Non-thermal Plasma-Derived Reactive Oxygen Species Induces Cell Death in Radioresistant Head and Neck Cancer <i>via</i> the c-MET/STAT3 Pathway

Here, we found that radioresistant (RR) cancer cells exhibited reduced ROS levels and activation of the mesenchymal-epithelial transition factor/signal transducer and activator of transcription 3 (c-MET/STAT3) pathway. To target common vulnerabilities in RR cancers, we applied ROS enhancement therapy using nonthermal plasma-activated media (NTPAM), a novel approach that effectively inhibits the viability of RR cancer cells and is associated with inactivation of the c-MET/STAT3 pathway. Mechanistically, the downregulation of total c-MET is related to ROS-mediated lysosomal degradation. In addition, NTPAM suppressed tumor growth in a mouse model of RR cancer, concurrently reducing the levels of both the total and activated forms of c-MET and decreasing STAT3 phosphorylation.Innovations and Conclusions:These findings suggest that ROS enhancement therapy can overcome radiation resistance, thereby offering a compelling rationale for considering NTPAM as a stand-alone or complementary therapeutic approach for treating patients with HNSCCs. <i>Antioxid. Redox Signal.</i> 44, 182-196.