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

Area of Science:

• * Plasma medicine
• * Reactive Oxygen and Nitrogen Species (ROS and RNS) generation
• * Cancer cell death mechanisms

Background:

• * Plasma Treated Water Solutions (PTWS) utilize ROS and RNS for potential therapeutic applications.
• * Hydrogen peroxide (H₂O₂) in PTWS is considered a primary agent for cancer cell death.
• * Nitric oxide (NO) and its derivatives in PTWS have been investigated for their role in cell survival and cancer treatment selectivity.

Purpose of the Study:

• * To investigate the formation of RNS in various liquids using Dielectric Barrier Discharge (DBD).
• * To clarify the role of NO and nitrite anions (NO₂⁻) in PTWS, particularly in plasma-treated cell culture media.
• * To evaluate the impact of NO₂⁻ on the selective cytotoxicity of PTWS against cancer cells.

Main Methods:

• * Generation of PTWS using Dielectric Barrier Discharge (DBD).
• * Analysis of RNS composition in different liquid environments, including cell culture media.
• * In vitro experiments assessing the effects of PTWS on Saos2 cancer cells and EA.hy926 endothelial cells.

Main Results:

• * Nitric oxide (NO) was found to be absent in PTWS of complex composition, such as plasma-treated cell culture media.
• * Nitrite anions (NO₂⁻) were present in PTWS and demonstrated a role in enhancing selective cancer cell death.
• * NO₂⁻ decreased the cytotoxic threshold of H₂O₂, making it less toxic to endothelial cells while maintaining efficacy against cancer cells.

Conclusions:

• * The postulated protective role of NO in PTWS is questionable, especially in complex media.
• * Nitrite anions (NO₂⁻) in PTWS contribute to improved selectivity in cancer cell killing.
• * PTWS, particularly with the presence of NO₂⁻, offers a promising approach for targeted cancer therapy with reduced harm to healthy cells.