Abstract 991: Unraveling the role of nicotinamide adenine dinucleotide precursors in pancreatic cancer biology
Authors: Faith Nakazzi, Mehrad Zarei, Hallie J. Graor, Alexander W. Loftus, Omid Hajihassanni, Jordan M. Winter
Journal: Cancer Research (2024)

Abstract Introduction: Pancreatic cancer has the lowest 5-year survival rates among all cancers because of the challenges with early detection, its aggressive nature, and resistance to chemotherapy; this makes prevention a promising approach for reducing related mortalities. The disease is predominantly diagnosed in individuals over 60, suggesting that age-related physiological decline impacts its onset; therefore, delaying aging hallmarks may delay its onset. Nicotinamide dinucleotide (NAD+) precursors may hold a unique advantage over other geroprotectors because they target multiple aging hallmarks. Heron, we investigated how NAD+ supplementation impacts normal human pancreatic ductal epithelial cells (HPDE) under stress as a surrogate for cancer prevention in vitro. We also examined the paradoxical impact of NAD+ precursor supplementation on pancreatic cancer growth during chemotherapy. Methods: In vitro, we mimicked age-related NAD+ decline in the media. We stressed HPDE cells under these conditions and evaluated the effect of supplementation with the NAD+ precursor, Nicotinamide mononucleotide (NMN). We assessed cell viability using the PicoGreen assay, mitochondrial function, and reactive oxygen species (ROS) using the Seahorse XF Analyzer and the mitoSox kit, respectively, DNA repair and DNA damage using a western blot for Poly ADP ribose (PAR) and gamma H2AX, respectively, and SIRT3 expression was determined using a western blot. To evaluate the impact of NAD+ supplementation on pancreatic cancer cells, we treated pancreatic cancer cells with NMN and oxaliplatin. We then assessed the mitochondrial function, ROS levels, DNA damage, and repair. We implanted MiaPaCa-2 xenografts into athymic nude mice and treated them daily with 300mg/Kg of NMN and biweekly 5mg/kg of Oxaliplatin. Results: Experiments revealed that NMN is not toxic to HPDE cells, even at high concentrations. There was increased cell survival of HPDE cells under stress (nutrient deprivation and alkylating agents) following NMN supplementation. We also noted reduced ROS levels, increased SIRT3 expression, and PARylation. Pancreatic cancer cells were less sensitive to Oxaliplatin following NMN supplementation and showed an increased oxygen consumption rate, increased PARylation, and reduced ROS levels. There was reduced sensitivity to oxaliplatin treatment in the mice with MiaPaCa-2 xenografts treated with NMN. Conclusion: These findings demonstrate a cytoprotective role of NAD+ precursor supplementation in normal pancreatic ductal epithelial cells, with implications for possible cancer prevention. NAD+ supplementation also rescued cancer cells under cytotoxic stress, meaning that geroprotectors like NMN, in conjunction with chemotherapy, may unintentionally promote cancer progression. Future studies will directly test NAD+ precursor supplementation in genetically engineered pancreatic cancer models. Citation Format: Faith Nakazzi, Mehrad Zarei, Hallie J. Graor, Alexander W. Loftus, Omid Hajihassanni, Jordan M. Winter. Unraveling the role of nicotinamide adenine dinucleotide precursors in pancreatic cancer biology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 991.