Nanosecond-Pulsed DBD Plasma-Generated Reactive Oxygen Species Trigger Immunogenic Cell Death in A549 Lung Carcinoma Cells through Intracellular Oxidative Stress

Abstract

A novel application for non-thermal plasma is the induction of immunogenic cancer cell death for cancer immunotherapy. Cells undergoing immunogenic death emit danger signals which facilitate anti-tumor immune responses. Although pathways leading to immunogenic cell death are not fully understood; oxidative stress is considered to be part of the underlying mechanism. Here; we studied the interaction between dielectric barrier discharge plasma and cancer cells for oxidative stress-mediated immunogenic cell death. We assessed changes to the intracellular oxidative environment after plasma treatment and correlated it to emission of two danger signals: surface-exposed calreticulin and secreted adenosine triphosphate. Plasma-generated reactive oxygen and charged species were recognized as the major effectors of immunogenic cell death. Chemical attenuators of intracellular reactive oxygen species successfully abrogated oxidative stress following plasma treatment and modulated the emission of surface-exposed calreticulin. Secreted danger signals from cells undergoing immunogenic death enhanced the anti-tumor activity of macrophages. This study demonstrated that plasma triggers immunogenic cell death through oxidative stress pathways and highlights its potential development for cancer immunotherapy.

New Hopes for Plasma-Based Cancer Treatment

“…A pulsed DBD with microsecond pulses was used for treatment of xenograft model mouse of human glioblastoma cells [23]. Recently, nanosecond-pulsed plasma have been developed as potential tools in cancer treatment [24,25].…”

“…Several recent studies have suggested that non-thermal plasma treatment induces ICD and stimulates macrophages [25,[33][34][35]. Non-thermal plasma treatment was shown to stimulate extracellular ATP secretion and enhance cell death via ICD-mediated macrophage stimulation.…”

Cold Atmospheric Plasma: A Powerful Tool for Modern Medicine

“…Miller et al [160] and Almeida [161] described the detailed principles and possibilities of plasma use in immunotherapy. In particular, the work by Lin et al [162] demonstrated that CAP should induce ICD in vitro in A549 lung cancer and radio-resistant nasopharyngeal carcinoma cell lines. Therein, extracellular ATP secretion was followed by ICD macrophage stimulation.…”

Non-Thermal Plasma Accelerates Astrocyte Regrowth and Neurite Regeneration Following Physical Trauma In Vitro

“…Immediately following mechanical disruption, the media was removed, and cells were washed with phosphate buffered saline (PBS). The PBS was then removed, and cultures were treated with NTP using a nanosecond-pulsed dielectric barrier discharge (nspDBD) system ( Figure 1B) [25].…”

“…Both electrodes used a nanosecond pulser (FPB-20-05NM, FID GmBH, Burbach, Germany) to generate a high voltage pulse (29 kV, 2 ns rise times, and 20 ns pulse width), and, therefore, the pulse characteristics were the same. While the electrode geometries are different, several studies have demonstrated that the NTP treatment energy is the most crucial effector of biological response with the DBD plasma system [25][26][27]. Therefore, both the voltage and current of the discharge in the system was measured and energy per plasma pulse for both electrodes was calculated as previously described [28]: 0.9 mJ/pulse for the flat DBD electrode and 1.6 mJ/pulse for the pen electrode.…”