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

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.

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.

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.

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).