Abstract 100: Pancreatic cancer cells rely on the NADPH producing enzyme, IDH1, for adaptive survival against acute metabolic stress

Abstract

Abstract We recently demonstrated that pancreatic cancer cells adapt to low nutrient conditions and chemotherapeutic stress through an adaptive response where HuR (ELAVL1) protects cells from oxidative damage induced by metabolic stress. RNA sequencing data and a series of protein-RNA interaction assays proved that HuR stabilizes transcript levels of the NADPH producing enzyme, isocitrate dehydrogenase 1 (IDH1). HuR-knockout cells had near-complete loss of IDH1 expression (manuscript under review). In light of the fact that IDH1-null mice are particularly sensitive to oxidative damage, we hypothesize that this enzyme plays a critical role in PDA survival of acute stress. We examined the expression levels of all eight well-characterized NADPH-generating enzymes in pancreatic cancer cells in vitro, and demonstrate that only IDH1 and phosphogluconate dehydrogenase (PGD) are upregulated by >2-fold after incubation in low glucose (5 mM) for 48 hours. IDH1-knockout MiaPaCa2 cells were generated through CRISPR gene editing, such that mRNA expression was detected at <5% of control levels. ROS levels detected by DCFDA measurements were increased by 55% in IDH1-knockout cells compared to isogenic controls under normal culture conditions, with even higher levels under low glucose and chemotherapy stress for 48 hours. Additionally, IDH1-knockout cells were more sensitive to chemotherapy under both high and low glucose conditions, compared to IDH1-proficient control cells. Taken together these results suggest that IDH1 expression is important for acute antioxidant defense in pancreatic cancer cells in the face of metabolic stress, and represents a potential therapeutic target. Citation Format: Ali Vaziri-Gohar, Mahsa Zarei, Jonathan R. Brody, Jordan M. Winter. Pancreatic cancer cells rely on the NADPH producing enzyme, IDH1, for adaptive survival against acute metabolic stress [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 100. doi:10.1158/1538-7445.AM2017-100