HDAC1-mSin3a-NCOR1, Dnmt3b-HDAC1-Egr1 and Dnmt1-PCNA-UHRF1-G9a regulate the NY-ESO1 gene expression

Unveiling the significance of cancer-testis antigens and their implications for immunotherapy in glioma

Glioma has a poor prognosis, which is attributable to its inherent characteristics and lack of specific treatments. Immunotherapy plays a pivotal role in the contemporary management of malignancies. Despite the initiation of numerous immunotherapy-based clinical trials, their effects on enhancing glioma prognosis remain limited, highlighting the need for innovative and effective therapeutic targets and strategies to address this challenge. Since the 1990s, there has been a growing interest in cancer-testis antigens (CTAs) present in normal mammalian testicular germ cells and placental trophoblast cells, which exhibit reactivated expression in various tumor types. Mechanisms such as DNA methylation, histone modification, transcriptional regulation, and alternative splicing influence the expression of CTAs in tumors. The distinct expression patterns and robust immunogenicity of CTAs are promising tumor biomarkers and optimal targets for immunotherapy. Previous reports have shown that multiple CTAs are present in gliomas and are closely related to prognosis. The expression of these antigens is also associated with the immune response in gliomas and the effectiveness of immunotherapy. Significantly, numerous clinical trials, with IL13RA2 as a representative CTA member, have assessed the immunotherapeutic potential of gliomas and have shown favorable clinical efficacy. This review provides a comprehensive overview of the regulation and function of CTAs, summarizes their expression and role in gliomas, emphasizes their importance as immunotherapy targets in gliomas, and discusses related challenges and future interventions.

The Roles of H3K9me3 Writers, Readers, and Erasers in Cancer Immunotherapy

The interplay between cancer and the immune system has captivated researchers for a long time. Recent developments in cancer immunotherapy have substantiated this interest with a significant benefit to cancer patients. Tumor and immune cells are regulated via a wide range of molecular mechanisms involving intricate transcriptional and epigenetic networks. Epigenetic processes influence chromatin structure and accessibility, thus governing gene expression, replication, and DNA damage repair. However, aberrations within epigenetic signatures are frequently observed in cancer. One of the key epigenetic marks is the trimethylation of histone 3 at lysine 9 (H3K9me3), confined mainly within constitutive heterochromatin to suppress DNA accessibility. It is deposited at repetitive elements, centromeric and telomeric loci, as well as at the promoters of various genes. Dysregulated H3K9me3 deposition disrupts multiple pathways, including immune signaling. Consequently, altered H3K9me3 dynamics may modify the efficacy of immunotherapy. Indeed, growing evidence highlights the pivotal roles of various proteins mediating H3K9me3 deposition (SETDB1/2, SUV39H1/2), erasure (KDM3, KDM4 families, KDM7B, LSD1) and interpretation (HP1 proteins, KAP1, CHD4, CDYL, UHRF1) in modulating immunotherapy effectiveness. Here, we review the existing literature to synthesize the available information on the influence of these H3K9me3 writers, erasers, and readers on the response to immunotherapy.

NY-ESO-1 antigen: A promising frontier in cancer immunotherapy

Significant strides have been made in identifying tumour-associated antigens over the past decade, revealing unique epitopes crucial for targeted cancer therapy. Among these, the New York esophageal squamous cell carcinoma (NY-ESO-1) protein, a cancer/testis antigen, stands out. This protein is presented on the cell surface by major histocompatibility complex class I molecules and exhibits restricted expression in germline cells and various cancers, marking it as an immune-privileged site. Remarkably, NY-ESO-1 serves a dual role as both a tumour-associated antigen and its own adjuvant, implying a potential function as a damage-associated molecular pattern. It elicits strong humoural immune responses, with specific antibody frequencies significantly correlating with disease progression. These characteristics make NY-ESO-1 an appealing candidate for developing effective and specific immunotherapy, particularly for advanced stages of disease. In this review, we provide a comprehensive overview of NY-ESO-1 as an immunogenic tumour antigen. We then explore the diverse strategies for targeting NY-ESO-1, including cancer vaccination with peptides, proteins, DNA, mRNA, bacterial vectors, viral vectors, dendritic cells and artificial adjuvant vector cells, while considering the benefits and drawbacks of each strategy. Additionally, we offer an in-depth analysis of adoptive T-cell therapies, highlighting innovative techniques such as next-generation NY-ESO-1 T-cell products and the integration with lymph node-targeted vaccines to address challenges and enhance therapeutic efficacy. Overall, this comprehensive review sheds light on the evolving landscape of NY-ESO-1 targeting and its potential implications for cancer treatment, opening avenues for future tailored directions in NY-ESO-1-specific immunotherapy. HIGHLIGHTS: Endogenous immune response: NY-ESO-1 exhibited high immunogenicity, activating endogenous dendritic cells, T cells and B cells. NY-ESO-1-based cancer vaccines: NY-ESO-1 vaccines using protein/peptide, RNA/DNA, microbial vectors and artificial adjuvant vector cells have shown promise in enhancing immune responses against tumours. NY-ESO-1-specific T-cell receptor-engineered cells: NY-ESO-1-targeted T cells, along with ongoing innovations in engineered natural killer cells and other cell therapies, have improved the efficacy of immunotherapy.

Gene of the month: cancer testis antigen gene 1b (NY-ESO-1)

Cancer testis antigen gene 1B (CTAG1B) and its associated gene product; New York oesophageal squamous carcinoma 1 (NY-ESO-1), represent a unique and promising target for cancer immunotherapy. As a member of the cancer testis antigen family (CTA), the protein's restricted expression pattern and ability to elicit spontaneous humoural and cellular immune responses has resulted in a plethora of novel modalities and approaches attempting to harness its immunotherapeutic anti-cancer potential. Here, we discuss the structure and function of CTAG1B/NY-ESO-1 in both health and disease, immunohistochemical detection, as well as the most promising advances in the development of associated anti-cancer therapies. From cancer vaccines to engineered cellular therapy approaches, a multitude of immunotherapies targeting CTA's are coming to the forefront of oncology. Although the efficacy of such approaches have yet to provide convincing evidence of durable response, early phase clinical trial data has resulted in some exciting findings which will have significant potential to act as a platform for future practice changing technologies.

Distinct functions of EHMT1 and EHMT2 in cancer chemotherapy and immunotherapy

EHTM1 (GLP) and EHMT2 (G9a) are closely related protein lysine methyltransferases often thought to function together as a heterodimer to methylate histone H3 and non-histone substrates in diverse cellular processes including transcriptional regulation, genome methylation, and DNA repair. Here we show that EHMT1/2 inhibitors cause ATM-mediated slowdown of replication fork progression, accumulation of single-stranded replication gaps, emergence of cytosolic DNA, and increased expression of STING. EHMT1/2 inhibition strongly potentiates the efficacy of alkylating chemotherapy and anti-PD-1 immunotherapy in mouse models of tripe negative breast cancer. The effects on DNA replication and alkylating agent sensitivity are largely caused by the loss of EHMT1-mediated methylation of LIG1, whereas the elevated STING expression and remarkable response to immunotherapy appear mainly elicited by the loss of EHMT2 activity. Depletion of UHRF1, a protein known to be associated with EHMT1/2 and LIG1, also induces STING expression, and depletion of either EHMT2 or UHRF1 leads to demethylation of specific CpG sites in the STING1 promoter, suggestive of a distinct EHMT2-UHRF1 axis that regulates DNA methylation and gene transcription. These results highlight distinct functions of the two EHMT paralogs and provide enlightening paradigms and corresponding molecular basis for combination therapies involving alkylating agents and immune checkpoint inhibitors.

The molecular mechanisms of apoptosis accompanied with the epigenetic regulation of the NY-ESO-1 antigen in non-small lung cancer cells treated with decitabine (5-aza-CdR)

Dysregulated epigenetic modifications are common in lung cancer but have been reversed using demethylating agent like 5-Aza-CdR. 5-Aza-CdR induces/upregulates the NY-ESO-1 antigen in lung cancer. Therefore, we investigated the molecular mechanisms accompanied with the epigenetic regulation of NY-ESO-1 in 5-Aza-CdR-treated NCI-H1975 cell line. We showed significant induction of the NY-ESO-1 protein (**p < 0.0097) using Cellular ELISA. Bisulfite-sequencing demonstrated 45.6% demethylation efficiency at the NY-ESO-1 gene promoter region and RT-qPCR analysis confirmed the significant induction of NY-ESO-1 at mRNA level (128-fold increase, *p < 0.050). We then investigated the mechanism by which 5-Aza-CdR inhibits cell proliferation in the NCI-H1975 cell line. Upregulation of the death receptors TRAIL (2.04-fold *p < 0.011) and FAS (2.1-fold *p < 0.011) indicate activation of the extrinsic apoptotic pathway. The upregulation of Voltage-dependent anion-selective channel protein 1 (1.9-fold), Major vault protein (1.8-fold), Bax (1.16-fold), and Cytochrome C (1.39-fold) indicate the activation of the intrinsic pathway. We also observed the differential expression of protein Complement C3 (3.3-fold), Destrin (-5.1-fold), Vimentin (-1.7-fold), Peroxiredoxin 4 (-1.6-fold), Fascin (-1.8-fold), Heme oxygenase-2 (-0.67-fold**p < 0.0055), Hsp27 (-0.57-fold**p < 0.004), and Hsp70 (-0.39-fold **p < 0.001), indicating reduced cell growth, cell migration, and metastasis. The upregulation of 40S ribosomal protein S9 (3-fold), 40S ribosomal protein S15 (4.2-fold), 40S ribosomal protein S18 (2.5-fold), and 60S ribosomal protein L22 (4.4-fold) implied the induction of translation machinery. These results reiterate the decisive role of 5-Aza-CdR in lung cancer treatment since it induces the epigenetic regulation of NY-ESO-1 antigen, inhibits cell proliferation, increases apoptosis, and decreases invasiveness.

Epigenetic and Transcriptomic Programming of HSC Quiescence Signaling in Large for Gestational Age Neonates

Excessive fetal growth is associated with DNA methylation alterations in human hematopoietic stem and progenitor cells (HSPC), but their functional impact remains elusive. We implemented an integrative analysis combining single-cell epigenomics, single-cell transcriptomics, and in vitro analyses to functionally link DNA methylation changes to putative alterations of HSPC functions. We showed in hematopoietic stem cells (HSC) from large for gestational age neonates that both DNA hypermethylation and chromatin rearrangements target a specific network of transcription factors known to sustain stem cell quiescence. In parallel, we found a decreased expression of key genes regulating HSC differentiation including EGR1, KLF2, SOCS3, and JUNB. Our functional analyses showed that this epigenetic programming was associated with a decreased ability for HSCs to remain quiescent. Taken together, our multimodal approach using single-cell (epi)genomics showed that human fetal overgrowth affects hematopoietic stem cells' quiescence signaling via epigenetic programming.

HDAC Inhibition for Optimized Cellular Immunotherapy of NY-ESO-1-Positive Soft Tissue Sarcoma

Adoptive cell therapy with NY-ESO-1-specific T cells is a promising option for the treatment of soft tissue sarcoma (STS) but achieves only transient tumor control in the majority of cases. A strategy to optimize this cell therapeutic approach might be the modulation of the expression of the cancer-testis antigen NY-ESO-1 using histone deacetylase inhibitors (HDACis). In this study, the ex vivo effect of combining NY-ESO-1-specific T cells with the clinically approved pan HDACis panobinostat or vorionstat was investigated. Our data demonstrated that STS cells were sensitive to HDACis. Administration of HDACi prior to NY-ESO-1-specific T cells exerted enhanced lysis against the NY-ESO-1+ STS cell line SW982. This correlated with an increase in the NY-ESO-1 and HLA-ABC expression of SW982 cells, as well as increased CD25 expression on NY-ESO-1-specific T cells. Furthermore, the immune reactivity of NY-ESO-1-specific CD8+ T cells in terms of cytokine release was enhanced by HDACis. In summary, pretreatment with HDACis represents a potential means of enhancing the cytotoxic efficacy of NY-ESO-1-specific T cells against NY-ESO-1-positive STS.

Cancer immunotherapy using artificial adjuvant vector cells to deliver NY-ESO-1 antigen to dendritic cells in situ

NY‐ESO‐1 is a cancer/testis antigen expressed in various cancer types. However, the induction of NY‐ESO‐1‐specific CTLs through vaccines is somewhat difficult. Thus, we developed a new type of artificial adjuvant vector cell (aAVC‐NY‐ESO‐1) expressing a CD1d‐NKT cell ligand complex and a tumor‐associated antigen, NY‐ESO‐1. First, we determined the activation of invariant natural killer T (iNKT) and natural killer (NK) cell responses by aAVC‐NY‐ESO‐1. We then showed that the NY‐ESO‐1‐specific CTL response was successfully elicited through aAVC‐NY‐ESO‐1 therapy. After injection of aAVC‐NY‐ESO‐1, we found that dendritic cells (DCs) in situ expressed high levels of costimulatory molecules and produced interleukn‐12 (IL‐12), indicating that DCs undergo maturation in vivo. Furthermore, the NY‐ESO‐1 antigen from aAVC‐NY‐ESO‐1 was delivered to the DCs in vivo, and it was presented on MHC class I molecules. The cross‐presentation of the NY‐ESO‐1 antigen was absent in conventional DC‐deficient mice, suggesting a host DC‐mediated CTL response. Thus, this strategy helps generate sufficient CD8⁺ NY‐ESO‐1‐specific CTLs along with iNKT and NK cell activation, resulting in a strong antitumor effect. Furthermore, we established a human DC‐transferred NOD/Shi‐scid/IL‐2γc^null immunodeficient mouse model and showed that the NY‐ESO‐1 antigen from aAVC‐NY‐ESO‐1 was cross‐presented to antigen‐specific CTLs through human DCs. Taken together, these data suggest that aAVC‐NY‐ESO‐1 has potential for harnessing innate and adaptive immunity against NY‐ESO‐1‐expressing malignancies.

Reduced NCOR2 expression accelerates androgen deprivation therapy failure in prostate cancer

This study addresses the roles of nuclear receptor corepressor 2 (NCOR2) in prostate cancer (PC) progression in response to androgen deprivation therapy (ADT). Reduced NCOR2 expression significantly associates with shorter disease-free survival in patients with PC receiving adjuvant ADT. Utilizing the CWR22 xenograft model, we demonstrate that stably reduced NCOR2 expression accelerates disease recurrence following ADT, associates with gene expression patterns that include neuroendocrine features, and induces DNA hypermethylation. Stably reduced NCOR2 expression in isogenic LNCaP (androgen-sensitive) and LNCaP-C4–2 (androgen-independent) cells revealed that NCOR2 reduction phenocopies the impact of androgen treatment and induces global DNA hypermethylation patterns. NCOR2 genomic binding is greatest in LNCaP-C4–2 cells and most clearly associates with forkhead box (FOX) transcription factor FOXA1 binding. NCOR2 binding significantly associates with transcriptional regulation most when in active enhancer regions. These studies reveal robust roles for NCOR2 in regulating the PC transcriptome and epigenome and underscore recent mutational studies linking NCOR2 loss of function to PC disease progression.

Long et al. show that reduced levels of NCOR2 lead to accelerated prostate cancer recurrence during androgen withdrawal in a patient-derived xenograft model. NCOR2 reduction is characterized by incomplete response to androgen withdrawal, and recurrent tumors show increased neuroendocrine traits. These phenotypic changes are associated with hypermethylated enhancers.

Misregulation of the expression and activity of DNA methyltransferases in cancer

In mammals, DNA methyltransferases DNMT1 and DNMT3's (A, B and L) deposit and maintain DNA methylation in dividing and nondividing cells. Although these enzymes have an unremarkable DNA sequence specificity (CpG), their regional specificity is regulated by interactions with various protein factors, chromatin modifiers, and post-translational modifications of histones. Changes in the DNMT expression or interacting partners affect DNA methylation patterns. Consequently, the acquired gene expression may increase the proliferative potential of cells, often concomitant with loss of cell identity as found in cancer. Aberrant DNA methylation, including hypermethylation and hypomethylation at various genomic regions, therefore, is a hallmark of most cancers. Additionally, somatic mutations in DNMTs that affect catalytic activity were mapped in Acute Myeloid Leukemia cancer cells. Despite being very effective in some cancers, the clinically approved DNMT inhibitors lack specificity, which could result in a wide range of deleterious effects. Elucidating distinct molecular mechanisms of DNMTs will facilitate the discovery of alternative cancer therapeutic targets. This review is focused on: (i) the structure and characteristics of DNMTs, (ii) the prevalence of mutations and abnormal expression of DNMTs in cancer, (iii) factors that mediate their abnormal expression and (iv) the effect of anomalous DNMT-complexes in cancer.

EHMT2/G9a as an Epigenetic Target in Pediatric and Adult Brain Tumors

Epigenetic mechanisms, including post-translational modifications of DNA and histones that influence chromatin structure, regulate gene expression during normal development and are also involved in carcinogenesis and cancer progression. The histone methyltransferase G9a (euchromatic histone lysine methyltransferase 2, EHMT2), which mostly mediates mono- and dimethylation by histone H3 lysine 9 (H3K9), influences gene expression involved in embryonic development and tissue differentiation. Overexpression of G9a has been observed in several cancer types, and different classes of G9a inhibitors have been developed as potential anticancer agents. Here, we review the emerging evidence suggesting the involvement of changes in G9a activity in brain tumors, namely glioblastoma (GBM), the main type of primary malignant brain cancer in adults, and medulloblastoma (MB), the most common type of malignant brain cancer in children. We also discuss the role of G9a in neuroblastoma (NB) and the drug development of G9a inhibitors.

Egr‑1 inhibits colon cancer cell proliferation, migration and invasion via regulating CDKL1 at the transcriptional level

Colon cancer is one of the most common malignant tumors worldwide, and the molecular mechanisms involved in the oncogenesis and progression of colon cancer remain unclear. Early growth response 1 (Egr‑1) is a transcription factor that is closely associated with several tumor processes; however, its role in colon cancer is unknown. The present study aimed to explore the function and mechanism of transcription factor Egr‑1 in colon cancer progression. The association between Egr‑1 expression and the survival of patients with colon cancer was analyzed. Transwell assay was used to measure the migration and invasion of colon cancer cells. Cell Counting Kit‑8 assay was used to evaluate the cell proliferative ability. Reverse transcription‑quantitative PCR and western blot assays were used to identify whether Egr‑1 could regulate cyclin‑dependent kinase‑like 1 (CDKL1). Luciferase and chromatin immunoprecipitation assays were used to detect the mechanism by which Egr‑1 regulated CDKL1. Based on The Cancer Genome Atlas database, it was found that low Egr‑1 expression was associated with a poor prognosis in patients with colon cancer. Furthermore, overexpression of Egr‑1 inhibited colon cancer cell proliferation, migration, and invasion, whereas knockdown of Egr‑1 increased colon cancer cell proliferation, migration and invasion. Additionally, overexpression of Egr‑1‑induced cell proliferation, migration and invasion were reversed by overexpression of CDKL1. Furthermore, it was demonstrated that Egr‑1 regulated CDKL1 expression at the transcriptional level. The present study illustrated the mechanism of Egr‑1 regulating CDKL1, by which Egr‑1 affected colon cancer cell proliferation, migration and invasion. The current findings suggested that Egr‑1/CDKL1 may be a new promising target for the treatment of colon cancer.

DNA Methylation as a Diagnostic Biomarker for Malignant Mesothelioma: A Systematic Review and Meta-Analysis

Malignant mesothelioma is an aggressive cancer type linked to asbestos exposure. Because of several intrinsic challenges, mesothelioma is often diagnosed in an advanced disease stage. Therefore, there is a need for diagnostic biomarkers that may contribute to early detection. Recently, the epigenome of tumors is being extensively investigated to identify biomarkers. This manuscript is a systematic review summarizing the state-of-the-art research investigating DNA methylation in mesothelioma. Four literature databases (PubMed, Scopus, Web of Science, MEDLINE) were systematically searched for studies investigating DNA methylation in mesothelioma up to October 16, 2020. A meta-analysis was performed per gene investigated in at least two independent studies. A total of 53 studies investigated DNA methylation of 97 genes in mesothelioma and are described in a qualitative overview. Furthermore, ten studies investigating 13 genes (APC, CDH1, CDKN2A, DAPK, ESR1, MGMT, miR-34b/c, PGR, RARβ, RASSF1, SFRP1, SFRP4, WIF1) were included in the quantitative meta-analysis. In this meta-analysis, the APC gene is significantly hypomethylated in mesothelioma, whereas CDH1, ESR1, miR-34b/c, PGR, RARβ, SFRP1, and WIF1 are significantly hypermethylated in mesothelioma. The three genes that are the most appropriate candidate biomarkers from this meta-analysis are APC, miR-34b/c, and WIF1. Nevertheless, both study number and study objects comprised in this meta-analysis are too low to draw final conclusions on their clinical applications. The elucidation of the genome-wide DNA methylation profile of mesothelioma is desirable in the future, using a standardized genome-wide methylation analysis approach. The most informative CpG sites from this signature could then form the basis of a panel of highly sensitive and specific biomarkers that can be used for the diagnosis of mesothelioma and even for the screening of an at high-risk population of asbestos-exposed individuals.

Oncogenic cancer/testis antigens are a hallmarker of cancer and a sensible target for cancer immunotherapy

Increasing evidence shows that numerous cancer-testis antigens (CTAs) are uniquely overexpressed in various types of cancer and most CTAs are oncogenic. Overexpression of oncogenic CTAs promotes carcinogenesis, cancer metastasis, and drug resistance. Oncogenic CTAs are generally associated with poor prognosis in cancer patients and are an important hallmark of cancer, making them a crucial target for cancer immunotherapy. CTAs-targeted antibodies, vaccines, and chimeric antigen receptor-modified T cells (CAR-T) have recently been used in cancer treatment and achieved promising outcomes in the preclinical and early clinical trials. However, the efficacy of current CTA-targeted therapeutics is either moderate or low in cancer therapy. CTA-targeted cancer immunotherapy is facing enormous challenges. Several critical scientific problems need to be resolved: (1) the antigen presentation function of MHC-I protein is usually deficient in cancer patients, so that very low amounts of intracellular CTA epitopes are presented to tumor cell membrane surface, leading to weak immune response and subsequent immunity to CTAs; (2) various immunosuppressive cells are rich in tumor tissues leading to diminished tumor immunity; (3) the tumor tissue microenvironment markedly reduces the efficacy of cancer immunotherapy. In the current review paper, the authors propose new strategies and approaches to overcome the barriers of CTAs-targeted immunotherapy and to develop novel potent immune therapeutics against cancer. Finally, we highlight that the oncogenic CTAs have high tumor specificity and immunogenicity, and are sensible targets for cancer immunotherapy. We predict that CTAs-targeted immunotherapy will bring about breakthroughs in cancer therapy in the near future.

Combined Analysis of RNA Sequence and Microarray Data Reveals a Competing Endogenous RNA Network as Novel Prognostic Markers in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a highly aggressive cancer with short survival time. Unbalanced competing endogenous RNAs (ceRNAs) have been shown to participate in the tumor pathogenesis and served as biomarkers for the clinical prognosis. However, the comprehensive analyses of the ceRNA network in the prognosis of MPM are still rarely reported. In this study, we obtained the transcriptome data of the MPM and the normal samples from TCGA, EGA, and GEO databases and identified the differentially expressed (DE) mRNAs, lncRNAs, and miRNAs. The functions of the prognostic genes and the overlapped DEmRNAs were further annotated by the multiple enrichment analyses. Then, the targeting relationships among lncRNA–miRNA and miRNA–mRNA were predicted and calculated, and a prognostic ceRNA regulatory network was established. We included the prognostic 73 mRNAs and 13 miRNAs and 26 lncRNAs into the ceRNA network. Moreover, 33 mRNAs, three miRNAs, and seven lncRNAs were finally associated with prognosis, and a model including seven mRNAs, two lincRNAs, and some clinical factors was finally established and validated by two independent cohorts, where CDK6 and SGMS1-AS1 were significant to be independent prognostic factors. In addition, the identified co-expressed modules associated with the prognosis were overrepresented in the ceRNA network. Multiple enrichment analyses showed the important roles of the extracellular matrix components and cell division dysfunction in the invasion of MPM potentially. In summary, the prognostic ceRNA network of MPM was established and analyzed for the first time and these findings shed light on the function of ceRNAs and revealed the potential prognostic and therapeutic biomarkers of MPM.

Thymoquinone Is a Multitarget Single Epidrug That Inhibits the UHRF1 Protein Complex

Silencing of tumor suppressor genes (TSGs) through epigenetic mechanisms, mainly via abnormal promoter DNA methylation, is considered a main mechanism of tumorigenesis. The abnormal DNA methylation profiles are transmitted from the cancer mother cell to the daughter cells through the involvement of a macromolecular complex in which the ubiquitin-like containing plant homeodomain (PHD), and an interesting new gene (RING) finger domains 1 (UHRF1), play the role of conductor. Indeed, UHRF1 interacts with epigenetic writers, such as DNA methyltransferase 1 (DNMT1), histone methyltransferase G9a, erasers like histone deacetylase 1 (HDAC1), and functions as a hub protein. Thus, targeting UHRF1 and/or its partners is a promising strategy for epigenetic cancer therapy. The natural compound thymoquinone (TQ) exhibits anticancer activities by targeting several cellular signaling pathways, including those involving UHRF1. In this review, we highlight TQ as a potential multitarget single epidrug that functions by targeting the UHRF1/DNMT1/HDAC1/G9a complex. We also speculate on the possibility that TQ might specifically target UHRF1, with subsequent regulatory effects on other partners.

DNMT1 as a therapeutic target in pancreatic cancer: mechanisms and clinical implications

BACKGROUND

Pancreatic cancer or pancreatic ductal adenocarcinoma (PDAC) is one of the most devastating cancer types with a 5-year survival rate of only 9%. PDAC is one of the leading causes of cancer-related deaths in both genders. Epigenetic alterations may lead to the suppression of tumor suppressor genes, and DNA methylation is a predominant epigenetic modification. DNA methyltransferase 1 (DNMT1) is required for maintaining patterns of DNA methylation during cellular replication. Accumulating evidence has implicated the oncogenic roles of DNMT1 in various malignancies including PDACs.

CONCLUSIONS

Herein, the expression profiles, oncogenic roles, regulators and inhibitors of DNMT1 in PDACs are presented and discussed. DNMT1 is overexpressed in PDAC cases compared with non-cancerous pancreatic ducts, and its expression gradually increases from pre-neoplastic lesions to PDACs. DNMT1 plays oncogenic roles in suppressing PDAC cell differentiation and in promoting their proliferation, migration and invasion, as well as in induction of the self-renewal capacity of PDAC cancer stem cells. These effects are achieved via promoter hypermethylation of tumor suppressor genes, including cyclin-dependent kinase inhibitors (e.g., p14, p15, p16, p21 and p27), suppressors of epithelial-mesenchymal transition (e.g., E-cadherin) and tumor suppressor miRNAs (e.g., miR-148a, miR-152 and miR-17-92 cluster). Pre-clinical investigations have shown the potency of novel non-nucleoside DNMT1 inhibitors against PDAC cells. Finally, phase I/II clinical trials of DNMT1 inhibitors (azacitidine, decitabine and guadecitabine) in PDAC patients are currently underway, where these inhibitors have the potential to sensitize PDACs to chemotherapy and immune checkpoint blockade therapy.

DNMT1: A key drug target in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. Altered epigenetics regulation including DNA hypermethylation by DNA methyltransferase 1 (DNMT1) has been implicated as one of the causes of TNBC tumorigenesis. In this review, the oncogenic functions rendered by DNMT1 in TNBCs, and DNMT1 inhibitors targeting TNBC cells are presented and discussed. In summary, DNMT1 expression is associated with poor breast cancer survival, and it is overexpressed in TNBC subtype. The oncogenic roles of DNMT1 in TNBCs include: (1) Repression of estrogen receptor (ER) expression; (2) Promotion of epithelial-mesenchymal transition (EMT) required for metastasis; (3) Induces cellular autophagy and; (4) Promotes the growth of cancer stem cells in TNBCs. DNMT1 confers these phenotypes by hypermethylating the promoter regions of ER, multiple tumor suppressor genes, microRNAs and epithelial markers involved in suppressing EMT. DNMT1 inhibitors exert anti-tumorigenic effects against TNBC cells. This includes the hypomethylating agents azacitidine, decitabine and guadecitabine that might sensitize TNBC patients to immune checkpoint blockade therapy. DNMT1 represents an epigenetic target for TNBC cells destruction as well as to derail their metastatic and aggressive phenotypes.

Unleashing the immune response to NY-ESO-1 cancer testis antigen as a potential target for cancer immunotherapy

INTRODUCTION

Cancer Immunotherapy has recently emerged as a promising and effective modality to treat different malignancies. Antigenic profiling of cancer tissues and determination of any pre-existing immune responses to cancer antigens may help predict responses to immune intervention in cancer. NY-ESO-1, a cancer testis antigen is the most immunogenic antigen to date. The promise of NY-ESO-1 as a candidate for specific immune recognition of cancer comes from its restricted expression in normal adult tissue but frequent occurrence in multiple tumors including melanoma and carcinomas of lung, esophageal, liver, gastric, prostrate, ovarian, and bladder.

MAIN BODY

This review summarizes current knowledge of NY-ESO-1 as efficient biomarker and target of immunotherapy. It also addresses limitations and challenges preventing a robust immune response to NY-ESO-1 expressing cancers, and describes pre-clinical and clinical observations relevant to NY-ESO-1 immunity, holding potential therapeutic relevance for cancer treatment.

CONCLUSION

NY-ESO-1 induces strong immune responses in cancer patients but has limited objective clinical responses to NY-ESO-1 expressing tumors due to effect of competitive negative signaling from immune-checkpoints and immune-suppressive tumor microenvironment. We propose that combination therapy to increase the efficacy of NY-ESO-1 specific immunotherapeutic interventions should be explored to unleash the immune response against NY-ESO-1 expressing tumors.

Targeting Epigenetic Dependencies in Solid Tumors: Evolutionary Landscape Beyond Germ Layers Origin

Extensive efforts recently witnessed the complexity of cancer biology; however, molecular medicine still lacks the ability to elucidate hidden mechanisms for the maintenance of specific subclasses of rare tumors characterized by the silent onset and a poor prognosis (e.g., ovarian cancer, pancreatic cancer, and glioblastoma). Recent mutational fingerprints of human cancers highlighted genomic alteration occurring on epigenetic modulators. In this scenario, the epigenome dependency of cancer orchestrates a broad range of cellular processes critical for tumorigenesis and tumor progression, possibly mediating escaping mechanisms leading to drug resistance. Indeed, in this review, we discuss the pivotal role of chromatin remodeling in shaping the tumor architecture and modulating tumor fitness in a microenvironment-dependent context. We will also present recent advances in the epigenome targeting, posing a particular emphasis on how this knowledge could be translated into a feasible therapeutic approach to individualize clinical settings and improve patient outcomes.

Selective Inhibition of HDAC1 by Macrocyclic Polypeptide for the Treatment of Glioblastoma: A Binding Mechanistic Analysis Based on Molecular Dynamics

Glioblastoma (GBM) is the most common and aggressive intracranial malignant brain tumor, and the abnormal expression of HDAC1 is closely correlated to the progression, recurrence and metastasis of GBM cells, making selective inhibition of HDAC1 a promising strategy for GBM treatments. Among all available selective HDAC1 inhibitors, the macrocyclic peptides have gained great attention due to their remarkable inhibitory selectivity on HDAC1. However, the binding mechanism underlying this selectivity is still elusive, which increases the difficulty of designing and synthesizing the macrocyclic peptide-based anti-GBM drug. Herein, multiple computational approaches were employed to explore the binding behaviors of a typical macrocyclic peptide FK228 in both HDAC1 and HDAC6. Starting from the docking conformations of FK228 in the binding pockets of HDAC1&6, relatively long MD simulation (500 ns) shown that the hydrophobic interaction and hydrogen bonding of E91 and D92 in the Loop2 of HDAC1 with the Cap had a certain traction effect on FK228, and the sub-pocket formed by Loop1 and Loop2 in HDAC1 could better accommodate the Cap group, which had a positive effect on maintaining the active conformation of FK228. While the weakening of the interactions between FK228 and the residues in the Loop2 of HDAC6 during the MD simulation led to the large deflection of FK228 in the binding site, which also resulted in the decrease in the interactions between the Linker region of FK228 and the previously identified key amino acids (H134, F143, H174, and F203). Therefore, the residues located in Loop1 and Loop2 contributed in maintaining the active conformation of FK228, which would provide valuable hints for the discovery and design of novel macrocyclic polypeptide HDAC inhibitors.

UHRF1 promotes renal cell carcinoma progression through epigenetic regulation of TXNIP

UHRF1 is an important epigenetic regulator that belongs to the UHRF family. Overexpression of UHRF1 has been found in many kinds of tumors and its overexpression is associated with poor prognosis and short survival in certain cancer types. However, its function in renal cell carcinoma (RCC) is not clear. Here we report that RCC tumor tissues had obviously higher UHRF1 expression than normal renal tissues. Downregulation of UHRF1 by siRNA or shRNA in RCC cell lines resulted in decreased cell viability, inhibited cell migration and invasion, and increased apoptosis. UHRF1 knockdown RCC xenografts also resulted in obviously inhibited tumor growth in vivo. After downregulation of UHRF1 in RCC cells, the expression of TXNIP was upregulated. In addition, after UHRF1 and TXNIP were simultaneously downregulated, cell viability and cell invasion increased, whereas cell apoptosis decreased compared with UHRF1 single downregulated cells. We also showed that UHRF1 could recruit HDAC1 to the TXNIP promoter and mediate the deacetylation of histone H3K9, resulting in the inhibition of TXNIP expression. Our results confirm that UHRF1 has oncogenic function in RCC and UHRF1 may promote tumor progression through epigenetic regulation of TXNIP. UHRF1 might be used as a therapeutic target for RCC treatment.

Epigenetic mechanism and target therapy of UHRF1 protein complex in malignancies

Ubiquitin-like with plant homeodomain and really interesting new gene finger domains 1 (UHRF1) functions as an epigenetic regulator recruiting PCNA, DNMT1, histone deacetylase 1, G9a, SuV39H, herpes virus-associated ubiquitin-specific protease, and Tat-interactive protein by multiple corresponding domains of DNA and H3 to maintain DNA methylation and histone modifications. Overexpression of UHRF1 has been found as a potential biomarker in various cancers resulting in either DNA hypermethylation or global DNA hypo-methylation, which participates in the occurrence, progression, and invasion of cancer. The role of UHRF1 in the reciprocal interaction between DNA methylation and histone modifications, the dynamic structural transformation of UHRF1 protein within epigenetic code replication machinery in epigenetic regulations, as well as modifications during cell cycle and chemotherapy targeting UHRF1 are evaluated in this study.

Assessment of new HDAC inhibitors for immunotherapy of malignant pleural mesothelioma

Background

Malignant pleural mesothelioma (MPM) is a very rare and highly aggressive cancer of the pleura associated in most cases with asbestos exposure. To date, no really efficient treatments are available for this pathology. Recently, it has been shown that epigenetic drugs, particularly DNA methylation or histone acetylation modulating agents, could be very efficient in terms of cytotoxicity for several types of cancer cells. We previously showed that a hypomethylating agent (decitabine) and a histone deacetylase inhibitor (HDACi) (valproic acid (VPA)) combination was immunogenic and led to the induction of an anti-tumor immune response in a mice model of mesothelioma. However, VPA is not very specific, is active at millimolar concentrations and is responsible for side effects in clinic. To improve this approach, we studied four newly synthetized HDACi, two hydroxamates (ODH and NODH) and two benzamides (ODB and NODB), in comparison with VPA and SAHA. We evaluated their toxicity on immune cells and their immunogenicity on MPM cells in combination with decitabine.

Results

All the tested HDACi were toxic for immune cells at high concentrations. Combination with decitabine increased toxicity of HDACi only towards T-cell clone. A decrease in the proportion of regulatory T cells and natural killer cells was observed in particular with VPA and ODH. In MPM cells, all HDACi combinations induced NY-ESO-1 cancer testis antigen (CTA) expression and the recognition of the treated cells by a NY-ESO-1 specific T-CD8 clone. However, for MAGE-A1, MAGE-A3 and XAGE-1b mRNA expression, the results obtained depended on the HDACi used and on the CTA studied. Depending on the MPM cell line studied, molecules alone increased moderately PD-L1 expression. When combined, a higher stimulation of this immune check point inhibitor expression was observed. Decitabine-induced anti-viral response seemed to be inhibited in the presence of HDACi.

Conclusions

This work shows that the combination of decitabine and HDACi could be of interest for MPM immunotherapy. However, this combination induced PD-L1 expression which suggests that an association with anti-PD-L1 therapy should be performed to induce an efficient anti-tumor immune response.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0517-9) contains supplementary material, which is available to authorized users.

Ablation of toll-like receptor 4 attenuates aging-induced myocardial remodeling and contractile dysfunction through NCoRI-HDAC1-mediated regulation of autophagy

Aging is usually accompanied with overt structural and functional changes as well as suppressed autophagy in the heart although the precise regulatory mechanisms are somewhat unknown. Here we evaluated the role of the innate proinflammatory mediator toll-like receptor 4 (TLR4) in cardiac aging and the underlying mechanism with a focus on autophagy. Cardiac geometry and function were monitored in young or old wild-type (WT) and TLR4 knockout (TLR4^-/-) mice using echocardiography, IonOptix® edge-detection and fura-2 techniques. Levels of autophagy and mitophagy, nuclear receptor corepressor 1 (NCoR1) and histone deacetylase I (HDAC1) were examined using western blot. Transmission electronic microscopy (TEM) was employed to monitor myocardial ultrastructure. Our results revealed that TLR4 ablation alleviated advanced aging (24 months)-induced changes in myocardial remodeling (increased heart weight, chamber size, cardiomyocyte cross-sectional area), contractile function and intracellular Ca²⁺ handling as well as autophagy and mitophagy [Beclin-1, Atg5, LC3B, PTEN-induced putative kinase 1 (PINK1), Parkin and p62]. Aging downregulated levels of NCoR1 and HDAC1 as well as their interaction, the effects were significantly attenuated or negated by TLR4 ablation. Advanced aging disturbed myocardial ultrastructure as evidenced by loss of myofilament alignment and swollen mitochondria, which was obliterated by TLR4 ablation. Moreover, aging suppressed autophagy (GFP-LC3B puncta) in neonatal mouse cardiomyocytes, the effect of which was negated by the TLR4 inhibitor CLI-095. Inhibition of HDCA1 using apicidin cancelled off CLI095-induced beneficial response of GFP-LC3B puncta against aging. Our data collectively indicate a role for TLR4-mediated autophagy in cardiac remodeling and contractile dysfunction in aging through a HDAC1-NCoR1-dependent mechanism.

Class IIa histone deacetylases link cAMP signaling to the myelin transcriptional program of Schwann cells

Schwann cells respond to cyclic adenosine monophosphate (cAMP) halting proliferation and expressing myelin proteins. Here we show that cAMP signaling induces the nuclear shuttling of the class IIa histone deacetylase (HDAC)-4 in these cells, where it binds to the promoter and blocks the expression of c-Jun, a negative regulator of myelination. To do it, HDAC4 does not interfere with the transcriptional activity of MEF2. Instead, by interacting with NCoR1, it recruits HDAC3 and deacetylates histone 3 in the promoter of c-Jun, blocking gene expression. Importantly, this is enough to up-regulate Krox20 and start Schwann cell differentiation program-inducing myelin gene expression. Using conditional knockout mice, we also show that HDAC4 together with HDAC5 redundantly contribute to activate the myelin transcriptional program and the development of myelin sheath in vivo. We propose a model in which cAMP signaling shuttles class IIa HDACs into the nucleus of Schwann cells to regulate the initial steps of myelination in the peripheral nervous system.

Specific or not specific recruitment of DNMTs for DNA methylation, an epigenetic dilemma

Our current view of DNA methylation processes is strongly moving: First, even if it was generally admitted that DNMT3A and DNMT3B are associated with de novo methylation and DNMT1 is associated with inheritance DNA methylation, these distinctions are now not so clear. Secondly, since one decade, many partners of DNMTs have been involved in both the regulation of DNA methylation activity and DNMT recruitment on DNA. The high diversity of interactions and the combination of these interactions let us to subclass the different DNMT-including complexes. For example, the DNMT3L/DNMT3A complex is mainly related to de novo DNA methylation in embryonic states, whereas the DNMT1/PCNA/UHRF1 complex is required for maintaining global DNA methylation following DNA replication. On the opposite to these unspecific DNA methylation machineries (no preferential DNA sequence), some recently identified DNMT-including complexes are recruited on specific DNA sequences. The coexistence of both types of DNA methylation (un/specific) suggests a close cooperation and an orchestration between these systems to maintain genome and epigenome integrities. Deregulation of these systems can lead to pathologic disorders.

Targeting the epigenome in malignant pleural mesothelioma

Malignant pleural mesotheliomas (MPM) are notoriously refractory to conventional treatment modalities. Recent insights regarding epigenetic alterations in MPM provide the preclinical rationale for the evaluation of novel combinatorial regimens targeting the epigenome in these neoplasms.

Epi-drugs in combination with immunotherapy: a new avenue to improve anticancer efficacy

Immune checkpoint factors, such as programmed cell death protein-1/2 (PD-1, PD-2) or cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) receptors, are targets for monoclonal antibodies (MAbs) developed for cancer immunotherapy. Indeed, modulating immune inhibitory pathways has been considered an important breakthrough in cancer treatment. Although immune checkpoint blockade therapy used to treat malignant diseases has provided promising results, both solid and haematological malignancies develop mechanisms that enable themselves to evade the host immune system. To overcome some major limitations and ensure safety in patients, recent strategies have shown that combining epigenetic modulators, such as inhibitors of histone deacetylases (HDACi) or DNA methyltransferases (DNMTi), with immunotherapeutics can be useful. Preclinical data generated using mouse models strongly support the feasibility and effectiveness of the proposed approaches. Indeed, co-treatment with pan- or class I-selective HDACi or DNMTi improved beneficial outcomes in both in vitro and in vivo studies. Based on the evidence of a pivotal role for HDACi and DNMTi in modulating various components belonging to the immune system, recent clinical trials have shown that both HDACi and DNMTi strongly augmented response to anti-PD-1 immunotherapy in different tumour types. This review describes the current strategies to increase immunotherapy responses, the effects of HDACi and DNMTi on immune modulation, and the advantages of combinatorial therapy over single-drug treatment.

HDAC Inhibitor-Induced Mitotic Arrest Is Mediated by Eg5/KIF11 Acetylation

Histone deacetylase 1 (HDAC1) is an epigenetic enzyme that regulates key cellular processes, such as cell proliferation, apoptosis, and cell survival, by deacetylating histone substrates. Aberrant expression of HDAC1 is implicated in multiple diseases, including cancer. As a consequence, HDAC inhibitors have emerged as effective anti-cancer drugs. HDAC inhibitor-induced G₀/G₁ cell-cycle arrest has been attributed to epigenetic transcriptional changes mediated by histone acetylation. However, the mechanism of G₂/M arrest remains poorly understood. Here, we identified mitosis-related protein Eg5 (KIF11) as an HDAC1 substrate using a trapping mutant strategy. HDAC1 colocalized with Eg5 during mitosis and influenced the ATPase activity of Eg5. Importantly, an HDAC1- and HDAC2-selective inhibitor caused mitotic arrest and monopolar spindle formation, consistent with a model in which Eg5 deacetylation by HDAC1 is critical for mitotic progression. These findings revealed a previously unknown mechanism of action of HDAC inhibitors involving Eg5 acetylation, and provide a compelling mechanistic hypothesis for HDAC inhibitor-mediated G₂/M arrest.

New York esophageal squamous cell carcinoma-1 and cancer immunotherapy

New York esophageal squamous cell carcinoma 1 (NY-ESO-1) is a known cancer testis gene with exceptional immunogenicity and prevalent expression in many cancer types. These characteristics have made it an appropriate vaccine candidate with the potential application against various malignancies. This article reviews recent knowledge about the NY-ESO-1 biology, function, immunogenicity and expression in cancers as well as and the results of clinical trials with this antigen.

The autophagy GABARAPL1 gene is epigenetically regulated in breast cancer models

Background

The GABARAP family members (GABARAP, GABARAPL1/GEC1 and GABARAPL2 /GATE-16) are involved in the intracellular transport of receptors and the autophagy pathway. We previously reported that GABARAPL1 expression was frequently downregulated in cancer cells while a high GABARAPL1 expression is a good prognosis marker for patients with lymph node-positive breast cancer.

Methods

In this study, we asked using qRT-PCR, western blotting and epigenetic quantification whether the expression of the GABARAP family was regulated in breast cancer by epigenetic modifications.

Results

Our data demonstrated that a specific decrease of GABARAPL1 expression in breast cancers was associated with both DNA methylation and histone deacetylation and that CREB-1 recruitment on GABARAPL1 promoter was required for GABARAPL1 expression.

Conclusions

Our work strongly suggests that epigenetic inhibitors and CREB-1 modulators may be used in the future to regulate autophagy in breast cancer cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1761-4) contains supplementary material, which is available to authorized users.

Computational genomic analysis of PARK7 interactome reveals high BBS1 gene expression as a prognostic factor favoring survival in malignant pleural mesothelioma

The aim of our study was to assess the differential gene expression of Parkinson protein 7 (PARK7) interactome in malignant pleural mesothelioma (MPM) using data mining techniques to identify novel candidate genes that may play a role in the pathogenicity of MPM. We constructed the PARK7 interactome using the ConsensusPathDB database. We then interrogated the Oncomine Cancer Microarray database using the Gordon Mesothelioma Study, for differential gene expression of the PARK7 interactome. In ConsensusPathDB, 38 protein interactors of PARK7 were identified. In the Gordon Mesothelioma Study, 34 of them were assessed out of which SUMO1, UBC3, KIAA0101, HDAC2, DAXX, RBBP4, BBS1, NONO, RBBP7, HTRA2, and STUB1 were significantly overexpressed whereas TRAF6 and MTA2 were significantly underexpressed in MPM patients (network 2). Furthermore, Kaplan-Meier analysis revealed that MPM patients with high BBS1 expression had a median overall survival of 16.5 vs. 8.7 mo of those that had low expression. For validation purposes, we performed a meta-analysis in Oncomine database in five sarcoma datasets. Eight network 2 genes (KIAA0101, HDAC2, SUMO1, RBBP4, NONO, RBBP7, HTRA2, and MTA2) were significantly differentially expressed in an array of 18 different sarcoma types. Finally, Gene Ontology annotation enrichment analysis revealed significant roles of the PARK7 interactome in NuRD, CHD, and SWI/SNF protein complexes. In conclusion, we identified 13 novel genes differentially expressed in MPM, never reported before. Among them, BBS1 emerged as a novel predictor of overall survival in MPM. Finally, we identified that PARK7 interactome is involved in novel pathways pertinent in MPM disease.

DNA methyltransferases 3a and 3b are differentially expressed in the early stages of a rat liver carcinogenesis model

Carcinogenesis is driven by the accumulation of mutations and abnormal DNA methylation patterns, particularly the hypermethylation of tumor‑suppressor genes. Changes in genomic DNA methylation patterns are established by the DNA methyltransferases (DNMTs) family: DNMT1, DNMT3a and DNMT3b. The DNMTs are known to be overexpressed in tumors. However, when the DNMTs expression profile is altered in earlier stages of carcinogenesis remains to be elucidated. The resistant hepatocyte model (RHM) allows the analysis of the hepatocellular carcinoma (HCC) from the formation of altered cell foci to the appearance of tumors in rats. To investigate the DNMTs expression in this model, we first observed that timp3, rassf1a and p16 genes became methylated during cancer development by methylation‑specific PCR (MSP) and the bisulphate sequencing PCR (BSP) of timp3. The differential expression at the RNA and protein level of the three DNMTs was also assessed. dnmt1 expression was higher in tumors than in normal and early cancer stages. However, no evident overexpression of the enzyme was identified by immunohistochemistry. By contrast, DNMT3a and DNMT3b were consistently subexpressed in tumors. In the present study, we report a carcinogenesis model that does not feature the overexpression of DNMT1 but exhibits a transient expression of DNMT3a and DNMT3b.

Perinatal α-linolenic acid availability alters the expression of genes related to memory and to epigenetic machinery, and the Mecp2 DNA methylation in the whole brain of mouse offspring

Many animal and human studies indicated that dietary ω-3 fatty acids could have beneficial roles on brain development, memory, and learning. However, the exact mechanisms involved are far from being clearly understood, especially for α-linolenic acid (ALA), which is the precursor for the ω-3 elongation and desaturation pathways. This study investigated the alterations induced by different intakes of flaxseed oil (containing 50% ALA), during gestation and lactation, upon the expression of genes involved in neurogenesis, memory-related molecular processes, and DNA methylation, in the brains of mouse offspring at the end of lactation (postnatal day 19, P19). In addition, DNA methylation status for the same genes was investigated. Maternal flaxseed oil supplementation during lactation increased the expression of Mecp2, Ppp1cc, and Reelin, while decreasing the expression of Ppp1cb and Dnmt3a. Dnmt1 expression was decreased by postnatal flaxseed oil supplementation but this effect was offset by ALA deficiency during gestation. Mecp2 DNA methylation was decreased by maternal ALA deficiency during gestation, with a more robust effect in the lactation-deficient group. In addition, linear regression analysis revealed positive correlations between Mecp2, Reelin, and Ppp1cc, between Gadd45b, Bdnf, and Creb1, and between Egr1 and Dnmt1, respectively. However, there were no correlations, in any gene, between DNA methylation and gene expression. In summary, the interplay between ALA availability during gestation and lactation differentially altered the expression of genes involved in neurogenesis and memory, in the whole brain of the offspring at the end of lactation. The Mecp2 epigenetic status was correlated with ALA availability during gestation. However, the epigenetic status of the genes investigated was not associated with transcript levels, suggesting that either the regulation of these genes is not necessarily under epigenetic control, or that the whole brain model is not adequate for the exploration of epigenetic regulation in the context of this study.

Identification of a large protein network involved in epigenetic transmission in replicating DNA of embryonic stem cells

Pluripotency of embryonic stem cells (ESCs) is maintained by transcriptional activities and chromatin modifying complexes highly organized within the chromatin. Although much effort has been focused on identifying genome-binding sites, little is known on their dynamic association with chromatin across cell divisions. Here, we used a modified version of the iPOND (isolation of proteins at nascent DNA) technology to identify a large protein network enriched at nascent DNA in ESCs. This comprehensive and unbiased proteomic characterization in ESCs reveals that, in addition to the core replication machinery, proteins relevant for pluripotency of ESCs are present at DNA replication sites. In particular, we show that the chromatin remodeller HDAC1–NuRD complex is enriched at nascent DNA. Interestingly, an acute block of HDAC1 in ESCs leads to increased acetylation of histone H3 lysine 9 at nascent DNA together with a concomitant loss of methylation. Consistently, in contrast to what has been described in tumour cell lines, these chromatin marks were found to be stable during cell cycle progression of ESCs. Our results are therefore compatible with a rapid deacetylation-coupled methylation mechanism during the replication of DNA in ESCs that may participate in the preservation of pluripotency of ESCs during replication.

Exemestane blocks mesothelioma growth through downregulation of cAMP, pCREB and CD44 implicating new treatment option in patients affected by this disease

Background

Recent evidence suggests that aromatase may be involved in the pathogenesis of malignant mesothelioma. Here, we evaluated the effect of exemestane, an inhibitor of aromatase, in the treatment of mesothelioma using in vitro and in vivo preclinical models.

Results

We show a significant reduction of cell proliferation, survival, migration and block of cells in S phase of cell cycle in mesothelioma cells upon exemestane treatment. Moreover, we find that CD44, which is involved in mesothelioma cells migration, was modulated by exemestane via cAMP and pCREB. Most importantly, in mice mesothelioma xenograft exemestane causes a significant decrease in tumor size and the association pemetrexed/exemestane is more effective than pemetrexed/cisplatin.

Conclusion

The preclinical mesothelioma model suggests that exemestane might be beneficial in mesothelioma treatment.

HDAC1-mSin3a-NCOR1, Dnmt3b-HDAC1-Egr1 and Dnmt1-PCNA-UHRF1-G9a regulate the NY-ESO1 gene expression

The NY-ESO1 gene is a cancer/testis antigen considered to be suitable target for the immunotherapy of human malignancies. Despite the identification of the epigenetical silencing of the NY-ESO1 gene in a large variety of tumors, the molecular mechanism involved in this phenomenon is not fully elucidated. In two non epithelial cancers (glioma and mesothelioma), we found that the epigenetic regulation of the NY-ESO1 gene requires the sequential recruitment of the HDAC1-mSin3a-NCOR, Dnmt3b-HDAC1-Egr1 and Dnmt1-PCNA-UHRF1-G9a complexes. Thus, our data illustrate the orchestration of a sequential epigenetic mechanism including the histone deacetylation and methylation, and the DNA methylation processes.