Atmospheric-Pressure Plasma Jet Induces Apoptosis Involving Mitochondria via Generation of Free Radicals

Hak Jun Ahn,Geunyoung Kim,Kang Il Kim,Sang Sik Yang,Jong-Soo Lee,Eunpyo Moon,Boris Zhivotovsky

doi:10.1371/journal.pone.0028154

Abstract

The plasma jet has been proposed as a novel therapeutic method for anticancer treatment. However, its biological effects and mechanism of action remain elusive. Here, we investigated its cell death effects and underlying molecular mechanisms, using air and N2 plasma jets from a micro nozzle array. Treatment with air or N2 plasma jets caused apoptotic death in human cervical cancer HeLa cells, simultaneously with depolarization of mitochondrial membrane potential. In addition, the plasma jets were able to generate reactive oxygen species (ROS), which function as surrogate apoptotic signals by targeting the mitochondrial membrane potential. Antioxidants or caspase inhibitors ameliorated the apoptotic cell death induced by the air and N2 plasma jets, suggesting that the plasma jet may generate ROS as a proapoptotic cue, thus initiating mitochondria-mediated apoptosis. Taken together, our data suggest the potential employment of plasma jets as a novel therapy for cancer.

Highlights

Apoptosis, one of the major types of cell death, can be modulated by programmed control mechanisms
Several intracellular signals can converge on mitochondria to induce mitochondrial swelling or increase mitochondrial membrane permeability (MMP), which causes the dissipation of mitochondrial transmembrane potential (Dym) and the release of proapoptotic factors, including cytochrome c
We show that micro plasma jet nozzle array generate reactive oxygen species (ROS) that may act as an apoptotic stimulus by inducing altered MMP in human cervical carcinoma HeLa cells

Summary

Introduction

One of the major types of cell death, can be modulated by programmed control mechanisms. The atmospheric-pressure plasma jet can generate ROS such as ozone, atomic oxygen, superoxide, peroxide, and hydroxyl radicals but it is not known whether the ROS generated by plasma jets can mediate apoptosis of mammalian cancer cells or whether the plasma-induced apoptotic processes involve mitochondria.

Results

Conclusion