Cold atmospheric plasma activated media selectively affects human head and neck cancer cell lines

Objective: Cold atmospheric plasma (CAP) is a novel therapeutic approach for cancer treatment. It can be used to treat liquids – plasma-activated media (PAM) - which are then transferred to the target as an exogenous source of reactive oxygen and nitrogen species (RONS). The present study aimed at chemically characterizing different PAM and assessing their in vitro selectivity against head and neck cancer cells (HNC). Methods: PAM were obtained by exposing 2 and 5 mL of medium to CAP for 5, 10 and 20 minutes at a 6 mm working distance. Anions kinetics was evaluated by ion chromatography. In addition, the inhibition of cell proliferation by MTS assaying, while apoptosis occurrence and cell cycle modifications were assessed by flow cytometry on human epidermal keratinocytes (HaCaT) and HNC cell lines including HSC2, HSC4 and A253. . Results: The 2 mL conditions showed a significant reduction in cell proliferation whereas for the 5 mL the effect was milder, but the time-dependence was more evident. In addition, HaCaT were unaffected by the 5 mL PAM, indicating a selectivity for cancer cells. Conclusions: The media chemical composition modified by CAP exposure influenced cell proliferation by modulating cell cycle and inducing apoptosis in cancer cells, without affecting normal cells.