Enhancer of zeste homolog 2(EZH2) is a histone methyltransferase which regulate gene expression through epigenetic machinery. The abnormal expression of EZH2 has been described in many cancer types. With in-depth study, it was found that EZH2 is involved in the occurrence and development in many kinds of malignant hematologic disease which may play a dual role of oncogenes and tumor suppressor genes. In recent years, the emergence of EZH2 inhibitors provide a new option for the future treatment of hematological malignancies. In this review, the expression and clinical significance of EZH2 in various of hematological tumors were summarized briefly.
Enhancer of Zeste Homolog 2 Protein/genetics* ; Hematologic Neoplasms/genetics* ; Humans ; Neoplasms ; Oncogenes ; Research

Adult ; Enhancer of Zeste Homolog 2 Protein ; Female ; Humans ; Leukemia, Myeloid, Acute ; genetics ; Male ; MicroRNAs ; genetics ; Polycomb Repressive Complex 2 ; genetics

OBJECTIVE: To investigate the expression of miR-101 and EZH2 in patients with mantle cell lymphoma(MCL) and to analyze its correlation with clinical prognosis of MCL patients. METHODS: RQ-PCR and S-P immunohistochemistry were used to detect the expressions of miR-101 and EZH2 in tissue of MCL patients. CCK-8 was used to assay the effect of miR-100 minics on the proliferation of Jeko-1 and Mino cells; the flow cytometry with Annexin V/PI double staining was used to assay the apoptosis; Western blot was used to assay the effect of miR-101 minics on the expression of EZH2 protein in Jeko-1 and Mino cells. RESULTS: Compared with control group, miR-101 lowly expressed, and EZH2 protein highly expressed in MCL group, with very statistically significant difference(P<0.01).There was negative correlation between miR-101 and EZH2 expression(r=-0.638，P<0.05). The expression of miR-101 and EZH2 significantly correlated with B symptoms, International Prognostic Index(IPI) and Ann Arbor stage, respectively. Survival analysis showed that the overall survival(OS) rate of patients with low expression of miR-101 were significantly lower than that of patients with high miR-101 expression (P=0.0014), the OS rate of patients with EZH2 high expression were significantly lower than that of patients with EZH2 low expression (P=0.0093). The miR-100 minics could inhibit the proliferation of Jeko-1 and Mino cells, and increase the apoptotic rate. The expression of EZH2 protein was markedly suppressed by the miR-100 minics. CONCLUSION The expression of miR-101 and EZH2 is different in MCL patients with different clinical stage and prognosis. The miR-101 can inhibit the cell proliferation and induce cell apoptosis of mantle cell lymphoma by targeting EZH2.
Apoptosis ; Cell Proliferation ; Enhancer of Zeste Homolog 2 Protein ; genetics ; Humans ; Lymphoma, Mantle-Cell ; genetics ; MicroRNAs ; genetics ; Prognosis

The histone methyltransferase enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2)-mediated trimethylation of histone H3 lysine 27 (H3K27me3) regulates neural stem cell proliferation and fate specificity through silencing different gene sets in the central nervous system. Here, we explored the function of EZH2 in early post-mitotic neurons by generating a neuron-specific Ezh2 conditional knockout mouse line. The results showed that a lack of neuronal EZH2 led to delayed neuronal migration, more complex dendritic arborization, and increased dendritic spine density. Transcriptome analysis revealed that neuronal EZH2-regulated genes are related to neuronal morphogenesis. In particular, the gene encoding p21-activated kinase 3 (Pak3) was identified as a target gene suppressed by EZH2 and H3K27me3, and expression of the dominant negative Pak3 reversed Ezh2 knockout-induced higher dendritic spine density. Finally, the lack of neuronal EZH2 resulted in impaired memory behaviors in adult mice. Our results demonstrated that neuronal EZH2 acts to control multiple steps of neuronal morphogenesis during development, and has long-lasting effects on cognitive function in adult mice.
Animals ; Mice ; Enhancer of Zeste Homolog 2 Protein/metabolism* ; Histone Methyltransferases/metabolism* ; Histones/genetics* ; Morphogenesis ; Neuronal Plasticity ; Neurons/metabolism*

OBJECTIVETo screen novel miRNAs targeting EZH2 3' untranslated region (UTR) in recombinational MCF-7 breast cancer cells over-expressing EZH2 3' UTR and quantitative analyze the expressions of the screened miRNA in breast cancer cells and tissues.

METHODSA lentiviral library was transfected into the recombinant cell line MCF-7. The cells were screened with cytotoxic agents before extraction of the genome for amplification of the miRNA precursors using PCR. The screened miRNAs were identified with sequence analysis and their expressions were analyzed quantitatively with real-time PCR in breast cancer cells and tissues.

RESULTSSeven miRNAs were screened from the recombinant MCF-7 cells, namely miR-15b, miR-16-2, miR-181b2, miR-217, miR-224, miR-329-1, and miR-487b, all of which failed to be predicted by bioinformatics software. Real-time PCR showed that miR-217, miR-329-1, and miR-487b were over-expressed in MCF-7 cells, and the expression of miR-15b and miR-16-2 was significantly increased in cancer tissues compared with the adjacent tissues (P<0.05).

CONCLUSIONNovel targeted miRNAs that can not be predicted by bioinformatics software were successfully screened from MCF-7 breast cancer cells over-expressing EZH2 3' UTR. These miRNAs are expressed differentially between normal breast cells and breast cancer tissues.

3' Untranslated Regions ; Breast Neoplasms ; genetics ; Cell Line, Tumor ; Enhancer of Zeste Homolog 2 Protein ; Female ; Gene Expression Profiling ; Humans ; Lentivirus ; genetics ; MicroRNAs ; genetics ; Polycomb Repressive Complex 2 ; genetics

OBJECTIVEThis article aimed to review the biological characteristics of enhancer of zests homolog 2 (EZH2), and the transcriptional repression mechanism of action of EZH2 in tumors, particularly in the progression of lymphoma.

DATA SOURCESThe data cited in this review were mainly obtained from the articles listed in PubMed and HighWare that were published from March 2004 to April 2012. The search terms were "enhancer of zests homolog 2", "polycomb group", and "lymphoma".

STUDY SELECTIONArticles regarding the mechanism of EZH2 in post-transcriptional modification, functions of polycomb group proteins, and the roles of EZH2 in lymphoma were selected.

RESULTSEZH2 acts as oncogene and involved in many kinds of tumors. Moreover, it plays an important role in tumorigenesis and lymphomagenesis by promoting the proliferation and aggressiveness of neoplastic cells, facilitating malignant tumor cell diffusion, and mediating transcriptional silencing.

CONCLUSIONEZH2 mediated transcriptional repression through its methyltransferase activity at the chromatin level has certain influence on lymphoma, and there might exist a therapeutic window for the development of new agents and identification of novel diagnostic markers based on EZH2.

Disease Progression ; Enhancer of Zeste Homolog 2 Protein ; Epigenesis, Genetic ; Histones ; metabolism ; Humans ; Lymphoma ; etiology ; genetics ; Methylation ; Mutation ; Polycomb Repressive Complex 2 ; genetics ; physiology

Epigenetic alterations are associated with all aspects of cancer, from tumor initiation to cancer progression and metastasis. It is now well understood that both losses and gains of DNA methylation as well as altered chromatin organization contribute significantly to cancer-associated phenotypes. More recently, new sequencing technologies have allowed the identification of driver mutations in epigenetic regulators, providing a mechanistic link between the cancer epigenome and genetic alterations. Oncogenic activating mutations are now known to occur in a number of epigenetic modifiers (i.e. IDH1/2, EZH2, DNMT3A), pinpointing epigenetic pathways that are involved in tumorigenesis. Similarly, investigations into the role of inactivating mutations in chromatin modifiers (i.e. KDM6A, CREBBP/EP300, SMARCB1) implicate many of these genes as tumor suppressors. Intriguingly, a number of neoplasms are defined by a plethora of mutations in epigenetic regulators, including renal, bladder, and adenoid cystic carcinomas. Particularly striking is the discovery of frequent histone H3.3 mutations in pediatric glioma, a particularly aggressive neoplasm that has long remained poorly understood. Cancer epigenetics is a relatively new, promising frontier with much potential for improving cancer outcomes. Already, therapies such as 5-azacytidine and decitabine have proven that targeting epigenetic alterations in cancer can lead to tangible benefits. Understanding how genetic alterations give rise to the cancer epigenome will offer new possibilities for developing better prognostic and therapeutic strategies.
Chromatin ; metabolism ; Chromatin Assembly and Disassembly ; DNA Methylation ; Enhancer of Zeste Homolog 2 Protein ; Epigenesis, Genetic ; Histones ; metabolism ; Humans ; Neoplasms ; genetics ; metabolism ; pathology ; Polycomb Repressive Complex 2 ; genetics ; metabolism

OBJECTIVE: To study the expression levels of glial cell line-derived neurotrophic factor family receptor α-1 (GFRα1) and enhancer of zeste homolog 2 (EZH2) in the intestinal tissue of children with Hirschsprung's disease (HSCR), as well as the role of EZH2 in the regulation of GFRα1 gene expression and the pathogenesis of HSCR. METHODS: The samples of colon tissue with spasm from 24 children with HSCR after radical treatment of HSCR were selected as the experimental group, and the samples of necrotized colon tissue from 18 children with neonatal necrotizing enterocolitis after surgical resection were selected as the control group. Real-time PCR and Western blot were used to measure the expression levels of GFRα1 and EZH2 in colon tissue in both groups. Human neuroblastoma SH-SY5Y cells were divided into an EZH2 over-expression group and a negative control group. The cells in the EZH2 over-expression group were transfected with pCMV6-EZH2 plasmid, and those in the negative control group were transfected with pCMV6 plasmid. The expression levels of EZH2 and GFRα1 were measured after transfection. RESULTS: Compared with the control group, the experimental group had significant reductions in the mRNA and protein expression levels of GFRα1 and EZH2 in colon tissue (P<0.05), and the protein expression of EZH2 was positively correlated with that of GFRα1 (r=0.606, P=0.002). Compared with the negative control group, the EZH2 over-expression group had significant increases in the expression levels of EZH2 and GFRα1 after SH-SY5Y cells were transfected with EZH2 over-expression plasmid (P<0.05). CONCLUSIONS Low expression of EZH2 in the colon tissue of children with HSCR may be one of the causes of inadequate expression of GFRα1 and onset of HSCR.
Child ; Colon ; Enhancer of Zeste Homolog 2 Protein ; genetics ; Glial Cell Line-Derived Neurotrophic Factor Receptors ; genetics ; Hirschsprung Disease ; genetics ; Humans ; Infant, Newborn ; RNA, Messenger

OBJECTIVETo investigate the effect of miRNA-101 on the expression of the enhancer of zeste homolog 2 (EXH2) in human androgen-independent prostated cancer LNCaP cells.

METHODSWe divided LNCaP cells into a blank control, a negative control, and a miRNA-l01 transfection group, constructed the vector by transfecting synthetic miRNA-101 mimics into the LNCaP cells, and evaluated the efficiency of transfection by fluorescence microscopy. Then we determined the expression level of EZH2 mRNA by qRT-PCR in the three groups of cells and that of the EZH2 protein in the negative control and transfection groups by Western blot.

RESULTSGreen fluorescence signals were observed in over 70% of the LNCaP cells in the transfection group after 24 hours of transfection. At 72 hours, the expression of miRNA-101 was significantly upregulated in the transfected cells (P < 0.01), that of EZH2 mRNA was remarkably lower in the transfection group (0.01 ± 0.10) than in the blank control (0.95 ± 0.40) and negative control (0.86 ± 0.30) groups (both P < 0.01), and that of the EZH2 protein was increased in the negative control but decreased in the transfection group with the extension of culture time.

CONCLUSIONmiRNA-101, with its inhibitory effect on the expression of EZH2 in LNCaP cells, is a potential biotherapeutic for prostate cancer.

Androgens ; Cell Line, Tumor ; Enhancer of Zeste Homolog 2 Protein ; Genetic Vectors ; Humans ; Male ; MicroRNAs ; physiology ; Polycomb Repressive Complex 2 ; genetics ; metabolism ; Prostatic Neoplasms ; metabolism ; RNA, Messenger ; metabolism ; Transfection

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(
Core Binding Factor Alpha 3 Subunit/genetics* ; Enhancer of Zeste Homolog 2 Protein/genetics* ; Humans ; Neoadjuvant Therapy ; Rectal Neoplasms/drug therapy* ; Transcription Factor 3