Search Results (127)

Cancer metastasis is the leading cause of cancer-related mortality, accounting for more than 90% of cancer deaths worldwide. However, the epigenetic mechanisms governing the metastatic cascade remain incompletely understood. Epigenetic reprogramming, including reversible changes in histone modifications, DNA methylation, chromatin remodeling, and non-coding RNA (ncRNA)-mediated regulation, enables tumor cells to acquire invasive, migratory, stem-like, and immune-evasive characteristics. During epithelial-to-mesenchymal transition (EMT), key epigenetic regulators such as histone deacetylases (HDACs), the Polycomb repressive complex 2 (PRC2) subunit EZH2, lysine-specific demethylase 1 (LSD1/KDM1A), and bromodomain and extraterminal (BET) proteins repress epithelial gene expression while activating mesenchymal transcriptional programs, promoting invasion and dissemination. At distant sites, epigenetic plasticity facilitates metastatic colonization through mesenchymal-to-epithelial transition (MET) and adaptive chromatin remodeling. Because these changes are reversible, they represent attractive therapeutic targets. HDAC, EZH2, LSD1/KDM1A, BET, and DNA methyltransferase (DNMT) inhibitors have shown promise in preclinical models of metastasis, with several advancing through clinical trials. Long non-coding RNAs, particularly HOTAIR, function as epigenetic scaffolds that reinforce metastatic programs, while reciprocal interactions between tumor cells and the tumor microenvironment (TME) drive epigenetic adaptations that promote immune evasion and metastatic progression. In addition, circulating tumor DNA (ctDNA) methylation signatures are emerging as minimally invasive biomarkers for assessing metastatic risk and monitoring treatment. This review summarizes current insights into the epigenetic regulation of cancer metastasis, evaluates emerging epigenetic therapies, and highlights translational opportunities to advance precision anti-metastatic strategies and improve patient outcomes. Full article

Methylation of proteins is a critical post-translational modification that regulates diverse cellular processes, including signal transduction, protein stability, and enzymatic activity. The methyltransferase enzymes that catalyse the addition of such methyl groups onto target molecules fall into a wide variety of categories and as such are classified into numerous families. Among them, the methyltransferase-like (METTL) family represents a unique cluster of enzymes with structural similarity to arginine methyltransferases. This family comprises 27 members, many of which methylate lysine residues on proteins, while others target various forms of RNA. Although discovered just over a decade ago, the protein-methylating METTLs remain incompletely characterised. Notably, most identified protein substrates are non-histone proteins, underscoring the distinctive functional roles of these enzymes. This review focuses exclusively on the protein-methylating METTL family members, summarising current knowledge of their structural features, enzymatic targets, sub-cellular localisation, and expression patterns. Their emerging relevance to disease, particularly cancer, is also highlighted, alongside areas where mechanistic understanding remains limited. By consolidating recent advances, this review aims to provide a comprehensive overview of protein-methylating METTLs in humans and to identify the critical knowledge gaps that will guide future research into their biological roles and therapeutic potential. Full article

(1) Background: KMT2A (alias MLL) is located at chromosome 11q23 and encodes histone methyltransferase 2A which activates target genes via chromatin methylation of histone H3 lysine K4. Mutations of KMT2A, including partial tandem duplication (PTD) and fusion with partner genes, are present in both lymphoid and myeloid acute leukemia. More than 100 various KMT2A fusion genes have been described, with only a minority represented by cell line models. (2) Methods: Cytogenetic and genomic copy number analyses, PCR, Western blot and RNA-sequencing were performed to characterize aberrations in acute myeloid leukemia (AML) cell line KOPM-88. Bioinformatic analysis of public AML patient data revealed differentially expressed genes. Functional analyses were performed by siRNA-mediated knockdown and live-cell imaging. (3) Results: The AML cell line KOPM-88 is derived from a boy at relapse and has been reported to carry t(X;11)(q24;q23), albeit with uncharacterized breakpoints. In KOPM-88 we identified fusion gene KMT2A::SEPTIN6 generated by this translocation, but excluded KMT2A-PTD. KMT2A::SEPTIN6 activated bone morphogenetic protein (BMP)-signalling and inhibited expression of HOXA7 and HOXA9. BMP signalling in turn activated cell proliferation and inhibited CDKN2B expression. (4) Conclusions: KOPM-88 contains fusion gene KMT2A::SEPTIN6, representing the only cell line model for this rare type of KMT2A rearrangement. KOPM-88 may serve to advance novel therapeutic treatments for KMT2A::SEPTIN6-positive AML. Full article

Despite advances in multimodal treatment, head and neck squamous cell carcinoma (HNSCC) remains a major clinical problem owing to its high recurrence rate and frequent development of treatment resistance. Abnormal histone modifications, particularly lysine methylation regulated by methyltransferases (KMTs) and demethylases (KDMs), have emerged as key drivers of HNSCC initiation, progression, and cellular plasticity. This review aims to comprehensively evaluate the role of selected KMTs and KDMs in HNSCC biology, with a focus on their contribution to resistance to immunotherapy, radiotherapy, and cytotoxic chemotherapy. We summarize and critically analyze preclinical and clinical studies investigating histone methylation dynamics in HNSCC, with particular emphasis on enzymes such as KMT2C/D, EZH2, NSD1/NSD2, SMYD3, G9a/EHMT2, LSD1, KDM2A/B, KDM3, KDM4, KDM5, KDM6, KDM7, and KDM8. Attention is given particularly to pharmacological approaches targeting these proteins: we discuss small-molecule inhibitors of EZH2, LSD1, KDM4/5/6, and other KMT/KDMs that are currently in preclinical development or in early clinical trials, and we highlight completed and ongoing studies testing EZH1/2 inhibitors and epigenetic combinations in patients with recurrent and metastatic HNSCC. The deregulation of specific KMTs and KDMs reshapes histone methylation at key residues, thereby controlling cell cycle progression, epithelial–mesenchymal transition (EMT), stem cell phenotypes, DNA damage responses, and multiple interactions with the immune system in HNSCC. Targeting disrupted histone methylation pathways may partially reverse the epigenetic reprogramming of HNSCC cells and represents a promising strategy to improve treatment efficacy in patients with advanced disease. We also summarize the preclinical evidence and the currently limited clinical data on targeting histone methylation dynamics in HNSCC and discuss their therapeutic implications. Full article

Background/Objectives: Glioblastoma remains the most aggressive and lethal form of brain cancer, with no effective cure to date. The molecular mechanisms sustaining its development and relentless proliferation are still not fully understood. SETMAR, a protein lysine methyltransferase involved in various DNA repair and chromatin processes, has been reported as dysregulated in several cancers, including glioblastoma. Interestingly, S-SETMAR, a shorter isoform of SETMAR, has been suggested to antagonize the oncogenic properties of the full-length protein. Here, we explored the cellular and molecular consequences of S-SETMAR overexpression in glioblastoma cells. Methods: We compared native glioblastoma cells (8MGBA) with a recombinant 8MGBA line stably over-expressing αS-SETMAR, a stable form of S-SETMAR, using complementary cellular and molecular approaches. Results: Overexpression of αS-SETMAR markedly prolonged the cell cycle duration (from 27 to 37 h), leading to a significant decrease in cell proliferation. Unexpectedly, αS-SETMAR triggered genomic alterations characterized by an increased DNA content and extensive chromosomal instability, including aneuploidy, chromoanasynthesis-like rearrangements, and tripolar mitoses. Moreover, αS-SETMAR-expressing cells displayed heightened sensitivity to stress conditions mimicking chemotherapy and radiotherapy, resulting in increased apoptosis. Conclusions: Our findings identify αS-SETMAR as a dual modulator of glioblastoma cell fate—simultaneously slowing proliferation and promoting chromosomal instability while enhancing vulnerability to genotoxic stress. These results suggest that αS-SETMAR could serve as both a prognostic marker and a potential therapeutic tool in glioblastoma management. Full article

The lysine methyltransferase SMYD5 is an important regulator of development and has been implicated in multiple malignancies, such as heart disease, lung and gastric cancers, breast and hepatocellular carcinomas, and inflammatory bowel disease. Further, SMYD5 has been linked to the mild hypothermia response, RNA translation, and HIV-1 transcription. SMYD5 is ubiquitously expressed in lymphocytes and the fetal brain, retina, heart, gut, liver, and reproductive organs. Mechanistically, SMYD5 methylates histone residues H3K36, H3K37, and H4K20, as well as non-histone targets such as the ribosomal protein RPL40 and the HIV-1 Tat protein. Here, we review the literature on SMYD5, focusing on its epigenetic functions and its roles in development, cancer, and other biological processes. Full article

Polycomb repressive complex 2 (PRC2) regulates the expression of pluripotency genes in embryonic stem cells (ESCs) and suppresses multiple genes associated with development, cell fate determination, and differentiation. Mouse embryonic stem cells (mESCs) derived from protein kinase C inhibition (PKCi) exhibit self-renewal and pluripotency comparable to those ESCs captured by the classical 2iL (CHIR99021, PD0325901, and leukemia inhibitory factor) system. However, the dynamic expression pattern of PRC2 in PKCi-mESCs and its role in regulating pluripotency remain unclear. This study demonstrated that the expression level of the enhancer of zeste 2 gene (Ezh2), of which protein is the catalytic subunit of PRC2 responsible for the trimethylation of lysine 27 on nucleosome histone H3 subunit (H3K27me3), is significantly higher in PKCi-mESCs than in 2iL-mESCs. EZH2 knockdown enhances the self-renewal capacity of PKCi-mESCs, as evidenced by a significant increase in the number of undifferentiated mESCs colonies. The effect of an EZH2 reduced expression is accompanied by the upregulation of specific core pluripotency gene Nanog, along with the general downregulation of differentiational genes representing the three germ layers. Conversely, EZH2 overexpression promotes a significant differentiation of PKCi-mESCs, resulting in the downregulation of pluripotency genes, including core pluripotency genes Nanog and Sox2, as well as naïve pluripotency genes Klf4, Fgf4, and Esrrb, while with a wide upregulation of three germ layer associated genes. Importantly, Cleavage Under Targets and Tagmentation (CUT&Tag) demonstrates that EZH2 directly controls H3K27me3 enrichment at the Nanog promoter near the transcription start site. Thus, EZH2, a core subunit of PRC2, exhibits the distinct regulatory functions orchestrating mESCs at a poised state between self-renewal and differentiation under PKC inhibition. EZH2 exerts histone H3 methyltransferase activity to regulate Nanog expression as one of its key targets, thereby modulating the transcriptional regulatory network that maintains pluripotency and lineage specification in mESCs. Full article

Maternal infection (MI) can increase the risk of neurodevelopmental and behavioural changes. This study examined MI-induced changes in motor coordination through the inflammatory-pathway-mediated epigenetic status of Reln. On gestational day (GD) 10, rats were assigned as (i) Control (Ctrl); (ii) Cronobacter sakazakii (CS) infection on GD-10 through recto-vaginal colonization; (iii) Negative Control (NC) [infected with C. sakazakii and treated with dimethyl sulfoxide (DMSO) 1 h before and 24 h after infection]; and (iv) C. sakazakii-infected rats treated with matrix metalloproteinase inhibitor (MMPI), 1 h before and 24 h after infection (CS + MMPI). Offspring were subjected to footprint analysis and the ladder rung walking test, which revealed that MI caused significant deficits in motor coordination. In addition, MI activated complement components—a disintegrin and metalloproteinase with thrombospondin motifs-1 (ADAMTS-1, C5a)—as well as proinflammatory cytokines such as interleukin-6 (IL-6) and matrix metalloproteinases (MMP-2, MMP-3, and MMP-9). Furthermore, the levels of DNA methyltransferase 3 alpha (DNMT3A), methyl-CpG-binding protein 2 (MeCP2), and histone H3 lysine 4 trimethylation (H3K4me3) were elevated in the CS and NC groups. Concurrently, the level of Reln promoter methylation increased; as a result, mRNA and protein, as well as postsynaptic density protein-95 (PSD-95), levels were decreased. Overall, the findings suggest that MI altered MMP-2/3/9 activity, H3K4me3, and the methylation of Reln, thereby affecting reelin, synaptic protein expression, and motor coordination in an experimental meningitis rat model. Full article

Background: Chromosomal rearrangements involving lysine methyltransferase 2A (KMT2A) define a genetically distinct subset of acute myeloid leukemia (AML) in 10% of cases in adult patients; the frequency of KMT2A-r is higher in pediatric AML. Translocations involving the KMT2A locus at chromosome 11q23 result in the formation of a chimeric oncogene partner, where the N-terminal part of KMT2A is fused to a variety of translocation partners. The leukemogenic activity of KMT2A-fusion partners is related to their capacity to hyperactivate the expression of HOX-A and MEIS1 target genes, which stimulate the proliferation of hematopoietic stem cells. The oncogenic activity of KMT2A fusion proteins requires the binding with Menin, and this interaction can be targeted pharmacologically by small molecules acting as potent and selective Menin inhibitors. Methods: A search of the literature showed a marked development of experimental studies exploring the molecular pathogenesis of AML with KMT2A-r and of clinical studies evaluating new induction intensive treatments and the development of a targeted therapy based on Menin inhibitors. Results and Conclusions: In the present review article, we summarize our current understanding of the biology of KMT2A-r in AML development and the recent consistent progress made in the treatment of KMT2A-r AML through new chemotherapy regimens and targeted therapy using Menin inhibitors. However, the prognosis of older KMT2A-r AML patients remains poor and could be improved by drug combination studies including Menin inhibitors. Many encouraging observations derived from ongoing clinical trials with Menin inhibitors need to be confirmed through randomized clinical trials. Full article

The conserved protein SetDB1 has been identified in various vertebrate and invertebrate groups. It plays key roles in vital processes such as germline and nervous system development, immune response, tumorigenesis, cell cycle progression, and others. SetDB1 is initially characterized as an enzyme that methylates lysine 9 on histone H3, leading to gene silencing, which is traditionally considered its primary function. However, SetDB1 also targets about a dozen nuclear, cytoplasmic, and membrane proteins as substrates. Moreover, some functions of SetDB1 do not require methyltransferase activity. Due to its SUMO-interacting motif, Tudor domain, and methyl-binding domains, SetDB1 interacts with a wide range of complexes that regulate protein stability and activity, signal transduction pathways, and chromatin spatial organization. In this review, we aim to expand the classical view of SetDB1 as solely a histone methyltransferase and to highlight the broader diversity of its functions. Full article

Background/Objectives. Prostate cancer (PCa) is among the leading causes of death from cancer in men. Frequent use of androgen receptor inhibitors induces PCa transdifferentiation, leading to poorly differentiated neuroendocrine PCa (NEPC). ROR2 is critical for NEPC pathogenesis by activating ASCL1, promoting lineage plasticity. Protein lysine methylation mediated by N-lysine methyltransferases SMYD2 and its downstream effector EZH2 upregulates the NEPC marker ASCL1 and enhances c-MET signaling, promoting PCa aggression. Epidemiological studies suggest a lower incidence of certain malignancies in Mediterranean populations due to their intake of an olive-phenolics-rich diet. Methods. Cell viability, gene knockdown, and immunoblotting were used for in vitro analyses. A nude mouse NEPC xenograft model evaluated the anti-tumor efficacy of purified and crude oleocanthal. Xenograft tumors were subjected to RNA-seq, qPCR, and Western blot analyses, with clinical validation performed using tissue microarrays. Results. A tissue microarray analysis showed that SMYD2 expression was significantly elevated in PCa tissues with higher IHS versus normal prostate tissue cores. The olive phenolic S–(–)–oleocanthal (OC) suppressed the de novo NEPC NCI-H660 cells proliferation. Male athymic nude mice xenografted with the NCI-H660-Luc cells were used to assess OC effects on de novo NEPC progression and recurrence. Male NSG mice transplanted with LuCaP 93 PDX tumor tissues generated a heterogeneous in vivo model used to assess OC effects against t-NEPC progression. Daily oral 10 mg/kg OC administration significantly suppressed the NCI-H660-Luc tumor progression and locoregional recurrence after primary tumor surgical excision. OC treatments effectively suppressed the progression of LuCaP 93 PDX tumors. OC-treated tumors revealed downregulation of ROR2, ASCL1, SMYD2, and EZH2, as well as activated c-MET levels versus the placebo control. RNA sequencing of the collected treated NEPC tumors showed that OC disrupted NEPC splicing, translation, growth factor signaling, and neuronal differentiation. Conclusions. This study’s findings validate OC as a novel lead entity for NEPC management by targeting the ROR2-ASCL1-SMYD2-EZH2-c-MET axis. Full article

Background: Patients with neurodevelopmental and neuromuscular disorders often show overlapping clinical phenotypes. Pathogenic variants in KMT5B, a histone lysine methyltransferase, have been linked to neurodevelopmental disorders, yet their effects on human skeletal muscle remain unexplored. We report on a patient with KMT5B-linked disease who presented to a neuromuscular specialty clinic with significant involvement of skeletal muscle, where a multi-omics approach established the genetic diagnosis and revealed neuromuscular findings relevant for diagnosis, care and rehabilitation. Methods: Whole-exome sequencing was performed from blood and data was analyzed using the RD-Connect Genome Phenome Analysis Platform. Histological analysis and proteomic profiling were performed on muscle tissue. Results: Whole-exome sequencing revealed a pathogenic heterozygous variant (c.554_557del, p.Tyr185Cysfs*27) in KMT5B. Histological examination revealed fiber-type grouping, angular fibers, increased fast-twitch fiber proportion, and lipid droplet accumulation, indicative of muscle denervation. Proteomic profiling identified 77 dysregulated proteins, including upregulation of sarcomeric proteins, mitochondrial and glycolytic enzymes, acute-phase and complement factors, and extracellular matrix components, reflecting structural remodeling, metabolic adaptation, and inflammatory activation. These findings align with the role types observed in Kmt5b mouse models, supporting a role of KMT5B in neuromuscular function. Conclusions: We present the first combined histological and proteomic analysis of quadriceps muscle from a patient carrying a pathogenic KMT5B variant with a neuromuscular phenotype. The convergence of histological and proteomic alterations suggests that KMT5B haploinsufficiency may be associated with fiber-type shifts, denervation, and metabolic stress in human skeletal muscle. Understanding these processes provides mechanistic insight into motor deficits and informs targeted therapeutic strategies, including physiotherapeutic interventions, and early compensatory measures. Full article

Histone H3 lysine 36 (H3K36) methylation, a pivotal epigenetic mark that ensures transcriptional fidelity and genomic integrity, plays an essential role in development and tumorigenesis. The nuclear receptor-binding SET domain (NSD) family of histone methyltransferases, comprising NSD1, NSD2, and NSD3, primarily catalyzes mono- and di-methylation of H3K36 (H3K36me1/2) and engages with chromatin-associated and transcriptional regulatory complexes in a context-dependent manner. Increasing evidence demonstrates that NSD family members have emerged as critical drivers in human cancers. Recurrent gene amplifications, point mutations, and oncogenic fusions of NSD family genes are frequently observed in both solid and hematologic cancers. Their dysregulation contributes to tumorigenesis, cancer cell proliferation and survival, and metastatic progression through both H3K36 methylation-dependent and -independent mechanisms. Pharmacological inhibition of NSD catalytic activity, as well as alternative approaches such as targeted protein degradation or disruption of cofactor interactions, are emerging as promising therapeutic strategies for cancer treatment. This review summarizes the structural features, molecular functions, and cancer-associated alterations and mechanisms of the NSD family and highlights recent advances in targeting these enzymes as potential epigenetic vulnerabilities in cancer. Full article

KMT2C (histone lysine N-methyltransferase 2C, also known as MML3, myeloid/lymphoid or mixed-lineage leukemia 3) is a causal gene for Kleefstra syndrome 2, a rare neurodevelopmental disorder. Recent human genetic studies have identified it as a high-risk gene for autism spectrum disorder (ASD), with 79% of patients harboring KMT2C variants having ASD. However, the causal link between KMT2C haploinsufficiency and ASD remains unclear. KMT2C/MLL3 encodes a histone methyltransferase, a core protein of the KMT2C/D COMPASS (complex proteins associated with Set1) complex, which plays fundamental roles in chromatin modification, occupancy, and gene expression. The expression of KMT2C/Kmt2c peaks during the developmental period in the human/mouse brain, which indicates the critical roles of KMT2C/Kmt2c in neurodevelopment. Here, we investigated the impact of germline Kmt2c haploinsufficiency on autism-like behavioral deficits in mice, which modeled humans carrying diverse KMT2C variants. Compared with Kmt2c^+/+ controls, Kmt2c haploinsufficiency mice had normal motor function without anxiety-like behaviors. Notably, Kmt2c haploinsufficiency mice exhibited autism-like social deficits and increased self-grooming in both males and females, which recapitulated the core phenotypes of ASD patients. Novel object recognition and spatial memory deficits were observed in male and female Kmt2c haploinsufficiency mice. This study reveals a causal link between Kmt2c haploinsufficiency and ASD-like behavioral deficits. These germline Kmt2c haploinsufficiency mice can be used for further studying the molecular mechanisms and developing therapeutic interventions for KMT2C haploinsufficiency-associated behavioral deficits. Full article

Post-translational modifications (PTMs) expand the structural diversity of proteins beyond the standard amino acids, influencing protein-protein interactions. Protein methylation, a prevalent PTM, involves the transfer of methyl groups from S-adenosylmethionine (SAM) to lysine and arginine residues. Arginine methylation is catalyzed by the Protein Arginine Methyltransferase (PRMT) family to yield mono- and dimethylarginine forms. PRMT1, the isozyme responsible for the majority of asymmetric dimethylation (ADMA) is implicated in various diseases, including cancer. Here, we report the synthesis and screening of a second-generation peptide library to identify novel PRMT1 substrates. The library, based on histone peptides, incorporated varying sequences of amino acids, facilitating substrate specificity studies. Screening identified 7 peptide sequences as exceptional PRMT1 substrates, which were confirmed by kinetic analysis. Consensus sequences revealed key recognition elements for PRMT1 catalysis, suggesting roles for small non-polar side chains and specific residues near the substrate arginine. Furthermore, we developed a peptide-based PRMT1 inhibitor by substituting the substrate arginine with a chloroacetamidine warhead. The inhibitor exhibited sub-micromolar inhibitory potency against PRMT1, surpassing previous peptide-based inhibitors. Our findings contribute to understanding PRMT1 substrate specificity and provide a scaffold for developing potent inhibitors targeting PRMT1 in diseases, including cancer. Full article