Zinc finger protein 668 suppresses non-small cell lung cancer invasion and migration by downregulating Snail and upregulating E-cadherin and zonula occludens-1

Zinc finger protein 668 (ZNF668) is a recently discovered protein and its expression levels, as well as its involvement in the invasion and metastasis of non-small cell lung cancer (NSCLC), are largely unknown. In the present study, immunohistochemical analysis demonstrated that ZNF668 protein expression was decreased in lung tumors (51/167, 30.5%) compared with adjacent normal lung tissues (43/62, 69.4%; P<0.001). Subsequent statistical analysis revealed that ZNF668 expression was negatively associated with increased tumor-node-metastasis stage (P=0.019) and lymph node metastasis (P=0.002). Following ZNF668 downregulation by transfection of a ZNF668-expressing plasmid or small interfering RNA, it was demonstrated that ZNF668 inhibited the invasion and migration of NSCLC cells. Furthermore, restoration of ZNF668 expression downregulated the expression of Snail and increased the protein levels of epithelial (E-) cadherin and zonula occludens-1 (ZO-1). The results of the present study suggest that ZNF668 is downregulated in human NSCLC. Furthermore, restoration of ZNF668 expression was demonstrated to decrease the expression of Snail and increase the expression of E-cadherin and ZO-1, suppressing the invasion and migration of NSCLC cells.