PROJECT SUMMARY/ABSTRACT Despite significant recent advances in precision medicine, pancreatic ductal adenocarcinoma (PDAC) remains near-uniformly lethal. While the most frequent genomic alterations in PDAC are not presently druggable and conventional therapies are often ineffective in this disease, immune-modulatory therapies hold promise to meaningfully improve outcomes for PDAC patients. Development of such therapies requires an improved understanding of the immune evasion mechanisms that characterize the PDAC microenvironment, including frequent exclusion of antineoplastic T cells and abundance of immune-suppressive myeloid cells. We recently found that cancer cell-intrinsic glutamic-oxaloacetic transaminase 2 (GOT2) shapes the immune microenvironment to suppress antitumor immunity. Mechanistically, we found that GOT2 functions beyond its established role in the malate-aspartate shuttle and promotes the transcriptional activity of nuclear receptor PPARd, facilitated by direct binding to PPARd ligand arachidonic acid. While GOT2 in PDAC cells is dispensable for cancer cell proliferation in vivo, GOT2 loss results in T cell-dependent suppression of tumor growth, and genetic or pharmacologic PPARd activation restores PDAC progression in the GOT2-null context. This cancer cell-intrinsic GOT2-PPARd axis promotes spatial restriction of both CD4 and CD8 T cells from the tumor microenvironment, and fosters the immune-suppressive phenotype of tumor-infiltrating myeloid cells. Our results to date demonstrate a non-canonical function for an established mitochondrial enzyme in transcriptional regulation of immune evasion, and here we propose to exploit this novel GOT2-PPARd axis to promote a productive antitumor immune response with the following specific aims. Aim 1: Assess the therapeutic potential of targeting the GOT2-PPARd axis in established PDAC. We will perform preclinical evaluation of GOT2/PPARd pathway inhibition together with therapeutic approaches aimed to increase antitumor T cell activity in diverse mouse models, validate our findings in patient specimens with known clinical outcomes and mutational status, and assess heterogeneity across the patient population with respect to the association between GOT2 signaling and T cell spatial regulation. Aim 2: Analyze the immune evasion mechanisms driven by cancer cell-intrinsic GOT2. We will apply in vitro co-culture systems, in vivo assays testing a suite of GOT2 mutants with varying fatty acid signaling capacity, and unbiased transcriptional analyses to understand the stepwise mechanisms mediating paracrine regulation of immune evasion. Aim 3: Interrogate fatty acid-mediated gene regulation by GOT2 and PPARd. We will analyze the genome-wide binding patterns of PPARd and additional immune-modulatory transcription factors putatively regulated by GOT2, and characterize chromatin states in the context of fatty acid signaling perturbations that prevent or permit antitumor immune responses. This work ...