PROJECT SUMMARY Computerized chest tomography (CT) lung cancer screening programs have increased the detection of premalignant non-solid (NS) nodules that harbor preinvasive or minimally invasive adenocarcinoma. Given that NS nodules can progress to invasive adenocarcinoma (solid nodules), intercepting progression is considered an urgent clinical priority. However, the cellular and molecular alterations that accompany disease progression are poorly understood. NS nodules exhibit lower rates of HLA deletions than invasive/metastatic lung cancer, and our integrated clinical and preclinical investigations have recently uncovered T cell-enriched immune microenvironments, including elevated activated T regs in NS nodules. Global genomic analysis of NS nodules identified high tumor-associated antigen (TAA) XAGE-1b and several HLA-restricted neoantigens. These findings have led to the hypothesis that RNA-based vaccination against NS nodule-associated antigens and or neoantigens can drive activation of T helper and cytotoxic CD8+ T cells while reducing tumor-infiltrating Tregs to impair NS nodule progression to invasive adenocarcinoma. We will test this hypothesis through two Specific Aims. Aim 1 will determine the potential of lipo-nanoparticle RNA (LNP RNA) XAGE-1b vaccination in intercepting NS nodule progression in preclinical syngeneic models of NSCLC. A state-of-the-art LNP-XAGE-1b RNA vaccine will be manufactured and optimized in collaboration with the LNP-RNA shared resource facility. A novel physiologically relevant mouse model recapitulating the progression of human NS nodules will be used to determine the efficacy of the XAGE-1b vaccine in intercepting the progression of NSN to invasive carcinoma. Mechanisms associated with LNP RNA vaccine immune interception will be elucidated with comprehensive immune profiling approaches. Aim 2 will delineate the most immunogenic and cytotoxic patient lung NS nodule antigens and neoantigens identified in a multi-ethnic cohort of clinically annotated NS nodules for vaccine payloads. Human class I MHC (HLA) transgenic mice will identify the most immunogenic lung NSN vaccine cargo in vivo. Patient-specific tumoroid/autologous T-cell cocultures and immunopeptidomics will be used to confirm immunogenicity and antigenic presentation on autologous patient HLA. Finally, the cytotoxic potential of NS nodule patient neoantigen-specific T-cells against autologous tumoroids will be used to rank neoantigens. We expect to delineate the most immunogenic vaccine cargo together with informative correlative studies for NCI PREVENT pre-IND vaccine development and NCI CP-NET LS immunoprevention clinical trials and provide critical mechanistic insights into effective patient LNP RNA immune interception vaccines.