Downregulation of Meg3 enhances cisplatin resistance of lung cancer cells through activation of the WNT/β-catenin signaling pathway

Abstract

Maternally expressed gene 3 (Meg3) has been shown to promote tumor progression. However, the role of Meg3 in the development of a chemoresistant phenotype of human lung cancer has remains. Reverse transcription-quantitative polymerase chain reaction analysis was used to determine the expression of Meg3. Flow cytometric analysis and MTT assay were also used to investigate the cell cycle and apoptosis. The present study detected that the expression levels of Meg3 were significantly lower in cisplatin-resistant A549/DDP lung cancer cells, compared with those in parental A549 cells. Furthermore, upregulation of Meg3 was able to re-sensitize the A549/DDP cells to cisplatin in vitro. Whereas downregulation of Meg3, by RNA interference, decreased the sensitivity of A549 cells to cisplatin. The results of the present study also demonstrated that the Meg3-mediated chemosen-sitivity enhancement was associated with the induction of cell-cycle arrest and increased apoptosis, through regulation of p53, β-catenin and survivin, which is a target gene of the WNT/β-catenin signaling pathway. In conclusion, these results suggested that Meg3 may have a crucial role in the development of cisplatin resistance in non-small cell lung cancer.