In Vitro Anticancer Efficacy of Six Different Clinically Approved Types of Liquids Exposed to Physical Plasma

Colorectal cancer metastasis often occurs before clinical diagnosis and leads to diffuse spread of tumor nodules in the peritoneal cavity and peritoneal carcinomatosis. These small lesions are difficult to remove surgically and poor prognosis. Current options in palliation include ionizing radiation and hyperthermic intraperitoneal chemotherapy that lead to severe side effects. In previous research, oxidant-enriched solutions, like physical plasma-treated cell culture medium, showed therapeutic potential in diminishing cancer growth of peritoneal lesions. However, the applicability of cell culture medium in clinical settings is limited. To this end, we compared the tumor-toxic activity of six clinically approved liquids following plasma treatment in vitro in murine CT26 colorectal cancer cells. Changes and stability of pH-value and hydrogen peroxide (H2O2) were assessed. Exposing colorectal cancer cells to these physical plasma-treated liquids reduced their metabolic activity, and created a distinct morphological alterations and a reduction in cell motility. While some solutions such as Ringer’s lactate show good effects, we found plasma-treated sodium chloride (NaCl) to perform consistently well in terms of H2O2 stability and cytotoxicity. In conclusion, several of the investigated liquids may be suitable as plasma-treated liquid for anticancer peritoneal lavage with NaCl giving the best in vitro results in our hands.