microRNA-204 shuttled by mesenchymal stem cell-derived exosomes inhibits the migration and invasion of non-small-cell lung cancer cells via the KLF7/AKT/HIF-1α axis

Non-small-cell lung cancer (NSCLC) remains the leading cause of cancer-related death worldwide. Accumulating researches have highlighted the ability of exosome-encapsulated microRNAs (miRNAs or miRs) as potential circulating biomarkers for lung cancer. The current study aimed to evaluate the significance of mesenchymal stem cells (MSCs)-derived exosomal miR-204 in the invasion, migration, and epithelial-mesenchymal transition (EMT) of NSCLC cells. Initially, the expression of miR-204 in human NSCLC tissues and cells was determined by RT-qPCR, which demonstrated that miR-204 was downregulated in NSCLC tissues and cells. Next, Krüppel-like factor 7 (KLF7) was predicted and validated to be a target of miR-204 using dual-luciferase reporter gene assay. NSCLC A549 cells were treated with MSCs-derived exosomes, after which the migration and invasion of A549 cells were detected and expression of EMT-related proteins (E-cadherin, N-cadherin, and Vimentin), KLF7, p-AKT/AKT, and HIF-1α were measured. The results of gain- and loss-of-function assays revealed that miR-204 overexpression in MSCs-derived exosomes inhibited KLF7 expression and the AKT/HIF-1α pathway activity, resulting in impaired cell migration, invasion, as well as EMT. In conclusion, the key findings of the current study demonstrate that exosomal miR-204 from MSCs possesses anticarcinogenic properties against NSCLC via the KLF7/AKT/HIF-1α axis.