A Review on the Selective Apoptotic Effect of Nonthermal Atmospheric-Pressure Plasma on Cancer Cells

Abstract

Nonthermal atmospheric-pressure plasma (NTAPP) is defined as a partially ionized gas containing electrically charged particles. Due to its low temperature and generation in atmospheric pressure, NTAPP has been useful for biomedical applications such as sterilization and wound healing. Recently, several groups have reported that NTAPP is able to induce apoptosis selectively in cancer cells, which opens a new discussion regarding whether NTAPP can be a competitive cancer therapy. Although most research has continued with in vitro experiments, a few groups have already demonstrated that NTAPP can be applied to xenograft mouse models to decrease the size of tumors. However, the mechanism of how the NTAPP efficiently induces apoptosis in cancer cells is not well understood. Results of current studies strongly suggest reactive oxygen species (ROS) and reactive nitrogen species (RNS) to be the primary components that induce DNA double-strand breaks (DSBs) to cause apoptosis. Cancer cells are, in general, defective in genes responsible for cell cycle control. Thus, the effect of NTAPP on the signaling and checkpoint pathways to control the cell cycle should be examined to understand the molecular mechanism of the selective apoptosis by NTAPP. This review evaluates the selective effect of NTAPP on cancer cells and their molecular mechanisms; our results support the potential of NTAPP as an efficient anticancer therapy in near future.