Functional epigenetic approach identifies frequently methylated genes in Ewing sarcoma
EPIGENETICS
Authors: Alholle, Abdullah; Brini, Anna T.; Gharanei, Seley; Vaiyapuri, Sumathi; Arrigoni, Elena; Dallol, Ashraf; Gentle, Dean; Kishida, Takeshi; Hiruma, Toru; Avigad, Smadar; Grimer, Robert; Maher, Eamonn R.; Latif, Farida
Abstract
Using a candidate gene approach we recently identified frequent methylation of the RASSF2 gene associated with poor overall survival in Ewing sarcoma (ES). To identify effective biomarkers in ES on a genome-wide scale, we used a functionally proven epigenetic approach, in which gene expression was induced in ES cell lines by treatment with a demethylating agent followed by hybridization onto high density gene expression microarrays. After following a strict selection criterion, 34 genes were selected for expression and methylation analysis in ES cell lines and primary ES. Eight genes (CTHRC1, DNAJA4, ECHDC2, NEFH, NPTX2, PHF11, RARRES2, TSGA14) showed methylation frequencies of >20% in ES tumors (range 24-71%), these genes were expressed in human bone marrow derived mesenchymal stem cells (hBMSC) and hypermethylation was associated with transcriptional silencing. Methylation of NPTX2 or PHF11 was associated with poorer prognosis in ES. In addition, six of the above genes also showed methylation frequency of >20% (range 36-50%) in osteosarcomas. Identification of these genes may provide insights into bone cancer tumorigenesis and development of epigenetic biomarkers for prognosis and detection of these rare tumor types.
Proteomics in cerebrospinal fluid and spinal cord suggests UCHL1, MAP2 and GPNMB as biomarkers and underpins importance of transcriptional pathways in amyotrophic lateral sclerosis
ACTA NEUROPATHOLOGICA
Authors: Deckl, Patrick; Weydt, Patrick; Thal, Dietmar R.; Weishaupt, Jochen H.; Ludolph, Albert C.; Otto, Markus
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease and the proteins and pathways involved in the pathophysiology are not fully understood. Even less is known about the preclinical disease phase. To uncover new ALS-related proteins and pathways, we performed a comparative proteomic analysis in cerebrospinal fluid (CSF) of asymptomatic (n = 14) and symptomatic (n = 14) ALS mutation carriers and sporadic ALS patients (n = 12) as well as post-mortem human spinal cord tissue (controls: n = 7, ALS, n = 8). Using a CSF-optimized proteomic workflow, we identified novel (e.g., UCHL1, MAP2, CAPG, GPNMB, HIST1H4A, HIST1H2B) and well-described (e.g., NEFL, NEFH, NEFM, CHIT1, CHI3L1) protein level changes in CSF of sporadic and genetic ALS patients with enrichment of proteins related to transcription, cell cycle and lipoprotein remodeling (total protein IDs: 2303). No significant alteration was observed in asymptomatic ALS mutation carriers representing the prodromal disease phase. We confirmed UCHL1, MAP2, CAPG and GPNMB as novel biomarker candidates for ALS in an independent validation cohort of patients (n = 117) using multiple reaction monitoring. In spinal cord tissue, 292 out of 6810 identified proteins were significantly changed in ALS with enrichment of proteins involved in mRNA splicing and of the neurofilament compartment. In conclusion, our proteomic data in asymptomatic ALS mutation carriers support the hypothesis of a sudden disease onset instead of a long preclinical phase. Both CSF and tissue proteomic data indicate transcriptional pathways to be amongst the most affected. UCHL1, MAP2 and GPNMB are promising ALS biomarker candidates which might provide additional value to the established neurofilaments in patient follow-up and clinical trials.