Abstract 382P
Background
Lung adenocarcinoma is one of the most prevalent malignancies with poor prognosis. Identifying genes associated with its development and prognosis is crucial for understanding the disease and developing targeted therapies.
Methods
We conducted genome-wide CRISPR/Cas9 screening in vitro and in vivo, intersecting results with prognosis-related genes in lung adenocarcinoma. DEFB1 expression was assessed using single-cell sequencing, immunohistochemistry, and public data. Functional studies were then performed in DEFB1 knockout and re-expressed cells, and co-immunoprecipitation experiments were utilized to explore DEFB1’s mechanism. Furthermore, the efficacy and safety of DEFB1 blocking antibodies was evaluated in vitro and in vivo.
Results
CRISPR/Cas9 screening revealed DEFB1 promotes lung adenocarcinoma proliferation while TCGA data showed a negative correlation between DEFB1 expression and patient survival. Single-cell sequencing indicated higher DEFB1 expression in cancer cells compared to other cells in microenvironment, while pseudotime analysis further suggested a strong association between DEFB1 and advanced tumor stages. In vitro and in vivo experiments demonstrated that DEFB1 enhances proliferation, migration, and invasion. Mechanistically, we found that DEFB1 interacts with Periplakin (PPL) to facilitate epithelial-to-mesenchymal transition (EMT) and proliferation. Additionally, DEFB1 interacts with Macrophage Migration Inhibitory Factor (MIF) to promote M2 polarization of macrophages. Furthermore, multiple anti-DEFB1 monoclonal antibodies were developed and one of them, mAb-5, potently blocked DEFB1’s function and inhibited lung adenocarcinoma progression in cell lines, organoids, xenografts, and spontaneous lung cancer models with a good safety profile.
Conclusions
DEFB1 is a novel driver in lung adenocarcinoma progression and the anti-DEFB1 monoclonal antibody mAb-5 shows promising therapeutic potential.
Legal entity responsible for the study
The authors
Funding
The National Natural Science Foundation of China (No. 82473184), the Shanghai Sailing Program (No. 24YF2704100), the National Natural Science Foundation of China (No. 82403100), and the Natural Science Foundation of Shanghai (No. 24ZR1409900).
Disclosure
All authors have declared no conflicts of interest.