Cold Atmospheric Plasma Selectively Targets Neuroblastoma: Mechanistic Insights and In Vivo Validation.

BACKGROUND: Neuroblastoma (NB) presents significant challenges in pediatric oncology, particularly in high-risk cases where local recurrence occurs in ~35% of patients. Cold Atmospheric Plasma (CAP) has emerged as a promising treatment due to its selective cytotoxicity toward cancer cells while sparing normal cells. METHODS: This study assessed CAP efficacy using in vitro NB cell lines (SK-N-AS and LAN-5) and in vivo xenograft murine models. In vitro, CAP was applied via a helium jet, and cellular responses were evaluated for viability, reactive oxygen species (ROS), lipid peroxidation, DNA damage, and cell cycle, while apoptosis was measured by Annexin V/PI flow cytometry. In vivo, CAP was applied to unresected tumors and residual tumors after incomplete resection. Tumor regrowth was monitored, and histological analysis was performed. RESULTS: CAP reduced NB cell viability in a dose- and time-dependent manner by increasing intracellular ROS and lipid peroxidation. CAP-treated NB cells showed a 50% rise in oxidative DNA damage, a two-fold increase in apoptosis, and alterations in cell-cycle progression, while normal fibroblasts showed modest effects. CAP predominantly induced apoptosis, though secondary necrosis appeared with prolonged exposures, consistent with caspase-3 and PARP pathways. In xenografts, CAP reduced tumor diameter by 60% and increased caspase-3-positive cells, with minimal effects on normal tissue. CONCLUSIONS: CAP demonstrates strong therapeutic potential as a targeted, non-invasive NB treatment, particularly for residual tumors near vascular structures with consistent exposure times (60-300 s).