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Combined Genome and Transcriptome Sequencing to Identify Allelic Selection in Epithelial Ovarian Cancer

ABSTRACT: Identifying genes where a variant allele is preferentially expressed in tumors could lead to a better understanding of cancer biology and optimization of targeted therapy. However, tumor sample heterogeneity complicates standard approaches for detecting preferential allele expression. We therefore developed a novel approach combining genome and transcriptome sequencing data from the same sample that corrects for sample heterogeneity and identifies significant preferentially expressed alleles. We applied this analysis to epithelial ovarian cancer samples consisting of matched primary ovary and peritoneum and lymph node metastasis. We find that preferentially expressed variant alleles include germline and somatic variants, are shared at a relatively high frequency between patients and are in gene networks known to be involved in cancer processes. Analysis at a patient level identifies patient-specific preferentially expressed alleles in genes that are targets for known drugs. Analysis at a site level identifies patterns of site specific preferential allele expression with similar pathways being impacted in the primary and metastasis sites. We conclude that genes with preferentially expressed variant alleles can act as cancer drivers and that targeting those alleles could lead to new therapeutic strategies.

ORGANISM(S): Homo sapiens

PROVIDER: GSE75935 | GEO | 2015/12/12

SECONDARY ACCESSION(S): PRJNA305745

REPOSITORIES: GEO

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Combined Genome and Transcriptome Sequencing to Identify Allelic Selection in Epithelial Ovarian Cancer

Project description:Identifying genes where a variant allele is preferentially expressed in tumors could lead to a better understanding of cancer biology and optimization of targeted therapy. However, tumor sample heterogeneity complicates standard approaches for detecting preferential allele expression. We therefore developed a novel approach combining genome and transcriptome sequencing data from the same sample that corrects for sample heterogeneity and identifies significant preferentially expressed alleles. We applied this analysis to epithelial ovarian cancer samples consisting of matched primary ovary and peritoneum and lymph node metastasis. We find that preferentially expressed variant alleles include germline and somatic variants, are shared at a relatively high frequency between patients and are in gene networks known to be involved in cancer processes. Analysis at a patient level identifies patient-specific preferentially expressed alleles in genes that are targets for known drugs. Analysis at a site level identifies patterns of site specific preferential allele expression with similar pathways being impacted in the primary and metastasis sites. We conclude that genes with preferentially expressed variant alleles can act as cancer drivers and that targeting those alleles could lead to new therapeutic strategies. Three cancer patients, three tumor samples per patient from different sites, two normal tissue samples from two different patients, four cell lines.

2015-12-12 | E-GEOD-75935 | biostudies-arrayexpress

Natural WNT signaling variant potently synergizes with Cdkn2ab loss in skin carcinogenesis.

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4T1 RNA-Seq

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Project description:Alzheimers disease (AD) is the most common form of dementia in the elderly with no cure. Although huge efforts have been made to develop drugs for AD, most programs aimed for disease-modifying therapies have failed. Possible reasons for the high failure rate include insufficient understanding of mechanisms underlying AD pathogenesis. The C allele of rs11136000 variant in the clusterin (CLU) gene represents the third strongest known genetic risk factor for late-onset AD. However, whether the CLU rs11136000 SNP is functional and what are molecular mechanisms underlying the risk effect of the CLU variant remain unknown. In this study, we identified the CLU rs11136000 SNP as a functional variant by CRIPSR/Cas9 knockout of the SNP. Moreover, by switching the risk C and the protective T alleles using CRISPR/Cas9 editing, we generated isogenic iPSCs with different alleles of the CLU rs11136000 SNP. Astrocytes derived from isogenic iPSCs carrying the C or T allele exhibited different CLU expression and differential inflammatory response. C/C astrocytes carrying two C alleles expressed higher level of CLU and exhibited elevated interferon (IFN) response and CXCL10 expression upon TNFalpha/IL1beta treatment. Furthermore, using human iPSC-derived astrocytes and OPCs co-cultured on nanofibers, we demonstrated that elevated CXCL10 expression in C/C astrocytes induced by TNFalpha/IL1beta led to inhibition of OPC proliferation and myelination. Our study uncovers a mechanism underlying reduced white matter integrity observed in the CLU rs11136000 risk C allele carriers. This knowledge could help us to design more effective strategies to treat AD by targeting IFN response and CXCL10 that are upstream of myelination deficits, an early event in AD pathogenesis that proceeds before cognitive decline.

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2014-06-11 | E-GEOD-53779 | biostudies-arrayexpress

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