Signal amplification by tumor cells: Clue to the understanding of the antitumor effects of cold atmospheric plasma and plasma-activated medium

Background: Application of cold atmospheric plasma to medium generates “plasma-activated medium” that induces apoptosis selectively in tumor cells and that has an antitumor effect in vivo. The underlying mechanisms are not well understood. Objective: Elucidation of potential chemical interactions within plasma-activated medium and of reactions of medium components with specific target structures of tumor cells should allow to define the active principle in plasma activated medium. Methods: Established knowledge of intercellular apoptosis-inducing reactive oxygen/nitrogen species-dependent signaling and its control by membrane-associated catalase and SOD was reviewed. Model experiments using extracellular singlet oxygen were analyzed with respect to catalase inactivation and their relevance for the antitumor action of cold atmospheric plasma. Potential interactions of this tumor cell-specific control system with components of plasma-activated medium or its reaction products were discussed within the scope of the reviewed signaling principles. Results: None of the long-lived species found in plasma-activated medium, such as nitrite and H2O2, nor OCl- or .NO seemed to have the potential to interfere with catalase-dependent control of apoptosis-inducing signaling of tumor cells when acting alone. However, the combination of H2O2 and nitrite might generate peroxynitrite. The protonation of peroxnitrite to peroxynitrous acid allows for the generation of hydroxyl radicals that react with H2O2, leading to the formation of hydroperoxide radicals. These allow for singlet oxygen generation and inactivation of membrane-associated catalase through an autoamplificatory mechanism, followed by intercellular apoptosis-inducing signaling. Conclusion: Nitrite and H2O2 in plasma-activated medium establish singlet oxygen-dependent interference selectively with the control system of tumor cells.

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Selective treatments of prostate tumor cells with a cold atmospheric plasma jet

Clinical Plasma Medicine ◽

10.1016/j.cpme.2020.100098 ◽

2020 ◽

Vol 17-18 ◽

pp. 100098 ◽

Cited By ~ 2

Author(s):

Mohamed Fofana ◽

Julio Buñay ◽

Florian Judée ◽

Silvère Baron ◽

Sébastien Menecier ◽

...

Keyword(s):

Tumor Cells ◽

Plasma Jet ◽

Prostate Tumor ◽

Atmospheric Plasma ◽

Cold Atmospheric Plasma ◽

Prostate Tumor Cells

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Biophysical Effects of Cold Atmospheric Plasma on Glial Tumor Cells

10.1007/978-3-319-06224-2 ◽

2014 ◽

Cited By ~ 1

Author(s):

Julia Köritzer

Keyword(s):

Tumor Cells ◽

Atmospheric Plasma ◽

Glial Tumor ◽

Cold Atmospheric Plasma ◽

Biophysical Effects

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Pyruvate as a cell‐protective agent during cold atmospheric plasma treatment in vitro: Impact on basic research for selective killing of tumor cells

Plasma Processes and Polymers ◽

10.1002/ppap.201900088 ◽

2019 ◽

Vol 16 (12) ◽

pp. 1900088 ◽

Cited By ~ 3

Author(s):

Claudia Bergemann ◽

Henrike Rebl ◽

Anik Otto ◽

Svenja Matschke ◽

Barbara Nebe

Keyword(s):

Plasma Treatment ◽

Tumor Cells ◽

Basic Research ◽

Atmospheric Plasma ◽

Protective Agent ◽

Cold Atmospheric Plasma ◽

A Cell

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COLD ATMOSPHERIC PLASMA DIFFERENTIALLY AFFECTS CELL RENEWAL AND DIFFERENTIATION OF STEM CELLS AND APC-DEFICIENT-DERIVED TUMOR CELLS IN INTESTINAL ORGANOIDS

10.1101/2021.10.13.464287 ◽

2021 ◽

Author(s):

Alia Hadefi ◽

Morgane Leprovots ◽

Max Thulliez ◽

Orianne Bastin ◽

Anne Lefort ◽

...

Keyword(s):

Stem Cells ◽

Tumor Cells ◽

Ex Vivo ◽

Biological Effects ◽

Three Dimensional ◽

Atmospheric Plasma ◽

Cell Renewal ◽

Epithelial Stem Cells ◽

Cold Atmospheric Plasma ◽

Ex Vivo Culture

Cold atmospheric plasma (CAP) treatment has been proposed as a potentially innovative therapeutic tool in the biomedical field, notably for cancer due to its proposed toxic selectivity on cancer cells versus healthy cells. In the present study, we addressed the relevance of three-dimensional organoid technology to investigate the biological effects of CAP on normal epithelial stem cells and tumor cells isolated from mouse small intestine. CAP treatment exerted dose-dependent cytotoxicity on normal organoids and induced major transcriptomic changes associated with global response to oxidative stress, fetal-like regeneration reprogramming and apoptosis-mediated cell death. Moreover, we explored the potential selectivity of CAP on tumor-like Apc-deficient versus normal organoids in the same genetic background. Unexpectedly, tumor organoids exhibited higher resistance to CAP treatment, correlating with higher antioxidant activity at baseline as compared to normal organoids. This pilot study suggests that the ex vivo culture system could be a relevant alternative model to further investigate translational medical applications of CAP technology.

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The synergistic effect between hydrogen peroxide and nitrite, two long-lived molecular species from cold atmospheric plasma, triggers tumor cells to induce their own cell death

Redox Biology ◽

10.1016/j.redox.2019.101291 ◽

2019 ◽

Vol 26 ◽

pp. 101291 ◽

Cited By ~ 21

Author(s):

Georg Bauer

Keyword(s):

Hydrogen Peroxide ◽

Cell Death ◽

Synergistic Effect ◽

Tumor Cells ◽

Molecular Species ◽

Atmospheric Plasma ◽

Cold Atmospheric Plasma

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Dynamics of Singlet Oxygen-Triggered, RONS-Based Apoptosis Induction after Treatment of Tumor Cells with Cold Atmospheric Plasma or Plasma-Activated Medium

Scientific Reports ◽

10.1038/s41598-019-50329-3 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 8

Author(s):

Georg Bauer ◽

Dominika Sersenová ◽

David B. Graves ◽

Zdenko Machala

Keyword(s):

Singlet Oxygen ◽

Tumor Cells ◽

Dynamic Process ◽

Bystander Effect ◽

Atmospheric Plasma ◽

Specific Response ◽

Apoptosis Induction ◽

Cold Atmospheric Plasma ◽

Low Efficiency ◽

Triggering Process

Abstract Treatment of tumor cells with cold atmospheric plasma (CAP) or with plasma-activated medium (PAM) leads to a biochemical imprint on these cells. This imprint is mediated by primary singlet oxygen, which is mainly generated through the interaction between CAP-derived H2O2 and NO2−. This imprint is induced with a low efficiency as local inactivation of a few membrane-associated catalase molecules. As sustained generation of secondary singlet oxygen by the tumor cells is activated at the site of the imprint, a rapid bystander effect-like spreading of secondary singlet oxygen generation and catalase inactivation within the cell population is thus induced. This highly dynamic process is essentially driven by NOX1 and NOS of the tumor cells, and finally leads to intercellular RONS-driven apoptosis induction. This dynamic process can be studied by kinetic analysis, combined with the use of specific inhibitors at defined time intervals. Alternatively, it can be demonstrated and quantified by transfer experiments, where pretreated cells are mixed with untreated cells and bystander signaling is determined. These studies allow to conclude that the specific response of tumor cells to generate secondary singlet oxygen is the essential motor for their self-destruction, after a singlet oxygen-mediated triggering process by CAP or PAM.

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Acidified Nitrite Contributes to the Antitumor Effect of Cold Atmospheric Plasma on Melanoma Cells

International Journal of Molecular Sciences ◽

10.3390/ijms22073757 ◽

2021 ◽

Vol 22 (7) ◽

pp. 3757

Author(s):

Tom Zimmermann ◽

Lisa A Gebhardt ◽

Lucas Kreiss ◽

Christin Schneider ◽

Stephanie Arndt ◽

...

Keyword(s):

Molecular Mechanisms ◽

Membrane Damage ◽

Melanoma Cells ◽

Atmospheric Plasma ◽

Active Components ◽

Antitumor Effects ◽

Cold Atmospheric Plasma ◽

Viability Analysis ◽

Cellular Effects ◽

The Impact

Cold atmospheric plasma (CAP) is partially ionized gas near room temperature with previously reported antitumor effects. Despite extensive research and growing interest in this technology, active components and molecular mechanisms of CAP are not fully understood to date. We used Raman spectroscopy and colorimetric assays to determine elevated nitrite and nitrate levels after treatment with a MiniFlatPlaster CAP device. Previously, we demonstrated CAP-induced acidification. Cellular effects of nitrite and strong extracellular acidification were assessed using live-cell imaging of intracellular Ca2+ levels, cell viability analysis as well as quantification of p21 and DNA damage. We further characterized these observations by analyzing established molecular effects of CAP treatment. A synergistic effect of nitrite and acidification was found, leading to strong cytotoxicity in melanoma cells. Interestingly, protein nitration and membrane damage were absent after treatment with acidified nitrite, thereby challenging their contribution to CAP-induced cytotoxicity. Further, phosphorylation of ERK1/2 was increased after treatment with both acidified nitrite and indirect CAP. This study characterizes the impact of acidified nitrite on melanoma cells and supports the importance of RNS during CAP treatment. Further, it defines and evaluates important molecular mechanisms that are involved in the cancer cell response to CAP.

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Cold Atmospheric Plasma and Plasma-Activated Medium Trigger RONS-Based Tumor Cell Apoptosis

Scientific Reports ◽

10.1038/s41598-019-50291-0 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 18

Author(s):

Georg Bauer ◽

Dominika Sersenová ◽

David B. Graves ◽

Zdenko Machala

Keyword(s):

Lipid Peroxidation ◽

Tumor Cell ◽

Tumor Cells ◽

Complex Interaction ◽

Atmospheric Plasma ◽

Apoptosis Induction ◽

Tumor Cell Apoptosis ◽

Cold Atmospheric Plasma ◽

Protective Membrane

Abstract The selective in vitro anti-tumor mechanisms of cold atmospheric plasma (CAP) and plasma-activated media (PAM) follow a sequential multi-step process. The first step involves the formation of primary singlet oxygen (1O2) through the complex interaction between NO2− and H2O2.1O2 then inactivates some membrane-associated catalase molecules on at least a few tumor cells. With some molecules of their protective catalase inactivated, these tumor cells allow locally surviving cell-derived, extracellular H2O2 and ONOO─ to form secondary 1O2. These species continue to inactivate catalase on the originally triggered cells and on adjacent cells. At the site of inactivated catalase, cell-generated H2O2 enters the cell via aquaporins, depletes glutathione and thus abrogates the cell’s protection towards lipid peroxidation. Optimal inactivation of catalase then allows efficient apoptosis induction through the HOCl signaling pathway that is finalized by lipid peroxidation. An identical CAP exposure did not result in apoptosis for nonmalignant cells. A key conclusion from these experiments is that tumor cell-generated RONS play the major role in inactivating protective catalase, depleting glutathione and establishing apoptosis-inducing RONS signaling. CAP or PAM exposure only trigger this response by initially inactivating a small percentage of protective membrane associated catalase molecules on tumor cells.

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