Quantitative Analysis of PPARD mRNA-Seq Transcriptomes of Mouse KRAS Mutant Pancreatic Tissues by Next Generation Sequencing (NGS)

Pancreatic cancer is the most highly lethal disease with an increasing incidence. Accumulating evidence shows that as an initiating event of pancreatic tumorigenesis, mutant KRAS requires additional factors to promote pancreatic cancer progression. Peroxisome proliferator-activated receptor-delta/beta (PPAR-d) is a ligand-activating transcription factor that modulates many critical cellular functions and is upregulated in human pancreatic cancer tissues. To study PPAR-d's effects on mutant KRAS-initiated pancreatic tumorigenesis, we have generated a novel transgenic mouse model with simultaneously targeted PPAR-d overexpression and KrasG12D mutation (KRASmu) in pancreatic epithelial cells (called KC/Pd mice). Our preliminary data showed that PPAR-d ligand GW501516 strongly promoted pancreatic tumorigenesis in KRASmu mice (KC), and PPAR-d upregulation dramatically enhanced these effects in KC/Pd mice. However, molecular mechanisms by which PPAR-d and its synthetic ligand GW501516 promote KRASmu-initiated pancreatic tumorigenesis remains largely unknown. We have therefore performed genome-wide mRNA seq profiling analysis for pancreatic tissues from KC [WT] and KC/Pd (PD) mice fed GW501516 diet to discover the critical genes/pathways directly regulated by PPAR-d overactivation that accelerate pancreatic cancer progression. Pancreatic tissues of GW-treated KC/Pd (PD-GW) and KC (WT-GW) mice had distinctive differential expression patterns with 1498 differentially expressed genes (DEGs) according to a cut-off of p(Adj)<.05, including 709 upregulated DEGs and 789 downregulated DEGs. Furthermore, Gene set enrichment analyses of these 1498 DEGs using the ?Hallmark gene sets? category showed that the top enriched pathways included IL6-JAK-STAT3, inflammatory response, and KRAS signaling. Thus, the RNA-seq profiling analyses provide us important clues for molecular mechanisms by which PPAR-d overactivation promotes pancreatic cancer progression. The mRNA-seq transcriptome profile of mouse pancreatic tissues from KC (WT) mice and KC/PD (PD) mice fed a GW501516 diet for 3 days (3 mice per group) was generated by deep sequencing using Illumina HiSeq3000