Exploring the effects of extracellular vesicles secreted by cofilin-1 overexpressing cells on the migration and invasion ability of human lung cancer cells

Object: Type I actin-severing protein cofilin-1 (CFL-1) is a widely expressed regulator of the microfilament cytoskeleton in non-muscle cells. It plays a crucial role in actin cytoskeleton construction and influences cell motility. Overexpression of CFL-1 has been observed in various cancers and is related to tumor migration, invasion, and metastasis. In addition, studies have shown that the cytoskeleton plays a key role in exocytosis, implicating that CFL-1 may be a potential regulator of this process. Cancer cells secrete abundant extracellular vesicles (EVs) to mediate intercellular communication, and exosomes are one of the subtypes. Tumor-derived exosomes can promote tumor invasion and metastasis. Recent studies showed that CFL-1 is highly expressed in exosomes from advanced cancer, but its potential mechanisms in tumor-related exosomes remain unclear. Therefore, this study aims to explore the effects of CFL-1 on exosome secretion and whether CFL-1 influences lung cancer cells via exosome-mediated mechanisms. Methods: This study used H1299/tet-on-cofilin-1 (HCOXP) cells, a tetracycline-inducible cell line, which can induce cofilin-1 overexpression. First, conditioned medium was collected from HCOXP cells overexpressing cofilin-1, and exosomes were isolated by ultracentrifugation. Second, the purity of the isolated exosomes was verified by nanoparticle tracking analysis, transmission electron microscopy, and western blotting. To evaluate the impact on cell migration and invasion, exosomes derived from HCOXP cells were added to H1299, CL1-0, and BEAS2-B cells. Furthermore, the expression levels of matrix metalloproteinases (MMPs) in exosomes from HCOXP cells with and without cofilin-1 overexpression were compared. Results: The results showed that overexpression of CFL-1 stimulated cells to secrete more exosomes. It is also found that these exosomes may contain more contents. When these exosomes were applied to lung cancer and normal cells, exosomes derived from CFL-1 overexpressing HCOXP cells significantly accelerated the migration and invasion of H1299 cells. However, no increase in migration and invasion ability was observed in CL1-0 or BEAS-2B cells following treatment with these exosomes. In addition, elevated levels of matrix metalloproteinases (MMPs) were detected in exosomes from CFL-1-overexpressing HCOXP cells. Conclusion: Overexpression of CFL-1 in HCOXP cells was found to promote exosome secretion. These exosomes appear to exhibit homing specificity, potentially influencing their effects on target cells. Overall, this study found the critical role of CFL-1 in regulating the release and the potential impact of exosomes in the tumor microenvironment.