Prolonging the anti-tumor effects of cold atmospheric plasma via exosome-mediated signaling.

Cold atmospheric plasma (CAP) has emerged as a promising non-thermal modality in cancer research due to its ability to induce selective cytotoxicity through reactive oxygen and nitrogen species. However, the limited penetration depth and instability of plasma-derived reactive species in complex biological environments remain major obstacles to its therapeutic application. In this study, we investigated whether exosomes derived from CAP-treated cancer cells (CAP-Exo) could serve as functional mediators to extend and amplify the anti-tumor effects of CAP. Using chronic myeloid leukemia K562 cells as a primary model, we demonstrate that CAP treatment induces pronounced oxidative stress, apoptosis, and sustained proliferative suppression. Importantly, exosomes isolated from CAP-treated cells exhibited enhanced anti-proliferative and pro-apoptotic activity in recipient cells compared to exosomes from untreated controls. To assess the broader applicability of this strategy, we further evaluated the effects of CAP and CAP-Exo in multiple solid tumor models, including breast, renal, and hepatocellular carcinoma cells, both in vitro and in vivo. CAP exposure consistently reduced cell viability across solid tumor cell lines, while CAP-Exo retained potent cytotoxic activity against breast cancer cells and significantly suppressed tumor growth in corresponding xenograft models without inducing systemic toxicity. Mechanistically, CAP-induced stress reprogrammed exosomal cargo, enabling the transfer of death-associated molecular signals to recipient tumor cells and thereby promoting apoptosis. Collectively, our findings indicate that CAP-modified exosomes represent a biologically active, cell-free approach that extends the anti-tumor effects of CAP treatment across both hematological malignancies and solid tumors. Rather than replacing existing therapeutic modalities, CAP-Exo may serve as a complementary strategy to enhance CAP-based cancer interventions and overcome current limitations associated with direct CAP application.