Abstract: Background and purpose: The application of tyrosine kinase inhibitor (TKI) in lung cancer patients with epidermal growth factor receptor (EGFR) mutations has been a significant breakthrough recently. However, almost 70% patients would suffer from TKI drug resistance inevitably so that the treatment effect is unsatisfactory. In order to look for new molecular target for improving the level of clinical diagnosis and treatment of lung cancer, this study aimed to investigate the regulatory effects of Lyn kinase on cell line with EGFR mutation and the influence of Lyn kinase on EGFR downstream signaling pathway. Methods: The lentiviral vector expressing Lyn was used to construct the Lyn kinase high expression Hcc827 cell lines (Hcc827-Lyn^+/+). By means of tumor bearing experiment in nude mice, MTT experiment, cloning experiment, invasion experiment and Western blot method, we detected the ability of proliferation, cloning and invasion of high Lyn kinase expression Hcc827 cell lines and expression level of EGFR signaling pathway related proteins. Results: Compared with Hcc827 cell lines, Hcc827- Lyn^+/+ cell lines showed stronger ability of proliferation in nude mice tumor bearing experiment. However, there was no distant metastasis in any nude mouse. Results of in vitro culture showed Hcc827-Lyn^+/+ cell lines had stronger ability of proliferation, cloning and invasion compared with Hcc827 cell lines. The related proteins of EGFR and its downstream signaling pathway were upregulated in Hcc827-Lyn^+/+ cell lines. Conclusion: High expression of Lyn kinase can promote the proliferation, cloning and invasion ability of Hcc827 cell lines. These effects are achieved by EGFR signaling pathway upregulation.

Key words: Lyn kinase, Lung adenocarcinoma, Epidermal growth factor receptor, Nude mice, Proliferation, Invasion