Activation of Murine Immune Cells upon Co-culture with Plasma-treated B16F10 Melanoma Cells

Katrin Rödder,Juliane Moritz,Hans-Robert Metelmann,Klaus-Dieter Weltmann,Vandana Miller,Sander Bekeschus,Rajesh Gandhirajan

doi:10.3390/app9040660

Abstract

Recent advances in melanoma therapy increased median survival in patients. However, death rates are still high, motivating the need of novel avenues in melanoma treatment. Cold physical plasma expels a cocktail of reactive species that have been suggested for cancer treatment. High species concentrations can be used to exploit apoptotic redox signaling pathways in tumor cells. Moreover, an immune-stimulatory role of plasma treatment, as well as plasma-killed tumor cells, was recently proposed, but studies using primary immune cells are scarce. To this end, we investigated the role of plasma-treated murine B16F10 melanoma cells in modulating murine immune cells’ activation and marker profile. Melanoma cells exposed to plasma showed reduced metabolic and migratory activity, and an increased release of danger signals (ATP, CXCL1). This led to an altered cytokine profile with interleukin-1β (IL-1β) and CCL4 being significantly increased in plasma-treated mono- and co-cultures with immune cells. In T cells, plasma-treated melanoma cells induced extracellular signal-regulated Kinase (ERK) phosphorylation and increased CD28 expression, suggesting their activation. In monocytes, CD115 expression was elevated as a marker for activation. In summary, here we provide proof of concept that plasma-killed tumor cells are recognized immunologically, and that plasma exerts stimulating effects on immune cells alone.

Highlights

Melanoma incidence rapidly increased over the last decades [1], and malignant melanoma is the most lethal form of skin cancer today [2]
The melanoma cell metabolic activity increased with increasing FCS concentration (Figure 1c)
Our aim was to identify activation signatures in murine immune cells derived from spleen that had been co-cultured with plasma-treated melanoma cells

Summary

Introduction

Melanoma incidence rapidly increased over the last decades [1], and malignant melanoma is the most lethal form of skin cancer today [2]. Complicating its clinical treatment, the heterogeneity of malignant melanoma challenges the design of effective anti-tumor therapies [3]. Gold standard approaches in treatment and palliation include surgery, radiation therapy, chemotherapy, electrochemotherapy, adoptive cell transfer strategies, and immunotherapy [4,5,6,7]. The outstanding success of immunotherapies awarded with the Nobel Prize for Medicine and Physiology 2018 has provided compelling clinical evidence that the immune system plays a critical role in tumor defense [8]. Plasma treatment itself can exert effects on immune cells [10,11,12]

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