Abstract 3137: Elucidating the role of RNA-binding proteins in pancreatic cancer extracellular vesicle crosstalk

Abstract

Abstract Many solid tumors, including pancreatic ductal adenocarcinoma (PDAC) tumors, rely on pro-tumorigenic intercellular paracrine signaling during tumor progression. Extensive work has been done to understand paracrine signaling via cytokines, chemokines, and metabolites secreted from tumor cells, but only recent studies have begun to investigate the role of extracellular vesicles (EVs) and their cargoes in the tumor microenvironment. Studies have illustrated the ability of PDAC-derived EVs to activate and recruit pancreatic stellate cells in the tumor microenvironment; however, no work has been done in vivo to determine whether this EV uptake occurs within tumors. Additionally, little mechanistic work has been done to understand the functional consequences of EV cargo within recipient cells. Based on transcriptomic and proteomic analysis of PDAC patient-derived EVs, mRNAs and RNA-binding proteins (RBPs) are enriched within EVs. Our lab focuses on the role of RBPs in PDAC, and thus, we will utilize enhanced crosslinking immunoprecipitation to identify the RBPs within PDAC EVs and evaluate their impact on the EV transcriptome. We have successfully isolated and characterized EVs via size exclusion chromatography isolation paired with western blotting for classical EV markers, fluorescent nanoparticle tracking analysis, and transmission electron microscopy. We have also demonstrated that we can identify mRNA cargoes that are bound and unbound by RBPs. Additionally, we have optimized PKH67 labeling and detection of PDAC EVs to assess specific and preferential uptake in vitro. Further, we are establishing the validated PalmGRET bioluminescent reporter in our patient derived cell lines to track PDAC EVs in a pancreatic orthotopic mouse model. Utilizing this method, we intend to identify cell types in the microenvironment that are importing PDAC EVs and perform functional studies to understand how these cells are impacted by EV signaling. These studies will elucidate which cells in the PDAC tumor microenvironment import PDAC EVs, as well as interrogate the mechanistic role of PDAC EV crosstalk. This work will further characterize the role of RBPs in PDAC and begin to evaluate their role in a cell extrinsic manner. Citation Format: Jennifer M. Finan, Roberto Di Niro, Randall Armstrong, Jonathan R. Brody. Elucidating the role of RNA-binding proteins in pancreatic cancer extracellular vesicle crosstalk [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 3137.