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Abstract The aim of this study was to evaluate the expression of the EZH2 protein and describe the clinical and microscopic characteristics of adenoid cystic carcinoma (ACC) and pleomorphic adenoma (PA). The study included 16 ACC cases and 12 PA. All ACC and PA cases were positive for EZH2 and the ACC samples showed significantly higher EZH2 expression. The clinical and microscopic covariates were described in relation to EZH2 staining in ACC samples. The highest mean values of EZH2 were observed in cases with local metastasis, recurrence, perineural invasion, and predominantly cribriform growth pattern without solid areas. EZH2 is a potential marker of malignancy.
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Fibrosis， a tumor-like lesion between benign tissue and malignant tumor， mostly occurs in the liver， kidney， heart， lung， bone marrow and other organs and tissues. It can affect almost every organ and eventually induce multiple organ failure and cancers， seriously endangering human life. It will be of great importance to prevent cancer if the disease can be opportunely blocked in the fibrotic stage. The pathogenesis of fibrosis is still not completely clear. It is of great clinical significance to study the occurrence， development， and mechanism of fibrosis as well as to screen new therapeutic targets. Enhancer of zeste homolog 2 （EZH2） is mainly located in the nucleus and involved in the formation of the polycomb repressive complex 2. EZH2 is a methyltransferase which makes the lysine on position 27 of histone H3 （H3K27me3） undergo trimethyl modification induces gene silencing through classical or nonclassical actions， so as to inhibit or activate transcription. EZH2 plays a critical role in cell growth， proliferation， differentiation， and apoptosis， which is regulated by different targets and signaling pathways. EZH2 regulates the transformation of myofibroblasts and participates in the fibrosis of multiple organs. Recent studies have shown that EZH2 plays a role in fibrosis-related pathophysiological processes such as epithelial-mesenchymal transition， oxidative stress， and inflammation. EZH2 as the target of fibrosis， EZH2 inhibitors， and EZH2-related traditional Chinese medicine （TCM） formula and active compounds have gradually become hot research directions. EZH2 may be a powerful target for organ fibrosis. Exploring the structure， function， and distribution of EZH2， the role of EZH2 in fibrosis， the EZH2 inhibitors， and TCM formulas and active components targeting EZH2 has great meanings. This paper reviews the research progress in EZH2 and fibrosis， providing new ideas for the diagnosis， treatment， and drug development of fibrosis.
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SUMMARY OBJECTIVE: Breast cancer is the most common malignancy in women. In the treatment of these patients, pathological complete response is defined as the absence of invasive cancer in breast or lymph node tissue after the completion of neoadjuvant chemotherapy. In this study, we aimed to investigate the relationship of enhancer of zeste homolog 2 and mucin 1 expressions with pathological complete response in patients with breast cancer receiving neoadjuvant chemotherapy. METHODS: A total of 151 patients were included in the study. Enhancer of zeste homolog 2 and mucin 1 expressions were evaluated in the biopsy materials pre-neoadjuvant chemotherapy and post-neoadjuvant chemotherapy surgical material, and their relationship with pathological complete response was investigated. RESULTS: The pathological complete response rates were significantly higher among the hormone receptor-negative patients, those with a high Ki-67 score, and patients with HER2-positive. Higher pathological complete response rates were obtained from patients with enhancer of zeste homolog 2 expression positivity pre-neoadjuvant chemotherapy. In addition, after neoadjuvant chemotherapy, enhancer of zeste homolog 2 expression was found to be completely negative in materials with pathological complete response; that is, in breast tissues considered to be tumor-free. While there was no significant relationship between mucin 1 expression and pathological complete response pre-neoadjuvant chemotherapy, mucin 1 expression was determined to significantly differ between the tissues with and without pathological complete response among the surgical materials examined. CONCLUSION: In our study investigating the relationship between enhancer of zeste homolog 2 and mucin 1 expression and pathological complete response in patients who received neoadjuvant chemotherapy, we found that enhancer of zeste homolog 2 expression could be used as a predictive marker for pathological complete response. However, mucin 1 expression was not associated with pathological complete response.
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The enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase, which is widely studied in histone methylation modification. It can promote epigenetic gene silencing and mediate the occurrence of tumors through a variety of regulatory mechanisms. The gain-of-function and loss-of-function mutations of EZH2 have been confirmed in many cancers. At present, with the extensive attention paid to the regulatory role of EZH2 in epigenetic mechanism, the exact way in which EZH2 imbalance affects the pathogenesis of hematologic malignancies remains to be clarified. This article reviews the pathogenetic role of EZH2 in hematological tumors, and hope to find new targets for the prevention and treatment of hematological tumors.
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Objective:To investigate the expression of enhancer of zeste homolog 2 (EZH2) and its relationship with clinicopathological characteristics and prognosis in patients with diffuse large B-cell lymphoma (DLBCL).Methods:The clinicopathological data of 106 DLBCL patients with detailed follow-up data in Shanxi Provincial Cancer Hospital from January 2009 to December 2018 were retrospectively analyzed, including 30 cases (28%) of germinal center B cell-1ike (GCB) and 76 cases (72%) of non-GCB; and 11 cases of reactive lymph nodes were selected as the control group. EnVision method was used to detect the expressions of EZH2 and c-myc. The correlation of the expressions of EZH2 and c-myc proteins was analyzed, and the association of EZH2 protein with clinicopathological characteristics, overall survival (OS) and progression-free survival (PFS) of patients was also analyzed.Results:The positive expression rates of EZH2 and c-myc proteins were 78.3% (83/106) and 48.1% (51/106), respectively, and neither was expressed in the control group. The positive expression rate of EZH2 protein in non-GCB was higher than that in GCB ( P < 0.01). The expression of EZH2 was correlated with clinical staging, serum lactic dehydrogenase (LDH) level and international prognostic index (IPI) score (all P < 0.01). EZH2 expression was positively correlated with the c-myc protein expression in GCB ( r = 0.74, P < 0.001). Moreover, OS and PFS of EZH2 negative in DLBCL were better than those of EZH2 positive (all P < 0.001). Conclusions:EZH2 overexpression is correlated with advanced clinical staging, increased serum LDH level, high IPI score and non-GCB phenotype. The high expression of EZH2 may be related to the high expression of c-myc, suggesting the poor prognosis of patients with DLBCL.
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As neoplasias de glândulas salivares apresentam comportamentos diferenciados, que não seguem os padrões clássicos das neoplasias benignas e malignas. A raridade de algumas destas lesões dificulta ainda mais o entendimento dos mecanismos envolvidos na etiopatogenia. Marcadores moleculares como a proteína EZH2 têm sido utilizados na investigação de alterações epigenéticas em diferentes neoplasias, auxiliando na definição do diagnóstico e prognóstico das lesões. O objetivo do presente trabalho é avaliar a expressão da proteína EZH2 e descrever as características clínicas e microscópicas de amostras de carcinoma adenoide cístico (CAC) e adenoma pleomórfico (AP) com ênfase na importância da definição da malignidade da lesão. A análise dos cortes microscópicos corados em Hematoxilina e Eosina dos casos de Adenoma pleomórfico mostraram células epiteliais e mioepiteliais glandulares dispostas em lençóis e estruturas ductiformes em meio a estroma variável. Os casos de Carcinoma adenoide cístico mostraram três padrões distintos de crescimento incluindo formações tubulares, cribriformes e sólidas. Todos os casos de AP e CAC foram positivos para reação imuno-histoquímica para EZH2. As amostras de CAC apresentaram expressão de EZH2 significativamente maior comparado ao AP. As covariáveis metástase em linfonodos, recorrência, padrão histológico, presença de áreas sólidas e invasão perineural foram descritas em relação à marcação de EZH2 em amostras de CAC. Dessa forma, os resultados do estudo melhoram o entendimento das características clínicas e histológicas do CAC, assim como sobre o comportamento das lesões. Além disso, a análise mostra que o EZH2 é um potencial marcador de malignidade e ressalta a importância da validação de marcadores moleculares de alterações epigenéticas.
Salivary gland neoplasms present different behaviors, which do not follow the classic patterns of benign and malignant neoplasms. The rarity of some of these lesions makes it even more difficult to understand the mechanisms involved in the etiopathogenesis. Molecular markers such as the EZH2 protein have been used to investigate epigenetic changes in different neoplasms, helping to define the diagnosis and prognosis of the lesions. The aim of the study was to evaluate the expression of the EZH2 protein and to describe the clinical and microscopic characteristics of adenoid cystic carcinoma (ACC) and pleomorphic adenoma (PA) which emphasizes the importance of defining the malignancy of the neoplasm. Histopathological analysis of PA cases showed myoepithelial and glandular epithelial cells arranged as duct-like structures and sheets intermingled in the variable stroma and ACC cases showed the three growth patterns, tubular, cribriform and solid forms. All ACC and PA cases were positive for EZH2, with diffuse nuclear staining in neoplastic cells. The ACC samples showed significantly higher EZH2 expression compared to the PA. The covariables nodal metastasis, recurrence, growth pattern, presence of solid areas and perineural invasion have been described in relation to EZH2 staining in ACC samples. The results of the study improve the understanding of the clinical and histological characteristics of ACC, as well as on the behavior of lesions. In addition, the analysis showed that EZH2 is a potential marker of malignancy and highlights the importance of validating molecular markers of epigenetic alterations.
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Salivary Gland Neoplasms , Immunohistochemistry , Carcinoma, Adenoid Cystic , Adenoma, Pleomorphic , Epigenomics , Enhancer of Zeste Homolog 2 ProteinABSTRACT
Objective To investigate the expression and correlation of Runt-related transcription factor 3(RUNX3)and enhancer of zeste homolog 2(EZH2)in rectal cancer,and to reveal the relationship between the expression of RUNX3 and EZH2 and the sensitivity of XELOX regimen to neoadjuvant chemotherapy in locally advanced rectal cancer patients. Methods The carcinoma and paracancerous tissues of 31 patients with rectal adenocarcinoma and no preoperative antitumor therapy were selected as cancer group and paracancer group,respectively.The relative mRNA levels of RUNX3 and EZH2 in the two groups were measured by real-time quantitative reverse transcription-polymerase chain reaction,and the protein levels were determined by immunohistochemical assay.The expression of RUNX3 and EZH2 was compared between cancer tissue and paracancerous tissue.The pre-treatment wax blocks of 26 patients with locally advanced rectal cancer who received 3 cycles of XELOX regimen as neoadjuvant chemotherapy before surgery were selected as the pre-neoadjuvant therapy group,and the postoperative pathological wax blocks were selected as the post-neoadjuvant treatment group.Tumor regression grade(TRG)was determined to evaluate the efficacy of neoadjuvant therapy.Immunohistochemical assay was used to detect the protein levels of RUNX3 and EZH2 in the two groups,and then the relationship between the expression patterns of the two proteins and the efficacy of neoadjuvant chemotherapy was analyzed. Results Compared with paracancerous tissue,the cancer tissue showed down-regulated mRNA level and reduced positive protein expression rate of RUNX3,while up-regulated mRNA level(
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Humans , Core Binding Factor Alpha 3 Subunit/genetics , Enhancer of Zeste Homolog 2 Protein/genetics , Neoadjuvant Therapy , Rectal Neoplasms/drug therapy , Transcription Factor 3ABSTRACT
Objective: Regulatory T cells (Tregs) are critical factors that impair antitumor immunity. Epstein–Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) is one of the most pathogenic factors in nasopharyngeal carcinoma (NPC). However, the role of EBV-encoded LMP1 in regulating Treg generation in NPC remains unclear. Materials and Methods: The in vitro stability of activated Tregs (aTregs) influenced by LMP1 was analyzed by flow cytometry. The inhibitory effects of LMP1-HONE1 antigen-induced aTregs on tumor-associated antigen (TAA)-specific T cells were analyzed in vitro and in vivo. Finally, the expression of LMP1, Foxp3, and enhancer of zeste homolog 2 (EZH2) were analyzed in samples from 86 NPC patients by immunohistochemistry and immunofluorescence. Results: LMP1 upregulated the expression of EZH2, which increased the stability of aTregs in vitro. EZH2 inhibitor, DZnep, depleted LMP1-HONE1 antigen-induced aTregs in vitro and led to potent TAA-specific T cell antitumor immunity in vivo. In NPC tissues, LMP1 expression level was positively correlated with the number of EZH2+ Tregs, which was positively correlated with clinical stage and overall survival. Conclusions: EZH2 is essential for maintaining the stability and inhibitory functions of aTregs that are induced by EBV-encoded LMP1 in NPC
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Epigenetic modification is one of the important causes for the occurrence and development of cancers.Enhancer of zeste homolog 2 (EZH2),as an important member of the epigenetic suppressor polycomb group (PcG),can tri-methylate lysine at amino acid position 27 of histone H3 gene,and participates in the regulation of cell cycle,cell aging and cell differentiation.Recently,overexpression or mutation of EZH2 has been detected in a variety of solid tumors and B-cell lymphomas.However,the expression status and action mechanism of EZH2 in some T-cell lymphomas are still unclear,and its action mechanisms in different tumors are not completely consistent,which need further study.
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@#[Abstract] Objective: To investigate the molecular mechanism of miR-143-3p regulating the proliferation, migration and invasion of colon cancer RKO cells via targeting enhancer of zeste homolog 2 (EZH2). Methods: A total of 40 pairs of colon cancer tissues and corresponding para-cancerous tissues resected in the First Affiliated Hospital of Kunming Medical University from March 2015 to July 2017 were collected for this study. In addition, colon cancer cell lines (COLO320, RKO and CL-11) and normal intestinal mucosa NCM460 cells were also collected. qPCR was applied to detect the expression level of miR-143-3p in colon cancer tissues and cell lines. miR-143-3p mimics, miR-143-3p inhibitor, EZH2 siRNA and negative control plasmids were transfected into RKO cells, respectively. The effect of miR-143-3p/EZH2 axis on the proliferation, migration and invasion of RKO cells were detected by CCK-8 and Transwell assay, respectively. Western blotting was used to detect the expression level of EZH2 protein in RKO cells. The targeting relationship between miR-143-3p and EZH2 was verified by Dual luciferase reporter gene assay. Results: The expression level of miR-143-3p was downregulated in colon cancer tissues and cell lines (all P<0.01). Overexpression of miR-143-3p significantly inhibited the proliferation, migration and invasion of RKO cells (all P<0.01). Dual luciferase reporter gene assay confirmed that EZH2 was a target gene of miR-143-3p. Simultaneous knockdown of miR-143-3p and EZH2 attenuated the inhibition of EZH2 knockdown on the proliferation, migration and invasion of RKO cells. Conclusion: miR-143-3p suppresses the proliferation, migration and invasion of colon cancer cells via targetedly down-regulating EZH2.
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Epigenetic modification is one of the important causes for the occurrence and development of cancers. Enhancer of zeste homolog 2 (EZH2) , as an important member of the epigenetic suppressor polycomb group (PcG) , can tri-methylate lysine at amino acid position 27 of histone H3 gene, and participates in the regulation of cell cycle, cell aging and cell differentiation. Recently, overexpression or mutation of EZH2 has been detected in a variety of solid tumors and B-cell lymphomas. However, the expression status and action mechanism of EZH2 in some T-cell lymphomas are still unclear, and its action mechanisms in different tumors are not completely consistent, which need further study.
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@#Objective: To explore the mechanism of lncRNA XIST (XIST) regulating the biological behaviors of colorectal cancer HCT-8 cells via miR-32-5p/EZH2 (enhancer of Zeste homolog 2) axis. Methods:Atotal of 28 pairs of cancer tissues and corresponding para-cancerous tissues form colorectal cancer patients with complete clinical data were collected from the Colorectal and Anal Surgery, Xiangya Hospital of Central South University during July 2014 and August 2018. The expression levels of lncRNA XIST and miR-325p in colorectal cancer tissues and cell lines were detected by qPCR. The targeted relationship between lncRNA XIST, miR-32-5p and EZH2 was verified by dual luciferase reporter gene, and the expression level of EZH2 was further detected by WB. The proliferation, migration and apoptosis of HCT-8 cells were detected by CCK-8, Transwell and flow cytometry with Annexin V-FITC/PI staining, respectively. Results: lncRNAXIST was highly expressed in colorectal cancer tissues and cell lines with the highest expression in HCT-8 cells (P<0.05 or P<0.01). Dual luciferase reporter gene assay validated that lncRNA XIST negatively regulated miR-32-5p (P<0.05), and EZH2 was a target gene of miR-32-5p. Knockdown of lncRNAXIST inhibited proliferation and migration and induced apoptosis of HCT-8 cells (P<0.05 or P<0.01). Further experiments demonstrated that knockdown of lncRNA XIST up-regulated the expression of miR-32-5p and further down-regulated the expression level of EZH2, thereby inhibiting the proliferation and migration of HCT-8 cells and inducing apoptosis. Conclusion: lncRNAXIST promotes proliferation, migration and inhibits apoptosis of HCT-8 cells via miR-325p/EZH2 axis.
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Objective To investigate the expression of long non-coding RNA H19 (LncRNA H19)and its regulation of histone methyltransferase 2 (enhancer of zeste homolog 2,EZH2) in the lung tissue of neonatal rats with bronchopulmonary dysplasia (BPD),and to lay a foundation for elucidating the pathogenesis of BPD lung epithelium-interstitial transformation (EMT).Methods The BPD model of SD neonatal rats was induced by hyperoxia (inhalation oxygen concentration was 85％) (n =50),and oxygen inhalation concentration of the control group was 21％ (n =50).The two groups were collected at ld,3d,7d,14d and 21d after birth in lung tissue.Immunohistochemistry,Western blot,real-time quantitative PCR and other techniques were used to detect the intracellular localization,and the expression level of EZH2 protein and the mRNA expression level of H19 and EZH2.Results Immunohistochemistry showed that EZH2 protein was located in the nucleus and cytoplasm of alveolar epithelial cells,and the expression of EZH2 protein in the model group was significantly enhanced compared with the control group.Similarly,the results of Western blot demonstrated that the expression of EZH2 protein in the model group increased from ld (control group:0.196 ± 0.030,model group 0.650 ±0.149) to 21d (control group 0.934 ± 0.215,model group 1.785 ± 0.298) rather than the control group (P ＜ 0.05).Compared with the control group,the mRNA expression level of H19 in the model group increased from 7d (control group 2.591 ± 0.211,model group 3.558 ± 0.093,P ＜ 0.05) and the expression level of EZH2 mRNA started to increase from 3d (control group 1.246 ±0.015,model group 2.148 ± 0.215,P ＜0.05).Moreover,the differences between the two groups were obvious with the time of hyperoxia exposure.Conclusion In the development of BPD,the expression levels of H19 and EZH2 protein in lung tissue is up-regulated,and the peak of H19 expression precedes EZH2,which suggest that H19 might be involved in the pathogenesis of pulmonary dysplasia induced by EZH2-mediated EMT.
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Objective To investigate the effects of a novel enhancer of Zeste homolog 2 (EZH2) inhibitor GSK126 in vitro on the cell proliferation and apoptosis in acute leukemia and lymphoma cells. Methods CCKˉ8 assay was used to measure the effects of GSK126 with different concentrations and time on the cell proliferation in human Tˉcell acute lymphoblastic leukemia (TˉALL) CEM cell line, acute monocytic leukemia U937 cell line and Burkitt lymphoma Raji cell line. Annexin V/PI double staining method was used to determine the effects of GSK126 on the cell apoptosis. The effect of GSK126 on the mRNA levels of EZH2, bclˉ2 and bclˉxL were measured by using quantitative polymerase chain reaction (qPCR). Results After the function for 24 h, 48 h and 72 h, compared to the negative control group (0 μmol/L), 5, 10, 15, 20, 25 μmol/L GSK126 treatment showed a significant doseˉand timeˉdependent cell proliferation suppression in CEM cells; 5, 10, 15, 20 μmol/L GSK126 treatment showed a significant doseˉand timeˉdependent cell proliferation suppression in U937 cells; 5, 10, 15, 20, 25, 30 μmol/L GSK126 treatment showed a significant timeˉdependent suppression in Raji cells (all P< 0.05). The 48 h 50% inhibitory concentration ( IC 50) of GSK126 on CEM, U937, Raji cells was (13.46 ±0.83), (11.65 ±1.02), (15.00 ±0.19) μmol/L, respectively. GSK126 treatment with the doses of 8, 12 and 16 μmol/L promoted the apoptosis of CEM and U937 cells compared with the negative control group (0 μmol/L), and there were statistical differences in the apoptosis rate (F＝ 167.995, P< 0.01; F＝ 158.400, P< 0.01). In Raji cells, only 16 μmol/L GSK126 treatment had a higher cell apoptosis rate compared with the control group (t＝ 47.998, P< 0.05). Furthermore, 8, 12 and 16 μmol/L GSK126 treatment suppressed the expressions of EZH2 mRNA in CEM, U937 and Raji cells compared with the control group (F＝82.035, P<0.01; F＝ 252.712, P< 0.01; F＝ 690.536, P< 0.01), and the expressions of bclˉ2 and bclˉxL mRNA (bclˉ2: F＝ 1 900.525, P< 0.01; F＝ 431.324, P< 0.01; F＝216.184, P<0.01; bclˉxL: F＝256.751, P<0.01; F＝147.019, P<0.01; F＝209.325, P<0.01). Conclusion EZH2 plays an important role in the occurrence and development of acute leukemia and lymphoma. GSK126 as a high selective inhibitor of EZH2 might be a potential new drug in treatment of hematological malignancies.
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Objective: To detect the expressions of enhancers of zeste homolog 2 (EZH2), matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in hepatocellular carcinoma (HCC) tissues, analyze the correlation of EZH2, MMP-2 and MMP-9 expressions in HCC tissues with the clinicopathological factors of HCC to explore the role of EZH2 in the invasion and migration of HCC cells and the regulatory effects of EZH2 on MMP-2 and MMP-9. Methods: The expressions of EZH2, MMP-2 and MMP-9 in HCC tissues was detected by qRT-PCR. We analyzed the relationship of EZH2, MMP-2 and MMP-9 with the clinicopathological factors of HCC. Pearson correlation was used to analyze the correlation between EZH2, MMP-2 and MMP-9 expressions in HCC tissues. SMMC-7721 HCC cell lines with down-regulated EZH2 expression were constructed by small interfering RNA transfection. Transwell assay was used to observe the effects of EZH2 on invasion and migration of SMMC-7721 cells. qRT-PCR was used to detect the regulatory effects of EZH2 on MMP-2 and MMP-9 in HCC cells. Results: EZH2, MMP-2 and MMP-9 expressions were increased in HCC tissues, and they were correlated with adverse clinicopathological factors. There was a significant correlation between the expressions of EZH2 and MMP-9 in HCC tissues. Deletion of EZH2 significantly inhibited the invasion and migration of HCC cells and inhibited MMP-9 expression in HCC cells. Conclusion: EZH2, MMP-2 and MMP-9 are all closely associated with HCC progression, and they can be potential biomarkers and therapeutic targets for HCC.
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Objective To study on the role of histone methylation enzyme enhancer of zeste homolog 2 (EHZ2) and vascular endothelial growth factor 165 (VEGF165) in momymoya disease. Methods The animal model of moyamoya disease was established by ear vein injection of horse serum in New Zealand rabbits. VEGF165 was over-expressed in situ by packaging lentivirus. Real-time quantitative PCR and Western Blot were used to detect the expression of VEGF165, EZH2 and H3K27me3 in the brain tissues of the animal models. Results Compared with the normal control group, the expression levels of mRNA and protein of EZH2 in the moyamoya disease model group were increased (EZH2 mRNA:P<0.01), and the level of histone H3K27me3 was increased. After overexpression of VEGF165 in the moyamoya disease model group, the expression levels of mRNA and protein of EZH2 was further increased (EZH2 mRNA: P<0.01), and the level of histone H3K27me3 was also increased. Conclusions EZH2 plays a certain role in the pathogenesis of moyamoya disease, and the expression of EZH2 is regulated by VEGF 165, which provides a theoretical basis for the study of the pathogenesis of moyamoya disease.
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O lincRNA PVT1 (Plasmacytoma Variant Translocation 1) é um RNA longo não codificador de proteínas (ncRNA) descrito como um oncogene sendo superexpresso em vários tipos de cânceres. LincRNA PVT1 está localizado na região genômica 8q24, também conhecida como 'gene desert'. O nível de expressão do lincRNA PVT1 está associado ao aumento do risco de câncer de próstata (PCa) e está correlacionado com os níveis de expressão do receptor de andrógeno (AR). No entanto, o mecanismo do envolvimento do lincRNA PVT1 com o AR no desenvolvimento de câncer de próstata ainda não está bem esclarecido. Aqui, nós testamos a hipótese que a formação do complexo AR-EZH2-PVT1 participa na regulação da expressão gênica em câncer de próstata, nas células LNCaP. A imunoprecipitação de ribonucleoproteínas seguida de PCR quantitativo (RIP-qPCR) revelou que o lincRNA PVT1 está associado fisicamente ao AR (12% do input) e à metiltransferase EZH2, proteína componente do complexo repressor Polycomb 2 (36% do input) sob condições suplementadas com andrógeno (+R1881). O lincRNA PVT1 também está associado fisicamente ao AR (10% de input) e à EZH2 (42% de input) em condições de privação de andrógeno (-R1881). Assim, a associação física entre lincRNA PVT1, AR e EZH2 é independente do hormônio andrógeno. Usando uma abordagem de estudo em larga-escala de perda e ganho de função, nossos resultados mostraram que o silenciamento do lincRNA PVT1 em células LNCaP na presença de andrógeno restaura a expressão parcialmente, totalmente ou causa superexpressão de 160 genes que tiveram a expressão inibida por andrógeno. Entre esses genes, destacamos genes envolvidos na regulação da diferenciação celular, em componentes da junção célula-célula, na inibição da migração e invasão celular e no desencadeamento da via apoptótica. Imunoprecipitação da cromatina seguida de PCR quantitativo (ChIP-qPCR), em cultura de células LNCaP suplementada com andrógeno sob silenciamento do lincRNA PVT1, mostrou aumento significativo na ocupação pela marca de histona ativadora H3K27Ac do promotor do gene NOV, um dos genes que tiveram sua expressão aumentada com o silenciamento de PVT1. O ChIP-qPCR também mostrou, após o silenciamento do lincRNA PVT1, um aumento significativo da marca H3K27me3 na região enhancer do gene NOV, uma característica de enhancers poised (prontos para ativação). Em conclusão, nós fornecemos a primeira evidência experimental para um mecanismo de ação do oncogene lincRNA PVT1 em células de câncer de próstata e demonstramos que sua ação inibidora da expressão afeta genes alvo que facilitam a proliferação e migração de células do câncer de próstata, sugerindo que o lincRNA PVT1 é um novo agente no complexo mecanismo de repressão transcricional envolvendo um RNA silenciador, o receptor de andrógeno (AR) e o potenciador de Zeste homólogo 2 (EZH2) no remodelamento da cromatina em células LNCaP
Long non-coding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) is an oncogene known to be overexpressed in various types of cancer. PVT1 lincRNA is located in the wellknown cancer-related genomic region 8q24, also known as 'gene desert. PVT1 lincRNA level of expression is associated with increased prostate cancer (PCa) risk and is correlated with androgen receptor (AR) expression levels. However, the mechanism of PVT1 and AR involvement in the development of prostate cancer is still unclear. Here, we tested the hypothesis that formation of the complex AR-EZH2-PVT1 participates in the regulation of gene expression in prostate cancer, in LNCaP cells. Ribonucleoprotein immunoprecipitation followed by quantitative PCR (RIP-qPCR) revealed that PVT1 lincRNA binds both the AR (12 % of PVT1 input) and the methyltransferase EZH2 from the Polycomb repressive complex 2 (36 % of input) under androgen-supplemented conditions (+R1881). PVT1 also binds both AR (10 % of input) and EZH2 (42 % of input) under androgen-deprived conditions (-R1881). Thus, PVT1 binding to AR and EZH2 is independent of the androgen hormone. Using a large-scale loss and gain of function approach, our results show that PVT1 knockdown (KD) in LNCaP in the presence of androgen restores the expression partially, fully or causes overexpression of 160 genes that are inhibited by androgen. Among these genes, we highlight genes involved in regulation of cell differentiation, in components of cell-cell junction, in inhibition of cell migration and invasion and in triggering of the apoptotic pathway. Chromatin immunoprecipitation followed by quantitative PCR (ChIP-qPCR) with LNCaP cells in androgen-supplemented cultures under PVT1 lincRNA knockdown showed a significant increase in occupancy by the histone activation mark H3K27Ac of the promoter region of the NOV gene, one of the genes that had an increased expression upon PVT1 silencing. ChIPqPCR also showed a significant increase upon PVT1 lincRNA silencing of the H3K27me3 histone mark in the enhancer region of the NOV gene, a distinct feature of poised enhancers. In conclusion, we provide first experimental evidence for a mechanism of action of PVT1 lincRNA oncogene in prostate cancer cells, and show that its inhibitory action affects targetgenes that facilitate proliferation and migration of prostate cancer cells, thus suggesting PVT1 lincRNA as a novel lncRNA player in the complex mechanism of transcriptional repression involving a silencer RNA, the androgen receptor (AR) and the Enhancer of zeste homolog 2 (EZH2) in chromatin remodeling in LNCaP cells
Subject(s)
Plasmacytoma , RNA, Long Noncoding/adverse effects , Enhancer of Zeste Homolog 2 Protein/analysis , Androgens/analysis , Prostatic Neoplasms/diagnosisABSTRACT
Objective To investigate the effect of enhancer of zeste homolog 2 (EZH2) knockdown on chemosensitivity to oxaliplatin in human gastric cancer cell line SGC7901.Methods Small interfering RNA (siRNA) fragments were designed and synthesized for EZH2 mRNA sequence and divided into siRNA-1 group,siRNA-2 group and siRNA-3 group.They were transfected into gastric cancer cell line SGC7901.The negative control group and blank control group were set up at the same time.The expressions of EZH2 mRNA and protein in the SGC7901 cells were detected by quantitative real-time polyme-rase chain reaction (qRT-PCR) and Western blotting.CCK-8 assay was used to detect cell proliferation inhibition rates of SGC7901 cells treated by different concentrations of oxaliplatin.Results After transfection of EZH2 siRNA,the relative expression levels of EZH2 mRNA in siRNA-1 group,siRNA-2 group,siRNA-3 group were 0.615 ±0.190,0.241 ±0.152 and 0.450 ± 0.097.The relative expression levels of EZH2 mRNA of the three groups were lower than that in the negative control group (1.165 ± 0.376),and the differences were statistically significant (P =0.028;P =0.002;P =0.007).After transfection of the best siRNA fragment into SGC7901 gastric cancer cells,the relative expre-ssion levels of EZH2 protein in interference group,blank control group and negative control group were 0.036 ± 0.017,0.362 ± 0.026 and 0.398 ± 0.036,and the diffe-rence among the three groups was statistically significant (F =157.745,P ＜ 0.001).The difference between interference group and negative control group was statistically significant (P =0.001),as compared with the blank control group (P =0.002).When oxaliplatin concentration was 2,4,8 and 16 μg/ml,the differences of cell proliferation inhibition rate among interference group,negative control group and blank control group were statistically significant [(18.107 ± 2.822)％,(5.867±2.272)％,(5.333 ±1.883)％,F=28.185,P=0.001;(54.953 ±2.550)％,(22.177±1.871)％,(20.077±6.032)％,F=74.206,P＜0.001;(60.337±1.641)％,(34.597± 3.592)％,(30.227 ±5.273)％,F=54.897,P＜0.001;(78.340 ±2.081)％,(61.857 ±3.507)％,(63.077 ± 8.473) ％,F =8.586,P =0.017].There was no significant difference among groups of oxaliplatin at the concentration of 32 μg/ml [(83.450 ±3.715)％,(72.190 ±3.948)％,(70.731 ± 17.080)％,F=1.358,P =0.326].The median inhibitory concentration (IC50) of oxaliplatin in siRNA group,negative control group and blank control group were 5.178,12.643,13.601 μg/ml.Conclusion Down-regulation of EZH2 gene expression can significantly inhibit the proliferation of gastric cancer cells,and effectively enhance the sensitivity of gastric cancer cells to oxaliplatin,which indicates EZH2 may play important roles in the development of gastric cancer chemotherapy.These results provide an important theoretical basis for gene therapy of gastric cancer.
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@#[Abstract] Objective: To investigate the regulating effects of miR-92b on the expression of EZH2 (enhancer of zeste homolog 2) gene and the proliferation and invasion abilities of esophageal cancer (EC) cells. Methods: Fifteen cases of esophageal cancer tissues that preserved in the research center of the Fourth HospitalAffiliated to Heibei Medical University from January 2016 to January 2017 were selected for this study. The bioinformatics tool was used to predict the possible miRNAs that might target EZH2. The mimics of predicted miRNAs were transfected into human esophageal carcinoma cell lines Eca109, respectively. Then the regulation effect of miRNAs on EZH2 gene expression was validated by real-time PCR, Western blotting and dual luciferase reporter experiment. In the meanwhile, EZH2 over-expression plasmids were co-transfected into esophageal carcinoma Eca109 cells, and the effects of miRNAs and EZH2 expression changes on the proliferation, apoptosis , invasion and migration of esophageal carcinoma cells were detected by CCK-8 method, Flow Cytometry, Transwell Invasion and migration assay, respectively. Results: Bioinformatics analysis showed that miR-92b, let7a and miR-25 could combine with potential binding sites at 3’-terminal non-translation region of EZH2 gene. Real-time PCR results showed that only miR-92b was able to regulate the expression of EZH2, and miR-92b was negatively correlated to EZH2 in esophageal cancer (P<0.01). Compared with mimic-NC, the expression of EZH2 mRNA, protein and luciferase activity in Eca109 cells after miR-92b mimic transfection was significantly down-regulated (both P<0.01). However, miR-92b mimic transfection had no effect on the apoptosis of Eca109 cells. Moreover, the proliferation, invasion and migration of Eca109 cells were significantly inhibited after transfection with miR-92b-mimic (P<0.01). In addition, after co-transfection with EZH2 over-expression plasmids, the effects of miR-92b-mimic on the proliferation, invasion and migration of Eca109 cells were significantly weakened (P<0.01). Conclusion: miR-92b can inhibit the proliferation,invasionandmigrationofesophagealcarcinomacells,anditsmechanismmayberelatedtoitstargetregulationofEZH2. ··
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[Objective]To evaluate the expression of enhancer of zeste homolog 2(EZH2),Ki-67 and intratumoral microvaseu?lar density(iMVD)in human colorectal cancer(CRC),and discuss their relationship with the biological behavior and prognosis.[Methods]The expression of EZH2,Ki-67 and iMVD(labeled by CD34 protein)was measured with immunohistochemical MaxVision method in CRC patients followed up over 5 years.[Results]Positive expression rates of EZH2,Ki-67 and iMVD were 40.91%(45/110),57.27%(63/110)and 46.36%(51/110),respectively. EZH2 expression was positively correlated with distant metastasis(P=0.024). Ki-67 expression was positively correlated with tumor size,infiltration depth,AJCC stage and differentiation(P=0.033~0.015). The iMVD expression was positively correlated with infiltration depth ,AJCC stage and differentiation (P=0.016~0.034). Spearman correlation analysis showed that EZH2 expression was positively correlated with Ki-67 expression(r=0.195,P=0.041), whereas negatively correlated with iMVD expression. Ki-67 expression had a positive correlation with iMVD(r=0.213,P=0.025). Multivariate analysis suggested that the EZH2 expression was an adverse independent factor for survivals of CRC patients(HR 1.965, 95%CI:1.019-3.789,P=0.044 for OS).[Conclusion]EZH2 expression was significantly correlate with the proliferation of tumor cells and may plays an important role in the metastasis and prognosis of CRC.