PO-030 Cold atmospheric plasma treatment in breast cancer

Abstract

Introduction Breast cancer has a high incidence rate worldwide with about 1.67 million new cases. The need for new, effective and free of side effects therapies is growing as ageing is modifying the epidemiology of cancer. Cold atmospheric plasma (CAP), known as the fourth state of matter, a gas with enough energy to ionise a significant fraction of particles, has come into attention as a potential anti-tumour therapy. Our previous studies showed that CAP determined the decrease of breast cancer cells viability after an exposure of only 60 s. The goal of this study was to evaluate the effect of cold atmospheric plasma on breast cancer cell line based on reactive oxygen species (ROS), types of cell death and cell cycle. Material and methods In this study, we used a hormonal receptor positive breast cancer (MCF7). Cells were cultured, plated and exposed to CAP, for different periods of time: 60 and 120 s and, using a homemade CAP ejector. To assess ROS intracellular concentration, cell cultures were evaluated through specific probes, namely 2’,7’-dichlorodihydrofluorescein diacetate (DCFH2-DA) and dihydroetide (DHE). The levels of glutathione antioxidant defense (GSH) were also evaluated and all studies were performed 2 and 24 hours after CAP exposure. The cell death type and cell cycle were assessed by flow cytometry using Annexin V/propidium iodide (PI) and PI, respectively. Currently, we are performing the same studies in triple negative breast cancer cell line (HCC1806). Results and discussions After 2 hours of CAP therapy, ROS levels do not show any variation compared to the control. Intracellular content of superoxide anion was of (97.36±11.64)% on MCF7 cell line exposed to CAP for 120 s. However, after 24 hours the superoxide anion content was (87.92±21.13)%. Levels of glutathione remained similar to the control. Our preliminary results suggest that apoptosis is the most prevalent type of death and treated cells are predominantly in G0/G1 phase. Conclusion Levels of oxidative stress and antioxidant defenses suggest that other events besides ROS formation might be involved in the plasma effect on breast cancer cells. The results obtained encourage further studies. Funding FCT, Portugal (UID/NEU/04539/2013), FEDER-COMPETE (FCOMP-01–0124-FEDER-028417, POCI-01–0145-FEDER-007440)