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

Abstract

Abstract 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 cell lines (HNC). Materials and 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, inhibition of cell proliferation by MTS assay, apoptosis occurrence and cell cycle modifications by flow cytometry were assessed on primary human gingival fibroblasts (hGF) and the HNC cell lines HSC2, HSC4 and A253. Results: All 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, hGF 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. Clinical Relevance: The present investigation represents a starting point to favour the clinical translation of CAP as a precision medicine tool by proposing an innovative method, namely ion chromatography, to standardize the quantification of plasma-derived RONS and proving its selectivity in inactivating tumor cells over non-malignant cells. These strategies could be applied to identify the optimal parameter configuration to achieve the desired treatment/therapeutic outcome and to aid the definition of clinical protocols.