High EZH2 Expression Research Articles

Combined inhibition of histone methyltransferases EZH2 and DOT1L is an effective therapy for neuroblastoma.

The child cancer, neuroblastoma (NB), is characterised by a low incidence of mutations and strong oncogenic embryonal driver signals. Many new targeted epigenetic modifier drugs have failed in human trials as monotherapy. We performed a high-throughput, combination chromatin-modifier drug screen against NB cells. We screened 13 drug candidates in 78 unique combinations. We found that the combination of two histone methyltransferase (HMT) inhibitors: GSK343, targeting EZH2, and SGC0946, targeting DOT1L, demonstrated the strongest synergy across 8 NB cell lines, with low normal fibroblast toxicity. High mRNA expression of both EZH2 and DOT1L in NB tumour samples correlated with the poorest patient survival. Combination HMT inhibitor treatment caused activation of ATF4-mediated endoplasmic reticulum (ER) stress responses. In addition, glutathione and several amino acids were depleted by HMT inhibitor combination on mass spectrometry analysis. The combination of SGC0946 and GSK343 reduced tumour growth in comparison to single agents. Our results support further investigation of HMT inhibitor combinations as a therapeutic approach in NB.

Resectable Non-Small Cell Lung Cancer Heterogeneity and Recurrence Assessed by Tissue Next-Generation Sequencing Genotyping and Circulating Tumor Cell EZH2 Characterization

IntroductionNon-small cell lung cancer (NSCLC) is the most common type of lung neoplasm. Despite surgical resection, it has a high relapse rate, accounting for 30–55% of all cases. Next-generation sequencing (NGS) based on a customized gene panel and the analysis of circulating tumor cells (CTCs) can help identify heterogeneity, stratify high-risk patients, and guide treatment decisions. In this descriptive study involving a small prospective cohort, we focus on the phenotypic characterization of CTCs, particularly concerning EZH2 expression (a member of the Polycomb Repression Complex 2), as well as on the mutation profiles of the tissue using a customized gene panel and their association with poor outcomes in NSCLC. MethodsIsolation and characterization of EZH2 on CTCs were evaluated before surgical resection (CTC1) and one month after surgery (CTC2) in resectable NSCLC patients. Targeted NGS was performed using a customized 50-gene panel on tissue samples from a subset of patients. Results76 patients with resectable NSCLC were recruited. The top mutated genes in the cohort included TP53, FLT1, MUC5AC, EGFR, and NLRP3. Pair of genes that had mutually exclusive mutations was TP53-RIN3, and pairs of genes with co-occurring mutations were CD163-TLR4, FGF10-FOXP2, ADAMTSL3-FLT1, ADAMTSL3-MUC5AC and MUC5AC-NLRP3. CTCs decreased significantly between the two time points CTC1 and CTC2 (p<0.0001), and CTCs+ patients with high EZH2 expression had an 87% increased risk of death (p=0.018). ConclusionsIntegrating molecular profiling of tumors and CTC characterization can provide valuable insights into tumor heterogeneity and improve patient stratification for resectable NSCLC.

Relationship between EZH2 expression and prognosis of patients with hepatocellular carcinoma using a pathomics predictive model

BackgroundEnhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) is overexpressed in hepatocellular carcinoma, promoting tumorigenesis and correlating with poor prognosis. Traditional histopathological examinations are insufficient to accurately predict hepatocellular carcinoma (HCC) survival; however, pathomics models can predict EZH2 expression and HCC prognosis. This study aimed to investigate the relationship between pathomics features and EZH2 expression for predicting overall survival of patients with HCC. MethodsWe analyzed 267 patients with HCC from the Cancer Genome Atlas database, with available pathological images and gene expression data. RNA sequencing data were divided into high and low EZH2 expression groups for prognosis and survival analysis. Pathological image features were screened using mRMR_RFE. A pathological model was constructed using a gradient boosting machine (GBM) algorithm, and efficiency evaluation and survival analysis of the model were performed. The R package “survminer” took the pathomics score (PS) cutoff value of 0.4628 to divide the patients into two groups: high and low PS expression. Survival analyses included Kaplan–Meier curve analysis, univariate and multivariate Cox regression analyses, and interaction tests. Potential pathomechanisms were explored through enrichment, differential, immune cell infiltration abundance, and gene mutation analyses. ResultEZH2 was highly expressed in tumor samples but poorly expressed in normal tissue samples. Univariate and multivariate Cox regression analyses revealed that EZH2 was an independent risk factor for HCC (hazard ratio [HR], 2.792 and 3.042, respectively). Seven imaging features were selected to construct a pathomics model to predict EZH2. Decision curve analysis showed that the model had high clinical utility. Multivariate Cox regression analysis showed that high PS expression was an independent risk factor for HCC prognosis (HR, 2.446). The Kaplan–Meier curve showed that high PS expression was a risk factor for overall survival. ConclusionEZH2 expression can affect the prognosis of patients with liver cancer. Our pathological model could predict EZH2 expression and prognosis of patients with HCC with high accuracy and robustness, making it a new and potentially valuable tool.

Gain of chromosome 8q and high expression of EZH2 may predict poor prognosis in Chinese patients with uveal melanoma

PurposeTo explore risk factors predicting poor prognosis of uveal melanoma in a Chinese population, with specific emphasis on monosomy 3, 8q gain, and EZH2 staining. MethodsEighty-nine patients with uveal melanoma from 2012 to 2021 were reviewed. Clinical and pathological records were collected and analyzed. Immunohistochemical staining of EZH2, monosomy 3 and 8q gain were respectively conducted in 45, 54, and 57 cases. Survival was evaluated by Kaplan–Meier analysis and log-rank test. Cox proportional hazard regressions were employed to predict risk factors of distant metastasis. ResultsThe median follow-up was 44 months. Altogether, 16 % of patients developed distant metastases and died from disease-related causes. Disease-specific survival at one and three years was 96.6 % and 88.4 % while distant metastasis rates were 7.9 % and 12 %. Univariate Cox regression analysis revealed that age (HR: 1.04), tumor largest basal diameter (HR: 1.21), tumor thickness (HR: 1.21), ciliary body involvement (HR: 3.50), AJCC stage (HR: 5.68), epithelioid cell type (HR: 7.71), 8q gain (HR: 7.48), and high expression of EZH2 (HR: 6.09) were associated with distant metastasis. 8q gain was associated with epithelioid cell type and thicker tumor while EZH2 was correlated with epithelioid cell type. Monosomy 3 lacked a significant correlation with other factors. ConclusionEZH2 and 8q gain could be taken into consideration when calculating poor prognosis in Chinese patients with uveal melanoma. Monosomy 3 showed no significance in distant metastasis, but this may be due to a small sample size.

Computed tomography-based radiomics predicts the fibroblast-related gene EZH2 expression level and survival of hepatocellular carcinoma

BACKGROUND Hepatocellular carcinoma (HCC) is the most common subtype of liver cancer. The primary treatment strategies for HCC currently include liver transplantation and surgical resection. However, these methods often yield unsatisfactory outcomes, leading to a poor prognosis for many patients. This underscores the urgent need to identify and evaluate novel therapeutic targets that can improve the prognosis and survival rate of HCC patients. AIM To construct a radiomics model that can accurately predict the EZH2 expression in HCC. METHODS Gene expression, clinical parameters, HCC-related radiomics, and fibroblast-related genes were acquired from public databases. A gene model was developed, and its clinical efficacy was assessed statistically. Drug sensitivity analysis was conducted with identified hub genes. Radiomics features were extracted and machine learning algorithms were employed to generate a radiomics model related to the hub genes. A nomogram was used to illustrate the prognostic significance of the computed Radscore and the hub genes in the context of HCC patient outcomes. RESULTS EZH2 and NRAS were independent predictors for prognosis of HCC and were utilized to construct a predictive gene model. This model demonstrated robust performance in diagnosing HCC and predicted an unfavorable prognosis. A negative correlation was observed between EZH2 expression and drug sensitivity. Elevated EZH2 expression was linked to poorer prognosis, and its diagnostic value in HCC surpassed that of the risk model. A radiomics model, developed using a logistic algorithm, also showed superior efficiency in predicting EZH2 expression. The Radscore was higher in the group with high EZH2 expression. A nomogram was constructed to visually demonstrate the significant roles of the radiomics model and EZH2 expression in predicting the overall survival of HCC patients. CONCLUSION EZH2 plays significant roles in diagnosing HCC and therapeutic efficacy. A radiomics model, developed using a logistic algorithm, efficiently predicted EZH2 expression and exhibited strong correlation with HCC prognosis.

Abstract PO4-16-01: EZH2 is Overexpressed in Invasive Carcinoma and DCIS in both BRCA1 and BRCA2 Mutation Carriers

Abstract Background The transcriptional repressor EZH2 (Polycomb Group Protein Enhancer of Zeste Homologue 2) is overexpressed in multiple neoplasms including breast cancer where it associates with high proliferation, aggressive features and poor prognosis and is of interest as a potential therapeutic target. EZH2 nuclear expression in breast cancer has been shown to correlate specifically with high tumor grade and basal-like histologic features but has not been well studied in cancers from BRCA carriers. Here we evaluate the expression of EZH2 protein in BRCA-associated invasive breast carcinomas and precursor lesions. Methods Eighteen cases of invasive breast cancer in consented BRCA carriers (8 BRCA1 and 10 BRCA2) treated at Dana Farber Cancer Institute from 2001-2019 were reviewed by two pathologists (TAD and RBPP). Histopathologic features (histologic subtype, nuclear grade, mitotic score) and presence of precursor lesions were recorded. Immunohistochemistry for EZH2 was performed on freshly cut formalin-fixed paraffin-embedded tissue sections (1-3 sections/case) using a monoclonal antibody against EZH2 (D2C9, Cell Signaling). Nuclear EZH2 expression was scored as negative (score=1, no staining); weak (score 2, &amp;lt; 25%); moderate (score=3, 25–75%); and strong (score=4, &amp;gt;75%), of any intensity following published criteria. EZH2 overexpression was defined as scores 3 and 4. Results The majority of the invasive carcinomas showed grade III histology (13/18, 72%), as expected. Of 8 BRCA1 cases, 6 were classified as grade III (75%), 1 as grade II, and 1 as grade I (7 cases of invasive ductal carcinoma and 1 case of invasive tubular carcinoma). Of 10 BRCA2 cases, 7 were classified as grade III (70%) and 3 as grade II (30%) (5 cases of invasive ductal carcinoma and 5 cases of invasive carcinoma with ductal and lobular features). The majority of cases (13 of 18, 72%) showed high expression of EZH2 in the invasive carcinoma (6 BRCA1 and 7 BRCA2 cases; 2 grade II and 11 grade III). Of 13 cases with EZH2 overexpression, 6 were ER+/PR+/HER2- and 7 were triple negative, with 9 invasive ductal carcinomas and 4 invasive carcinomas with ductal and lobular features. Of 5 cases with no/low EZH2 overexpression, 1 was ER+/PR+/HER2-, 3 were ER+/PR-/HER2- and 1 was triple negative, with 3 invasive ductal carcinomas, 1 invasive carcinoma with ductal and lobular features and 1 invasive tubular carcinoma. In all cases with adjacent ductal carcinoma in situ (DCIS) (n=14), the pattern of EZH2 expression in the DCIS was identical to that seen in the invasive carcinoma (11 high and 3 low expression). Overexpression of EZH2 was not observed in any other precursor lesions (LCIS, ADH, ALH) or in normal tissue. Conclusion EZH2 protein overexpression is seen in the majority of invasive carcinomas in BRCA carriers, both in BRCA1 and in BRCA2. In all cases, the associated DCIS shows the same pattern of expression as the invasive carcinoma, suggesting that overexpression occurs early in tumorigenesis, while tumor cells are still confined within the ducts. The high rate of overexpression of EZH2 in BRCA1- and BRCA2-associated tumors suggests a potential role for EZH2 as a target and/or a biomarker in these cancers. Citation Format: Tabata Alves Domingos, Roberto Bonfim Pimenta Peixoto, Rodrigo Fonseca Abreu, Ashka Patel, Krishan Taneja, McKenna Moore, Celina Kleer, Deborah Dillon. EZH2 is Overexpressed in Invasive Carcinoma and DCIS in both BRCA1 and BRCA2 Mutation Carriers [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-16-01.

MiR-600 mediates EZH2/RUNX3 signal axis to modulate breast cancer cell viability and sorafenib sensitivity.

Breast cancer (BC) ranks as the most prevalent gynecologic tumor globally. Abnormal expression of miRNAs is concerned with the development of cancers such as BC. However, little is known about the role of miR-600 in BC. This work aimed to explore the role of miR-600 in the malignant progression and sorafenib sensitivity of BC cells. Expression and interaction of miR-600/EZH2/RUNX3 were analyzed by bioinformatics. qRT-PCR was utilized to assay RNA expression of miR-600 and mRNA expression of EZH2/RUNX3. The binding relationship between miR-600 and EZH2 was tested by dual luciferase assay and RNA immunoprecipitation (RIP). The effects of miR-600/EZH2/RUNX3 axis on the malignant behavior and sorafenib sensitivity of BC cells were detected by CCK-8 and colony formation assay. Low expression of miR-600 and RUNX3 in BC was found by bioinformatics and molecular assays. High expression of EZH2 in BC was negatively correlated with RUVX3. Dual luciferase assay and RIP demonstrated that MiR-600 could bind to EZH2. Cell assays displayed that miR-600 knockdown could foster the malignant progression of BC cells and reduce the sensitivity of BC cells to sorafenib. EZH2 knockdown or RUNX3 overexpression could offset the effect of miR-600 inhibitor on the malignant behavior and sorafenib sensitivity of BC cells. MiR-600 can hinder the malignant behavior of BC cells and foster sensitivity of BC cells to sorafenib via EZH2/RUNX3 axis, exhibiting themiR-600/EZH2/RUNX3 axis as a feasible therapeutic target for BC patients.

Epigenetic Modifiers MMSET and EZH2 Physically Interact and Cooperate to Support Multiple Myeloma Pathophysiology

Multiple myeloma (MM) is a malignant B cell dyscrasia characterized by the accumulation of clonal plasma cells (PC) within the bone marrow (1). Genome sequencing studies have revealed great heterogeneity and genomic instability, a complex mutational landscape and a branching pattern of clonal evolution (2-4). Epigenetic factors are also involved in MM initiation, progression, and occurrence of chemoresistance (5). Among them, EZH2 and MMSET are associated with poor prognosis values and contribute to MM disease. EZH2 is the main catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) and deposits H3K27me3 on chromatin (6), whereas MMSET, coded by the gene NSD2, which is the target oncogene of t(4;14) primary translocation, is a histone methyltransferase that methylates H3K36me2 (7). Using proteomics analysis of EZH2-immune precipitates, we identified a constitutive interaction between EZH2 and MMSET independently of t(4;14) translocation and mutational status of EZH2 in MM cells. Furthermore, MAK-683, an allosteric inhibitor of EZH2, disrupted this interaction, but not EPZ-6438, a catalytic inhibitor of EZH2, suggesting that MMSET-EZH2 interaction may be mediated by other PRC2 factors, but is independent of the PRC2 activity. Analysis of EZH2 expression levels and t(4;14) translocation status in 3 independent cohorts of MM patients (CoMMPass (N=674), UAMS-TT2 (N=345), Mtp-Daratumumab (N=51)) identified a worse overall survival of patients with high EZH2 expression combined with t(4;14) chromosomal translocation than patients with only one of these genetic events. We identified 355 differentially expressed genes in this “ EZH2 High t(4;14) +” subgroup compared to other patients. GSEA analysis of up-regulated genes in this subgroup identified a significant enrichment for genes involved in cell cycle, KRAS signaling, Cell-Cell signaling, Hypoxia and Epithelial-Mesenchymal transition. These results indicate that EZH2-MMSET interaction is of clinical interest in t(4;14) MM patients. To better understand the molecular relationship between EZH2 and MMSET, we generated MMSET-depleted clones by CRISPR-Cas9. MMSET depletion did not significantly alter cell proliferation and survival, but reduced the clonogenic capacity of MM cells compared to non-depleted cells. Moreover, after IL-6 or serum starvation, IL-6 and IGF-1 sensitivity was significantly affected in MMSET-depleted clones compared to the parental cell line, indicating that MMSET overexpression confers a cell growth advantage to MM cells under stress conditions and an independence of growth factors produced by bone marrow microenvironment Additionally, MMSET depletion induced changes in PRC2 nuclear localization in MM cells, a decrease of H3K36me3 and a concomitant increase in H3K27me3 levels, which altered the transcriptional program of cells showing, among others, a specific enrichment in genes up-regulated in t(4;14) MM subgroup of patients. Finally, we demonstrated that disrupting EZH2-MMSET interaction with MAK-683 may be of therapeutic interest, since MAK-683 combination with conventional drugs used in MM treatment, including melphalan and Panobinostat or BRD4 inhibitors, synergized to kill MM cells. Taken together, our data identified an “ EZH2 High t(4;14) +” signature in MM patients with a poor outcome who may benefit from combination therapy of MAK-683 with melphalan or epidrugs.

Phosphorylation of EZH2 differs HER2-positive breast cancer invasiveness in a site-specific manner

HER2-positive breast cancer (BC) invasiveness and drug-resistance issue is the critical treatment obstacle recently. We investigated the total and phosphorylated status EZH2 expression in database and BC tissue microarray. We demonstrated for the first time that EZH2 is distributed both in cytoplasm and nucleus of breast cancer cells in a phosphorylation site-specific manner. High expressed-EZH2 cases more frequently had an advanced clinical stage (lymph node metastasis) and aggressive features than EZH2-low cases, potentially indicating the high risk of HER2-positive BC (p < 0.05). Notably, highly expressed phosphorylated EZH2 is differently located in cytoplasm or nucleus in a site-specific manner in breast cancer cells. Nucleus-located pEZH2-S21 is expressed in invasive and lymph node metastatic HER2-positive BC cases (p = 0.144, p = 0.001). Cytoplasmic pEZH2-T487 is correlated with HER2 positive status (p = 0.014).In conclusion, high expression of nucleus-located EZH2 might be a predictor of invasive BC. Activation of phosphorylated EZH2-S21 site in nucleus would be a potential predictor of HER2-positve BC and poor efficacy of HER2-target therapy. These results point to a PRC2-independent non-epigenetic mechanism and therapeutic strategy of EZH2 in HER2-positive BC.

The clinicopathological and prognostic significances of EZH2 expression in urological cancers: A meta‑analysis and bioinformatics analysis.

The Drosophila zeste enhancer homolog 2 gene (enhancer of zeste homolog 2; EZH2) is an important member of the polycomb group (PcG) gene family, which maintains the homologous gene via chromosome modification during embryonic development. EZH2 is overexpressed in various tumors, is closely related to tumor formation and growth, and has a malignant phenotype that promotes tumor cell proliferation, proliferation and metastasis. In the present study, a meta- and bioinformatic analysis was performed using data from multiple online databases until August 30, 2022. EZH2 upregulation was found in kidney, bladder and prostate cancers. EZH2 expression was negatively related to TNM staging and pathological grade in kidney and prostate cancers (P<0.05), as well as invasion depth and pathological grade in bladder cancer. According to the KM-plotter database, EZH2 expression was inversely associated with poor overall survival in patients with kidney clear cell renal cell carcinoma (RCC) and papillary RCC and with favorable survival in bladder cancer. EZH2 expression was negatively related to relapse-free survival in kidney papillary RCC and bladder cancer but positively associated with kidney clear cell RCC. According to GEPIA and UALCAN databases, EZH2 expression was higher in tumor tissue than normal tissue. The TIMER database showed that EZH2 was closely associated with the proportion of seven immune cell infiltrates in kidney, bladder, and prostate cancers. High EZH2 expression may be a potential marker of tumorigenesis and metastasis in patients with urological cancers.

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

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

EZH2 mediated metabolic rewiring promotes tumor growth independently of histone methyltransferase activity in ovarian cancer

BackgroundEnhancer of zeste homolog 2 (EZH2), the key catalytic subunit of polycomb repressive complex 2 (PRC2), is overexpressed and plays an oncogenic role in various cancers through catalysis-dependent or catalysis-independent pathways. However, the related mechanisms contributing to ovarian cancer (OC) are not well understood.MethodsThe levels of EZH2 and H3K27me3 were evaluated in 105 OC patients by immunohistochemistry (IHC) staining, and these patients were stratified based on these levels. Canonical and noncanonical binding sites of EZH2 were defined by chromatin immunoprecipitation sequencing (ChIP-Seq). The EZH2 solo targets were obtained by integrative analysis of ChIP-Seq and RNA sequencing data. In vitro and in vivo experiments were performed to determine the role of EZH2 in OC growth.ResultsWe showed that a subgroup of OC patients with high EZH2 expression but low H3K27me3 exhibited the worst prognosis, with limited therapeutic options. We demonstrated that induction of EZH2 degradation but not catalytic inhibition profoundly blocked OC cell proliferation and tumorigenicity in vitro and in vivo. Integrative analysis of genome-wide chromatin and transcriptome profiles revealed extensive EZH2 occupancy not only at genomic loci marked by H3K27me3 but also at promoters independent of PRC2, indicating a noncanonical role of EZH2 in OC. Mechanistically, EZH2 transcriptionally upregulated IDH2 to potentiate metabolic rewiring by enhancing tricarboxylic acid cycle (TCA cycle) activity, which contributed to the growth of OC.ConclusionsThese data reveal a novel oncogenic role of EZH2 in OC and identify potential therapeutic strategies for OC by targeting the noncatalytic activity of EZH2.

The chromosomal instability 25 gene signature is identified in clear cell renal cell carcinoma and serves as a predictor for survival and Sunitinib response.

Chromosomal instability (CIN) is a cancer hallmark and it is difficult to directly measure its phenotype, while a CIN25 gene signature was established to do so in several cancer types. However, it is currently unclear whether there exists this signature in clear cell renal cell carcinoma (ccRCC), and if so, which biological and clinical implications it has. Transcriptomic profiling was performed on 10 ccRCC tumors and matched renal non-tumorous tissues (NTs) for CIN25 signature analyses. TCGA and E-MBAT1980 ccRCC cohorts were analyzed for the presence of CIN25 signature, CIN25 score-based ccRCC classification, and association with molecular alterations and overall or progression-free survival (OS or PFS). IMmotion150 and 151 cohorts of ccRCC patients treated with Sunitinib were analyzed for the CIN25 impact on Sunitinib response and survival. The transcriptomic analysis of 10 patient samples showed robustly upregulated expression of the CIN25 signature genes in ccRCC tumors, which were further confirmed in TCGA and E-MBAT1980 ccRCC cohorts. Based on their expression heterogeneity, ccRCC tumors were categorized into CIN25-C1 (low) and C2 (high) subtypes. The CIN25-C2 subtype was associated with significantly shorter patient OS and PFS, and characterized by increased telomerase activity, proliferation, stemness and EMT. The CIN25 signature reflects not only a CIN phenotype, but also levels of the whole genomic instability including mutation burden, microsatellite instability and homologous recombination deficiency (HRD). Importantly, the CIN25 score was significantly associated with Sunitinib response and survival. In IMmotion151 cohort, patients in the CIN25-C1 group exhibited 2-fold higher remission rate than those in the CIN25-C2 group (P = 0.0004) and median PFS in these two groups was 11.2 and 5.6 months, respectively (P = 7.78E-08). Similar results were obtained from the IMmotion150 cohort analysis. Higher EZH2 expression and poor angiogenesis, well characterized factors leading to Sunitinib resistance, were enriched in the CIN25-C2 tumors. The CIN25 signature identified in ccRCC serves as a biomarker for CIN and other genome instability phenotypes and predicts patient outcomes and response to Sunitinib treatment. A PCR quantification is enough for the CIN25-based ccRCC classification, which holds great promises in clinical routine application.

Abstract 6139: Clinical implication of EZH2 inhibitors in hepatocellular carcinoma

Abstract Background &amp; Aim: Aberrant upregulation of EZH2 is frequently observed in hepatocellular carcinoma (HCC) and significantly associated with poor prognosis of HCC patients. While EZH2 inhibitors (EZH2i) are recently approved for treatment of lymphoma and sarcoma, their antitumor effect alone is not optimally efficacious against solid tumors like HCC. Ferroptosis is a newly discovered nonapoptotic type of cell death characterized by the iron-dependent accumulation of lipid hydroperoxides in cell membrane to lethal levels. Owing to anti-cancer effects of ferroptosis, many oncogenes are known to suppress ferroptosis. However, their mechanisms in HCC are currently unknown. We aim to uncover a novel mechanism for EZH2-mediated resistance to ferroptosis in HCC. Methods: Multi-step analyses were performed with genomic data from mouse models (Ezh1/2 KO), cancer cell lines treated with EZH2i GSK126, and primary tumors including HCC to identify genetic networks or signaling/metabolic pathways associated with EZH2 in cancer cells. Functional connection of identified networks or pathways from the prediction analyses was tested in cell line models with various molecular biology approaches including western blots, colony forming assay, overexpression and/or depletion of genes of interest. Results: Gene network analysis predicted that ferroptosis pathway is inhibited by EZH2. Interestingly, lipid biosynthesis is also identified as an inhibited metabolic pathway by EZH2. Since polyunsaturated fatty acid (PUFA) is essential for executing ferroptosis, we hypothesize that EZH2 suppresses ferroptosis by inhibiting synthesis of PUFA. HCC cells with high EZH2 expression have higher IC50 values to erastin, a ferroptosis inducer, than those with low EZH2 expression. Moreover, inhibition or depletion of EZH2 sensitize HCC cells to erastin-induced ferroptotic cell death, strongly suggesting that EZH2 accounts for resistance to ferroptosis. Mechanistically, EZH2 increases H3K27me3 methylation near PUFA gene promoters, leading to suppression of PUFA gene expression and subsequently low cellular PUFA level. Most interestingly, treatment of EZH2i significantly sensitized HCC cells with high EZH2 expression to erastin-induced ferroptosis, suggesting potential therapeutic opportunity for treatment of HCC patients with high EZH2 expression. Conclusion: EZH2 is a novel suppressor of ferroptosis by negatively regulating lipid metabolism. Thus, our study provides scientific evidence for developing a novel therapeutic strategy for treatment of HCC patients with co-treatment of ferroptosis inducers and EZH2 inhibitors. Citation Format: Bo Hwa Sohn, Sung Hwan Lee, Yun Seong Jeong, Ju-Seog Lee. Clinical implication of EZH2 inhibitors in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6139.

Amino-Modified Magnetic Nanoparticles Used in Exploring the Mechanism of CCL18-Induced H19 Upregulation that Promotes Breast Cancer Cell Invasion by Regulating the EZH2-Mediated Repression of E-Cadherin Expression

The acceleration of Chemokine (C–C motif) ligand 18 (CCL18) and long noncoding RNA H19 expression is reportedly closely associated with breast cancer (BC) development and progression; however, the underlying mechanism and clinical value between CCL18 and H19 in BC remain unclear. Hence, this study aimed to examine the expression and function of CCL18 and H19 in BC tissues and cells by real-time polymerase chain reaction, immunohistochemistry, and other methods. We also detected the binding of EZH2 and other proteins to H19 through nanomagnetic bead immunoprecipitation and analyzed the roles of CCL18 and H19 in BC progression and their underlying mechanisms. Both CCL18 and H19 were upregulated in BC tissues and cell lines. High expression of CCL18 and EZH2 was closely associated with short survival in patients with BC. CCL18 or H19 silencing can prohibit BC cell invasion. Moreover, CCL18 accelerated the invasiveness of BC cells dose-dependently, and its expression was positively related to H19 expression in BC tissues. CCL18 enhanced H19 expression, while H19 knockdown partially ameliorated CCL18-induced BC cell invasiveness. Mechanistically, H19 can directly bind with EZH2 and mediate its accumulation at the promoter region of E-cadherin genes, consequently inhibiting E-cadherin expression. In conclusion, CCL18 promotes BC progression by enhancing H19 expression, and H19 overexpression suppresses E-cadherin expression via EZH2-mediated inhibition. Thus, this study describes a potential biomarker for the diagnosis, prognosis, and treatment of BC.

OGC P21 EZH2: A novel therapeutic target in oesophageal adenocarcinoma

Abstract Background Enhancer of zeste homologue 2 (EZH2), the catalytic subunit of the histone lysine methyltransferase Polycomb Repressor Complex 2 (PRC2), mediates gene silencing of target genes epigenetically. It is over-expressed and associated with poor outcomes in numerous malignancies. EZH2 inhibitors are currently used in the treatment of follicular lymphomas and epithelioid sarcomas. Oesophageal adenocarcinoma (OAC) has predicted sensitivity to EZH2 inhibition due to the high prevalence of potentially sensitizing mutations. This in vitro study aimed to assess the efficacy of EZH2 inhibitors in the treatment of OAC. Methods Bioinformatical analysis of publicly available bulk RNA transcriptomic data from OAC samples included in the Cancer Genome Atlas (TCGA) database was carried out. OAC cell lines OE33, FLO1 and MFD1 cultured in 2D were treated with a panel of EZH2 inhibitors at a range of clinically relevant concentrations either as monotherapies or in combination with OAC standard of care (SOC) chemotherapies. Cell viability was assessed via colorimetric MTS assay at 72hrs and 6 days post-treatment. Results Median EZH2 mRNA expression levels calculated from OAC TCGA data were significantly greater than EZH2 mRNA expression in normal oesophageal tissue (p&amp;lt;0.01). OAC patients with high EZH2 expression had reduced median overall survival compared to patients with low EZH2 expression (13.1 months vs 32 months, p= 0.03). EZH2 inhibitors demonstrated efficacy as monotherapies in all 3 cell lines. EZH2 inhibitors in combination with 5-fluorouracil (5-FU) showed greater efficacy than 5-FU alone, demonstrated by reductions in 5-FU half-maximal inhibitory concentration (IC50) values. Conclusions These early in vitro results demonstrate the potential of EZH2 inhibition as a novel therapy in OAC, particularly in combination with current chemotherapy agents. Further in vitro work is focused on their efficacy in patient derived tumour organoid models.

Analysis of the correlation between Zeste enhancer homolog 2 (EZH2) mRNA expression and the prognosis of mesothelioma patients and immune infiltration

Mesothelioma lies one of the most malignant tumors, in which the identification of the corresponding biomarkers is extremely critical. This study aims to investigate the prognostic value of enhancer homolog 2 (EZH2) mRNA expression in mesothelioma patients accompanied with its immune infiltration analysis. Gene expression, clinical information and enrichment analysis were obtained based on the Cancer Genome Atlas (TCGA), the immune infiltration analysis and bioinformatics analysis were performed. Clinical information and gene expression were obtained from 86 patients with mesothelioma based on TCGA database. Survival analysis, GSEA enrichment analysis, and immune infiltration analysis of EZH2 expression were carried out using R (version 3.6.3) (statistical analysis and visualization). The correlation of EZH2 expression with immune cell infiltration in mesothelioma was analyzed according to the TIMER database (Fig. https://cistrome.shinyapps.io/timer/). A univariate and multivariate analysis of general data obtained from the TCGA database was performed, involving age, gender, stage, pathological type, and whether they had received radiotherapy, the results indicated the association of high expression of EZH2 with poor prognosis in mesothelioma patients, with the worse prognosis in the High group (HR = 2.75, 95% CI 1.68–4.52, P < 0.010). Moreover, ROC curves showed that EZH2 expression predicted 1-year survival with an AUC of 0.740, 2-year survival with an AUC of 0.756, and 3-year survival with an AUC of 0.692, suggesting a robust predictive effect of EZH2 expression on prognosis. KEGG pathway analysis indicated five pathways showing the strongest positive correlation with EZH2 expression: cell cycle, DNA replication, Cell adhesion molecules cams, Primary immuno deficiency, Tsate transduction, and five pathways showing the strongest negative correlation with EZH2 expression: Glycolysis gluconeogenesis, Drug metabolism, cytochrome P450, retinol metabolism, fatty acid metabolism ribosome. We investigated the correlation between EZH2 expression and the level of immune infiltration in mesothelioma tissues. The results indicated that EZH2 expression played a critical role in immune infiltration, of which the high expression was correlated with the reduced number of NK cells, Mast cells, and Th17 cells. Moreover, mesothelioma patients with high EZH2 expression differ from those with low EZH2 expression in their tumor immune microenvironment. EZH2, as a new prognostic biomarker for mesothelioma, contributes to elucidating how changes in the immune environment promote the development of mesothelioma. Further analysis, EZH2 may serve as a biological test to predict the prognosis of mesothelioma.

Identification of EZH2 as Cancer Stem Cell Marker in Clear Cell Renal Cell Carcinoma and the Anti-Tumor Effect of Epigallocatechin-3-Gallate (EGCG).

Simple SummaryCancer stem cells (CSCs) refer to a group of undifferentiated heterogeneous tumor cells, defined as capable of self-renewal, differentiation, and may be linked to therapeutic resistance and tumor relapse. The development of novel therapeutic strategies to target CSCs and the identification of typical CSC markers are essential to improve therapy efficacy and prevent tumor relapse. Our study identifies CSC markers in renal cell carcinoma (RCC) and explores a potential treatment strategy and the underlying pharmacological mechanisms.The aim of the study was to develop a new therapeutic strategy to target cancer stem cells (CSCs) in clear cell renal cell carcinoma (ccRCC) and to identify typical CSC markers to improve therapy effectiveness. It was found that the corrected-mRNA expression-based stemness index was upregulated in kidney renal clear cell carcinoma (KIRC) tissues compared to non-tumor tissue and increased with higher tumor stage and grade. EZH2 was identified as a CSC marker and prognosis factor for KIRC patients. The expression of EZH2 was associated with several activated tumor-infiltrating immune cells. High expression of EZH2 was enriched in immune-related pathways, low expression was related to several metabolic pathways. Epigallocatechin-3-gallate (EGCG) was identified as the most potent suppressor of EZH2, was able to inhibit viability, migration, and invasion, and to increase the apoptosis rate of ccRCC CSCs. KIF11, VEGF, and MMP2 were identified as predictive EGCG target genes, suggesting a potential mechanism of how EZH2 might regulate invasiveness and migration. The percentages of FoxP3+ Treg cells in the peripheral blood mononuclear cells of ccRCC patients decreased significantly when cultured with spheres pretreated with EGCG plus sunitinib compared to spheres without treatment. Our findings provide new insights into the treatment options of ccRCC based on targeting CSCs.

Identification of a Necroptosis-Related Prognostic Signature and Associated Regulatory Axis in Liver Hepatocellular Carcinoma.

Background Liver hepatocellular carcinoma (LIHC) ranks the sixth in global cancer incidence with poor prognosis. Necroptosis is a kind of regulated cell death and has been proved to be of significance in cancer occurrence and progression. However, few studies comprehensively discuss the potential applications of necroptosis-related genes (NRGs) in the prognostic evaluation and immunotherapy of LIHC. Methods The prognostic signature in the present study was built up using LASSO Cox regression analysis. Integrated bioinformatics tools were utilized to explore the potential mRNA-miRNA-lncRNA regulatory axis in LIHC. Furthermore, qRT-PCR method was used to verify the EZH2 expression in LIHC tissues. Furthermore, prognostic performance of EZH2 in LIHC was assessed by Kaplan-Meier method. Results A total of 14 NRGs were differentially expressed in LIHC tissues. The overall genetic mutation status of these NRGs in LIHC was also shown. NRGs were significantly correlated with programmed necrotic cell death, as well as Toll-like receptor signaling pathway in GO and KEGG pathway analysis. Kaplan-Meier analysis revealed that ALDH2, EZH2, NDRG2, PGAM5, RIPK1, and TRAF2 were related to the prognosis. A prognostic signature was constructed by these six genes and showed medium to high accuracy in the prediction of LIHC patients' prognosis. Further analysis revealed that NRGs were correlated with pathological stage, immune infiltration, and drug resistance in LIHC. Moreover, we identified a potential lncRNA TUG1/miR-26b-5p/EZH2 regulatory axis in LIHC, which might affect the progression of LIHC. qRT-PCR suggested a higher mRNA level of EZH2 in LIHC tissues. And a poor overall survival rate was detected in LIHC patients with high EZH2 expression. Moreover, EZH2 expression and cancer stage were identified as the independent risk factors affecting LIHC patients' prognosis. Conclusion In the present study, we conducted comprehensive bioinformatic analyses and built up a necroptosis-related prognostic signature containing four genes (ALDH2, EZH2, NDRG2, and PGAM5) for patients with LIHC, and this prognostic signature showed a medium to high predictive accuracy. And our study also identified a lncRNA TUG1/miR-26b-5p/EZH2 regulatory axis, which might be of great significance in LIHC progression. In addition, based on the data from our center, the result of qRT-PCR and survival analysis showed a higher mRNA level of EZH2 in LIHC tissues and an unfavorable prognosis in high EZH2 expression group, respectively.

Integrated bioinformatics analysis reveals that EZH2-rich domains promote transcriptional repression in cervical cancer.

Cervical cancer is the third female cancer most common worldwide. The carcinogenic process involves an alteration of the mechanisms associated with transcription. Several studies have reported an oncogenic role of the polycomb complex subunit, EZH2. However, the role of EZH2 in cervical cancer is unknown. Hence, the objective of this study was to determine the role of EZH2 in transcriptional regulation in cervical cancer. The EZH2 expression and the methylation status of its promoter were analyzed in The Cancer Genome Atlas. The EZH2 enrichment profile was analyzed using chromatin immunoprecipitation with massively parallel DNA sequencing data provided by ENCODE project. The chromatin compartments were identified in the 4D Nucleome Data Portal. The functional annotation was examined in Enrichr. We report that EZH2 expression is increased in cervical cancer which is associated with hypomethylation of its promoter. EZH2 is enriched at promoter and distal intergenic regions. We identified that EZH2 defines chromatin domains enriched with H3K27me3 within repressive compartments in the HeLa-S3 cell line. Additionally, high EZH2 expression is associated with the repression of the senescent phenotype in cervical cancer patients. Our results suggest the participation of EZH2 in the generation of domains with a silencer function in cervical cancer, which regulate the expression of genes associated with cellular senescence.