The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Paul R Jamieson - One of the best experts on this subject based on the ideXlab platform.
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canonical prc2 function is essential for mammary gland development and affects chromatin compaction in mammary organoids
PLOS Biology, 2018Co-Authors: Ewa M Michalak, Michael J G Milevskiy, Rachel M Joyce, Johanna F Dekkers, Paul R JamiesonAbstract:Distinct transcriptional states are maintained through organization of chromatin, resulting from the sum of numerous repressive and active histone modifications, into tightly packaged heterochromatin versus more accessible euchromatin. Polycomb repressive complex 2 (PRC2) is the main mammalian complex responsible for histone 3 lysine 27 trimethylation (H3K27me3) and is integral to chromatin organization. Using in vitro and in vivo studies, we show that deletion of SUZ12, a core component of all PRC2 complexes, results in loss of H3K27me3 and H3K27me2 dimethylation (H3K27me2), completely blocks normal mammary gland development, and profoundly curtails progenitor activity in 3D organoid cultures. Through the application of mammary organoids to bypass the severe phenotype associated with SUZ12 loss in vivo, we have explored gene expression and chromatin structure in wild-type and SUZ12-deleted basal-derived organoids. Analysis of organoids led to the identification of lineage-specific changes in gene expression and chromatin structure, inferring cell type–specific PRC2-mediated gene silencing of the chromatin state. These expression changes were accompanied by cell cycle arrest but not lineage infidelity. Together, these data indicate that canonical PRC2 function is essential for development of the mammary gland through the repression of alternate transcription programs and maintenance of chromatin states.
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canonical prc2 function is essential for mammary gland development and affects chromatin compaction in mammary organoids
PLOS Biology, 2018Co-Authors: Ewa M Michalak, Michael J G Milevskiy, Johanna F Dekkers, Paul R Jamieson, Rachel JoyceAbstract:Distinct transcriptional states are maintained through organization of chromatin, resulting from the sum of numerous repressive and active histone modifications, into tightly packaged heterochromatin versus more accessible euchromatin. Polycomb repressive complex 2 (PRC2) is the main mammalian complex responsible for histone 3 lysine 27 trimethylation (H3K27me3) and is integral to chromatin organization. Using in vitro and in vivo studies, we show that deletion of SUZ12, a core component of all PRC2 complexes, results in loss of H3K27me3 and H3K27 dimethylation (H3K27me2), completely blocks normal mammary gland development, and profoundly curtails progenitor activity in 3D organoid cultures. Through the application of mammary organoids to bypass the severe phenotype associated with SUZ12 loss in vivo, we have explored gene expression and chromatin structure in wild-type and SUZ12-deleted basal-derived organoids. Analysis of organoids led to the identification of lineage-specific changes in gene expression and chromatin structure, inferring cell type-specific PRC2-mediated gene silencing of the chromatin state. These expression changes were accompanied by cell cycle arrest but not lineage infidelity. Together, these data indicate that canonical PRC2 function is essential for development of the mammary gland through the repression of alternate transcription programs and maintenance of chromatin states.
Ourania M Andrisani - One of the best experts on this subject based on the ideXlab platform.
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rna helicase dead box protein 5 regulates polycomb repressive complex 2 hox transcript antisense intergenic rna function in hepatitis b virus infection and hepatocarcinogenesis
Hepatology, 2016Co-Authors: Hao Zhang, Philippe Merle, Elizabeth J. Tran, Zheng Xing, Saravana Kumar Kailasam Mani, Brigitte Bancel, David Durantel, Fabien Zoulim, Ourania M AndrisaniAbstract:Chronic hepatitis B virus (HBV) infection is a major factor in hepatocellular carcinoma (HCC) pathogenesis by a mechanism not yet understood. Elucidating mechanisms of HBV-mediated hepatocarcinogenesis is needed to gain insights into classification and treatment of HCC. In HBV replicating cells, including virus-associated HCCs, suppressor of zeste 12 homolog (SUZ12), a core subunit of Polycomb repressive complex2 (PRC2), undergoes proteasomal degradation. This process requires the long noncoding RNA, Hox transcript antisense intergenic RNA (HOTAIR). Intriguingly, HOTAIR interacts with PRC2 and also binds RNA-binding E3 ligases, serving as a ubiquitination scaffold. Herein, we identified the RNA helicase, DEAD box protein 5 (DDX5), as a regulator of SUZ12 stability and PRC2-mediated gene repression, acting by regulating RNA-protein complexes formed with HOTAIR. Specifically, knockdown of DDX5 and/or HOTAIR enabled reexpression of PRC2-repressed genes epithelial cell adhesion molecule (EpCAM) and pluripotency genes. Also, knockdown of DDX5 enhanced transcription from the HBV minichromosome. The helicase activity of DDX5 stabilized SUZ12- and PRC2-mediated gene silencing, by displacing the RNA-binding E3 ligase, Mex-3 RNA-binding family member B (Mex3b), from HOTAIR. Conversely, ectopic expression of Mex3b ubiquitinated SUZ12, displaced DDX5 from HOTAIR, and induced SUZ12 down-regulation. In G2 phase of cells expressing the HBV X protein (HBx), SUZ12 preferentially associated with Mex3b, but not DDX5, resulting in de-repression of PRC2 targets, including EpCAM and pluripotency genes. Significantly, liver tumors from HBx/c-myc bitransgenic mice and chronically HBV-infected patients exhibited a strong negative correlation between DDX5 messenger RNA levels, pluripotency gene expression, and liver tumor differentiation. Notably, chronically infected HBV patients with HCC expressing reduced DDX5 exhibited poor prognosis after tumor resection, identifying DDX5 as an important player in poor prognosis HCC. Conclusion: The RNA helicase DDX5, and E3 ligase Mex3b, are important cellular targets for the design of novel, epigenetic therapies to combat HBV infection and poor prognosis HBV-associated liver cancer. (Hepatology 2016;64:1033-1048)
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plk1 and hotair accelerate proteasomal degradation of SUZ12 and znf198 during hepatitis b virus induced liver carcinogenesis
Cancer Research, 2015Co-Authors: Hao Zhang, Ronald L Hullinger, Philippe Merle, Saravana Kumar Kailasam Mani, Ahmed Diab, Huitao Fan, Ourania M AndrisaniAbstract:Elucidating mechanisms of hepatitis B virus (HBV)-mediated hepatocarcinogenesis is needed to gain insights into the etiology and treatment of liver cancer. Cells where HBV is replicating exhibit increased expression of Plk1 kinase and reduced levels of two transcription repression factors, SUZ12 and ZNF198. SUZ12 is an essential subunit of the transcription repressive complex PRC2. ZNF198 stabilizes the transcription repressive complex composed of LSD1, Co-REST, and HDAC1. These two transcription repressive complexes are held together by binding the long noncoding RNA HOTAIR. In this study, we linked these regulatory events mechanistically by showing that Plk1 induces proteasomal degradation of SUZ12 and ZNF198 by site-specific phosphorylation. Plk1-dependent ubiquitination of SUZ12 and ZNF198 was enhanced by expression of HOTAIR, significantly reducing SUZ12 and ZNF198 stability. In cells expressing the HBV X protein (HBx), downregulation of SUZ12 and ZNF198 mediated global changes in histone modifications. In turn, HBx-expressing cells propagated an altered chromatin landscape after cell division, as exemplified by changes in histone modifications of the EpCAM promoter, a target of PRC2 and LSD1/Co-REST/HDAC1 complexes. Notably, liver tumors from X/c-myc bitransgenic mice exhibited downregulation of SUZ12 and ZNF198 along with elevated expression of Plk1, HOTAIR, and EpCAM. Clinically, similar effects were documented in a set of HBV-related liver tumors consistent with the likelihood that downregulation of SUZ12 and ZNF198 leads to epigenetic reprogramming of infected hepatocytes. Because both Plk1 and HOTAIR are elevated in many human cancers, we propose that their combined effects are involved in epigenetic reprogramming associated broadly with oncogenic transformation.
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plk1 and hotair accelerate proteasomal degradation of SUZ12 and znf198 during hepatitis b virus induced liver carcinogenesis
Cancer Research, 2015Co-Authors: Hao Zhang, Ronald L Hullinger, Philippe Merle, Saravana Kumar Kailasam Mani, Ahmed Diab, Ourania M AndrisaniAbstract:Elucidating mechanisms of hepatitis B virus (HBV)–mediated hepatocarcinogenesis is needed to gain insights into the etiology and treatment of liver cancer. Cells where HBV is replicating exhibit increased expression of Plk1 kinase and reduced levels of two transcription repression factors, SUZ12 and ZNF198. SUZ12 is an essential subunit of the transcription repressive complex PRC2. ZNF198 stabilizes the transcription repressive complex composed of LSD1, Co-REST, and HDAC1. These two transcription repressive complexes are held together by binding the long noncoding RNA HOTAIR. In this study, we linked these regulatory events mechanistically by showing that Plk1 induces proteasomal degradation of SUZ12 and ZNF198 by site-specific phosphorylation. Plk1-dependent ubiquitination of SUZ12 and ZNF198 was enhanced by expression of HOTAIR, significantly reducing SUZ12 and ZNF198 stability. In cells expressing the HBV X protein (HBx), downregulation of SUZ12 and ZNF198 mediated global changes in histone modifications. In turn, HBx-expressing cells propagated an altered chromatin landscape after cell division, as exemplified by changes in histone modifications of the EpCAM promoter, a target of PRC2 and LSD1/Co-REST/HDAC1 complexes. Notably, liver tumors from X/c-myc bitransgenic mice exhibited downregulation of SUZ12 and ZNF198 along with elevated expression of Plk1, HOTAIR, and EpCAM. Clinically, similar effects were documented in a set of HBV-related liver tumors consistent with the likelihood that downregulation of SUZ12 and ZNF198 leads to epigenetic reprogramming of infected hepatocytes. Because both Plk1 and HOTAIR are elevated in many human cancers, we propose that their combined effects are involved in epigenetic reprogramming associated broadly with oncogenic transformation. Cancer Res; 75(11); 2363–74. ©2015 AACR.
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subset of SUZ12 prc2 target genes is activated during hepatitis b virus replication and liver carcinogenesis associated with hbv x protein
Hepatology, 2012Co-Authors: Leo Studach, Stephan Menne, Stefano Cairo, Marie Annick Buendia, Ronald L Hullinger, Lydie Lefrancois, Philippe Merle, Ourania M AndrisaniAbstract:Chronic hepatitis B virus (HBV) infection is a major risk factor for developing liver cancer, and the HBV X protein (pX) has been implicated as a cofactor in hepatocyte transformation. We have shown that HBV replication as well as in vitro transformation by pX are associated with induction of the mitotic polo-like kinase 1 (Plk1) and down-regulation of the chromatin remodeling components SUZ12 and Znf198. Herein, we demonstrate the same inverse relationship between Plk1 and SUZ12/Znf198 in liver tumors from X/c-myc bitransgenic mice and woodchuck hepatitis virus (WHV)-infected woodchucks. Employing these animal models and the HBV replicating HepAD38 cells we examined the effect of SUZ12/Znf198 down-regulation on gene expression. Genes analyzed include hepatic cancer stem cell markers BAMBI, DKK1,2, DLK1, EpCAM, MYC, and proliferation genes CCNA1, CCND2, IGFII, MCM4-6, PLK1, RPA2, and TYMS. SUZ12 occupancy at the promoters of BAMBI, CCND2, DKK2, DLK1, EpCAM, and IGFII was demonstrated by chromatin immunoprecipitation in untransformed hepatocytes, but was markedly reduced in pX-transformed and SUZ12 knockdown cells. Accordingly, we refer to these genes as “SUZ12 repressed” genes in untransformed hepatocytes. The SUZ12 repressed genes and proliferation genes were induced in HBV-replicating HepAD38 cells and, interestingly, they exhibited distinct expression profiles during hepatocellular carcinoma (HCC) progression in X/c-myc bitransgenics. Specifically, CCND2, EpCAM, and IGFII expression was elevated at the proliferative and preneoplastic stages in X/c-myc bitransgenic livers, whereas BAMBI and PLK1 were overexpressed in hepatic tumors from X/c-myc bitransgenics and WHV-infected woodchucks. Importantly, most of these genes were selectively up-regulated in HBV-induced HCCs. Conclusion: The distinct expression profile of the identified SUZ12 repressed genes in combination with the proliferation genes hold promise as biomarkers for progression of chronic HBV infection to HCC. (HEPATOLOGY 2012)
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proteins znf198 and SUZ12 are down regulated in hepatitis b virus hbv x protein mediated hepatocyte transformation and in hbv replication
Hepatology, 2011Co-Authors: Wenhorng Wang, Leo Studach, Ourania M AndrisaniAbstract:Chronic hepatitis B virus (HBV) infection is a major etiologic factor in hepatocellular carcinoma (HCC) pathogenesis, involving effects of chronic liver inflammation and of the weakly oncogenic HBV X protein (pX). pX-mediated hepatocyte transformation requires Polo-like kinase1 (Plk1) activity, but the mechanism is not fully understood. We identified by a genome-wide short hairpin RNA (shRNA) library screen the genes zinc finger, MYM-type 2 (ZNF198) and suppressor of zeste 12 homolog (Drosophila) (SUZ12) whose protein depletion rescues pX-expressing cells from DNA damage-induced apoptosis. ZNF198 and SUZ12 are components of chromatin remodeling complexes and associate with promyelocytic leukemia (PML) nuclear bodies. Knockdown of ZNF198 and SUZ12 by small interfering RNA (siRNA) reduced p53 stability and DNA repair, rescued pX-expressing hepatocytes from DNA damage-induced apoptosis, and increased pX-induced polyploidy and oncogenic transformation, suggesting ZNF198 and SUZ12 have a role in pX-mediated transformation. Interestingly, during pX-mediated transformation the protein but not messenger RNA (mRNA) levels of ZNF198 and SUZ12 progressively decreased, whereas Plk1 levels increased. Inhibition of Plk1 activity restored protein levels of ZNF198 and SUZ12. In addition, transfected Polo-box-domain (PBD) of Plk1 coimmunoprecipitated with ZNF198 and SUZ12, suggesting that these proteins are Plk1 substrates. Elevated Plk1 and reduced protein levels of ZNF198 and SUZ12 were also observed in human liver cancer cell lines derived from HBV-related tumors and in the presence of HBV replication. Importantly, knockdown by siRNA of ZNF198 and SUZ12 enhanced HBV replication. Conclusion: Reduced protein levels of ZNF198 and SUZ12 and elevated Plk1 occur during pX-mediated hepatocyte transformation in human liver cancer cell lines, as well as during HBV replication, underscoring the significance of these genes both in HBV-mediated HCC pathogenesis and HBV replication. We propose Plk1 activity down-regulates ZNF198 and SUZ12, thereby enhancing both HBV replication and pX-mediated oncogenic transformation. (HEPATOLOGY 2011)
Kristian Helin - One of the best experts on this subject based on the ideXlab platform.
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prc2 loss amplifies ras driven transcription and confers sensitivity to brd4 based therapies
Nature, 2014Co-Authors: Armelle Luscan, Kristian Helin, Thomas De Raedt, Eline Beert, Eric Pasmant, Hilde Brems, Nicolas Ortonne, Jason L HornickAbstract:SUZ12, a component of the PRC2 complex, can also function as a tumour suppressor in certain tumours of the nervous system and melanomas. The PRC2 complex, which regulates gene expression through chromatin modification, has been shown to play a pro-tumorigenic role in many tumours. Karen Cichowski and colleagues now show that SUZ12, a component of PRC2, can also function as a tumour suppressor in certain tumours of the nervous system and melanomas. Through deregulation of chromatin and thereby gene expression, SUZ12 loss cooperates with the loss of NF1, another tumour suppressor frequently lost in these tumours types. At the same time, SUZ12 loss renders tumours sensitive to drugs that target bromodomain proteins, which are currently being explored for a number of cancer types. This work reveals an unexpected connection between PRC2 and several components of the Ras pathway, as well as providing possible targets for epigenetic-based therapies. The polycomb repressive complex 2 (PRC2) exerts oncogenic effects in many tumour types1. However, loss-of-function mutations in PRC2 components occur in a subset of haematopoietic malignancies, suggesting that this complex plays a dichotomous and poorly understood role in cancer2,3. Here we provide genomic, cellular, and mouse modelling data demonstrating that the polycomb group gene SUZ12 functions as tumour suppressor in PNS tumours, high-grade gliomas and melanomas by cooperating with mutations in NF1. NF1 encodes a Ras GTPase-activating protein (RasGAP) and its loss drives cancer by activating Ras4. We show that SUZ12 loss potentiates the effects of NF1 mutations by amplifying Ras-driven transcription through effects on chromatin. Importantly, however, SUZ12 inactivation also triggers an epigenetic switch that sensitizes these cancers to bromodomain inhibitors. Collectively, these studies not only reveal an unexpected connection between the PRC2 complex, NF1 and Ras, but also identify a promising epigenetic-based therapeutic strategy that may be exploited for a variety of cancers.
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middle down hybrid chromatography tandem mass spectrometry workflow for characterization of combinatorial post translational modifications in histones
Proteomics, 2014Co-Authors: Simone Sidoli, Kristian Helin, Veit Schwammle, Chrystian Ruminowicz, Thomas Aarup Hansen, Ole Norregaard JensenAbstract:We present an integrated middle-down proteomics platform for sensitive mapping and quantification of coexisting PTMs in large polypeptides (5-7 kDa). We combined an RP trap column with subsequent weak cation exchange-hydrophilic interaction LC interfaced directly to high mass accuracy ESI MS/MS using electron transfer dissociation. This enabled automated and efficient separation and sequencing of hypermodified histone N-terminal tails for unambiguous localization of combinatorial PTMs. We present Histone Coder and IsoScale software to extract, filter, and analyze MS/MS data, including quantification of cofragmenting isobaric polypeptide species. We characterized histone tails derived from murine embryonic stem cells knockout in suppressor of zeste12 (SUZ12(-/-) ) and quantified 256 combinatorial histone marks in histones H3, H4, and H2A. Furthermore, a total of 713 different combinatorial histone marks were identified in purified histone H3. We measured a seven-fold reduction of H3K27me2/me3 (where me2 and me3 are dimethylation and trimethylation, respectively) in SUZ12(-) (/) (-) cells and detected significant changes of the relative abundance of 16 other single PTMs of histone H3 and other combinatorial marks. We conclude that the inactivation of SUZ12 is associated with changes in the abundance of not only H3K27 methylation but also multiple other PTMs in histone H3 tails.
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quantitative mass spectrometry of histones h3 2 and h3 3 in SUZ12 deficient mouse embryonic stem cells reveals distinct dynamic post translational modifications at lys 27 and lys 36
Molecular & Cellular Proteomics, 2010Co-Authors: Hye Ryung Jung, Diego Pasini, Kristian Helin, Ole Norregaard JensenAbstract:SUZ12 is a core component of the polycomb repressive complex 2 (PRC2) and is required for the differentiation of mouse embryonic stem cells (ESCs). PRC2 is associated with transcriptional repression via methylation of H3 Lys-27. We applied quantitative mass spectrometry to investigate the effects of SUZ12 deficiency on H3.2 and H3.3 from mouse ESCs. Using high mass accuracy MS combined with CID or electron transfer dissociation (ETD) tandem mass spectrometry, we identified a total of 81 unique modified peptides from H3.2 and H3.3 and assigned 46 modifications at 22 different positions, including distinct coexisting modifications. In certain cases, high mass accuracy LTQ-Orbitrap MS/MS allowed precise localization of near isobaric coexisting PTMs such as trimethylation and acetylation within individual peptides. ETD MS/MS facilitated sequencing and annotation of phosphorylated histone peptides. The combined use of ETD and CID MS/MS increased the total number of identified modified peptides. Comparative quantitative analysis of histones from wild type and SUZ12-deficient ESCs using stable isotope labeling with amino acids in cell culture and LC-MS/MS revealed a dramatic reduction of H3K27me2 and H3K27me3 and an increase of H3K27ac, thereby uncovering an antagonistic methyl/acetyl switch at H3K27. The reduction in H3K27 methylation and increase in H3K27 acetylation was accompanied by H3K36 acetylation and methylation. Estimation of the global isoform percentage of unmodified and modified histone peptides (amino acids 27–40) showed the relative distribution of distinct coexisting histone marks. Our study revealed limitations of antibody-based Western blotting methods for detection of coexisting protein modifications and demonstrated the utility of quantitative tandem mass spectrometry for detailed analysis of the dynamics of coexisting post-translational modifications in proteins.
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the polycomb group protein SUZ12 is required for embryonic stem cell differentiation
Molecular and Cellular Biology, 2007Co-Authors: Diego Pasini, Adrian P Bracken, Jacob B Hansen, Manuela Capillo, Kristian HelinAbstract:Polycomb group (PcG) proteins form multiprotein complexes, called Polycomb repressive complexes (PRCs). PRC2 contains the PcG proteins EZH2, SUZ12, and EED and represses transcription through methylation of lysine (K) 27 of histone H3 (H3). SUZ12 is essential for PRC2 activity and its inactivation results in early lethality of mouse embryos. Here, we demonstrate that SUZ12(-/-) mouse embryonic stem (ES) cells can be established and expanded in tissue culture. The SUZ12(-/-) ES cells are characterized by global loss of H3K27 trimethylation (H3K27me3) and higher expression levels of differentiation-specific genes. Moreover, SUZ12(-/-) ES cells are impaired in proper differentiation, resulting in a lack of repression of ES cell markers as well as activation of differentiation-specific genes. Finally, we demonstrate that the PcGs are actively recruited to several genes during ES cell differentiation, which despite an increase in H3K27me3 levels is not always sufficient to prevent transcriptional activation. In summary, we demonstrate that SUZ12 is required for the establishment of specific expression programs required for ES cell differentiation. Furthermore, we provide evidence that PcGs have different mechanisms to regulate transcription during cellular differentiation.
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SUZ12 is essential for mouse development and for ezh2 histone methyltransferase activity
The EMBO Journal, 2004Co-Authors: Diego Pasini, Adrian P Bracken, Michael Rugaard Jensen, Eros Lazzerini Denchi, Kristian HelinAbstract:SUZ12 is a recently identified Polycomb group (PcG) protein, which together with EZH2 and EED forms different Polycomb repressive complexes (PRC2/3). These complexes contain histone H3 lysine (K) 27/9 and histone H1 K26 methyltransferase activity specified by the EZH2 SET domain. Here we show that mice lacking SUZ12 , like Ezh2 and Eed mutant mice, are not viable and die during early postimplantation stages displaying severe developmental and proliferative defects. Consistent with this, we demonstrate that SUZ12 is required for proliferation of cells in tissue culture. Furthermore, we demonstrate that SUZ12 is essential for the activity and stability of the PRC2/3 complexes in mouse embryos, in tissue culture cells and in vitro . Strikingly, SUZ12‐deficient embryos show a specific loss of di‐ and trimethylated H3K27, demonstrating that SUZ12 is indeed essential for EZH2 activity in vivo . In conclusion, our data demonstrate an essential role of SUZ12 in regulating the activity of the PRC2/3 complexes, which are required for regulating proliferation and embryogenesis.
Margarita Sanchezbeato - One of the best experts on this subject based on the ideXlab platform.
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SUZ12 promotes human epithelial ovarian cancer by suppressing apoptosis via silencing hrk
Molecular Cancer Research, 2012Co-Authors: Qi Cai, Vinod Vathipadiekal, Zachary C Dobbin, Xiang Hua, Charles N Landen, Michael J Birrer, Margarita Sanchezbeato, Rugang ZhangAbstract:Epithelial ovarian cancer (EOC) ranks first as the cause of death for gynecological cancers in the United States. SUZ12 is a component of the polycomb repressive complex 2 (PRC2) and is essential for PRC2-mediated gene silencing by generating trimethylation on lysine 27 residue of histone H3 (H3K27Me3). The role of SUZ12 in EOC has never been investigated. Here, we show that SUZ12 is expressed at significantly higher levels in human EOC (n = 117) compared with either normal human ovarian surface epithelium (n = 35, P < 0.001) or fallopian tube epithelium (n = 15, P < 0.001). There is a positive correlation between expression of SUZ12 and EZH2 in human EOC (P < 0.001). In addition, expression of SUZ12 positively correlates with Ki67, a marker of cell proliferation (P < 0.001), and predicts shorter overall survival (P = 0.0078). Notably, knockdown of SUZ12 suppresses the growth of human EOC cells in vitro and in vivo in both orthotopic and subcutaneous xenograft EOC models. In addition, SUZ12 knockdown decreases the levels of H3K27Me3 and triggers apoptosis of human EOC cells. Mechanistically, we identified Harakiri (HRK), a proapoptotic gene, as a novel SUZ12 target gene, and showed that HRK upregulation mediates apoptosis induced by SUZ12 knockdown in human EOC cells. In summary, we show that SUZ12 promotes the proliferation of human EOC cells by inhibiting apoptosis and HRK is a novel SUZ12 target gene whose upregulation contributes to apoptosis induced by SUZ12 knockdown.
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deregulated expression of the polycomb group protein SUZ12 target genes characterizes mantle cell lymphoma
American Journal of Pathology, 2010Co-Authors: Daniel Martinperez, Esther Maria Sanchez Sanchez, Lorena Maestre, Javier Suela, Pierfrancesco Vargiu, Lorena Di Lisio, Nerea Martinez, Javier Alves, Miguel A Piris, Margarita SanchezbeatoAbstract:Polycomb proteins are known to be of great importance in human cancer pathogenesis. SUZ12 is a component of the Polycomb PRC2 complex that, along with EZH2, is involved in embryonic stem cell differentiation. EZH2 plays an essential role in many cancer types, but an equivalent involvement of SUZ12 has not been as thoroughly demonstrated. Here we show that SUZ12 is anomalously expressed in human primary tumors, especially in mantle cell lymphoma (MCL), pulmonary carcinomas and melanoma, and is associated with gene locus amplification in some cases. Using MCL as a model, functional and genomic studies demonstrate that SUZ12 loss compromises cell viability, increases apoptosis, and targets genes involved in central oncogenic pathways associated with MCL pathogenesis. Our results support the hypothesis that the abnormal expression of SUZ12 accounts for some of the unexplained features of MCL, such as abnormal DNA repair and increased resistance to apoptosis.
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SUZ12 overexpression in human tumors is associated with tumoral transformation and its depletion affects mantle cell lymphoma cell lines viability
Cancer Research, 2007Co-Authors: Daniel Martinperez, Esther Maria Sanchez Sanchez, Lorena Maestre, Miguel Angel Piris, Margarita SanchezbeatoAbstract:375 Polycomb Group (PcG) members are known transcriptional repressors with an important function in development by means of the control of HOX genes expression. PcG proteins exert its function by forming DNA-binding repressive complexes that are able to change chromatin structure through epigenetic mechanisms. Many studies suggest a role for PcG members in stem cell self-renewal and cell fate decisions. Recent studies have demonstrated the importance of certain PcG proteins in several types of human tumour. For instance BMI1 is involved in lymphomagenesis and other tumours; EZH2 has a role in prostate cancer progression and in neoplastic transformation of breast epithelial cells and SUZ12 mRNA has been found to be up-regulated in a number of different human tumours, including tumours of the colon and breast. We have studied the expression of EZH2 and SUZ12 in non-tumoral (154 samples) and tumoral (550 samples) human tumours by using tissue microarrays. Although these two proteins form part of the same complex, EZH2 was ubiquitously expressed in every normal and tumoral tissue while SUZ12 was selectively expressed in germ cells, proliferating cells (germinal centre cells) in lymph nodes and in epithelial cells of different tissues. SUZ12 protein is also over represented in some tumours in contrast with the normal counterpart. Among these tumours we have found colonic adenomas, lung neuroendocrine small-cell carcinoma, melanoma and mantle cell lymphoma (MCL). MCL patients that overexpress SUZ12 show a shorter survival than patients that do not overexpress this protein. To address the function of SUZ12 in MCL we have performed functional RNAi-based assays against this gene. We have infected Jeko1 and Z138 MCL cell lines with lentivirus carrying either two different shRNAs against SUZ12 or a scramble oligo using GFP as a marker. After successful knock-down, GFP positive cells showed a competitive disadvantage when infected with the SUZ12 silencing oligos compared with GFP negative cells while GFP positive cells in the scramble control had the same behaviour as non-infected cells. After 8 passages the percentage of GFP positive cells was reduced around 50% in the silenced cells and the remaining GFP positive cells did not show repression of SUZ12, suggesting that the effect of the depletion of SUZ12 is stronger than the effect measured by the competition assay. Results of Gene Expression Profile comparing control cells versus SUZ12 deficient cells will be discussed in the poster.
Jeffrey Sklar - One of the best experts on this subject based on the ideXlab platform.
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the jazf1 SUZ12 fusion protein disrupts prc2 complexes and impairs chromatin repression during human endometrial stromal tumorogenesis
Oncotarget, 2017Co-Authors: Jinglan Wang, Jianhui Wang, Charles X, Xiaobin Gao, Vytas Patriub, Jeffrey SklarAbstract:// Xianyong Ma 1 , Jinglan Wang 1 , Jianhui Wang 1 , Charles X. Ma 2 , Xiaobin Gao 1 , Vytas Patriub 1 , Jeffrey L. Sklar 1 1 Department of Pathology, Yale University School of Medicine, New Haven, CT, USA 2 University of Connecticut School of Medicine, Farmington, CT, USA Correspondence to: Xianyong Ma, email: xian-yong.ma@yale.edu Keywords: SUZ12 and PRC2 complex, endometrial stromal Sarcoma (ESS), t(7,17) translocation, histone methyl transferase (HMT), H3K27Me3 Received: September 17, 2015 Accepted: October 29, 2016 Published: November 10, 2016 ABSTRACT The Polycomb repressive complex 2 (PRC2), which contains three core proteins EZH2, EED and SUZ12, controls chromatin compaction and transcription repression through trimethylation of lysine 27 on histone 3. The (7;17)(p15;q21) chromosomal translocation present in most cases of endometrial stromal sarcomas (ESSs) results in the in-frame fusion of the JAZF1 and SUZ12 genes. We have investigated whether and how the fusion protein JAZF1-SUZ12 functionally alters PRC2. We found that the fusion protein exists at high levels in ESS containing the t(7;17). Co-transient transfection assay indicated JAZF1-SUZ12 destabilized PRC2 components EZH2 and EED, resulting in decreased histone methyl transferase (HMT) activity, which was confirmed by in vitro studies using reconstituted PRC2 and nucleosome array substrates. We also demonstrated the PRC2 containing the fusion protein decreased the binding affinity to target chromatin loci. In addition, we found that trimethylation of H3K27 was decreased in ESS samples with the t(7;17), but there was no detectable change in H3K9 in these tissues. Moreover, re-expression of SUZ12 in SUZ12 (−/−) ES cells rescued the neuronal differentiation while the fusion protein failed to restore this function and enhanced cell proliferation. In summary, our studies reveal that JAZF1-SUZ12 fusion protein disrupts the PRC2 complex, abolishes HMT activity and subsequently activates chromatin/genes normally repressed by PRC2. Such dyesfunction of PRC2 inhibits normal neural differentiation of ES cell and increases cell proliferation. Related changes induced by the JAZF-SUZ12 protein in endometrial stromal cells may explain the oncogenic effect of the t(7;17) in ESS.
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effects of rearrangement and allelic exclusion of jjaz1 SUZ12 on cell proliferation and survival
Proceedings of the National Academy of Sciences of the United States of America, 2007Co-Authors: Jinglan Wang, Jason I. Koontz, Marisa R. Nucci, Jeffrey SklarAbstract:Polycomb group genes (PcGs) have been implicated in cancer based on altered levels of expression observed in certain tumors and the behavior of cultured cells containing inserted PcG transgenes. Endometrial stromal tumors provide evidence for a direct causal relationship because they contain several chromosomal translocations and resultant gene fusions involving PcGs, the most common of which joins portions of theJAZF1 gene to the PcGJJAZ1/SUZ12. We show here that both benign and malignant forms of this tumor have theJAZF1–JJAZ1 fusion but only the malignant form also exhibits exclusion of the unrearrangedJJAZ1 allele. To evaluate the effects of both theJJAZ1/SUZ12 fusion and allelic exclusion on functions related to cell growth, we studied HEK293 cells that were modified with respect toJJAZ1 expression. We found that theJAZF1–JJAZ1 fusion restored levels of the polycomb protein EZH2 and histone 3 lysine 27 trimethylation, which were reduced by knockdown of endogenous JJAZ1. At the same time, the presence ofJAZF1–JJAZ1 markedly inhibited apoptosis and induced above normal proliferation rates, although the latter effect occurred only when normalJJAZ1 was suppressed. Our findings suggest a genetic pathway for progression of a benign precursor to a sarcoma involving increased cell survival associated with acquisition of a PcG rearrangement, followed by accelerated cellular proliferation upon allelic exclusion of the unrearranged copy of that gene. Furthermore, these results indicate the likely functional importance of allelic exclusion of genes disrupted by chromosomal translocations, as seen in a variety of other cancers.
