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1.
Anticancer Res ; 39(8): 4179-4184, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31366503

RESUMO

BACKGROUND/AIM: Enhancer of zeste homolog 2 (EZH2), the catalytic subunit of polycomb repressive complex 2 (PRC2), possesses histone N-methyltransferase (HMT) activity and plays an essential role in cancer initiation and development. The aim of the present study was to investigate the potential of Wedelolactone (WL) to inhibit the methylation activity of EZH2. MATERIALS AND METHODS: The mantle cell lymphoma (MCL) cell line, Mino, was treated with WL, while untreated cells were used as control. HMT activity and EZH2 amount were measured in nuclear extracts from WL-treated and control Mino cells. RESULTS: WL was found to target EZH2-mediated histone H3K27 methylation. Along with the inhibition of H3K27 methylation in vitro (IC50=0.3 µM), WL suppressed HMT activity in Mino cells with an IC50 value of 3.2 µM. We detected a reduced amount of EZH2 in Mino cells treated with WL, compared to untreated control cells. CONCLUSION: This is the first study to show that WL induces inhibition of H3K27 methylation via EZH2 modulation and decreases cell proliferation in MCL, in vitro. WL is proposed as a promising agent and a novel epigenetic approach in MCL investigation and treatment.


Assuntos
Cumarínicos/farmacologia , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Código das Histonas/genética , Linfoma de Célula do Manto/tratamento farmacológico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Código das Histonas/efeitos dos fármacos , Histona Metiltransferases/genética , Histona Metiltransferases/metabolismo , Histonas/genética , Histonas/metabolismo , Humanos , Linfoma de Célula do Manto/genética , Linfoma de Célula do Manto/patologia , Metilação/efeitos dos fármacos , Complexo Repressor Polycomb 2/genética
2.
Nat Commun ; 10(1): 2901, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31263101

RESUMO

Dysregulation of histone modifications promotes carcinogenesis by altering transcription. Breast cancers frequently overexpress the histone methyltransferase EZH2, the catalytic subunit of Polycomb Repressor Complex 2 (PRC2). However, the role of EZH2 in this setting is unclear due to the context-dependent functions of PRC2 and the heterogeneity of breast cancer. Moreover, the mechanisms underlying PRC2 overexpression in cancer are obscure. Here, using multiple models of breast cancer driven by the oncogene ErbB2, we show that the tyrosine kinase c-Src links energy sufficiency with PRC2 overexpression via control of mRNA translation. By stimulating mitochondrial ATP production, c-Src suppresses energy stress, permitting sustained activation of the mammalian/mechanistic target of rapamycin complex 1 (mTORC1), which increases the translation of mRNAs encoding the PRC2 subunits Ezh2 and Suz12. We show that Ezh2 overexpression and activity are pivotal in ErbB2-mediated mammary tumourigenesis. These results reveal the hitherto unknown c-Src/mTORC1/PRC2 axis, which is essential for ErbB2-driven carcinogenesis.


Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Epigênese Genética , Complexo Repressor Polycomb 2/genética , Receptor ErbB-2/metabolismo , Quinases da Família src/metabolismo , Trifosfato de Adenosina/metabolismo , Adulto , Animais , Neoplasias da Mama/patologia , Carcinogênese , Linhagem Celular Tumoral , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Feminino , Humanos , Glândulas Mamárias Humanas/metabolismo , Glândulas Mamárias Humanas/patologia , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Camundongos Endogâmicos NOD , Camundongos Transgênicos , Pessoa de Meia-Idade , Mitocôndrias/genética , Mitocôndrias/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Biossíntese de Proteínas , Receptor ErbB-2/genética , Quinases da Família src/genética
3.
Genes Dev ; 33(15-16): 903-935, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31123062

RESUMO

As the process that silences gene expression ensues during development, the stage is set for the activity of Polycomb-repressive complex 2 (PRC2) to maintain these repressed gene profiles. PRC2 catalyzes a specific histone posttranslational modification (hPTM) that fosters chromatin compaction. PRC2 also facilitates the inheritance of this hPTM through its self-contained "write and read" activities, key to preserving cellular identity during cell division. As these changes in gene expression occur without changes in DNA sequence and are inherited, the process is epigenetic in scope. Mutants of mammalian PRC2 or of its histone substrate contribute to the cancer process and other diseases, and research into these aberrant pathways is yielding viable candidates for therapeutic targeting. The effectiveness of PRC2 hinges on its being recruited to the proper chromatin sites; however, resolving the determinants to this process in the mammalian case was not straightforward and thus piqued the interest of many in the field. Here, we chronicle the latest advances toward exposing mammalian PRC2 and its high maintenance.


Assuntos
Epigênese Genética , Regulação da Expressão Gênica , Complexo Repressor Polycomb 2/genética , Complexo Repressor Polycomb 2/metabolismo , Animais , Cromatina/metabolismo , Humanos , Mutação , Neoplasias/genética , Neoplasias/fisiopatologia , Transporte Proteico , Pesquisa/tendências
4.
Planta ; 250(2): 573-588, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31127375

RESUMO

MAIN CONCLUSION: The information on core components in maize polycomb repressive complex 2 (PRC2) are updated at a genome-wide scale, and the protein-protein interaction networks of PRC2 components are further provided in maize. The evolutionarily conserved polycomb group (PcG) proteins form multi-subunits polycomb repressive complexes (PRCs) that repress gene expression via chromatin condensation. In Arabidopsis, three distinct PRC2s have been identified, each determining a specific developmental program with partly functional redundancy. However, the core components and biological functions of PRC2 in cereals remain obscure. Here, we updated the information on maize PRC2 components at a genome-wide scale. Maize PRC2 subunits are highly duplicated, with five MSI1, three E(z), two ESC and two Su(z)12 homologs. ZmFIE1 is preferentially expressed in the endosperm, whereas the remaining are broadly expressed in many tissues. ZmCLF/MEZ1 and ZmFIE1 are maternally expressed imprinted genes, in contrast to the paternal-dominantly expression of ZmFIE2 in the endosperm. In maize, E(z) members likely provide a scaffold for assembling PRC2 complexes, whereas Su(z)12 and p55/MSI1-like proteins together reinforce the complex; ESC members probably determine its specificity: FIE1-PRC2 regulates endosperm cell development, whereas FIE2-PRC2 controls other cell types. The duplicated Brassicaceae-specific MEA and FIS2 also directly interact with maize PRC2 members. Together, this study establishes a roadmap for protein-protein interactions of maize PRC2 components, providing new insights into their functions in the growth and development of cereals.


Assuntos
Complexo Repressor Polycomb 2/metabolismo , Zea mays/enzimologia , Alelos , Arabidopsis/enzimologia , Arabidopsis/genética , Endosperma/enzimologia , Endosperma/genética , Endosperma/ultraestrutura , Epigenômica , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Complexo Repressor Polycomb 2/genética , Domínios Proteicos , Técnicas do Sistema de Duplo-Híbrido , Zea mays/genética , Zea mays/ultraestrutura
5.
Pathobiology ; 86(2-3): 152-161, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31096221

RESUMO

INTRODUCTION: The interaction of K27M mutation in histone H3 (H3K27M mutation) with polycomb repressive complex 2 (PRC2) is facilitated by the enhancer of zeste homolog 2 (EZH2). Subsequently, this interaction leads to the global reduction level of H3K27me3. We analyzed the EZH2 expression level in H3K27M mutation-positive tumors and revealed the association of high EZH2 expression with poor survival. METHODS: Our study included 12 patients, with an age range of 6-56 years and treated between 2007 and 2016. All patients underwent MRI study for nonenhanced T1, T2, diffusion, gadolinium-enhanced T1-weighted imaging, and fluid-attenuated inversion recovery (FLAIR). Immunohistochemical staining was performed against H3K27M, H3K27me3, EZH2, EED, mutant isocitrate dehydrogenase 1 (IDH1), α-thalassemia X-linked intellectual disability (ATRX), p53, O6-methylguanine-DNA methyltransferase (MGMT), and Ki-67 antibodies. RESULTS: All patients were negative for IDH1R132H and H3K27me3, but H3K27M-positive. Staining against EZH2 was negative in all histological features of grade II cases (3/12) and positive in grade III and IV cases; EZH2 positivity is associated with poor prognosis (p = 0.0082). EZH2 positivity was not associated with EED positivity. Retained ATRX staining was found mostly in grade III and IV cases (6/12). P53 was predominantly positive in cases of astrocytoma and glioblastoma (8/12). The labeling index of Ki-67 was 1.2-31.4% for grade II and III histological features and 11.2-24.8% for grade IV. CONCLUSION: We suggest that the expression of EZH2 is not associated with the PRC2 pathway and increases in patients with H3K27M-mutant diffuse midline glioma and a poor prognosis. Further studies are necessary to understand the mechanism involved.


Assuntos
Neoplasias Encefálicas/genética , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Glioma/genética , Mutação , Adolescente , Adulto , Neoplasias Encefálicas/diagnóstico , Criança , Feminino , Glioma/diagnóstico , Histonas/genética , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Complexo Repressor Polycomb 2/genética , Prognóstico , Coloração e Rotulagem , Análise de Sobrevida , Adulto Jovem
6.
Nat Commun ; 10(1): 1931, 2019 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-31036804

RESUMO

Polycomb group (PcG) proteins play critical roles in the epigenetic inheritance of cell fate. The Polycomb Repressive Complexes PRC1 and PRC2 catalyse distinct chromatin modifications to enforce gene silencing, but how transcriptional repression is propagated through mitotic cell divisions remains a key unresolved question. Using reversible tethering of PcG proteins to ectopic sites in mouse embryonic stem cells, here we show that PRC1 can trigger transcriptional repression and Polycomb-dependent chromatin modifications. We find that canonical PRC1 (cPRC1), but not variant PRC1, maintains gene silencing through cell division upon reversal of tethering. Propagation of gene repression is sustained by cis-acting histone modifications, PRC2-mediated H3K27me3 and cPRC1-mediated H2AK119ub1, promoting a sequence-independent feedback mechanism for PcG protein recruitment. Thus, the distinct PRC1 complexes present in vertebrates can differentially regulate epigenetic maintenance of gene silencing, potentially enabling dynamic heritable responses to complex stimuli. Our findings reveal how PcG repression is potentially inherited in vertebrates.


Assuntos
Cromatina/metabolismo , Epigênese Genética , Inativação Gênica , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 2/genética , Processamento de Proteína Pós-Traducional , Animais , Linhagem Celular , Cromatina/química , Retroalimentação Fisiológica , Histonas/genética , Histonas/metabolismo , Padrões de Herança , Camundongos , Mitose , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/metabolismo , Complexo Repressor Polycomb 1/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Transcrição Genética
7.
Mol Cell ; 74(1): 8-18, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30951652

RESUMO

The polycomb repressive complex 2 (PRC2) is a chromatin-associated methyltransferase catalyzing mono-, di-, and trimethylation of lysine 27 on histone H3 (H3K27). This activity is required for normal organismal development and maintenance of gene expression patterns to uphold cell identity. PRC2 function is often deregulated in disease and is a promising candidate for therapeutic targeting in cancer. In this review, we discuss the molecular mechanisms proposed to take part in modulating PRC2 recruitment and shaping H3K27 methylation patterns across the genome. This includes consideration of factors influencing PRC2 residence time on chromatin and PRC2 catalytic activity with a focus on the mechanisms giving rise to regional preferences and differential deposition of H3K27 methylation. We further discuss existing evidence for functional diversity between distinct subsets of PRC2 complexes with the aim of extracting key concepts and highlighting major open questions toward a more complete understanding of PRC2 function.


Assuntos
Metilação de DNA , Histonas/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Animais , Montagem e Desmontagem da Cromatina , Humanos , Lisina , Metilação , Complexo Repressor Polycomb 2/genética , Ligação Proteica
8.
Nat Commun ; 10(1): 1679, 2019 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-30976011

RESUMO

The Polycomb repressive complexes PRC1 and PRC2 act non-redundantly at target genes to maintain transcriptional programs and ensure cellular identity. PRC2 methylates lysine 27 on histone H3 (H3K27me), while PRC1 mono-ubiquitinates histone H2A at lysine 119 (H2Aub1). Here we present engineered mouse embryonic stem cells (ESCs) targeting the PRC2 subunits EZH1 and EZH2 to discriminate between contributions of distinct H3K27 methylation states and the presence of PRC2/1 at chromatin. We generate catalytically inactive EZH2 mutant ESCs, demonstrating that H3K27 methylation, but not recruitment to the chromatin, is essential for proper ESC differentiation. We further show that EZH1 activity is sufficient to maintain repression of Polycomb targets by depositing H3K27me2/3 and preserving PRC1 recruitment. This occurs in the presence of altered H3K27me1 deposition at actively transcribed genes and by a diffused hyperacetylation of chromatin that compromises ESC developmental potential. Overall, this work provides insights for the contribution of diffuse chromatin invasion by acetyltransferases in PRC2-dependent loss of developmental control.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Histonas/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Processamento de Proteína Pós-Traducional/fisiologia , Acetilação , Animais , Diferenciação Celular/fisiologia , Cromatina/metabolismo , Metilação de DNA/fisiologia , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Técnicas de Inativação de Genes , Camundongos , Células-Tronco Embrionárias Murinas , Complexo Repressor Polycomb 1/metabolismo , Complexo Repressor Polycomb 2/genética
9.
Proc Natl Acad Sci U S A ; 116(13): 6075-6080, 2019 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-30867289

RESUMO

Genetic mutations affecting chromatin modifiers are widespread in cancers. In malignant peripheral nerve sheath tumors (MPNSTs), Polycomb repressive complex 2 (PRC2), which plays a crucial role in gene silencing, is inactivated through recurrent mutations in core subunits embryonic ectoderm development (EED) and suppressor of zeste 12 homolog (SUZ12), but mutations in PRC2's main catalytic subunit enhancer of zeste homolog 2 (EZH2) have never been found. This is in contrast to myeloid and lymphoid malignancies, which harbor frequent loss-of-function mutations in EZH2. Here, we investigated whether the absence of EZH2 mutations in MPNST is due to a PRC2-independent (i.e., noncanonical) function of the enzyme or to redundancy with EZH1. We show that, in the absence of SUZ12, EZH2 remains bound to EED but loses its interaction with all other core and accessory PRC2 subunits. Through genetic and pharmacological analyses, we unambiguously establish that EZH2 is functionally inert in this context, thereby excluding a PRC2-independent function. Instead, we show that EZH1 and EZH2 are functionally redundant in the slowly proliferating MPNST precursors. We provide evidence that the compensatory function of EZH1 is alleviated upon higher proliferation. This work reveals how context-dependent redundancies can shape tumor-type specific mutation patterns in chromatin regulators.


Assuntos
Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Neoplasias/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Cromatina/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Mutação/genética , Neoplasias/genética , Neurofibroma/genética , Neurofibroma/metabolismo , Complexo Repressor Polycomb 2/genética
10.
Mol Cell ; 74(1): 101-117.e10, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30827740

RESUMO

During X-inactivation, Xist RNA spreads along an entire chromosome to establish silencing. However, the mechanism and functional RNA elements involved in spreading remain undefined. By performing a comprehensive endogenous Xist deletion screen, we identify Repeat B as crucial for spreading Xist and maintaining Polycomb repressive complexes 1 and 2 (PRC1/PRC2) along the inactive X (Xi). Unexpectedly, spreading of these three factors is inextricably linked. Deleting Repeat B or its direct binding partner, HNRNPK, compromises recruitment of PRC1 and PRC2. In turn, ablating PRC1 or PRC2 impairs Xist spreading. Therefore, Xist and Polycomb complexes require each other to propagate along the Xi, suggesting a positive feedback mechanism between RNA initiator and protein effectors. Perturbing Xist/Polycomb spreading causes failure of de novo Xi silencing, with partial compensatory downregulation of the active X, and also disrupts topological Xi reconfiguration. Thus, Repeat B is a multifunctional element that integrates interdependent Xist/Polycomb spreading, silencing, and changes in chromosome architecture.


Assuntos
Fibroblastos/metabolismo , Deleção de Genes , Inativação Gênica , Células-Tronco Embrionárias Murinas/metabolismo , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 2/genética , RNA Longo não Codificante/genética , Inativação do Cromossomo X , Cromossomo X/genética , Animais , Linhagem Celular Transformada , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Masculino , Camundongos , Motivos de Nucleotídeos , Complexo Repressor Polycomb 1/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Ligação Proteica , RNA Longo não Codificante/metabolismo , Sequências Repetitivas de Ácido Nucleico , Ribonucleoproteínas/genética , Ribonucleoproteínas/metabolismo , Cromossomo X/metabolismo
11.
J Hum Genet ; 64(6): 561-572, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30858506

RESUMO

Variants have been identified in the embryonic ectoderm development (EED) gene in seven patients with syndromic overgrowth similar to that observed in Weaver syndrome. Here, we present three additional patients with missense variants in the EED gene. All the missense variants reported to date (including the three presented here) have localized to one of seven WD40 domains of the EED protein, which are necessary for interaction with enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2). In addition, among the seven patients reported in the literature and the three new patients presented here, all of the reported pathogenic variants except one occurred at one of four amino acid residues in the EED protein. The recurrence of pathogenic variation at these loci suggests that these residues are functionally important (mutation hotspots). In silico modeling and calculations of the free energy changes resulting from these variants suggested that they not only destabilize the EED protein structure but also adversely affect interactions between EED, EZH2, and/or H3K27me3. These cases help demonstrate the mechanism(s) by which apparently deleterious variants in the EED gene might cause overgrowth and lend further support that amino acid residues in the WD40 domain region may be mutation hotspots.


Assuntos
Anormalidades Múltiplas/genética , Hipotireoidismo Congênito/genética , Anormalidades Craniofaciais/genética , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Deformidades Congênitas da Mão/genética , Histona-Lisina N-Metiltransferase/genética , Complexo Repressor Polycomb 2/genética , Anormalidades Múltiplas/etiologia , Anormalidades Múltiplas/fisiopatologia , Adolescente , Criança , Simulação por Computador , Hipotireoidismo Congênito/etiologia , Hipotireoidismo Congênito/fisiopatologia , Anormalidades Craniofaciais/etiologia , Anormalidades Craniofaciais/fisiopatologia , Proteína Potenciadora do Homólogo 2 de Zeste/química , Feminino , Deformidades Congênitas da Mão/etiologia , Deformidades Congênitas da Mão/fisiopatologia , Histona-Lisina N-Metiltransferase/química , Humanos , Masculino , Simulação de Dinâmica Molecular , Taxa de Mutação , Mutação de Sentido Incorreto/genética , Complexo Repressor Polycomb 2/química , Conformação Proteica , Repetições WD40/genética , Sequenciamento Completo do Exoma
12.
Gastroenterology ; 156(6): 1834-1848, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30689973

RESUMO

BACKGROUND & AIMS: Little is known about mechanisms that underlie postnatal hepatocyte maturation and fibrosis at the chromatin level. We investigated the transcription of genes involved in maturation and fibrosis in postnatal hepatocytes of mice, focusing on the chromatin compaction the roles of the Polycomb repressive complex 2 histone methyltransferases EZH1 and EZH2. METHODS: Hepatocytes were isolated from mixed background C57BL/6J-C3H mice, as well as mice with liver-specific disruption of Ezh1 and/or Ezh2, at postnatal day 14 and 2 months after birth. Liver tissues were collected and analyzed by RNA sequencing, H3K27me3 chromatin immunoprecipitation sequencing, and sonication-resistant heterochromatin sequencing (a method to map heterochromatin and euchromatin). Liver damage was characterized by histologic analysis. RESULTS: We found more than 3000 genes differentially expressed in hepatocytes during liver maturation from postnatal day 14 to month 2 after birth. Disruption of Ezh1 and Ezh2 in livers caused perinatal hepatocytes to differentiate prematurely and to express genes at postnatal day 14 that would normally be induced by month 2 and differentiate prematurely. Loss of Ezh1 and Ezh2 also resulted in liver fibrosis. Genes with H3K27me3-postive and H3K4me3-positive euchromatic promoters were prematurely induced in hepatocytes with loss of Ezh1 and Ezh2-these genes included those that regulate hepatocyte maturation, fibrosis, and genes not specifically associated with the liver lineage. CONCLUSIONS: The Polycomb repressive complex 2 proteins EZH1 and EZH2 regulate genes that control hepatocyte maturation and fibrogenesis and genes not specifically associated with the liver lineage by acting at euchromatic promoter regions. EZH1 and EZH2 thereby promote liver homeostasis and prevent liver damage. Strategies to manipulate Polycomb proteins might be used to improve hepatocyte derivation protocols or developed for treatment of patients with liver fibrosis.


Assuntos
Diferenciação Celular/genética , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Repressão Epigenética , Regulação da Expressão Gênica/genética , Cirrose Hepática/genética , Complexo Repressor Polycomb 2/genética , Animais , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Eucromatina , Feminino , Expressão Gênica , Ontologia Genética , Hepatócitos , Histonas/metabolismo , Cirrose Hepática/patologia , Masculino , Metilação , Camundongos , Complexo Repressor Polycomb 2/metabolismo , Regiões Promotoras Genéticas , Fatores de Tempo
13.
Med Sci Monit ; 25: 801-810, 2019 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-30688289

RESUMO

BACKGROUND Acute kidney injury (AKI) involves the renal tubular epithelium. The enhancer of zeste homolog 1 (EZH1) gene has a role in cell development and differentiation. This study aimed to investigate the effect of overexpression of the EZH1 gene on aristolochic acid-induced injury in HK-2 human kidney proximal tubule epithelial cells in vitro. MATERIAL AND METHODS The HK-2 cells were cultured and treated with aristolochic acid and the effects of aristolochic acid-injury were evaluated using a cell counting kit-8 (CCK-8) assay. Overexpression of EZH1 used gene plasmid transfection into HK-2 cells. The cell apoptosis rate and levels of intracellular reactive oxygen species (ROS) were measured using flow cytometry. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were performed to determine the expressions of inflammatory cytokines including interleukin (IL)-1ß, IL-6, tumor necrosis factor-α (TNF-α), apoptosis-related genes, and the downstream target genes of NF-κB signaling pathway, including NFKBIA, CXCL8, and cyclin D1. RESULTS Aristolochic acid inhibited HK-2 cell viability, induced cell apoptosis, increased the levels of ROS and inflammatory cytokines, including IL-1ß, IL-6, TNF-α, and activated the NF-κB pathway. Overexpression the EZH1 gene inhibited HK-2 cell apoptosis, reduced ROS levels, and down-regulated the expressions of IL-1ß, IL-6, TNF-α, Bax and Cyt C mRNA and protein, and increased the expressions of Bcl-2 and NFKBIA, CXCL8 and cyclin D1, indicating that overexpression of EZH1 suppressed NF-κB signaling in aristolochic acid-injured HK-2 cells. CONCLUSIONS Overexpression of EZH1 reduced HK-2 cell injury induced by aristolochic acid in vitro by inhibition of NF-κB signaling.


Assuntos
Lesão Renal Aguda/metabolismo , Túbulos Renais Proximais/efeitos dos fármacos , Complexo Repressor Polycomb 2/metabolismo , Lesão Renal Aguda/induzido quimicamente , Lesão Renal Aguda/patologia , Apoptose/efeitos dos fármacos , Ácidos Aristolóquicos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Citocinas/metabolismo , Células Epiteliais/metabolismo , Humanos , Inflamação/patologia , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Rim/efeitos dos fármacos , Rim/patologia , Túbulos Renais Proximais/patologia , NF-kappa B/metabolismo , Complexo Repressor Polycomb 2/biossíntese , Complexo Repressor Polycomb 2/genética , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo
14.
Genome Res ; 28(8): 1147-1157, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29970451

RESUMO

We provide a comprehensive genomic and epigenomic map of the more than 500,000 endogenous retroviruses (ERVs) and fragments that populate the intergenic regions of the human genome. The repressive epigenetic marks associated with the ERVs, particularly long terminal repeats (LTRs), show a remarkable switch in silencing mechanisms, depending on the evolutionary age of the LTRs. Young LTRs tend to be CpG rich and are mainly suppressed by DNA methylation, whereas intermediate age LTRs are associated predominantly with histone modifications, particularly histone H3 lysine 9 (H3K9) methylation. Young LTRs can be reactivated by treatment with the DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-aza-CdR) alone, but their level of expression is much increased by 5-aza-CdR treatment plus knockdown of one of several H3K9 methyltransferases or of the H3K27 methyltransferase EZH2. The removal of cytosine methylation led to rapid, widespread increases in H3K9me3 in the LTRs. Intermediate age LTRs had lower CpG densities and were not up-regulated by 5-aza-CdR treatment, but they were sensitive to knockdown of H3K9 methyltransferases. Unlike the situation in embryonic stem cells, the polycomb repressive complex (PRC2) has a minor role in LTR suppression by itself and is only a player after removal of cytosine methylation in the analyzed cancer cell line. Up-regulation of LTRs and induction of "viral mimicry" is rapidly becoming of interest for predicting cancer patient response to epigenetic therapies. Understanding the mechanism for LTR suppression is of major importance in order to improve patient treatment strategies.


Assuntos
Ilhas de CpG/genética , Metilação de DNA/genética , Retrovirus Endógenos/genética , Sequências Repetidas Terminais/genética , Células-Tronco Embrionárias/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Inativação Gênica , Histona-Lisina N-Metiltransferase/genética , Histonas/genética , Humanos , Complexo Repressor Polycomb 2/genética , Processamento de Proteína Pós-Traducional
15.
Genes Dev ; 32(11-12): 794-805, 2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29891558

RESUMO

Polycomb-repressive complex 2 (PRC2) is a histone methyltransferase that promotes epigenetic gene silencing, but the dynamics of its interactions with chromatin are largely unknown. Here we quantitatively measured the binding of PRC2 to chromatin in human cancer cells. Genome editing of a HaloTag into the endogenous EZH2 and SUZ12 loci and single-particle tracking revealed that ∼80% of PRC2 rapidly diffuses through the nucleus, while ∼20% is chromatin-bound. Short-term treatment with a small molecule inhibitor of the EED-H3K27me3 interaction had no immediate effect on the chromatin residence time of PRC2. In contrast, separation-of-function mutants of SUZ12, which still form the core PRC2 complex but cannot bind accessory proteins, revealed a major contribution of AEBP2 and PCL homolog proteins to chromatin binding. We therefore quantified the dynamics of this chromatin-modifying complex in living cells and separated the contributions of H3K27me3 histone marks and various PRC2 subunits to recruitment of PRC2 to chromatin.


Assuntos
Cromatina/metabolismo , Proteínas do Grupo Polycomb/metabolismo , Subunidades Proteicas/metabolismo , Linhagem Celular Tumoral , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Edição de Genes , Células HEK293 , Humanos , Indanos/farmacologia , Complexo Repressor Polycomb 2/genética , Complexo Repressor Polycomb 2/metabolismo , Proteínas do Grupo Polycomb/antagonistas & inibidores , Ligação Proteica/efeitos dos fármacos , Proteínas Recombinantes de Fusão/metabolismo , Sulfonamidas/farmacologia
16.
Development ; 145(14)2018 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-29945864

RESUMO

Epigenetic regulation of gene expression has a crucial role allowing for the self-renewal and differentiation of stem and progenitor populations during organogenesis. The mammalian kidney maintains a population of self-renewing stem cells that differentiate to give rise to thousands of nephrons, which are the functional units that carry out filtration to maintain physiological homeostasis. The polycomb repressive complex 2 (PRC2) epigenetically represses gene expression during development by placing the H3K27me3 mark on histone H3 at promoter and enhancer sites, resulting in gene silencing. To understand the role of PRC2 in nephron differentiation, we conditionally inactivated the Eed gene, which encodes a nonredundant component of the PRC2 complex, in nephron progenitor cells. Resultant kidneys were smaller and showed premature loss of progenitor cells. The progenitors in Eed mutant mice that were induced to differentiate did not develop into properly formed nephrons. Lhx1, normally expressed in the renal vesicle, was overexpressed in kidneys of Eed mutant mice. Thus, PRC2 has a crucial role in suppressing the expression of genes that maintain the progenitor state, allowing nephron differentiation to proceed.


Assuntos
Diferenciação Celular/fisiologia , Epigênese Genética/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Néfrons/embriologia , Complexo Repressor Polycomb 2/biossíntese , Células-Tronco/metabolismo , Animais , Proteínas com Homeodomínio LIM/biossíntese , Proteínas com Homeodomínio LIM/genética , Camundongos , Camundongos Transgênicos , Mutação , Néfrons/citologia , Complexo Repressor Polycomb 2/genética , Células-Tronco/citologia , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética
17.
Trends Biochem Sci ; 43(7): 487-489, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29731341

RESUMO

Polycomb repressive complex 2 (PRC2) is a chief epigenetic regulator. In a new article, Chen et al. describe the crystal structure of the heterotetrameric PRC2 holo complex, which provides important mechanistic insights into the organization of its subunits and the association of PRC2 with chromatin.


Assuntos
Cromatina , Complexo Repressor Polycomb 2/genética , Histonas/genética , Proteínas Repressoras/genética
18.
Cancer Sci ; 109(8): 2342-2348, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29845708

RESUMO

Polycomb group (PcG) proteins regulate the expression of target genes by modulating histone modifications and are representative epigenetic regulators that maintain the stemness of embryonic and hematopoietic stem cells. Histone methyltransferases enhancer of zeste homolog 1 and 2 (EZH1/2), which are subunits of polycomb repressive complexes (PRC), are recurrently mutated or highly expressed in many hematological malignancies. EZH2 has a dual function in tumorigenesis as an oncogene and tumor suppressor gene, and targeting PRC2, in particular EZH1/2, for anticancer therapy has been extensively developed in the clinical setting. Here, we review the oncogenic function of EZH1/2 and introduce new therapeutic drugs targeting these enzymes.


Assuntos
Proteína Potenciadora do Homólogo 2 de Zeste/genética , Neoplasias Hematológicas/genética , Oncogenes/genética , Complexo Repressor Polycomb 2/genética , Animais , Carcinogênese/genética , Humanos , Proteínas do Grupo Polycomb/genética
19.
Int J Surg Pathol ; 26(6): 525-527, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29623744

RESUMO

We highlight a rare variant pattern of low-grade endometrial stromal sarcoma showing extensive collagenous rosette formation, closely mimicking low-grade fibromyxoid sarcoma. Additionally, this neoplasm showed diffuse and strong expression of muscle markers, favoring an initial diagnosis of leiomyosarcoma. Reverse transcription-polymerase chain reaction showed the presence of JAZF1-SUZ12 fusion transcripts, and this highlights the broad morphologic and immunophenotypic spectrum of endometrial stromal sarcoma.


Assuntos
Neoplasias do Endométrio/diagnóstico , Tumores do Estroma Endometrial/diagnóstico , Fibrossarcoma/diagnóstico , Leiomiossarcoma/diagnóstico , Neoplasias Peritoneais/diagnóstico , Colectomia , Colo/patologia , Colo/cirurgia , Diagnóstico Diferencial , Neoplasias do Endométrio/genética , Neoplasias do Endométrio/patologia , Neoplasias do Endométrio/cirurgia , Tumores do Estroma Endometrial/patologia , Tumores do Estroma Endometrial/secundário , Tumores do Estroma Endometrial/cirurgia , Feminino , Fibrossarcoma/patologia , Fibrossarcoma/secundário , Fibrossarcoma/cirurgia , Humanos , Histerectomia , Leiomiossarcoma/patologia , Leiomiossarcoma/secundário , Leiomiossarcoma/cirurgia , Mesentério/patologia , Mesentério/cirurgia , Gradação de Tumores , Proteínas de Neoplasias/genética , Proteínas de Fusão Oncogênica , Neoplasias Peritoneais/patologia , Neoplasias Peritoneais/secundário , Neoplasias Peritoneais/cirurgia , Complexo Repressor Polycomb 2/genética
20.
Ann Hematol ; 97(7): 1193-1208, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29560522

RESUMO

Primary myelofibrosis (PMF) is one of the BCR/ABL-negative myeloproliferative neoplasms (MPNs), characterized by the diffuse fibrous hyperproliferation, bone marrow osteosclerosis, extramedullary hematopoiesis, and marked splenomegaly. The patients with PMF have an insidious onset, a long duration of clinical course, and the deteriorated quality of life. It has been reported that the CALR gene 9 exon mutations were detected in 25-30% PMF patients, particularly as high as 80% in the JAK2/MPL-negative ones. As the second most common mutation in BCR/ABL-negative MPNs, CALR mutation has been included in the latest World Health Organization (WHO) classification criteria as one of the main diagnostic criteria for both essential thrombocythemia (ET) and PMF. Moreover, the CALR mutations indicated a favorable prognosis, which the mechanism is still under investigation. It was demonstrated that a characterized high expression of EZH2 and SUZ12 in CALR-mutated patients. Taking EZH2 as the research entry point, we initially discussed the mechanism that the CALR-positive patients with PMF exhibited a better prognosis in the current study.


Assuntos
Calreticulina/genética , Proteína Potenciadora do Homólogo 2 de Zeste/biossíntese , Regulação Neoplásica da Expressão Gênica , Proteínas de Neoplasias/biossíntese , Mielofibrose Primária/genética , Adulto , Idoso , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Feminino , Células HEK293 , Células HL-60 , Humanos , Janus Quinase 2/genética , Masculino , MicroRNAs/biossíntese , MicroRNAs/sangue , MicroRNAs/genética , Pessoa de Meia-Idade , Mutação , Proteínas de Neoplasias/genética , Complexo Repressor Polycomb 2/biossíntese , Complexo Repressor Polycomb 2/genética , Mielofibrose Primária/metabolismo , Prognóstico , Interferência de RNA , RNA Neoplásico/biossíntese , RNA Neoplásico/sangue , RNA Neoplásico/genética , Proteínas Recombinantes/metabolismo , Transdução Genética
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