Abstract 1332: Adar1 impacts pancreatic homeostasis and pancreatic tumor biology

Abstract Adenosine-to-Inosine (A-to-I) RNA editing is mediated by Adenosine deaminase acting on RNA (Adar) enzymes. The resulting A-to-I edit in RNA alters its post-transcriptional processing making Adar1 a critical regulator of gene expression. In line with its role in gene regulation, Adar1 has been implicated in development and organogenesis. We investigated the role of Adar1 in pancreatic development and homeostasis, and observed that though Adar1 is not required for pancreatic development, it is essential for pancreatic homeostasis. We observed that loss of Adar1 can stimulate a Mavs-mediated innate immune pathway and results in influx of immune cells in the pancreas. Pancreatic tumors are notorious for their immunosuppressive microenvironment. Since loss of Adar1 can activate a Mavs-mediated innate immune pathway, we next investigated the role of ADAR1 in human pancreatic ductal adenocarcinoma cell lines. We developed a bioinformatics pipeline, Cancer RSNV (RNA Single Nucleotide Variant) Identifier and Annotator (CRIDA) to identify A-to-I RNA edits in pancreatic cancer and observed wide-spread ADAR1-mediated RNA editing in pancreatic cancer cells. We analyzed genes that are differentially regulated between ADAR1 knockdown and control cells, and observed a differential immune signaling. Together, our data suggests that Adar1 is important for pancreatic homeostasis and tumor biology. Citation Format: Dhwani Rupani, Robert Cowan, Chris Gates, Florencia McAllister, Andrew Rhim. Adar1 impacts pancreatic homeostasis and pancreatic tumor biology [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 1332.