Abstract B32: Restoration of beta cell mass as a synthetic lethal strategy to overcome oncogenic Kras-driven pancreatic ductal adenocarcinoma

Abstract

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a disease that remains incurable due to diagnosis at advanced stages, which renders any therapeutic intervention impracticable. The vast majority of PDAC patients develop new-onset diabetes, which often culminates in dysfunction of vital organs, leading to severe morbidity and high mortality. How PDAC development leads to diabetes is still unfolding. More than 90% of PDAC cases have an oncogenic mutation that affects the proto-oncogene Kras, mostly G12D. Using several mouse models of KrasG12D-driven PDAC, which faithfully recapitulate the human disease, we observed a massive depletion of beta cell mass, occurring even at early stages of pancreatic intraepithelial neoplasia (PanIN). This phenomenon was selective for beta cells, as PanIN or PDAC formation did not affect any other type of islet cells, including alpha and delta cells, which produce Glucagon and Somatostatin, respectively. Intriguingly, both alpha and delta cells retained their localization at the periphery of islets that are devoid of beta cells, giving rise to PanIN-like structures. Such pattern was observed when KrasG12D expression was combined with genetic inactivation of other tumor suppressor genes frequently inactivated in human PDAC, including TP53 and p16Ink4a. Lastly, we also detected depletion of beta cells and presence of remnant islets resembling PanIN in human PDAC, attesting to the clinical relevance of our findings, and further rise the attractive question of whether restoration of beta cell mass could be utilized to curb PDAC driven by oncogenic Kras. Citation Format: Thienly Nguyen, Parash Parajuli, Asrar Ahmad, Purba Singh, Sailaja Eragameddy, Gopalakrishnan Ramakrishnan, Laurence Levy, Oliver Ferrigno, Yin-Yuan Mo, Radhika Pochampally, Mohammed S Razzaque, Celine Prunier, Azeddine Atfi. Restoration of beta cell mass as a synthetic lethal strategy to overcome oncogenic Kras-driven pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr B32.