of Medical Oncology and Hematology, Ontario Cancer Institute, Princess Margaret Hospital-University Health Network, University of Toronto, Toronto, Ontario, Canada
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