Angiogenin elevates the invasive potential of squamous cell lung carcinoma cells through epithelial-mesenchymal transition

Abstract

Squamous cell carcinoma of the lung is one of the most aggressive cancers, and its aggressiveness is in part due to its intrinsic high rate of metastasis. Moreover, the process of epithelial-mesenchymal transition (EMT) appears to be involved in these neoplastic processes. Furthermore, EMT-type cells share many biological characteristics with the function of angiogenin (ANG) in squamous cell lung carcinoma. We conducted immunohistochemical analysis to detect the expression of ANG, E-cadherin, vimentin, N-cadherin, β-catenin and TGF-β1 in 60 cases of squamous cell lung carcinoma tissues. Western blot analysis was adopted to detect the protein expression levels of ANG and EMT markers. The effects of ANG on proliferation, migration and invasion of squamous cell lung carcinoma cells was analyzed by Cell Counting Kit-8, scratch assay and Transwell invasion chamber in order to reveal the role of ANG in the process of EMT in squamous cell lung carcinoma. The results revealed that ANG was aberrantly expressed in the squamous cell lung carcinoma specimens and was closely correlated with the differentiation of the cell lines. The expression of ANG was also significantly associated with metastasis and the stage of the squamous cell lung carcinoma cases. In addition, we validated that ANG influenced the expression of vimentin, E-cadherin, N-cadherin, β-catenin and TGF-β1 in SK-MES-1 cells. Most importantly, overexpression of ANG enhanced the migration and invasion of SK-MES-1 cells, while knockdown resulted in opposite effects. In the present study, we found that ANG plays an important role in EMT in squamous cell lung carcinoma and may be a valuable therapeutic target for squamous cell lung carcinoma.