Nano-icilin-driven TRPM8 activation elicits immunogenic exosomes with antitumor effects.

[BACKGROUND] Transient receptor potential melastatin 8 (TRPM8) is a cold-sensing cation channel that regulates calcium (Ca2+) levels in cells. Its overexpression is linked to tumor development and progression. TRPM8 activation by specific agonists leads to increased Ca2+ influx, causing stress and apoptosis. This stress can enhance the production and release of exosomes, which have antitumor immunity properties. We hypothesize that activating TRPM8 with nano-icilin can stimulate immune responses when administered peritumorally.

[METHOD] 4T1 cancer cells were treated with icilin nanoparticles and hypothermia to evaluate cytotoxicity, apoptosis, calcium flux, and exosome extraction. Isolated exosomes were characterized and tested in vivo for antitumor immune response in a mouse model. Tumor growth, cytokines (IL-2, IL-12, IL-10, and IL-1β), and immunohistochemistry (IHC) were assessed. Data were analyzed using ANOVA and Duncan's test (P ≤ 0.05).

[RESULTS] TRPM8 activation by icilin nanoparticles triggers apoptosis and calcium influx in 4T1 cells. Exosomes from treated cells exhibited altered size, charge, and increased levels of DAMPs (HMGB1, HSP70). Administering these exosomes significantly inhibited tumor growth, increased CD4+/CD8+ T cells, and elevated IL-2 and IL-12, while reducing IL-10 and PD-L1, thus preventing lung metastasis.

[CONCLUSIONS] Activation of TRPM8 by icilin or cold can induce immunogenic exosomes, enhancing T cell infiltration, proinflammatory cytokines, and tumor suppression, offering a new strategy to boost immune responses against cancer.