Drug addiction unveils a repressive methylation ceiling in EZH2-mutant lymphoma
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ABSTRACT:
PROVIDER: PRJNA821887 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR18545500.fastq.gz | Fastqsanger.gz | |||
| SRR18545501.fastq.gz | Fastqsanger.gz | |||
| SRR18544762_1.fastq.gz | Fastqsanger.gz | |||
| SRR18544762_2.fastq.gz | Fastqsanger.gz | |||
| SRR18544763_1.fastq.gz | Fastqsanger.gz |
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Project description:Drug addiction, a phenomenon where cancer cells paradoxically depend on continuous drug treatment for survival, has uncovered cell signaling mechanisms and cancer codependencies. Here we discover mutations that confer drug addiction to inhibitors of the transcriptional repressor polycomb repressive complex 2 (PRC2) in diffuse large B-cell lymphoma. Drug addiction is mediated by hypermorphic mutations in the CXC domain of the catalytic subunit EZH2, which maintain H3K27me3 levels even in the presence of PRC2 inhibitors. Discontinuation of inhibitor treatment leads to overspreading of H3K27me3, surpassing a repressive methylation ceiling compatible with lymphoma cell survival. Exploiting this vulnerability, we show that inhibition of SETD2 similarly induces the spread of H3K27me3 and blocks lymphoma growth. Collectively, our findings demonstrate that constraints on chromatin landscapes can yield biphasic dependencies in epigenetic signaling in cancer cells. More broadly, we highlight how approaches to identify drug addiction mutations can be leveraged to discover cancer vulnerabilities.
| S-EPMC10522050 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2023-02-08 | GSE199889 | 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:Oncogenic EZH2 is overexpressed and extensively involved in the pathophysiology of different cancers including extranodal natural killer/T-cell lymphoma (NKTL). However, the mechanisms regarding EZH2 upregulation is poorly understood, and it still remains untargetable in NKTL. In this study, we examine EZH2 protein turnover in NKTL and identify MELK kinase as a regulator of EZH2 ubiquitination and turnover. Using quantitative mass spectrometry (MS) analysis, we observed a MELK-mediated increase of EZH2 S220 phosphorylation along with a concomitant loss of EZH2 K222 ubiquitination, suggesting a phosphorylation-dependent regulation of EZH2 ubiquitination. MELK inhibition through both chemical and genetic means led to ubiquitination and destabilization of EZH2 protein. Importantly, we determine that MELK is upregulated in NKTL, and its expression correlates with EZH2 protein expression as determined by tissue microarray derived from NKTL patients. Interestingly, FOXM1, which connected MELK to EZH2 signaling in glioma, was not involved in mediating EZH2 ubiquitination. Furthermore, we identify USP36 as the deubiquitinating enzyme which deubiquitinates EZH2 at K222. These findings uncover an important role of MELK and USP36 in mediating EZH2 stability in NKTL. Moreover, MELK overexpression led to decreased sensitivity to Bortezomib treatment in NKTL based on deprivation of EZH2 ubiquitination. Therefore, modulation of EZH2 ubiquitination status by targeting MELK may be a new therapeutic strategy for NKTL patients with poor Bortezomib response.
2019-08-26 | PXD015008 | Pride
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:Acquisition of drug resistance remains a chief impediment to successful cancer therapy, and we previously described a transient drug-tolerant cancer cell population (DTPs) whose survival is in part dependent on the activities of the histone methyltransferases G9a/EHMT2 and EZH2, the latter being the catalytic component of the polycomb repressive complex 2 (PRC2). Here, we applied multiple proteomic techniques to better understand the role of these HMTs in the establishment of the DTP state. Proteome-wide comparisons of lysine methylation patterns revealed that DTPs have increased methylation on K116 of PRC member Jarid2, an event that helps stabilize and recruit PRC2 to chromatin. We also found that EZH2, in addition to methylating histone H3K27, also methylates G9a at K185, and that methylated G9a better recruits repressive complexes to chromatin; similar to complexes recruited by histone H3 methylated at K9. Finally, a detailed histone posttranslational modification (PTM) analysis shows that EZH2, either directly or through its ability to methylate G9a, alters H3K9 methylation in the specific context of H3 serine10 phosphorylation, and primarily in a cancer cell subpopulation that serves as DTP precursors. We also show that combinations of histone PTMs recruit a different set of complexes to chromatin, shedding light on the temporal mechanisms that contribute to drug tolerance.
2020-01-24 | MSV000084838 | MassIVE
Project description:Background: Polycomb repressive complex 2 (PRC2) is responsible for establishing and maintaining histone H3K27 methylation during cell differentiation and proliferation. H3K27 can be mono-, di-, or tri-methylated, resulting in differential gene regulation. However, it remains unknown how PRC2 specifies the degree and biological effects of H3K27 methylation within a given cellular context. One way to determine PRC2 specificity may be through alternative splicing of Ezh2, PRC2’s catalytic subunit, during cell differentiation and tissue maturation. Results: We fully characterized the alternative splicing of Ezh2 in somatic cells and male germ cells and found that Ezh’s exon 14 was differentially regulated during mitosis and meiosis. The Ezh2 isoform containing exon 14 (ex14-Ezh2) is upregulated during cell cycle progression, consistent with a role in maintaining H3K27 methylation during chromatin replication. In contrast, the isoform lacking exon 14 (ex14D-Ezh2) was almost exclusively present in spermatocytes when new H3K27me2 is established during meiotic differentiation. Moreover, Ezh2’s transcript is normally controlled by E2F transcription activators, but in spermatocytes, Ezh2’s transcription is controlled by the meiotic regulator MYBL1. Compared to ex14-EZH2, ex14D-EZH2 has a diminished efficiency for catalyzing H3K27me3 and promotes embryonic stem cell differentiation. Conclusions: Ezh2’s expression is regulated at transcriptional and post-transcriptional levels in a cellular context-dependent manner. EZH2 variants determine functional specificity of PRC2 in histone methylation during cell proliferation and differentiation.
2018-12-01 | GSE123174 | 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
Project description:We used EZH2i-targeted hematological malignancies as an examples and focused on molecular characterization of EZH2 Y641 mutant hematological cell lines. We used the proteomic strategies and compared the protein expression level and lysine methylation level (including mono-, di-, and trimethylaiton) in EZH2 wild-type (EZH2 WT), EZH2 Y641N and Y641F (EZH2 MUT) cell lines.
2019-12-17 | PXD016779 |
Project description:Melanoma resistant to MAPK inhibitors (MAPKi) displays loss of fitness upon experimental MAPKi withdrawal and, clinically, may be resensitized to MAPKi therapy after a drug holiday. Here, we uncovered and therapeutically exploited the mechanisms of MAPKi addiction in MAPKi-resistant BRAF MUT or NRAS MUT melanoma. MAPKi-addiction phenotypes evident upon drug withdrawal spanned transient cell-cycle slowdown to cell-death responses, the latter of which required a robust phosphorylated ERK (pERK) rebound. Generally, drug withdrawal–induced pERK rebound upregulated p38–FRA1–JUNB–CDKN1A and downregulated proliferation, but only a robust pERK rebound resulted in DNA damage and parthanatos-related cell death. Importantly, pharmacologically impairing DNA damage repair during MAPKi withdrawal augmented MAPKi addiction across the board by converting a cell-cycle deceleration to a caspase-dependent cell-death response or by furthering parthanatos related cell death. Specifically in MEKi-resistant NRAS MUT or atypical BRAF MUT melanoma, treatment with a type I RAF inhibitor intensified pERK rebound elicited by MEKi withdrawal, thereby promoting a cell death–predominant MAPKi-addiction phenotype. Thus, MAPKi discontinuation upon disease progression should be coupled with specific strategies that augment MAPKi addiction.
2017-11-28 | GSE87326 | GEO