scholarly journals Genome-wide methylation sequencing identifies progression-related epigenetic drivers in myelodysplastic syndromes

2020 ◽  
Vol 11 (11) ◽  
Author(s):  
Jing-dong Zhou ◽  
Ting-juan Zhang ◽  
Zi-jun Xu ◽  
Zhao-qun Deng ◽  
Yu Gu ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Myelodysplastic Syndromes ◽  
Bisulfite Sequencing ◽  
De Novo ◽  
Dna Hypermethylation ◽  
Reduced Representation ◽  
Targeted Bisulfite Sequencing ◽  
Specific Pcr ◽  
Genome Wide ◽  
Potential Biomarker

AbstractThe potential mechanism of myelodysplastic syndromes (MDS) progressing to acute myeloid leukemia (AML) remains poorly elucidated. It has been proved that epigenetic alterations play crucial roles in the pathogenesis of cancer progression including MDS. However, fewer studies explored the whole-genome methylation alterations during MDS progression. Reduced representation bisulfite sequencing was conducted in four paired MDS/secondary AML (MDS/sAML) patients and intended to explore the underlying methylation-associated epigenetic drivers in MDS progression. In four paired MDS/sAML patients, cases at sAML stage exhibited significantly increased methylation level as compared with the matched MDS stage. A total of 1090 differentially methylated fragments (DMFs) (441 hypermethylated and 649 hypomethylated) were identified involving in MDS pathogenesis, whereas 103 DMFs (96 hypermethylated and 7 hypomethylated) were involved in MDS progression. Targeted bisulfite sequencing further identified that aberrant GFRA1, IRX1, NPY, and ZNF300 methylation were frequent events in an additional group of de novo MDS and AML patients, of which only ZNF300 methylation was associated with ZNF300 expression. Subsequently, ZNF300 hypermethylation in larger cohorts of de novo MDS and AML patients was confirmed by real-time quantitative methylation-specific PCR. It was illustrated that ZNF300 methylation could act as a potential biomarker for the diagnosis and prognosis in MDS and AML patients. Functional experiments demonstrated the anti-proliferative and pro-apoptotic role of ZNF300 overexpression in MDS-derived AML cell-line SKM-1. Collectively, genome-wide DNA hypermethylation were frequent events during MDS progression. Among these changes, ZNF300 methylation, a regulator of ZNF300 expression, acted as an epigenetic driver in MDS progression. These findings provided a theoretical basis for the usage of demethylation drugs in MDS patients against disease progression.

scholarly journals Genome-Wide Methylation Sequencing Identifies Progression-Related Epigenetic Drivers in Myelodysplastic Syndromes

2020 ◽  
Author(s):  
Jing-dong Zhou ◽  
Ting-juan Zhang ◽  
Zi-jun Xu ◽  
Zhao-qun Deng ◽  
Yu Gu ◽  
...  
Keyword(s):  
Disease Progression ◽  
Cancer Progression ◽  
Myelodysplastic Syndromes ◽  
Bisulfite Sequencing ◽  
De Novo ◽  
Dna Hypermethylation ◽  
Genome Wide ◽  
Potential Biomarker ◽  
Frequent Event

Abstract Background: The mechanism underlying disease progression of myelodysplastic syndromes (MDS) to acute myeloid leukemia (AML) remains poorly elucidated. Epigenetic alterations are increasingly implicated in the pathogenesis of cancer progression including MDS. However, little studies explored the whole-genome methylation alterations during MDS progression.Methods: We conducted reduced representation bisulfite sequencing in four paired MDS/secondary AML (MDS/sAML) patients and intended to discover methylation-associated epigenetic drivers in MDS progression.Results: In four paired MDS/sAML patients, cases at sAML stage showed significantly increased methylation level when compared with their matched MDS stage. A total of 1090 differentially methylated fragments (DMFs) (441 hypermethylated and 649 hypomethylated) were identified involved in MDS pathogenesis, whereas 103 DMFs (96 hypermethylated and 7 hypomethylated) were identified involved in MDS progression. Further targeted bisulfite sequencing identified aberrant GFRA1, IRX1, NPY, and ZNF300 methylation was frequent events in additional de novo MDS and AML patients, of which only ZNF300 methylation was associated with ZNF300 expression. Moreover, ZNF300 hypermethylation in larger cohorts of de novo MDS and AML patients was further confirmed by real-time quantitative methylation-specific PCR. Clinical studies showed that ZNF300 methylation could act as a potential biomarker helpful for the diagnosis and prognosis in MDS and AML patients. In in vitro experiments, overexpression of ZNF300 exhibited anti-proliferative and pro-apoptotic effects in MDS-derived AML cell line SKM-1.Conclusions: Genome-wide DNA hypermethylation was a frequent event during MDS progression. Among these changes, ZNF300 methylation through the regulation of ZNF300 expression acted as an epigenetic driver in MDS progression. These findings give a theoretical basis for investigating and using the efficacy of DNMT inhibitors in MDS patients against disease progression, and provide new insights for targeted therapy in MDS.

scholarly journals Parallel adaptations to an altitudinal gradient persist in tetraploid snowtrout (Cyprinidae: Schizothorax), despite extensive genomic exchange within adjacent Himalayan rivers

2021 ◽  
Author(s):  
Tyler K Chafin ◽  
Binod Regmi ◽  
Marlis R. Douglas ◽  
David R. Edds ◽  
Karma Wangchuk ◽  
...  
Keyword(s):  
De Novo ◽  
Genomic Islands ◽  
Secondary Contact ◽  
Evolutionary Patterns ◽  
Ploidy Levels ◽  
Reduced Representation ◽  
Genome Wide ◽  
Genealogical Concordance ◽  
Genomic Approach ◽  
The Ganges

Replicated evolutionary patterns are often attributed to recurrent emergence following parallel selective pressures. However, similar genetic patterns (e.g., 'genomic islands') can also emerge following extensive homogenization in secondary contact, as a by-product of heterogeneous introgression. For example, within Himalayan tributaries of the Ganges/Brahmaputra rivers, drainage-specific mtDNA clades of polyploid snowtrout (Cyprinidae: Schizothorax) are partitioned as co-occurring morphological 'ecotypes,' hypothesized to represent parallel divergence among adjacent streams. To evaluate this scenario, we utilized a reduced-representation genomic approach (N=35,319 de-novo and N=10,884 transcriptome-aligned SNPs) applied to high-altitude Nepali/Bhutanese snowtrout (N=48 each). We unambiguously quantified ploidy levels by first deriving genome-wide allelic depths followed by ploidy-aware Bayesian models that produced genotypes statistically consistent with diploid/tetraploid expectations. When genotyped SNPs were clustering within drainages, the convergence of eco-phenotypes was sustained. However, subsequent partitioned analyses of phylogeny and population admixture instead identified subsets of loci under selection which retained genealogical concordance with morphology, with apparent patterns of parallel ecotype emergence instead driven by widespread genomic homogenization. Here, prior isolation is effectively masked by admixture occurring in secondary contact. We note two salient factors:1) Polyploidy has promoted homogenization in tetraploid Himalayan snowtrout; and 2) Homogenization varies across Himalayan tributaries, presumably in lockstep with extent of anthropogenic modification.

scholarly journals Epigenetic Deregulation of Protocadherin PCDHGC3 in Pheochromocytomas/Paragangliomas Associated With SDHB Mutations

2019 ◽  
Vol 104 (11) ◽  
pp. 5673-5692 ◽  
Author(s):  
Cristóbal Bernardo-Castiñeira ◽  
Nuria Valdés ◽  
Lucía Celada ◽  
Andrés San José Martinez ◽  
I Sáenz-de-Santa-María ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Promoter Methylation ◽  
De Novo ◽  
Gene Promoter ◽  
Gene Clusters ◽  
Suppressor Gene ◽  
Migration And Invasion ◽  
Primary Tumors ◽  
Genome Wide ◽  
Potential Biomarker

Abstract Context SDHB mutations are found in an increasing number of neoplasms, most notably in paragangliomas and pheochromocytomas (PPGLs). SDHB-PPGLs are slow-growing tumors, but ∼50% of them may develop metastasis. The molecular basis of metastasis in these tumors is a long-standing and unresolved problem. Thus, a better understanding of the biology of metastasis is needed. Objective This study aimed to identify gene methylation changes relevant for metastatic SDHB-PPGLs. Design We performed genome-wide profiling of DNA methylation in diverse clinical and genetic PPGL subtypes, and validated protocadherin γ-C3 (PCDHGC3) gene promoter methylation in metastatic SDHB-PPGLs. Results We define an epigenetic landscape specific for metastatic SDHB-PPGLs. DNA methylation levels were found significantly higher in metastatic SDHB-PPGLs than in SDHB-PPGLs without metastases. One such change included long-range de novo methylation of the PCDHA, PCDHB, and PCDHG gene clusters. High levels of PCDHGC3 promoter methylation were validated in primary metastatic SDHB-PPGLs, it was found amplified in the corresponding metastases, and it was significantly correlated with PCDHGC3 reduced expression. Interestingly, this epigenetic alteration could be detected in primary tumors that developed metastasis several years later. We also show that PCDHGC3 down regulation engages metastasis-initiating capabilities by promoting cell proliferation, migration, and invasion. Conclusions Our data provide a map of the DNA methylome episignature specific to an SDHB-mutated cancer and establish PCDHGC3 as a putative suppressor gene and a potential biomarker to identify patients with SDHB-mutated cancer at high risk of metastasis who might benefit from future targeted therapies.

Rapid and affordable genome-wide bisulfite DNA sequencing by XmaI-reduced representation bisulfite sequencing

Epigenomics ◽  
2017 ◽  
Vol 9 (6) ◽  
pp. 833-847 ◽  
Author(s):  
Alexander S Tanas ◽  
Marina E Borisova ◽  
Ekaterina B Kuznetsova ◽  
Viktoria V Rudenko ◽  
Kristina O Karandasheva ◽  
...  
Keyword(s):  
Dna Sequencing ◽  
Bisulfite Sequencing ◽  
Reduced Representation ◽  
Genome Wide ◽  
Reduced Representation Bisulfite Sequencing

scholarly journals Evaluating the Consistency of Gene Methylation in Liver Cancer Using Bisulfite Sequencing Data

2021 ◽  
Vol 9 ◽  
Author(s):  
Xubin Zheng ◽  
Qiong Wu ◽  
Haonan Wu ◽  
Kwong-Sak Leung ◽  
Man-Hon Wong ◽  
...  
Keyword(s):  
Liver Cancer ◽  
Dna Sequences ◽  
Bisulfite Sequencing ◽  
Differentially Methylated Region ◽  
Sequencing Data ◽  
Reduced Representation ◽  
Targeted Bisulfite Sequencing ◽  
Differentially Methylated Genes ◽  
Genome Bisulfite Sequencing ◽  
Bisulfite Sequencing Data

Bisulfite sequencing is considered as the gold standard approach for measuring DNA methylation, which acts as a pivotal part in regulating a variety of biological processes without changes in DNA sequences. In this study, we introduced the most prevalent methods for processing bisulfite sequencing data and evaluated the consistency of the data acquired from different measurements in liver cancer. Firstly, we introduced three commonly used bisulfite sequencing assays, i.e., reduced-representation bisulfite sequencing (RRBS), whole-genome bisulfite sequencing (WGBS), and targeted bisulfite sequencing (targeted BS). Next, we discussed the principles and compared different methods for alignment, quality assessment, methylation level scoring, and differentially methylated region identification. After that, we screened differential methylated genes in liver cancer through the three bisulfite sequencing assays and evaluated the consistency of their results. Ultimately, we compared bisulfite sequencing to 450 k beadchip and assessed the statistical similarity and functional association of differentially methylated genes (DMGs) among the four assays. Our results demonstrated that the DMGs measured by WGBS, RRBS, targeted BS and 450 k beadchip are consistently hypo-methylated in liver cancer with high functional similarity.

scholarly journals Genome wide efficiency profiling reveals modulation of maintenance and de novo methylation by Tets

2020 ◽  
Author(s):  
Pascal Giehr ◽  
Charalampos Kyriakopoulos ◽  
Karl Nordström ◽  
Abduhlrahman Salhab ◽  
Fabian Müller ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Epigenetic Modification ◽  
Embryonic Stem ◽  
Regulatory Elements ◽  
Sequencing Data ◽  
Reduced Representation ◽  
Genome Wide ◽  
Global And Local

AbstractBackgroundDNA methylation is an essential epigenetic modification which is set and maintained by DNA methyl transferases (Dnmts) and removed via active and passive mechanisms involving Tet mediated oxidation. While the molecular mechanisms of these enzymes are well studied, their interplay on shaping cell specific methylomes remains less well understood. In our work we model the activities of Tets and Dnmts at single CpGs across the genome using a novel type of high resolution sequencing data.ResultsTo accurately measure 5mC and 5hmC levels at single CpGs we developed RRHPoxBS, a reduced representation hairpin oxidative bisulfite sequencing approach. Using this method we mapped the methylomes and hydroxymethylomes of wild type and Tet triple knockout mouse embryonic stem cells. These comprehensive datasets were then used to develop an extended Hidden Markov model allowing us i) to determine the symmetrical methylation and hydroxymethylation state at millions of individual CpGs, ii) infer the maintenance and de novo methylation efficiencies of Dnmts and the hydroxylation efficiencies of Tets at individual CpG positions. We find that Tets exhibit their highest activity around unmethylated regulatory elements, i.e. active promoters and enhancers. Furthermore, we find that Tets’ presence has a profound effect on the global and local maintenance and de novo methylation activities by the Dnmts, not only substantially contributing to a universal demethylation of the genome but also shaping the overall methylation landscape.ConclusionsOur analysis demonstrates that a fine tuned and locally controlled interplay between Tets and Dnmts is important to modulate de novo and maintenance activities of Dnmts across the genome. Tet activities contribute to DNA methylation patterning in the following ways: They oxidize 5mC, they locally shield DNA from accidental de novo methylation and at the same time modulate maintenance and de novo methylation efficiencies of Dnmts across the genome.

scholarly journals Methylation Markers in Cutaneous Melanoma: Unravelling the Potential Utility of Their Tracking by Liquid Biopsy

Cancers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 6217
Author(s):  
Valentina Aleotti ◽  
Cristina Catoni ◽  
Cristina Poggiana ◽  
Antonio Rosato ◽  
Antonella Facchinetti ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Cancer Progression ◽  
Liquid Biopsy ◽  
Circulating Tumor Dna ◽  
Response To Therapy ◽  
Recent Advances ◽  
Genome Wide ◽  
Potential Biomarker ◽  
Life Threatening ◽  
And Migration

Malignant melanoma is the most serious, life-threatening form of all dermatologic diseases, with a poor prognosis in the presence of metastases and advanced disease. Despite recent advances in targeted therapy and immunotherapy, there is still a critical need for a better understanding of the fundamental mechanisms behind melanoma progression and resistance onset. Recent advances in genome-wide methylation methods have revealed that aberrant changes in the pattern of DNA methylation play an important role in many aspects of cancer progression, including cell proliferation and migration, evasion of cell death, invasion, and metastasization. The purpose of the current review was to gather evidence regarding the usefulness of DNA methylation tracking in liquid biopsy as a potential biomarker in melanoma. We investigated the key genes and signal transduction pathways that have been found to be altered epigenetically in melanoma. We then highlighted the circulating tumor components present in blood, including circulating melanoma cells (CMC), circulating tumor DNA (ctDNA), and tumor-derived extracellular vesicles (EVs), as a valuable source for identifying relevant aberrations in DNA methylation. Finally, we focused on DNA methylation signatures as a marker for tracking response to therapy and resistance, thus facilitating personalized medicine and decision-making in the treatment of melanoma patients.

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