Project description:DNA methyltransferase 3A (DNMT3A) gene is mutated in various myeloid neoplasms including acute myeloid leukemia (AML), especially at the Arg882 and associated with inferior outcomes. Despite the current progress of functional role of DNMT3A mutations, the molecular pathogenesis of myeloid malignancies remains poorly understood. The mechanisms of AML transformation and functional role of DNMT3A mutations through its target genes in the leukemogenesis remain to be explored. Here we wished to perform the differential genomic-methylation profile in U937 cells over-expressed with DNMT3A-Arg882His/Cys (R882H/C) mutations including DNMT3A-WT and vector using Illumina MethylationEPIC BeadChip microarray. Results: Differential genomic-methylation assess identified both hypo- and hypermethylation features in different regions throughout the whole genome of DNMT3A mutants-transduced U937 cells.
Project description:DNA methyltransferase 3A (DNMT3A) gene is mutated in various myeloid neoplasms including acute myeloid leukemia (AML), especially at the Arg882 and associated with inferior outcomes. Despite the current progress of functional role of DNMT3A mutations, the molecular pathogenesis of myeloid malignancies remains poorly understood. The mechanisms of AML transformation and functional role of DNMT3A mutations through its target genes in the leukemogenesis remain to be explored. Here we wished to perform the differential gene expression profile in U937 cells over-expressed with DNMT3A-Arg882His/Cys (R882H/C) mutations including DNMT3A-WT and vector. Results: Gene expression profiling analysis revealed aberrant expression of several cell-cycle and apoptosis-related genes in U937 cells transduced with mutant DNMT3A compared to WT- or vector control.
Project description:DNA methyltransferase 3A (DNMT3A) gene is mutated in various myeloid neoplasms including acute myeloid leukemia (AML), especially at the Arg882 and associated with inferior outcomes. Here we wished to perform the differential genomic-methylation profile in EOL-1 cells over-expressed with DNMT3A-Arg882Cys(R882C) and DNMT3A-Ser714Cys (S714C) mutations including DNMT3A-WT and vector. Results: Differential genomic-methylation assess identified both hypo- and hypermethylation features in different regions throughout the whole genome of DNMT3A mutants-transduced EOL-1 cells.
Project description:Despite the impact of DNMT3A mutation in acute myeloid leukemia has been emphasized, the precise molecular mechanisms in leukemogenesis are largely unknown. Here we show that, in murine transplantation experiments, recipients transplanted with DNMT3A mutant-transduced cells exhibit aberrant hematopoietic stem cell (HSC) accumulation. Differentiation-associated genes are down-regulated without accompanying changes in methylation status of their promoter-associated CpG islands in DNMT3A mutant-transduced stem/progenitor cells. DNMT3A mutant also promotes monoblastic transformation in vitro in combination with HOXA9. Molecularly, DNMT3A mutant interacts with polycomb repressive complex 1 (PRC1), leading to transcriptional silencing of PU.1. Suppression of PRC1 impairs aberrant HSC accumulation and monoblastic transformation. Taken together, our results highlight the functional role of DNMT3A mutation, forming the basis for leukemia development. GFP-labeled empty vector, DNMT3A wild-type (WT), R882H-transduced LSK cells derived from transplanted mice were utilized for compared the expression profiles (3 sorted empty vector-transduced LSK cells, 3 sorted DNMT3A WT-transduced LSK cells, and 3 sorted DNMT3A R882H-transduced LSK cells. Total RNA was extracted by TaKaRa NucleoSpin RNA XS according to the manufacturerâs protocol. Amplification and biotin labeling of fragmented cDNA was carried out from 3.67 ng of total RNA by using NuGen Ovation Pico WTA System V2 (NuGEN) and SureTag Complete DNA Labeling Kit (Agilent). Each 2 μg of cDNA were hybridized to the Agilent SurePrint G3 Mouse Gene Expression 8x60K (Agilent) using Gene Expression Hybridization Kit (Agilent). After scanning, the signal intensity for each feature was measured by Agilent Feature Extraction (Agilent).
Project description:Despite the impact of DNMT3A mutation in acute myeloid leukemia has been emphasized, the precise molecular mechanisms in leukemogenesis are largely unknown. Here we show that, in murine transplantation experiments, recipients transplanted with DNMT3A mutant-transduced cells exhibit aberrant hematopoietic stem cell (HSC) accumulation. Differentiation-associated genes are down-regulated without accompanying changes in methylation status of their promoter-associated CpG islands in DNMT3A mutant-transduced stem/progenitor cells. DNMT3A mutant also promotes monoblastic transformation in vitro in combination with HOXA9. Molecularly, DNMT3A mutant interacts with polycomb repressive complex 1 (PRC1), leading to transcriptional silencing of PU.1. Suppression of PRC1 impairs aberrant HSC accumulation and monoblastic transformation. Taken together, our results highlight the functional role of DNMT3A mutation, forming the basis for leukemia development.
Project description:Somatic DNMT3A R882 codon mutations drive the most common form of clonal haematopoiesis (CH) and are associated with increased acute myeloid leukaemia (AML) risk1,2. Preventing expansion of DNMT3A-R882-mutant haematopoietic stem/progenitor cells (HSPCs) may therefore avert progression to AML. To identify DNMT3A-R882-mutant-specific vulnerabilities, we conducted a genome-wide CRISPR screen on primary mouse Dnmt3aR882H/+ HSPCs. Amongst the 640 vulnerability genes identified, many were involved in mitochondrial metabolism and metabolic flux analysis confirmed enhanced oxidative phosphorylation usage in Dnmt3aR882H/+ vs Dnmt3a+/+ (WT) HSPCs. We selected citrate/malate transporter Slc25a1 and complex I component Ndufb11, for which pharmacological inhibitors are available, for downstream studies. In vivo administration of SLC25A1 inhibitor CTPI2 and complex I inhibitors IACS-010759 and metformin, suppressed post-transplantation clonal expansion of Dnmt3aR882H/+, but not WT, LT-HSCs. The effect of metformin was recapitulated using a primary human DNMT3A-R882 CH sample. Notably, analysis of 412,234 UK Biobank participants revealed that individuals taking metformin had markedly lower prevalence of DNMT3A-R882-mutant CH, after controlling for potential confounders including glycated haemoglobin, diabetes and body mass index. Collectively, our data propose that modulation of mitochondrial metabolism as a therapeutic strategy for prevention of DNMT3A-R882-mutant AML.
Project description:Purpose: DNA methyltransferase 3A (DNMT3A) mediates de novo DNA methylation. Mutations in DNMT3A are associated with hematological malignancies, most frequently acute myeloid leukemia. DNMT3A mutations are hypothesized to establish a pre-leukemic state, rendering cells vulnerable to secondary oncogenic mutations and malignant transformation. However, the mechanisms by which DNMT3A mutations contribute to leukemogenesis are not well-defined. Methods: Methylated DNA immunoprecipitation (MeDIP) was used to detect regional differences in DNA methylation between DNMT3A WT and MT clones. DNA extraction of WTblk, WT1, MT1, MT2, and MT4 cell lines was performed as previously described. 5-mC profiling, fragmentation, library preparation and sequencing were performed by Otogenetics (Atlanta, GA, USA). In brief, paired-end libraries were generated using the Illumina TruSeq DNA sample preparation kit. Illumina HiSeq2500 was used for sequencing with a paired-end sequencing length of 100-125 bp and approximately 40 million reads per sample. Results: We attempted to identify differentially methylated genes based on DNMT3A mutation status and found very few regions of differential methylation between WT and MT cell lines (Figure 3C), which did not exceed the number of regions expected to exhibit differential methylation by chance alone. These data suggest that regional methylation patterns do not differ between DNMT3A MT and WT cell lines in our gene-edited K562 cells. Conclusions: CRISPR/Cas9-mediated DNMT3A-mutated K562 cells may be used to model effects of DNMT3A mutations in human cells. Our findings implicate aberrant splicing and induction of genomic instability as potential mechanisms by which DNMT3A mutations might predispose to malignancy.