Epigenetic regulation of cancer progression by EZH2: from biological insights to therapeutic potential

Integrative multi-omics identifies AP-1 transcription factor as a targetable mediator of acquired osimertinib resistance in non-small cell lung cancer

Osimertinib, a third-generation EGFR tyrosine kinase inhibitor (EGFR-TKI), has dramatically transformed the treatment landscape for patients with EGFR-mutant NSCLC. However, the long-term success of this therapy is often compromised by the onset of acquired resistance, with non-genetic mechanisms increasingly recognized as pivotal contributors. Here, we exploit a multi-omics approach to profile genome-wide chromatin accessibility and transcriptional landscapes between drug sensitive and resistant EGFR-mutant cells. Our findings reveal a robust concordance between epigenetic regulome and transcriptomic changes that characterize the osimertinib resistant state. Through CRISPR-based functional genomics screen targeting epigenetic regulators and transcription factors, we uncover a critical regulatory network featuring key members of the NuRD and PRC2 complexes that mediate resistance. Most critically, our screen identifies FOSL1 and JUN, two subunits of the AP-1 transcription factor within this network, as the most significant hits. Mechanistically, we demonstrate that cis-regulatory elements exhibiting altered chromatin accessibility in the resistant state are enriched for cognate AP-1 binding motifs, enabling AP-1 to orchestrate a gene expression program that underpins the druggable MEK/ERK signaling axis, potentially enhancing cell viability and fitness of resistant cells. Importantly, genetic depletion or pharmacological inhibition of AP-1 reinstates cellular and molecular sensitivity, and reverts resistance-associated phenotypes, such as epithelial-to-mesenchymal transition, upon anti-EGFR rechallenge by repressing AKT and ERK signaling. These findings provide novel insights into the epigenetic and transcriptional control of osimertinib resistance in EGFR-mutant NSCLC, highlighting AP-1 as a targetable vulnerability of resistance-related hallmarks and offering a promising avenue for developing resistance reversal strategies.

Downregulation of EZH2 Promotes Renal Epithelial Cellular Senescence and Kidney Aging

Renal epithelial cell senescence and kidney aging have become the focus of scientific investigation. However, how epigenetic regulation in these processes remains elusive. Enhancer of zeste homolog 2 (EZH2), a histone methyltransferase, regulates trimethylation of histone H3 at lysine 27 (H3K27me3) and plays an important role in renal pathophysiology. In this study, we show that the expression of EZH2 is decreased in naturally aged and irradiation (IR)-induced mouse kidneys, as well as in IR-induced human renal cortical tubular epithelial (RCTE) cells through proteasome-mediated degradation. Inhibition of EZH2 with its specific inhibitor 3-DZNeP promotes tubular cell senescence and kidney aging characterized by an increase in the expression of senescence markers, including p16 and p21, in mouse kidneys and in IR-induced RCTE cells. We show that EZH2 represses the transcription of p16 through trimethylation of H3K27me3, which directly binds to the promoter of p16. EZH2 represses the transcription of p21 through directly binding to the promoter of p21, and this process is involved in its interaction with p53 and its phosphorylation by ataxia-telangiectasia mutated (ATM), a critical protein involved in the cellular response to DNA damage. Inhibition of ATM with its inhibitor decreased the phosphorylation of EZH2 and the binding of EZH2 to the promoter of p21 in IR-treated RCTE cells in a p53-dependent manner. This study suggests that EZH2 plays a critical role in preventing kidney aging and DNA-damage-induced renal tubular cellular senescence, in which senescence and kidney aging also result in the destabilization of EZH2, forming a negative feedback loop.

Effect of Cytochrome P450 3A Inhibition and Induction by Itraconazole and Rifampin on Tazemetostat Pharmacokinetics in Patients With Advanced Malignancies

This study (NCT04537715) investigated itraconazole (strong cytochrome P450 [CYP] 3A inhibitor) and rifampin (strong CYP3A inducer) on tazemetostat pharmacokinetics. In Part 1, patients received tazemetostat 400 mg orally on Days 1, 15, and 36, and 400 mg twice daily on Days 3-14 and Days 21-35. Itraconazole 200 mg orally once daily was administered on Days 18-38. In Part 2, patients received tazemetostat 800 mg orally once daily on Days 1, 15, and 24, and 800 mg twice daily on Days 3-14 and Days 17-23. Rifampin 600 mg orally once daily was administered on Days 17-25. Twenty-one patients in each part completed had plasma concentrations quantified for pharmacokinetic assessments. Itraconazole coadministration resulted in higher tazemetostat exposures after single doses (Day 21/Day 1) and steady state (Day 36/Day 15). Compared with tazemetostat alone, itraconazole increased mean maximum plasma concentration (Cmax) and area under the concentration-time curve from time 0 to 12 hours (AUC0-12h) by 2.00- and 3.12-fold, respectively, after single doses. Following twice-daily dosing, itraconazole increased mean steady-state Cmax and AUC0-12h by 1.86- and 2.47-fold, respectively. Rifampin coadministration decreased tazemetostat steady-state (Cmax) and AUC0-12h by approximately 84% (Day 24/Day 15). Itraconazole increased tazemetostat exposure by 2-3-fold, and rifampin decreased tazemetostat exposure by 84%, indicating that coadministration of tazemetostat with strong CYP3A inhibitors or inducers should be avoided.

Construction and Evaluation of a Prognostic Columnar Graphic Model for Adult Patients with Diffuse Midline Gliomas

OBJECTIVE

To explore the prognostic factors of adult patients with diffuse midline glioma (DMG), and to further construct and evaluate prognostic columnar graphic models to provide some reference for the clinical management of this group of patients.

METHODS

We included adult patients with histologically confirmed DMG from the SEER (Surveillance Epidemiology and End Results) database (2004-2015), dividing them into training and validation sets (7:3 ratio). Using Kaplan-Meier and Cox regression analyses, we determined independent prognostic factors for overall survival (OS) and cancer-specific survival (CSS). Prognostic column-line graphic models were developed for OS and CSS, incorporating patient demographics and clinical characteristics. The models underwent internal and external validation, with performance assessed using the Concordance Index, area under the curve values, and calibration plots.

RESULTS

The study encompassed 226 patients, showing age, tumor extension, and World Health Organization grades as significant prognostic factors. The constructed models for OS and CSS showed moderate reliability and predictive accuracy, with Concordance Index values of 0.786 (OS) and 0.79 (CSS) in the training set and 0.743 (OS) and 0.787 (CSS) in the validation set. Calibration plots and decision curve analysis confirmed the clinical usefulness of the models.

CONCLUSIONS

The column-line graphic prediction models for OS and CSS have moderately reliable predictive efficacy and help clinicians to better assess the prognosis and provide individualized treatment options for adults with DMG.

S-nitrosylation of EZH2 alters PRC2 assembly, methyltransferase activity, and EZH2 stability to maintain endothelial homeostasis

Nitric oxide (NO), a versatile bio-active molecule modulates cellular functions through diverse mechanisms including S-nitrosylation of proteins. Herein, we report S-nitrosylation of selected cysteine residues of EZH2 in endothelial cells, which interplays with its stability and functions. We detect a significant reduction in H3K27me3 upon S-nitrosylation of EZH2 as contributed by the early dissociation of SUZ12 from the PRC2. Moreover, S-nitrosylation of EZH2 causes its cytosolic translocation, ubiquitination, and degradation. Further analysis reveal S-nitrosylation of cysteine 329 induces EZH2 instability, whereas S-nitrosylation of cysteine 700 abrogates its catalytic activity. We further show that S-nitrosylation-dependent regulation of EZH2 maintains endothelial homeostasis in both physiological and pathological settings. Molecular dynamics simulation reveals the inability of SUZ12 to efficiently bind to the SAL domain of EZH2 upon S-nitrosylation. Taken together, our study reports S-nitrosylation-dependent regulation of EZH2 and its associated PRC2 complex, thereby influencing the epigenetics of endothelial homeostasis.

Immunoexpressions of PD-L1 and EZH2 in Endometrial Carcinoma: Associations with Clinicopathological Parameters

Background: This study investigated PD-L1 and EZH2 immunoexpressions in endometrial carcinomas (ECs) and correlated their associations with clinicopathological parameters and five-year survival outcomes. Methods: A cross-sectional, retrospective study was conducted on all ECs diagnosed between January 2014 and December 2018. Immunohistochemical staining for PD-L1 (clone 22C3) and EZH2 was performed on tumour samples, and their expression levels were assessed. Results: Among the 104 EC cases included, 19.2% (n = 20) overexpressed PD-L1, while 8.7% (n = 9) overexpressed EZH2. Most (n = 19/20, 95.0%) PD-L1-expressing tumour cells showed EZH2 immunonegativity. Likewise, most (n = 8/9, 88.9%) EZH2-expressing ECs were PD-L1-negative. Increased PD-L1 and EZH2 expressions in ECs were seen more frequently in women more than 60 years of age (p = 0.013 and p = 0.039). EZH2 overexpression was associated with higher tumour grade (p = 0.009) and more aggressive histological subtypes (p = 0.013), while PD-L1 expression was not significantly associated with tumour grade, tumour stage, histological subtypes, and lymph node status (p > 0.05). Kaplan-Meier survival analysis revealed that PD-L1-positive ECs had a significantly better five-year overall survival (OS) rate compared to PD-L1-negative ECs (p = 0.034). Conversely, EZH2 overexpression did not correlate with survival outcomes (p > 0.05). Notably, the combination of PD-L1 and EZH2 expression patterns on ECs (PD-L1-/EZH2+) portends the worst OS compared to other combined PD-L1/EZH2 expression patterns (p = 0.05). Conclusions: PD-L1 immunoexpression was associated with better survival outcomes in ECs, while overexpression of EZH2 was associated with higher tumour grade and aggressive histological subtypes, suggesting their potential utility as prognostic biomarkers in ECs.

Nonenzymatically modified mRNA for regulating translation and apoptosis by modulating Cancer epigenetics

In this study, we employed imidazole-activated natural or modified guanosine derivatives to extend the 3' ends of mRNA using a nonenzymatic method beyond 30 poly-A tails. We evaluated their impact on the translation activity in cell studies using three genes: GFP, Luciferase, and Apoptin. The assessments were conducted through cell imaging, fluorescence, luminescence, western blot analysis, and RT-qPCR to evaluate varying apoptosis-mediated EZH2 expression in cancer epigenetics, among the compounds tested GMP-2-amino-IM, 2'O-Me-2-amino-IM, and N7-(2-MePy)-GMP-IM. The sugar-modified 2'O-Me-GMP-2-amino-IM demonstrated the most favorable results as mRNAs treated with this compound exhibited higher expression levels with promising mRNA stability relative to the control mRNA (without any extension) and other tested compounds. Subsequently, we transfected cancer cells with nonenzymatically modified apoptin mRNAs by utilizing the three imidazole-activated guanosine derivatives compounds and monitored the induced apoptosis. These findings suggest that 2'O-Me-2-amino-IM-modified apoptin mRNA could serve as a promising tool for cancer therapy by inducing apoptosis while selectively modulating EZH2 expression, a key regulator in oncogene suppression.

Proteogenomic discovery of RB1-defective phenocopy in cancer predicts disease outcome, response to treatment, and therapeutic targets

Genomic defects caused by truncating mutations or deletions in the Retinoblastoma tumor suppressor gene (RB1) are frequently observed in many cancer types leading to dysregulation of the RB pathway. Here, we propose an integrative proteogenomic approach that predicts cancers with dysregulation in the RB pathway. A subset of these cancers, which we term as "RBness," lack RB1 genomic defects and yet phenocopy the transcriptional profile of RB1-defective cancers. We report RBness as a pan-cancer phenomenon, associated with patient outcome and chemotherapy response in multiple cancer types, and predictive of CDK4/6 inhibitor response in estrogen-positive breast cancer. Using RNA interference and a CRISPR-Cas9 screen in isogenic models, we find that RBness cancers also phenocopy synthetic lethal vulnerabilities of cells with RB1 genomic defects. In summary, our findings suggest that dysregulation of the RB pathway in cancers lacking RB1 genomic defects provides a molecular rationale for how these cancers could be treated.

Exosomal RNAs and EZH2: unraveling the molecular dialogue driving tumor progression

The EZH2 gene encodes an enzyme that is part of the epigenetic factor Polycomb Repressive Complex 2 (PRC2). In order to control gene expression, PRC2 mainly modifies chromatin structure. In this complex process, EZH2 methylates histone proteins, which in turn suppresses further RNA transcriptions. As a result, EZH2 dysregulations can occasionally induce abnormal gene expression patterns, which can aid in the development and progression of cancer. Non-coding RNAs significantly impact the expression of EZH2 through epigenetic mechanisms. Meanwhile, normal and cancerous cells frequently release vesicles into the extracellular matrix, also known as exosomes, that occasionally carry RNA molecules from their origin cells, including messenger RNAs, microRNAs, and other non-coding RNAs. Thus exosomes are granted the ability to regulate numerous physiological functions and act as crucial messengers between cells by influencing gene expression in the recipient cell. We conducted this review to focus on EZH2's substantial biological role and the mechanisms that regulate it, driven by the desire to understand the possible impact of exosomal RNAs on EZH2 expression.

EZH1/EZH2 inhibition enhances adoptive T cell immunotherapy against multiple cancer models

Tumor resistance to chimeric antigen receptor T cell (CAR-T) and, in general, to adoptive cell immunotherapies (ACTs) is a major challenge in the clinic. We hypothesized that inhibiting the tumor drivers' methyltransferases EZH2 and EZH1 could enhance ACT by rewiring cancer cells to a more immunogenic state. In human B cell lymphoma, EZH2 inhibition (tazemetostat) improved the efficacy of anti-CD19 CAR-T by enhancing activation, expansion, and tumor infiltration. Mechanistically, tazemetostat-treated tumors showed upregulation of genes related to adhesion, B cell activation, and inflammatory responses, and increased avidity to CAR-T. Furthermore, tazemetostat improved CAR- and TCR-engineered T cell efficacy in multiple liquid (myeloma and acute myeloid leukemia) and solid (sarcoma, ovarian, and prostate) cancers. Lastly, combined EZH1/EZH2 inhibition (valemetostat) further boosted CAR-T efficacy and expansion in multiple cancers. This study shows that EZH1/2 inhibition reprograms tumors to a more immunogenic state and potentiates ACT in preclinical models of both liquid and solid cancers.

Capsanthin inhibits migration and reduces N-linked glycosylation of PD-L1 via the EZH2-PD-L1 axis in triple-negative breast cancer brain metastasis

Breast cancer metastasis to the brain, occurring in about 15-25% of cases, represents a major obstacle in the treatment of triple-negative breast cancer (TNBC). The molecular mechanisms driving this form of metastasis are still largely unknown. PD-L1, an immune checkpoint protein, is central to tumor immune evasion and has become a focus for immunotherapy development. While PD-L1 inhibitors have shown success in various cancer types, their effectiveness in TNBC brain metastases remains to be fully investigated. This highlights the urgent need to understand the complex interactions between metastatic brain tumors and the tumor microenvironment in TNBC patients. Gaining insights into these dynamics is crucial for developing new targeted therapies, including those that modulate the PD-L1 pathway, to better manage and treat TNBC brain metastases. We explore the impact of Capsanthin on the tumor microenvironment of brain metastases in triple-negative breast cancer (TNBC). Our results reveal that Capsanthin effectively inhibits the migration of brain metastasis TNBC cells. Furthermore, Capsanthin significantly reduces the expression of EZH2 and N-linked glycosylated PD-L1 proteins and mRNA in TNBC cells, encompassing both primary and metastatic sites, as well as in mesenchymal stem cells (3A6). Data from The Cancer Genome Atlas (TCGA) indicate that elevated expression levels of EZH2 correlate with poorer patient prognosis. Immunoprecipitation assays demonstrate a direct interaction between EZH2 and PD-L1 in brain metastases of TNBC, underscoring the pivotal role of the EZH2-PD-L1 axis. Additionally, Capsanthin was found to suppress the expression of epithelial-mesenchymal transition (EMT) markers in metastatic brain TNBC cells and mesenchymal stem cells. Our results suggest that Capsanthin can modulate the tumor microenvironment and inhibit key pathways involved in cancer progression, offering potential therapeutic benefits for patients with TNBC brain metastases.

Non-genotoxic carcinogens (TPA and mezerein) activate tumourous transformation through miR let-7-mediated Hmga2 expression in Bhas42 cells

A Bhas42 cell transformation assay is a method used to detect the tumour-promoting activities of chemicals. However, the mechanisms underlying tumour transformations mediated by non-genotoxic carcinogens (NGCs) are poorly understood. This study aimed to examine the correlation between 12-O-tetradecanoylphorbol 13-acetate (TPA) or mezerein and the initiation of tumourous transformations by epigenetic regulation in Bhas42 cells. We found that TPA and mezerein prompted tumourous transformations by stimulating cell proliferation and migration in Bhas42 cells. Furthermore, we observed alterations in the expression levels of 134 genes, with 87 genes being upregulated and 47 genes being downregulated, following exposure to either TPA or mezerein. Among the differentially regulated genes, we identified 17 upregulated genes and 8 downregulated genes corresponding to differentially expressed genes in TNM [primary tumour (T), regional nodes (N), and metastasis (M)]. Importantly, we found that TPA and mezerein triggered the expression of Hmga2 and Ezh2 by loss of miRNA let-7 (miR let-7) in Bhas42 cells. Finally, the microRNA (miRNA) mimic of let-7 prevented the TPA- and mezerein-induced activation of Hmga2 and Ezh2 in Bhas42 cells. Our findings reveal a connection between tumourous transformations and the epigenetic regulator miR let-7 in NGCs, such as TPA and mezerein in Bhas42 cells. This highlights miR let-7 as a promising therapeutic target for mitigating tumourous transformations induced by NGCs.

Molecular basis of symptomatic sporadic primary hyperparathyroidism: New frontiers in pathogenesis

Primary hyperparathyroidism is a common endocrine disorder characterized by inappropriate elevation of parathyroid hormone and hypercalcemia. While predominantly an asymptomatic disease in Western populations, symptomatic presentations are more prevalent in Eastern countries. The molecular pathogenesis of sporadic PHPT primarily involves genetic and epigenetic alterations leading to abnormal parathyroid cell proliferation and altered calcium sensing mechanism. To date, MEN1 and cyclin D1 are the only established drivers of sporadic PHPT. Somatic MEN1 gene mutations occur in 30-40 % of sporadic parathyroid adenomas (PA), with a recent study on symptomatic cases reporting germline variants.Cyclin D1 overexpression in sporadic PA has been observed in 20-40 % of cases in Western populations and 80 % of cases in Eastern populations, with an inverse association with cyclin-dependent kinase inhibitors CDKN2A and CDKN2B expression. The calcium-sensing receptor expression was significantly lower in symptomatic compared to asymptomatic PHPT, strongly supported by epigenetic deregulation (promoter hypermethylation and histone methylation). Recent studies have highlighted the potential involvement of EZH2, a histone methyltransferase, in parathyroid tumorigenesis. Additionally, parathyroid-specific transcription factors like GCM2, PAX1, and GATA3 are emerging as putative tumor suppressors, especially from the symptomatic PHPT. Next-generation sequencing has identified novel potential drivers such as PIK3CA, MTOR, and NF1 in sporadic PC, alongside CDC73. The molecular landscape of sporadic PHPT appears to differ between Eastern and Western populations. This heterogeneity underscores the need for further large-scale studies, particularly in symptomatic cases from developing nations, to comprehensively elucidate the molecular drivers of parathyroid tumorigenesis.

Advances in epigenetic treatment of adult T-cell leukemia/lymphoma: a comprehensive review

Human T-cell lymphotropic virus type 1 (HTLV-1) infection causes the uncommon and deadly cancer known as adult T-cell leukemia/lymphoma (ATLL), which affects mature T cells. Its clinical appearance is varied, and its prognosis is often miserable. Drug resistance to conventional therapies confers significant therapeutic challenges in the management of ATLL. This review discusses the emerging role of epigenetic medical advances in the treatment of ATLL, focusing on DNA methyltransferase inhibitors, histone deacetylase inhibitors, histone methyltransferase inhibitors, and BET inhibitors. Indeed, several classes of epigenetic therapies currently exhibit trailed efficacy in preclinical and clinical studies: DNA methyltransferase inhibitors like azacitidine and decitabine reexpression of silenced tumor suppressors; histone deacetylase inhibitors like vorinostat and romidepsin induce cell cycle arrest and apoptosis; bromodomain and extra-terminal inhibitors like JQ1 disrupt oncogenic signaling pathways. Whereas preclinical and early clinical data indicate modest to good efficacy for such treatments, significant challenges remain. Here, we discuss the current state of understanding of epigenetic dysregulation in ATLL and appraise the evidence supporting the use of these epi-drugs. However, despite the opened doors of epigenetic treatment, much more research is required with regard to showing the best combinations of drugs and their resistance mechanisms, the minimization of adverse effects, and how this hope will eventually be translated into benefit for the patient with ATLL.

Inhibition of histone methyltransferase EZH2 for immune interception of colorectal cancer in Lynch syndrome

Colorectal precancers in Lynch syndrome (LS) exhibit a distinct immune profile, presenting unique opportunities for developing immune-interception strategies to prevent carcinogenesis. Epigenetic modulation by EZH2 of immune-related genes is implicated in the carcinogenesis of different cancer types, including colorectal cancer. This study utilizes a mouse model of LS and ex vivo colonic organoids to assess the effects of the EZH2 inhibitor GSK503 on immune regulatory pathways, tumorigenesis, and epigenetic reprogramming. Our findings revealed that GSK503 significantly increased CD4+ and CD8+ T cells in both splenocytes and colonic mucosa of treated mice compared with controls. Additionally, a preventive dose of GSK503 over 9 weeks notably reduced adenoma multiplicity, demonstrating its efficacy as a preventive modality. Single-cell RNA-Seq and molecular analyses showed activation of immune and apoptotic markers, along with a reduction in H3K27 methylation levels in colonic crypts. ChIP sequencing further revealed decreased levels of H3K27me3 and H3K4me1, while levels of the active enhancer marks H3K4me3 and H3K27Ac increased in treated mice. Collectively, these findings indicate that EZH2 inhibition enhances immune responses through epigenetic reprogramming in the genome of LS mice, establishing a promising framework for the clinical development of EZH2 inhibitors as a cancer prevention strategy for LS carriers.

The interplay of p16INK4a and non-coding RNAs: bridging cellular senescence, aging, and cancer

p16INK4a is a crucial tumor suppressor and regulator of cellular senescence, forming a molecular bridge between aging and cancer. Dysregulated p16INK4a expression is linked to both premature aging and cancer progression, where non-coding RNAs (ncRNAs) such as long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and small interfering RNAs (siRNAs) play key roles in modulating its function. These ncRNAs interact with p16INK4a through complex post-transcriptional and epigenetic mechanisms, influencing pathways critical to senescence and tumor suppression. In this review, we explore ncRNAs, including ANRIL, MIR31HG, UCA1, MALAT1, miR-24, miR-30, and miR-141, which collectively regulate p16INK4a expression, promoting or inhibiting pathways associated with cancer and aging. ANRIL and MIR31HG modulate p16INK4a silencing via interactions with polycomb repressive complexes (PRC), while miRNAs such as miR-24 and miR-30 target p16INK4a to influence cellular proliferation and senescence. This regulatory interplay underscores the therapeutic potential of ncRNA-targeted strategies to restore p16INK4a function. We summarize recent studies supporting that ncRNAs that control p16INK4a may be diagnostic biomarkers and therapeutic targets for age-related diseases and cancer.

Behavioral and genetic markers of susceptibility to escalate fentanyl intake

Background

The "loss of control" over drug consumption, present in opioid use disorder (OUD) and known as escalation of intake, is well-established in preclinical rodent models. However, little is known about how antecedent behavioral characteristics, such as valuation of hedonic reinforcers prior to drug use, may impact the trajectory of fentanyl intake over time. Moreover, it is unclear if distinct escalation phenotypes may be driven by genetic markers predictive of OUD susceptibility.

Methods

Male and female Sprague-Dawley rats (n=63) were trained in a sucrose reinforcement task using a progressive ratio schedule. Individual differences in responsivity to sucrose were hypothesized to predict escalation of fentanyl intake. Rats underwent daily 1-h acquisition sessions for i.v. fentanyl self-administration (2.5 μg/kg; FR1) for 7 days, followed by 21 6-h escalation sessions, then tissue from prefrontal cortex was collected for RNA sequencing and qPCR. Latent growth curve and group-based trajectory modeling were used, respectively, to evaluate the association between sucrose reinforcement and fentanyl self-administration and to identify whether distinct escalation phenotypes can be linked to gene expression patterns.

Results

Sucrose breakpoints were not predictive of fentanyl acquisition nor change during escalation, but did predict fentanyl intake on the first day of extended access to fentanyl. Permutation analyses did not identify associations between behavior and single gene expression when evaluated overall, or between our ascertained phenotypes. However, weighted genome correlation network analysis (WGCNA) and gene set enrichment analysis (GSEA) determined several gene modules linked to escalated fentanyl intake, including genes coding for voltage-gated potassium channels, calcium channels, and genes involved in excitatory synaptic signaling. Transcription factor analyses identified EZH2 and JARID2 as potential transcriptional regulators associated with escalated fentanyl intake. Genome-wide association study (GWAS) term categories were also generated and positively associated with terms relating to substance use disorders.

Discussion

Escalation of opioid intake is largely distinct from motivation for natural reward, such as sucrose. Further, the gene networks associated with fentanyl escalation suggest that engagement of select molecular pathways distinguish individuals with "addiction prone" behavioral endophenotypes, potentially representing druggable targets for opioid use disorder. Our extended in silico identification of SNPs and transcription factors associated with the "addiction prone" high escalating rats highlights the importance of integrating findings from translational preclinical models. Through a precision medicine approach, our results may aid in the development of patient-centered treatment options for those with OUD.

Alternative splicing of EZH2 regulated by SNRPB mediates hepatocellular carcinoma progression via BMP2 signaling pathway

Increasing evidence suggests that aberrant alternative splicing plays crucial roles in tumorigenesis. However, the function of EZH2 splice variants as well as the mechanism by which EZH2 alternative splicing occurs in hepatocellular carcinoma (HCC) remain elusive. Here, we analyzed both our own and published transcriptomic data, obtaining 19 splice variants of EZH2 in addition to canonical full-length EZH2-A in HCC. We found that expression of EZH2-A/EZH2-B in tumor tissues and cell lines was significantly higher than in normal tissues. Conversely, EZH2-C expression was lower in tumor tissues and cell lines than in normal tissues. Further functional analysis indicated that unlike full-length EZH2-A that promotes H3K27 methylation, EZH2-C reduced H3K27me3 levels. EZH2-C inhibited proliferation, migration, invasion of HCC cells. Moreover, EZH2-A and EZH2-C regulate the BMP2 signaling pathway oppositely. Mechanistically, EZH2's alternative splicing was mediated by splicing factor SNRPB. In summary, this study revealed that alternative splicing of EZH2 regulates HCC.

Competing endogenous RNA networks in ovarian cancer: from bench to bedside

Epithelial ovarian cancer is responsible for the majority of ovarian malignancies, and its highly invasive nature and chemoresistant development have been major obstacles to treating patients with mainstream treatments. In recent decades, the significance of microRNAs (miRNAs), circular RNAs (circRNAs), long non-coding RNAs (lncRNAs), and competing endogenous RNAs (ceRNAs) has been highlighted in ovarian cancer development. This hidden language between these RNAs has led to the discovery of enormous regulatory networks in ovarian cancer cells that substantially affect gene expression. Aside from providing ample opportunities for targeted therapies, circRNA- and lncRNA-mediated ceRNA network components provide invaluable biomarkers. The current study provides a comprehensive and up-to-date review of the recent findings on the significance of these ceRNA networks in the hallmarks of ovarian cancer oncogenesis, treatment, diagnosis, and prognosis. Also, it provides the authorship with future perspectives in the era of single-cell RNA sequencing and personalized medicine.

(B)On(e)-cohistones and the epigenetic alterations at the root of bone cancer

Identification of mutations in histones in a number of human neoplasms and developmental syndromes represents the most compelling evidence to date for a causal role of epigenetic perturbations in human disease. In most cases, these mutations have gain of function properties that cause deviation from normal developmental processes leading to embryo defects and/or neoplastic transformation. These exciting discoveries represent a step-change in our understanding of the role of chromatin (dys)regulation in development and disease. However, the mechanisms of action of oncogenic histone mutations (oncohistones) remain only partially understood. Here, we critically assess existing literature on oncohistones focussing mainly on bone neoplasms. We show how it is possible to draw parallels with some of the cell-autonomous mechanisms of action described in paediatric brain cancer, although the functions of oncohistones in bone tumours remain under-investigated. In this respect, it is becoming clear that histone mutations targeting the same residues display, at least in part, tissue-specific oncogenic mechanisms. Furthermore, it is emerging that cancer cells carrying oncohistones can modify the surrounding microenvironment to support growth and/or alter differentiation trajectories. A better understanding of oncohistone function in different neoplasms provide potential for identification of signalling that could be targeted therapeutically. Finally, we discuss some of the main concepts and future directions in this research area, while also drawing possible connections and parallels with other cancer epigenetic mechanisms.

Epigallocatechin-3-gallate inhibit the protein arginine methyltransferase 5 and enhancer of Zeste homolog 2 in breast cancer both in vitro and in vivo

PURPOSE

Histone methyltransferases are enzymes that selectively methylate lysine or arginine residues on both histone and non-histone proteins, categorized into lysine methyltransferases and arginine methyltransferases. Notably, EZH2 and PRMT5 are known for catalyzing trimethylation of H3 at K27 and symmetric dimethylation of H4 at R3, respectively. These methylation events are recognized as characteristic histone-repressive marks in cancer. The over expression of PRMT5 and EZH2 were reported in various cancers and recognized as a drug target. The study aims to explore the inhibitory potential of phytocompound, Epigallocatechin-3-gallate (EGCG), against PRMT5 and EZH2 in the breast cancer model.

METHODS

Screening of an array of phytocompounds was conducted through a combination of in-silico and in-vitro assays. Interactions between EGCG and human PRMT5: MEP50 and EZH2 were evaluated using molecular docking. Binding efficiency was validated, by Surface Plasmon Resonance studies and inhibitory potential was accessed by in vitro methylation followed by western blots, ELISA, and cell-based assays. In-vivo efficacy of EGCG was carried on cell line derived mice xenograft model.

RESULTS

EGCG demonstrated robust interactions with PRMT5:MEP50 complex and EZH2, particularly within the SAM binding site. Surface Plasmon Resonance analysis revealed strong binding affinity in nanomolar concentrations, particularly with PRMT5-MEP50 compared to EZH2. In-vitro assays confirmed EGCG's ability to inhibit PRMT5 and EZH2, leading to a decrease in their catalytic products, namely H4R3me2s and H3K27me3, respectively. EGCG treatment induced both autophagy and apoptosis invitro. In-vivo studies demonstrated significant reductions in tumor size and the proliferation marker ki67, accompanied by a decrease in histone repressive marks.

CONCLUSION

The findings suggest that EGCG effectively inhibits PRMT5 and EZH2, underscoring its potential for combined therapeutic strategies in cancer treatment.

H3K27me3 Loss in Central Nervous System Tumors: Diagnostic, Prognostic, and Therapeutic Implications

Central nervous system (CNS) tumors represent a formidable clinical challenge due to their molecular complexity and varied prognostic outcomes. This review delves into the pivotal role of the epigenetic marker H3K27me3 in the development and treatment of CNS tumors. H3K27me3, specifically the trimethylation of lysine 27 on the histone H3 protein, plays a crucial role in regulating gene expression and maintaining chromatin architecture (e.g., in X-chromosome inactivation). Notably, a reduction in H3K27me3 levels, frequently tied to mutations in the H3 gene family such as H3F3A and HIST1H3B, is evident in diverse brain tumor variants, including the diffuse midline glioma characterized by the H3K27M mutation and certain pediatric high-grade gliomas. The loss of H3K27me3 has been linked to more aggressive behavior in meningiomas, with the trimethylation loss associated with significantly shorter recurrence-free survival (RFS) among grade 2 meningiomas, albeit not within grade 1 tumors. Pediatric posterior fossa ependymomas characterized by a lowered H3K27me3 and DNA hypomethylation exhibit poor prognosis, underscoring the prognostic significance of these epigenetic alterations in CNS tumors. Comprehending the role of H3K27me3 in CNS tumors is vital for advancing diagnostic tools and therapeutic interventions, with the goal of enhancing patient outcomes and quality of life. This review underscores the importance of ongoing investigations into H3K27me to refine and optimize management strategies for CNS tumors, paving the way for improved personalized medicine practices in oncology.

Non-oncogene dependencies: Novel opportunities for cancer therapy

Targeting oncogene addictions have changed the history of subsets of malignancies and continues to represent an excellent therapeutic opportunity. Nonetheless, alternative strategies are required to treat malignancies driven by undruggable oncogenes or loss of tumor suppressor genes and to overcome drug resistance also occurring in cancers addicted to actionable drivers. The discovery of non-oncogene addiction (NOA) uncovered novel therapeutically exploitable "Achilles' heels". NOA refers to genes/pathways not oncogenic per sé but essential for the tumor cell growth/survival while dispensable for normal cells. The clinical success of several classes of conventional and molecular targeted agents can be ascribed to their impact on both tumor cell-associated intrinsic as well as microenvironment-related extrinsic NOA. The integration of genetic, computational and pharmacological high-throughput approaches led to the identification of an expanded repertoire of synthetic lethality interactions implicating NOA targets. Only a few of them have been translated into the clinics as most NOA vulnerabilities are not easily druggable or appealing targets. Nonetheless, their identification has provided in-depth knowledge of tumor pathobiology and suggested novel therapeutic opportunities. Here, we summarize conceptual framework of intrinsic and extrinsic NOA providing exploitable vulnerabilities. Conventional and emerging methodological approaches used to disclose NOA dependencies are reported together with their limits. We illustrate NOA paradigmatic and peculiar examples and outline the functional/mechanistic aspects, potential druggability and translational interest. Finally, we comment on difficulties in exploiting the NOA-generated knowledge to develop novel therapeutic approaches to be translated into the clinics and to fully harness the potential of clinically available drugs.

EZH2-associated tumor malignancy: A prominent target for cancer treatment

The discussion in this review centers around the significant relationships between EZH2 and the initiation, progression, metastasis, metabolism, drug resistance, and immune regulation of cancer. Polycomb group (PcG) proteins, which encompass two primary Polycomb repressor complexes (PRC1 and PRC2), have been categorized. PRC2 consists mainly of four subunits, namely EZH2, EED, SUZ12, and RbAp46/48. As the crucial catalytic component within the PRC2 complex, EZH2 plays a pivotal role in controlling a wide range of biological processes. Overexpression/mutations of EZH2 have been detected in a wide variety of tumors. Several mechanisms of EZH regulation have been identified, including regulation EZH2 mRNA by miRNAs, LncRNAs, accessibility to DNA via DNA-binding proteins, post-translational modifications, and transcriptional regulation. EZH2 signaling triggers cancer progression and may intervene with anti-tumor immunity; therefore it has charmed attention as an effective therapeutic target in cancer therapy. Numerous nucleic acid-based therapies have been used in the modification of EZH2. In addition to gene therapy approaches, pharmaceutical compounds can be used to target the EZH2 signaling pathway in the treatment of cancer. EZH2-associated tumor cells and immune cells enhance the effects of the immune response in a variety of human malignancies. The combination of epigenetic modifying agents, such as anti-EZH2 compounds with immunotherapy, could potentially be efficacious even in the context of immunosuppressive tumors. Summary, understanding the mechanisms underlying resistance to EZH2 inhibitors may facilitate the development of novel drugs to prevent or treat relapse in treated patients.

Macrophage-mediated myelin recycling fuels brain cancer malignancy

Tumors growing in metabolically challenged environments, such as glioblastoma in the brain, are particularly reliant on crosstalk with their tumor microenvironment (TME) to satisfy their high energetic needs. To study the intricacies of this metabolic interplay, we interrogated the heterogeneity of the glioblastoma TME using single-cell and multi-omics analyses and identified metabolically rewired tumor-associated macrophage (TAM) subpopulations with pro-tumorigenic properties. These TAM subsets, termed lipid-laden macrophages (LLMs) to reflect their cholesterol accumulation, are epigenetically rewired, display immunosuppressive features, and are enriched in the aggressive mesenchymal glioblastoma subtype. Engulfment of cholesterol-rich myelin debris endows subsets of TAMs to acquire an LLM phenotype. Subsequently, LLMs directly transfer myelin-derived lipids to cancer cells in an LXR/Abca1-dependent manner, thereby fueling the heightened metabolic demands of mesenchymal glioblastoma. Our work provides an in-depth understanding of the immune-metabolic interplay during glioblastoma progression, thereby laying a framework to unveil targetable metabolic vulnerabilities in glioblastoma.

Novel insights on oral squamous cell carcinoma management using long non-coding RNAs

Oral squamous cell carcinoma (OSCC) is one of the most prevalent forms of head and neck squamous cell carcinomas (HNSCC) with a poor overall survival rate (about 50%), particularly in cases of metastasis. RNA-based cancer biomarkers are a relatively advanced concept, and non-coding RNAs currently have shown promising roles in the detection and treatment of various malignancies. This review underlines the function of long non-coding RNAs (lncRNAs) in the OSCC and its subsequent clinical implications. LncRNAs, a class of non-coding RNAs, are larger than 200 nucleotides and resemble mRNA in numerous ways. However, unlike mRNA, lncRNA regulates multiple druggable and non-druggable signaling molecules through simultaneous interaction with DNA, RNA, proteins, or microRNAs depending on concentration and localization in cells. Upregulation of oncogenic lncRNAs and down-regulation of tumor suppressor lncRNAs are evident in OSCC tissues and body fluids such as blood and saliva indicating their potential as valuable biomarkers. Targeted inhibition of candidate oncogenic lncRNAs or over-expression of tumor suppressor lncRNAs showed potential therapeutic roles in in-vivo animal models. The types of lncRNAs that are expressed differentially in OSCC tissue and bodily fluids have been systematically documented with specificity and sensitivity. This review thoroughly discusses the biological functions of such lncRNAs in OSCC cell survival, proliferation, invasion, migration, metastasis, angiogenesis, metabolism, epigenetic modification, tumor immune microenvironment, and drug resistance. Subsequently, we addressed the diagnostic and therapeutic importance of lncRNAs in OSCC pre-clinical and clinical systems, providing details on ongoing research and outlining potential future directions for advancements in this field. In essence, this review could be a valuable resource by offering comprehensive and current insights into lncRNAs in OSCC for researchers in fundamental and clinical domains.

The Role of Long Non-Coding RNAs in Ovarian Cancer Cells

Among the most deadly malignancies that strike women worldwide, ovarian cancer is still one of the most common. The primary factor affecting a patient's survival is early lesion discovery. Unfortunately, because ovarian cancer is a sneaky illness that usually manifests as nonspecific symptoms only in advanced stages, its early detection and screening are challenging. A lot of research is being conducted on effective methods of diagnosing and treating ovarian cancer. Recently, non-coding RNAs (ncRNAs) have gained great popularity, which are considered to be the main regulators of many cellular processes, especially those occurring in cancer. LncRNAs are also being studied for their therapeutic use in the treatment of ovarian cancer and their use in diagnostics and as indicators of poor prognosis. In this article, we reviewed lncRNAs described in the literature that may play an important role in ovarian cancer.

Epigenetics and immunotherapy in colorectal cancer: progress and promise

Colorectal cancer (CRC) is a common malignant tumor with the third and second highest incidence and mortality rates among various malignant tumors. Despite significant advancements in the present therapy for CRC, the majority of CRC cases feature proficient mismatch repair/microsatellite stability and have no response to immunotherapy. Therefore, the search for new treatment options holds immense importance in the diagnosis and treatment of CRC. In recent years, clinical research on immunotherapy combined with epigenetic therapy has gradually increased, which may bring hope for these patients. This review explores the role of epigenetic regulation in exerting antitumor effects through its action on immune cell function and highlights the potential of certain epigenetic genes that can be used as markers of immunotherapy to predict therapeutic efficacy. We also discuss the application of epigenetic drug sensitization immunotherapy to develop new treatment options combining epigenetic therapy and immunotherapy.

microRNA 21 and long non-coding RNAs interplays underlie cancer pathophysiology: A narrative review

Non-coding RNAs (ncRNAs) are a diverse group of functional RNA molecules that lack the ability to code for proteins. Despite missing this traditional role, ncRNAs have emerged as crucial regulators of various biological processes and have been implicated in the development and progression of many diseases, including cancer. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are two prominent classes of ncRNAs that have emerged as key players in cancer pathophysiology. In particular, miR-21 has been reported to exhibit oncogenic roles in various forms of human cancer, including prostate, breast, lung, and colorectal cancer. In this context, miR-21 overexpression is closely associated with tumor proliferation, growth, invasion, angiogenesis, and chemoresistance, whereas miR-21 inactivation is linked to the regression of most tumor-related processes. Accordingly, miR-21 is a crucial modulator of various canonical oncogenic pathways such as PTEN/PI3K/Akt, Wnt/β-catenin, STAT, p53, MMP2, and MMP9. Moreover, interplays between lncRNA and miRNA further complicate the regulatory mechanisms underlying tumor development and progression. In this regard, several lncRNAs have been found to interact with miR-21 and, by functioning as competitive endogenous RNAs (ceRNAs) or miRNA sponges, can modulate cancer tumorigenesis. This work presents and discusses recent findings highlighting the roles and pathophysiological implications of the miR-21-lncRNA regulatory axis in cancer occurrence, development, and progression. The data collected indicate that specific lncRNAs, such as MEG3, CASC2, and GAS5, are strongly associated with miR-21 in various types of cancer, including gastric, cervical, lung, and glioma. Indeed, these lncRNAs are well-known tumor suppressors and are commonly downregulated in different types of tumors. Conversely, by modulating various mechanisms and oncogenic signaling pathways, their overexpression has been linked with preventing tumor formation and development. This review highlights the significance of these regulatory pathways in cancer and their potential for use in cancer therapy as diagnostic and prognostic markers.

Brain Stem Glioma Recurrence: Exploring the Therapeutic Frontiers

Gliomas of the brainstem represent a small percentage of central nervous system gliomas in adults. Due to the proximity of the tumor to critical structures, radical surgery is highly challenging and limited to selected cases. In addition, postoperative treatments, which become exclusive to non-operable patients, do not guarantee satisfactory disease control, making the progression of the disease inevitable. Currently, there is a lack of therapeutic options to control tumor growth after the diagnosis of recurrence. The rarity of these tumors, their distinct behavioral characteristics, and the limited availability of tumor tissue necessary for the development of prognostic and predictive biomarkers contribute to the absence of a standardized approach for treating recurrent brainstem gliomas. A salvage radiotherapy (RT) retreatment could represent a promising approach for recurrent brainstem gliomas. However, to date, it has been mainly evaluated in pediatric cases, with few experiences available to assess the most appropriate RT dose, safety, and clinical responses in adult patients. This comprehensive review aims to identify instances of adult patients with recurrent brainstem gliomas subjected to a secondary course of RT, with a specific focus on the analysis of treatment-related toxicity and outcomes. Through this investigation, we endeavor to contribute valuable insights into the viability and efficacy of salvage RT retreatment in managing recurrent brainstem gliomas in the adult population.

EZH2 Inhibition to Counteract Oral Cancer Progression through Wnt/β-Catenin Pathway Modulation

Oral squamous cell carcinoma (OSCC) is one of the most common human malignancies worldwide. The molecular mechanisms of OSCC pathogenesis are still unknown; however, in recent years, several reports have focused on the role of enhancer of zeste homolog 2 (EZH2) in OSCC. Therefore, in this study we aimed to investigate the effects of GSK343, a selective EZH2 inhibitor, and its impact on the signaling pathways in OSCC, using an in vitro and in vivo orthotopic model. In the in vitro model, GSK343 (1, 10, and 25 μM) significantly decreased OSCC cell viability and cell migration through EZH2 inhibition, modulating NF-κB/IκBα pathway activation and eNOS, VEGF, and TGFβ expression, important markers of angiogenesis. In the in vivo model, GSK343 (5 mg/kg and 10 mg/kg) restored tongue tissue architecture and reduced tumor progression through EZH2 inhibition and Wnt/β-catenin signaling pathway modulation. Moreover, GSK343 reduced the expression of inflammatory mediators; eNOS and TGFβ, markers of angiogenesis; and CD31 and CD34, markers of micro vessel density, respectively. In conclusion, our data demonstrate that GSK343 counteracts oral cancer progression through EZH2/Wnt/β-catenin pathway modulation, suggesting that it could be a promising therapeutic approach for OSCC management.

Salicylaldehyde-derived piperazine-functionalized hydrazone ligand-based Pt(II) complexes: inhibition of EZH2-dependent tumorigenesis in pancreatic ductal adenocarcinoma, synergism with PARP inhibitors and enhanced apoptosis

Piperazine is an important functional unit of many clinically approved drugs, including chemotherapeutic agents. In the current study, methyl piperazine was incorporated and eight salicylaldehyde-derived piperazine-functionalized hydrazone ONN-donor ligands (L) and their Pt(II) complexes (L-PtCl) were prepared. The structures of all these ligands (L1-L8) and Pt(II) complexes (C1-C8) were determined using 1H and 13C NMR, UV-vis, FT-IR and HR-ESI MS analyses, whereas the structures of C1, C5, C6, C7 and C8 were determined in the solid state using single crystal X-ray diffraction analysis. Solution state stabilities of C3, C4, C5 and C6 were determined via time-dependent UV-vis spectroscopy. All these complexes (C1-C8) were studied for their anticancer effect in pancreatic ductal adenocarcinoma cells, including BxPC3, MIAPaCa-2 and PANC1 cells. C1-C8 displayed a potential cytotoxic effect in all these cancer cells, among which C5, C6 and C8 showed the strongest inhibitory effect in comparison with standard chemotherapeutic agents, including 5-fluorouracil (5-FU), cisplatin (CP), oxaliplatin and doxorubicin (DOX). C5, C6 and C8 suppressed the growth of pancreatic cancer cells in a dose-dependent manner. Moreover, C5, C6 and C8 inhibited clonogenic potential and invasion ability and induced apoptosis in PANC1 cells. Importantly, C5, C6 and C8 synergized the anticancer effect with PARP inhibitors, including olaparib, veliparib and niraparib, in pancreatic cancer cells, thus suggesting an important role of C5, C6 and C8 in induction of apoptosis in combination with PARP inhibitors. C5 combined with PARP inhibitors induced caspase3/7 activity and suppressed ATP production. Mechanistically, C5, C6 and C8 inhibited EZH2 protein expression to suppress EZH2-dependent tumorigenesis. Overall, these results highlighted the importance of these piperazine-functionalized Pt(II) complexes as potential anticancer agents to suppress pancreatic ductal adenocarcinoma tumorigenesis by targeting the EZH2-dependent pathway.

ARID1A in Gynecologic Precancers and Cancers

The highest frequency of genetic alterations in the tumor suppressor ARID1A occurs in malignancies of the female reproductive tract. The prevalence of ARID1A alterations in gynecologic precancers and cancers is summarized from the literature, and the putative mechanisms of tumor suppressive action examined both in benign/precursor lesions including endometriosis and atypical hyperplasia and in malignancies of the ovary, uterus, cervix and vagina. ARID1A alterations in gynecologic cancers are usually loss-of-function mutations, resulting in diminished or absent protein expression. ARID1A deficiency results in pleiotropic downstream effects related not only to its role in transcriptional regulation as a SWI/SNF complex subunit, but also related to the functions of ARID1A in DNA replication and repair, immune modulation, cell cycle progression, endoplasmic reticulum (ER) stress and oxidative stress. The most promising actionable signaling pathway interactions and therapeutic vulnerabilities of ARID1A mutated cancers are presented with a critical review of the currently available experimental and clinical evidence. The role of ARID1A in response to chemotherapeutic agents, radiation therapy and immunotherapy is also addressed. In summary, the multi-faceted role of ARID1A mutation in precancer and cancer is examined through a clinical lens focused on development of novel preventive and therapeutic interventions for gynecological cancers.

Comprehensive Target Engagement by the EZH2 Inhibitor Tulmimetostat Allows for Targeting of ARID1A Mutant Cancers

Recurrent somatic mutations in the BRG1/BRM-associated factor (BAF) chromatin remodeling complex subunit ARID1A occur frequently in advanced urothelial, endometrial, and ovarian clear cell carcinomas, creating an alternative chromatin state that may be exploited therapeutically. The histone methyltransferase EZH2 has been previously identified as targetable vulnerability in the context of ARID1A mutations. In this study, we describe the discovery of tulmimetostat, an orally available, clinical stage EZH2 inhibitor, and it elucidates the aspects of its application potential in ARID1A mutant tumors. Tulmimetostat administration achieved efficacy in multiple ARID1A mutant bladder, ovarian, and endometrial tumor models and improved cisplatin response in chemotherapy-resistant models. Consistent with its comprehensive and durable level of target coverage, tulmimetostat demonstrated greater efficacy than other PRC2-targeted inhibitors at comparable or lower exposures in a bladder cancer xenograft mouse model. Tulmimetostat mediated extensive changes in gene expression, in addition to a profound reduction in global H3K27me3 levels in tumors. Phase I clinical pharmacokinetic and pharmacodynamic data indicated that tulmimetostat exhibits durable exposure and profound target engagement. Importantly, a tulmimetostat controlled gene expression signature identified in whole blood from a cohort of 32 patients with cancer correlated with tulmimetostat exposure, representing a pharmacodynamic marker for the assessment of target coverage for PRC2-targeted agents in the clinic. Collectively, these data suggest that tulmimetostat has the potential to achieve clinical benefit in solid tumors as a monotherapy but also in combination with chemotherapeutic agents, and may be beneficial in various indications with recurrent ARID1A mutations. Significance: The EZH2 inhibitor tulmimetostat achieves comprehensive target inhibition in ARID1A mutant solid tumor models and cancer patients that can be assessed with a pharmacodynamic gene signature in peripheral blood.

An update on existing therapeutic options and status of novel anti-metastatic agents in breast cancer: Elucidating the molecular mechanisms underlying the pleiotropic action of Withania somnifera (Indian ginseng) in breast cancer attenuation

Major significant advancements in pharmacology and drug technology have been made to heighten the impact of cancer therapies, improving the life expectancy of subjects diagnosed with malignancy. Statistically, 99% of breast cancers occur in women while 0.5-1% occur in men, the female gender being the strongest breast cancer risk factor. Despite several breakthroughs, breast cancer continues to have a worldwide impact and is one of the leading causes of mortality. Additionally, resistance to therapy is a crucial factor enabling cancer cell persistence and resurgence. As a result, the search and discovery of novel modulatory agents and effective therapies capable of controlling tumor progression and cancer cell proliferation is critical. Withania somnifera (L.) Dunal (WS), commonly known as Indian ginseng, has long been used traditionally for the treatment of several ailments in the Indian context. Recently, WS and its phytoconstituents have shown promising anti-breast cancer properties and, as such, can be employed as prophylactic as well as therapeutic adjuncts to the main line of breast cancer treatment. The present review is an attempt to explore and provide experimental evidences in support of the prophylactic and therapeutic potential of WS in breast cancer, along with a deeper insight into the multiple molecular mechanisms and novel targets through which it acts against breast and other hormonally-induced cancers viz. ovarian, uterine and cervical. This exploration might prove crucial in providing better understanding of breast cancer progression and metastasis and its use as an adjunct in improving disease prognosis and therapeutic outcome.

The role of extracellular vesicles in cancer

Extracellular vesicles (EVs), which include small EVs such as exosomes, play a critical role in intercellular communication and are produced by both cancer and non-cancer cells. Several studies have shown that cancer cells exploit various strategies to regulate the biogenesis, composition, and functions of EVs primarily to promote cancer progression. Given that exosomes originate from major sorting hubs at the limiting membrane of endosomes, they are central to a signaling network that connects external stimuli with intrinsic tumor cell features. Exosomes contain diverse repertoires of molecular cargos, such as proteins, lipids, and nucleic acids, which determine their heterogeneity and functional properties in cancer progression. Therefore, targeting exosome biogenesis will enhance our understanding of tumorigenesis and also promote the discovery of novel approaches for cancer therapy. In this chapter we summarize the machinery of exosome biogenesis and the local, distant, and systemic effects of exosomes released by cancer cells. Furthermore, we explore how these exosomes regulate the anti-tumor immune response and epigenetic mechanisms to sustain cancer progression and their implications in cancer prevention and treatment.

Therapeutic implications of signaling pathways and tumor microenvironment interactions in esophageal cancer

Esophageal cancer (EC) is significantly influenced by the tumor microenvironment (TME) and altered signaling pathways. Downregulating these pathways in EC is essential for suppressing tumor development, preventing metastasis, and enhancing therapeutic outcomes. This approach can increase tumor sensitivity to treatments, enhance patient outcomes, and inhibit cancer cell proliferation and spread. The TME, comprising cellular and non-cellular elements surrounding the tumor, significantly influences EC's development, course, and treatment responsiveness. Understanding the complex relationships within the TME is crucial for developing successful EC treatments. Immunotherapy is a vital TME treatment for EC. However, the heterogeneity within the TME limits the application of anticancer drugs outside clinical settings. Therefore, identifying reliable microenvironmental biomarkers that can detect therapeutic responses before initiating therapy is crucial. Combining approaches focusing on EC signaling pathways with TME can enhance treatment outcomes. This integrated strategy aims to interfere with essential signaling pathways promoting cancer spread while disrupting factors encouraging tumor development. Unraveling aberrant signaling pathways and TME components can lead to more focused and efficient treatment approaches, identifying specific cellular targets for treatments. Targeting the TME and signaling pathways may reduce metastasis risk by interfering with mechanisms facilitating cancer cell invasion and dissemination. In conclusion, this integrative strategy has significant potential for improving patient outcomes and advancing EC research and therapy. This review discusses the altered signaling pathways and TME in EC, focusing on potential future therapeutics.

Translation of Epigenetics in Cell-Free DNA Liquid Biopsy Technology and Precision Oncology

Technological advancements in cell-free DNA (cfDNA) liquid biopsy have triggered exponential growth in numerous clinical applications. While cfDNA-based liquid biopsy has made significant strides in personalizing cancer treatment, the exploration and translation of epigenetics in liquid biopsy to clinical practice is still nascent. This comprehensive review seeks to provide a broad yet in-depth narrative of the present status of epigenetics in cfDNA liquid biopsy and its associated challenges. It highlights the potential of epigenetics in cfDNA liquid biopsy technologies with the hopes of enhancing its clinical translation. The momentum of cfDNA liquid biopsy technologies in recent years has propelled epigenetics to the forefront of molecular biology. We have only begun to reveal the true potential of epigenetics in both our understanding of disease and leveraging epigenetics in the diagnostic and therapeutic domains. Recent clinical applications of epigenetics-based cfDNA liquid biopsy revolve around DNA methylation in screening and early cancer detection, leading to the development of multi-cancer early detection tests and the capability to pinpoint tissues of origin. The clinical application of epigenetics in cfDNA liquid biopsy in minimal residual disease, monitoring, and surveillance are at their initial stages. A notable advancement in fragmentation patterns analysis has created a new avenue for epigenetic biomarkers. However, the widespread application of cfDNA liquid biopsy has many challenges, including biomarker sensitivity, specificity, logistics including infrastructure and personnel, data processing, handling, results interpretation, accessibility, and cost effectiveness. Exploring and translating epigenetics in cfDNA liquid biopsy technology can transform our understanding and perception of cancer prevention and management. cfDNA liquid biopsy has great potential in precision oncology to revolutionize conventional ways of early cancer detection, monitoring residual disease, treatment response, surveillance, and drug development. Adapting the implementation of liquid biopsy workflow to the local policy worldwide and developing point-of-care testing holds great potential to overcome global cancer disparity and improve cancer outcomes.

Epigenetic contribution to cancer

Epigenetics has transformed our understanding of cancer by revealing how changes in gene activity, which do not alter the DNA itself, can initiate and progress the disease. These changes include adjustments in DNA methylation, histone configuration, and non-coding RNA activity. For instance, DNA methylation can inactivate genes that typically protect against cancer, leading to broader genomic instability. Histone modifications can alter how tightly DNA is wound, influencing which genes are active or silenced; while non-coding RNAs can interfere with the messages that direct protein production, impacting cancer-related processes. Unlike genetic mutations, which are permanent and irreversible, epigenetic changes provide a malleable target for therapeutic intervention, allowing potentially reversible adjustments to gene expression patterns. This flexibility is essential in the complex landscape of cancer where static genetic solutions may be insufficient. Additionally, epigenetics bridges the gap between genetic predispositions and environmental influences on cancer, offering a comprehensive framework for understanding how lifestyle factors and external exposures impact cancer risk and progression. The integration of epigenetics into cancer research not only enhances our understanding of the disease but also opens innovative avenues for intervention that were previously unexplored in traditional genetic-focused studies. Technologies like advanced sequencing and precise epigenetic modification are paving the way for early cancer detection and more personalized treatment approaches, highlighting the critical role of epigenetics in modern cancer care.

Decoding the tumour-modulatory roles of LIMK2

LIM domains kinase 2 (LIMK2) is a 72 kDa protein that regulates actin and cytoskeleton reorganization. Once phosphorylated by its upstream activator (ROCK1), LIMK2 can phosphorylate cofilin to inactivate it. This relieves the levering stress on actin and allows polymerization to occur. Actin rearrangement is essential in regulating cell cycle progression, apoptosis, and migration. Dysregulation of the ROCK1/LIMK2/cofilin pathway has been reported to link to the development of various solid cancers such as breast, lung, and prostate cancer and liquid cancer like leukemia. This review aims to assess the findings from multiple reported in vitro, in vivo, and clinical studies on the potential tumour-regulatory role of LIMK2 in different human cancers. The findings of the selected literature unraveled that activated AKT, EGF, and TGF-β pathways can upregulate the activities of the ROCK1/LIMK2/cofilin pathway. Besides cofilin, LIMK2 can modulate the cellular levels of other proteins, such as TPPP1, to promote microtubule polymerization. The tumour suppressor protein p53 can transactivate LIMK2b, a splice variant of LIMK2, to induce cell cycle arrest and allow DNA repair to occur before the cell enters the next phase of the cell cycle. Additionally, several non-coding RNAs, such as miR-135a and miR-939-5p, could also epigenetically regulate the expression of LIMK2. Since the expression of LIMK2 is dysregulated in several human cancers, measuring the tissue expression of LIMK2 could potentially help diagnose cancer and predict patient prognosis. As LIMK2 could play tumour-promoting and tumour-inhibiting roles in cancer development, more investigation should be conducted to carefully evaluate whether introducing a LIMK2 inhibitor in cancer patients could slow cancer progression without posing clinical harms.

Epigenetic regulation of breast cancer metastasis

Breast cancer is the most frequently diagnosed malignancy and the second leading cause of cancer-related mortality among women worldwide. Recurrent metastasis is associated with poor patient outcomes and poses a significant challenge in breast cancer therapies. Cancer cells adapting to a new tissue microenvironment is the key event in distant metastasis development, where the disseminating tumor cells are likely to acquire genetic and epigenetic alterations during the process of metastatic colonization. Despite several decades of research in this field, the exact mechanisms governing metastasis are not fully understood. However, emerging body of evidence indicates that in addition to genetic changes, epigenetic reprogramming of cancer cells and the metastatic niche are paramount toward successful metastasis. Here, we review and discuss the latest knowledge about the salient attributes of metastasis and epigenetic regulation in breast cancer and crucial research domains that need further investigation.

Targeting EED as a key PRC2 complex mediator toward novel epigenetic therapeutics

EED within the PRC2 complex is crucial for chromatin regulation particularly in tumor development, making its inhibition a promising epigenetic therapeutic strategy. Significant advancement in PRC2 inhibitor development has been achieved with an approved EZH2 inhibitor in the market and with others in the clinical trials. However, current EZH2 inhibitors are limited to specific blood cancers and encounter therapeutic resistance. EED stabilizes PRC2 complex and enhances its activity through unique allosteric mechanisms, thereby acting as both a scaffold protein and a recognizer of H3K27me3 making it an attractive drug target. This review provides an overview of epigenetic therapeutic strategies targeting EED, including allosteric inhibitors, PPI inhibitors, and PROTACs, together with brief discussions on the relevant challenges, opportunities, and future directions.

Targeting notch-related lncRNAs in cancer: Insights into molecular regulation and therapeutic potential

Cancer is a group of diseases marked by unchecked cell proliferation and the ability for the disease to metastasize to different body areas. Enhancements in treatment and early detection are crucial for improved outcomes. LncRNAs are RNA molecules that encode proteins and have a length of more than 200 nucleotides. LncRNAs are crucial for chromatin architecture, gene regulation, and other cellular activities that impact both normal growth & pathological processes, even though they are unable to code for proteins. LncRNAs have emerged as significant regulators in the study of cancer biology, with a focus on their intricate function in the Notch signaling pathway. The imbalance of this pathway is often linked to a variety of malignancies. Notch signaling is essential for cellular functions like proliferation, differentiation, and death. The cellular response is shaped by these lncRNAs through their modulation of essential Notch pathway constituents such as receptors, ligands, and downstream effectors around it. Furthermore, a variety of cancer types exhibit irregular expression of Notch-related lncRNAs, underscoring their potential use as therapeutic targets and diagnostic markers. Gaining an understanding of the molecular processes behind the interaction between the Notch pathway and lncRNAs will help you better understand the intricate regulatory networks that control the development of cancer. This can open up new possibilities for individualized treatment plans and focused therapeutic interventions. The intricate relationships between lncRNAs & the Notch pathway in cancer are examined in this review.

Deletion of a conserved genomic region associated with adolescent idiopathic scoliosis leads to vertebral rotation in mice

Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis, in which spinal curvature develops in adolescence, and 90% of patients are female. Scoliosis is a debilitating disease that often requires bracing or surgery in severe cases. AIS affects 2%-5.2% of the population; however, the biological origin of the disease remains poorly understood. In this study, we aimed to determine the function of a highly conserved genomic region previously linked to AIS using a mouse model generated by CRISPR-CAS9 gene editing to knockout this area of the genome to understand better its contribution to AIS, which we named AIS_CRMΔ. We also investigated the upstream factors that regulate the activity of this enhancer in vivo, whether the spatial expression of the LBX1 protein would change with the loss of AIS-CRM function, and whether any phenotype would arise after deletion of this region. We found a significant increase in mRNA expression in the developing neural tube at E10.5, and E12.5, for not only Lbx1 but also other neighboring genes. Adult knockout mice showed vertebral rotation and proprioceptive deficits, also observed in human AIS patients. In conclusion, our study sheds light on the elusive biological origins of AIS, by targeting and investigating a highly conserved genomic region linked to AIS in humans. These findings provide valuable insights into the function of the investigated region and contribute to our understanding of the underlying causes of this debilitating disease.

Emerging New Targets in Systemic Therapy for Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a heterogeneous cancer composed of distinct molecular and pathologic subtypes. Unfortunately, MPM is aggressive, and current therapies for advanced, unresectable disease remain limited to cytotoxic chemotherapy and immunotherapy. Our understanding of the genomic landscape of MPM is steadily growing, while the discovery of effective targeted therapies in MPM has advanced more slowly than in other solid tumors. Given the prevalence of alterations in tumor suppressor genes in MPM, it has been challenging to identify actionable targets. However, efforts to characterize the genetic signatures in MPM over the last decade have led to a range of novel targeted therapeutics entering early-phase clinical trials. In this review, we discuss the advancements made thus far in targeted systemic therapies in MPM and the future direction of targeted strategies in patients with advanced MPM.

MTOR modulation induces selective perturbations in histone methylation which influence the anti-proliferative effects of mTOR inhibitors

Emerging data suggest a significant cross-talk between metabolic and epigenetic programs. However, the relationship between the mechanistic target of rapamycin (mTOR), which is a pivotal metabolic regulator, and epigenetic modifications remains poorly understood. Our results show that mTORC1 activation caused by the abrogation of its negative regulator tuberous sclerosis complex 2 (TSC2) coincides with increased levels of the histone modification H3K27me3 but not H3K4me3 or H3K9me3. This selective H3K27me3 induction was mediated via 4E-BP-dependent increase in EZH2 protein levels. Surprisingly, mTOR inhibition also selectively induced H3K27me3. This was independent of TSC2, and was paralleled by reduced EZH2 and increased EZH1 protein levels. Notably, the ability of mTOR inhibitors to induce H3K27me3 levels was positively correlated with their anti-proliferative effects. Collectively, our findings demonstrate that both activation and inhibition of mTOR selectively increase H3K27me3 by distinct mechanisms, whereby the induction of H3K27me3 may potentiate the anti-proliferative effects of mTOR inhibitors.

MAL expression downregulation through suppressive H3K27me3 marks at the promoter in HPV16-related cervical cancers is prognostically relevant and manifested by the interplay of novel MAL antisense long noncoding RNA AC103563.8, E7 oncoprotein and EZH2

BACKGROUND

MAL (T-lymphocyte maturation-associated protein) is highly downregulated in most cancers, including cervical cancer (CaCx), attributable to promoter hypermethylation. Long noncoding RNA genes (lncGs) play pivotal roles in CaCx pathogenesis, by interacting with human papillomavirus (HPV)-encoded oncoproteins, and epigenetically regulating coding gene expression. Hence, we attempted to decipher the impact and underlying mechanisms of MAL downregulation in HPV16-related CaCx pathogenesis, by interrogating the interactive roles of MAL antisense lncRNA AC103563.8, E7 oncoprotein and PRC2 complex protein, EZH2.

RESULTS

Employing strand-specific RNA-sequencing, we confirmed the downregulated expression of MAL in association with poor overall survival of CaCx patients bearing HPV16, along with its antisense long noncoding RNA (lncRNA) AC103563.8. The strength of positive correlation between MAL and AC103563.8 was significantly high among patients compared to normal individuals. While downregulated expression of MAL was significantly associated with poor overall survival of CaCx patients bearing HPV16, AC103563.8 did not reveal any such association. We confirmed the enrichment of chromatin suppressive mark, H3K27me3 at MAL promoter, using ChIP-qPCR in HPV16-positive SiHa cells. Subsequent E7 knockdown in such cells significantly increased MAL expression, concomitant with decreased EZH2 expression and H3K27me3 marks at MAL promoter. In silico analysis revealed that both E7 and EZH2 bear the potential of interacting with AC103563.8, at the same binding domain. RNA immunoprecipitation with anti-EZH2 and anti-E7 antibodies, respectively, and subsequent quantitative PCR analysis in E7-silenced and unperturbed SiHa cells confirmed the interaction of AC103563.8 with EZH2 and E7, respectively. Apparently, AC103563.8 seems to preclude EZH2 and bind with E7, failing to block EZH2 function in patients. Thereby, enhanced EZH2 expression in the presence of E7 could potentially inactivate the MAL promoter through H3K27me3 marks, corroborating our previous results of MAL expression downregulation in patients.

CONCLUSION

AC103563.8-E7-EZH2 axis, therefore, appears to crucially regulate the expression of MAL, through chromatin inactivation in HPV16-CaCx pathogenesis, warranting therapeutic strategy development.

Signaling pathways governing the behaviors of leukemia stem cells

Leukemia is a malignancy in the blood that develops from the lymphatic system and bone marrow. Although various treatment options have been used for different types of leukemia, understanding the molecular pathways involved in the development and progression of leukemia is necessary. Recent studies showed that leukemia stem cells (LSCs) play essential roles in the pathogenesis of leukemia by targeting several signaling pathways, including Notch, Wnt, Hedgehog, and STAT3. LSCs are highly proliferative cells that stimulate tumor initiation, migration, EMT, and drug resistance. This review summarizes cellular pathways that stimulate and prevent LSCs' self-renewal, metastasis, and tumorigenesis.

Prognostic and predictive biomarkers in central nervous system tumours: the molecular state of play

Central nervous system (CNS) tumours were one of the first cancer types to adopt and integrate molecular profiling into routine clinical diagnosis in 2016. The vast majority of these biomarkers, used to discriminate between tumour types, also offered prognostic information. With the advent of The Cancer Genome Atlas (TCGA) and other large genomic datasets, further prognostic sub-stratification was possible within tumour types, leading to increased precision in CNS tumour grading. This review outlines the evolution of the molecular landscape of adult CNS tumours, through the prism of World Health Organization (WHO) Classifications. We begin our journey in the pre-molecular era, where high-grade gliomas were divided into 'primary' and 'secondary' glioblastomas. Molecular alterations explaining these clinicopathological observations were the first branching points of glioma diagnostics, with the discovery of IDH1/2 mutations and 1p/19q codeletion. Subsequently, the rigorous characterisation of paediatric gliomas led to the unearthing of histone H3 alterations as a key event in gliomagenesis, which also had implications for young adult patients. Simultaneously, studies investigating prognostic biomarkers within tumour types were undertaken. Certain genomic phenotypes were found to portend unfavourable outcomes, for example, MYCN amplification in spinal ependymoma. The arrival of methylation profiling, having revolutionised the diagnosis of CNS tumours, now promises to bring increased prognostic accuracy, as has been shown in meningiomas. While MGMT promoter hypermethylation has remained a reliable biomarker of response to cytotoxic chemotherapy, targeted therapy in CNS tumours has unfortunately not had the success of other cancers. Therefore, predictive biomarkers have lagged behind the identification of prognostic biomarkers in CNS tumours. Emerging research from new clinical trials is cause for guarded optimism and may shift our conceptualisation of predictive biomarker testing in CNS tumours.

EZH2-interacting lncRNAs contribute to gastric tumorigenesis; a review on the mechanisms of action

Gastric cancer (GC) remains one of the deadliest malignancies worldwide, demanding new targets to improve its diagnosis and treatment. Long non-coding RNAs (lncRNAs) are dysregulated through gastric tumorigenesis and play a significant role in GC progression and development. Recent studies have revealed that lncRNAs can interact with histone-modifying polycomb protein, enhance Zeste Homolog 2 (EZH2), and mediate its site-specific functioning. EZH2, which functions as an oncogene in GC, is the catalytic subunit of the PRC2 complex that induces H3K27 trimethylation and epigenetically represses gene expression. EZH2-interacting lncRNAs can recruit EZH2 to the promoter regions of various tumor suppressor genes and cause their transcriptional deactivation via histone methylation. The interactions between EZH2 and this lncRNA modulate different processes, such as cell cycle, cell proliferation and growth, migration, invasion, metastasis, and drug resistance, in vitro and in vivo GC models. Therefore, EZH2-interacting lncRNAs are exciting targets for developing novel targeted therapies for GC. Subsequently, this review aims to focus on the roles of these interactions in GC progression to understand the therapeutic value of EZH2-interacting lncRNAs further.