Abstract 2176: NADPH production and redox homeostasis regulate acinar to ductal metaplasia

Abstract

Abstract Activating mutations in KRAS reprogram cellular metabolism to support continuous growth, proliferation, and survival in pancreatic cancer. However, there is little information on how KRAS-dependent alterations in metabolism change precancerous states and cancer initiation. Acinar cells can give rise to pancreatic tumors through acinar-to-ductal metaplasia (ADM), a reversible cell state that persists and progresses to neoplasia and cancer with oncogenic KRAS. During ADM, acinar cells transdifferentiate to duct-like cells, a process we hypothesized was mediated by metabolic rewiring. We performed transcriptomic analysis on acinar cells undergoing ADM and found metabolic programs are globally enhanced. Indeed, we and others have demonstrated how inhibiting metabolic pathways necessary for ADM can prevent transdifferentiation and tumorigenesis. A detailed analysis of our data revealed that the transcripts for NADPH-producing enzymes, Glucose-6-phosphate dehydrogenase (G6pd) and Malic enzyme 1 (Me1), were significant enriched during ADM. Following these results, we obtained G6pd-mutant mice and generated Me1flox/flox mice and bred them into the KC (KrasLSL-G12D/+;Ptf1aCre/+) line, resulting in KCG (KrasLSL-G12D/+;Ptf1aCre/+;G6pdmut/mut) and KCM (KrasLSL-G12D/+;Ptf1aCre/+;Me1flox/flox) mice. Interestingly, KCG and KCM mice develop ADM and neoplasia faster than their KC counterparts. We also observe that acinar cells and ADM in KCG cells have higher levels of lipid peroxidation and reactive oxygen species (ROS) both in vivo and using primary ex vivo acinar cell cultures. Thus, increased ROS levels may underlie ADM acceleration in this system. In primary acinar cell culture, we can rescue the accelerated ADM phenotype in KCG cells with the addition of antioxidants. Furthermore, we find that treatment of wild type acinar cells with buthionine sulphoximine (BSO) to deplete glutathione levels and increase ROS also accelerates ADM in culture. These results suggest that NADPH and glutathione pools are important for regulating redox levels during ADM, and that reducing these pools leads to accelerated tumorigenesis. Together, this work demonstrates new metabolic pathways driving pancreatic cancer initiation. Citation Format: Megan D. Radyk, Barbara S. Nelson, Christopher J. Halbrook, Mengrou Shan, Jonathan Alektiar, Howard C. Crawford, Yatrik M. Shah, Costas A. Lyssiotis. NADPH production and redox homeostasis regulate acinar to ductal metaplasia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2176.