Project description:Pharmacological inhibition of the histone lysine methyltransferase EZH2 has emerged as a therapeutic strategy for the treatment of non-Hodgkin Lymphoma (NHL), in particular for cases with mono-allelic mutations in the EZH2 catalytic domain. Potent, selective EZH2 small molecule inhibitors have achieved tumor regression in mutant EZH2-containing preclinical lymphoma models and several of these inhibitors are currently engaged in cancer-focused clinical trials. Here, we show that the presence of EZH2 mutations do not always confer EZH2 inhibitor sensitivity. We discovered that EZH2 is usurped by lymphoma cells to attenuate JAK/STAT signaling and to repress pro-apoptotic interferon response genes. EZH2 inhibition results in the broad induction of interferon-stimulated genes (ISGs) in several phenotypically sensitive NHL cell models. In mutant EZH2-containing insensitive models, EZH2 inhibitors synergize specifically with type I interferons (IFNs) in vitro and in vivo to induce ISGs and apoptosis. The profound combinatorial activity of EZH2 inhibitors and type I IFNs is not restricted to NHL models with mutant EZH2 and, is preferentially observed in models that are not affected by either single agent. Molecular consequences of EZH2 inhibitor and type I IFN combinatorial treatment include STAT1 activation, binding of STAT transcription factor complexes to ISGs, reduction of H3K27me3 levels and increase of H3K4me3 levels at ISG transcriptional start sites, and ISG transcriptional activation. The molecular and anti-proliferative effects of the combination can be suppressed by inactivation of the JAK/STAT signaling pathway, by using the JAK inhibitor ruxolitinib. We suggest that EZH2 inhibitors can be therapeutically combined with type I IFNs for the treatment of NHL.
Project description:Pharmacological inhibition of the histone lysine methyltransferase EZH2 has emerged as a therapeutic strategy for the treatment of non-Hodgkin Lymphoma (NHL), in particular for cases with mono-allelic mutations in the EZH2 catalytic domain. Potent, selective EZH2 small molecule inhibitors have achieved tumor regression in mutant EZH2-containing preclinical lymphoma models and several of these inhibitors are currently engaged in cancer-focused clinical trials. Here, we show that the presence of EZH2 mutations do not always confer EZH2 inhibitor sensitivity. We discovered that EZH2 is usurped by lymphoma cells to attenuate JAK/STAT signaling and to repress pro-apoptotic interferon response genes. EZH2 inhibition results in the broad induction of interferon-stimulated genes (ISGs) in several phenotypically sensitive NHL cell models. In mutant EZH2-containing insensitive models, EZH2 inhibitors synergize specifically with type I interferons (IFNs) in vitro and in vivo to induce ISGs and apoptosis. The profound combinatorial activity of EZH2 inhibitors and type I IFNs is not restricted to NHL models with mutant EZH2 and, is preferentially observed in models that are not affected by either single agent. Molecular consequences of EZH2 inhibitor and type I IFN combinatorial treatment include STAT1 activation, binding of STAT transcription factor complexes to ISGs, reduction of H3K27me3 levels and increase of H3K4me3 levels at ISG transcriptional start sites, and ISG transcriptional activation. The molecular and anti-proliferative effects of the combination can be suppressed by inactivation of the JAK/STAT signaling pathway, by using the JAK inhibitor ruxolitinib. We suggest that EZH2 inhibitors can be therapeutically combined with type I IFNs for the treatment of NHL.
Project description:This SuperSeries is composed of the following subset Series: GSE25986: Gene expression profiling of cell lines derived from classical Hodgkin lymphoma GSE25987: Gene expression profiling of Hodgkin lymphoma cell line KMH2: Comparison of CIITA-BX648577 knockdown cultures with non-silencing controls GSE25989: Copy number analysis of Hodgkin lymphoma cell lines KM-H2 and L-428 Refer to individual Series *** This submission represents the microarray gene expression and microarray copy number components of the study
Project description:Global proteomics profiling of anaplastic large cell lymphoma cell lines DEL, SU-DHL-1 (ALK+), Mac-1, Mac-2A (ALK-) as well as Hodgkin lymphoma cell lines L-428, L-540, L-1236 and HDLM-2.
Project description:Genomewide gene expression analysis of lymphoid cell lines of Hodgkin, non-Hodgkin and acute leukemia origin Affymetrix U133 Plus 2.0 oligonucleotide arrays were hybridized to determine the gene expression profile of Hodgkin (L428, L1236, KM-H2, HDLM-2, L540, L540Cy), non-Hodgkin (Namalwa, SU-DHL-4) and acute lymphoblastic leukemia (Reh) cell lines; all hybridizations were done in biological duplicates (except L540, L50Cy, SU-DHL-4).
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:Analysis of differential gene expression in human non-Hodgkin`s lymphoma cell lines and a primary leukaemic tumor sample of large cell anaplastic type in comparison with Hodgkin`s lymphoma cell lines and other non-Hodgkin`s lymphoma samples and non-neoplastic lymphocytes Experiment Overall Design: Samples were analyzed to be compared to publically available data sets
Project description:Epigenetic mechanisms including histone modifications play key roles in the pathogenesis of multiple myeloma (MM). We have previously shown that a histone H3 lysine 27 (H3K27) methyltransferase EZH2 and a H3K9 methyltransferase G9a are potential therapeutic targets in MM. Recent studies suggested that EZH2 and G9a cooperate to regulate gene expression. We thus aimed to evaluate the anti-tumor effect by dual targeting of EZH2 and G9a in MM. A combination of an EZH2 inhibitor and a G9a inhibitor strongly suppressed myeloma cell proliferation through inducing cell cycle arrest and apoptosis in vitro. Dual inhibition of EZH2 and G9a also repressed xenograft formation by myeloma cells in vivo. Higher expression levels of EZH2 and EHMT2, which encodes G9a, are significantly associated with poorer prognosis in MM patients, respectively. Microarray analysis revealed that EZH2/G9a inhibition significantly upregulated interferon (IFN)-stimulated genes and suppressed IRF4-MYC axis genes in myeloma cells. Notably, we found increased expression and reduced H3K27/H3K9 methylation levels of endogenous retrovirus (ERV) genes in myeloma cells with the dual inhibition, suggesting that activation of the ERV genes may cause the IFN response. These results suggest that dual targeting of EZH2 and G9a may be a novel therapeutic strategy in MM.