The effect of Ezh2 knockdown in high-grade glioma
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE63853 | GEO | 2015/03/20
SECONDARY ACCESSION(S): PRJNA269257
REPOSITORIES: GEO
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Project description:Diffuse Intrinsic Pontine Glioma (DIPG) is a rare and highly aggressive pediatric tumor. The average survival time after diagnosis is less than one year. Currently, there are no effective treatments. Characteristic of DIPG is a mutation in histone H3 which leads to a substitution of Lysine 27 to Methionine (H3K27M) which deregulates Polycomb Repressive Complex 2 (PRC2), including enzymatic activity of EZH2. Previous studies have shown that inhibition of EZH2 by chemical agents decreases DIPG cell proliferation and inhibits tumor growth in vivo. My thesis project aims to confirm that EZH2 could be a therapeutic target using chemical EZH2 inhibitors, small interfering RNAs and a CRISPR/Cas9 approach in a series of DIPG tumor cell lines and to determine underlying molecular mechanisms of action.
2022-04-01 | PXD017525 | Pride
Project description:Pediatric high-grade gliomas, specifically diffuse intrinsic pontine gliomas (DIPG), account for 20% of clinical cases but have a 100% fatality rate. A majority of DIPG cases are characterized by the signature H3K27M mutation that is predicted to oppose EZH2, the methyltransferase enzyme of the Polycomb Repressor Complex 2 (PRC2). However, a clear understanding of EZH2’s role in DIPG is lacking. In this study, by incorporating Ezh2 loss and gain of function into our DIPG mouse models we demonstrate its tumor suppressor function. Genetic ablation of Ezh2 increased cell proliferation and tumor grade while expression of an Ezh2 gain of function mutation significantly reduced tumor incidence, increased tumor latency. Transcriptomic analysis revealed that EZH2 deletion upregulates an inflammatory response with upregulation of immunoproteasome genes such as Psmb8, Psmb9, and Psmb10 while EZH2 deletion an enrichment of the oxidative phosphorylation/mitochondrial metabolic pathway namely the isocitrate dehydrogenase Idh1/2/3 genes. Pharmacological inhibition of EZH2 augmented neural progenitor cell proliferation, supporting the tumor suppressive role of EZH2. In vivo treatment of DIPG tumor bearing Ntv-a;p53fl/fl; abcb1a-/-; abcb1b-/-; abcg2-/- (ABC knockout, ABC KO) mice with EZH2 inhibitor, EPZ-6438 did not alter proliferation or significantly impact survival. Together our results suggest that EZH2 has a tumor suppressor function in DIPG and warrants caution in clinical translation of these inhibitors to treat patients with DIPG.
2022-01-01 | GSE188450 | GEO
Project description:Overexpression of EZH2 in estrogen receptor negative (ER-) breast cancer promotes metastasis. EZH2 has been mainly studied as the catalytic component of the Polycomb Repressive Complex 2 (PRC2) that mediates gene repression by trimethylating histone H3 at lysine 27 (H3K27me3). However, how EZH2 drives metastasis despite the low H3K27me3 levels observed in ER- breast cancer is unknown. We have shown that in human invasive carcinomas and distant metastases, cytoplasmic EZH2 phosphorylated at T367 is significantly associated with ER- disease and low H3K27me3 levels. Here, we explore the interactome of EZH2 and of a phosphodeficient mutant EZH2_T367A. We identified novel interactors of EZH2, and identified interactions that are dependent on the phosphorylation and cellular localization of EZH2 that may play a role in EZH2 dependent metastatic progression.
2018-07-03 | PXD010073 | Pride
Project description:Change of gene expression profile by EZH2 silencing EZH2 is overexpressed in a number of malignancies, and is an attractive target for cancer treatment. The overexpression of EZH2 was significantly associated with disease free survival and overall survival of patients with ovarian cancer. EZH2 silencing resulted in decreased cell viability and invasion ability, and increased apoptosis. EZH2 silencing significantly enhanced cytotoxicity of paclitaxel, docetaxel and cisplatin in Hec-1A and Ishikawa cells. EZH2 silencing using siRNA incorporated into chitosan nanoparticles (siRNA/CH) resulted in significant inhibition of tumor growth compared to control siRNA/CH. Moreover, EZH2 siRNA/CH in combination with taxanes showed robust anti-tumor effects compared to monotherapy groups. These effects were associated with decreased tumor cell proliferation and angiogenesis, and increased tumor cell apoptosis. Genomic analyses revealed that EZH2 gene silencing resulted in decreased expression of many genes associated with tumor growth.
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Project description:The aim of this study was to identify EZH2 targets in myeloid malignancies. RNA samples from control F-36P, MOLM-13 and OCI-M2 cells (secondary AML after MDS; EZH2 wild type) treated with random shRNA (n = 4, each) and test F-36P, MOLM-13 and OCI-M2 cells treated with either one of two EZH2-targeting shRNAs (n = 4, each) were screened for differential gene expression. RNA from EZH2 wild type (n = 12) and mutant (n = 12) MDS/MPN patients was also analyzed by microarray transcriptome analysis.
2017-06-15 | E-MTAB-5766 | biostudies-arrayexpress
Project description:Efforts to therapeutically target EZH2 have generally focused on inhibition of its methyltransferase activity, although it remains less clear whether this is the central mechanism whereby EZH2 promotes cancer. We demonstrate that EZH2 directly interacts with both MYC family oncoproteins, MYC and MYCN, and promotes their stabilization in a methyltransferase-independent manner. By competing against the SCFFBW7 ubiquitin ligase to bind MYC and MYCN, EZH2 counteracted FBW7-mediated MYC(N) polyubiquitination and proteasomal degradation. Depletion, but not enzymatic inhibition, of EZH2 induced robust MYC(N) degradation and inhibited tumor cell growth in MYC(N) driven neuroblastoma and small cell lung cancer. These findings unveil the MYC family proteins as global EZH2 oncogenic effectors and EZH2 pharmacologic degraders as potential MYC(N) targeted cancer therapeutics, pointing out that MYC(N) driven cancers may develop inherent resistance to the canonical EZH2 enzymatic inhibitors currently in clinical development.
2022-02-17 | PXD029652 | Pride
Project description:Purpose: Increasing evidence suggests that epigenetic reprogramming contributes significantly to the development of endocrine therapy resistance in breast cancer. The goal of this work is to explore how the histone methyltransferase EZH2 interacts with ER signaling and drives the insensitiveness of breast cancer cells to the antagonistic effect of tamoxifen on ER activity. Therefore, we comprehensively analyzed the transcriptional program regulated by EZH2 in tamoxifen-resistant (TamR) MCF-7 cells. Methods: TamR MCF-7 cells between passage 142-144 upon were used for this assay. For mRNA-Seq, cells are transfected with scrambled control shRNAs (shCtrl) or shRNAs targeting EZH2 (shEZH2). Total RNA were extracted by TRIzol (Invitrogen) and libraries were constructed using Illumina TruSeq RNA Sample Prep Kit v2 (Cat.# RS-122-2001). Hiseq 3000 was used for sequencing.
2017-12-01 | GSE92316 | GEO
Project description:The Enhancer of Zeste 2 Polycomb Repressive Complex 2 Subunit (EZH2) is an essential epigenetic modifier able to methylate lysine 27 on histone H3 (H3K27) to induce chromatin compaction, protein complex recruitment and ultimately transcriptional repression. Hematologic malignancies, including Diffuse Large B cell lymphoma (DLBCL) and Acute myeloid leukemia (AML) have shown a high EZH2-mutation frequency (>20%) associated with poor clinical outcomes. Particularly, two distinct oncogenic mutations, so-called gain-of-function (Y641F and A677G) and loss-of-function (H689A and F667I) are found in the catalytic domain of EZH2. In this study, a comprehensive multi-omics approach was employed to characterize downstream effects of H3K27me3 deposition driven by EZH2 mutations. Human embryonic kidney cells (HEK293T) were transfected to generate three stable EZH2 mutants: EZH2(Y641F), EZH2(A677G), and EZH2(H689A/F667I), which were validated via immunoblotting and DIA-MS-based histone profiling assay. Subsequently, constructs were analyzed under a comprehensive multi-omics approach including label-free whole-cell proteomics, acquired with a Bruker timsTOF Pro HPLC-MS/MS with Ion Mobility. Important protein interactors at nuclear level were dysregulated, such as SMYD3 (SET and MYND domain containing 3), NSD2 (nuclear receptor binding SET domain protein 2) and CHD7 (chromodomain helicase DNA binding protein 7), suggesting a cooperative network of chromatin remodelers for gene expression reprogramming.
2023-10-24 | PXD042875 | Pride
Project description:Background: Previous studies have shown that EZH2 regulates tumor PD-L1 expression at the transcriptional level and has an impact on tumor immune environment and prognosis. However, whether EZH2 can regulate PD-L1 expression at the post-translational level remains unclear. Therefore, this study aims to investigate the effects of EZH2 inhibition on PD-L1 expression and protein stability in colorectal cancer cells, uncover its underlying mechanisms, and provide new therapeutic strategies for anti-tumor immune therapy. Methods: Multiple colorectal cancer cell models were used to examine the effects of EZH2 inhibition on PD-L1 expression and protein stability at both the protein and transcriptional levels. Transcriptome analysis was performed to identify differentially expressed genes associated with EZH2 inhibition and potential effectors involved in EZH2-mediated regulation of PD-L1 protein stability. Validation of candidate genes was conducted through public database analysis and knockdown or overexpression models. Finally, the combined effects of EZH2 inhibitors and anti-PD-1 immune therapy were evaluated using a mouse xenograft model. Results: We observed that inhibition of EZH2 function upregulated PD-L1 expression and enhanced its protein stability in colorectal cancer cells. Transcriptome analysis revealed that ubiquitin-specific protease 22 (USP22) played a crucial role in mediating EZH2-regulated PD-L1 protein stability. EZH2 affected USP22 expression through its classical epigenetic regulatory function, thereby modulating PD-L1 expression stability and influencing the tumor immune microenvironment. Combination treatment with EZH2 inhibitors and anti-PD-1 immune therapy improved the tumor microenvironment, promoted immune cell infiltration, and exerted synergistic anti-cancer effects. Conclusion: This study elucidated the mechanisms by EZH2 regulate PD-L1 expression and stability, providing new insights into therapeutic strategies for colorectal cancer. The combination of EZH2 inhibitors and anti-PD-1 immune therapy can synergistically enhance anti-tumor effects. These findings offer a potential therapeutic approach to improve the effectiveness of EZH2 inhibitors in cancer treatment and contribute to a better understanding of the role of EZH2 in tumor immune regulation.
2024-07-01 | GSE243955 | GEO
Project description:The Enhancer of Zeste 2 Polycomb Repressive Complex 2 Subunit (EZH2) is an essential epigenetic modifier able to methylate lysine 27 on histone H3 (H3K27) to induce chromatin compaction, protein complex recruitment and ultimately transcriptional repression. Hematologic malignancies, including Diffuse Large B cell lymphoma (DLBCL) and Acute myeloid leukemia (AML) have shown a high EZH2-mutation frequency (>20%) associated with poor clinical outcomes. Particularly, two distinct oncogenic mutations, so-called gain-of-function (Y641F and A677G) and loss-of-function (H689A and F667I) are found in the catalytic domain of EZH2. In this study, a comprehensive multi-omics approach was employed to characterize downstream effects of H3K27me3 deposition driven by EZH2 mutations. Human embryonic kidney cells (HEK293T) were transfected to generate three stable EZH2 mutants: EZH2(Y641F), EZH2(A677G), and EZH2(H689A/F667I), which were validated via immunoblotting and DIA-MS-based histone profiling assay. The histone profiling assay demonstrated a significant increase of approximately two-fold in H3.1/H3.3K27me3 for Y641F EZH2 mutant. There was a modest increase in the combinatorial PTMs H3.1/H3.3K27me3K36me1 and a significant depletion in H3.1 and H3.3 K27me2. The most depleted peptide was H3.3K27me2K36me2. For the A677G EZH2 mutant, the assay demonstrated an enrichment on H3.1/H3.3K27me3, combinatorial K27me3K36me1 and a slight increase in K27me1 and K18ac but only on H3.1. The most depleted peptide was H3.3K27me2K36me2. The H689A/F667I cell line has the most alterations in global histone PTMs. The most highly enriched were H3.1/H3.3K36me2, H3.1K9me3 and H3.3K36me1. The most depleted modifications were H3.1K23ac and H3.1K27me3.
2023-10-24 | PXD042953 | Pride