P 170 - Pro-oxidant tumor therapy in murine melanoma and pancreatic cancer

Abstract

Despite recent advances in oncology, cancer is still among the most life threatening diseases. This requires furthering therapeutic approaches. Cold physical plasma is an ionized gas. Its biological active components are reactive oxygen and nitrogen species (ROS, RNS). Such species receive increasing recognition in pro‑oxidant tumor therapies. They are evident in chemo and radiation therapy in that antitumor immunity is often observed. We tested the efficacy of plasma‑derived oxidants in murine melanoma and pancreatic cancer. In vitro, B16 melanoma cells showed a decrease in metabolic activity, viability, cell growth, and cell migration. Cell death was confirmed in melanoma spheroid cultures. Plasma treatment upregulated MHC class I expression and calreticulin exposure. The latter is known to be important in conferring immunological cell death. Extended the findings to another cancer model, plasma‑treated murine PDA6606 pancreatic cancer cells also gave decrease in cellular activity and viability. In co-culture, macrophage motility was enhanced. In a syngeneic pancreatic cancer mouse model, peritoneal tumor nodes were frequently lavaged with plasma‑treated liquid. Treatment decreased lesion number and size, and increased cell apoptosis in tumors, macrophage infiltration, and animal survival. These results argue for role of pro‑oxidants in tumor therapy.