PROJECT SUMMARY/ABSTRACT Pancreatic ductal adenocarcinoma (PDA) is a highly aggressive and lethal disease due to the poor efficacy of current therapies. Therefore, my research focuses on development of preclinical models for the identification of better therapeutic strategies. Two main distinct features of PDA are the high frequency of KRAS mutations that is poorly responsive to targeted therapies and an extensive desmoplastic tumor microenvironment (TME) composed of a dense extracellular matrix (ECM), acting as a barrier to therapy, and multiple non-neoplastic cell types including cancer-associated fibroblasts (CAF), endothelial cells, and immune cells. These two prominent features of PDA contribute to its intractability to current standard-of-care, calling for tailored targeted therapies to improve patients’ survival. As we previously reported, activation of oncogenic Kras during PDA development results in alterations to redox homeostasis and mitophagy pathways, providing evidence to support a redox-targeting approach. I will employ genetically engineered mouse models (GEMMs), organoids, and organoid transplantation models of PDA to test the potential efficacy of redox therapies, in particular mitochondrial inhibitors or ROS inducers in combination with MEKi (downstream component of Kras signaling). Our prior work has also identified heterogeneity within the population of cancer-associated fibroblasts (CAFs), each with their own distinct functions and active pathways. These fibroblasts include myofibroblastic (myCAFs), inflammatory (iCAFs) and antigen-presenting (apCAFs) CAFs. Understanding the underlying mechanisms of their active pathways is necessary for the development of therapeutic strategies to ablate tumor- promoting fibroblasts specifically. We reported that JAKi shifted the CAF subtypes towards myCAFs and suppressed tumor growth. I continue to target other active iCAF-signaling pathways through IL1R antagonism or delivery of anti-LIF antibodies in combination with immunotherapy using our GEMM models. Understanding how different types of CAFs contribute to tumor growth will provide a new avenue to develop strategies to ablate the cancer cell-promoting CAFs. To this end, we will uncover the identities and functions of these CAFs in our novel intraductally engrafted human organoid (IGO) model using a single-cell RNA sequencing approach. I will establish a series of IGO models with patient-derived organoids and use these mice to test the efficacy of co- targeting cancer cells and cancer-promoting CAFs by applying the findings from scRNA-seq analysis. Lastly, I will develop viral-induced GEMMs of PDA that can serve as a rapid platform to investigate the importance of candidate genes identified in our transcriptomic or proteomic datasets derived from our organoid and mouse models. Taken together, these multiple approaches I will employ to studying PDA, its primary driving oncogene and aberrantly altered pathways, and the surrounding microenvironment will elucidate key pathways the cancer cells require with the potential of these pathways acting as new therapeutic targets.

PROJECT NARRATIVE Pancreatic ductal adenocarcinoma (PDA) is a highly aggressive and lethal disease with an average five-year survival rate of 9%, in part due to its late detection and profound resistance to current therapies. I continue to develop more effective and novel mouse models of PDA that will enable us to study the functions of targetable genes and pathways in vivo, and help to understand the identities and functions of diverse cell types observed in human PDA. I will use these findings to design novel therapeutic strategies to eradicate both cancer cells and tumor-promoting non-cancerous fibroblasts simultaneously.