LncRNA surfactant associated 1 activates large tumor suppressor kinase 1/Yes-associated protein pathway via modulating hypoxic exosome-delivered miR-4766-5p to inhibit lung adenocarcinoma metastasis

LncRNA surfactant associated 1 (SFTA1P) exhibits low expression in non-small cell lung cancer (NSCLC) tissues as compared with that in adjacent tissues, and may play a suppressing role in NSCLC. However, the effect and mechanism of SFTA1P on the metastasis of lung adenocarcinoma (LUAD) remain undefined, which are thus investigated in this research. Herein, potential impacts of SFTA1P on LUAD were determined through the Cancer Genome Atlas (TCGA) database and Gene Expression Profiling Interactive Analysis (GEPIA). After knockdown/ overexpression of SFTA1P, the metastatic ability of LUAD cells was evaluated by molecular biology experiments (cell counting kit-8 assay, scratch test, Transwell assay and Western blot). The effect of SFTA1P on Yes-associated protein (YAP) nuclear translocation was assessed by Western blot. Hypoxia-induced exosomes were extracted for LUAD metastasis analysis. The targeting relationship of SFTA1P/miR-4766-5p/large tumor suppressor kinase 1 (LATS1) was verified by dual-luciferase reporter assay and molecular biology experiments. Xenograft and lung metastasis models were constructed for in vivo validation. SFTA1P was lowly expressed in LUAD, which was associated with the poor prognosis of patients with LUAD. Up-regulated SFTA1P prevented the metastasis of LUAD cells and the nuclear translocation of YAP. Hypoxia-induced exosomes stimulated LUAD cell metastasis, but inhibited the SFTA1P and LATS1/YAP axes. MiR-4766-5p acted as an intermediate "bridge" for SFTA1P to regulate LATS1. SFTA1P repressed xenograft growth and LUAD cell metastasis. To sum up, SFTA1P activates hypoxic exosome-delivered miR-4766-5p through modulating LATS1/YAP pathway, thereby suppressing LUAD cell metastasis, which may serve as a suitable target for the LUAD therapy.