Auranofin and Cold Atmospheric Plasma Synergize to Trigger Distinct Cell Death Mechanisms and Immunogenic Responses in Glioblastoma

Abstract

Targeting the redox balance of malignant cells via the delivery of high oxidative stress unlocks a potential therapeutic strategy against glioblastoma (GBM). We investigated a novel reactive oxygen species (ROS)-inducing combination treatment strategy, by increasing exogenous ROS via cold atmospheric plasma and inhibiting the endogenous protective antioxidant system via auranofin (AF), a thioredoxin reductase 1 (TrxR) inhibitor. The sequential combination treatment of AF and cold atmospheric plasma-treated PBS (pPBS), or AF and direct plasma application, resulted in a synergistic response in 2D and 3D GBM cell cultures, respectively. Differences in the baseline protein levels related to the antioxidant systems explained the cell-line-dependent sensitivity towards the combination treatment. The highest decrease of TrxR activity and GSH levels was observed after combination treatment of AF and pPBS when compared to AF and pPBS monotherapies. This combination also led to the highest accumulation of intracellular ROS. We confirmed a ROS-mediated response to the combination of AF and pPBS, which was able to induce distinct cell death mechanisms. On the one hand, an increase in caspase-3/7 activity, with an increase in the proportion of annexin V positive cells, indicates the induction of apoptosis in the GBM cells. On the other hand, lipid peroxidation and inhibition of cell death through an iron chelator suggest the involvement of ferroptosis in the GBM cell lines. Both cell death mechanisms induced by the combination of AF and pPBS resulted in a significant increase in danger signals (ecto-calreticulin, ATP and HMGB1) and dendritic cell maturation, indicating a potential increase in immunogenicity, although the phagocytotic capacity of dendritic cells was inhibited by AF. In vivo, sequential combination treatment of AF and cold atmospheric plasma both reduced tumor growth kinetics and prolonged survival in GBM-bearing mice. Thus, our study provides a novel therapeutic strategy for GBM to enhance the efficacy of oxidative stress-inducing therapy through a combination of AF and cold atmospheric plasma.

Design, Synthesis and Activity of New N1-Alkyl Tryptophan Functionalized Dendrimeric Peptides against Glioblastoma

“…The differences in sensitivity to each of the compounds observed between particular cell lines most likely result from the aforementioned biodiversity of cell lines used in this study. Indeed, several groups have documented a differential response of those three cell lines to various therapeutic approaches [ 55 , 56 , 57 , 58 ]. Here, compared to T98G and LN229 cells, U87MG cells turned out to be less susceptible to dendrimer-mediated toxicity, which was particularly pronounced in colony-forming assay.…”

Metal-based anticancer agents as immunogenic cell death inducers: the past, present, and future

“…In 2021, Deben et al 59 reported induction of ICD in glioblastoma cells via perturbation of ROS homeostasis through sequential combinatorial treatment of auranofin ( AF , Fig. 20) and cold atmospheric plasma treated phosphate buffered saline (pPBS).…”

Modulating the Antioxidant Response for Better Oxidative Stress-Inducing Therapies: How to Take Advantage of Two Sides of the Same Medal?

“…It has been reported that CAP-derived RONS (especially OH•) can be transported to millimeter depths to reach deep-seated diseased cells [237]. CAP has shown to induce a variety of biological effects, such as blood coagulation [238], tissue regeneration [237,239], sterilization [4,238,240], wound healing [15,228,238], cancer cell death [7,9,51,59,96,233,238,240,241], activation of immune cells [242,243], and virus inactivation [244,245]. The type and concentration of CAP-generated species delivered to cells depend on the CAP operating conditions, controlled by the design of the source, including the configuration of the electrodes.…”

“…These compounds induce cancer cell death by releasing electrons from the electron transport system (ETS) to O 2 by NADPH dehydrogenase, resulting in the formation of O 2 − . The oxidative stress caused by chemotherapeutic drugs interferes with cellular processes by changing the integrity of the cell membrane to cause cytotoxicity and thereby increasing their cytotoxic effect [7,51,243]. In addition, since some side effects caused by chemical agents appear to be prevented by certain antioxidants, administering these supplements during chemotherapy may diminish the development of side effects, as well as improve the response to therapy [256].…”