Extracellular vesicles enhance the targeted delivery of immunogenic oncolytic adenovirus and paclitaxel in immunocompetent mice.

Extracellular vesicles (EVs), are naturally occurring cargo delivery tools with the potential to be used as drug vehicles of single agents or combination therapies. We previously demonstrated that human lung cancer cell-derived EVs could be used for the systemic delivery of oncolytic virus (OVs) and chemotherapy drugs such as paclitaxel (PTX), leading to enhanced anti-tumor effects in nude mice. In the current work, we evaluated the biodistribution of EVs by using bioluminescence and fluorescence imaging technologies, thus proving the ability of these EVs-formulations to specifically target the neoplasia, while leaving other body tissues unaffected. Moreover, in vivo imaging of NFκB activation in an immunocompetent reporter mouse model allowed to demonstrate the selective ability of EVs to induce tumor-associated inflammatory reactions, which are characterized by immunogenic cell death and CD3+/CD4+/CD8+ T-cell infiltration. While EVs have the potential to induce a systemic immune reaction by pro-inflammatory cytokines, our study provides compelling evidences of a localized inflammatory effect in the peritumoral area. Collectively, our findings strongly support the systemic administration of EVs formulations with OVs alone or in combination with chemotherapy agents as a novel strategy aimed at treating primary and metastatic cancers.