B111-05 Targeting P2ry2 Reprograms Tumor Immunity and Inhibits Tumor Growth in Kras- and Egfr-mutant Non-small Cell Lung Cancer

Rationale The enrichment of immunosuppressive M2 macrophages, combined with diminished CD8+ T cell infiltration, represents a key mechanism driving tumor progression and limiting immunotherapy efficacy in non-small cell lung cancer (NSCLC). KRAS and EGFR mutations are the most common mutations in the early and late stages of NSCLC, respectively. Methods We determined purinergic P2Y2 receptor (P2RY2) expression in a cohort of NSCLC adenocarcinoma patients using RNAscope and multicolor immunofluorescence. Furthermore, we evaluated the in vivo function using a syngeneic murine transplantation model with Kras/Nras-mutant LLC1 cells, which closely replicate the characteristics of clinical adenocarcinoma in smokers. Additionally, we employed agenetically engineered model that expresses the most prevalent EGFR-activating mutation (L858R) conditionally and lacks p53 in the lungs. Results P2RY2 expression is significantly elevated in human NSCLC compared to non-malignant tissues and M2-like macrophages expressing P2RY2 correlate strongly with TNM staging. Selective pharmacological inhibition of P2RY2 in syngeneic transplantation or autochthonous mouse models of NSCLC driven by Kras or Egfr mutations resulted in a significant reduction of M2-like macrophages, enhanced CD8+ T cell migration and tumor infiltration, and a marked decrease in tumor burden. Similar results were evident following the genetic deletion of P2RY2, validating the impact on the tumor microenvironment. Conclusions Our study underscores the clinical significance of P2RY2 in NSCLC and provides evidence of its pivotal role in the regulation of M2 macrophage enrichment and the exclusion of CD8+ T cells from the tumor microenvironment (TME). Our in vivo models provide a clinically relevant platform for immunotherapeutic investigation. Targeting P2RY2, either alone or in combination with immune checkpoint blockade, may offer a novel immunotherapeutic intervention for NSCLC. This abstract is funded by: Austrian Science Fund, City of Vienna Fund for Innovative Interdisciplinary Cancer Research, Fellinger Krebsforschung, Hungarian National Research