Unknown,Transcriptomics,Genomics,Proteomics

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Integrative Survival-Based Molecular Profiling of Human Pancreatic Cancer [SNP]

ABSTRACT: To perform an integrative profile of human pancreatic cancer (PDAC) to identify prognosis-significant genes and their related pathways. A concordant survival-based whole genome in silico array analysis of DNA copy number, and mRNA & micro RNA (miRNA) expression in 25 early stage PDAC was performed. A novel composite score simultaneously integrated gene expression with regulatory mechanisms to identify the signature genes with the most levels of prognosis-significant evidence. The predominant signaling pathways were determined via a pathway-based approach. Independent patient cohorts (n= 150 and 42) were then used as in vitro validation of the array findings. We find that EGFR, SRC signaling, and PI3K/AKT pathway activation are strongly linked to clinical disease progression. Furthermore, we identify two discrete subsets of pancreatic tumors characterized by either SRC or PI3K/AKT signaling that may dictate variable responses to targeted therapy. 42 human PDAC tumors and 7 non-malignant pancreas samples snap-frozen at the time of surgery were chosen. Representative H&E sections of each were evaluated by a practicing gastrointestinal pathologist to confirm diagnosis and determine relative percentage of malignant cells. Samples with tumor cell content >30% were chosen for final multi-platform analysis (N=25). Copy number analysis of Affymetrix SNP 6.0 arrays was performed for 25 PDAC samples. The HapMap270 file supplied by Affymetrix was used as the reference model for copy number inference.

ORGANISM(S): Homo sapiens

SUBMITTER: Linh Tran

PROVIDER: E-GEOD-32682 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Cyclooxygenase-2 (COX-2) is upregulated in pancreatic ductal adenocarcinomas (PDAC). However, how COX-2 promotes PDAC development is unclear. While previous studies have evaluated the efficacy of COX-2 inhibition via the use of non steroidal anti-inflammatory drugs (NSAIDs) or the COX-2 inhibitor celecoxib in PDAC models, none have addressed the cell intrinsic vs. microenvironment roles of COX-2 in modulating PDAC initiation and progression. We tested the cell intrinsic role of COX-2 in PDAC progression, using both loss-of-function and gain-of-function approaches. Cox-2 deletion in Pdx1+ pancreatic progenitor cells significantly delays the development of PDAC in mice with K-ras activation and Pten haploinsufficiency. Conversely, COX-2 over-expression promotes early onset and progression of PDAC in the K-ras mouse model. Loss of PTEN function is a critical factor in determining lethal PDAC onset and overall survival. Mechanistically, COX-2 over-expression increases P-AKT levels in the precursor lesions of Pdx1+;K-rasG12D/+;Ptenlox/+ mice in the absence of Pten LOH. In contrast, Cox-2 deletion in the same setting diminishes P-AKT levels and delays cancer progression. These data suggest an important cell intrinsic role for COX-2 in tumor initiation and progression through activation of the PI3K/AKT pathway. PDAC that is independent of intrinsic COX-2 expression eventually develops with decreased FKBP5 and increased GRP78 expression, two alternate pathways leading to AKT activation. Together, these results support a cell intrinsic role for COX-2 in PDAC development and suggest that, while anti-COX-2 therapy may delay the development and progression of PDAC, mechanisms known to increase chemoresistance through AKT activation must also be overcome. Murine mutants with pancreatic specific loss of Pten (Pten +/-) and K-ras activation (K-rasG12D) and either COX-2 over-expression (Cox-2 COE) or knockout (Cox-2 KO) under regulation of the Pdx-1 promoter developed pancreatic ductal adenocarcinoma. RNA was extracted from pancreatic tumors from individual mutants with pathology thought to closely mimic the human disease. Pancreatic tissue was subject to RNA extraction and hybridization on Affymetrix cDNA microarrays.

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Integrative Survival-Based Molecular Profiling of Human Pancreatic Cancer [SNP]

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