Project description:Treatment of the acute T cell leukemia cell line Jurkat in vitro with the most potent histone deacetylase inhibitor, Trichostatin A induced apoptosis in a dose-dependent manner. Analysis of the drug-treated Jurkat cells using high throughput genome-wide gene expression profiling indicated the upregulation as well as downregulation of several genes crucial for cellular functions. Use of quantitative reverse transcriptase-mediated polymerase chain reaction validated the regulation of selected genes in drug-treated cells. Collectively, this study has unraveled the genes involved in epigenetic regulation of the T cell leukemia. Microarray analysis was performed to determine the changes in global gene expression profiles during apoptosis of a T cell leukemia induced by the histone deacetylase inhibitor, Trichostatin A. Drug treatment induced the upregulation and repression of a number of genes.
Project description:Large biological heterogeneity hallmarks acute myeloid leukemia (AML) and substantially hampers development of novel comprehensive therapies. While all-trans retinoic acid (ATRA) revolutionized therapy of acute promyelocytic leukemia, its impact on other AML subtypes remained largely disappointing. Here we show for the first time that ATRA mediated phosphorylation of the histone demethylase PHF8 induces apoptosis of AML cells of different subtypes via regulation of viral mimicry and subsequent initiation of interferon (IFN) type-I response. Phospho-PHF8 conferred H3K9me2 demethylation at promoter sites of key initiators of cell-intrinsic immune response. Multiomics based analyses revealed activation of cytosolic RNA sensors as key step towards NF-κB driven IFN type-I mediated apoptosis. Epigenetic changes directed by PHF8 also induced a specific proteosome pathway controlling NF-κB activity after its initial activation. Hence, PHF8 orchestrates viral mimicry, triggering IFN type-I response-differentiation-apoptotic network in a broad spectrum of AML when activated by ATRA. Forced phosphorylation of PHF8 via combination treatment with ATRA and simultaneous pharmacological inhibition of PHF8 dephosphorylation significantly impaired growth of human AML. Our findings finally open the gate for successful application of ATRA-based combination therapies in AML.
Project description:Transcriptional deregulation plays a major role in acute myeloid leukemia, identification of epigenetic modifying enzymes essential for the maintenance of oncogenic transcription programs holds the key to better understanding the biology and designing effective therapeutic strategies for the disease. Here we provide experimental evidence showing the functional involvement and therapeutic potentials of targeting PRMT1 with H4R3 methyltransferase activity in various MLL and non-MLL leukemias. PRMT1 is necessary but not sufficient for leukemic transformation, which requires co-recruitment of KDM4C with H3K9 demethylase activity by chimeric transcription factors to mediate epigenetic reprogramming. Inhibition of KDM4C/PRMT1 suppresses transcription and transformation ability of MLL fusions and MOZ-TIF2, revealing a novel and targetable epigenetic circuitry mediated by PRMT1 and KDM4C in acute leukemia.
Project description:Relapse of acute myeloid leukemia (AML) is highly aggressive and often treatment refractory. We analyzed previously published AML relapse cohorts and found that 40% of relapses occur without changes in driver mutations, suggesting that non-genetic mechanisms drive relapse in a large proportion of cases. We therefore characterized epigenetic patterns of AML relapse using 26 matched diagnosis-relapse samples with ATAC-seq. This analysis identified a relapse-specific chromatin accessibility signature for mutationally stable AML, suggesting that AML undergoes epigenetic evolution at relapse independent of mutational changes. Analysis of leukemia stem cell (LSC) chromatin changes at relapse indicated that this leukemic compartment underwent significantly less epigenetic evolution than non-LSCs, while epigenetic changes in non-LSCs reflected overall evolution of the bulk leukemia. Finally, we used single-cell ATAC-seq paired with mitochondrial sequencing (mtscATAC) to map clones from diagnosis into relapse along with their epigenetic features. We found that distinct mitochondrially-defined clones exhibit more similar chromatin accessibility at relapse relative to diagnosis, demonstrating convergent epigenetic evolution in relapsed AML. These results demonstrate that epigenetic evolution is a feature of relapsed AML and that convergent epigenetic evolution can occur following treatment with induction chemotherapy.
Project description:In acute myeloid leukemia (AML), leukemia stem cells (LSC) play a central role in disease progression and recurrence due to their intrinsic capacity for self-renewal and chemotherapy resistance. Whereas epigenetic mechanisms balance normal blood stem cell self-renewal and fate decisions, mutation and dysregulation of epigenetic regulators are considered fundamental to leukemia initiation and progression. Alterations in miRNA function represent a non-canonical epigenetic mechanism influencing malignant hematopoiesis, however the function of miRNA in human LSC remains undetermined. Here we show that miRNA profiling of fractionated AML populations defines an LSC-specific signature that is highly prognostic for patient survival. Gain- and loss-of-function analyses demonstrated that miR-126 restrained cell cycle progression, prevented differentiation, and increased self-renewal of human LSC. By targeting the G0 to G1 gatekeeper CDK3, miR-126 preserved LSC quiescence and promoted chemotherapy resistance. Thus, in AML, miRNAs influence patient outcome through post-transcriptional regulation of stemness programs in LSC.
Project description:Adipocyte conditioned media (ACM), stromal cell conditioned media (SCM) and unconditioned media (UCM) were added to B-cell Acute Lymphoblastic Leukemia cells (REH and RCH-AcV) either with or without methotrexate (MTX). The metabolomic profiles of the cells was determined by mass spectrometry.
Project description:Four acute lymphoblastic leukemia cell lines SUP-B15, JURKAT, MOLT-3, and CCRF-CEM cells were treated with glucocorticoids such as dexamethasone and prednisolone for six hours before RNA extraction.
Project description:The genetic lesions that drive acute megakaryoblastic leukemia (AMKL) have not been fully elucidated. To search for AMKL gene, we subjected 9 AMKL cell lines and 39 non-AMKL acute myeloid leukemia cell lines to microarray gene expression analysis.