Project description:Here we report the discovery of highly potent and selective EZH2 small molecule inhibitors, their validation by a cellular thermal shift assay, their application across a large lymphoma cell panel and their efficacy in GCBDLBCL xenograft models. RNA-seq of KARPAS-422 cell line RNA, in duplicate, treated with DMSO as control, and EZH2 inhibitors CPI360, EPZ-6438 and GSK126. Eight samples in total.
Project description:Mutations within the catalytic domain of the histone methyltransferase (HMT) EZH2 have been identified in subsets of Non-Hodgkin Lymphoma (NHL) patients. These genetic alterations are hypothesized to confer an oncogenic dependency on EZH2 enzymatic activity in these cancers. We previously reported the discovery of a potent, selective, S-adenosyl-methionine-competitive and orally bioavailable small molecule inhibitor of EZH2, EPZ-6438. EPZ-6438 selectively inhibits intracellular lysine 27 of histone H3 (H3K27) methylation in a concentration- and time-dependent manner in both EZH2 wild type and mutant lymphoma cells. Inhibition of H3K27 trimethylation (H3K27Me3) led to selective cell killing of human lymphoma cell lines bearing EZH2 catalytic domain point mutations. Treatment of xenograft-bearing mice with EPZ-6438 leads to dose-dependent tumor growth inhibition and eradication of genetically altered NHL with correlative diminution of H3K27Me3 levels in tumors and selected normal tissues. Mice dosed orally with EPZ-6438 for 28 days remained tumor free for up to 63 day after stopping compound treatment in two EZH2 mutant xenograft models. These data confirm the dependency of mutant NHL on EZH2 activity and portend the utility of EZH2-targeted drugs for the treatment of these genetically defined cancers. To identify potential biomarker and gain mechanistic insights in EPZ6438 treated lymphoma, lymphoma cell lines with or without EZH2 Y641 mutation were treated with EPZ6438 at Lowest Cytotoxic Concentration (LCC) and 10xLCC. Transcriptomes were profiled on Affemetrix U133 Plus2 chips. Differentially expressed genes and pathways upon compound treatment were anayzed. Lymphoma cell lines WSU-DLCL2, SU-DHL6, Pfeiffer, and Karpas422 were treated by EPZ6438 for 2 days, 4 days and 6 days. Treatment doses are LCC and 10xLCC of each cell lines. KARPAS_422, SUDHL6, and WSU_DLCL2 have the EZH2 Y641 mutation. PFEIFFER does not have the EZH2 Y641 mutation.
Project description:Mutations within the catalytic domain of the histone methyltransferase (HMT) EZH2 have been identified in subsets of Non-Hodgkin Lymphoma (NHL) patients. These genetic alterations are hypothesized to confer an oncogenic dependency on EZH2 enzymatic activity in these cancers. We previously reported the discovery of a potent, selective, S-adenosyl-methionine-competitive and orally bioavailable small molecule inhibitor of EZH2, EPZ-6438. EPZ-6438 selectively inhibits intracellular lysine 27 of histone H3 (H3K27) methylation in a concentration- and time-dependent manner in both EZH2 wild type and mutant lymphoma cells. Inhibition of H3K27 trimethylation (H3K27Me3) led to selective cell killing of human lymphoma cell lines bearing EZH2 catalytic domain point mutations. Treatment of xenograft-bearing mice with EPZ-6438 leads to dose-dependent tumor growth inhibition and eradication of genetically altered NHL with correlative diminution of H3K27Me3 levels in tumors and selected normal tissues. Mice dosed orally with EPZ-6438 for 28 days remained tumor free for up to 63 day after stopping compound treatment in two EZH2 mutant xenograft models. These data confirm the dependency of mutant NHL on EZH2 activity and portend the utility of EZH2-targeted drugs for the treatment of these genetically defined cancers. To identify potential biomarker and gain mechanistic insights in EPZ6438 treated lymphoma, lymphoma cell lines with or without EZH2 Y641 mutation were treated with EPZ6438 at Lowest Cytotoxic Concentration (LCC) and 10xLCC. Transcriptomes were profiled on Affemetrix U133 Plus2 chips. Differentially expressed genes and pathways upon compound treatment were anayzed.
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:Transcriptional profiles were examined in PC3 prostate cancer cells treated with vehicle (DMSO), vorinostat (VOR, HDACi), GSK126 (GSK126, EZH2i) or all 3 agents (COMBO) at 72 hours, prior to the commencement of cell death, to investigate the molecular mechamism by which these drugs and their combinations are functioning.
Project description:The Bmi1 Polycomb protein is involved in the epigenetic repressive control of self renewal and survival of cancer initiating cells. In Chronic Myeloid Leukemia (CML), bmi1 expression increases gradually as the disease progresses from a chronic latent phase to a deadly blast crisis. We developped an inducible shRNA system to silence Bmi1 in the human K562 chronic myeloid leukemia (CML) cell line in order to identify new Bmi1-target genes. Gene profiling was performed on inducible shBmi1-K562 cells incubated without (P3-K562+shBMI1) or with doxycycline for 96h (P4-K562+shBMI1+doxycycline) using HG-U133 Plus2 Affymetrix Arrays.
Project description:Using RNA-sequencing, we report the effects of overexpressing the proto-oncogene SRSF1 in K562 cells on gene expression and alternative splicing. We found that overexpressing SRSF1 antagonized the gene expression changes brought about by imatinib treatment.
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:Transcriptional profiling by array of CML CD34+ cells to understand the response of chronic myeloid leukaemia stem cells to an EZH2 inhibitor, GSK343.