Reactive Species from Cold Atmospheric Plasma: Implications for Cancer Therapy

Abstract

Cold atmospheric plasmas (CAP) formed in air generate reactive oxygen and nitrogen species (RONS). RONS are biologically and therapeutically active agents and experimental evidence suggests that air plasmas shrink tumors by increasing oxidative and nitrosative stress on neoplastic tissue. Most mainline anti‐cancer therapies – including ionizing radiation and chemotherapies – also operate primarily via this pro‐oxidant, oxidative, and nitrosative stress mechanism. The main disadvantage of these conventional therapies is the development of treatment‐resistant cells. A key question for plasma cancer therapies is therefore whether or not cold plasma will lead to similar oxidative stress resistance. However, there are hints that combining nitrosative stress with oxidative stress via air plasma might avoid this problem. Plasma‐based cancer treatment may be a powerful and practical anti‐cancer agent, acting either alone or in combination with other therapies.

Plasma-induced selectivity in bone cancer cells death

“…APP formed in air generates reactive oxygen (ROS) and nitrogen species (RNS). These species appear to induce cell cycle arrest at relatively low plasma "doses", lead to apoptosis at higher doses 4 , and ultimately cause necrosis at the highest doses 5 . Furthermore, a remarkable similarity of anti-tumor action for all types of cancers investigated was observed:…”

Oxy-nitroso shielding burst model of cold atmospheric plasma therapeutics

“…The potentially re-sensitizing role of CAP-generated nitrosative stress as a potential advantage of CAP for cancer therapy was discussed in a recent review. [62] …”

“…[3,62] Anti-cancer agents (other than CAP) that act by raising tumor oxidative stress include radiotherapy [63]; photodynamic therapy [64]; many chemotherapeutic drugs [65,66]; and hyperthermia [67,68]. Antiinfective drugs, including many antibiotics [69]; antifungals [70]; and anti-parasitics [71] are known to act, at least in part, by raising oxidative stress in infected cells.…”

Plasma effects on the generation of reactive oxygen and nitrogen species in cancer cells in-vitro exposed by atmospheric pressure pulsed plasma jets

“…11 There is substantial literature on the role of NO and related compounds as a direct cancer therapy. 12,13 These studies provided evidence of an important tumor apoptotic intercellular signaling mechanism involving NO and ONOO À . [12][13][14] In plasma exposure to cells in vitro, the interaction of plasma species (excited neutral species and ions) with medium results in the generation of reactive species which can produce biologically important processes.…”

“…12,13 These studies provided evidence of an important tumor apoptotic intercellular signaling mechanism involving NO and ONOO À . [12][13][14] In plasma exposure to cells in vitro, the interaction of plasma species (excited neutral species and ions) with medium results in the generation of reactive species which can produce biologically important processes. Therefore, it is necessary to consider the interaction between a plasma jet and the liquid phase, particularly in the cell culture environment.…”