Plasma Treated Water Solutions in Cancer Treatments: The Contrasting Role of RNS.

Eloisa Sardella,Roberto Gristina,Marinella Striccoli,Francesco Fracassi,Savino Cosmai,Valeria Veronico,Pietro Favia,Loris Grossi,Maura Buttiglione

doi:10.3390/antiox10040605

Abstract

Plasma Treated Water Solutions (PTWS) recently emerged as a novel tool for the generation of Reactive Oxygen and Nitrogen Species (ROS and RNS) in liquids. The presence of ROS with a strong oxidative power, like hydrogen peroxide (H2O2), has been proposed as the main effector for the cancer-killing properties of PTWS. A protective role has been postulated for RNS, with nitric oxide (NO) being involved in the activation of antioxidant responses and cell survival. However, recent evidences proved that NO-derivatives in proper mixtures with ROS in PTWS could enhance rather than reduce the selectivity of PTWS-induced cancer cell death through the inhibition of specific antioxidant cancer defenses. In this paper we discuss the formation of RNS in different liquids with a Dielectric Barrier Discharge (DBD), to show that NO is absent in PTWS of complex composition like plasma treated (PT)-cell culture media used for in vitro experiments, as well as its supposed protective role. Nitrite anions (NO2-) instead, present in our PTWS, were found to improve the selective death of Saos2 cancer cells compared to EA.hy926 cells by decreasing the cytotoxic threshold of H2O2 to non-toxic values for the endothelial cell line.

Highlights

Non-Thermal Plasmas (NTP) are partially ionized gases consisting of chemically reactive species such as ions, neutrals, free radicals, electrons, UV-VIS radiation, and electric field
Our study is aimed at clarifying, from one side the routes of formation of RNS in Plasma Treated Water Solutions (PTWS) generated in bioactive liquids like Dulbecco Modified Eagle Medium (DMEM), and, on the other side, at demonstrating how the modulation of RNS concentrations in plasma treated (PT)-DMEM used incubation with cells effectively concurs to tune anticancer effects
We can conclude that Endothelial cells (EC) have a capability to overcome the oxidative stress differently from that of osteosarcoma cells. This cell susceptibility threshold and the concurrent action of H2 O2 and NO2 − was supposed by Bauer et al [65], and the results shown in our paper attest that an exogenous delivery of RNS in proper combination with ROS enhances the selectivity of oxidative stress induced in cancer cells

Summary

Introduction

Non-Thermal Plasmas (NTP) are partially ionized gases consisting of chemically reactive species such as ions, neutrals, free radicals, electrons, UV-VIS radiation, and electric field. Besides natural events, such as the Aurora Borealis, NTP can be generated by applying an electric field to a neutral gas. When nitrogen and oxygen feeds are used, NTP generate ROS and RNS. In this case, NTP are often tested for biomedical purposes through the exposure of biological targets directly to NTP [1] or to liquids or solutions enriched both with ROS and RNS (RONS) by means of NTP [2]. It is known that the most stable and abundant

Objectives

Methods

Results

Discussion

Conclusion