The Role of Extracellular Vesicles in the Progression of EGFR-Mutated Lung Cancer

Lung cancer remains a leading cause of cancer-related mortality worldwide, with non-small cell lung cancer accounting for approximately 85% of all cases. Despite advances in targeted therapies, lung cancer progression and metastasis continue to pose significant challenges. Recent research has highlighted the role of extracellular vesicles in mediating intercellular communication and influencing cancer progression. This thesis explores the involvement of EVs in lung cancer, particularly focusing on their role in tumor progression and metastasis, as well as their potential as biomarkers for early detection and therapeutic targets. Extracellular vesicles EVs, including exosomes and microvesicles, are membrane-bound particles released by all cell types. They carry proteins, lipids, and nucleic acids and by this facilitate intercellular communication and play a significant role in various physiological and pathological processes, including cancer. In lung cancer, EVs have been shown to contribute to tumor growth and metastasis by transferring oncogenic molecules and microRNAs (miRNAs) to recipient cells. This study aims to investigate the specific role of EVs in the progression of lung cancer with EGFR mutations. The study employed a multi-faceted approach to investigate the role of EVs in lung cancer. EVs were isolated from lung cancer cell lines and patient serum samples using differential ultracentrifugation and size-exclusion chromatography. Characterization of EVs was performed using nanoparticle tracking analysis NTA and Western blotting to confirm the presence of EV markers such as CD63, CD81, and TSG101. Functional assays, including cell proliferation, migration, and colony formation assays were conducted to assess the impact of EVs on recipient lung cancer cells. Additionally, quantitative reverse transcription PCR was used to analyze the miRNA content of serum-derived EVs from lung cancer patients, focusing on miRNAs implicated in cancer progression. The results demonstrated that EGFR-mutant lung cancer cells and EGF-treated cells release more EVs than EGFRwt lung cancer cells. Also, EVs derived from EGFR-mutant cells carry phosphorylated EGFR (p-EGFR) and promote cell proliferation, colony formation and migration in recipient EGFRwt cells. EVs isolated from patients’ serum were found to carry oncogenic miRNAs, such as Let-7a, miR-21, miR-155, miR-106b and miR-328, which are known to enhance tumor growth. Furthermore, serum-derived EVs from lung cancer patients exhibited higher levels of these oncogenic miRNAs compared to healthy controls, suggesting their potential as non-invasive biomarkers for lung cancer detection and monitoring. This thesis emphasizes the critical role of EVs in the progression of lung cancer. EVs facilitate tumor growth and dissemination by transferring oncogenic molecules and miRNAs to recipient cells, thereby altering their behavior and promoting a malignant phenotype. The findings highlight the potential of EVs as biomarkers for early detection and as therapeutic targets in lung cancer. By targeting the biogenesis, secretion, and uptake of EVs, novel therapeutic strategies could be developed to improve outcomes for lung cancer patients. Further research is needed to explore the mechanisms underlying EV-mediated communication and to translate these findings into clinical applications.