Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

The ability of PML/RARα to initiate leukemia is associated with markedly increased proliferation of promyelocytes despite minor changes in the transcriptome and epigenome.

ABSTRACT: Acute Promyelocytic Leukemia is characterized by the accumulation in the blood and bone marrow of promyelocytes. The PML/RARα fusion protein is identified as the primary abnormality implicated in the pathology, and is believed to prevent transcription of genes necessary for normal myeloid development and differentiation. Identifying its targets is critical to comprehend the road to pathogenesis. To understand how PML/RARα, in the absence of secondary lesions, alters gene expression, DNA methylation and proliferation we used a novel experimental and sorting strategy to study normal versus preleukemic promyelocytes in vivo. Expression and methylation profiling analyses were performed on highly purified samples. Surprisingly, despite its ability to initiate leukemia, PML/RARα had overall minor effects on both the transcriptome and epigenome. Important regulators of the myeloid maturation program were not altered but, remarkably, PML/RARα promyelocytes showed strong downregulation of secondary and tertiary granule genes. Subtle changes were also observed on the DNA methylation profile, with PML/RARα predominantly mediating hypomethylation. We performed intersection studies between altered loci and previously described PML/RARα binding sites but found little overlap. Importantly, we show for the first time that PML/RARα on its own increases proliferation, and that this increased proliferation correlates with the ability to initiate leukemia. DNA methylation profiling in CD34(+) early promyelocytes and CD34(-) late promyelocytes cells from PML-RARa transgenic mice vs. control mice.

ORGANISM(S): Mus musculus

SUBMITTER: Maria Figueroa

PROVIDER: E-GEOD-54038 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Transcription and methylation analyses of preleukemic promyelocytes indicate a dual role for PML/RARA in leukemia initiation.

Gaillard Coline C Tokuyasu Taku A TA Rosen Galit G Sotzen Jason J Vitaliano-Prunier Adeline A Roy Ritu R Passegué Emmanuelle E de Thé Hugues H Figueroa Maria E ME Kogan Scott C SC

Haematologica 20150618 8

Acute promyelocytic leukemia is an aggressive malignancy characterized by the accumulation of promyelocytes in the bone marrow. PML/RARA is the primary abnormality implicated in this pathology, but the mechanisms by which this chimeric fusion protein initiates disease are incompletely understood. Identifying PML/RARA targets in vivo is critical for comprehending the road to pathogenesis. Utilizing a novel sorting strategy, we isolated highly purified promyelocyte populations from normal and youn ...[more]

PMID: 26088929

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Project description:The origin of aberrant DNA methylation in cancer remains largely unknown. In this study, we elucidated the DNA methylome in primary Acute Promyelocytic Leukemia (APL) and the role of PML-RARa in establishing these patterns. APL patients showed increased genome-wide DNA methylation with higher variability than healthy CD34+ cells, promyelocytes and remission bone marrow. A core set of differentially methylated regions in APL was identified. Age at diagnosis, Sanz score and Flt3-mutation status characterized methylation subtypes. Transcription factor binding sites, e.g. c-myc binding sites were associated with low methylation. SUZ12 and REST binding sites identified in embryonic stem cells were, however, preferentially DNA hypermethylated in APL. Unexpectedly, PML-RARa binding sites were also protected from aberrant DNA methylation in APL. In line, myeloid cells from pre-leukemic PML-RARa knock-in mice did not show altered DNA methylation and expression of PML-RARa in hematopoietic progenitor cells prevented differentiation without affecting DNA methylation. ATRA treatment of APL blasts did also not result in DNA methylation changes. These results suggest that aberrant DNA methylation is associated with leukemia phenotype but not required for PML-RARa-mediated initiation of leukemogenesis. We used Reduced Representation Bisulfite Sequencing (RRBS) to determine the genome-wide methylation signature of 18 primary APL patient samples. We then compared the APL methylation signature with methylation patterns found in CD34+ progenitor cells (n=4), promyelocytes (n=4) and remission bone marrow samples (n=8). Differentially methylated regions found in all three comparisons (APL vs. all three control specimens) were then further analyzed for genomic localization, variability and association with clinical parameters. Finally, the relationship between differentially methylated regions in APL and specific transcription factor binding sites was analyzed. For this purpose, ChiP-Sequencing of SUZ12 and REST was performed in primary APL patient blasts. To further determine the contribution of the leukemogenic transcription factor PML-RARa to methylation in APL, we also performed RRBS in pre-leukemic PML-RARa knock-in mice and hematopoetic progenitor cells retrovirally transduced with PML-RARa.

Dataset Information

The ability of PML/RARα to initiate leukemia is associated with markedly increased proliferation of promyelocytes despite minor changes in the transcriptome and epigenome.

Publications

Transcription and methylation analyses of preleukemic promyelocytes indicate a dual role for PML/RARA in leukemia initiation.

Similar Datasets

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