Overexpression of the long noncoding RNA CCAT1 promotes metastasis via epithelial-to-mesenchymal transition in lung adenocarcinoma

The long noncoding RNA (lncRNA) colon cancer-associated transcript 1 (CCAT1) has been identified as an oncogene in multiple types of human malignancy, and the aberrant expression of CCAT1 has been associated with the tumorigenesis and progression of cancer. However, the underlying mechanism of how CCAT1 affects malignant behaviors in lung adenocarcinoma cells remains unknown. In the current study, the expression of CCAT1 was identified to be increased in lung adenocarcinoma tissues (n=96) by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and its expression level was associated with epidermal growth factor receptor (EGFR) expression (P=0.011), lymphatic metastasis (P=0.003) and tumor node metastasis (TNM) stage (P=0.003). In vitro, by using Transwell assays, the overexpression of CCAT1 was demonstrated to promote the migration and invasion of H358 lung adenocarcinoma cells; while downregulation of CCAT1 expression inhibited H1650 cell migration and invasion. Furthermore, western blot analysis indicated that aberrant CCAT1 expression may induce epithelial-to-mesenchymal transition (EMT) by regulating the expression levels of EMT markers (E-cadherin, N-cadherin and vimentin). In conclusion, these results indicate that CCAT1 is able to promote the metastasis of lung adenocarcinoma cells by inducing EMT.