Project description:mRNA expression data from RalGAPβ-deficient human pancreatic ductal adenocarcinoma cells (MIA PaCa-2), MIA PaCa-2 parental cells, and MIA PaCa-2 control cells
Project description:Transcriptional profiling of Mia PaCa 2 cells treated with 5-Aza for 96 h. Relative abundance to untreated control cells was used to estimate the effect of DNA demethylation on the expression of the RNAs. Two-condition experiment, 5-Aza-treated vs. untretated Mia PaCa 2 cells. Biological replicates: 2. Technical replicates: 2.
Project description:A variety of cancers utilize RAS-regulated signaling pathways to promote oncogenic phenotypes. A widely studied example is pancreatic cancer, where mutant KRAS signaling leads to activation of MEK/ERK kinases and downstream signaling which promotes oncogenic mechanisms, including cell proliferation. Importantly, ERK inhibitors have shown efficacy in some cancer clinical trials. Previously, others have studied the effects of the related kinases TBK1 and IKKε in pancreatic cancer where they have been shown to promote cell survival. Here, we show that RAS/MAPK signaling promotes expression of IKKε through control of protein stability and not through control of RNA levels. RNAseq analysis indicate that TBK1 and IKKε contribute to the expression of a subset of ERK-regulated genes. Potentially related to the effects on IKKε, proteomic analysis reveals that ERK functions to stabilize a relatively large set of proteins independent of RNA regulation. Knockdown of IKKε and TBK1 individually does not affect growth of MIA PaCa-2 pancreatic cancer cells, but dual knockdown significantly inhibits MIA PaCa-2 growth which is mediated through cell death. Concurrent silencing or inhibition of both TBK1 and IKKε also reduces tumor sphere growth in MIA PaCa-2 cells, correlating with a loss of stemness pathways found with RNAseq. The data suggest the importance of regulation of IKKε by ERK in pancreatic cancer cells and of the combined oncogenic activity of TBK1 and IKKε.
Project description:The molecular mechanisms underlying exceptional radioresistance in pancreatic cancer remain elusive. In the present study, we established a stable radioresistant pancreatic cancer cell line MIA PaCa-2-R by exposing the parental MIA PaCa-2 cells to fractionated ionizing radiation (IR). Systematic proteomics and bioinformatics comparison of protein expression in MIA PaCa-2 and MIA PaCa-2-R cells revealed that several growth factor- and cytokine-mediated pathways, including the OSM/STAT3, PI3K/AKT and MAPK/ERK pathways, were activated in the radioresistant cells, leading to enhanced cell migration, invasion and epithelial-mesenchymal transition (EMT), and inhibition of apoptosis. We focused functional analysis on one of the most upregulated proteins in the radioresistant cells, CD73, which is a cell surface protein that is overexpressed in a variety types of cancer. Ectopic overexpression of CD73 in the parent cells resulted in radioresistance and conferred resistance to IR-induced apoptosis. Knockdown of CD73 resensitized the radioresistant cells to IR and IR-induced apoptosis. The effect of CD73 on radioresistance and apoptosis is independent of the enzymatic activity of CD73. Further studies suggest that CD73 confers acquired radioresistance in pancreatic cancer cells at least in part through inactivating proapoptotic protein BAD via phosphorylation of BAD at Ser-136. Furthermore, we found that knockdown of CD73 in the radioresistant cells alone reverted the gene expression and phenotype of the radioresistant cells from those of mesenchymal-like cells to the ones of epithelial cells, demonstrating that CD73 upregulation is required for maintaining EMT in the radioresistant cells. Our results support the notion that the enhanced growth factor/cytokine signaling that promotes epithelial-mesenchymal plasticity, and acquisition of cancer stem-like cell properties contributes to acquired radioresistance in the residual surviving cells after fractionated irradiation, and that CD73 is a novel downstream factor of those enhanced signaling and acts to confers acquired radioresistance and maintains EMT in the radioresistant pancreatic cancer cells.
Project description:A variety of cancers utilize RAS-regulated signaling pathways to promote oncogenic phenotypes. A widely studied example is pancreatic cancer, where mutant KRAS signaling leads to activation of MEK/ERK kinases and downstream signaling which promotes oncogenic mechanisms, including cell proliferation. Importantly, ERK inhibitors have shown efficacy in some cancer clinical trials. Previously, others have studied the effects of the related kinases TBK1 and IKKε in pancreatic cancer where they have been shown to promote cell survival. Here, we show that RAS/MAPK signaling promotes expression of IKKε through control of protein stability and not through control of RNA levels. RNAseq analysis indicate that TBK1 and IKKε contribute to the expression of a subset of ERK-regulated genes. Potentially related to the effects on IKKε, proteomic analysis reveals that ERK functions to stabilize a relatively large set of proteins independent of RNA regulation. Knockdown of IKKε and TBK1 individually does not affect growth of MIA PaCa-2 pancreatic cancer cells, but dual knockdown significantly inhibits MIA PaCa-2 growth which is mediated through cell death. Concurrent silencing or inhibition of both TBK1 and IKKε also reduces tumor sphere growth in MIA PaCa-2 cells, correlating with a loss of stemness pathways found with RNAseq. The data suggest the importance of regulation of IKKε by ERK in pancreatic cancer cells and of the combined oncogenic activity of TBK1 and IKKε.