angiogenin and Carcinoma--Pancreatic-Ductal

Pancreatic ribonuclease (RNase) is a secreted enzyme critical for host defense. We discover an intrinsic RNase function, serving as a ligand for epidermal growth factor receptor (EGFR), a member of receptor tyrosine kinase (RTK), in pancreatic ductal adenocarcinoma (PDAC). The closely related bovine RNase A and human RNase 5 (angiogenin [ANG]) can trigger oncogenic transformation independently of their catalytic activities via direct association with EGFR. Notably, high plasma ANG level in PDAC patients is positively associated with response to EGFR inhibitor erlotinib treatment. These results identify a role of ANG as a serum biomarker that may be used to stratify patients for EGFR-targeted therapies, and offer insights into the ligand-receptor relationship between RNase and RTK families.

Topics: Animals; Binding Sites; Biomarkers; Carcinoma, Pancreatic Ductal; Cattle; Cell Line, Tumor; ErbB Receptors; Erlotinib Hydrochloride; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; HeLa Cells; Humans; Mice; Neoplasm Transplantation; Pancreatic Neoplasms; Ribonuclease, Pancreatic; Signal Transduction

Despite existing chemotherapy and surgical resection strategies, pancreatic cancer is one of the major causes of mortality in the United States with a 5-year mean survival rate of less than 5%. The activation of the urokinase-type plasminogen activator receptor-urokinase-type plasminogen activator (uPAR-uPA) system in the development of pancreatic ductal adenocarcinoma has been well established. In the present study, we used 2 pancreatic cancer cell lines, MIA PaCa-2 and PANC-1 to show the effects of uPAR and uPA downregulation. From the results, we observed that RNAi expressing plasmids efficiently downregulated mRNA and protein expression of uPAR and uPA. In vitro and in vivo angiogenic assays revealed a significant decrease in the angiogenic potential of MIA PaCa-2 and PANC-1 cells that were downregulated for both uPAR and uPA. From the angiogenesis antibody array analysis, we observed that the simultaneous downregulation of uPAR and uPA resulted in the downregulation of angiogenin and overexpression of RANTES. Further, FACS analysis showed that the simultaneous downregulation of uPAR and uPA caused the accumulation of cells in the sub-G(0/1) phase in both MIA PaCa-2 and PANC-1 cells. In addition, Western blot analysis revealed that downregulation of uPAR and uPA caused the activation of caspase 8 and CAD, which is indicative of apoptosis, and in vivo TUNEL assay confirmed these results. Finally, we observed the nuclear localization of uPA and that uPA interacts with the transcription factor Lhx-2. Taken together, the results of the present study show that the targeting of the uPAR-uPA system has therapeutic potential.

Topics: Animals; Apoptosis; Aspartate Carbamoyltransferase; Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing); Carcinoma, Pancreatic Ductal; Caspase 8; Cell Line, Tumor; Chemokine CCL5; Dihydroorotase; Gene Targeting; Homeodomain Proteins; Humans; LIM-Homeodomain Proteins; Mice; Neoplasm Invasiveness; Neovascularization, Pathologic; Pancreatic Neoplasms; Receptors, Urokinase Plasminogen Activator; Ribonuclease, Pancreatic; RNA Interference; RNA, Small Interfering; Transcription Factors; Urokinase-Type Plasminogen Activator; Xenograft Model Antitumor Assays