Background: Increased IL-1β levels may promote carcinogenesis and metastasis by affecting tumor biology and the tumor microenvironment (TME). In this context, extracellular vesicles (EVs) play a key role in cell-to-cell communication, thus modulating the TME and immune response. Here, we aimed to test whether tumor-derived small EVs (TEVs) isolated from sensitive and osimertinib-resistant (OR) non-small-cell lung cancer (NSCLC) cells may promote EMT via fibronectin binding to α5β1 integrin as well as suppress the immune system and if these effects may be favored by IL-1β.
Methods: TEVs were isolated from control, OR, and IL-1β-stimulated NSCLC cells. Expressions of fibronectin and PD-L1 were screened in TEVs and the mRNA levels of vimentin and SMAD3 were also assessed in cancer cells after TEV co-culturing. Furthermore, to detect the effect on immune cells, we co-cultured TEVs with lung cancer patients' peripheral blood mononuclear cells (PBMCs).
Results: TEVs were positive for fibronectin and the highest protein levels were found in TEVs obtained from the OR and IL-1β-stimulated cells. TEV-mediated activation of α5β1 signaling led to the upregulation of vimentin and SMAD3 mRNA in NSCLC cells and stimulated cell migration. EVs also increased PD-1, CTLA-4, FOXP3, TNF-α, IL-12, and INF-γ mRNA in lung cancer patients' immune cells.
Conclusions: Our findings indicate that TEVs promote EMT in NSCLC cells by the activation of the fibronectin-α5β1 axis. Finally, IL-1β stimulation induces TEV release with biological properties similar to OR TEVs, thus leading to cancer invasion and immune suppression and suggesting that inflammation can promote tumor spreading.
Keywords: EMT; IL-1β; NSCLCs; cancer progression; immune suppression; tumor-derived small extracellular vesicles (TEVs).