Project description:This SuperSeries is composed of the following subset Series: GSE40970: ChIP-seq analysis of H3K27me3 histone modification in EZH2 mutant and wild type DLBCL cell lines GSE40971: Gene expression profiling of EZH2 mutant and wild type DLBCL cell lines treated with EZH2 inhibitor GSE41239: Gene expression profiling of two DLBCL cell lines upon shRNA mediated knockdown of EZH2 Refer to individual Series
Project description:We studied transcriptional changes by Affymetrix human microarrays in DLBCL cell lines as a result of treatment with GSK126, a potent, highly-selective, SAM-competitive, small molecule inhibitor of EZH2 In eukaryotes, epigenetic post-translational modification of histones is critical for regulation of chromatin structure and gene expression. EZH2 is the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) and is responsible for repressing target gene expression through methylation of histone H3 on lysine 27 (H3K27). Over-expression of EZH2 is implicated in tumorigenesis and correlates with poor prognosis in multiple tumor types. Recent reports have identified somatic heterozygous mutations of Y641 and A677 residues within the catalytic SET domain of EZH2 in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). The Y641 residue is the most frequently mutated residue, with 22% of GCB (Germinal Cell B-cell) DLBCL and FL harboring mutations at this site. These lymphomas exhibit increased H3K27 tri-methylation (H3K27me3) due to altered substrate preferences of the mutant enzymes. However, it is unknown whether direct inhibition of EZH2 methyltransferase activity alone will be effective in treating lymphomas carrying activating EZH2 mutations. Herein, we demonstrate that GSK126, a potent, highly-selective, SAM-competitive, small molecule inhibitor of EZH2 methyltransferase activity, decreases global H3K27me3 levels and reactivates silenced PRC2 target genes. GSK126 effectively inhibits the proliferation of EZH2 mutant DLBCL cell lines and dramatically inhibits the growth of EZH2 mutant DLBCL xenografts in mice. Together, these data demonstrate that pharmacological inhibition of EZH2 activity may provide a promising treatment for EZH2 mutant lymphoma. 10 DLBCL cell lines (7 mutant and 3 wild type EZH2), that were differentially sensitive to GSK126 in proliferation assays, were treated for 72 hours, in duplicate (n=2), with either DMSO (vehicle) or 500nM of GSK126, a potent selective EZH2 inhibitor. EZH2 mutant cell lines are Pfeiffer, KARPAS-422, WSU-DLCL2, SU-DHL-10, SU-DHL-6, DB and SU-DHL-4. EZH2 wildtype cell lines are HT, OCI-LY-19 and Toledo.
Project description:Background: Upregulation of H3K27me3 induced by EZH2 overexpression or somatic heterozygous mutations were implicated in lymphomagenesis. It has been demonstrated that several EZH2-target agents have notable therapeutic effects in EZH2-mutant B-cell lymphoma patients. Here we present a novel highly selective EZH2 inhibitor SHR2554 and possible combination strategy in diffuse large B cell lymphoma (DLBCL); Methods: Cell proliferation, cycle and apoptosis were analyzed by Cell Titer-Glo Luminescent Cell Viability Assay and flow cytometry. Western Blot was used to detect the regulatory protease in related signaling pathways and RNA-seq was conducted to assess transcriptome changes. Finally, CDX and PDX models were used to evaluate the synergistic anti-tumor effects of the combination in vivo; Results: The novel EZH2 inhibitor SHR2554 could inhibited proliferation, induced G1 phase arrest in EZH2-mutant DLBCL cell lines. The combination of EZH2 inhibitor SHR2554 with histone deacetylase (HDAC) inhibitor chidamide (hereafter referred as HBI8000) exerted synergistic anti-proliferative activity in vitro and in vivo. Gene expression profile analysis revealed dramatic inhibition of DNA replication process in combined treatment; Conclusions: SHR2554, a potent highly selective small molecule inhibitor of EZH2, inhibited EZH2-mutant DLBCL more significantly in vitro and in vivo. The combination of HDAC inhibitor HBI8000 with EZH2 inhibitor SHR2554 exhibited dramatically anti-tumor activity in both mutant and wild-type DLBCL, which may become potential therapeutic modality for the treatment of DLBCL patients.
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.
Project description:We studied transcriptional changes by Affymetrix human microarrays in 2 DLBCL cell lines as a result of shRNA mediated knockdown of EZH2. In eukaryotes, epigenetic post-translational modification of histones is critical for regulation of chromatin structure and gene expression. EZH2 is the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) and is responsible for repressing target gene expression through methylation of histone H3 on lysine 27 (H3K27). Over-expression of EZH2 is implicated in tumorigenesis and correlates with poor prognosis in multiple tumor types. Recent reports have identified somatic heterozygous mutations of Y641 and A677 residues within the catalytic SET domain of EZH2 in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). The Y641 residue is the most frequently mutated residue, with 22% of GCB (Germinal Cell B-cell) DLBCL and FL harboring mutations at this site. These lymphomas exhibit increased H3K27 tri-methylation (H3K27me3) due to altered substrate preferences of the mutant enzymes. However, it is unknown whether direct inhibition of EZH2 methyltransferase activity alone will be effective in treating lymphomas carrying activating EZH2 mutations. Herein, we demonstrate that GSK126, a potent, highly-selective, SAM-competitive, small molecule inhibitor of EZH2 methyltransferase activity, decreases global H3K27me3 levels and reactivates silenced PRC2 target genes. GSK126 effectively inhibits the proliferation of EZH2 mutant DLBCL cell lines and dramatically inhibits the growth of EZH2 mutant DLBCL xenografts in mice. Together, these data demonstrate that pharmacological inhibition of EZH2 activity may provide a promising treatment for EZH2 mutant lymphoma. Pfeiffer and KARPAS-422 cells were treated with either shRNA targeting EZH2 (shEZH2) or a non targeting control (shNTC) for 10 days.
Project description:We studied transcriptional changes by Affymetrix human microarrays in DLBCL cell lines as a result of treatment with GSK126, a potent, highly-selective, SAM-competitive, small molecule inhibitor of EZH2 In eukaryotes, epigenetic post-translational modification of histones is critical for regulation of chromatin structure and gene expression. EZH2 is the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) and is responsible for repressing target gene expression through methylation of histone H3 on lysine 27 (H3K27). Over-expression of EZH2 is implicated in tumorigenesis and correlates with poor prognosis in multiple tumor types. Recent reports have identified somatic heterozygous mutations of Y641 and A677 residues within the catalytic SET domain of EZH2 in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). The Y641 residue is the most frequently mutated residue, with 22% of GCB (Germinal Cell B-cell) DLBCL and FL harboring mutations at this site. These lymphomas exhibit increased H3K27 tri-methylation (H3K27me3) due to altered substrate preferences of the mutant enzymes. However, it is unknown whether direct inhibition of EZH2 methyltransferase activity alone will be effective in treating lymphomas carrying activating EZH2 mutations. Herein, we demonstrate that GSK126, a potent, highly-selective, SAM-competitive, small molecule inhibitor of EZH2 methyltransferase activity, decreases global H3K27me3 levels and reactivates silenced PRC2 target genes. GSK126 effectively inhibits the proliferation of EZH2 mutant DLBCL cell lines and dramatically inhibits the growth of EZH2 mutant DLBCL xenografts in mice. Together, these data demonstrate that pharmacological inhibition of EZH2 activity may provide a promising treatment for EZH2 mutant lymphoma.
Project description:In eukaryotes, epigenetic post-translational modification of histones is critical for regulation of chromatin structure and gene expression. EZH2 is the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) and is responsible for repressing target gene expression through methylation of histone H3 on lysine 27 (H3K27). Over-expression of EZH2 is implicated in tumorigenesis and correlates with poor prognosis in multiple tumor types. Recent reports have identified somatic heterozygous mutations of Y641 and A677 residues within the catalytic SET domain of EZH2 in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). The Y641 residue is the most frequently mutated residue, with 22% of GCB (Germinal centre B-cell) DLBCL and FL harboring mutations at this site. These lymphomas exhibit increased H3K27 tri-methylation (H3K27me3) due to altered substrate preferences of the mutant enzymes. However, it is unknown whether direct inhibition of EZH2 methyltransferase activity alone will be effective in treating lymphomas carrying activating EZH2 mutations. Herein, we demonstrate that GSK126, a potent, highly-selective, SAM-competitive, small molecule inhibitor of EZH2 methyltransferase activity, decreases global H3K27me3 levels and reactivates silenced PRC2 target genes. GSK126 effectively inhibits the proliferation of EZH2 mutant DLBCL cell lines and dramatically inhibits the growth of EZH2 mutant DLBCL xenografts in mice. Together, these data demonstrate that pharmacological inhibition of EZH2 activity may provide a promising treatment for EZH2 mutant lymphoma. We performed a ChIP-seq experiment to understand the genomewide pattern of H3K27me3 enrichment in DLBCL cell lines that were differentially sensitive to GSK126. H3K27me3 bound chromatin and input controls was immunoprecipitated and subjected to sequencing on the Illumina GA Iix. In total, 3 cell lines were profiled - 3 EZH2 mutant (Pfeiffer, KARPAS-422, WSU-DLCL2).
Project description:We studied transcriptional changes by Affymetrix human microarrays in 2 DLBCL cell lines as a result of shRNA mediated knockdown of EZH2. In eukaryotes, epigenetic post-translational modification of histones is critical for regulation of chromatin structure and gene expression. EZH2 is the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) and is responsible for repressing target gene expression through methylation of histone H3 on lysine 27 (H3K27). Over-expression of EZH2 is implicated in tumorigenesis and correlates with poor prognosis in multiple tumor types. Recent reports have identified somatic heterozygous mutations of Y641 and A677 residues within the catalytic SET domain of EZH2 in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). The Y641 residue is the most frequently mutated residue, with 22% of GCB (Germinal Cell B-cell) DLBCL and FL harboring mutations at this site. These lymphomas exhibit increased H3K27 tri-methylation (H3K27me3) due to altered substrate preferences of the mutant enzymes. However, it is unknown whether direct inhibition of EZH2 methyltransferase activity alone will be effective in treating lymphomas carrying activating EZH2 mutations. Herein, we demonstrate that GSK126, a potent, highly-selective, SAM-competitive, small molecule inhibitor of EZH2 methyltransferase activity, decreases global H3K27me3 levels and reactivates silenced PRC2 target genes. GSK126 effectively inhibits the proliferation of EZH2 mutant DLBCL cell lines and dramatically inhibits the growth of EZH2 mutant DLBCL xenografts in mice. Together, these data demonstrate that pharmacological inhibition of EZH2 activity may provide a promising treatment for EZH2 mutant lymphoma.
Project description:EZH2 mediates the humoral immune response and drives lymphomagenesis through de novo formation of bivalent chromatin domains and critical germinal center (GC) B cell promoters. We show that such formation is dependent on the presense of BCL6 and the presence of non-canonical PRC1-BCOR complex. We observe that BCL6 and EZH2 cooperate to accelerate diffuse large B cell lymphoma (DLBCL) development and combinatorial targeting of these repressors results in enhanced anti-lymphoma activity in vitro, in vivo, and in primary human DLBCLs. DLBCL cell lines treated with BCL6 inhibitor 79-6.1085