Foxk2 inhibits non-small cell lung cancer epithelial-mesenchymal transition and proliferation through the repression of different key target genes.

Increasing evidence suggests that numerous fork-head transcription factors are required to repress the mammalian cells phenotype. Among them, Foxk2 is a ubiquitously expressed family member, but the role of Foxk2 in mediating tumor metastasis in non-small cell lung cancer has not been explored. In this investigation reduced Foxk2 expression was found in lung adenocarcinoma tissues compared with the adjacent non-tumor tissues, and was associated with better overall survival. Low expression was also found in the NSCLC cell lines such as A549, NCI-H520, H1299, H358 and H460 cells. Recombinant lentivirus expressing Foxk2 constructs or ShFoxk2 were developed and transfected into A549 cells or NCI-H520 cells, immunofluorescence assay, qRT-PCR, and western blot analysis were used to measure the change of the epithelial markers, E-cadherin and α-catenin, and mesenchymal markers N-cadherin and vimentin. Wound healing assay and Transwell assay were used to measure the relative cell invasion ability. MTT assay, Edu assay, and cell cycle distribution analysis were used to confirm the effect of Foxk2 on cell proliferation. ChIP-seq, qChIP, as well as luciferase reporter gene assays were used to detect the target genes regulated by Foxk2, Bioinformatics predicated the potential miRNAs that could target Foxk2. Our study demonstrated that Foxk2 played major roles in NSCLC EMT by directly targeting N-cadherin and Snail, we found that Foxk2 regulated NSCLC cell growth by suppressing the expression of cyclin D1 and CDK4, which suggested that Foxk2 might be a multifunctional regulator in NSCLC. The expression of Foxk2 may be regulated by miR-1271, which could serve as a promising therapeutic target for NSCLC.