ABSTRACT Lung cancer is the leading cause of cancer-related death worldwide. Lung adenocarcinoma (LUAD), the most common histological subtype, accounts for 40% of all cases. While genetically engineered mouse models (GEMMs) recapitulate the histological progression and transcriptional evolution of human LUAD, they are slow and technically demanding. In contrast, cell line transplant models are fast and flexible, but are often derived from clonal idiosyncratic tumors that fail to capture the full spectrum of clinical disease. Organoid technologies provide a means to create next-generation cancer models that integrate the most relevant features of autochthonous and transplant-based systems, yet robust and faithful LUAD organoid platforms are currently lacking. Here, we describe optimized conditions to continuously expand murine alveolar type 2 cells (AT2), a prominent cell-of-origin for LUAD, in organoid culture. These organoids display canonical features of AT2 cells, including marker gene expression, the presence of lamellar bodies, and an ability to differentiate into the AT1 lineage. We used this system to develop flexible and versatile immunocompetent organoid-based models of KRAS and ALK- mutant LUAD. Notably, the resultant tumors closely resemble their autochthonous murine counterparts and human LUAD. In contrast to comparable organoid platforms, our system supports long-term maintenance of the AT2 cellular identity, providing unprecedented ease and reliability to study AT2 and LUAD biology in vitro and in vivo .
