miR-183-5p regulates ECM and EMT to promote non-small cell lung cancer progression by targeting LOXL4

BACKGROUND: Non-small cell lung cancer (NSCLC) progression is mediated by changes in gene expression induced by microRNAs. However, the underlying mechanisms remain to be elucidated. In this study, we investigated the roles of miR-183-5p and its target gene in lung cancer development. METHODS: Relative levels of miR-183-5p and lysyl oxidase-like 4 (LOXL4) expression in lung cancer cells or tissues were measured by quantitative reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence or Western blotting as appropriate. The binding of miR-183-5p to LOXL4 sequences was verified by a dual luciferase reporter assay, and cell proliferation was assessed by Cell Counting Kit-8 (CCK-8) and Edu staining. The cell cycle stage and apoptosis were detected by flow cytometry, and Transwell assays were performed to evaluate cell migration and invasion capabilities. The tumorigenic capability of cancer cells was analyzed using a cancer cell line-based xenograft nude mouse model. RESULTS: miR-183-5p expression was decreased in the lung cancer tissues and cell lines and was negatively correlated with elevated LOXL4 expression. Treatment with miR-183-5p mimics suppressed LOXL4 expression, while treatment with an miR-183-5p inhibitor promoted LOXL4 expression in A549 cells. miR-183-5p was found to directly bind to the 3’ UTR of the LOXL4 gene in A549 cells. Overexpression of LOXL4 enhanced cell proliferation, cell cycle progression, migration, and invasion, but repressed their apoptosis, and activated extracellular matrix (ECM) and the epithelial mesenchymal transition (EMT) process in A549 cells, while LOXL4 knockdown produced the opposite effects. Treatment with an miR-183-5P inhibitor promoted the proliferation, cell cycle progression, migration, and invasion of A549 cells but suppressed their apoptosis, and activated the ECM and EMT process, while all these effects were abrogated by LOXL4 knockdown. The tumorigenic capability of A540 cells in nude mice was greatly impaired by treatment with miR-183-5p mimics. CONCLUSIONS: miR-183-5p repressed the proliferation, migration, invasion, ECM formation, and EMT processes, and promoted the apoptosis of lung cancer cells by targeting LOXL4 expression.