Genome-Wide Regulation of Cpg Methylation by Eccebpα in Acute Myeloid Leukemia [Version 1; Peer Review: 1 Approved, 1 Approved with Reservations]
Total Page:16
File Type:pdf, Size:1020Kb
F1000Research 2021, 10:204 Last updated: 31 AUG 2021 RESEARCH ARTICLE Genome-wide regulation of CpG methylation by ecCEBPα in acute myeloid leukemia [version 1; peer review: 1 approved, 1 approved with reservations] Adewale J. Ogunleye 1, Ekaterina Romanova2, Yulia A. Medvedeva1,2 1Department of Biological and Medical Physics, Moscow Institute of Physics and Technology, Moscow, Russian Federation 2Research Center of Biotechnology, Institute of Bioengineering, Russian Academy of Sciences, Moscow, Russian Federation v1 First published: 11 Mar 2021, 10:204 Open Peer Review https://doi.org/10.12688/f1000research.28146.1 Latest published: 31 Aug 2021, 10:204 https://doi.org/10.12688/f1000research.28146.2 Reviewer Status Invited Reviewers Abstract Background: Acute myeloid leukemia (AML) is a hematopoietic 1 2 malignancy characterized by genetic and epigenetic aberrations that alter the differentiation capacity of myeloid progenitor cells. The version 2 transcription factor CEBPα is frequently mutated in AML patients (revision) leading to an increase in DNA methylation in many genomic locations. 31 Aug 2021 Previously, it has been shown that ecCEBPα (extra coding CEBPα) - a lncRNA transcribed in the same direction as CEBPα gene - regulates version 1 DNA methylation of CEBPα promoter in cis. Here, we hypothesize that 11 Mar 2021 report report ecCEBPα could participate in the regulation of DNA methylation in trans. 1. Amrita Singh , CSIR Institute of Genomics Method: First, we retrieved the methylation profile of AML patients with mutated CEBPα locus from The Cancer Genome Atlas (TCGA). We and Integrative Biology (CSIR-IGIB), New then predicted the ecCEBPα secondary structure in order to check the Delhi, India potential of ecCEBPα to form triplexes around CpG loci and checked if triplex formation influenced CpG methylation, genome-wide. 2. Oleg N. Demidov , University of Results: Using DNA methylation profiles of AML patients with a Bourgogne-Franche Comté, Dijon, France mutated CEBPα locus, we show that ecCEBPα could interact with DNA by forming DNA:RNA triple helices and protect regions near its Any reports and responses or comments on the binding sites from global DNA methylation. Further analysis revealed article can be found at the end of the article. that triplex-forming oligonucleotides in ecCEBPα are structurally unpaired supporting the DNA-binding potential of these regions. ecCEBPα triplexes supported with the RNA-chromatin co-localization data are located in the promoters of leukemia-linked transcriptional factors such as MLF2. Discussion: Overall, these results suggest a novel regulatory mechanism for ecCEBPα as a genome-wide epigenetic modulator through triple-helix formation which may provide a foundation for sequence-specific engineering of RNA for regulating methylation of specific genes. Page 1 of 15 F1000Research 2021, 10:204 Last updated: 31 AUG 2021 Keywords Acute myeloid leukemia, Triplex, DNA methylation, long non coding RNA, extra-coding CEBPα Corresponding author: Adewale J. Ogunleye ([email protected]) Author roles: Ogunleye AJ: Formal Analysis, Investigation, Methodology, Validation, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing; Romanova E: Conceptualization, Data Curation, Supervision; Medvedeva YA: Conceptualization, Funding Acquisition, Methodology, Resources, Software, Supervision, Validation, Visualization, Writing – Review & Editing Competing interests: No competing interests were disclosed. Grant information: The work has been partially supported by Russian Science Foundation (grant 18-14-00240) to YAM and the Ministry of the Sciences and Higher Education of the Russian Federation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Copyright: © 2021 Ogunleye AJ et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. How to cite this article: Ogunleye AJ, Romanova E and Medvedeva YA. Genome-wide regulation of CpG methylation by ecCEBPα in acute myeloid leukemia [version 1; peer review: 1 approved, 1 approved with reservations] F1000Research 2021, 10:204 https://doi.org/10.12688/f1000research.28146.1 First published: 11 Mar 2021, 10:204 https://doi.org/10.12688/f1000research.28146.1 Page 2 of 15 F1000Research 2021, 10:204 Last updated: 31 AUG 2021 Introduction granulocyte differentiation20. Mechanistic studies via reduced Acute myeloid leukemia (AML) is a malignant tumor charac- representation bisulfite sequencing and RNA immunoprecipita- terized by the proliferation of undifferentiated myeloblasts1,2. tion sequencing shows that ecCEBPα suppresses DNA meth- It is the most prevalent form of leukemia in older adults ylation in cis- by acting as a shield that sequesters DNMT1 (>60 years) with an annual mortality rate of 50% and a 5-year from the CEBPα promoter. We speculate that ecCEBPα could survival rate of 24%2,3. With the combined effects of the global regulate DNMT1 activities in distant DNA regions (in trans-) increase in average life expectancy and AML drug inefficiency, as well. The mechanism of this potential interaction is to be the number of patients is expected to significantly increase determined. in the coming years4,5. Methods The current understanding of the molecular interplay in AML ecCEBPα sequence has been defined under two distinct categories; (i) genetic In the recent version of GENCODE, ecCEBPα is not anno- abnormalities and (ii) non-random chromosomal rearrangements. tated most likely due to an overlap with a protein-coding gene Cases of AML with chromosomal rearrangements as t(15;17) CEBPα on the same strand. We retrieved the complete ecCEBPα [PML-RARA], t(9;22) [BCR-ABL], inv(16) [CBFB-MYH11], sequence from the human genome (hg19, chr19: 33298573- t(8;21) [RUNX1-ETO] are called cytogenetically abnormal 33303358) based on information reported in the work of (CA-AML), while cases with genetic abnormalities (including Di Ruscio et al.20. ecCEBPα is approximately 4.8kb and it over- frequent mutations in DNMT3A, NPM1, CEBPα, IDH1/2, TET2, laps with the intronless CEBPα gene (~2.6kb) on the same FLT3-ITD) are called cytogenetically normal (CN-AML)1,4. strand. ecCEBPα does not share either the same transcription The former accounts for 50–55%, while the latter accounts for start site (TSS) or transcription end site (TES) with CEBPα, start- 45–50% of diagnosed AML cases6,7. Even though these muta- ing ~0.89kb upstream and ending ~1.46kb downstream of the tions and chromosomal alterations are crucial for initiating CEBPα gene. AML, they are not sufficient to explain AML progression, 8 heterogeneity, and relapse . DNA methylation data processing CpG methylation (Illumina 450K array) and CEBPα muta- Recently, studies have identified the role of non-coding tion data for 186 AML patients were retrieved from the Cancer RNAs, especially long non-coding RNAs (lncRNA) in the ini- Genome Atlas (TCGA: http://firebrowse.org). CpG methyla- tiation and progression of cancers9–11. LncRNAs are emerging tion levels were measured in 307796 unique loci. We split all the functional transcriptional products of at least 200 nucleotides AML patients into two groups based on CEBPα mutation status lacking an open reading frame. Although they account for a (13 patients with a CEBPα mutation and 173 patients without a large proportion of transcriptional products in mammals (about mutation). We classified a CpG position as hypermethylated 58,000 loci)12, only a small number of lncRNAs have been (HM) in patients with a CEBPα locus mutation if DNA meth- well characterized. Although lncRNAs are mostly not con- ylation level was significantly increased in the case of a served evolutionarily, they are heavily regulated suggesting their CEBPα mutation (t-test, FDR ≤0.05 and Δ-value ≥0.1) and all functional role12,13. They may function either as signal trans- non-hypermethylated (NHM) CpG in the case of a CEBPα ducers, protein guides, or molecular scaffolds to regulate mutation were classified as non-hypermethylated CpGs (t-test, transcriptional and epigenetic events14–16. Some lncRNAs per- FDR >0.05 and |Δ-value| <0.1). As a result, we obtained 11955 form these functions in cis- by modulating transcription of HM and 261433 NHM CpGs. nearby genes (Dum)17 or act in trans-, by modulating genes 18 at multiple distant loci (MALAT1) , while some can do both Secondary structure and triplex prediction (HOTAIR)9,19. As suggested in a previous study22, unpaired RNA nucleotides are more likely to form triplexes with DNA. We predicted Recent studies have identified lncRNAs for their remark- RNA secondary structure using RNAplfold (V 2.4.14), from able role in regulating major epigenetic processes such as DNA the Vienna suite using a cut-off for pairing probability (-c) of methylation and chromatin remodeling. DNA methylation in 0.123,24. To search for potential interactions between ecCEBPα mammals is coordinated by one of the three DNA methyl- and DNA target regions we used only unpaired nucleotides, transferases (DNMT); DNMT1, DNMT3A, and DNMT3B7,17,20. while the nucleotides predicted to pair were replaced with ‘N’. LncRNAs have been identified in recent studies as important agents that can modulate DNA methylation, either by activating or DNA target regions were defined as 100 nucleotides centered at repressing DNMTs. For example, the