Stomatin-like protein 2 regulates survivin expression in non-small cell lung cancer cells through β-catenin signaling pathway.

The overexpression of stomatin-like protein-2 (SLP-2) is commonly observed in non-small cell lung cancer (NSCLC) cells. In the present study, we transfected a number of NSCLC cells with an SLP-2 shRNA-expressing vector (AdSLP2i) and examined its possible effects on cell growth and apoptosis. We found that suppression of SLP-2 expression inhibited cell growth, and that the apoptosis induced by SLP-2 suppression was correlated with decreased survivin protein expression. Moreover, the reduced survivin expression was found to be associated with reduced β-catenin nuclear localization and appeared not to be modulated through the AKT signaling pathway. By using immunoprecipitation and proteomics to analyze protein-protein interactions in A549 cells with SLP-2 overexpression, we found that annexin A2 interacted with SLP-2 and β-catenin directly. Our data further suggested that the knockdown of SLP-2 gene affected the SLP-2/Annexin A2/β-catenin cascade formation, reduced the translocation of cytoplasmic β-catenin into nucleus, and downregulated downstream target genes. The results presented in this study, together with our previous findings, suggest that SLP-2 promotes NSCLC cell proliferation by enhancing survivin expression mediated via β-catenin pathway.