Effect Of Morphine On The Malignant Biological Behavior Of Non-small Cell Lung Cancer Cells And Exploration Of Its Mechanism

Background:Lung cancer is the first leading cause of cancer-related mortality.Morphine is a commonly used clinical drug for both surgical resection and pain treatment in patients with advanced lung cancer.Morphine,aμ-opioid receptor（MOR）agonist,has been shown to be related to the activity of cancer cells,and a higher morphine dosage reduces the survival time of patients with lung cancer.Further research on the function of MOR showed upregulated MOR expression in the tumor tissues from patients with prostate cancer and that high MOR expression was positively correlated with the metastasis of prostate cancer.Similar results were obtained from studies of esophageal and laryngeal squamous cell carcinoma.The MOR specific antagonist methylnaltrexone（MNTX）reduces the viability of lung cancer cells by inhibiting Src activation.However,the effect of morphine on the malignant behavior of lung cancer cells remains unclear.The aim of this study was to investigate the specific molecular mechanism by which morphine regulates the malignant biological behavior of non-small cell lung cancer.Methods:In this study,immunofluorescence staining and Western blot analyses were performed to detect MOR expression in BEAS-2B cells and H460 cells.The effects of morphine and Src/PI3K/AKT/mTOR pathway inhibitors on the proliferation of H460cells were detected by Cell Counting Kit-8,detecting the migration and invasion of H460cells by wound-healing assay and Transwell assays respectively.Western blot analysis was used to attest Src/PI3K/AKT/mTOR pathway activity and the expression of apoptosis-related proteins.Flow cytometry was used to detect cell cycle and apoptosis.Each nude mouse was subcutaneously injected with H460 cells,and morphine was subcutaneously injected into the tumor-forming mice.Western blotting analysis was used to detect the activity of Src/PI3K/AKT/mTOR pathway and the expression of apoptosis-related proteins in tumor tissue.Results:Compared with normal lung epithelial cells,the expression of MOR in non-small cell lung cancer cells was significantly increased.Low concentration of morphine could promote the proliferation of H460 cells,while high concentration of morphine could inhibit it.Morphine can significantly promote the migration and invasion of H460cells,affect the process of cell cycle by inhibiting the transition of S/G₂ phase,and have anti-apoptotic effect on H460 cells.In addition,morphine increases the phosphorylation of Src,which in turn activates the target of PI3K/AKT/mTOR pathway.MOR antagonist MNTX and Src inhibitor PP1 could inhibit morphine-induced proliferation,migration,invasion and phosphorylation of Src/PI3K/AKT/mTOR pathway.MNTX,PP1 and PI3K/AKT inhibitor Degulin reversed the anti-apoptotic effect of morphine on lung cancer cells.Subcutaneous injection of morphine can promote tumor growth in nude mice,significantly up-regulate the activity of Src/PI3K/AKT/mTOR pathway in tumor tissue,and inhibit the expression of apoptosis-related proteins.Conclusion:Morphine promotes the malignant biological behavior of H460 cells by activating the MOR and Src/mTOR signaling pathways.