High Expression of EZH2 Mediated by ncRNAs Correlates with Poor Prognosis and Tumor Immune Infiltration of Hepatocellular Carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is the predominant form of liver cancer and is accompanied by a complex regulatory network. Increasing evidence suggests that an abnormal gene expression of EZH2 is associated with HCC progression. However, the molecular mechanism by which non-coding RNAs (ncRNAs) regulate EZH2 remains elusive. METHODS: The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) data were used to perform differential expression analysis and prognostic analysis. We used the Encyclopedia of RNA Interactomes (ENCORI) database to predict candidate miRNAs and lncRNAs that may bind to EZH2. Subsequently, the comprehensive analysis (including expression analysis, correlation analysis, and survival analysis) identified ncRNAs that contribute to EZH2 overexpression. RESULTS: EZH2 was found to be upregulated in the majority of tumor types and associated with a poor prognosis. Hsa-miR-101-3p was identified as a target miRNA of EZH2. Additionally, SNHG6 and MALAT1 were identified as upstream lncRNAs of hsa-miR-101-3p. Meanwhile, correlation analysis revealed that EZH2 expression was significantly associated with the infiltration of several immune cell types in HCC. CONCLUSION: SNHG6 or MALAT1/hsa-miR-101-3p/EZH2 axis were identified as potential regulatory pathways in the progression of HCC.

Long noncoding RNA SNHG6 promotes oesophageal squamous cell carcinoma by downregulating the miR-101-3p/EZH2 pathway.

Long noncoding RNAs (LncRNAs) have been reported to play a vital role in the development of oesophageal squamous cell carcinoma (OSCC). Our previous study revealed that the significant upregulation of the LncRNA small nucleolar RNA host gene 6 (SNHG6) in OSCC promotes OSCC tumourigenesis. However, the mechanisms underlying the dynamics of SNHG6 expression in OSCC have rarely been studied. In this study, we verified the tumour-promoting effect of SNHG6 through sponging miR-101-3p, and their levels were negatively correlated in human samples of OSCC. In addition, miR-101-3p overexpression reversed the effect of SNHG6. Moreover, we confirmed that SNHG6/miR-101-3p affects OSCC by regulating the expression of the enhancer of zeste 2 (EZH2). The effect of EZH2 silencing resembled closely that of SNHG6 knockdown. EZH2 silencing inhibited the expression of protein cyclin D1 and ß-catenin, but in contrast, it enhanced the expression of E-cadherin. These findings demonstrated the oncogenic role of SNHG6, which promotes OSCC progression by regulating the expression of EZH2 through its interaction with miR-101-3p. These findings may help in improving the diagnosis and treatment methods of OSCC.

MiR-137 inhibits the proliferation, invasion and migration of glioma via targeting to regulate EZH2.

BACKGROUND: Gliomas are common malignant tumors in the nervous system, known for poor prognosis and low survival rate. OBJECTIVE: This study aims to explore functions of miR-137 in glioma progression and identify messenger RNAs (mRNA) regulated by miR-137, which provides new ideas for further exploration of glioma therapeutic targets. METHODS: Gene expression data were downloaded from the Cancer Genome Atlas database, and abnormally expressed miRNAs and mRNAs in glioma were analyzed. The expression of genes in 20 pairs of clinical tissue samples and glioma cell lines were detected through qRT-PCR, and the expression of proteins was detected through Western blot. Changes in cell proliferative level after transfection were detected via CCK8 assay, and changes in cell migratory and invasive abilities were detected by Transwell assay. Besides, dual-luciferase reporter assay was employed to testify binding relationship between two genes. RESULTS: Our study found that miR-137 was significantly and lowly expressed in glioma tissue and cell lines, and the prognoses of glioma patients with highly expressed miR-137 were more optimistic. Overexpressed miR-137 could remarkably inhibit proliferative, invasive and migratory abilities of glioma cells U87, while transfection of miR-137 inhibitor presented an opposite effect. Additionally, EZH2 was a direct target of miR-137 and overexpressed EZH2 effectively reversed the effect of miR-137 on glioma proliferation and migration. CONCLUSIONS: Our study found that miR-137 could suppress the proliferation, invasion and migration of glioma cells through regulating the expression of EZH2. So far, we have found a novel regulatory pair that influences glioma progression, providing a basis for further development of new therapeutic strategies.

Serum-Derived Small Extracellular Vesicles From Diabetic Mice Impair Angiogenic Property of Microvascular Endothelial Cells: Role of EZH2.

Background Impaired angiogenic abilities of the microvascular endothelial cell (MVEC) play a crucial role in diabetes mellitus-impaired ischemic tissue repair. However, the underlying mechanisms of diabetes mellitus-impaired MVEC function remain unclear. We studied the role of serum-derived small extracellular vesicles (ssEVs) in diabetes mellitus-impaired MVEC function. Methods and Results ssEVs were isolated from 8-week-old male db/db and db/+ mice by ultracentrifugation and size/number were determined by the Nano-sight tracking system. Diabetic ssEVs significantly impaired tube formation and migration abilities of human MVECs. Furthermore, local transplantation of diabetic ssEVs strikingly reduced blood perfusion and capillary/arteriole density in ischemic hind limb of wildtype C57BL/6J mice. Diabetic ssEVs decreased secretion/expression of several pro-angiogenic factors in human MVECs. Mechanistically, expression of enhancer of zest homolog 2 (EZH2), the major methyltransferase responsible for catalyzing H3K27me3 (a transcription repressive maker), and H3K27me3 was increased in MVECs from db/db mice. Diabetic ssEVs increased EZH2 and H3K27me3 expression/activity in human MVECs. Expression of EZH2 mRNA was increased in diabetic ssEVs. EZH2-specific inhibitor significantly reversed diabetic ssEVs-enhanced expression of EZH2 and H3K27me3, impaired expression of angiogenic factors, and improved blood perfusion and vessel density in ischemic hind limb of C57BL/6J mice. Finally, EZH2 inactivation repressed diabetic ssEVs-induced H3K27me3 expression at promoter of pro-angiogenic genes. Conclusions Diabetic ssEVs impair the angiogenic property of MVECs via, at least partially, transferring EZH2 mRNA to MVECs, thus inducing the epigenetic mechanism involving EZH2-enhanced expression of H3K27me3 and consequent silencing of pro-angiogenic genes. Our findings unravel the cellular mechanism and expand the scope of bloodborne substances that impair MVEC function in diabetes mellitus.

Inhibition of enhancer of zeste homolog 2 prevents corneal myofibroblast transformation in vitro.

PURPOSE: Corneal fibroblast can be transformed into corneal myofibroblasts by TGF-ß1. Enhancer of zeste homolog 2 (EZH2) upregulation has been observed in the occurrence of other fibrotic disorders. We investigated the role of EZH2 in the progression of corneal fibrosis and the antifibrotic effect of EZH2 inhibition in corneal fibroblasts (CFs). METHODS: Primary CFs were isolated from corneal limbi and the CFs were treated with TGF-ß1 to induce fibrosis. EPZ-6438 and EZH2 siRNA were used to inhibit EZH2 expression. Myofibroblast activation and extracellular matrix (ECM) protein synthesis was detected by quantitative real-time PCR, western blotting, and immunofluorescence staining assay. The functions of myofibroblast were evaluated by cell migration and collagen gel contraction assays. Molecular mechanisms involved in EZH2 inhibition were investigated by RNA sequencing. RESULTS: TGF-ß1 activated EZH2 expression in CFs. Treatment with EPZ-6438 (5 µM) and EZH2 siRNA considerably suppressed corneal myofibroblast activation and ECM protein synthesis in CFs induced by TGF-ß1 when compared to the control group. EPZ-6438 (5 µM) suppressed cell migration and gel contraction in CFs. RNA sequencing results revealed that antifibrotic genes were activated after EZH2 inhibition to suppress corneal myofibroblast activation. CONCLUSION: Inhibition of EZH2 suppresses corneal myofibroblast activation and ECM protein synthesis, and could serve as a novel therapeutic target for preventing corneal scarring.

Upregulation of miR-138 Increases Sensitivity to Cisplatin in Hepatocellular Carcinoma by Regulating EZH2.

Chemotherapeutic insensitivity is a major obstacle for effective treatment of hepatocellular carcinoma (HCC). Recently, new evidence showed that microRNAs (miRNAs) are closely related to drug sensitivity. This study aimed to investigate the relationship between miR-138 expression and cisplatin sensitivity of HCC cells by regulation of EZH2. CCK-8, EdU, and western blotting are determining the cell viability, proliferation, EZH2, and EMT-related protein expression. It was found that compared with normal samples, miR-138 expression was lower in cancer tissue; it was also downregulated in HCC cells. Transfected with miR-138 mimic increased sensitivity of HCC cells to cisplatin. Mechanistically, Luciferase Reporter analysis verified the interaction between miR-138 and target gene EZH2. Inhibition of EZH2 enhanced cisplatin sensitivity and transfection with EZH2 mimic mirrored the function of miR-138 in cisplatin sensitivity. Furthermore, the role of miR-138 on reversed cisplatin-induced epithelial-mesenchymal transition (EMT) was attenuated when combined with EZH2 plasmid. In conclusion, all data from this study illustrate that miR-138 may as a tumor suppressor provides a potential treatment method to treating HCC.

Curcumin regulates EZH2/Wnt/ß-Catenin pathway in the mandible and femur of ovariectomized osteoporosis rats.

Osteoporosis (OP) behaves in different manners in different parts of the skeleton. This study aims to investigate the effects of curcumin on bone mass of the mandibular and femur from ovariectomized OP rats and to validate whether enhancer of zeste homolog 2 (EZH2)/Wnt/ß-Catenin pathway is involved in this process. Curcumin was administered intragastrically into ovariectomized rats for 12 weeks. The bone parameters and the morphology of the trabecular bone of the left mandible and left femur were assessed by micro-computed tomography assay. Morphological changes of the left mandible and left femur were evaluated by hematoxylin and eosin staining. The mRNA levels of EZH2, ß-Catenin, and Runx2 in the right mandible and right femur were examined by quantitative real-time polymerase chain reaction. Immunohistochemistry was performed to assess EZH2 expression. Both the mandible and femur exhibited OP-like changes in ovariectomized rats, while the mandible bone resorption was less than the femur bone resorption. Curcumin intragastric administration improved bone microstructure and promoted bone formation in the mandible and femur. Curcumin inhibited EZH2 mRNA level and induced that of ß-Catenin and Runx2 in the mandible and femur. Collectively, curcumin exerts protective effects against OP, possibly by regulating the EZH2/Wnt/ß-Catenin pathway.

High level of EZH2 expression is linked to high density of CD8-positive T-lymphocytes and an aggressive phenotype in renal cell carcinoma.

PURPOSE: Enhancer of zeste homolog 2 (EZH2), the catalytic part of the Polycomb repressive complex 2 (PRC2), has a prognostic role in renal cell carcinoma (RCC) and was recently shown to modulate the immune response by reducing tumor cell immunogenicity. METHODS: To investigate whether the prognostic role of EZH2 might be driven by a modified immune environment, more than 1800 RCCs were analyzed in a tissue microarray for EZH2 expression and CD8 positive lymphocytes were quantitated by automated digital imaging. RESULTS: EZH2 positivity was found in 75.2% of 1603 interpretable tumors. In clear cell RCC, high EZH2 expression was significantly linked to high ISUP, Furmann, and Thoenes grade (p < 0.0001 each), advanced stage (p < 0.0001), nodal (p = 0.0190) and distant metastasis (p < 0.0001) as well as shortened overall (p < 0.0027) and recurrence free survival (p < 0.0001). The density of CD8+ cells varied from 0 to 5048 cells/mm2 (Median 120 cells/mm2). A high CD8+ count was significantly associated with high ISUP, Fuhrmann, and Thoenes grade (p < 0.0001 each), advanced tumor stage (p = 0.0041), distant metastasis (p = 0.0026) as well as reduced overall survival (p = 0.0373) and recurrence free survival (p = 0.0450). The density of CD8+ cells continuously increased with raising EZH2 levels (p < 0.0001). CONCLUSION: Our data support a striking prognostic role of both EZH2 expression and the density of CD8+ cells in RCC. The tight relationship of EZH2 expression and CD8+ cell counts in RCC is consistent with models suggesting that EZH2 overexpression can be caused by high lymphocyte content in certain tumor types. Such a mechanism could explain the unique finding of high lymphocyte counts driving poor prognosis in RCC patients.

Differential Expression of EZH2 and H3K27me3 in Oral Verrucous Carcinoma and Oral Verrucous Hyperplasia.

Enhancer of zeste homolog 2 (EZH2), a component of the polycomb repressive complex 2 that catalyzes trimethylation of H3K27 (H3K27me3), has been shown to promote tumor development and progression. Expression of EZH2 is associated with cell cycle regulation and cell proliferation in various neoplasms. Oral verrucous hyperplasia (OVH) and Oral verrucous carcinoma (OVC) are rare entities and share several clinical and histopathologic features. Problems distinguishing these lesions are added by a lack of adjacent normal tissue of the biopsy samples and poorly oriented tissue sections. The aim of this study was to investigate the expression of EZH2 and H3K27me3 in OVH and OVC and comparing the expression with normal oral mucosa and oral squamous cell carcinoma (OSCC). Seventy-eight samples, including 25 cases of OVC, 8 cases of OVH, 35 cases of OSCC and 10 cases of normal oral mucosa, were retrieved and submitted for immunohistochemical staining. The results demonstrated that the mean labeling indices (LIs) of EZH2 and H3K27me3 expression were highest in OSCC, followed by the OVC, OVH, and normal mucosa. Statistical differences in EZH2 LI were observed among these lesions whereas H3K27me3 LI was significantly different among OSCC, OVH and normal mucosa. EZH2 LI was found to have a sensitivity of 72.00% and specificity of 87.50% in distinguishing OVH from OVC, and a sensitivity of 57.14% and specificity of 84.00% in distinguishing OVC from OSCC. A positive correlation between EZH2 and H3K27me3 expression was significantly found in OVC but not in OVH and OSCC. These findings highlight the involvement of epigenetic regulation by EZH2-mediated H3K27me3 in the pathogenesis of OVH and OVC, and EZH2 expression indicates disease progression of these verrucous lesions. Diagnostic test analysis further suggests that EZH2 may be used as an additional test for differentiating OVH from OVC in questionable cases.

Effect of EZH2 on pulmonary artery smooth muscle cell migration in pulmonary hypertension.

Pulmonary hypertension (PH) is a life­threatening disease that often involves vascular remodeling. Although pulmonary arterial smooth muscle cells (PASMCs) are the primary participants in vascular remodeling, their biological role is not entirely clear. The present study analyzed the role of enhancer of zeste homolog 2 (EZH2) in vascular remodeling of PH by investigating the behavior of PASMCs. The expression levels of EZH2 in PASMCs in chronic thromboembolic pulmonary hypertension (CTEPH), a type of PH, were detected. The role of EZH2 in PASMC migration was investigated by wound­healing assay following overexpression and knockdown. Functional enrichment analysis of the whole­genome expression profiles of PASMCs with EZH2 overexpression was performed using an mRNA Human Gene Expression Microarray. Quantitative (q)PCR was performed to confirm the results of the microarray. EZH2 expression levels increased in CTEPH cell models. The overexpression of EZH2 enhanced PASMC migration compared with control conditions. Functional enrichment analysis of the differentially expressed genes following EZH2 overexpression indicated a strong link between EZH2 and the immune inflammatory response and oxidoreductase activity in PASMCs. mRNA expression levels of superoxide dismutase 3 were verified by qPCR. The results suggested that EZH2 was involved in the migration of PASMCs in PH, and may serve as a potential target for the treatment of PH.

Expression and DNA methylation profiles of EZH2-target genes in plasma exosomes and matched primary tumor tissues of the patients with diffuse large B-cell lymphoma.

AIMS: Diffuse large B-cell lymphoma (DLBCL) is the most common type of aggressive lymphoma. This study was designed to compare epigenetic alterations observed in Enhancer of Zeste Homolog 2 (EZH2)-target genes between plasma-derived exosomes and primary tumors in DLBCL patients. MAIN METHODS: Exosomes were isolated from plasma of 21 DLBCL patients and 21 controls. We analyzed the methylation status of the target genes using methylation-specific PCR. We also examined whether the exosomes and the tumor samples contained transcripts of the target genes. KEY FINDINGS: We found that CDKN2A and CDKN2B were methylated in both plasma exosomes and primary tumor tissue samples. None of the transcripts were found in the exosomes except CDKN1B which was expressed in 8 (38%) of the exosome samples. SIGNIFICANCE: This study showed that plasma exosomes might preferably package certain target molecules from primary tumors and the exosomes containing dual methylated DNAs of CDKN2A and CDKN2B, or CDKN1B transcript may contribute to DLBCL pathogenesis.

EZH2 inhibitors reverse resistance to gefitinib in primary EGFR wild-type lung cancer cells.

BACKGROUND: Lung cancer is the leading cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. In traditional anti-cancer therapy, epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKI) have been proven to be beneficial for patients with EGFR mutations. However, patients with EGFR wild-type NSCLC were usually not respond to EGFR-TKIs. Enhancer of zeste homolog 2 (EZH2) is a key molecular in the PRC2 complex and plays an important role in epigenetic regulation and is overexpressed in variant tumors. EZH2 inhibitors have been reported to sensitize variant tumor cells to anticancer drugs. This study aimed to investigate whether the EZH2 inhibitors, GSK343 and DZNep when combined with gefitinib can reverse EGFR-TKIs resistance in EGFR wild-type NSCLC cells. METHODS: The RNA-sequencing data of patients with NSCLC [502 patients with lung squamous cell carcinoma, including 49 paracancerous lung tissues and 513 patients with lung adenocarcinoma (LUAD), including 59 paracancerous lung tissues] from the Cancer Genome Atlas (TCGA), were analyzed for EZH2 expression. EZH2 expression was verified in 40 NSCLC tissue cancer samples and their corresponding paracancerous tissues from our institute (TJMUGH) via RT-PCR. A549 and H1299 cells treated with siRNA or EZH2 inhibitors were subjected to cell viability and apoptosis analyses as well to EGFR pathway proteins expression analyses via western blotting. RESULTS: EZH2 was upregulated in human NSCLC tissues and correlated with poor prognosis in patients with LUAD based on data from both TCGA and TJMUGH. Both GSK343 and DZNep sensitized EGFR wild-type LUAD cells (A549 and H1299) to gefitinib and suppressed cell viability and proliferation in vitro by downregulating the phosphorylation of EGFR and AKT and by inducing cell apoptosis. Co-administration of EZH2 inhibitors (GSK343 or DZNep) with gefitinib exerted a stronger inhibitory effect on tumor activity, cell proliferation and cell migration than single drug administration in vitro and in vivo. CONCLUSIONS: These data suggest that the combination of EZH2 inhibitors with EGFR-TKIs may be an effective method for treating NSCLC-patients with EGFR-wild type, who do not want to undergo traditional treatment with chemotherapy.

Curcumin inhibits the growth of triple-negative breast cancer cells by silencing EZH2 and restoring DLC1 expression.

Enhancer of zeste homolog 2 (EZH2), an oncogene, is a commonly up-regulated epigenetic factor in human cancer. Hepatocellular carcinoma deletion gene 1 (DLC1) is an antioncogene that is either expressed at low levels or not expressed in many malignant tumours. Curcumin is a promising anticancer drug that has antitumour effects in many tumours, but its mechanism of action is unclear. Our research demonstrated that EZH2 was up-regulated in breast cancer (BC) tissues and cells, whereas DLC1 was down-regulated, and the expression of EZH2 and DLC1 was negatively correlated in BC. By analysing the characteristics of clinical cases, we found that positive expression of EZH2 and negative expression of DLC1 may be predictors of poor prognosis in patients with triple-negative breast cancer (TNBC). Moreover, knockdown of EZH2 expression restored the expression of DLC1 and inhibited the migration, invasion and proliferation, promoted the apoptosis, and blocked the cell cycle of MDA-MB-231 cells. Furthermore, we found that curcumin restored the expression of DLC1 by inhibiting EZH2; it also inhibited the migration, invasion and proliferation of MDA-MB-231 cells, promoted their apoptosis and blocked the cell cycle. Finally, xenograft tumour models were used to demonstrate that curcumin restored DLC1 expression by inhibiting EZH2 and also inhibited the growth and promoted the apoptosis of TNBC cells. In conclusion, our results suggest that curcumin can inhibit the migration, invasion and proliferation, promote the apoptosis, block the cycle of TNBC cells and restore the expression of DLC1 by inhibiting the expression of EZH2.

Altered expression of epigenetic modifiers EZH2, H3K27me3, and DNA methyltransferases in meningiomas - prognostic biomarkers for routine practice.

INTRODUCTION: Meningiomas comprises of a wide variety of histological entities with heterogeneous biological behaviour and prognosis. The plethora of genetic data are yet to produce relevant biomarkers for routine use. In contrast, epigenetic alterations are less elucidated. MATERIAL AND METHODS: The expression of the key molecules involved in the two principal epigenetic systems, i.e. DNA methylation (DNA methyltransferases [DNMT-1, -3A and -3B]) and histone modification (Enhancer of Zeste homolog-2 [EZH2] and trimethyl histone-3 [H3K27me3]) were assessed in 149 cases of meningiomas (grade I - 102, grade II - 47) by immunohistochemistry. RESULTS: Immunopositivity for EZH2 (38.3% vs. 6.0%) and negativity for H3K27me3 (10.6% vs. 1.0%) were significantly more common in grade II tumours. Both were associated with significantly higher proliferative activity. The majority of the cases of both grades showed expression of all three DNMTs. However, high expression of DNMT-1 was significantly more common in grade II tumours (87.8% vs. 66.2%). Expression of EZH2 and loss of H3K27me3 were associated with significantly shorter progression-free survival (hazard ratio [HR] = 4.07 and 0.24, respectively). CONCLUSIONS: The key epigenetic regulators play important roles in the pathobiology of meningiomas. EZH2 positivity and H3K27me3 negativity are associated with aggressive tumour-biology and poor prognosis. Both these markers can easily be assessed by immunohistochemistry and can be incorporated in routine practice.

Decreased miR-124 contributes to the epithelial-mesenchymal transition phenotype formation of lung adenocarcinoma cells via targeting enhancer of zeste homolog 2.

INTRODUCTION: MiR-124, a tumor suppressor, is involved in regulating various cellular processes. The purpose of this study was to investigate the possible function of miR-124 in LA (lung adenocarcinoma) cells. AIMS: MiR-124 expression levels in the 54 pairs of LA tissues (and corresponding non-tumor tissues) obtained at the Sixth People's Hospital of Yancheng City and in LA cells were assessed by qRT-PCR. Colony formation assay, wound healing assay, transwell assays, attachment/detachment, western blotting and immunofluorescence assays were performed to assess the function of miR-124 on proliferation, migration and epithelial-to-mesenchymal (EMT) phenotypes in LA cells in vitro. Enhancer of zeste homolog 2 (EZH2) is identified as a target of miR-124 by bioinformatics analysis and luciferase reporter assays. Rescue assays were applied to verify the relationship between miR-124 and EZH2. RESULTS: MiR-124 was down-regulated in LA tissues (compared to adjacent non-tumor tissues), and was down-regulated in 3 out of 4 lung cancer cell lines compared to immortalized, non-tumorigenic bronchial epithelial cells. Forced expression of miR-124 significantly suppressed tumor cell proliferation, migration and inhibited the EMT process. On the contrary, deletion of miR-124 could obviously promote cell proliferation, migration and facilitate the formation of EMT phenotype. Bioinformatics analysis and luciferase reporter assays confirmed that EZH2 was a target gene of miR-124 and was negatively correlated with the level of miR-124 in cancer tissues. CONCLUSION: Our current study suggested that miR-124 was a tumor suppressor in LA, and miR-124 was associated with LA cell EMT phenotype formation via targeting EZH2.

Epigenetic Regulation of KL (Klotho) via H3K27me3 (Histone 3 Lysine [K] 27 Trimethylation) in Renal Tubule Cells.

KL (klotho) levels decline with age, which is an important mechanistic driver of aging. KL gene deficiency is associated with hypertension. The purpose of this study is to investigate the potential role of H3K27me3 (histone 3 lysine [K] 27 trimethylation) in the regulation of KL gene expression and examine the related molecular pathways that may drive kidney cell aging. Kidneys were collected from 6-month-old WT (wild type; young WT), 30-month-old WT (aged WT), and 6- (young) and 20-month-old (aged) KL mutant mice, respectively. We demonstrated that the H3K27me3 level was increased in kidneys of aged WT and KL mutant mice versus young WT mice. Elevation of H3K27me3 levels was likely due to downregulation of the H3K27 (histone H3 Lys 27)-specific demethylase JMJD3 (the Jumonji domain containing-3) in the aged kidneys. Inhibition of PRC2 (polycomb repressive complex C2; histone trimethyltransferase) decreased the H3K27me3 levels leading to an increase in the expression of KL in cultured primary renal tubule cells assessed by Western blot and KL promoter activity assays. The chromatin immunoprecipitation qPCR assay revealed that H3K27me3 was physically associated with the KL promoter region. Furthermore, aging impaired the SGK1 (serum- and glucocorticoid-induced protein kinase 1)/FOXO3a (the forkhead box class O 3a) signaling leading to upregulation of p53 and p16 (aging markers) in the kidney of aged WT mice. KL may regulate the SGK1/FOXO3 signaling, which was decreased due to KL deficiency. Thus, aging-associated downregulation of KL gene expression may be partly attributed to upregulation of H3K27me3 levels. Downregulation of KL may impair the SGK1/FOXO3 signaling contributing to kidney cell aging.

MicroRNA-625-3p inhibits gastric cancer metastasis through modulating EZH2.

OBJECTIVE: The aim of this study was to investigate whether microRNA-625-3p participated in the malignant progression of gastric cancer and inhibited GCa metastasis by regulating EZH2 (Enhancer of zeste homolog 2). PATIENTS AND METHODS: Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was performed to examine the expression of microRNA-625-3p in 36 pairs of GCa tissues and para-cancerous tissues. The interplay between microRNA-625-3p level and clinical indexes or prognosis of GCa patients was analyzed. MicroRNA-625-3p mimics and inhibitors, as well as their negative controls, were transfected into GCa cell lines to establish microRNA-625-3p overexpression and down-regulation models in vitro, respectively. QRT-PCR was applied to further verify the transfection efficiency. Cell counting kit-8 (CCK-8), colony formation, and transwell assays were performed to analyze the impact of microRNA-625-3p on the proliferative and invasiveness abilities of GCa AGS and SGC-7901 cells. Finally, the regulatory mechanism of microRNA-625-3p on the downstream gene EZH2 was explored by cell reverse experiment. RESULTS: QRT-PCR results revealed that microRNA-625-3p expression level in GCa tissues was remarkably lower than that of adjacent tissues, and the difference was statistically significant (p<0.05). Compared with patients with high expression of microRNA-625-3p, the incidence of lymph node or distant metastasis was significantly higher in patients with low expression of miR-625-3p, whereas the overall survival rate was lower (p<0.05). Compared with GCa cells in NC inhibitor group, the proliferative ability and invasiveness of cells in microRNA-625-3p inhibitor group were remarkably promoted (p<0.05). However, the opposite results were observed in microRNA-625-3p mimics group. Our findings further demonstrated that the expression of EZH2 increased remarkably in GCa cell lines and tissues (p<0.05). Meanwhile, its expression level was negatively correlated with microRNA-625-3p level. Cell reverse experiment showed that EZH2 could offset the influence of microRNA-625-3p on the proliferation and metastasis GCa cells, thereby affecting the malignant progression of GCa. CONCLUSIONS: MicroRNA-625-3p was remarkably correlated with lymph node or distant metastasis and poor prognosis of GCa patients. In addition, microRNA-625-3p might inhibit the malignant progression of GCa via modulating EZH2.

Knockdown of CTCF reduces the binding of EZH2 and affects the methylation of the SOCS3 promoter in hepatocellular carcinoma.

The epigenetic silencing mechanism of suppressor 3 of cytokine signaling (SOCS3) in cancers has not been fully elucidated. Polycomb repressive complexes 2 (PRC2), an important epigenetic regulatory factors, exerts a critical role in repressing the initial phase of gene transcription. Whether PRC2 participates the down- regulation of SOCS3 in Hepatocellular carcinoma (HCC) remains unclear and how does PRC2 be recruited target gene still needs to explore. In this study, Using TCGA HCC dataset, and detecting HCC tissue specimens and cell lines, we found that SOCS3 expression in HCC was inversely related to that of EZH2, and depended on its promoter methylation status. CTCF, vigilin, EZH2 and H3K27me3 were enriched at CTCF and EZH2 binding sites on the methylated SOCS3 gene promoter. The depletion of CTCF did not affect expression of EZH2 and DNMT1, but decrease recruitment of CTCF, vigilin, EZH2 and H3K27me3. Further, knockdown of CTCF led to a loss of methylation of the methylated SOCS3 promoter, which sequentially increased the expression of SOCS3 and decreased the expression of pSTAT3, the downstream effector. These findings suggest that the CTCF dependent recruitment of EZH2 to the SOCS3 gene promoter is likely to participate in the epigenetic silencing of SOCS3 and in regulating its gene expression.

RUNX1 mutation in a patient with myelodysplastic syndrome and decreased erythrocyte expression of blood group A antigen.

BACKGROUND: Loss of blood group ABO antigens on red blood cells (RBCs) is well known in patients with leukemias, and such decreased ABO expression has been reported to be strongly associated with hypermethylation of the ABO promoter. We investigated the underlying mechanism responsible for A-antigen reduction on RBCs in a patient with myelodysplastic syndrome. STUDY DESIGN AND METHODS: Genetic analysis of ABO was performed by PCR and sequencing using peripheral blood. RT-PCR were carried out using cDNA prepared from total bone marrow (BM) cells. Bisulfite genomic sequencing was performed using genomic DNA from BM cells. Screening of somatic mutations was carried out using a targeted sequencing panel with genomic DNA from BM cells, followed by transient transfection assays. RESULTS: Genetic analysis of ABO did not reveal any mutation in coding regions, splice sites, or regulatory regions. RT-PCR demonstrated reduction of A-transcripts when the patient's RBCs were not agglutinated by anti-A antibody and did not indicate any significant increase of alternative splicing products in the patient relative to the control. DNA methylation of the ABO promoter was not obvious in erythroid cells. Targeted sequencing identified somatic mutations in ASXL1, EZH2, RUNX1, and WT1. Experiments involving transient transfection into K562 cells showed that the expression of ABO was decreased by expression of the mutated RUNX1. CONCLUSION: Because the RUNX1 mutation encoded an abnormally elongated protein without a transactivation domain which could act as dominant negative inhibitor, this frame-shift mutation in RUNX1 may be a genetic candidate contributing to A-antigen loss on RBCs.

Overexpression of enhance of Zeste homolog 2 (EZH2) in endometrial carcinoma: An NRG Oncology/Gynecologic Oncology Group Study.

OBJECTIVES: Enhancer of zeste homolog 2 (EZH2) is a histone methyl transferase that mediates epigenetic silencing of tumor suppressor genes. It is commonly over-expressed in several solid tumors and has been shown to be a prognostic biomarker. We investigated patterns of EZH2 expression in endometrial cancer. METHODS: Evaluation of EZH2 expression was completed on both early and advanced stage endometrioid adenocarcinoma tissues and a subset of matched normal mullerian tissue samples, from participants enrolled in Gynecologic Oncology Group (GOG) protocol 210, using real time reverse transcription polymerase chain reaction (RT-PCR) and western blot (WB) analysis. Non-parametric methods were used to assess differences in mRNA and protein expression respectively with known clinical/pathologic prognostic factors. Survival analysis was performed using techniques including Cox proportional hazards (PH) model to evaluate differences in progression free survival (PFS) and overall survival (OS) based on EZH2 expression. RESULTS: Eighty-seven patient samples were analyzed that included 60 tumors and 27 matched-normal tissue specimens. EZH2 mRNA (p < .0001) and protein expression (p < .0001) in tumor specimens were significantly higher than in matched-normal tissue. In primary tumors, EZH2 protein expression was associated with lympho-vascular space invasion (LVSI, p = .044), and EZH2 mRNA expression was associated with age (p = .037). Differences in EZH2 expression between primary tumors and matched normal tissue were not associated with other known clinical and pathologic factors. However, there did appear to be a trend toward decreased progression-free survival among patients with high EZH2 expression levels. CONCLUSIONS: Our results confirm the differential expression of EZH2 in uterine cancers compared to normal tissues. However, there were no statistically significant differences in survival associated with EZH2 expression in patients with endometrial cancer. NCT #: NCT00340808.