Search Results (95)

Epigenetic dysregulation is a hallmark of glioblastoma (GBM) pathogenesis, with histone methylation playing a central role in chromatin remodeling and gene expression regulation. Enhancer of zeste homolog 2 (EZH2) is a key epigenetic regulator responsible for histone methylation. It primarily functions as a transcriptional repressor and regulates signaling pathways associated with tumor progression. Importantly, EZH2 is frequently recruited to long non-coding RNA (lncRNA) scaffolds, including HOTAIR and AGAP2-AS1, thereby enabling coordinated gene silencing by establishing repressive chromatin states. Although EZH2 expression is not consistently associated with overall survival in GBM, EZH2 remains a promising therapeutic target due to its roles in stemness and treatment resistance. This review summarizes current knowledge of EZH2 functions in normal and GBM cells, highlighting its complex functions and therapeutic potential. We also discuss the current status and limitations of EZH2-targeting therapies, including challenges related to blood–brain barrier penetration and clinical translation. Although a combination of EZH2 inhibitors and other epigenetic inhibitors may be beneficial in selected molecular contexts, its rationale depends on the underlying regulatory network. Future therapeutic development will require biomarker-driven patient stratification and precision medicine approaches to maximize clinical benefit in GBM. Full article

Background: Lung cancer remains the leading cause of cancer-related mortality, with non-small cell lung cancer (NSCLC) accounting for approximately 85% of cases. Over the past decade, immune checkpoint inhibitors have become a core component of first-line treatment for advanced-stage NSCLC lacking driver mutations. Programmed death-ligand 1 (PD-L1) expression is currently used as the standard biomarker, yet its predictive value remains limited, and in most immunotherapy trials, treatment efficacy has been observed independently of PD-L1 expression status. Enhancer of zeste homolog 2 (EZH2), an epigenetic regulator, promotes immune escape by suppressing antigen presentation and impairing CD8+ T-cell function, thereby generating an immune-cold tumor microenvironment, positioning it as a promising candidate biomarker. Methods: We retrospectively analyzed 102 NSCLC patients treated with immunotherapy at a single center between 2018 and 2024. EZH2 expression was assessed by immunohistochemistry. A cohort-derived 25% threshold was used for the primary exploratory analysis, and the analyses were repeated using a 50% threshold as a sensitivity analysis. Patients were classified as EZH2-high (45.1%) and EZH2-low (54.9%) at the 25% threshold. Results: At the 25% threshold, objective response rate (ORR) was 53.6% in the EZH2-low group and 45.7% in the EZH2-high group (Fisher’s exact p = 0.551), while disease control rate (DCR) was 64.3% and 60.9%, respectively (p = 0.837). Median overall survival (OS) was 37 versus 27 months (log-rank p = 0.323), and median progression-free survival (PFS) was 15 versus 12 months (p = 0.387). No significant correlation was found between EZH2 and PD-L1 expression (r = 0.167, p = 0.138). In treatment-line-adjusted Cox models, EZH2 expression was not associated with OS (hazard ratio (HR) 0.953, 95% confidence interval (CI) 0.533–1.704; p = 0.870) or PFS (HR 0.996, 95% CI 0.573–1.733; p = 0.989), whereas squamous histology was an independent predictor of survival. Results remained non-significant at the 50% threshold. Early progression was uncommon and did not differ significantly by EZH2 status overall or within PD-L1 strata. Conclusions: In this real-world cohort, EZH2 expression was not independently associated with response, early progression, OS, or PFS, and showed no correlation with PD-L1. These exploratory findings do not support the clinical use of EZH2 as a biomarker at this stage; prospective, multicenter studies using predefined thresholds and standardized immunohistochemical methods are needed to clarify its potential role as a marker complementary to PD-L1. Full article

Background: PRMT5, or protein arginine methyltransferase 5, is recognized as an epigenetic regulator that suppresses gene transcription through symmetric dimethylation of histone arginine residues, including histone H4 arginine 3 (H4R3me2s) and histone H3 arginine 8 (H3R8me2s), modifications associated with chromatin condensation and transcriptional repression. PRMT5-mediated methylation has been associated with recruitment of polycomb repressive complex 2 (PRC2) and enhancer of zeste homolog 2 (EZH2)-mediated H3K27me3 deposition, contributing to stable repression of tumor suppressor genes and apoptosis-related effectors in breast cancer. Methods: The molecular and functional impacts of PRMT5 inhibition were studied in TNBC cell lines with a pharmacological inhibitor (CMP5). Cellular responses were evaluated using a viability assay, qPCR, Western blotting, Annexin V/PI staining, and transwell migration/proliferation assays. Results: PRMT5 inhibition substantially reduced TNBC viability in a time- and dose-dependent manner. EZH2 was downregulated, whereas the tumor suppressor retinoblastoma-like protein 2 (RBL2) was induced, concomitant with low expression of Cyclin D1. These changes were accompanied by upregulation of pro-apoptotic effectors (Caspase-3, Caspase-10, death-associated protein 1 (DAP1), and BCL2-associated x protein (BAX) and repression of the pro-survival B-cell lymphoma 2 (BCL2), consistent with apoptosis-associated molecular responses. Functionally, CMP5 treatment was associated with reduced migratory behavior in TNBC cells under the experimental conditions tested. Conclusions: These findings suggest that PRMT5 inhibition by CMP5 is associated with reduced TNBC cell viability, impaired migration, increased expression of apoptosis-associated regulators and enhanced apoptotic cell death as measured by Annexin V/PI analysis in vitro. Further mechanistic and in vivo studies are required to clarify the therapeutic relevance of PRMT5 inhibition in TNBC. Full article

Enhancer of zeste homolog 2 (EZH2), the catalytic component of the polycomb repressive complex 2, is frequently overexpressed in lung adenocarcinoma and contributes to transcriptional programs that support tumor proliferation and cellular plasticity. However, its role in regulating senescence-associated signaling and tumor–stromal interactions in lung cancer remains incompletely understood. In this study, we combined transcriptomic analysis of The Cancer Genome Atlas lung adenocarcinoma cohort with functional characterization of EZH2 targeting in A549 cells using the catalytic inhibitor EPZ6438 and the EZH2 degrader MS1943. Elevated EZH2 expression was associated with enrichment of cell cycle-related transcriptional pathways. Pharmacological targeting of EZH2 reduced proliferation, migration, stemness-associated features, and sphere-forming capacity, with more pronounced effects observed following EZH2 degradation. Both compounds promoted features consistent with senescence-associated phenotypic remodeling characterized by increased expression of p16 and p21, enhanced β-galactosidase activity, G0/G1 cell cycle arrest, and increased expression of cytokines commonly associated with senescence-related secretory signaling, including IL-6, CCL2, and CXCL8. Conditioned medium from treated tumor cells promoted activation of primary lung fibroblasts, indicating functional paracrine microenvironmental remodeling. Importantly, EZH2 targeting elicited cytostatic responses without induction of apoptosis. Collectively, these findings suggest that EZH2 contributes to regulation of proliferation-associated and senescence-associated phenotypic programs together with stromal signaling in lung adenocarcinoma. Full article

Background/Objectives: Triple-negative breast cancer (TNBC) is a candidate for immune checkpoint blockade; however, current biomarkers remain insufficient to predict therapeutic response or capture tumor-intrinsic mechanisms. Enhancer of Zeste Homolog 2 (EZH2)-mediated epigenetic repression has been implicated in immune evasion, yet the contribution of EZH2-repressed genes to anti-tumor immunity and clinical outcomes in TNBC remains unclear. We aimed to identify EZH2-associated epigenetically repressed genes in TNBC and evaluate their relevance as tumor-intrinsic regulators and potential predictors of immunotherapy outcome. Methods: We performed integrative in silico analyses of The Cancer Genome Atlas (TCGA) breast cancer cohorts to identify EZH2-associated hypermethylated genes in TNBC. A composite 30-gene signature (30GS) was defined based on transcriptional repression and promoter hypermethylation. Associations with clinical outcomes, tumor- and immune-related programs, and therapeutic response were evaluated, with validation in the I-SPY2 cohort and an independent TNBC patient cohort. Results: The 30GS was significantly reduced in TNBC and basal-like tumors and associated with improved clinical outcomes and enrichment of tumor- and immune-related signatures. In the I-SPY2 cohort, the 30GS predicted pathological complete response in patients receiving chemo-immunotherapy (AUC = 0.7377, p = 0.0007). Gene-level analysis identified Dual Specificity Phosphatase 5 (DUSP5) as the gene most consistently associated with immune-related parameters. In an independent TNBC cohort, DUSP5-high tumors demonstrated transcriptional programs enriched for inflammatory, immune-related, and signaling pathways within the NanoString Breast Cancer 360 panel. Conclusions: This study defines an EZH2-associated epigenetic program linked to tumor-intrinsic immune programs in TNBC and identifies DUSP5 as a candidate gene associated with immune-related transcriptional states. Full article

Hepatocellular carcinoma (HCC) is a highly aggressive malignancy with poor prognosis and limited therapeutic options. Although epigenetic dysregulation is a hallmark of HCC, rational combinatorial targeting strategies remain incompletely defined. Here, we identify cooperative oncogenic functions of the chromatin modifiers enhancer of zeste homolog 2 (EZH2) and lysine-specific demethylase 1 (LSD1) in HCC. Analysis of the TCGA-LIHC cohort revealed that co-elevated EZH2 and LSD1 expressions are significantly associated with reduced overall survival. Gene set enrichment analysis demonstrated enrichment of Sonic Hedgehog (SHH) signaling and stress-responsive transcriptional programs in tumors with high EZH2/LSD1 expression. Functionally, dual pharmacological inhibition of EZH2 (GSK126) and LSD1 (SP2509) suppressed HCC cell proliferation, induced G1-phase arrest, and enhanced apoptosis, as evidenced by increased caspase-3/7 activity and decreased pro-caspase levels. Dual inhibition also impaired migration, invasion, tumor sphere formation, and stemness-associated gene expression. Mechanistically, co-targeting disrupted SHH signaling through the suppression of GLI1 expression. Chromatin immunoprecipitation revealed reduced EZH2, LSD1, and STAT3 occupancy at the GLI1 promoter following dual inhibition, leading to the repression of GLI1 and its downstream targets. Collectively, these findings demonstrate that EZH2 and LSD1 cooperatively sustain GLI1-dependent SHH signaling in HCC, and that dual epigenetic inhibition represents a mechanistically defined therapeutic strategy. Full article

Neuroblastoma (NB) represents a paradigmatic developmental malignancy in which lineage specification, oncogenic signalling, and epigenetic regulation converge to define tumour behaviour. Among the molecular axes shaping NB heterogeneity, neurotrophin receptors of the tropomyosin receptor kinase (Trk) family (TrkA, TrkB, and TrkC) and the p75NTR occupy a central position at the intersection between neuronal differentiation programs and malignant plasticity. While high TrkA and TrkC expression is associated with adrenergic identity, differentiation competence, and favourable clinical outcome, TrkB, frequently sustained by BDNF-driven autocrine loops, characterises mesenchymal-like, therapy-resistant states enriched in metabolic and inflammatory adaptations. Importantly, in NB, the dysregulation of neurotrophin signalling rarely arises from recurrent genetic alterations of neurotrophic tyrosine receptor kinase (NTRK) loci. Instead, Trk receptor expression is dynamically shaped by promoter methylation, polycomb repressive complex 2/Enhancer of Zeste homolog 2 (PRC2/EZH2)-dependent chromatin repression, MYCN-driven transcriptional silencing, enhancer rewiring, and microRNA-mediated control. These epigenetic mechanisms govern reversible transitions along the adrenergic–mesenchymal (ADRN–MES) continuum, enabling tumour cells to adapt to microenvironmental and therapeutic stress. Single-cell and spatial multi-omics approaches have further revealed that Trk-associated phenotypes are embedded within complex regulatory circuits integrating receptor tyrosine kinase (RTK) networks, cytokine signalling, metabolic remodelling, and stromal reinforcement. Here, we provide a comprehensive synthesis of the epigenetic and microenvironmental mechanisms regulating neurotrophin receptors in NB, with particular emphasis on how chromatin plasticity and cell-state transitions reshape Trk-dependent signalling outputs. We discuss advanced three-dimensional and organoid-based models that recapitulate niche-specific regulation of the Trk axis and evaluate emerging therapeutic strategies combining epigenetic modulators, differentiation-inducing agents, and RTK-targeted compounds. Understanding the temporal and spatial dynamics of Trk signalling may open new opportunities to therapeutically stabilise differentiation states and disrupt adaptive resistance programs in high-risk NB. Full article

Enhancer of Zeste Homolog 2 (EZH2), the catalytic subunit of Polycomb Repressive Complex 2 (PRC2), mediates histone H3 lysine 27 trimethylation (H3K27me3), an epigenetic modification associated with transcriptional repression. EZH2 inhibitors (EZH2is) gained attention after the first-in-class drug Tazemetostat received FDA approval for treating epithelioid sarcoma. Preclinical studies suggest that EZH2is could be effective against melanoma, but their general inability to cross the blood–brain barrier (BBB), among others, limits the treatment of secondary brain metastases. Based on these limitations, we designed SG-8, a novel compound derived from TDI-6118 (a known brain-penetrant EZH2i). In silico docking predicted that SG-8 may exhibit high affinity for EZH2 as well as for another PRC2 subunit, Embryonic Ectoderm Development (EED). In addition, in vitro PAMPA assays suggested passive BBB permeability of SG-8. In cell-based assays, SG-8 and the structurally related EZH2i PF-06726304 displayed lower cytotoxicity than Tazemetostat in both primary (A375) and metastatic (Colo-679) human melanoma cells. Western blot analysis showed that SG-8 and PF-06726304 markedly reduced EED protein levels and, to a lesser extent, EZH2 levels, without affecting total H3K27me3, consistent with preserved canonical PRC2 activity. Instead, treatment with both compounds—most prominently SG-8—was associated with reduced phosphorylation levels of EZH2 (Ser21) and its upstream regulator Akt (Ser473), suggesting that modulation of the Akt–EZH2 signaling axis may at least partially contribute to their anti-melanoma activity. Full article

Enhancer of zeste homologs inhibitory protein (EZHIP) is a eutherian-specific protein, with poorly defined developmental functions and physiological expression restricted to germ cells. Its aberrant re-expression characterizes posterior fossa ependymoma subtype A and a subset of diffuse midline gliomas with wild-type histone H3—aggressive pediatric brain tumors marked by global loss of the repressive H3 lysine 27 trimethylation (H3K27me3). Functionally analogous to the H3 lysine 27 to methionine (H3K27M) oncohistone, EZHIP inhibits Polycomb repressive complex 2 (PRC2), altering genome-wide H3K27me3 distribution and fate commitment. Unlike H3K27M, EZHIP is epigenetically silenced under physiological conditions yet inducible, suggesting context-dependent oncogenic roles. Its intrinsically disordered structure enables multifunctional interactions and biological versatility. Beyond brain tumors, EZHIP has emerged as an oncogenic driver in osteosarcoma, underscoring broader relevance across cancers. This review integrates current insights into EZHIP—from gene discovery and the mechanism of PRC2 inhibition to its emerging roles in metabolism, DNA repair, 3D chromatin regulation, and development. We outline EZHIP’s clinico-pathological significance in pediatric and adult malignancies, with an emphasis on EZHIP-driven hindbrain tumors. Finally, we discuss therapeutic opportunities, from the direct targeting of intrinsically disordered proteins to the indirect modulation of EZHIP-associated epigenetic and metabolic landscapes, highlighting implications for tumor evolution and precision oncology. Full article

High-risk human papillomavirus (HPV) is a crucial risk factor in the development of cervical cancer, where epigenetic modifications and epithelial–mesenchymal transition (EMT) processes have been implicated in cancer progression and metastasis. Enhancer of zeste homolog 2 (EZH2), a histone methyltransferase, is frequently overexpressed in HPV-associated cervical cancers and has been linked to tumour progression. However, there is still no consensus on the mechanisms of their action and their effectiveness on HPV-associated cancers. This study aimed to investigate whether EZH2 inhibitors (EPZ6438 and ZLD1039) can be effective in managing cervical cancer with less toxic effects than the conventional chemotherapeutic drug cisplatin. Proliferation assay and flow cytometry results showed that EZH2 inhibitors effectively induced apoptosis and arrested cells in G0/G1 phase in both HPV+ and HPV- cervical cancer cells. Both inhibitors downregulated the expression of EZH2 and HPV16 E6/E7 at mRNA and protein levels whilst upregulating expressions of p53 and Rb and epithelial markers. In summary, both EZH2 inhibitors showed therapeutic potential in comparison to cisplatin based on cellular and molecular readouts. Additionally, EPZ6438 showed a greater efficacy and higher sensitivity towards HPV+ cells, which was further supported by preliminary in vivo results from the chorioallantoic membrane assay. Full article

The accumulation of advanced glycation end products (AGEs) is a hallmark of prolonged high glucose levels in diabetes mellitus. We have previously reported that hypoxia and AGEs cause epigenetic modification of the repressive mark H3K27me3 in podocytes by downregulation of enhancer of zeste homolog 2 (EZH2) and nuclear inhibitor of protein phosphatase 1 (NIPP1). However, their impact on proximal tubular cells remains unclear. The aim of this study was to investigate the role of AGEs and diabetes on the epigenetic modifications of EZH2 and H3K27me3 in proximal tubular cells and in diabetic (db/db) mice. Our results show that AGEs reduced EZH2 expression in TKPTS cells, thereby decreasing the tri-methylation of H3K27. qRT-PCR analysis revealed upregulation of genes known to contribute to diabetic nephropathy and kidney injury as Ctgf, Snai1, and p27^Kip1. Consistently, immunofluorescent staining of renal sections from db/db mice confirmed the reduction in H3K27me3 levels in proximal tubules compared to non-diabetic controls. In summary, we show that AGEs induce epigenetic changes in proximal tubular cells by suppressing EZH2, thereby facilitating the transcription of genes involved in progression of diabetic nephropathy. These results provide new insights into metabolic memory, a process in which prior poor glucose control triggers ongoing renal damage despite current normoglycemia. Full article

Background: Cervical cancer remains a major global health burden, and treatment failure due to radioresistance and secondary drug resistance severely limits clinical outcomes. Enhancer of zeste homolog 2 (EZH2) is a key epigenetic regulator implicated in tumor progression. This study aimed to determine whether EZH2-mediated PTEN silencing drives afatinib resistance via AKT activation in radiation-resistant cervical cancer cells. Methods: A radioresistant cervical cancer cell line (HeLaR) was established following cumulative irradiation (70 Gy). Cell viability, clonogenic survival, methylation-specific PCR (MSP), chromatin immunoprecipitation (ChIP), and Western blot analyses were conducted. EZH2 (Dznep; tazemetostat), PI3K, and AKT inhibitors were tested in combination with afatinib. A xenograft mouse model was used for in vivo validation. Results: HeLaR cells exhibited upregulation of EZH2 and H3K27me3, downregulation of PTEN, and sustained AKT activation. EZH2 inhibition restored PTEN expression, attenuated AKT phosphorylation, and re-sensitized cells to afatinib. MSP and ChIP confirmed EZH2-mediated PTEN promoter silencing. PI3K inhibition reproduced these effects, whereas ERK inhibition had minimal impact. In xenograft models, combined treatment with Dznep and afatinib significantly suppressed tumor growth compared to single agents. Conclusions: EZH2-driven PTEN suppression promotes AKT-dependent afatinib resistance in radiation-resistant cervical cancer. Targeting the EZH2–PTEN–AKT axis may provide a potential therapeutic approach to mitigate combined radioresistance and chemoresistance in recurrent cervical cancer, although further preclinical and clinical validation is required. Full article

Enhancer of Zeste Homolog 2 (EZH2) is a key epigenetic regulator known for its role in global gene silencing and is involved in a variety of cellular processes, including cell survival, proliferation, invasion, and self-renewal. As a core component of the Polycomb Repressive Complex 2 (PRC2), EZH2 catalyzes the trimethylation of histone H3 at lysine 27 (H3K27me3), leading to chromatin compaction and transcriptional repression. Dysregulated EZH2 expression is observed in a wide range of solid tumors and hematological malignancies and is frequently associated with increased metastatic potential and poor clinical outcomes. While EZH2 primarily mediates gene silencing through its canonical PRC2-dependent activity, it also exerts oncogenic effects via non-canonical mechanisms. In its non-canonical role, EZH2 acts independently of PRC2, interacting with other signaling molecules as a transcriptional activator or co-activator, thereby promoting the activation of oncogenic pathways. Through both canonical and non-canonical mechanisms, EZH2 significantly contributes to tumor initiation and its subsequent progression. Given its critical role in oncogenesis and cancer progression, EZH2 is under investigation as a potential biomarker for cancer diagnosis and prognosis. This review provides a comprehensive overview of EZH2’s function and oncogenic roles across human cancers. Enhanced insight into EZH2’s complex regulatory network may facilitate the development of more effective strategies to manage EZH2-driven malignancies. Full article

Prolonged breastfeeding (BF), as opposed to artificial infant formula feeding (FF), has been shown to prevent the development of obesity later in life. The aim of our narrative review is to investigate the missing molecular link between postnatal protein overfeeding—often referred to as the “early protein hypothesis”—and the subsequent transcriptional and epigenetic changes that accelerate the expansion of adipocyte stem cells (ASCs) in the adipose vascular niche during postnatal white adipose tissue (WAT) development. To achieve this, we conducted a search on the Web of Science, Google Scholar, and PubMed databases from 2000 to 2025 and reviewed 750 papers. Our findings revealed that the overactivation of mechanistic target of rapamycin complex 1 (mTORC1) and S6 kinase 1 (S6K1), which inhibits wingless (Wnt) signaling due to protein overfeeding, serves as the primary pathway promoting ASC commitment and increasing preadipocyte numbers. Moreover, excessive protein intake, combined with the upregulation of the fat mass and obesity-associated gene (FTO) and a deficiency of breast milk-derived microRNAs from lactation, disrupts the proper regulation of FTO and Wnt pathway components. This disruption enhances ASC expansion in WAT while inhibiting brown adipose tissue development. While BF has been shown to have protective effects against obesity, the postnatal transcriptional and epigenetic changes induced by excessive protein intake from FF may predispose infants to early and excessive ASC commitment in WAT, thereby increasing the risk of obesity later in life. Full article

Background: Inhibitors of cyclin-dependent kinases (CDKs) and epigenetic modifier enhancer of zeste homolog 2 (EZH2) have emerged as promising options in the pharmacotherapy of malignant tumors. Recently, we demonstrated synergistic antitumor effects of the CDK4/6 inhibitor abemaciclib and the EZH2 inhibitors GSK126 or tazemetostat in patient-derived glioblastoma (GBM) models. Importantly, all three drugs are substrates of the two most important plasma membrane multidrug transporters ABCB1 and ABCG2, with abemaciclib and tazemetostat also being inhibitors of these proteins. Methods: To investigate whether increased intracellular accumulation of either of the two drugs used in combination could have contributed to corresponding synergisms, we developed a simple LC-MS/MS method for simultaneous detection of the three substances in cell culture lysates. The method was validated in accordance with the current International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) guideline M10 on bioanalytical method validation and study sample analysis. Results: All acceptance criteria were met. Subsequent analysis of intracellular drug concentrations confirmed increased cellular uptake of tazemetostat in the presence of abemaciclib in both GBM cell lines studied compared to single agent treatment. A comparable pattern was also observed for GSK126, but in only one of the two cell lines used. Conclusions: In conclusion, the observed synergistic antitumor effect could be partly due to increased intracellular accumulation, although this alone is certainly not sufficient to explain it. Overall, the developed method provides a valuable approach for characterizing interactions at the transport level and for predicting the efficiency of both anticancer substance classes in different cell lines. Full article