Project description:Ablative RT results in increased expression of CCL2 within the tumor microenvironment of pancreatic ductal adenocarcinoma (PDAC) and also increased recruitment of CD45+CD11b+Ly6Chi inflammatory monocytes/macrophages. This increase in CCL2 expression and recruitment of inflammatory monocytes/macrophages is a mechanism of resistance to the anti-tumor effects of ablative radiotherapy (RT). We used microarrays to study changes in gene expression patterns of inflammatory monocytes/macrophages sorted from the tumor microenvironment after ablative RT in a subcutenous model of pancreatic adenocarcinoma. From this, we identified 8 genes with an absolute fold change of expression equal to or greater than 2 with a false discovery rate equal to or less than 25 %.
Project description:Ablative RT results in increased expression of CCL2 within the tumor microenvironment of pancreatic ductal adenocarcinoma (PDAC) and also increased recruitment of CD45+CD11b+Ly6Chi inflammatory monocytes/macrophages. This increase in CCL2 expression and recruitment of inflammatory monocytes/macrophages is a mechanism of resistance to the anti-tumor effects of ablative radiotherapy (RT). We used microarrays to study changes in gene expression patterns of inflammatory monocytes/macrophages sorted from the tumor microenvironment after ablative RT in a subcutenous model of pancreatic adenocarcinoma. From this, we identified 8 genes with an absolute fold change of expression equal to or greater than 2 with a false discovery rate equal to or less than 25 %. A pancreatic cancer tumor cell line derived from spontaneously arising tumors in KrasLSL-G12D/+, Trp53LSL-R172H/+, Pdx1-Cre (KPC) mice was subcutaneously implanted into 8 week old female C57BL/6 and allowed to grow for 14 days. After 14 days, 4 mice received 20 Gy of radiation, and 4 mice received a sham treatment. One day post treatment, tumors were harvested, and inflammatory monocytes/macrophages were isolated using flow sorting based on a surface expression phenotype of CD45+ CD11b+ Ly6Chi. From this cell population, total RNA was extracted for creation of cDNA and hybridization on Affymetrix microarrays. From the microarrays, a set of genes associated with radiation treatment of PDAC was identified.
Project description:We found that BAP1 (BRCA1 Associated Protein-1) shows loss of heterozygosity in over 25% of pancreatic cancer patients and functions as tumor suppressor. Conditional deletion of Bap1 in murine pancreas led to genomic instability, accumulation of DNA damage, and an inflammatory response that evolved to pancreatitis with full penetrance. Concomitant expression of oncogenic KrasG12D led to malignant transformation and development of invasive and metastatic pancreatic cancer. At the molecular level, BAP1 maintains the integrity of the exocrine pancreas by regulating genomic stability and its loss confers sensitivity to radio- and platinum-based therapies.
