Abstract 1434: Modeling the 3q26 OncCassette using genetically engineered mice

Abstract

Abstract Lung squamous cell carcinoma (LUSC) is a devastating disease, accounting for ~30% of all lung cancer diagnoses and ~40,000 deaths annually in the United States alone. LUSC patients suffer from high prevalence of relapse and a dismal 5-year survival of only ~24%. The lack of animal models that reflect the salient features of human disease to assess the safety and efficacy of drugs, and to explore the underlying molecular mechanisms of LUSC tumor biology, is a major impediment for LUSC patients. We have identified concomitant 3q26 copy number gain (CNG) and TP53 loss as a defining genetic alteration present in ~90% of LUSC tumors. Furthermore, we have identified and characterized three 3q26 oncogenes (PRKCI, ECT2 and SOX2) that genetically and biochemically collaborate to drive LUSC tumor formation. Using syngeneic mouse modeling, we have demonstrated that coordinate overexpression of Prkci, Ect2 and Sox2, and loss of Trp53 in ex vivo cultures of lung basal stem cells (LBSCs; a cell of origin for LUSC) drives transformation of these cells into tumors of exclusively LUSC histopathology. These findings lead to the hypothesis that PRKCI, ECT2 and SOX2 represent a multigenic driver of 3q26 CNG-driven LUSC, which we term the 3q26 OncCassette. Based in these findings, we have developed and begun characterizing the first autochthonous genetically engineered mouse model (GEMM) to study 3q26 OncCassette-driven tumorigenesis. Our novel immune competent GEMM will provide critical insight into tumor initiation and progression of preneoplastic lesions to malignant LUSC and allow characterization of the immune landscape in these tumors. Citation Format: Kayleah M. Meneses, Yi Liu, Capella R. Weems, Lee Jamieson, Duy T. Nguyen, Verline Justilien, Nicole R. Murray, Alan P. Fields. Modeling the 3q26 OncCassette using genetically engineered mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1434.