Abstract PO-061: The role of Cathepsin E expression in pancreatic ductal adenocarcinoma tumorigenesis

Abstract

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) has a dismal 5-year survival rate of 10% due to a lack of early detection and effective treatments. Aspartic protease Cathepsin E (CTSE) expression is increased early in PDAC, but its role in tumorigenesis is unknown. We hypothesize that high CTSE expression promotes proliferation, invasion, inhibition of apoptosis, and the secretion of cancer-associated cytokines in PDAC. Methods: Human PDAC cell lines (Mpanc96, Panc-1, and Miapaca2) were engineered to express high levels of CTSE. Cell proliferation, invasion, and apoptosis were analyzed and compared to control cell lines expressing low levels of CTSE. Cells were treated with aspartic protease inhibitors (Pepstatin A and Ritonavir) and monitored for proliferation (24 - 72 hours) and invasion (48 hours). Apoptosis was measured using propidium iodide and analyzed via flow cytometry. Conditioned media from cells was collected (72 hours) after treatment to assess differential secretion of cancer-associated cytokines using a cytokine array. Results: Proliferation was not affected by the overexpression of CTSE; however, inhibition of CTSE slowed proliferation in the Panc-1 and MiaPaca2, but not Mpanc96 cells. CTSE inhibitors promoted invasion of Mpanc96 and Panc-1, but not Miapaca2 cells, regardless of CTSE levels. Apoptosis was not significantly different between the cell lines treated with the aspartic protease inhibitors compared to controls. Increased expression of CTSE induced the secretion of various cytokines such as epithelial neutrophil-activating protein 78 (ENA-78), a chemokine expressed in inflammatory pancreatic disorders. Treatment with the inhibitor Pepstatin A decreased ENA-78 secretion. Conclusions: CTSE levels does not appear to affect proliferation or apoptosis; however, inhibition of CTSE increased cell invasion and resulted in altered cytokine secretion. Further studies examining how CTSE influences invasiveness, and cytokine secretion may create new opportunities for developing effective therapies for PDAC. Citation Format: Ericka Velez-Bonet, Sabrina Kaul, Corbin Pontious, Marcus Hong, Kelly Dubai, Zobeida Cruz-Monserrate. The role of Cathepsin E expression in pancreatic ductal adenocarcinoma tumorigenesis [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PO-061.