Background/Aim: Plasma-activated medium (PAM), which generates reactive oxygen and nitrogen species (RONS), has emerged as a promising anti-cancer approach. However, although PAM effectively eliminates bulk tumor cells, surviving populations often acquire enhanced stem cell-like properties, suggesting selective resistance in cancer stem cells (CSCs). This study aimed to elucidate the molecular mechanisms underlying CSC resistance to PAM-induced oxidative stress in non-small cell lung cancer (NSCLC). Materials and Methods: CD133+ and CD133− subpopulations were isolated from A549 lung cancer cells to evaluate their sensitivity to PAM-induced cytotoxicity. Intracellular reactive oxygen species (ROS) levels, apoptosis, and antioxidant defense mechanisms were assessed in vitro, while therapeutic efficacy was examined using xenograft mouse models. Results: CD133+ A549 cells exhibited marked resistance to PAM-induced apoptosis compared with CD133− cells, accompanied by significantly reduced intracellular ROS accumulation. Peroxiredoxin 5 (PRDX5) was identified as a key antioxidant enzyme that was highly up-regulated in CD133+ cells and essential for maintaining redox homeostasis. Genetic silencing of PRDX5 in CD133+ cells significantly enhanced PAM-mediated cytotoxicity both in vitro and in vivo, restoring sensitivity to oxidative damage. Furthermore, combining PRDX5 knockdown with PAM treatment or co-administering PAM with paclitaxel substantially suppresses tumor growth in xenograft models, reducing tumor burden and inflammatory responses. These findings reveal PRDX5 as a key survival factor enabling CSCs to evade plasma therapy and suggest that targeting PRDX5 alongside PAM or conventional chemotherapy could improve treatment outcomes in NSCLC. Conclusion: PRDX5 plays a central role in mediating oxidative stress resistance in CD133+ lung cancer stem-like cells, enabling their survival following PAM treatment. Targeting PRDX5, either alone or in combination with PAM or conventional chemotherapy, represents a promising strategy to overcome cancer stem cell–mediated resistance and improve therapeutic outcomes in non-small cell lung cancer.
YU et al. (Fri,) studied this question.