Non-Thermal Atmospheric Pressure Plasma Preferentially Induces Apoptosis in p53-Mutated Cancer Cells by Activating ROS Stress-Response Pathways

Non-thermal atmospheric pressure plasma (NTAPP) is an ionized gas at room temperature and has potential as a new apoptosis-promoting cancer therapy that acts by generating reactive oxygen species (ROS). However, it is imperative to determine its selectivity and standardize the components and composition of NTAPP. Here, we designed an NTAPP-generating apparatus combined with a He gas feeding system and demonstrated its high selectivity toward p53-mutated cancer cells. We first determined the proper conditions for NTAPP exposure to selectively induce apoptosis in cancer cells. The apoptotic effect of NTAPP was greater for p53-mutated cancer cells; artificial p53 expression in p53-negative HT29 cells decreased the pro-apoptotic effect of NTAPP. We also examined extra- and intracellular ROS levels in NTAPP-treated cells to deduce the mechanism of NTAPP action. While NTAPP-mediated increases in extracellular nitric oxide (NO) did not affect cell viability, intracellular ROS increased under NTAPP exposure and induced apoptotic cell death. This effect was dose-dependently reduced following treatment with ROS scavengers. NTAPP induced apoptosis even in doxorubicin-resistant cancer cell lines, demonstrating the feasibility of NTAPP as a potent cancer therapy. Collectively, these results strongly support the potential of NTAPP as a selective anticancer treatment, especially for p53-mutated cancer cells.

非热大气压等离子体（Non-thermal atmospheric pressure plasma, NTAPP）是一种室温下的电离气体，其通过产生活性氧物种（reactive oxygen species, ROS）发挥作用，有望成为一种新型的促细胞凋亡癌症治疗手段。然而，明确其治疗选择性并标准化NTAPP的组分与构成，仍是亟待解决的关键问题。本研究设计了一套结合氦气供气系统的NTAPP发生装置，并证实其对p53突变型癌细胞具有较高的治疗选择性。我们首先确定了NTAPP暴露的适宜条件，以实现癌细胞的选择性凋亡诱导。实验结果显示，p53突变型癌细胞的凋亡效应更为显著；在p53阴性的HT29细胞中人工表达p53，则会减弱NTAPP的促凋亡作用。我们还检测了NTAPP处理后细胞内外的ROS水平，以推导NTAPP的作用机制。研究发现，NTAPP介导的细胞外一氧化氮（nitric oxide, NO）水平升高并不会影响细胞活力，但NTAPP暴露下细胞内ROS水平上升，进而诱导细胞凋亡。该效应可通过ROS清除剂处理呈剂量依赖性地减弱。此外，NTAPP甚至可在阿霉素耐药癌细胞系中诱导凋亡，这证实了NTAPP作为强效癌症治疗手段的可行性。综上，上述研究结果有力支持了NTAPP作为选择性抗癌治疗手段的潜力，尤其针对p53突变型癌细胞。