Epigenetics!

A genome-wide search for epigenetically regulated genes in zebra finch using MethylCap-seq and RNA-seq
Learning and memory formation are known to require dynamic CpG (de)methylation and gene expression changes. Here, we aimed at establishing a genome-wide DNA methylation map of the zebra finch genome, a model organism in neuroscience, as well as identifying putatively epigenetically regulated genes. RNA- and MethylCap-seq experiments were performed on two zebra finch cell lines in presence or absence of 5-aza-2′-deoxycytidine induced demethylation. First, the MethylCap-seq methodology was validated in zebra finch by comparison with RRBS-generated data. To assess the influence of (variable) methylation on gene expression, RNA-seq experiments were performed as well. Comparison of RNA-seq and MethylCap-seq results showed that at least 357 of the 3,457 AZA-upregulated genes are putatively regulated by methylation in the promoter region, for which a pathway analysis showed remarkable enrichment for neurological networks. A subset of genes was validated using Exon Arrays, quantitative RT-PCR and CpG pyrosequencing on bisulfite-treated samples. To our knowledge, this study provides the first genome-wide DNA methylation map of the zebra finch genome as well as a comprehensive set of genes of which transcription is under putative methylation control.

A genome-wide search for eigenetically regulated genes in zebra finch using MethylCap-seq and RNA-seq. Steyaert, Sandra; Diddens, Jolien; Galle, Jeroen; De Meester, Ellen; De Keulenaer, Sarah; Bakker, Antje; Sohnius-Wilhelmi, Nina; Frankl-Vilches, Carolina; Van der Linden, Annemie; Van Criekinge, Wim; Berghe, Wim Vanden; De Meyer, Tim. SCIENTIFIC REPORTS, 6 10.1038/srep20957 FEB 11 2016

Methyl-CpG-binding domain sequencing reveals a prognostic methylation signature in neuroblastoma
Accurate assessment of neuroblastoma outcome prediction remains challenging. Therefore, this study aims at establishing novel prognostic tumor DNA methylation biomarkers. In total, 396 low-and high-risk primary tumors were analyzed, of which 87 were profiled using methyl-CpG-binding domain (MBD) sequencing for differential methylation analysis between prognostic patient groups. Subsequently, methylation-specific PCR (MSP) assays were developed for 78 top-ranking differentially methylated regions and tested on two independent cohorts of 132 and 177 samples, respectively. Further, a new statistical framework was used to identify a robust set of MSP assays of which the methylation score (i.e. the percentage of methylated assays) allows accurate outcome prediction. Survival analyses were performed on the individual target level, as well as on the combined multimarker signature. As a result of the differential DNA methylation assessment by MBD sequencing, 58 of the 78 MSP assays were designed in regions previously unexplored in neuroblastoma, and 36 are located in non-promoter or non-coding regions. In total, 5 individual MSP assays (located in CCDC177, NXPH1, lnc-MRPL3-2, lnc-TREX1-1 and one on a region from chromosome 8 with no further annotation) predict event-free survival and 4 additional assays (located in SPRED3, TNFAIP2, NPM2 and CYYR1) also predict overall survival. Furthermore, a robust 58-marker methylation signature predicting overall and event-free survival was established. In conclusion, this study encompasses the largest DNA methylation biomarker study in neuroblastoma so far. We identified and independently validated several novel prognostic biomarkers, as well as a prognostic 58-marker methylation signature.

Link to full text

Methyl-CpG-binding domain sequencing reveals a prognostic methylation signature in neuroblastoma. Decock, Anneleen; Ongenaert, Mate; Cannoodt, Robrecht; Verniers, Kimberly; De Wilde, Bram; Laureys, Genevieve; Van Roy, Nadine; Berbegall, Ana P.; Bienertova-Vasku, Julie; Bown, Nick; Clement, Nathalie; Combaret, Valerie; Haber, Michelle; Hoyoux, Claire; Murray, Jayne; Noguera, Rosa; Pierron, Gaelle; Schleiermacher, Gudrun; Schulte, Johannes H.; Stallings, Ray L.; Tweddle, Deborah A.; De Preter, Katleen; Speleman, Frank; Vandesompele, Jo. ONCOTARGET, 7 (2):1960-1972; JAN 12 2016

Evaluation of an Epigenetic Profile for the Detection of Bladder Cancer in Patients with Hematuria
Purpose: Many patients enter the care cycle with gross or microscopic hematuria and undergo cystoscopy to rule out bladder cancer. Sensitivity of this invasive examination is limited, leaving many patients at risk for undetected cancer. To improve current clinical practice more sensitive and noninvasive screening methods should be applied.

Materials and Methods: A total of 154 urine samples were collected from patients with hematuria, including 80 without and 74 with bladder cancer. DNA from cells in the urine was epigenetically profiled using 2 independent assays. Methylation specific polymerase chain reaction was performed on TWIST1. SNaPshot (TM) methylation analysis was done for different loci of OTX1 and ONECUT2. Additionally all samples were analyzed for mutation status of TERT (telomerase reverse transcriptase), PIK3CA, FGFR3 (fibroblast growth factor receptor 3), HRAS, KRAS and NRAS.

Results: The combination of TWIST1, ONECUT2 (2 loci) and OTX1 resulted in the best overall performing panel. Logistic regression analysis on these methylation markers, mutation status of FGFR3, TERT and HRAS, and patient age resulted in an accurate model with 97% sensitivity, 83% specificity and an AUC of 0.93 (95% CI 0.88-0.98). Internal validation led to an optimism corrected AUC of 0.92. With an estimated bladder cancer prevalence of 5% to 10% in a hematuria cohort the assay resulted in a 99.6% to 99.9% negative predictive value.

Conclusions: Epigenetic profiling using TWIST1, ONECUT2 and OTX1 results in a high sensitivity and specificity. Accurate risk prediction might result in less extensive and invasive examination of patients at low risk, thereby reducing unnecessary patient burden and health care costs.

Evaluation of an Epigenetic Profile for the Detection of Bladder Cancer in Patients with Hematuria. van Kessel, Kim E. M.; Van Neste, Leander; Lurkin, Irene; Zwarthoff, Ellen C.; Van Criekinge, Wim. JOURNAL OF UROLOGY, 195 (3):601-607; 10.1016/j.juro.2015.08.085 MAR 2016