Open-Air Cold Plasma Device Leads to Selective Tumor Cell Cytotoxicity

Abstract

The need for effective and safe therapies for cancer is growing as aging is modifying its epidemiology. Cold atmospheric plasma (CAP) has gained attention as a potential anti-tumor therapy. CAP is a gas with enough energy to ionize a significant fraction of its constituent particles, forming equal numbers of positive ions and electrons. Timely-resolved output voltage measurement, emission spectroscopy, and quantification of reactive species (RS) in plasma-activated media (PAM) were performed to characterize the physical and chemical properties of plasma. To assess the cytotoxicity of cold atmospheric plasma in human tumors, different cell lines were cultured, plated, and exposed to CAP, followed by MTT and SRB colorimetric assays 24 h later. Human fibroblasts, phenotypically normal cells, were processed similarly. Plasma cytotoxicity was higher in cells of breast cancer, urinary bladder cancer, osteosarcoma, lung cancer, melanoma, and endometrial cancer. Cytotoxicity was time-dependent and possibly related to the increased production of hydrogen peroxide in the exposed medium. Sixty seconds of CAP exposure renders selective effects, preserving the viability of fibroblast cells. These results point to the importance of conducting further studies of the therapy with plasma.

Cold Atmospheric Plasma Apoptotic and Oxidative Effects on MCF7 and HCC1806 Human Breast Cancer Cells

“…Our previous results have studied the effect of CAP exposure in metabolic activity and viability of MCF7 and HCC1806 cells [19]. By comparing the metabolic activity of several cell lines after plasma exposure, we observed that longer CAP exposures were required to reduce metabolic activity in breast cancer cells than most of the cells tested [19].…”

“…Our previous results have studied the effect of CAP exposure in metabolic activity and viability of MCF7 and HCC1806 cells [19]. By comparing the metabolic activity of several cell lines after plasma exposure, we observed that longer CAP exposures were required to reduce metabolic activity in breast cancer cells than most of the cells tested [19]. However, the effect of plasma treatment in the cells' viability differed between triplenegative (MCF7) and hormonal-receptor-positive (HCC1806) breast cancer cell lines.…”

“…Whichever the mechanism explaining the increase in metabolic index, plasma exposure to longer duration abolished this response. This work further explores the possible mechanisms of action of new plasma-based therapies in these breast cancer cell lines [19].…”

“…Recent studies suggest an interesting potential of cold atmospheric plasma (CAP) in cancer therapy, as demonstrated by the selective eradication of cancer cells in vitro [16][17][18][19][20]. Previously, we studied the effect of cold plasma in different human cancer cell lines including BC, melanoma, colon carcinoma and prostate cancer.…”

“…The results showed a significant decrease in cell viability in most cell lines. Particularly, the viability of BC cells decreased following only 90 s of CAP exposure [19]. Furthermore, a robust study involving direct and indirect CAP treatment of retinoblastoma cells and phenotypically normal counterparts suggests that this therapy has the potential to selectively ablate tumour cells [20].…”