Epithelial Splicing Regulatory Protein 1 Inhibits the Invasion and Metastasis of Lung Adenocarcinoma.

ABSTRACT

Despite the development of various treatments, metastasis remains a significant problem with lung adenocarcinoma (ADC). The role and mechanism of epithelial splicing regulatory protein 1 (ESRP1), an epithelial-specific RNA binding protein, on promoting the invasion and metastasis of lung ADC remain to be fully elucidated. Immunohistochemical analysis in 125 human lung ADC tissue samples demonstrated that ESRP1 overexpression was inversely related to the presence of metastases, tumor size, and clinical stage of lung ADC. Impaired ESRP1 expression was also found to stimulate the invasion capacity of lung ADC cells both in vitro and in vivo. Functionally, overexpression of the ZEB1 gene decreased ESRP1 expression, and knockdown of the ZEB1 gene caused increased ESRP1 expression. On the basis of a gene array analysis, the expression of ESRP1 was associated with the regulation of the extracellular matrix. The expression of CD44 and fibroblast growth factor receptor, representatives that interact with the extracellular matrix, was studied. The CD44 subtypes promoted lung ADC cell invasion by regulating matrix metalloproteinase 2 expression. In conclusion, ESRP1 inhibits the invasion and metastasis of lung ADC and plays a role in regulating proteins involved in epithelial-to-mesenchymal transition.