Project description:DNA methylation changes in neuroblastoma, a clinically-heterogeneous pediatric tumor, have been described essentially in promoter regions. We analyzed the DNA methylome of neuroblastoma using high-density microarrays and observed differential methylation not only in promoters but also in intragenic and intergenic regions at both CpG and non-CpG sites. These epigenetic changes showed a non-random distribution relative functional chromatin domains, and targeted development and cancer-related genes, relevant for neuroblastoma pathogenesis. CCND1, a gene overexpressed in neuroblastoma, showed hypomethylation of gene-body and upstream regulatory regions. Furthermore, tumors with diverse clinical-risk showed clear differences affecting CpG and, remarkably, non-CpG sites. Non-CpG methylation was present in clinically-favorable tumors and affected genes such as ALK, where non-CpG methylation correlated with low gene expression. Finally, we identified CpG and non-CpG methylation signatures which correlated with patient’s age at time-points relevant for neuroblastoma clinical behavior, and targeted genes related to neural development and neural crest regulatory network We report on the first DNA methylomes of neuroblastoma tumors using high-density microarrays. DNA methylation changes in this pediatric tumor affected both CpG and non-CpG sites associated with developmental and cancer-related genes such as CCND1 and ALK. Our study also provides new insights into the molecular basis of the heterogeneous clinical behavior of neuroblastoma.
Project description:DNA methylation changes in neuroblastoma, a clinically-heterogeneous pediatric tumor, have been described essentially in promoter regions. We analyzed the DNA methylome of neuroblastoma using high-density microarrays and observed differential methylation not only in promoters but also in intragenic and intergenic regions at both CpG and non-CpG sites. These epigenetic changes showed a non-random distribution relative functional chromatin domains, and targeted development and cancer-related genes, relevant for neuroblastoma pathogenesis. CCND1, a gene overexpressed in neuroblastoma, showed hypomethylation of gene-body and upstream regulatory regions. Furthermore, tumors with diverse clinical-risk showed clear differences affecting CpG and, remarkably, non-CpG sites. Non-CpG methylation was present in clinically-favorable tumors and affected genes such as ALK, where non-CpG methylation correlated with low gene expression. Finally, we identified CpG and non-CpG methylation signatures which correlated with patient’s age at time-points relevant for neuroblastoma clinical behavior, and targeted genes related to neural development and neural crest regulatory network We report on the first DNA methylomes of neuroblastoma tumors using high-density microarrays. DNA methylation changes in this pediatric tumor affected both CpG and non-CpG sites associated with developmental and cancer-related genes such as CCND1 and ALK. Our study also provides new insights into the molecular basis of the heterogeneous clinical behavior of neuroblastoma.
Project description:DNA methylation changes at CpG and non-CpG sites are associated with development and clinical behavior in neuroblastoma [gene expression]
Project description:Aim: Innate circadian rhythms are critical for optimal tissue-specific functions, including skeletal muscle, a major insulin-sensitive tissue responsible for glucose homeostasis. We determined whether transcriptional oscillations are associated with CpG methylation changes in skeletal muscle. Materials & methods: We performed rhythmicity analysis on the transcriptome and CpG methylome of circadian synchronized myotubes. Results: We identified several transcripts and CpG-sites displaying oscillatory behavior, which were enriched with GO terms related to metabolism and development. Oscillating CpG methylation was associated with rhythmic expression of 31 transcripts. Conclusion: Although circadian oscillations may be regulated by rhythmic DNA methylation, strong rhythmic associations between transcriptome and CpG methylation were not identified. This resource constitutes a transcriptomic/epigenomic atlas of skeletal muscle and regulation of circadian rhythms.
Project description:Aim: Innate circadian rhythms are critical for optimal tissue-specific functions, including skeletal muscle, a major insulin-sensitive tissue responsible for glucose homeostasis. We determined whether transcriptional oscillations are associated with CpG methylation changes in skeletal muscle. Materials & methods: We performed rhythmicity analysis on the transcriptome and CpG methylome of circadian synchronized myotubes. Results: We identified several transcripts and CpG-sites displaying oscillatory behavior, which were enriched with GO terms related to metabolism and development. Oscillating CpG methylation was associated with rhythmic expression of 31 transcripts. Conclusion: Although circadian oscillations may be regulated by rhythmic DNA methylation, strong rhythmic associations between transcriptome and CpG methylation were not identified. This resource constitutes a transcriptomic/epigenomic atlas of skeletal muscle and regulation of circadian rhythms.
Project description:Hepatoblastomas carry few genetic alterations, and we hypothesize that epigenetic changes could be relevant to their onset. DNA methylation profile of hepatoblastomas was explored in relation to liver development using the HM450K platform. Seven paired samples of hepatoblastomas and adjacent non-tumoral livers were studied, with biologicaland results validation validated in an independent group (12 hepatoblastomas) that confirmed 1,359 differentiated methylated CpG sites (DMSs) in hepatoblastomas compared to controls, associated with 979 genes. Hepatoblastomas also exhibited a global low-level hypomethylation when compared with differentiated livers, especially at non-repetitive intergenic DNA (~55% of the hypomethylated CpGs); conversely, most of the hypermethylated CpGs were located in CpG islands. Functional analyses revealed an enrichment in signaling pathways involved in metabolism, negative regulation of cell differentiation, liver development, cancer, and the WNT pathway. Strikingly, an important overlap was observed between hepatoblastomas DMSs and the CpG sites reported to exhibit methylation changes through liver development. Genes with differential methylation were related to maintenance of undifferentiated cell state, cell transformation and tumor progression, and the methylation profile of tumors resembled that of fetal livers. Altogether, our results suggest an arrest at early stages of liver cell differentiation, in line with the hypothesis that hepatoblastoma ontogeny involves the disruption of liver development.
Project description:Using paired tumor and non-tumor lung tissues from 47 individuals we identified common changes in DNA methylation associated with the development of non-small cell lung cancer. Pathologically normal lung tissue taken at the time of cancer resection was matched to tumorous lung tissue and together were probed for methylation status using Illumina GoldenGate arrays. For each matched pair the change in methylation at each CpG was calculated (the odds ratio), and these ratios were averaged across individuals and ranked by magnitude to identify the CpGM-bM-^@M-^Ys with the greatest change in methylation associated with tumor development. Using paired tumor and non-tumor lung tissues from 47 individuals we identified common changes in DNA methylation associated with the development of non-small cell lung cancer. Pathologically normal lung tissue taken at the time of cancer resection was matched to tumorous lung tissue and together were probed for methylation status using Illumina GoldenGate arrays. For each matched pair the change in methylation at each CpG was calculated (the odds ratio), and these ratios were averaged across individuals and ranked by magnitude to identify the CpGM-bM-^@M-^Ys with the greatest change in methylation associated with tumor development.
Project description:Methylation of cytosine is an epigenetic mark involved in the regulation of transcription, usually associated with transcriptional repression. In mammals, methylated cytosines are found predominantly in CpGs but in plants non-CpG methylation (in the CpHpG or CpHpH contexts, where H is A, C or T) is also present and is associated with the transcriptional silencing of transposable elements. In addition, CpG methylation is found in coding regions of active genes. In the absence of the demethylase of lysine 9 of histone 3 (IBM1), a subset of body-methylated genes acquires non-CpG methylation. This was shown to alter their expression and affects plant development. It is not clear why only certain body-methylated genes gain non-CpG methylation in the absence of IBM1 and others do not. We described a link between CpG methylation and the establishment of methylation in the CpHpG context that explains the two classes of body-methylated genes. We provided evidence that external cytosines of CpCpG sites can only be methylated when internal cytosines are methylated and that CpCpG sites methylated in both cytosines promote spreading of methylation in the CpHpG context in genes protected by IBM1.
Project description:Mastermind-like 1 (MAML1) is a transcriptional coregulator that has been associated with early development of many systems such as neuronal, muscular, cardiovascular and urogenital. The present study aimed to explore the genome-wide effects of MAML1 on gene expression and DNA methylation in human embryonic kidney cells. RNA expression was measured using a microarray that screens approximately 36,000 transcripts, and DNA methylation was determined for 450,000 CpG sites. 225 genes were found to be differentially expressed, while 11802 CpG sites were found to be differentially methylated in MAML1-expressing cells. A subset of 211 differentially methylated loci was associated with the expression of 85 genes. Gene ontology analysis revealed that these genes are involved in the regulation of urogenital system development, cell adhesion and embryogenesis. The aim of the study was to identify genes regulated by mastermind-like pritein 1 and DNA methylation, using genome-wide approach. We assayed the effects of MAML1 overexpression, as well as knock-down, on global DNA methylation profiles in HEK293 cells. 11802 CpG sites were found to be differentially methylated in MAML1-overexpressing cells. However, no significant changes were observed by comparing HEK293_H_siControl with HEK293_H_siMAML1.