Acquisition of epithelial–mesenchymal transition phenotype and cancer stem cell-like properties in cisplatin-resistant lung cancer cells through AKT/β-catenin/Snail signaling pathway

Cisplatin is a first-line chemotherapeutic agent in the treatment of non-small cell lung cancer (NSCLC), but the therapeutic effect is disappointing, partly due to drug resistance. Emerging evidence showed that chemoresistance associates with acquisition of epithelial–mesenchymal transition (EMT) phenotype and cancer stem cell-like properties. However, the underlying mechanism is not entirely clear. In this study, we showed that cisplatin-resistant A549 cells (A549/CDDP) acquire EMT phenotype associated with migratory and invasive capability. A549/CDDP cells also displayed enhanced cancer stem cell-like properties. Increased expression of transcription factor Snail, but not ZEB1, Slug and Twist, was observed in A549/CDDP cells. Knockdown of Snail reversed EMT and significantly attenuated migration, invasion and cancer stem cell-like properties of A549/CDDP cells. Conversely, overexpressed Snail in A549 cells induced EMT and cancer stem cell-like properties. Finally, we demonstrated that activated AKT signal leads to increased β-catenin expression and subsequently up-regulates Snail in A549/CDDP cells. Taken together, these results revealed that AKT/β-catenin/Snail signaling pathway is mechanistically associated with cancer stem cell-like properties and EMT features of A549/CDDP cells, and thus, this pathway could be a novel target for the treatment of NSCLC.