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Neguembor MV, Gabellini D. In junk we trust: repetitive DNA, epigenetics and facioscapulohumeral muscular dystrophy. Epigenomics 2012; 2:271-87. [PMID: 22121874 DOI: 10.2217/epi.10.8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant myopathy with a peculiar etiology. Unlike most genetic disorders, FSHD is not caused by mutations in a protein-coding gene. Instead, it is associated with contraction of the D4Z4 macrosatellite repeat array located at 4q35. Interestingly, D4Z4 deletion is not sufficient per se to cause FSHD. Moreover, the disease severity, its rate of progression and the distribution of muscle weakness display great variability even among close family relatives. Hence, additional genetic and epigenetic events appear to be required for FSHD pathogenesis. Indeed, recent findings suggest that virtually all levels of epigenetic regulation, from DNA methylation to higher order chromosomal architecture, exhibit alterations in the disease locus causing deregulation of 4q35 gene expression, ultimately leading to FSHD.
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Affiliation(s)
- Maria V Neguembor
- International PhD Program in Cellular & Molecular Biology, Vita-Salute San Raffaele University, Milan, Italy
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52
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Thiaville MM, Kim J. Oncogenic potential of yin yang 1 mediated through control of imprinted genes. Crit Rev Oncog 2012; 16:199-209. [PMID: 22248054 DOI: 10.1615/critrevoncog.v16.i3-4.40] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The transcription factor Yin Yang (YY) 1 is one of the most evolutionarily well-conserved DNA binding proteins that is ubiquitously expressed among different tissue types. YY1 functions as a critical regulator for a diverse set of genes, making its role in the cancerous environment elusive. Recent studies have demonstrated that clusters of YY1 binding sites are overrepresented in imprinted gene loci. These clustered binding sites may function as a molecular rheostat with respect to YY1 protein levels. YY1 levels were documented to be altered in various tumor tissues in conjunction with the transcriptional levels of the imprinted genes it regulates. This review highlights the unexplored mechanism through which fluctuations in YY1 protein levels alter the transcriptional status of imprinted genes containing clustered YY1 binding sites, which potentially could affect cancer development and/or progression.
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Affiliation(s)
- Michelle M Thiaville
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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53
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Abstract
Yin Yang 1 (YY1) is a transcription factor with diverse and complex biological functions. YY1 either activates or represses gene transcription, depending on the stimuli received by the cells and its association with other cellular factors. Since its discovery, a biological role for YY1 in tumor development and progression has been suggested because of its regulatory activities toward multiple cancer-related proteins and signaling pathways and its overexpression in most cancers. In this review, we primarily focus on YY1 studies in cancer research, including the regulation of YY1 as a transcription factor, its activities independent of its DNA binding ability, the functions of its associated proteins, and mechanisms regulating YY1 expression and activities. We also discuss the correlation of YY1 expression with clinical outcomes of cancer patients and its target potential in cancer therapy. Although there is not a complete consensus about the role of YY1 in cancers based on its activities of regulating oncogene and tumor suppressor expression, most of the currently available evidence supports a proliferative or oncogenic role of YY1 in tumorigenesis.
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Affiliation(s)
- Qiang Zhang
- Department of Cancer Biology and Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA
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Yin Yang-1 suppresses differentiation of hepatocellular carcinoma cells through the downregulation of CCAAT/enhancer-binding protein alpha. J Mol Med (Berl) 2012; 90:1069-77. [PMID: 22391813 DOI: 10.1007/s00109-012-0879-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 01/29/2012] [Accepted: 01/30/2012] [Indexed: 12/15/2022]
Abstract
As a member of the GLI-Kruppel family of transcriptional factors, Yin Yang-1 (YY1) functions as an oncogene in various types of cancers. However, the role of YY1 in hepatocellular carcinogenesis remains unknown. In this report, we investigated the relevance of YY1 to hepatocellular carcinoma (HCC) development. We found that YY1 was upregulated in HCC cell lines. Ectopic YY1 expression promoted the growth of non-tumor liver cells that expressed low level of YY1. In contrast, YY1 depletion inhibited the growth of HCC cells which was accompanied with distinct morphological changes. Moreover, the phenotypic changes induced by YY1 depletion were attributed to cellular differentiation rather than cellular senescence. CCAAT/enhancer-binding protein alpha (CEBPA) which was important to regulate differentiation of hepatocytes was found as the direct target downregulated by YY1. Restoration of CEBPA in YY1-expressing HCC cells induced cellular differentiation and growth inhibition while knockdown of CEBPA expression in non-tumor liver cells promoted cell growth. In summary, our study demonstrated that YY1 could promote hepatocellular carcinogenesis and inhibit cellular differentiation through the downregulation of CEBPA expression.
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The transcription factor C/EBP delta has anti-apoptotic and anti-inflammatory roles in pancreatic beta cells. PLoS One 2012; 7:e31062. [PMID: 22347430 PMCID: PMC3275575 DOI: 10.1371/journal.pone.0031062] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 01/01/2012] [Indexed: 12/31/2022] Open
Abstract
In the course of Type 1 diabetes pro-inflammatory cytokines (e.g., IL-1β, IFN-γ and TNF-α) produced by islet-infiltrating immune cells modify expression of key gene networks in β-cells, leading to local inflammation and β-cell apoptosis. Most known cytokine-induced transcription factors have pro-apoptotic effects, and little is known regarding “protective” transcription factors. To this end, we presently evaluated the role of the transcription factor CCAAT/enhancer binding protein delta (C/EBPδ) on β-cell apoptosis and production of inflammatory mediators in the rat insulinoma INS-1E cells, in purified primary rat β-cells and in human islets. C/EBPδ is expressed and up-regulated in response to the cytokines IL-1β and IFN-γ in rat β-cells and human islets. Small interfering RNA-mediated C/EBPδ silencing exacerbated IL-1β+IFN-γ-induced caspase 9 and 3 cleavage and apoptosis in these cells. C/EBPδ deficiency increased the up-regulation of the transcription factor CHOP in response to cytokines, enhancing expression of the pro-apoptotic Bcl-2 family member BIM. Interfering with C/EBPδ and CHOP or C/EBPδ and BIM in double knockdown approaches abrogated the exacerbating effects of C/EBPδ deficiency on cytokine-induced β-cell apoptosis, while C/EBPδ overexpression inhibited BIM expression and partially protected β-cells against IL-1β+IFN-γ-induced apoptosis. Furthermore, C/EBPδ silencing boosted cytokine-induced production of the chemokines CXCL1, 9, 10 and CCL20 in β-cells by hampering IRF-1 up-regulation and increasing STAT1 activation in response to cytokines. These observations identify a novel function of C/EBPδ as a modulatory transcription factor that inhibits the pro-apoptotic and pro-inflammatory gene networks activated by cytokines in pancreatic β-cells.
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Sarkar TR, Sharan S, Wang J, Pawar SA, Cantwell CA, Johnson PF, Morrison DK, Wang JM, Sterneck E. Identification of a Src tyrosine kinase/SIAH2 E3 ubiquitin ligase pathway that regulates C/EBPδ expression and contributes to transformation of breast tumor cells. Mol Cell Biol 2012; 32:320-32. [PMID: 22037769 PMCID: PMC3255785 DOI: 10.1128/mcb.05790-11] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2011] [Accepted: 10/19/2011] [Indexed: 01/04/2023] Open
Abstract
The transcription factor CCAAT/enhancer-binding protein delta (C/EBPδ, CEBPD) is a tumor suppressor that is downregulated during breast cancer progression but may also promote metastasis. Here, we have investigated the mechanism(s) regulating C/EBPδ expression and its role in human breast cancer cells. We describe a novel pathway by which the tyrosine kinase Src downregulates C/EBPδ through the SIAH2 E3 ubiquitin ligase. Src phosphorylates SIAH2 in vitro and leads to tyrosine phosphorylation and activation of SIAH2 in breast tumor cell lines. SIAH2 interacts with C/EBPδ, but not C/EBPβ, and promotes its polyubiquitination and proteasomal degradation. Src/SIAH2-mediated inhibition of C/EBPδ expression supports elevated cyclin D1 levels, phosphorylation of retinoblastoma protein (Rb), motility, invasive properties, and survival of transformed cells. Pharmacological inhibition of Src family kinases by SKI-606 (bosutinib) induces C/EBPδ expression in an SIAH2-dependent manner, which is necessary for "therapeutic" responses to SKI-606 in vitro. Ectopic expression of degradation-resistant mutants of C/EBPδ, which do not interact with SIAH2 and/or cannot be polyubiquitinated, prevents full transformation of MCF-10A cells by activated Src (Src truncated at amino acid 531 [Src-531]) in vitro. These data reveal that C/EBPδ expression can be regulated at the protein level by oncogenic Src kinase signals through SIAH2, thus contributing to breast epithelial cell transformation.
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Affiliation(s)
- Tapasree Roy Sarkar
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Shikha Sharan
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Jun Wang
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Snehalata A. Pawar
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Carrie A. Cantwell
- Laboratory of Cancer Prevention, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Peter F. Johnson
- Laboratory of Cancer Prevention, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Deborah K. Morrison
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Ju-Ming Wang
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Esta Sterneck
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
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Takeishi K, Shirabe K, Muto J, Toshima T, Taketomi A, Maehara Y. Clinicopathological features and outcomes of young patients with hepatocellular carcinoma after hepatectomy. World J Surg 2011; 35:1063-71. [PMID: 21380583 DOI: 10.1007/s00268-011-1017-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND There are few reports about hepatectomy for young patients with hepatocellular carcinoma (HCC), and the significance of resection for young patients remains unknown. The present study aimed to investigate retrospectively the clinicopathological features and outcomes after hepatectomy of young HCC patients. METHODS Among 610 patients who underwent curative hepatectomy for HCC between January 1987 and December 2007, 13 patients younger than 40 years of age were defined as the young group. Because none of the young group had hepatitis C virus antibodies (HCVAb), 246 patients aged above 40 years without HCVAb were defined as the older group. The clinicopathological findings and outcomes after hepatectomy were compared between the two groups. RESULTS In the young group, 7 patients had hepatitis B surface antigen and 3 other patients had hepatitis B core antibodies. The young group had better liver function but more advanced HCC, with a large tumor size and a high incidence of portal vein invasion compared with the older group. Major hepatectomy was more frequently chosen in the young group than in the older group. There was no significant difference in the incidences of postoperative complications. The overall survival tended to be better in the young group than in the older group (p=0.057). CONCLUSIONS Hepatitis B virus-related HCC was common in the younger group of patients reported here. Although the young patients had advanced HCC, there were no significant differences in the complication rate and the overall survival rate of the young and older groups. Aggressive hepatic resection for young patients would contribute to improved survival and should be recommended.
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Affiliation(s)
- Kazuki Takeishi
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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58
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Wu SR, Li CF, Hung LY, Huang AM, Tseng JT, Tsou JH, Wang JM. CCAAT/enhancer-binding protein delta mediates tumor necrosis factor alpha-induced Aurora kinase C transcription and promotes genomic instability. J Biol Chem 2011; 286:28662-28670. [PMID: 21715338 DOI: 10.1074/jbc.m111.270710] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Epidemiologic and clinical research indicates that chronic inflammation increases the risk of certain cancers, possibly through chromosomal instability. However, the mechanism of inflammation-dependent chromosomal instability associated with tumorigenesis is not well characterized. The transcription factor CCAAT/enhancer-binding protein δ (C/EBPδ, CEBPD) is induced by tumor necrosis factor α (TNFα) and expressed in chronically inflamed tissue. In this study, we show that TNFα promotes aneuploidy. Loss of CEBPD attenuated TNFα-induced aneuploidy, and CEBPD caused centromere abnormality. Additionally, TNFα-induced CEBPD expression augmented anchorage-independent growth. We found that TNFα induced expression of aurora kinase C (AURKC) through CEBPD, and that AURKC also causes aneuploidy. Furthermore, high CEBPD expression correlated with AURKC expression in inflamed cervical tissue specimens. These data provide insight into a novel function for CEBPD in inducing genomic instability through the activation of AURKC expression in response to inflammatory signals.
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Affiliation(s)
- Sin-Rong Wu
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, Tainan 701, Taiwan, Republic of China
| | - Chien-Feng Li
- Department of Pathology, Chi-Mei Medical Center, Tainan 710, Taiwan, Republic of China
| | - Liang-Yi Hung
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, Tainan 701, Taiwan, Republic of China; Molecular Inflammation Research Center, College of Bioscience and Biotechnology, Tainan 701, Taiwan, Republic of China; Infectious Disease and Signaling Research Center, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan, Republic of China
| | - A-Mei Huang
- Department of Medicine, Graduate Institute of Biochemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan, Republic of China
| | - Joseph T Tseng
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, Tainan 701, Taiwan, Republic of China; Molecular Inflammation Research Center, College of Bioscience and Biotechnology, Tainan 701, Taiwan, Republic of China; Infectious Disease and Signaling Research Center, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan, Republic of China
| | - Jen-Hui Tsou
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, Tainan 701, Taiwan, Republic of China
| | - Ju-Ming Wang
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, Tainan 701, Taiwan, Republic of China; Molecular Inflammation Research Center, College of Bioscience and Biotechnology, Tainan 701, Taiwan, Republic of China; Infectious Disease and Signaling Research Center, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan, Republic of China; Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan, Republic of China.
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59
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Balamurugan K, Wang JM, Tsai HH, Sharan S, Anver M, Leighty R, Sterneck E. The tumour suppressor C/EBPδ inhibits FBXW7 expression and promotes mammary tumour metastasis. EMBO J 2010; 29:4106-17. [PMID: 21076392 PMCID: PMC3018791 DOI: 10.1038/emboj.2010.280] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 10/20/2010] [Indexed: 12/22/2022] Open
Abstract
Inflammation and hypoxia are known to promote the metastatic progression of tumours. The CCAAT/enhancer-binding protein-δ (C/EBPδ, CEBPD) is an inflammatory response gene and candidate tumour suppressor, but its physiological role in tumourigenesis in vivo is unknown. Here, we demonstrate a tumour suppressor function of C/EBPδ using transgenic mice overexpressing the Neu/Her2/ERBB2 proto-oncogene in the mammary gland. Unexpectedly, this study also revealed that C/EBPδ is necessary for efficient tumour metastasis. We show that C/EBPδ is induced by hypoxia in tumours in vivo and in breast tumour cells in vitro, and that C/EBPδ-deficient cells exhibit reduced glycolytic metabolism and cell viability under hypoxia. C/EBPδ supports CXCR4 expression. On the other hand, C/EBPδ directly inhibits expression of the tumour suppressor F-box and WD repeat-domain containing 7 gene (FBXW7, FBW7, AGO, Cdc4), encoding an F-box protein that promotes degradation of the mammalian target of rapamycin (mTOR). Consequently, C/EBPδ enhances mTOR/AKT/S6K1 signalling and augments translation and activity of hypoxia-inducible factor-1α (HIF-1α), which is necessary for hypoxia adaptation. This work provides new insight into the mechanisms by which metastasis-promoting signals are induced specifically under hypoxia.
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Affiliation(s)
- Kuppusamy Balamurugan
- Laboratory of Cell and Developmental Signalling, CCR, National Cancer Institute, Frederick, MD, USA
| | - Ju-Ming Wang
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Hsin-Hwa Tsai
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Shikha Sharan
- Laboratory of Cell and Developmental Signalling, CCR, National Cancer Institute, Frederick, MD, USA
| | - Miriam Anver
- Pathology/Histotechnology Laboratory, SAIC-Frederick, National Cancer Institute, Frederick, MD, USA
| | - Robert Leighty
- Data Management Services Inc., National Cancer Institute, Frederick, MD, USA
| | - Esta Sterneck
- Laboratory of Cell and Developmental Signalling, CCR, National Cancer Institute, Frederick, MD, USA
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60
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Cabianca DS, Gabellini D. The cell biology of disease: FSHD: copy number variations on the theme of muscular dystrophy. J Cell Biol 2010; 191:1049-60. [PMID: 21149563 PMCID: PMC3002039 DOI: 10.1083/jcb.201007028] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Accepted: 11/08/2010] [Indexed: 01/17/2023] Open
Abstract
In humans, copy number variations (CNVs) are a common source of phenotypic diversity and disease susceptibility. Facioscapulohumeral muscular dystrophy (FSHD) is an important genetic disease caused by CNVs. It is an autosomal-dominant myopathy caused by a reduction in the copy number of the D4Z4 macrosatellite repeat located at chromosome 4q35. Interestingly, the reduction of D4Z4 copy number is not sufficient by itself to cause FSHD. A number of epigenetic events appear to affect the severity of the disease, its rate of progression, and the distribution of muscle weakness. Indeed, recent findings suggest that virtually all levels of epigenetic regulation, from DNA methylation to higher order chromosomal architecture, are altered at the disease locus, causing the de-regulation of 4q35 gene expression and ultimately FSHD.
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Affiliation(s)
- Daphne Selvaggia Cabianca
- International PhD Program in Cellular and Molecular Biology, Vita-Salute San Raffaele University, 20132 Milan, Italy
- Division of Regenerative Medicine, San Raffaele Scientific Institute, DIBIT 1, 2A3-49, 20132 Milan, Italy
| | - Davide Gabellini
- Division of Regenerative Medicine, San Raffaele Scientific Institute, DIBIT 1, 2A3-49, 20132 Milan, Italy
- Dulbecco Telethon Institute, 20132 Milan, Italy
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61
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Mendenhall EM, Koche RP, Truong T, Zhou VW, Issac B, Chi AS, Ku M, Bernstein BE. GC-rich sequence elements recruit PRC2 in mammalian ES cells. PLoS Genet 2010; 6:e1001244. [PMID: 21170310 PMCID: PMC3000368 DOI: 10.1371/journal.pgen.1001244] [Citation(s) in RCA: 326] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Accepted: 11/09/2010] [Indexed: 11/22/2022] Open
Abstract
Polycomb proteins are epigenetic regulators that localize to developmental loci in the early embryo where they mediate lineage-specific gene repression. In Drosophila, these repressors are recruited to sequence elements by DNA binding proteins associated with Polycomb repressive complex 2 (PRC2). However, the sequences that recruit PRC2 in mammalian cells have remained obscure. To address this, we integrated a series of engineered bacterial artificial chromosomes into embryonic stem (ES) cells and examined their chromatin. We found that a 44 kb region corresponding to the Zfpm2 locus initiates de novo recruitment of PRC2. We then pinpointed a CpG island within this locus as both necessary and sufficient for PRC2 recruitment. Based on this causal demonstration and prior genomic analyses, we hypothesized that large GC-rich elements depleted of activating transcription factor motifs mediate PRC2 recruitment in mammals. We validated this model in two ways. First, we showed that a constitutively active CpG island is able to recruit PRC2 after excision of a cluster of activating motifs. Second, we showed that two 1 kb sequence intervals from the Escherichia coli genome with GC-contents comparable to a mammalian CpG island are both capable of recruiting PRC2 when integrated into the ES cell genome. Our findings demonstrate a causal role for GC-rich sequences in PRC2 recruitment and implicate a specific subset of CpG islands depleted of activating motifs as instrumental for the initial localization of this key regulator in mammalian genomes. Key developmental genes are precisely turned on or off during development, thus creating a complex, multi-tissue embryo. The mechanism that keeps genes off, or repressed, is crucial to proper development. In embryonic stem cells, Polycomb repressive complex 2 (PRC2) is recruited to the promoters of these developmental genes and helps to maintain repression in the appropriate tissues through development. How PRC2 is initially recruited to these genes in the early embryo remains elusive. Here we experimentally demonstrate that stretches of GC-rich DNA, termed CpG islands, can initiate recruitment of PRC2 in embryonic stem cells when they are transcriptionally-inactive. Surprisingly, we find that GC-rich DNA from bacterial genomes can also initiate recruitment of PRC2 in embryonic stem cells. This supports a model where inactive GC-rich DNA can itself suffice to recruit PRC2 even in the absence of more complex DNA sequence motifs.
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Affiliation(s)
- Eric M. Mendenhall
- Howard Hughes Medical Institute and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Systems Biology and Center for Cancer Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Richard P. Koche
- Howard Hughes Medical Institute and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Systems Biology and Center for Cancer Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Thanh Truong
- Howard Hughes Medical Institute and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Systems Biology and Center for Cancer Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Vicky W. Zhou
- Howard Hughes Medical Institute and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Systems Biology and Center for Cancer Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Biological and Biomedical Sciences, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Biju Issac
- Howard Hughes Medical Institute and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Systems Biology and Center for Cancer Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Andrew S. Chi
- Howard Hughes Medical Institute and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Systems Biology and Center for Cancer Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Neuro-Oncology Division, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Manching Ku
- Howard Hughes Medical Institute and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Systems Biology and Center for Cancer Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Bradley E. Bernstein
- Howard Hughes Medical Institute and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Systems Biology and Center for Cancer Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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Chen H, Libertini SJ, George M, Dandekar S, Tepper CG, Al-Bataina B, Kung HJ, Ghosh PM, Mudryj M. Genome-wide analysis of androgen receptor binding and gene regulation in two CWR22-derived prostate cancer cell lines. Endocr Relat Cancer 2010; 17:857-73. [PMID: 20634343 PMCID: PMC3539310 DOI: 10.1677/erc-10-0081] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Prostate carcinoma (CaP) is a heterogeneous multifocal disease where gene expression and regulation are altered not only with disease progression but also between metastatic lesions. The androgen receptor (AR) regulates the growth of metastatic CaPs; however, sensitivity to androgen ablation is short lived, yielding to emergence of castrate-resistant CaP (CRCaP). CRCaP prostate cancers continue to express the AR, a pivotal prostate regulator, but it is not known whether the AR targets similar or different genes in different castrate-resistant cells. In this study, we investigated AR binding and AR-dependent transcription in two related castrate-resistant cell lines derived from androgen-dependent CWR22-relapsed tumors: CWR22Rv1 (Rv1) and CWR-R1 (R1). Expression microarray analysis revealed that R1 and Rv1 cells had significantly different gene expression profiles individually and in response to androgen. In contrast, AR chromatin immunoprecipitation (ChIP) combined with promoter DNA microarrays (ChIP-on-chip) studies showed that they have a similar AR-binding profile. Coupling of the microarray study with ChIP-on-chip analysis identified direct AR targets. The most prominent function of transcripts that were direct AR targets was transcriptional regulation, although only one transcriptional regulator, CCAAT/enhancer binding protein δ, was commonly regulated in both lines. Our results indicate that the AR regulates the expression of different transcripts in the two lines, and demonstrate the versatility of the AR-regulated gene expression program in prostate tumors.
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Affiliation(s)
- Honglin Chen
- Department of Medical Microbiology and Immunology, University of California Davis, Davis, California 95616, USA
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63
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Pan YC, Li CF, Ko CY, Pan MH, Chen PJ, Tseng JT, Wu WC, Chang WC, Huang AM, Sterneck E, Wang JM. CEBPD reverses RB/E2F1-mediated gene repression and participates in HMDB-induced apoptosis of cancer cells. Clin Cancer Res 2010; 16:5770-80. [PMID: 20971808 DOI: 10.1158/1078-0432.ccr-10-1025] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE Recent evidence indicates that a tumor suppressor gene CEBPD (CCAAT/enhancer-binding protein delta) is downregulated in many cancers including cervical cancer, which provides a therapeutic potential associated with its reactivation. However, little is known for CEBPD activators and the effect of reactivation of CEBPD transcription upon anticancer drug treatment. In this study, we identified a novel CEBPD activator, 1-(2-hydroxy-5-methylphenyl)-3-phenyl-1,3-propanedione (HMDB). The purpose of this study is to characterize the mechanism of HMDB-induced CEBPD activation and its potential effect in cancer therapy. EXPERIMENTAL DESIGN Methylation-specific PCR assay, reporter assay, and chromatin immunoprecipitation (ChIP) assay were performed to dissect the signaling pathway of HMDB-induced CEBPD transcription. Furthermore, a consequence of HMDB-induced CEBPD expression was linked with E2F1 and retinoblastoma (RB), which discloses the scenario of CEBPD, E2F1, and RB bindings and transcriptional regulation on the promoters of proapoptotic genes, PPARG2 and GADD153. Finally, the anticancer effect of HMDB was examined in xenograft mice. RESULTS We demonstrate that CEBPD plays an essential role in HMDB-mediated apoptosis of cancer cells. HMDB up-regulates CEBPD transcription through the p38/CREB pathway, thus leading to transcriptional activation of PPARG2 and GADD153. Furthermore, increased level of CEBPD attenuates E2F1-induced cancer cell proliferation and partially rescues RB/E2F1-mediated repression of PPARG2 and GADD153 transcription. Moreover, HMDB treatment attenuates the growth of A431 xenografts in severe combined immunodeficient mice mice. CONCLUSIONS These results clearly demonstrate that HMDB kills cancer cells through activation of CEBPD pathways and suggest that HMDB can serve as a superior chemotherapeutic agent with limited potential for adverse side effects.
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Affiliation(s)
- Yen-Chun Pan
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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Wang J, Sarkar TR, Zhou M, Sharan S, Ritt DA, Veenstra TD, Morrison DK, Huang AM, Sterneck E. CCAAT/enhancer binding protein delta (C/EBPdelta, CEBPD)-mediated nuclear import of FANCD2 by IPO4 augments cellular response to DNA damage. Proc Natl Acad Sci U S A 2010; 107:16131-6. [PMID: 20805509 PMCID: PMC2941265 DOI: 10.1073/pnas.1002603107] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Maintenance of genomic integrity is an essential cellular function. We previously reported that the transcription factor and tumor suppressor CCAAT/enhancer binding protein δ (C/EBPδ, CEBPD; also known as "NFIL-6β") promotes genomic stability. However, the molecular mechanism was not known. Here, we show that C/EBPδ is a DNA damage-induced gene, which supports survival of mouse bone marrow cells, mouse embryo fibroblasts (MEF), human fibroblasts, and breast tumor cells in response to the DNA cross-linking agent mitomycin C (MMC). Using gene knockout, protein depletion, and overexpression studies, we found that C/EBPδ promotes monoubiquitination of the Fanconi anemia complementation group D2 protein (FANCD2), which is necessary for its function in replication-associated DNA repair. C/EBPδ interacts with FANCD2 and importin 4 (IPO4, also known as "Imp4" and "RanBP4") via separate domains, mediating FANCD2-IPO4 association and augmenting nuclear import of FANCD2, a prerequisite for its monoubiquitination. This study identifies a transcription-independent activity of C/EBPδ in the DNA damage response that may in part underlie its tumor suppressor function. Furthermore, we report a function of IPO4 and nuclear import in the Fanconi anemia pathway of DNA repair.
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Affiliation(s)
- Jun Wang
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702; and
| | - Tapasree Roy Sarkar
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702; and
| | - Ming Zhou
- Laboratory of Proteomics and Analytical Technologies, Advanced Technology Program, SAIC-Frederick, Frederick, MD, 21702
| | - Shikha Sharan
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702; and
| | - Daniel A. Ritt
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702; and
| | - Timothy D. Veenstra
- Laboratory of Proteomics and Analytical Technologies, Advanced Technology Program, SAIC-Frederick, Frederick, MD, 21702
| | - Deborah K. Morrison
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702; and
| | - A-Mei Huang
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702; and
| | - Esta Sterneck
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702; and
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65
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Huang THM, Esteller M. Chromatin remodeling in mammary gland differentiation and breast tumorigenesis. Cold Spring Harb Perspect Biol 2010; 2:a004515. [PMID: 20610549 DOI: 10.1101/cshperspect.a004515] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
DNA methylation and histone modifications have essential roles in remodeling chromatin structure of genes necessary for multi-lineage differentiation of mammary stem/progenitor cells. The role of this well-defined epigenetic programming is to heritably maintain transcriptional plasticity of these loci over multiple cell divisions in the differentiated progeny. Epigenetic events can be deregulated in progenitor cells chronically exposed to xenoestrogen or inflammatory microenvironment. In addition, epigenetically mediated silencing of genes associated with tumor suppression can take place, resulting in clonal proliferation of undifferentiated or semidifferentiated cells. Alternatively, microRNAs that negatively regulate the expression of their protein-coding targets may become epigenetically repressed, leading to oncogenic expression of these genes. Here we further discuss interactions between DNA methylation and histone modifications that have significant contributions to the differentiation of mammary stem/progenitor cells and to tumor initiation and progression.
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Affiliation(s)
- Tim H-M Huang
- Human Cancer Genetics Program, Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, Ohio 43220, USA.
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66
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Lee SH, Cho SY, Shannon MF, Fan J, Rangasamy D. The impact of CpG island on defining transcriptional activation of the mouse L1 retrotransposable elements. PLoS One 2010; 5:e11353. [PMID: 20613872 PMCID: PMC2894050 DOI: 10.1371/journal.pone.0011353] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 05/20/2010] [Indexed: 12/31/2022] Open
Abstract
Background L1 retrotransposable elements are potent insertional mutagens responsible for the generation of genomic variation and diversification of mammalian genomes, but reliable estimates of the numbers of actively transposing L1 elements are mostly nonexistent. While the human and mouse genomes contain comparable numbers of L1 elements, several phylogenetic and L1Xplore analyses in the mouse genome suggest that 1,500–3,000 active L1 elements currently exist and that they are still expanding in the genome. Conversely, the human genome contains only 150 active L1 elements. In addition, there is a discrepancy among the nature and number of mouse L1 elements in L1Xplore and the mouse genome browser at the UCSC and in the literature. To date, the reason why a high copy number of active L1 elements exist in the mouse genome but not in the human genome is unknown, as are the potential mechanisms that are responsible for transcriptional activation of mouse L1 elements. Methodology/Principal Findings We analyzed the promoter sequences of the 1,501 potentially active mouse L1 elements retrieved from the GenBank and L1Xplore databases and evaluated their transcription factors binding sites and CpG content. To this end, we found that a substantial number of mouse L1 elements contain altered transcription factor YY1 binding sites on their promoter sequences that are required for transcriptional initiation, suggesting that only a half of L1 elements are capable of being transcriptionally active. Furthermore, we present experimental evidence that previously unreported CpG islands exist in the promoters of the most active TF family of mouse L1 elements. The presence of sequence variations and polymorphisms in CpG islands of L1 promoters that arise from transition mutations indicates that CpG methylation could play a significant role in determining the activity of L1 elements in the mouse genome. Conclusions A comprehensive analysis of mouse L1 promoters suggests that the number of transcriptionally active elements is significantly lower than the total number of full-length copies from the three active mouse L1 families. Like human L1 elements, the CpG islands and potentially the transcription factor YY1 binding sites are likely to be required for transcriptional initiation of mouse L1 elements.
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Affiliation(s)
- Sung-Hun Lee
- The John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Soo-Young Cho
- Division of Molecular and Life Sciences, Hanyang University, Ansan, Republic of Korea
| | - M. Frances Shannon
- The John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Jun Fan
- The John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Danny Rangasamy
- The John Curtin School of Medical Research, Australian National University, Canberra, Australia
- * E-mail:
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Pawar SA, Sarkar TR, Balamurugan K, Sharan S, Wang J, Zhang Y, Dowdy SF, Huang AM, Sterneck E. C/EBP{delta} targets cyclin D1 for proteasome-mediated degradation via induction of CDC27/APC3 expression. Proc Natl Acad Sci U S A 2010; 107:9210-5. [PMID: 20439707 PMCID: PMC2889124 DOI: 10.1073/pnas.0913813107] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The transcription factor CCAAT/enhancer binding protein delta (C/EBPdelta, CEBPD, NFIL-6beta) has tumor suppressor function; however, the molecular mechanism(s) by which C/EBPdelta exerts its effect are largely unknown. Here, we report that C/EBPdelta induces expression of the Cdc27 (APC3) subunit of the anaphase promoting complex/cyclosome (APC/C), which results in the polyubiquitination and degradation of the prooncogenic cell cycle regulator cyclin D1, and also down-regulates cyclin B1, Skp2, and Plk-1. In C/EBPdelta knockout mouse embryo fibroblasts (MEF) Cdc27 levels were reduced, whereas cyclin D1 levels were increased even in the presence of activated GSK-3beta. Silencing of C/EBPdelta, Cdc27, or the APC/C coactivator Cdh1 (FZR1) in MCF-10A breast epithelial cells increased cyclin D1 protein expression. Like C/EBPdelta, and in contrast to cyclin D1, Cdc27 was down-regulated in several breast cancer cell lines, suggesting that Cdc27 itself may be a tumor suppressor. Cyclin D1 is a known substrate of polyubiquitination complex SKP1/CUL1/F-box (SCF), and our studies show that Cdc27 directs cyclin D1 to alternative degradation by APC/C. These findings shed light on the role and regulation of APC/C, which is critical for most cellular processes.
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Affiliation(s)
- Snehalata A. Pawar
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201; and
| | - Tapasree Roy Sarkar
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201; and
| | - Kuppusamy Balamurugan
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201; and
| | - Shikha Sharan
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201; and
| | - Jun Wang
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201; and
| | - Youhong Zhang
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201; and
| | - Steven F. Dowdy
- Department of Cellular and Molecular Medicine, Howard Hughes Medical Institute, University of California, San Diego School of Medicine, La Jolla, CA 92093-0686
| | - A-Mei Huang
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201; and
| | - Esta Sterneck
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201; and
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Si J, Yu X, Zhang Y, DeWille JW. Myc interacts with Max and Miz1 to repress C/EBPdelta promoter activity and gene expression. Mol Cancer 2010; 9:92. [PMID: 20426839 PMCID: PMC2879254 DOI: 10.1186/1476-4598-9-92] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Accepted: 04/28/2010] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND "Loss of function" alterations in CCAAT/Enhancer Binding Proteindelta (C/EBPdelta) have been reported in a number of human cancers including breast, prostate and cervical cancer, hepatocellular carcinoma and acute myeloid leukemia. C/EBPdelta gene transcription is induced during cellular quiescence and repressed during active cell cycle progression. C/EBPdelta exhibits tumor suppressor gene properties including reduced expression in cancer cell lines and tumors and promoter methylation silencing. We previously reported that C/EBPdelta expression is inversely correlated with c-Myc (Myc) expression. Aberrant Myc expression is common in cancer and transcriptional repression is a major mechanism of Myc oncogenesis. A number of tumor suppressor genes are targets of Myc transcriptional repression including C/EBPalpha, p15INK4, p21CIP1, p27KIP1 and p57KIP2. This study investigated the mechanisms underlying Myc repression of C/EBPdelta expression. RESULTS Myc represses C/EBPdelta promoter activity in nontransformed mammary epithelial cells in a dose-dependent manner that requires Myc Box II, Basic Region and HLH/LZ domains. Chromatin Immunoprecipitation (ChIP) assays demonstrate that Myc, Miz1 and Max are associated with the C/EBPdelta promoter in proliferating cells, when C/EBPdelta expression is repressed. EMSAs demonstrate that Miz1 binds to a 30 bp region (-100 to -70) of the C/EBPdelta promoter which contains a putative transcription initiator (Inr) element. Miz1 functions exclusively as a repressor of C/EBPdelta promoter activity. Miz1 siRNA expression or expression of a Miz1 binding deficient Myc (MycV394D) construct reduces Myc repression of C/EBPdelta promoter activity. Max siRNA expression, or expression of a Myc construct lacking the HLH/LZ (Max interacting) region, also reduces Myc repression of C/EBPdelta promoter activity. Miz1 and Max siRNA treatments attenuate Myc repression of endogenous C/EBPdelta expression. Myc Box II interacting proteins RuvBl1 (Pontin, TIP49) and RuvBl2 (Reptin, TIP48) enhances Myc repression of C/EBPdelta promoter activity. CONCLUSION Myc represses C/EBPdelta expression by associating with the C/EBPdelta proximal promoter as a transient component of a repressive complex that includes Max and Miz1. RuvBl1 and RuvBl2 enhance Myc repression of C/EBPdelta promoter activity. These results identify protein interactions that mediate Myc repression of C/EBPdelta, and possibly other tumor suppressor genes, and suggest new therapeutic targets to block Myc transcriptional repression and oncogenic function.
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Affiliation(s)
- Junling Si
- Department of Veterinary Biosciences, Ohio State University College of Veterinary Medicine, Columbus, Ohio 43210, USA
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69
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Hour TC, Lai YL, Kuan CI, Chou CK, Wang JM, Tu HY, Hu HT, Lin CS, Wu WJ, Pu YS, Sterneck E, Huang AM. Transcriptional up-regulation of SOD1 by CEBPD: a potential target for cisplatin resistant human urothelial carcinoma cells. Biochem Pharmacol 2010; 80:325-34. [PMID: 20385105 DOI: 10.1016/j.bcp.2010.04.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2010] [Revised: 04/02/2010] [Accepted: 04/05/2010] [Indexed: 02/04/2023]
Abstract
Bladder cancer is the fourth most common type of cancer in men (ninth in women) in the United States. Cisplatin is an effective agent against the most common subtype, urothelial carcinoma. However, the development of chemotherapy resistance is a severe clinical problem for the successful treatment of this and other cancers. A better understanding of the cellular and molecular events in response to cisplatin treatment and the development of resistance are critical to improve the therapeutic options for patients. Here, we report that expression of the CCAAT/enhancer binding protein delta (CEBPD, C/EBPdelta, NF-IL6beta) is induced by cisplatin in the human bladder urothelial carcinoma NTUB1 cell line and is specifically elevated in a cisplatin resistant subline. Expression of CEBPD reduced cisplatin-induced reactive oxygen species (ROS) and apoptosis in NTUB1 cells by inducing the expression of Cu/Zn-superoxide dismutase (SOD1) via direct promoter transactivation. Several reports have implicated CEBPD as a tumor suppressor gene. This study reveals a novel role for CEBPD in conferring drug resistance, suggesting that it can also be pro-oncogenic. Furthermore, our data suggest that SOD inhibitors, which are already used as anti-angiogenic agents, may be suitable for combinatorial chemotherapy to prevent or treat cisplatin resistance in bladder and possibly other cancers.
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Affiliation(s)
- Tzyh-Chyuan Hour
- Department of Medicine, Graduate Institute of Biochemistry, Kaohsiung Medical University, Kaohsiung, Taiwan
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Lin LF, Chuang CH, Li CF, Liao CC, Cheng CP, Cheng TL, Shen MR, Tseng JT, Chang WC, Lee WH, Wang JM. ZBRK1 acts as a metastatic suppressor by directly regulating MMP9 in cervical cancer. Cancer Res 2009; 70:192-201. [PMID: 19996286 DOI: 10.1158/0008-5472.can-09-2641] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The BRCA1-interacted transcriptional repressor ZBRK1 has been associated with antiangiogenesis, but direct evidence of a tumor suppressor role has been lacking. In this study, we provide evidence of such a role in cervical carcinoma. ZBRK1 levels in cervical tumor cells were significantly lower than in normal cervical epithelial cells. In HeLa cervical cancer cells, enforced expression inhibited malignant growth, invasion, and metastasis in a variety of in vitro and in vivo assays. Expression of the metalloproteinase MMP9, which is known to be an important driver of invasion and metastasis, was found to be inversely correlated with ZBRK1 in tumor tissues and a target for repression in tumor cells. Our findings suggest that ZBRK1 acts to inhibit metastasis of cervical carcinoma, perhaps by modulating MMP9 expression.
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Affiliation(s)
- Li-Fang Lin
- Institute of Basic Medical Sciences, National Cheng Kung University, Department of Pathology, Tainan, Taiwan
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Mirghomizadeh F, Bullwinkel J, Orinska Z, Janssen O, Petersen A, Singh PB, Bulfone-Paus S. Transcriptional regulation of mouse mast cell protease-2 by interleukin-15. J Biol Chem 2009; 284:32635-41. [PMID: 19801677 DOI: 10.1074/jbc.m109.015446] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Mast cells (MCs) play a critical role in innate and adaptive immunity through the release of cytokines, chemokines, lipid mediators, biogenic amines, and proteases. We recently showed that the activities of MC proteases are transcriptionally regulated by intracellularly retained interleukin-15 (IL-15), and we provided evidence that this cytokine acts as a specific regulator of mouse mast cell protease-2 (mMCP-2). Here, we show that in wild-type bone marrow-derived mast cells (BMMCs) IL-15 inhibits mMCP-2 transcription indirectly by inducing differential expression and mMCP-2 promoter binding of the bifunctional transcription factors C/EBPbeta and YY1. In wild-type BMMCs, C/EBPbeta expression predominates over YY1 expression, and thus C/EBPbeta preferentially binds to the mMCP-2 promoter. In IL-15-deficient BMMCs, the opposite is found: YY1 expression predominates and binds to the mMCP-2 promoter at the expense of C/EBPbeta. Hypertranscription of the mMCP-2 gene in IL-15-deficient BMMCs is associated with histone acetylation and, intriguingly, with methylation of non-CpG dinucleotides within the MCP-2 promoter. This suggests a novel model of cytokine-controlled protease transcription: non-CpG methylation maintains a chromosomal domain in an "open" configuration that is permissive for gene expression.
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Affiliation(s)
- Farhad Mirghomizadeh
- Division of Immunobiology, Department of Immunology and Cell Biology, Research Center Borstel, 23845 Borstel, Germany
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Rizkallah R, Hurt MM. Regulation of the transcription factor YY1 in mitosis through phosphorylation of its DNA-binding domain. Mol Biol Cell 2009; 20:4766-76. [PMID: 19793915 DOI: 10.1091/mbc.e09-04-0264] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Yin-Yang 1 (YY1) is a ubiquitously expressed zinc finger transcription factor. It regulates a vast array of genes playing critical roles in development, differentiation, and cell cycle. Very little is known about the mechanisms that regulate the functions of YY1. It has long been proposed that YY1 is a phosphoprotein; however, a direct link between phosphorylation and the function of YY1 has never been proven. Investigation of the localization of YY1 during mitosis shows that it is distributed to the cytoplasm during prophase and remains excluded from DNA until early telophase. Immunostaining studies show that YY1 is distributed equally between daughter cells and rapidly associates with decondensing chromosomes in telophase, suggesting a role for YY1 in early marking of active and repressed genes. The exclusion of YY1 from DNA in prometaphase HeLa cells correlated with an increase in the phosphorylation of YY1 and loss of DNA-binding activity that can be reversed by dephosphorylation. We have mapped three phosphorylation sites on YY1 during mitosis and show that phosphorylation of two of these sites can abolish the DNA-binding activity of YY1. These results demonstrate a novel mechanism for the inactivation of YY1 through phosphorylation of its DNA-binding domain.
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Affiliation(s)
- Raed Rizkallah
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306-4300, USA
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