Upregulation of SOX9 promotes cell proliferation, migration and invasion in lung adenocarcinoma

Sex determining region Y-box 9 (SOX9) is an important transcription factor in development and has been implicated in several types of cancer. Although the association between upregulation of SOX9 and lung adenocarcinoma (ADC) has been reported previously, the role of SOX9 in the proliferation, migration and invasion of cancer cells remains unclear. Therefore, in the present study, SOX9 expression was detected in 163 human lung adenocarcinoma tissues by immunohistochemistry and western blotting. It was found that the SOX9 protein was over-expressed in the majority of lung adenocarcinoma. The full-length human SOX9 plasmid was then transfected into the lung ADC A549 cell line. An MTT assay was used to investigate the role of SOX9 in cell proliferation. Scratch and extracellular matrix cell invasion assays were performed to investigate whether SOX9 promotes the migration and invasion of lung ADC cells. The results revealed that ectopic overexpression of SOX9 in the lung adenocarcinoma cell line resulted in a marked increase in cell proliferation, migration and invasion. Accordingly, knockdown of SOX9 by RNA interference resulted in the inhibition of cell growth, migration and invasion. The present data indicate that SOX9 may act as a novel marker for lung adenocarcinoma and perform an important role in cell proliferation, migration and invasion.