Evaluation of Inducing Apoptosis as Cell Death Mechanism by Cold Atmospheric Plasma in Cervix Cancer Cell Line (Hela)

Abstract

Background: Cancer is the second leading cause of death in the world and third in Iran. Various methods have been investigated for cancer treatment in which the use of cold atmospheric plasma and plasma-activated medium (PAM) are two new research methods in the field of cancer therapy. This study aimed to evaluate the inducing of apoptosis as cell death mechanism by cold atmospheric plasma in cervix cancer cell line (Hela) Methods: At first, the effects of helium and helium + oxygen atmospheric plasma and PAM on the viability of Hela cell line were investigated. Then, the rate of H2O2 in the medium, and the levels of caspase-3, caspase-8, Bcl-2-associated X (Bax), and B-cell lymphoma protein 2 (Bcl2) proteins in both direct plasma and PAM treatments were evaluated using MTT assay, medium H2O2 assay, and Western Blot analysis, respectively. Findings: The decrease of cells viability in direct plasma treatment group was more than PAM group (P < 0.001), and adding oxygen to plasma increased the rate of cell death. The H2O2 level in medium in direct method was more than PAM (P < 0.001). Moreover, the expression of caspase-3 and caspase-8 proteins in direct plasma were higher than PAM (P < 0.010). Higher ratio of Bcl-2/Bax showed the induction of apoptosis in cancer cells (P < 0.001). Conclusion: Cold atmospheric plasma is a source of oxygen and nitrogen reactive species, which can produce free radicals such as H2O2 in medium that plays an important role in the treatment of cancer. Moreover, direct plasma and PAM induce apoptosis in cancer cells, as a probable mechanism of cell death.

Keywords

• apoptosis
• cell viability
• reactive oxygen species
• reactive nitrogen species