Hypoxic Non-Small-Cell Lung Cancer Cell-Secreted Exosomal microRNA-582-3p Drives Cancer Cell Malignant Phenotypes by Targeting Secreted Frizzled-Related Protein 1

BACKGROUND: Hypoxic environment and exosomes (exos)-mediated intercellular communication are crucial for cancer invasion and metastasis, but the mechanisms are not yet fully understood. In this study, we investigated the regulatory effect of hypoxic tumor cell-secreted exosomal miR-582-3p on non-small-cell lung cancer (NSCLC) cell malignant phenotypes. METHODS: The concentration and diameters of exos were evaluated by nanosight particle tracking analysis. microRNA-582-3p (miR-582-3p) expression was detected by quantitative real-time PCR. The fluorescent dye PKH26 was used to label exos. The direct interaction between miR-582-3p and secreted frizzled-related protein 1 (SFRP1) was determined by dual-luciferase activity assay. NSCLC cell proliferation, migration, and invasion abilities were assessed by cell count kit-8 assay, wound healing assay, and transwell migration and invasion assay. Western blot analysis was performed to detect the protein expression level. RESULTS: Hypoxic NSCLC cell-derived exos promoted the proliferation, migration, and invasion of normoxic NSCLC cells. miR-582-3p expression was upregulated in hypoxic NSCLC cells and hypoxic NSCLC cell-secreted exos. Hypoxic NSCLC cell-derived exos transmitted miR-582-3p to normoxic NSCLC cells. Hypoxic NSCLC cell-secreted exosomal miR-582-3p promoted the proliferation, migration, and invasion of normoxic NSCLC cells. miR-582-3p inhibited the expression of SFRP1 protein by binding to its 3ʹ-UTR. In addition, enforced expression of SFRP1 restrained malignant phenotypes of normoxic NSCLC cells, which was abrogated by hypoxic NSCLC cell-secreted exosomal miR-582-3p. CONCLUSION: Hypoxic NSCLC cell-secreted exosomal miR-582-3p drives cancer cell malignant phenotypes by targeting SFRP1, which provides a better understanding of cancer metastasis and may facilitate the development of therapeutics against human NSCLC.