Enhancer of zeste homolog 2 contributes to apoptosis by inactivating janus kinase 2/signal transducer and activator of transcription signaling in inflammatory bowel disease

BACKGROUND Inflammatory bowel disease(IBD)is a prevalent worldwide health problem featured by relapsing,chronic gastrointestinal inflammation.Enhancer of zeste homolog 2(EZH2)is a critical epigenetic regulator in different pathological models,such as cancer and inflammation.However,the role of EZH2 in the IBD development is still obscure.AIM To explore the effect of EZH2 on IBD progression and the underlying mechanism.METHODS The IBD mouse model was conducted by adding dextran sodium sulfate(DSS),and the effect of EZH2 on DSS-induced colitis was assessed in the model.The function of EZH2 in regulating apoptosis and permeability was evaluated by Annexin V-FITC Apoptosis Detection Kit,transepithelial electrical resistance analysis,and Western blot analysis of related markers,including Zona occludens 1,claudin-5,and occludin,in NCM460 and fetal human colon(FHC)cells.The mechanical investigation was performed by quantitative reverse transcriptionpolymerase chain reaction,Western blot analysis,and chromatin immunoprecipitation assays.RESULTS The colon length was inhibited in the DSS-treated mice and was enhanced by the EZH2 depletion in the system.DSS treatment caused a decreased histological score in the mice,which was reversed by EZH2 depletion.The inflammatory cytokines,such as tumor necrosis factor-α,interleukin-6,and interleukin-1β,were induced in the DSS-treated mice,in which the depletion of EZH2 could reverse this effect.Moreover,the tumor necrosis factor-αtreatment induced the apoptosis of NCM460 and FHC cells,in which EZH2 depletion could reverse this effect in the cells.Moreover,the depletion of EZH2 attenuated permeability of colonic epithelial cells.Mechanically,the depletion of EZH2 or EZH2 inhibitor GSK343 was able to enhance the expression and the phosphorylation of janus kinase 2(JK2)and signal transducer and activator of transcription in the NCM460 and FHC cells.Specifically,EZH2 inactivated JAK2 expression by regulating histone H3K27me3.JAK2 inhibitor TG101348 was able to reverse EZH2 knockdownmediated colonic epithelial cell permeability and apoptosis.CONCLUSION Thus,we concluded that EZH2 contributed to apoptosis and inflammatory response by inactivating JAK2/signal transducer and activator of transcription signaling in IBD.EZH2 may be applied as a potential target for IBD therapy.

EZH2 Contributes to Anoikis Resistance and Promotes Epithelial Ovarian Cancer Peritoneal Metastasis by Regulating m6A

Objective:Histone modification has a significant effect on gene expression.Enhancer of zeste homolog 2(EZH2)contributes to the epigenetic silencing of target chromatin through its roles as a histone-lysine N-methyltransferase enzyme.The development of anoikis resistance in tumor cells is considered to be a critical step in the metastatic process of primary malignant tumors.The purpose of this study was to investigate the effect and mechanism of anoikis resistance in ovarian adenocarcinoma peritoneal metastasis.Methods:In addition to examining EZH2 protein expression in ovarian cancer omental metastatic tissues,we established a model of ovarian cancer cell anoikis and a xenograft tumor model in nude mice.Anoikis resistance and ovarian cancer progression were tested after EZH2 and N6-methyladenosine(m6A)levels were modified.Results:EZH2 expression was significantly higher in ovarian cancer omental metastatic tissues than in normal ovarian tissues.Reducing the level of EZH2 decreased the level of m6A and ovarian cancer cell anoikis resistance in vitro and inhibited ovarian cancer progression in vivo.M6a regulation altered the effect of EZH2 on anoikis resistance.Conclusion:Our results indicate that EZH2 contributes to anoikis resistance and promotes ovarian adenocarcinoma abdominal metastasis by m6A modification.Our findings imply the potential of the clinical application of m6A and EZH2 for patients with ovarian cancer.

miR-124 is upregulated in diabetic mice and inhibits proliferation and promotes apoptosis of high-glucose-inducedβ-cells by targeting EZH2

BACKGROUND Diabetes is a chronic metabolic disease,and a variety of miRNA are involved in the occurrence and development of diabetes.In clinical studies,miR-124 is highly expressed in the serum of patients with diabetes and in pancreatic isletβ-cells.However,few reports exist concerning the role and mechanism of action of miR-124 in diabetes.AIM To investigate the expression of miR-124 in diabetic mice and the potential mechanism of action in isletβ-cells.METHODS The expression levels of miR-124 and enhancer of zeste homolog 2(EZH2)in pancreatic tissues of diabetic mice were detected.The targeted relationship between miR-124 and EZH2 was predicted by Targetscan software and verified by a double luciferase reporter assay.Mouse isletβ-cells Min6 were grown in a high glucose(HG)medium to mimic a diabetes model.The insulin secretion,proliferation,cell cycle and apoptosis of HG-induced Min6 cells were detected after interference of miR-124a and/or EZH2.RESULTS The expression of miR-124 was upregulated and EZH2 was downregulated in the pancreatic tissue of diabetic mice compared with control mice,and the expression of miR-124 was negatively correlated with that of EZH2.miR-124 was highly expressed in HG-induced Min6 cells.Inhibition of miR-124 promoted insulin secretion and cell proliferation,induced the transition from the G0/G1 phase to the S phase of the cell cycle,and inhibited cell apoptosis in HG-induced Min6 cells.EZH2 was one of the targets of miR-124.Co-transfection of miR-124 inhibitor and siRNA-EZH2 could reverse the effects of the miR-124 inhibitor in HG-induced Min6 cells.CONCLUSION miR-124 is highly expressed in diabetic mice and HG-induced Min6 cells and regulates insulin secretion,proliferation and apoptosis of isletβ-cells by targeting EZH2.

EZH2 is a biomarker associated with lung cancer diagnosis and immune infiltrates without prognostic specificity: a study based on the cancer genome atlas data

Enhancer of zeste homolog 2(EZH2)is the catalytic subunit of polycomb repressive complex 2(PRC2).Dysregulation of EZH2 causes alteration of gene expression and functions,thereby promoting cancer development.Recent studies suggest that EZH2 has a potential prognostic role in patients with nonsmall cell lung cancer(NSCLC).However,the prognostic value of EZH2 expression levels in NSCLC is controversial.In this study,we evaluated the prognostic value in lung cancer(LC-LUAD/LUSC)based on data from The Cancer Genome Atlas(TCGA)database.Kruskal-Wallis test,Wilcoxon signed-rank test,and logistic regression were used to evaluate the relationship between EZH2 expression and clinicopathological features.Cox regression and the Kaplan-Meier method were adopted to evaluate prognosis-related factors.Gene set enrichment analysis(GSEA)was performed to identify the key pathways related to EZH2.The correlations between EZH2 and cancer immune infiltrates were investigated by single-sample Gene Set Enrichment Analysis(ssGSEA).EZH2 was found to be up regulated with amplification in tumor tissues in multiple LC cohorts.High EZH2 expression was associated with poorer overall survival(OS).GSEA suggested that EZH2 regulates innate immune system,ECM affiliated,matrisome,surfactant metabolism.Notably,ssGSEA indicated that EZH2 expression was positively correlated with infiltrating levels of Th2 cells and significantly negatively correlated with mast cell infiltration level.These results suggest that EZH2 is associated with LC immune infiltration and significantly over-expressed in lung cancer,and its diagnostic value is better than prognosis,which lays a foundation for further study of the immunomodulatory role of EZH2 in LC.

EZH2 mediates mechanisms of AD20 on its inhibitory effects in PC3 cell proliferation and migration

OBJECTIVE Prostate cancer is the most commonly diagnosed malignancy and the sixth leading cause of cancer death in men.Aberrant upregulation of enhancer of Zeste homolog2(EZH2)occur frequently in human cancers,including prostate adenocarcinoma,it′s a bona fide oncogene,yet clinical benefits of EZH2 inhibitor(EZH2i)remain unsatis⁃factory and limited to certain hematological malignancies.AD20 is a natural product which is extracted from creosote bush.Our previous study has demonstrated that AD20 could inhibit the growth and metastasis in prostate cancer by inhibiting NRP1,however,the mechanisms still need to be clarified.METHODS PC3 cell were cultured in DMEM/F12 supplemented with 10%fetal bovine serum.The proliferation and migration were measured by MTS,wound healing assay and tran⁃swell assay.The expression of the protein was observed by Western blot.The mRNA levels were detected by real-time PCR.LC-MS/MS-based proteomic assay,CoIP-MS and network pharmacology are used to construct the PPI network and identify related proteins.RESULTS AD20(10-20μmol·L^-1)can regulate EZH2 expression from transcription,trans⁃lation,degradation levels.AD20 downregulates EZH2-H3K27me3 signaling dramatically and activates many down⁃stream tumor suppressor genes,such as CDH1,GATA6,CDKN2A.In vitro,AD20(10-40μmol·L^-1)suppresses PC3 cell proliferation and migration in a dose-dependent manner.And interestingly,the combination with AD20 significantly improved the efficacy of EZH2 inhibitors(GSK126 and EPZ-6438)in PC3 cell line.CONCLUSION AD20 can suppress PC3 cell proliferation by targeting EZH2-H3K27me3-p16INK4a signaling and inhibit PC3 cell migration by inhibiting NRP1.

Overexpression of enhancer of zests homolog 2 in lymphoma

Objective This 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 sources The 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 selection Articles regarding the mechanism of EZH2 in post-transcriptional modification, functions of polycomb group proteins, and the roles of EZH2 in lymphoma were selected. Results EZH2 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. Conclusion EZH2 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.