Effect Of Down-regulated CEP55 Expression On The Development Of Non-small Cell Lung Cancer

Objective: The effects of down-regulated CEP55 expression on proliferation,migration and invasion of non-small cell lung cancer（NSCLC）cells were observed in vitro.The effect of inhibition of CEP55 expression on tumor growth in tumor-bearing mice was observed in vivo.In order to add new content for lung cancer research,and provide new ideas and strategies for clinical treatment of lung cancer.Methods: The expression of CEP55 in lung cancer and normal tissues and the correlation between the expression of CEP55 and the overall survival（OS）of lung cancer patients were analyzed by bioinformatics.In vitro experiments: normal lung epithelial cells（BEAS-2B cells）and NSCLC cells（A549,H1299 and H1975 cells）were cultured conventionally,and the CEP55 protein in cells was detected by Western blot,and the A549 cells with the highest CEP55 protein expression were selected as subsequent experimental cells.A549 cells were randomly divided into control group（transfected with Lipofectamine2000 only）,si-NC group（transfected with Lipofectamine2000 and NC sequence）and si-CEP55 group（transfected with lipofectamine 2000 and si-CEP55 sequence）.Colony formation assay and MTT assay were used to detect cell proliferation.Scratching assay and Transwell assay were used to detect cell migration and invasion,and Western blot was used to detect intracellular CEP55,EMT-related proteins and PI3K/AKT/m TOR signaling pathway related proteins.In vivo experiment: sh-CEP55 stable strain A549 was constructed by lentivirus transfection.Twelve Balb/C nude mice were randomly divided into control group and sh-CEP55 group to construct lung cancer mouse models.At 30 days after modeling,the mice were sacrificed and the tumor volume and weight were weighed.Cell morphology was observed by HE staining,and the expression of ki-67 was detected by immunohistochemistry.Results: Compared with normal tissues,CEP55 was highly expressed in lung cancer（P<0.05）;In lung adenocarcinoma,patients with low CEP55 expression had longer OS than those with high CEP55 expression（P<0.01）.In vitro experiment: compared with si-NC group and control group,the relative expression of CEP55 protein in si-CEP55 group was lower.The number of cell colonies was lower.The number of migrating cells and invading cells was lower.The proliferation ability of cells（OD value）was lower at24,48 and 72 h,and the protein expressions of p-Akt and p-m TOR were lower.Ecadherin protein expression was high.N-cadherin and Vimentin protein expression was low（all P<0.05）.In vivo: compared with the control group,the sh-CEP55 group significantly inhibited tumor proliferation（P<0.05）.Conclusion: The silencing of CEP55 gene can inhibit the proliferation,migration and invasion of NSCLC cells,and its mechanism may be related to the inhibition of the activation of PI3K/AKT/m TOR signaling pathway and thus affect EMT.CEP55 may be a potential target for the treatment of lung cancer.