Human osteosarcoma (OS) is the most common primary malignant bone tumor occurring most commonly in adolescents and young adults. Major improvements in disease-free survival have been achieved by implementing a combination therapy consisting of radical surgical resection of the tumor and systemic multi-agent chemotherapy. However, long-term survival remains poor, so novel targeted therapies to improve outcomes for patients with osteosarcoma remains an area of active research. This includes immunotherapy, photodynamic therapy, or treatment with nanoparticles. Cold atmospheric plasma (CAP), a highly reactive (partially) ionized physical state, has been shown to inherit a significant anticancer capacity, leading to a new field in medicine called “plasma oncology.” The current article summarizes the potential of CAP in the treatment of human OS and reviews the underlying molecular mode of action.

Background— Recent work has revealed an essential involvement of soluble CD40 ligand (sCD40L) in inflammation and atherosclerosis. We investigated whether sCD40L functionally affects peripheral blood–derived angiogenic early outgrowth cells (EOCs) and neointimal remodeling after arterial injury. Methods and Results— Besides myeloid and endothelial markers, cultured human EOCs strongly expressed CD40 mRNA and protein. EOC adhesion to fibronectin, fibrinogen, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 under flow conditions, as well as their transmigration toward stromal cell–derived factor-1α, was dose-dependently reduced after preincubation with recombinant human sCD40L for 24 hours. Integrin expression was unaffected by sCD40L, implying that integrin adhesiveness was attenuated. Surface-immobilized CD40L supported much lower adhesion of EOCs than fibronectin. Treatment of EOCs with sCD40L increased superoxide anion production and decreased viability and proliferation. Notably, CD40 ^−/− mice displayed reduced neointima and improved re-endothelialization after carotid wire injury compared with wild-type mice, and therapeutic infusion of control EOCs but not EOCs pretreated with sCD40L attenuated neointimal growth after wire injury in nude mice. Furthermore, neointimal growth was more markedly diminished by infusion of spleen-derived CD40 ^−/− mouse EOCs than by that of wild-type EOCs. Preincubation of wild-type EOCs but not CD40 ^−/− EOCs with sCD40L before their infusion markedly aggravated neointimal formation. Treatment with sCD40L attenuated luminal incorporation of EOCs and accelerated neointimal progression. Conclusions— Endothelial dysfunction due to persistently elevated plasma levels of sCD40L may be attributable to an impairment of EOC function. Hence, in the context of arterial injury, therapeutic blockade of sCD40L may provide a novel strategy for accelerating endothelial regeneration and attenuating neointimal remodeling.

Background/Aim: Cold atmospheric plasma has been shown to inhibit tumor cell growth and induce tumor cell death. The aim of the study was to investigate the effects of cold atmospheric plasma treatment on proliferation of human osteosarcoma cells and to characterize the underlying cellular mechanisms. Materials and Methods: Human osteosarcoma cells (U2-OS and MNNG/HOS) were treated with cold atmospheric plasma and seeded in culture plates. Cell proliferation, p53 and phospho-p53 protein expression and nuclear morphology were assessed. Results: The treated human osteosarcoma cell lines exhibited attenuated proliferation rates by up to 66%. The cells revealed an induction of p53, as well as phospho-p53 expression, by 2.3-fold and 4.5-fold, respectively, compared to controls. 4’,6-diamidino-2-phenylindole staining demonstrated apoptotic nuclear condensation following cold atmospheric plasma treatment. Conclusion: Cold atmospheric plasma treatment significantly attenuated cell proliferation in a preclinical in vitro osteosarcoma model. The resulting increase in p53 expression and phospho-activation in combination with characteristic nuclear changes indicate this was through induction of apoptosis.

Cold atmospheric plasma (CAP) interacting with tumor cells and finally leading to selective cell death has opened new horizons in cancer therapy. Despite significant progress in modern cancer treatment using immunologic and targeted therapies melanoma and glioblastoma presenting as brain metastases or primary tumor with poor prognosis are still a therapeutic challenge. The aim of the current study was to evaluate the potential of CAP (indirect treatment) in combination with the chemotherapeutics bleomycin, paclitaxel and dacarbazine to inhibit proliferation on human melanoma and glioblastoma cells in vitro. Cell lines of mouse melanoma (B16) were exposed for 1, 4, 12, 24 and 48 h, and of human melanoma (A375) and glioblastoma (A172) for 24 h to bleomycin, dacarbazine and paclitaxel together with plasma activated PBS. Directly after exposure cell proliferation after single (CAP, chemotherapeutic) or combined (CAP plus chemotherapeutic) treatment was assessed by cytotoxicity assay. Indirect CAP treatment of cell lines of glioblastoma and melanoma was followed by a strong reduction of proliferation most prominent after 24 h and 48 h exposure. With all drugs maximal reduction was achieved when drug-CAP combinations were used. Combination with CAP treating B16 melanoma cells reached 98% (48 h, combined with paclitaxel), A375 melanoma cells 82% (24 h, combined with bleomycin) and glioblastoma cells 96% (24 h, combined with paclitaxel). The combination of chemotherapy with CAP as indirect treatment may be beneficial in therapy of melanoma and glioblastoma by enhanced tumor reduction and less drug toxicity of chemotherapeutics.

Background: Cold atmospheric plasma (CAP) is increasingly used in the field of oncology. Many of the mechanisms of action of CAP, such as inhibiting proliferation, DNA breakage, or the destruction of cell membrane integrity, have been investigated in many different types of tumors. In this regard, data are available from both in vivo and in vitro studies. Not only the direct treatment of a tumor but also the influence on its blood supply play a decisive role in the success of the therapy and the patient’s further prognosis. Whether the CAP influences this process is unknown, and the first indications in this regard are addressed in this study. Methods: Two different devices, kINPen and MiniJet, were used as CAP sources. Human endothelial cell line HDMEC were treated directly and indirectly with CAP, and growth kinetics were performed. To indicate apoptotic processes, caspase-3/7 assay and TUNEL assay were used. The influence of CAP on cellular metabolism was examined using the MTT and glucose assay. After CAP exposure, tube formation assay was performed to examine the capillary tube formation abilities of HDMEC and their migration was messured in separate assays. To investigate in a possible mutagenic effect of CAP treatment, a hypoxanthine-guanine-phosphoribosyl-transferase assay with non malignant cell (CCL-93) line was performed. Results: The direct CAP treatment of the HDMEC showed a robust growth-inhibiting effect, but the indirect one did not. The MMT assay showed an apparent reduction in cell metabolism in the first 24 h after CAP treatment, which appeared to normalize 48 h and 72 h after CAP application. These results were also confirmed by the glucose assay. The caspase 3/7 assay and TUNEL assay showed a significant increase in apoptotic processes in the HDMEC after CAP treatment. These results were independent of the CAP device. Both the migration and tube formation of HDMEC were significant inhibited after CAP-treatment. No malignant effects could be demonstrated by the CAP treatment on a non-malignant cell line.

Background/Aim: To evaluate the potential involvement of redox-specific signalling pathways in cold atmospheric plasma (CAP)-induced apoptosis on human osteosarcoma cells. Materials and Methods: Osteosarcoma cell lines were treated with CAP with or without antioxidative agents and seeded in cell culture plates. Cell proliferation was determined by counting viable cells. Carrier gas-treated cells served as control. Peroxiredoxin (PRX) 1-3 expression and secretion were assessed. Results: CAP treatment exhibited strongly attenuated proliferation rates. This effect was significantly attenuated by the addition of N-acetylcysteine (NAC). CAP-treated cells exhibited an increase of PRX 1 and 2 10 sec after treatment. The ratio of oxidized to reduced PRX1 and PRX2 was significantly altered with increasing cellular concentration of the oxidized dimer. Conclusion: Antioxidant supplementation with NAC increases proliferation of CAP-treated osteosarcoma cells, implicating an involvement of redox signalling. Activation of PRX1 and -2 indicate CAP affects redox homeostasis.