Resistance to targeted therapy and immunotherapy in Non-Small Cell Lung Cancer (NSCLC) and development of novel therapeutic approaches

Lung cancer is the first cause of cancer death worldwide and has been recently declared the most common tumor in the world. Non-small cell lung cancer (NSCLC) accounts for 85-90% of lung cancers and is characterized by poor prognosis and late diagnosis. The introduction of tyrosine kinase inhibitors (TKIs) targeting oncogenic mutations has redefined treatment options for oncogene-driven NSCLC. Immune checkpoint inhibitors (ICIs) have also provided a breakthrough in treating tumors with unknown or undruggable mutations. However, therapeutic resistance remains a major challenge, often driven by tumor heterogeneity and resistant subclonal populations that lead to disease progression despite initial responses. Additionally, some mutations currently lack effective therapies, leaving patients underserved by treatments. This PhD project aimed to investigate the mechanisms of resistance to these therapies, identify prognostic markers of therapy response and explore novel strategies for NSCLC treatment. To this end, we established a panel of primary cell cultures and patient-derived xenografts from tumors of patients whose disease progressed during TKI- or ICI-based therapies. Within this panel, we focused on specific cell models, each offering unique insights into NSCLC resistance. These models allowed us to explore the role of tumor heterogeneity in TKI resistance, characterizing the ROS1-rearranged ADK-VR2 and EGFR-mutated LIBM-ADK-11 cell lines. We also examined novel strategies for tumors with orphan mutations, using the BRAF class III-mutated ADK-14 and PDX-ADK-36 cell lines. Moreover, we examined mechanisms underlying resistance or adverse responses to ICIs, including hyperprogression, utilizing the KRAS-mutated ADK-17 and ADK-18 cell lines. For this purpose, we also employed a preclinical in vivo model of ICI resistance developed in syngeneic immunocompetent mice, using the transgenic murine BoLC.8M3 cell line, which carries a KRAS mutation and is p53 knock-down. Together, these models provide a comprehensive platform to understand resistance mechanisms in NSCLC and support the development of more effective therapies.