Abstract 2805: Protein oxidation in pancreatic neoplasia and cancer

Abstract

Abstract Rationale- Peroxiredoxin-1 (Prdx1) is overexpressed in pancreatic cancer patient serum and correlates with worse prognosis. Prdx1 is an important antioxidant protein whose deletion causes the formation of malignant lesions in mice. Prdx1's redox function depends on its reduction by two other Thioredoxin system members, Thioredoxin (Txn) and Sulfiredoxin (Srxn). Prdx1 may also contribute to tumorigenesis by oligomerizing and becoming a nuclear chaperone when it's overoxidized and its redox function is inhibited. Objective- Our objective was to investigate disruptions in the Txn system during pancreatic neoplasia and to determine how that affects phosphorylation of Kras effectors. Findings- Prdx1 expression was elevated and Srxn expression was reduced in pancreatic lesions of El-Kras, Pdx1-Cre/LSL-Kras (KC-Pdx1), and P48-Cre/LSL-Kras (KC-P48) mice. Txn was absent in lesions of KC-Pdx1 and KC-P48 mice but present and differentially located in EL-Kras lesions. In primary pancreatic acinar cells, oxidation of the Txn system with auranofin increased ERK and AKT phosphorylation in EL-Kras mice, but not in KC-P48 mice, indicating differential regulation of the Txn system in KC-P48 mice. This could be due to the presence of a higher molecular weight Prdx1 being present in KC-p48 mice and not in EL-Kras mice. This suggests that the effect of mutant Kras on the thioredoxin system in these two models may be different. Prdx1 and (p)ERK also interacted in vitro and inhibition of ERK and AKT phosphorylation modified the expression of Txn and Srxn in pancreatic cell lines. We also found that in human pancreatic cancer patient tissue, Prdx1 was overexpressed in pancreatic cancer as compared to adjacent normal tissue. Conclusions- The Txn system is disrupted during pancreatic neoplasia and may be associated with modified ERK and AKT regulation in Kras mutant pancreatic tissue. Citation Format: Michelle Schultz, Andrew Diaz, Sharon Smite, Brian DeCant, David Bentrem, Paul Grippo. Protein oxidation in pancreatic neoplasia and cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2805.