Cold Atmospheric Plasma Selectively Induces Apoptosis In Renal Adenocarcinoma

The application of cold atmospheric plasma (CAP) in the selective treatment of cancer has drawn increasing attention. However, very few studies have focused on the selective effect of CAP towards cancer compared to the corresponding normal cells, among which the results have been mixed. Guerrero-Preston has shown that CAP selectively kills head and neck squamous cell carcinoma. While the normal oral cavity epithelial cells were killed to some degree, the mechanism of selectivity was not reported [1]. Breast cancer has been shown to be selectively killed relative to mesenchymal stem cells (MSCs) [2], however, no selectivity was found when compared to normal breast epithelial cells [3]. CAP induces apoptosis of lung cancer without affecting bronchial epithelial cells, but no apoptotic pathways were identified or proposed [4]. Ishaq et al. proposed NADPH oxidase (Nox2) as the endogenous ROS source which mediates the ROS level in different types of colon cancer and further induces various degrees of cell death, but this proposed pathway was not verified in normal colon cells [5]. We study the effects of helium cold atmospheric plasma using the Canady Helios Cold Plasma Scalpel on established renal adenocarcinoma and renal epithelial cell lines. Our data demonstrates that kidney adenocarcinoma (769-P) is selectively killed compared to renal epithelial cells (HPRCEC). DR4 (TRAIL-R1) expression was found to be significantly increased following CAP treatment, and may contribute to the selective induction of apoptosis. Differences in DR4 expression following CAP treatment may explain the inconsistent responses of various cell lines to CAP.