Increased EZH2 Expression is Associated With Proliferation and Progression of Cervical Cancer and Indicates a Poor Prognosis:

Treating human cancer by targeting EZH2

Enhancer of zeste homolog 2 (EZH2), an epigenetic regulator that primarily inhibits downstream gene expression by tri-methylating histone H3, which is usually overexpressed in tumors and participates in many processes such as tumor occurrence and development, invasion, migration, drug resistance, and anti-tumor immunity as an oncogene, making it an important biomarker in cancer therapy. Collectively, several transcription factors and RNAs cooperate to facilitate the elevated expression of EZH2 in cancer. Although the significance of blocking EZH2 in cancer for inhibiting cancer progression is widely recognized, the clinical application of EZH2 inhibitors continues to encounter numerous challenges. In this review, drawing upon our comprehensive understanding of the factual underpinnings of EZH2's role in cancer, we aim to clarify the crucial importance of targeting EZH2 in cancer treatment. Furthermore, we summarize the current research landscape surrounding targeted EZH2 inhibitors and offer insights into potential future applications of these inhibitors.

Identification of N6-methyladenosine-associated ferroptosis biomarkers in cervical cancer

BACKGROUND

Cervical cancer (CC) stands as a major contributor to female mortality. The pathogenesis of CC is linked with various factors. Our research aimed to unravel the underlying mechanisms of ferroptosis and m6A RNA methylation in CC through bioinformatics analysis.

METHODS

Three CC datasets, including GSE9750, GSE63514, and TCGA-CESC, were incorporated. m6A-related genes were derived from published sources, while ferroptosis-related genes were obtained from the FerrDb database. Differential expression and correlation analyses were performed to identify differentially expressed m6A-related ferroptosis genes (DE-MRFGs) in CC. Subsequently, the biomarkers were further identified using machine learning techniques. Gene Set Enrichment Analysis (GSEA) and Kaplan-Meier (KM) survival analysis were also performed to comprehend these biomarkers. Furthermore, a competing endogenous RNAs (ceRNA) network involving biomarkers was established. Finally, biomarkers expression were verified by real-time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

From the DE-MRFGs, six genes, including ALOX12, EZH2, CA9, CDCA3, CDC25A, HSPB1, were selected. A nomogram constructed based on these biomarkers exhibited potential clinical diagnostic value for CC, with good diagnostic accuracy confirmed through calibration curves. GSEA unveiled associations of these biomarkers with cell proliferation, spliceosome, and base excision repair. KM survival analysis demonstrated significant differences in survival outcomes between high and low expressions of HSPB1, EZH2, and CA9 samples. A ceRNA network was constructed involving three biomarkers, such as CDC25A, CDCA3, and EZH2, 29 miRNAs, and 25 lncRNAs. In RT-qPCR verification, the expression of ALOX12, EZH2 and CDC25A was significantly higher in CC samples, while HSPB1 expression was higher in control samples.

CONCLUSION

Six genes, namely ALOX12, EZH2, CA9, CDCA3, CDC25A, and HSPB1, were identified as m6A-regulated ferroptosis biomarkers in CC. These findings offer valuable insights into disease pathogenesis and hold promise for advancing CC treatment and prognosis.

ARMH1 is a novel marker associated with poor pediatric AML outcomes that affect the fatty acid synthesis and cell cycle pathways

Introduction

Despite remarkable progress in Pediatric Acute Myeloid Leukemia (pAML) treatments, the relapsed disease remains difficult to treat, making it pertinent to identify novel biomarkers of prognostic/therapeutic significance.

Material and methods

Bone marrow samples from 21 pAML patients were analyzed using single cell RNA sequencing, functional assays with ARMH1 knockdown and overexpression were performed in leukemia cell lines to evaluate impact on proliferation and migration, and chemotherapy sensitivity. Mitochondrial function was assessed via Seahorse assay, ARMH1 interacting proteins were studied using co-immunoprecipitation. Bulk RNA-seq was performed on ARMH1knockdown and over expressing cell lines to evaluate the pathways and networks impacted by ARMH1.

Results

Our data shows that ARMH1, a novel cancer-associated gene, is highly expressed in the malignant blast cells of multiple pediatric hematologic malignancies, including AML, T/B-ALL, and T/B-MPAL. Notably, ARMH1 expression is significantly elevated in blast cells of patients who relapsed or have a high-risk cytogenetic profile (MLL) compared to standard-risk (RUNX1, inv (16)). ARMH1 expression is also significantly correlated with the pediatric leukemia stem cell score of 6 genes (LSC6) associated with poor outcomes. Perturbation of ARMH1 (knockdown and overexpression) in leukemia cell lines significantly impacted cell proliferation and migration. The RNA-sequencing analysis on multiple ARMH1 knockdown and overexpressing cell lines established an association with mitochondrial fatty acid synthesis and cell cycle pathways.The investigation of the mitochondrial matrix shows that pharmacological inhibition of a key enzyme in fatty acid synthesis regulation, CPT1A, resulted in ARMH1 downregulation. ARMH1 knockdown also led to a significant reduction in CPT1A and ATP production as well as Oxygen Consumption Rate. Our data indicates that downregulating ARMH1 impacts cell proliferation by reducing key cell cycle regulators such as CDCA7 and EZH2. Further, we also established that ARMH1 is a key physical interactant of EZH2, associated with multiple cancers.

Conclusion

Our findings underscore further evaluation of ARMH1 as a potential candidate for targeted therapies and stratification of aggressive pAML to improve outcomes.

EZH2-mediated development of therapeutic resistance in cancer

Enhancer of zeste homolog 2 (EZH2) regulates gene expression and plays a definite role in cell proliferation, apoptosis, and senescence. Overexpression of EZH2 has been found in various human malignancies, including prostate, breast, and ovarian cancers, and is associated with increased metastasis and poor prognosis. EZH2 catalyzes trimethylation of lysine 27 of histone H3 (H3K27me3) as a canonical role in a PRC2-dependent manner. This mechanism silences various tumor suppressor genes through EZH2-mediated histone lysine methyltransferase activity. As a non-canonical role, EZH2 partners with other signaling molecules to undergo post-translational modification to orchestrate its function as a co-activator playing a critical role in cancer progression. Dysregulation of EZH2 has also been associated with therapeutic resistance in cancer cells. Given the role of EZH2 in promoting carcinogenesis and therapy resistance, both canonical and non-canonical EZH2 inhibitors have been used to combat multiple cancer types. Moreover, combining EZH2 inhibitors with other therapeutic modalities have shown to enhance the therapeutic efficacy and overcome potential resistance mechanisms in these cancerous cells. Therefore, targeting EZH2 through canonical and non-canonical modes appears to be a promising therapeutic strategy to enhance efficacy and overcome resistance in multiple cancers.

Evaluation of Immunohistochemical Expression of Enhancer of Zeste Homolog 2 (EZH2) and Its Association With Clinicopathological Variables in Carcinoma Cervix

INTRODUCTION

 Carcinoma cervix is the fourth most common cancer worldwide and is one of the leading causes of cancer death in women. Recently, immunohistochemical expression of biomarkers has been utilized as indicators of disease progression, aggressiveness for predicting the prognosis in various cancers. DNA methylation of genes plays an important role in pathogenesis of carcinoma cervix and detection of aberrant methylation can be utilized for detection of carcinoma cervix and monitoring of its progression. Enhancer of Zeste Homolog 2 (EZH2) is a histone methyltransferase and catalyzes methylation of histone H3 and plays an important role in tumor cell proliferation, invasion, and metastasis. The aim of this study was to analyze the pattern, distribution, and grade of immunohistochemical expression of EZH2 in carcinoma cervix and study its association with clinico-pathological variables such as age, site and size of tumor, type of growth, tumor grade, histological subtype, lymph node metastasis, and stage of the tumor according to the Federation of Gynaecology and Obstetrics (FIGO).

MATERIALS AND METHODS

 This observational study was carried out in the Department of Pathology & Lab Medicine, at our institute. A total of 60 consecutive histopathologically confirmed cases of carcinoma cervix from January 2018 to June 2022 were subjected to immunohistochemistry (IHC) for EZH2. The immunohistochemical score for each case was obtained by multiplying the intensity and percentage of positive cells for EZH2. An immunohistochemical score of four or greater than four was considered as high immunoexpression. The immunohistochemical results were correlated with clinico-pathological variables.

RESULTS

 The data were analyzed using relevant statistical methods using SPSS version 23 (IBM Corp., Armonk, NY). To find the significant difference (p value) and association, chi-square test along with Pearson chi-square were used, wherever necessary. A p value of <0.05 was considered as significant. High immunoexpreesion of EZH2 exhibited a significant association (p < 0.05) with the tumor grade, histologic subtype, lymphnode metastasis, and FIGO stage.

CONCLUSIONS

 The results of our study affirm that a significant association exists between immunohistochemical expression of EZH2 with tumor grade, histological subtype, lymphnode metastasis, and FIGO stage which can be utilized in future studies with larger sample size to further strengthen the association of EZH2 immunoexpression in cancer cervix patients that may aid in the development of the targeted therapy in near future.

An integrative approach toward identification and analysis of therapeutic targets involved in HPV pathogenesis with a focus on carcinomas

BACKGROUND

Persistent infection of high-risk HPVs is known to cause diverse carcinomas, mainly cervical, oropharyngeal, penile, etc. However, efficient treatment is still lacking.

OBJECTIVE

Identify and analyze potential therapeutic targets involved in HPV oncogenesis and repurposing drug candidates.

METHODS

Integrative analyses were performed on the compendium of 1887 HPV infection-associated or integration-driven disrupted genes cataloged from the Open Targets Platform and HPVbase resource. Potential target genes are prioritized using STRING, Cytoscape, cytoHubba, and MCODE. Gene ontology and KEGG pathway enrichment analysis are performed. Further, TCGA cancer genomic data of CESC and HNSCC is analyzed. Moreover, regulatory networks are also deduced by employing NetworkAnalyst.

RESULTS

We have implemented a unique approach for identifying and prioritizing druggable targets and repurposing drug candidates against HPV oncogenesis. Overall, hundred key genes with 44 core targets were prioritized with transcription factors (TFs) and microRNAs (miRNAs) regulators pertinent to HPV pathogenesis. Genomic alteration profiling further substantiated our findings. Among identified druggable targets, TP53, NOTCH1, PIK3CA, EP300, CREBBP, EGFR, ERBB2, PTEN, and FN1 are frequently mutated in CESC and HNSCC. Furthermore, PIK3CA, CCND1, RFC4, KAT5, MYC, PTK2, EGFR, and ERBB2 show significant copy number gain, and FN1, CHEK1, CUL1, EZH2, NRAS, and H2AFX was marked for the substantial copy number loss in both carcinomas. Likewise, under-explored relevant regulators, i.e., TFs (HINFP, ARID3A, NFATC2, NKX3-2, EN1) and miRNAs (has-mir-98-5p, has-mir-24-3p, has-mir-192-5p, has-mir-519d-3p) is also identified.

CONCLUSIONS

We have identified potential therapeutic targets, transcriptional and post-transcriptional regulators to explicate HPV pathogenesis as well as potential repurposing drug candidates. This study would aid in biomarker and drug discovery against HPV-mediated carcinoma.

Epigenetic Regulation by Polycomb Complexes from Drosophila to Human and Its Relation to Communicable Disease Pathogenesis

Although all cells in the human body are made of the same DNA, these cells undergo differentiation and behave differently during development, through integration of external and internal stimuli via 'specific mechanisms.' Epigenetics is one such mechanism that comprises DNA/RNA, histone modifications, and non-coding RNAs that regulate transcription without changing the genetic code. The discovery of the first Polycomb mutant phenotype in Drosophila started the study of epigenetics more than 80 years ago. Since then, a considerable number of Polycomb Group (PcG) genes in Drosophila have been discovered to be preserved in mammals, including humans. PcG proteins exert their influence through gene repression by acting in complexes, modifying histones, and compacting the chromatin within the nucleus. In this article, we discuss how our knowledge of the PcG repression mechanism in Drosophila translates to human communicable disease research.

The role of UXT in tumors and prospects for its application in hepatocellular carcinoma

UXT is widely expressed in human and mouse tissues and aberrantly expressed in various tumor tissues. UXT may play a pro-cancer or tumor suppressor role in different tumor types and microenvironments with different mechanisms of action. Studies have shown that UXT can interact with related receptors to exert its functions and affect tumor proliferation and metastasis, leading to a poor prognosis when the biological functions of these tumors are changed. Interestingly, the signaling pathways and mechanism-related molecules that interact with UXT are closely related to the occurrence of hepatocellular carcinoma (HCC) during disease progression. This article reviews the research progress of UXT and prospects for its application in HCC, with the aim of providing possible scientific suggestions for the basic research, diagnosis and treatment of HCC.

Ultrasound microbubble-mediated delivery of ANLN silencing-repressed EZH2 expression alleviates cervical cancer progression

Ultrasound-targeted microbubble destruction (UTMD) is a new gene therapy method that uses ultrasound and microbubbles carrying target genes to achieve gene transfection. However, whether UTMD-mediated ANLN silencing transfection helps to restrain the growth of cervical cancer (CC) is obscure. ANLN level in tumor tissues, adjacent tissues, and cells was tested using the database, qRT-PCR, and western blot. The optimal concentration of SF6 was determined by MTT assay. Mechanical index (MI) was selected by flow cytometry. After transfection with liposome or UTMD-mediated liposome, cell function experiments, qRT-PCR, and western blot were employed to assess CC cell biological behaviors and EZH2 level. Epithelial-mesenchymal transition (EMT)-related marker and apoptosis-related marker expressions were examined utilizing qRT-PCR and western blot. 10% SF6 and MI of 0.28 were selected for subsequent tests. ANLN was highly expressed in CC and cells. The transfection efficiency of the UTMD-siANLN group was higher than that of the L-siANLN group. Moreover, the repression of UTMD-siANLN on CC cell malignant phenotypes was stronger than L-siANLN. UTMD-siANLN attenuated EZH2 expression in CC cells. The modulatory role of UTMD-siANLN on EMT- and apoptosis-related markers was reversed by EZH2 overexpression. UTMD can improve the efficiency of siANLN transfection into CC cells to induce suppression of CC cell malignant phenotypes, which may become a new target of gene therapy for CC.

EZH2 affects malignant progression and DNA damage repair of lung adenocarcinoma cells by regulating RAI2 expression

BACKGROUND

Lung adenocarcinoma (LUAD) is featured in high morbidity and mortality. Aberrant activation of the histone methyltransferase EZH2 has close association with cancer progression. This research aimed to deeply dive into the role and possible molecular mechanisms of EZH2 and its downstream genes in malignant progression and DNA damage repair of LUAD cells.

METHODS

Expression of EZH2 in LUAD cells was analyzed by qRT-PCR, and the effects of EZH2 on proliferation, and apoptosis of LUAD cells were examined by CCK-8, colony formation and flow cytometry assays. The downstream targets of EZH2 were predicted by bioinformatics analysis. Then, the targeting relationship between EZH2 and RAI2 was examined by CHIP and luciferase reporter assays. Rescue assay were used to further validate the effect of EZH2/RAI2 on the malignant progression of LUAD cells. The expression levels of EZH2, RAI2 and p53 were examined by Western blot.

RESULTS

Upregulation of EZH2 was identified in LUAD tissues and cells. RAI2 was a downstream target gene of EZH2, and the two were negatively correlated. Silencing EZH2 suppressed proliferation of LUAD cells, promoted expression of p53, cell cycle arrest and apoptosis. While silencing RAI2 could reverse the above-mentioned effects caused by EZH2 silencing.

CONCLUSION

These results demonstrated that EZH2 promoted malignant progression and DNA damage repair of LUAD cells by targeting and negatively regulating RAI2.

Non-coding RNAs-EZH2 regulatory mechanisms in cervical cancer: The current state of knowledge

Cervical cancer (CC) is among the leading causes of death in women worldwide. Both genetic and epigenetic regulators are required for the tumorigenesis and progression of CC. Non-coding RNAs (ncRNAs) are a group of RNAs that don't code for proteins yet constitute a large part of the human transcriptome, including long non-coding RNAs (lncRNAs), microRNAs (miRNAs), circular RNAs (circRNA), and other forms of non-coding RNAs. Deregulation of lncRNA, miRNA, and circRNA is implicated in the oncogenesis and development of cervical malignancies, acting as oncogenic drivers or tumor suppressors. Enhancer of zeste homolog 2 (EZH2) is the enzymatic subunit of Polycomb Repressive Complex 2 (PRC2), which functions to methylate histone H3 lysine 27 to silence gene transcription. Converging lines of evidence have revealed the oncogenic role played by EZH2 in cancers. EZH2 is upregulated in CC tissues with a robust correlation to the advanced stage, metastasis, and poor survival rate in patients. The elucidation of the roles of EZH2 in cancer has driven the development of therapeutic EZH2 inhibitors, which are approaching phase I or phase I/II clinical trials. Here we review the ncRNA-EZH2 regulatory pathways in CC that unify EZH2 and ncRNAs as an integrated system in the development of CC. Given the emerging findings for the role of the ncRNA-EZH2 regulatory axis in CC, it will be of great interest to develop novel therapeutic strategies based on their relationship.

Identification of Cross-Pathway Connections via Protein-Protein Interactions Linked to Altered States of Metabolic Enzymes in Cervical Cancer

Metabolic reprogramming is one of the emerging hallmarks of cancer cells. Various factors, such as signaling proteins (S), miRNA, and transcription factors (TFs), may play important roles in altering the metabolic status in cancer cells by interacting with metabolic enzymes either directly or via protein-protein interactions (PPIs). Therefore, it is important to understand the coordination among these cellular pathways, which may provide better insight into the molecular mechanism behind metabolic adaptations in cancer cells. In this study, we have designed a cervical cancer-specific supra-interaction network where signaling pathway proteins, TFs, and microRNAs (miRs) are connected to metabolic enzymes via PPIs to investigate novel molecular targets and connections/links/paths regulating the metabolic enzymes. Using publicly available omics data and PPIs, we have developed a Hidden Markov Model (HMM)-based mathematical model yielding 94, 236, and 27 probable links/paths connecting signaling pathway proteins, TFs, and miRNAs to metabolic enzymes, respectively, out of which 83 paths connect to six common metabolic enzymes (RRM2, NDUFA11, ENO2, EZH2, AKR1C2, and TYMS). Signaling proteins (e.g., PPARD, BAD, GNB5, CHECK1, PAK2, PLK1, BRCA1, MAML3, and SPP1), TFs (e.g., KAT2B, ING1, MED1, ZEB1, AR, NCOA2, EGR1, TWIST1, E2F1, ID4, RBL1, ESR1, and HSF2), and miR (e.g., mir-147a, mir-593-5p, mir-138-5p, mir-16-5p, and mir-15b-5p) were found to regulate two key metabolic enzymes, EZH2 and AKR1C2, with altered metabolites (L-lysine and tetrahydrodeoxycorticosterone, THDOC) status in cervical cancer. We believe, the biology-based approach of our system will pave the way for future studies, which could be aimed toward identifying novel signaling, transcriptional, and post-transcriptional regulators of metabolic alterations in cervical cancer.

The significance of enhancer of zeste homolog 2 (EZH2) expression in spindle cell lesions of the breast

Spindle cell lesions of the breast are rare entities and pose a diagnostic challenge for pathologists due to overlapping morphologic and immunohistochemical features. We evaluated EZH2 expression in various benign (fibromatosis (n = 8), myofibroblastoma (n = 7), neurofibroma (n = 1), nodular fasciitis (n = 5), benign phyllodes tumor (n = 18)) and malignant (malignant phyllodes tumor (n = 8), metaplastic breast carcinoma (n = 16) and angiosarcoma (n = 8)) spindle cell lesions as a potential diagnostic and therapeutic marker. The EZH2 expression was evaluated semi-quantitatively to categorize the cases as 'low' and 'high' expression. All benign lesions showed low EZH2 expression, whereas high EZH2 expression was observed in the majority (28/32; 88%) of malignant lesions. The study results suggest that EZH2 may be used both as an additional diagnostic tool to reach an accurate diagnosis of the spindle cell lesions of the breast and as a therapeutic target for the malignant lesions.

Clinical impact of EZH2 and its antagonist SMARCA4 in ovarian cancer

SMARCA4 and EZH2 are two functional key players of their respective antagonizing chromatin remodeling complexes SWI/SNF and PRC2. EZH2 inhibitory drugs may abrogate pro-oncogenic features of PRC2 and turn the balance to cell differentiation via SWI/SNF activity in cancers. SMARCA4 and EZH2 expression was assessed by RT-PCR in 238 epithelial ovarian cancers (OCs) and put in relation to clinico-pathological parameters and patients' outcome. Optimal thresholds for high and low expression of both variables were calculated by the Youden's index based on receiver operating characteristic (ROC) curves. High SMARCA4 mRNA expression was independently associated with favorable progression-free survival (PFS) (P = 0.03) and overall survival (OS) (P = 0.018). As Youden's threshold determination for EZH2 yielded a S-shaped ROC-curve, two cut-off points (29th and 94th percentile) predicting opposite features were defined. Whereas EZH2 mRNA levels beyond the 29th percentile independently predicted poor PFS (P = 0.034), Cox-regression in EZH2 transcripts above the 94th percentile revealed a conversion from unfavorable to favorable PFS and OS (P = 0.009 and P = 0.032, respectively). High SMARCA4 expression associates with improved survival, whereas moderate/high EZH2 expression predicts poor outcome, which converts to favorable survival in ultra-high expressing OCs. This small OC subgroup could be characterized by REV7-abrogated platinum hypersensitivity but concomitant PARP-inhibitor resistance.

Identification of Core Prognosis-Related Candidate Genes in Cervical Cancer via Integrated Bioinformatical Analysis

Purposes

Cervical cancer (CC) is one of the highest frequently occurred malignant gynecological tumors with high rates of morbidity and mortality. Here, we aimed to identify significant genes associated with poor outcome. Materials and methods. Differentially expressed genes (DEGs) between CC tissues and normal cervical tissues were picked out by GEO2R tool and Venn diagram software. Database for Annotation, Visualization and Integrated Discovery (DAVID) was performed to analyze gene ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway. The protein-protein interactions (PPIs) of these DEGs were visualized by Cytoscape with Search Tool for the Retrieval of Interacting Genes (STRING). Afterwards, Kaplan-Meier analysis was applied to analyze the overall survival among these genes. The Gene Expression Profiling Interactive Analysis (GEPIA) was applied for further validation of the expression level of these genes.

Results

The mRNA expression profile datasets of GSE63514, GSE27678, and GSE6791 were downloaded from the Gene Expression Omnibus database (GEO). In total, 76 CC tissues and 35 normal tissues were collected in the three profile datasets. There were totally 73 consistently expressed genes in the three datasets, including 65 up-regulated genes and 8 down-regulated genes. Of PPI network analyzed by Molecular Complex Detection (MCODE) plug-in, all 65 up-regulated genes and 4 down-regulated genes were selected. The results of the Kaplan-Meier survival analysis showed that 3 of the 65 up-regulated genes had a significantly worse prognosis, while 3 of the 4 down-regulated genes had a significantly better outcome. For validation in GEPIA, 4 of 6 genes (PLOD2, ANLN, AURKA, and AR) were confirmed to be significantly deregulated in CC tissues compared to normal tissues.

Conclusion

We have identified three up-regulated (PLOD2, ANLN, and AURKA) and a down-regulated DEGs (AR) with poor prognosis in CC on the basis of integrated bioinformatical methods, which could be regarded as potential therapeutic targets for CC patients.

Carcinogenic roles and therapeutic effects of EZH2 in gynecological cancers

Enhancer of Zeste Homolog 2 (EZH2) is highly expressed in kinds of malignant tumors and related to tumor occurrence, development, and prognosis. EZH2 is the catalytic subunit of the polycomb repressive complex 2 (PRC2), which promotes cell proliferation, migration, and invasion by epigenetic regulation of anti-tumor gene. It can activate numerous tumor-associated signaling pathways and interfere with DNA damage repair. In recent years, large amounts of studies have shown that EZH2 is closely related to gynecologic-related malignancies and can be used as a potential target gene for the treatment of gynecological-related malignancies. This review summarizes the oncogenic function of EZH2 and introduces the recent advances in the development of EZH2 inhibitors. On this basis, future research prospect of EZH2 is proposed.

Epigenetic modulation enhances immunotherapy for hepatocellular carcinoma

BACKGROUND

Anti-PDL-1 immunotherapy for Hepatocellular Carcinoma (HCC) demonstrated a mixed response. Polycomb Repressor Complex 2(PRC2) contributes to the initiation and progression of HCC by suppressing tumor antigens and inhibiting an immune response. Two components of epigenetic modulation are Enhancer of Zeste Homolog 2 (EZH2, the catalytic component of PRC2) and DNA Methyltransferase 1 (DNMT1). We aim to investigate the potential role of epigenetic therapy targeting EZH2 and DNMT1 as a novel strategy to modulate immunotherapy response in HCC.

METHODS

HepG2, Hep3B, and Hepa1-6 HCC cell lines were treated with EZH2 inhibitor (DZNep) and DNMT1 inhibitor (5-Azacytidine) with and without anti-PDL-1. Quantitative RT-PCR and immunohistochemistry were performed to evaluate the expression of tumor suppressors, tumor antigens, and Th1 chemokines. In-vivo C57/LJ immunocompetent mice model with subcutaneous tumor inoculation was performed with intraperitoneal drug injections.

RESULTS

There was a significant upregulation of Th1 chemokines in HepG2 (CXCL9 5.5 ± 0.2 relative fold change; CXCL10 1.44 × 103 ± 37 relative fold change) and Hep3B (CXCL 9 6.85 × 103 ± 1.3 × 103 relative fold change; CXCL 10 2.15 × 103 ± 3.1 × 102 relative fold change). Additionally, there was a significant induction of cancer testis antigens NY-ESO-1 (3.6-3.7 ± 0.3 relative fold change) and LAGE (8.3-11.7 ± 1.9 relative fold change). In vivo model demonstrated statistically significant tumor regression in the combination treatment group (0.02 g ± 0.02) compared to epigenetic therapy (0.63 g ± 0.61) or immunotherapy alone (0.15 g ± 0.21) with untreated control (2.4 g ± 0.71). There was significantly increased trafficking of cytotoxic T- lymphocytes and associated apoptosis for the combination treatment group compared to epigenetic or immunotherapy alone.

CONCLUSIONS

This study demonstrates that epigenetic modulation could be a novel potential strategy to augment immunotherapy for HCC by stimulating T cell trafficking into tumor microenvironment via activation of transcriptionally repressed chemokine genes responsible for T-cell trafficking, inducing previously silent neoantigens for immune targets, and allowing tumor regression as a result. A clinical trial of this feasible combination therapy of these clinically available agents is warranted.

Correlation between EZH2 and CEP55 and lung adenocarcinoma prognosis

OBJECTIVE

Recently, accumulated evidence indicates that the enhancer of zeste homologue 2 (EZH2) is highly expressed in a wide range of cancer types, including NSCLC. The downstream genes regulated by EZH2 were screened using bioinformatics analysis. This study aimed to analyse the correlation between the downstream genes of EZH2 and the prognosis of lung adenocarcinoma.

METHODS

Expression and methylation data of lung adenocarcinoma were downloaded from The Cancer Genome Atlas (TCGA) (https://cancergenome.nih.gov/) database, and data were categorized into EZH2 overexpression and EZH2 downregulation groups according to EZH2 expression. The genes that showed opposite trends of methylation and expression changes were screened, and the association of gene expression was calculated. Based on the String database, a protein association analysis was conducted to identify genes related to EZH2, which are referred to as EZH2 regulation candidate genes. According to gene expression (GSE27262) and methylation (GSE66836) chip data in the Gene Expression Omnibus (GEO) (https://www.ncbi.nlm.nih.gov/geo/) database, the genes with differential expression and methylation in lung adenocarcinoma tissues were analysed, and the trends of EZH2 regulation candidate gene expression and methylation were verified to identify the EZH2 regulation candidate genes. Subsequently, MethHC (http://methhc.mbc.nctu.edu.tw/php/index.php) and UALCAN (http://ualcan.path.uab.edu/index.html) were employed to verify changes in the expression and methylation of EZH2 downstream regulation candidate genes and to analyse the correlation between these genes and the prognosis of lung adenocarcinoma.

RESULTS

Expression and methylation data of lung adenocarcinoma were downloaded from TCGA database and categorized into EZH2 overexpression and EZH2 downregulation groups according to EZH2 expression. A total of 337 genes that showed opposite trends of methylation and expression changes were obtained. The protein association analysis using the String (https://string-db.org/) database showed that 61 genes interact with EZH2 and 61 genes represent EZH2 downstream regulation candidate genes. Moreover, 222 genes obtained from GSE27262 and GSE66836 chip data were negatively correlated with methylation and expression changes, and centrosomal protein 55 (CEP55) was identified as the EZH2 downstream regulation candidate gene. CEP55 was upregulated in lung adenocarcinoma tissues and showed low methylation. According to gene expression data from TCGA database, CEP55 and EZH2 exhibit higher levels in lung adenocarcinoma tissue than in adjacent normal tissue. Finally, the survival analysis revealed that EZH2 is not associated with the prognosis of lung adenocarcinoma, while CEP55 is related to lung adenocarcinoma prognosis.

CONCLUSION

Taken together, these results indicate that changes in EZH2 expression lead to changes in CEP55 expression in lung adenocarcinoma, and these changes are associated with its prognosis.

microRNA-214 suppresses the growth of cervical cancer cells by targeting EZH2

A number of studies have revealed the significance of microRNAs (miRs) in tumorigenesis. Cervical cancer (CC) is one of the most malignant cancer types and is associated with a poor overall survival rate. A previous study demonstrated a critical role of miR-214 in the development of multiple cancer types, but its role in CC remains elusive. In the current study, miR-214 was observed to be downregulated in CC tissues compared with the adjacent non-cancerous tissue. Overexpression of miR-214 reduced the proliferation of CC cells, whereas inhibiting its expression resulted in enhanced proliferation. Furthermore, Enhancer of zeste homolog 2 (EZH2) was demonstrated to be a direct target of miR-214 in CC. An MTT assay demonstrated that upregulating miR-214 expression or knocking down the expression of EZH2 impaired the proliferation of a CC cell line. Low expression of miR-214 was positively associated with tumor differentiation (P=0.037) and tumor stage (P=0.012). Notably, low expression of miR-214 predicted poor prognosis of patients with CC. Consequently, the results of the current study demonstrated that miR-214 functions as a tumor suppressor in CC and may be regarded as a potential therapeutic target in CC.

A polycomb-mediated epigenetic field defect precedes invasive cervical carcinoma

Human papillomavirus (HPV)-associated cervical carcinoma is preceded by stages of cervical intra-epithelial neoplasia (CIN) that can variably progress to malignancy. Understanding the different molecular processes involved in the progression of pre-malignant CIN is critical to the development of improved predictive and interventional capabilities. We tested the role of regulators of transcription in both the development and the progression of HPV-associated CIN, performing the most comprehensive genomic survey to date of DNA methylation in HPV-associated cervical neoplasia, testing ~2 million loci throughout the human genome in biopsies from 78 HPV+ women, identifying changes starting in early CIN and maintained through carcinogenesis. We identified loci at which DNA methylation is consistently altered, beginning early in the course of neoplastic disease and progressing with disease advancement. While the loss of DNA methylation occurs mostly at intergenic regions, acquisition of DNA methylation is at sites involved in transcriptional regulation, with strong enrichment for targets of polycomb repression. Using an independent cohort from The Cancer Genome Atlas, we validated the loci with increased DNA methylation and found that these regulatory changes were associated with locally decreased gene expression. Secondary validation using immunohistochemistry showed that the progression of neoplasia was associated with increasing polycomb protein expression specifically in the cervical epithelium. We find that perturbations of genomic regulatory processes occur early and persist in cervical carcinoma. The results indicate a polycomb-mediated epigenetic field defect in cervical neoplasia that may represent a target for early, topical interventions using polycomb inhibitors.

Long non-coding RNA LUCAT1 is associated with poor prognosis in human non-small lung cancer and regulates cell proliferation via epigenetically repressing p21 and p57 expression

Recently, long non-coding RNAs (lncRNAs) have been recognized as playing key roles in regulating cellular processes, such as proliferation, invasion, and metastasis. These lncRNAs have been shown to be abnormally expressed in tumorigenic processes. However, the role and clinical relevance of LUCAT1 in non-small-cell lung cancer (NSCLC) remain unclear. In this study, we found that the expression of LUCAT1 was significantly up-regulated in NSCLC tissues compared to non-tumor tissues, and its expression was associated with tumor size, tumor–node–metastasis (TNM) stage and overall survival (OS). Further experiments showed that LUCAT1 knockdown inhibited cell proliferation both in vitro and in vivo. Mechanistic investigations showed that LUCAT1 plays a key role in G0/G1 arrest. We further demonstrated that LUCAT1 was associated with polycomb repressor complexes (PRC2) and that this association was required for epigenetically repression of p21 and p57, thus contributing to the regulation of NSCLC cell cycle and proliferation. In summary, our results show that LUCAT1 could regulate tumorigenesis of NSCLC and be biomarker for poor prognosis in NSCLC.

EZH2-mediated repression of GSK-3β and TP53 promotes Wnt/β-catenin signaling-dependent cell expansion in cervical carcinoma

Enhancer of zeste homolog 2 (EZH2), a catalytic core component of the Polycomb repressive complex 2 (PRC2), stimulates the silencing of target genes through histone H3 lysine 27 trimethylation (H3K27me3). Recent findings have indicated EZH2 is involved in the development and progression of various human cancers. However, the exact mechanism of EZH2 in the promotion of cervical cancer is largely unknown. Here, we show that EZH2 expression gradually increases during the progression of cervical cancer. We identified a significant positive correlation between EZH2 expression and cell proliferation in vitro and tumor formation in vivo by the up-regulation or down-regulation of EZH2 using CRISPR-Cas9-mediated gene editing technology and shRNA in HeLa and SiHa cells. Further investigation indicated that EZH2 protein significantly accelerated the cell cycle transition from the G0/G1 to S phase. TOP/FOP-Flash reporter assay revealed that EZH2 significantly activated Wnt/β-catenin signaling and the target genes of Wnt/β-catenin pathway were up-regulated, including β-catenin, cyclin D1, and c-myc. Moreover, dual-luciferase reporter and chromatin immunoprecipitation (ChIP) assays confirmed that EZH2 inhibited the expression of glycogen synthase kinase-3β (GSK-3β) and TP53 through physically interacting with motifs in the promoters of the GSK-3β and TP53 genes. Additionally, blockage of the Wnt/β-catenin pathway resulted in significant inhibition of cell proliferation, and activation of the Wnt/β-catenin pathway resulted in significant enhancement of cell proliferation, as induced by EZH2. Taken together, our data demonstrate that EZH2 promotes cell proliferation and tumor formation in cervical cancer through activating the Wnt/β-catenin pathway by epigenetic silencing via GSK-3β and TP53.

Expression of EZH2 in endometrial carcinoma and its effects on proliferation and invasion of endometrial carcinoma cells

Expression of enhancer of zeste homolog 2 (EZH2) has been implicated in cancer pathology, but research on its mechanistic activity is limited. The present study sought to assess the levels expression of EZH2 in patients with endometrial carcinoma (EC) and to explore the effects of EZH2 downregulation on the biological behavior of endometrial carcinoma RL-952 cells. Samples were obtained from a total of 104 patients with EC and an immunohistochemical assay was used to detect the expression of EZH2 in cancer and adjacent tissues. The relationship between the expression of EZH2 and the clinicopathological features was analyzed. Endometrial carcinoma RL-952 cells were transfected with chemically synthesized siRNA to conduct targeting inhibition of EZH2 expression. The expression levels of EZH2 protein were detected by immunoblotting. MTT and Transwell assays were used to detect the changes of cell proliferation and invasion after EZH2 downregulation. Of the 104 cases of endometrial carcinoma samples, 71 cases showed positive expression of EZH2, with an expression rate of 68.27%. In 104 cases of adjacent tissue samples, 25 cases showed positive expression of EZH2, with an expression rate of 24.03%. The expression of EZH2 in endometrial carcinoma tissue was significantly higher than that in adjacent tissue (P<0.05). The expression of EZH2 in endometrial carcinoma tissue was not correlated with the menopausal status and age of patients (P>0.05), but was correlated with the histological grade, depth of tumor invasion, lymph node metastasis and TNM stage (P<0.05). The expression of E2H2 was significantly downregulated by si-E2H2 and the proliferation and invasion abilities of cells were significantly reduced after EZH2 downregulation (P<0.05). EZH2 is closely related to the development of endometrial carcinoma and can enhance the proliferative activity of endometrial carcinoma RL-952 cells and promote cell invasion.

MicroRNA-137 is negatively associated with clinical outcome and regulates tumor development through EZH2 in cervical cancer

We intend to evaluate the expression, clinical relevance, and functional role of microRNA-137 (miR-137) in human cervical cancer (CC). MiR-137 expressions were assessed by qPCR in CC cell lines and human CC tumors. The correlation between endogenous miR-137 expression and CC patients' postoperative overall survival was examined statistically. CC cell lines, Ca-Ski, and SiHa cells were transduced with lentivirus to ectopically upregulate endogenous miR-137 expressions. Possible inhibitory effects of miR-137 upregulation on CC in vitro proliferation and migration, as well as in vivo transplantation were evaluated. Targeting of enhancer of zeste homolog 2 (EZH2) gene by miR-137 in CC was assessed by dual-luciferase activity assay and qPCR. In CC cells with upregulated miR-137, EZH2 was overexpressed to assess its direct function in miR-137 mediated CC proliferation and migration. MiR-137 was downregulated in both CC cells and human CC tumors. Downregulation of endogenous miR-137 was significantly correlated with CC patients' short overall survival. In CC cells, miR-137 upregulation is tumor-suppressive by inhibiting proliferation and migration in vitro, and transplantation in vivo. EZH2 was a direct downstream target gene of miR-137 in CC. Forced overexpression of EZH2 in miR-137-upregulated CC cells reversed the tumor-suppression induced by miR-137. MiR-137 is lowly expressed in CC and possibly acting as a negative biomarker for CC patients' clinical outcome. MiR-137 upregulation may suppress CC, very likely by inversely regulating EZH2.

DNA Oncogenic Virus-Induced Oxidative Stress, Genomic Damage, and Aberrant Epigenetic Alterations

Approximately 20% of human cancers is attributable to DNA oncogenic viruses such as human papillomavirus (HPV), hepatitis B virus (HBV), and Epstein-Barr virus (EBV). Unrepaired DNA damage is the most common and overlapping feature of these DNA oncogenic viruses and a source of genomic instability and tumour development. Sustained DNA damage results from unceasing production of reactive oxygen species and activation of inflammasome cascades that trigger genomic changes and increased propensity of epigenetic alterations. Accumulation of epigenetic alterations may interfere with genome-wide cellular signalling machineries and promote malignant transformation leading to cancer development. Untangling and understanding the underlying mechanisms that promote these detrimental effects remain the major objectives for ongoing research and hope for effective virus-induced cancer therapy. Here, we review current literature with an emphasis on how DNA damage influences HPV, HVB, and EBV replication and epigenetic alterations that are associated with carcinogenesis.

Tranilast Inhibits Genes Functionally Involved in Cell Proliferation, Fibrosis, and Epigenetic Regulation and Epigenetically Induces miR-29c Expression in Leiomyoma Cells

Tranilast (N-3,4-dimethoxycinnamoyl anthranilic acid) is an antiallergic agent with inhibitory effects on cell proliferation and extracellular matrix production. Here we assess the effect of tranilast on the expression of miR-29c and genes functionally involved in cell proliferation, fibrosis, and epigenetic regulation in isolated leiomyoma smooth muscle cells (LSMC). Tranilast significantly inhibited the rate of LSMC proliferation, which was associated with downregulation of cell cycle progression genes cyclin D1 (CCND1) and cyclin-dependent kinase 2 (CDK2) expression at messenger RNA and protein levels ( P < .05). Tranilast also suppressed the expression of collagen type I (COL1), collagen type III alpha 1 chain (COL3A1), the profibrotic cytokine, transforming growth factor β-3 (TGF-β3), DNA (cytosine-5)-methyltransferase 1 (DNMT1), and enhancer of zeste homolog 2 (EZH2), which regulate epigenetic status of gene promoters ( P < .05). Tranilast also significantly induced the expression of cellular and secreted miR-29c through downregulation of methylation status of miR-29c promoter ( P < .05). In addition, tranilast suppressed the activity of luciferase reporter containing 3'UTR of COL3A1 and CDK2, which are downstream targets of miR-29c ( P < .05). Knockdown of miR-29c expression attenuated the inhibitory effects of tranilast on COL3A1 and CDK2 protein expression ( P < .05). Collectively, these findings suggest that tranilast could have therapeutic potential as an inhibitory agent for leiomyoma growth and its associated symptoms.

Prognostic value of high EZH2 expression in patients with different types of cancer: a systematic review with meta-analysis

Enhancer of zeste homologue 2 (EZH2) is a potential independent mechanism for epigenetic silencing of tumor suppressor genes in cancer. We conducted an electronic search on PubMed, EMBASE, Web of Science, and Cochrane library to perform this up-to-date meta-analysis. Fifty-one studies with a total of 9444 patients were included. The prevalence of high EZH2 expression was 0.54 (95% CI: 0.47-0.61). High EZH2 expression was significantly associated with poorer prognosis [overall survival: HR 1.54 (95% CI: 1.30-1.78), P < 0.000; disease free survival: HR 1.35 (95% CI: 1.00-1.71), P < 0.000]. In breast cancer, high EZH2 expression correlated with histological types [OR: 1.53 (95CI: 1.13-2.06); P < 0.006], histological grade [OR: 1.62 (95CI: 1.35-1.95); P < 0.000], estrogen receptor (ER) negativity [OR: 2.05 (95CI: 1.67-2.52); P < 0.000], progesterone receptor (PgR) negativity [OR: 1.42 (95CI: 1.03-1.96); P = 0.034], HER-2 positivity [OR: 1.35 (95CI: 1.08-1.69); P = 0.009], and high p53 expression [OR: 1.66 (95CI: 1.07-2.59); P = 0.024]. These results suggest that high EZH2 expression may be a promising prognostic factor to different cancers. High EZH2 expression tends to correlate with pathological types, histological grade, ER negativity, PgR negativity, HER-2 positivity and p53 high expression in breast cancer.

High-Level Expression of RIPK4 and EZH2 Contributes to Lymph Node Metastasis and Predicts Favorable Prognosis in Patients With Cervical Cancer

The investigation of specific genes will establish more useful biomarkers for accurate detection and management of gynecological cancers, especially patients with cervical cancer (CCP). The aim of this study was to evaluate the expression level of RIPK4 and EZH2 messenger RNA (RIPK4 and EZH2 mRNA) in CCP. Expression of RIPK4 and EZH2 in the tissues was determined by immunohistochemistry and qRT-PCR methods. Correlations of RIPK4 and EZH2 mRNA with clinical and pathological parameters were analyzed using the Fisher’s exact test. The mRNA level of RIPK4 was significantly upregulated in tumor tissues compared with matched adjacent normal tissues (4.10 ± 0.89 vs. 1.5 ± 0.82; p = 0.021). EZH2 mRNA was increased in cancer tissues compared to normal tissues (3.54 ± 0.71 vs. 1.2 ± 0.65; p = 0.003). High expression of RIPK4 was observed in 25 patients (64.1%), whereas weak expression was seen in 14 cases (35.9%). Furthermore, the expression of RIPK4 was overexpressed in matched adjacent normal tissues (p = 0.004). FIGO stage and lymph node metastasis were significantly linked to a higher expression of RIPK4 (p < 0.05). Overexpression of EZH2 was found in 30 patients (76.9%) and was associated with FIGO stage, histological type, and lymph node metastasis (p < 0.05). In conclusion, our data suggest that RIPK4/EZH2 markers might be used as potential predictors of prognosis in cervical cancer.

LncRNAs: key players and novel insights into cervical cancer

Cervical cancer contributed the second highest number of deaths in female cancers, exceeded only by breast cancer, carrying high risks of morbidity and mortality. There was a great need and urgency in searching novel treatment targets and prognosis biomarkers to improve the survival rate of cervical cancer patients. Many long non-coding RNAs (lncRNAs) were emerging as pivotal regulators in various biological processes and took vitally an effect on the oncogenesis and progression of cervical cancer. In this review, we summarized the origin and overview function of lncRNAs; highlighted the roles of lncRNAs in cervical cancer in terms of prognosis and tumor progression, invasion and metastasis, apoptosis, and radio-resistance; and outlined the molecular mechanisms of lncRNAs in cervical cancer from the aspects of the interaction of lncRNAs with proteins/mRNAs (especially in HPV protein) and miRNAs, as well as RNA N-methyladenosine (m6A) methylation of lncRNAs. Meanwhile, the application of lncRNAs as biomarkers in cervical cancer prognosis and predictors for metastasis was also discussed. An overview of these researches will be valuable for broadening horizons into mechanisms, selection of meritorious biomarkers for diagnosis as well as prognosis, and future targeted therapy of cervical cancer.

Enhancer of zeste homolog 2 silencing inhibits tumor growth and lung metastasis in osteosarcoma

The enhancer of zeste homolog 2 (EZH2) methyltransferase is the catalytic subunit of polycomb repressive complex 2 (PRC2), which acts as a transcription repressor via the trimethylation of lysine 27 of histone 3 (H3K27me3). EZH2 has been recognised as an oncogene in several types of tumors; however, its role in osteosarcoma has not been fully elucidated. Herein, we show that EZH2 silencing inhibits tumor growth and lung metastasis in osteosarcoma by facilitating re-expression of the imprinting gene tumor-suppressing STF cDNA 3 (TSSC3). Our previous study showed that TSSC3 acts as a tumor suppressor in osteosarcoma. In this study, we found that EZH2 was abnormally elevated in osteosarcoma, and its overexpression was associated with poor prognosis in osteosarcoma. Silencing of EZH2 resulted in tumor growth inhibition, apoptosis and chemosensitivity enhancement. Moreover, suppression of EZH2 markedly inhibited tumor growth and lung metastasis in vivo. Furthermore, EZH2 knockdown facilitated the re-expression of TSSC3 by reducing H3K27me3 in the promoter region. Cotransfection with siEZH2 and siTSSC3 could partially reverse the ability of siEZH2 alone. We have demonstrated that EZH2 plays a crucial role in tumor growth and distant metastasis in osteosarcoma; its oncogenic role is related to its regulation of the expression of TSSC3.

Enhancer of zeste homolog 2 as an independent prognostic marker for cancer: a meta-analysis

Background

Novel biomarkers are of particular interest for predicting cancer prognosis. This study aimed to explore the associations between enhancer of zeste homolog 2 (EZH2) and patient survival in various cancers.

Methods

Relevant literature was retrieved from PubMed and Web of Science databases. Pooled hazard ratios (HRs), odds ratios (ORs), and 95% confidence intervals (CIs) were calculated.

Results

Forty-nine studies (8,050 patients) were included. High EZH2 expression was significantly associated with shorter overall (hazard ratio [HR] 1.74, 95% CI: 1.46–2.07), disease-free (HR 1.59, 95% CI: 1.27–1.99), metastasis-free (HR 2.19, 95% CI: 1.38–3.47), progression-free (HR 2.53, 95% CI: 1.52–4.21), cancer-specific (HR 3.13, 95% CI: 1.70–5.74), and disease-specific (HR 2.29, 95% CI: 1.56–3.35) survival, but not recurrence-free survival (HR 1.38, 95% CI: 0.93–2.06). Moreover, EZH2 expression significantly correlated with distant metastasis (OR 3.25, 95% CI: 1.07–9.87) in esophageal carcinoma; differentiation (OR 3.00, 95% CI: 1.37–6.55) in non-small cell lung cancer; TNM stage (OR 3.18, 95% CI: 2.49–4.08) in renal cell carcinoma; and histological grade (OR 4.50, 95% CI: 3.33–6.09), estrogen receptor status (OR 0.15, 95% CI: 0.11–0.20) and progesterone receptor status (OR 0.30, 95% CI: 0.23–0.39) in breast cancer.

Conclusions

Our results suggested that EZH2 might be an independent prognostic factor for multiple survival measures in different cancers.

Long noncoding RNA PVT1 indicates a poor prognosis of gastric cancer and promotes cell proliferation through epigenetically regulating p15 and p16

BACKGROUND

Mounting evidence indicates that long noncoding RNAs (lncRNAs) could play a pivotal role in cancer biology. However, the overall biological role and clinical significance of PVT1 in gastric carcinogenesis remains largely unknown.

METHODS

Expression of PVT1 was analyzed in 80 GC tissues and cell lines by qRT-PCR. The effect of PVT1 on proliferation was evaluated by MTT and colony formation assays, and cell apoptosis was evaluated by Flow-cytometric analysis. GC cells transfected with shPVT1 were injected into nude mice to study the effect of PVT1 on tumorigenesis in vivo. RIP was performed to confirm the interaction between PVT1 and EZH2. ChIP was used to study the promoter region of related genes.

RESULTS

The higher expression of PVT1 was significantly correlated with deeper invasion depth and advanced TNM stage. Multivariate analyses revealed that PVT1 expression served as an independent predictor for overall survival (p = 0.031). Further experiments demonstrated that PVT1 knockdown significantly inhibited the proliferation both in vitro and in vivo. Importantly, we also showed that PVT1 played a key role in G1 arrest. Moreover, we further confirmed that PVT1 was associated with enhancer of zeste homolog 2 (EZH2) and that this association was required for the repression of p15 and p16. To our knowledge, this is the first report showed that the role and the mechanism of PVT1 in the progression of gastric cancer.

CONCLUSIONS

Together, these results suggest that lncRNA PVT1 may serve as a candidate prognostic biomarker and target for new therapies in human gastric cancer.

URG4 overexpression is correlated with cervical cancer progression and poor prognosis in patients with early-stage cervical cancer

Background

Upregulator of cell proliferation 4 (URG4) has been implicated in the oncogenesis of certain cancers. However, the correlation between URG4 expression and clinicopathological significance in human cancer remains unclear. Therefore, this study investigated its expression and clinicopathological significance in cervical cancer patients.

Methods

URG4 expression was examined using quantitative PCR (qPCR) and western blotting in normal cervical epithelial cells, cervical cancer cells, and eight matched pairs of cervical cancer tissues and adjacent noncancerous tissues from the same patient. In addition, immunohistochemistry (IHC) was used to examine URG4 expression in paraffin-embedded tissues from 167 cervical cancer patients (FIGO stages Ib1-IIa2). Statistical analyses were performed to evaluate associations between URG4 expression and prognostic and diagnostic factors.

Results

URG4 was significantly upregulated in the cervical cancer cell lines and tissues compared with the normal cells and adjacent noncancerous cervical tissues. IHC revealed high URG4 expression in 59 out of the 167 (35.13%) cervical cancer specimens. Its expression was significantly correlated with clinical stage (P < 0.0001), tumour size (P = 0.012), T classification (P = 0.023), lymph node metastasis (P = 0.001) and vaginal involvement (P = 0.002). Patients with high URG4 expression, particularly those who received concurrent chemotherapy and radiotherapy (P < 0.0001), showed a shorter overall survival (OS) and disease-free survival (DFS) compared to those with the low expression of this protein. Multivariate analysis revealed that URG4 expression is an independent prognostic factor for cervical cancer patients.

Conclusions

Our results demonstrated that elevated URG4 protein expression is associated with a poor outcome in patients with early-stage cervical cancer. URG4 may be a novel prognostic marker and therapeutic target for the treatment of cervical cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-885) contains supplementary material, which is available to authorized users.

PCI-24781 down-regulates EZH2 expression and then promotes glioma apoptosis by suppressing the PIK3K/Akt/mTOR pathway

PCI-24781 is a novel histone deacetylase inhibitor that inhibits tumor proliferation and promotes cell apoptosis. However, it is unclear whether PCI-24781 inhibits Enhancer of Zeste 2 (EZH2) expression in malignant gliomas. In this work, three glioma cell lines were incubated with various concentrations of PCI-24781 (0, 0.25, 0.5, 1, 2.5 and 5 μM) and analyzed for cell proliferation by the MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay and colony formation, and cell cycle and apoptosis were assessed by flow cytometry. The expression of EZH2 and apoptosis-related proteins was assessed by western blotting. Malignant glioma cells were also transfected with EZH2 siRNA to examine how PCI-24781 suppresses tumor cells. EZH2 was highly expressed in the three glioma cell lines. Incubation with PCI-24781 reduced cell proliferation and increased cell apoptosis by down-regulating EZH2 in a concentration-dependent manner. These effects were simulated by EZH2 siRNA. In addition, PCI-24781 or EZH2 siRNA accelerated cell apoptosis by down-regulating the expression of AKT, mTOR, p70 ribosomal protein S6 kinase (p70s6k), glycogen synthase kinase 3A and B (GSK3a/b) and eukaryotic initiation factor 4E binding protein 1 (4E-BP1). These data suggest that PCI-24781 may be a promising therapeutic agent for treating gliomas by down-regulating EZH2 which promotes cell apoptosis by suppressing the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of the rapamycin (mTOR) pathway.

Prognostic histopathological and molecular markers on prostate cancer needle-biopsies: a review

Prostate cancer is diverse in clinical presentation, histopathological tumor growth patterns, and survival. Therefore, individual assessment of a tumor's aggressive potential is crucial for clinical decision-making in men with prostate cancer. To date a large number of prognostic markers for prostate cancer have been described, most of them based on radical prostatectomy specimens. However, in order to affect clinical decision-making, validation of respective markers in pretreatment diagnostic needle-biopsies is essential. Here, we discuss established and promising histopathological and molecular parameters in diagnostic needle-biopsies.