MTA1 gene silencing inhibits invasion and alters the microRNA expression profile of human lung cancer cells.

Metastasis-associated gene 1 (MTA1) is involved in the carcinogenesis and metastasis of many human carcinomas. However, its exact role in non-small cell lung cancer (NSCLC) is still unclear. Using immunohistochemistry analysis, we recently identified MTA1 to be associated with the progression of NSCLC. Here, we carried out further analysis on the effect of MTA1 knockdown in an NSCLC cell line on cell functions and the global microRNA (miRNA) expression profile. We succeeded in establishing the MTA1 knockdown NSCLC cell line using RNA interference (RNAi), and found that the silencing of MTA1 resulted in the effective inhibition of the invasive ability of NSCLC cells, but not of the cell growth in vitro. We performed an miRNA microarray analysis and demonstrated for the first time that MTA1 knockdown significantly changed the expression of some miRNAs in NSCLC cells. Among them, some have a well-characterized association with cancer progression, e.g. miR-125b, miR-210, miR-103, miR-194 and miR-500. In summary, it is evident from our results that MTA1 functions in regulating the invasive phenotype of lung cancer cells and this regulation may be through altered miRNA expression. The interaction between MTA1 and the miRNAs which contributes to lung cancer is worthy of further investigation.