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 beta-catenin expression and subsequently up-regulates Snail in A549/CDDP cells. Taken together, these results revealed that AKT/beta-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. (C) 2013 Elsevier B.V. All rights reserved.