Abstract: Objective To investigate the mechanism and expression of SOX2 and CTBP1 protein in the metastasis of non-small cell lung cancer( NSCLC). Methods Western blot was used to detect the expression of SOX2 and CTBP1 in fresh lung cancer tissues and corresponding paraneoplastic tissues. Immunoprecipitation was used to analyse the interaction between SOX2 and CTBP1 in the cells and tissues of non-small cell lung cancer. SOX2 and CTBP1 expression was assessed by immunohistochemistry in 114 paraffin-embedded sections. The regulatory mechanism of SOX2-CTBP1 interaction and its effect on metastasis of non-small cell lung cancer were assessed by plasmid transduction. Results The expression of SOX2 and CTBP1 were was significantly higher in NSCLC tissues than that of paired paraneoplastic tissues(P<0.05). CTBP1 could interact with SOX2 in NSCLC tissues and cells. The expression of SOX2 and CTBP1 were higher in tumor metastasis group compared with non-metastasis group(P<0.05). The high expression of CTBP1 protein is remarkably related with NSCLC clinical stage, histological differentiation, SOX2 expression and Ki-67 expression (P<0.05). At the cell level, interfering with CTBP1 expression can down regulate the expression of SOX2 and its downstream target gene Snail, so that the migration ability of H1299 cells is inhibited in vitro. Conclusions CTBP1 or SOX2 abnormal expression is potentially relevant to occurrence and development of NSCLC，and the interaction of them may promote the invasion and metastasis of NSCLC.

Key words: SOX2, CTBP1, non-small cell lung cancer, epithelial-mesenchymal transition, Lung cancer metastasis