Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Expression data from SDH-disabled GIST

ABSTRACT: Pediatric GIST commonly harbors a disabled succinate dehydrogenase complex (SDH), which yields tumors with highly conserved genomes but characteristic epigenomic signatures. Mysteriously, nearly half of such SDH-deficient GIST, including tumors from Carney Triad patients, lack identifiable mutations in SDH component genes and genes required for complex assembly (SDHA, SDHB, SDHC, SDHD, SDHAF, termed SDHx). Genomic sequencing coupled with DNA methylation and transcriptional profiling have exposed SDHC promoter-specific CpG island epimutation and concomitant gene silencing in the majority of SDHx-WT GIST. We performed whole genome expression profiling on 20 FFPE dSDH GIST tumors using Affymetrix U133P2 arrays which contain >54K gene target probesets. Included here were data from 7 SDHx-w.t. and 13 SDHx mutants that passed array QC.

ORGANISM(S): Homo sapiens

SUBMITTER: Yuelin Zhu

PROVIDER: E-GEOD-56670 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Recurrent epimutation of SDHC in gastrointestinal stromal tumors.

Killian J Keith JK Miettinen Markku M Walker Robert L RL Wang Yonghong Y Zhu Yuelin Jack YJ Waterfall Joshua J JJ Noyes Natalia N Retnakumar Parvathy P Yang Zhiming Z Smith William I WI Killian M Scott MS Lau C Christopher CC Pineda Marbin M Walling Jennifer J Stevenson Holly H Smith Carly C Wang Zengfeng Z Lasota Jerzy J Kim Su Young SY Boikos Sosipatros A SA Helman Lee J LJ Meltzer Paul S PS

Science translational medicine 20141201 268

Succinate dehydrogenase (SDH) is a conserved effector of cellular metabolism and energy production, and loss of SDH function is a driver mechanism in several cancers. SDH-deficient gastrointestinal stromal tumors (dSDH GISTs) collectively manifest similar phenotypes, including hypermethylated epigenomic signatures, tendency to occur in pediatric patients, and lack of KIT/PDGFRA mutations. dSDH GISTs often harbor deleterious mutations in SDH subunit genes (SDHA, SDHB, SDHC, and SDHD, termed SDHx) ...[more]

PMID: 25540324

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Project description:Purpose: Due to the rarity of Merkel Cell Carcinoma (MCC), prospective clinical trials have not been practical. This study seeks to identify biomarkers to differentiate between patients with a good and poor prognosis. Methods: Patients were stratified into good, moderate or poor prognosis. Merkel cell carcinoma (MCC) patients were stratified into one of three groups based upon status 24 months following treatment. Poor prognosis patients either presented with or progressed to distant metastasis. Patients with favorable prognosis had local disease presentation with no subsequent recurrence or nodal disease at presentation with no progression during follow-up of longer than 24 months. Moderate prognosis had recurrent local disease, development of nodal metastasis, or nodal disease at presentation with no progression during follow-up of fewer than 24 months. Using ArcturusXT Laser Capture Microdissection (Molecular Devices), tumor cells were isolated from the specific areas of interest. The captured tumor tissue was subjected to RNA extraction using the Invitrogen PureLinkM-bM-^DM-" FFPE RNA Isolation Kit. The extracted RNA was analyzed for integrity with the Agilent Bioanalyzer then amplified and hybridized to Affymetrix GeneChip Human Exon 1.0 ST arrays using the NuGEN WT- OvationM-bM-^DM-" FFPE System. Results: A total of 191 genes showed significant differential expression (pM-bM-^IM-$0.05 and 1.5-fold cutoff) between the different between the good and poor prognosis groups. Keratin 20 (KRT20) and Neurofilament protein (NEFM) have been identified in previous studies as proteins of interest in MCC. Our study showed these genes to be significantly upregulated in patients with a poor prognosis. Of interest, phospholipase A2, group X was upregulated in poor responders. Phospholipases liberate arachidonic acid from cellular membranes which can be metabolized to eicosanoids through three major pathways: the cyclooxygenase (COX), the lipoxygenase (LOX) and the cytochrome P450 monooxygenase pathways. This pathway has been implicated in several cancers. Conclusions: The study identified genes with a previous association with MCC as well as some novel genes. These genes provide the basis for further research into possible biomarkers that will enable the differentiation between patients with a good and poor prognosis. Using laser capture microdissection, tumor cells of patients with a good (n=5), moderate (n=3), and poor prognosis (n=7) were isolated from paraffin embedded archival tissue of 15 patients with Merkel cell carcinoma. Affymetrix Human Exon 1.0ST microarrays were utilized to compare gene expression signatures from good and poor prognosis patients.

Project description:The classical sacrococcygeal chordoma tumor presents with a typical morphology of lobulated myxoid tumor tissue with cords, strands and nests of tumor cells consisting of small non-vacuolated cells, intermediate cells with a wide range of vacuolization and large heavily vacuolated (physaliferous) cells. Because of its rare incidence, lack of suited model systems and technical limitations analysis was only performed on bulk tumor mass neglecting its heterogeneous composition. We aimed at elucidating the differences between small non-vacuolated and large physaliferous cells on the genomic and transcriptomic level. Secondly, we intended to clarify whether the observed cell types are derived from genetically distinct clones or rather represent different phenotypes. Using the chordoma cell line MUG-Chor1 we monitored morphological changes via time lapse experiments. We isolated pure fractions of each phenotype by means of laser microdissection or micromanipulation allowing phenotype-specific analysis. Pools of 100 cells each were genetically profiled after whole genome amplification by array comparative genomic hybridization. For expression analysis 20 cells each were subjected to whole transcriptom amplification, forwarded to RNA microarray analysis and qRT-PCR. Time lapse analysis unveiled small non-vacuolated cells to develop into large physaliferous cells via intermediate cells containing an increasing amount of vacuoles. Furthermore, we showed small and large physaliferous cells to proliferate at the same rate but intermediate cells to be the most proliferating cell phenotype. Small non-vacuolated and large physaliferous cells showed identical copy number variations. Despite their obvious morphological disparities we detected only modest changes in over all gene expression. However, verification of candidate genes yielded significant up-regulation of ALG11 (700-fold), PPP2CB (18.6-fold), and UCHL3 (18.7-fold) in large physaliferous cells. Of two different cell types (large and small MUG-Chor1 cells) we analysed each in triplicates. In total 6 cell pools were analysed.

Dataset Information

Expression data from SDH-disabled GIST

Publications

Recurrent epimutation of SDHC in gastrointestinal stromal tumors.

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