Search Results
Plasma treatment limits cutaneous squamous cell carcinoma development in vitro and in vivo
Cutaneous squamous cell carcinoma (SCC) is the most prevalent cancer worldwide, increasing the cost of healthcare services and with a high rate of morbidity. Its etiology is linked to chronic ultraviolet (UV) exposure that leads to malignant transformation of keratinocytes. Invasive growth and metastasis are severe consequences of this process. Therapy-resistant and highly aggressive SCC is frequently fatal, exemplifying the need for novel treatment strategies. Cold physical plasma is a partially ionized gas, expelling therapeutic doses of reactive oxygen and nitrogen species that were investigated for their anticancer capacity against SCC in vitro and SCC-like lesions in vivo. Using the kINPen argon plasma jet, a selective growth-reducing action of plasma treatment was identified in two SCC cell lines in 2D and 3D cultures. In vivo, plasma treatment limited the progression of UVB-induced SSC-like skin lesions and dermal degeneration without compromising lesional or non-lesional skin. In lesional tissue, this was associated with a decrease in cell proliferation and the antioxidant transcription factor Nrf2 following plasma treatment, while catalase expression was increased. Analysis of skin adjacent to the lesions and determination of global antioxidant parameters confirmed the local but not systemic action of the plasma anticancer therapy in vivo. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Molecular mechanisms of the efficacy of cold atmospheric pressure plasma (CAP) in cancer treatment
Recently, the potential use of cold atmospheric pressure plasma (CAP) in cancer treatment has gained increasing interest. Especially the enhanced selective killing of tumor cells compared to normal cells has prompted researchers to elucidate the molecular mechanisms for the efficacy of CAP in cancer treatment. This review summarizes the current understanding of how CAP triggers intracellular pathways that induce growth inhibition or cell death. We discuss what factors may contribute to the potential selectivity of CAP towards cancer cells compared to their non-malignant counterparts. Furthermore, the potential of CAP to trigger an immune response is briefly discussed. Finally, this overview demonstrates how these concepts bear first fruits in clinical applications applying CAP treatment in head and neck squamous cell cancer as well as actinic keratosis. Although significant progress towards understanding the underlying mechanisms regarding the efficacy of CAP in cancer treatment has been made, much still needs to be done with respect to different treatment conditions and comparison of malignant and non-malignant cells of the same cell type and same donor. Furthermore, clinical pilot studies and the assessment of systemic effects will be of tremendous importance towards bringing this innovative technology into clinical practice. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Concept for improved handling ensures effective contactless plasma treatment of patients with kINPen® MED
The nursing of patients with wounds is an essential part of medical healthcare. In this context, cold atmospheric-pressure plasma sources can be applied for skin decontamination and stimulation of wound healing. One of these plasma devices is the commercially available kINPen® MED (neoplas tools GmbH), a cold atmospheric-pressure plasma jet which is approved as a medical device, class-IIa. For the plasma treatment, a sterile disposable spacer is recommended to ensure a constant and effective distance between plasma and skin. The disadvantage of this spacer is its form and size which means that the effective axis/area is not visible for the attending doctor or qualified personnel and consequently it is a more or less intuitive treatment. In addition, the suggested perpendicular treatment is not applicable for the attending specialist due to lack of space or patient/wound positioning. A concept of a sensory unit was developed to measure the treatment distance and to visualize the effective treatment area for different angles. To determine the effective area for the plasma treatment, some exemplary methods were performed. Thus, the antimicrobial (Staphylococcus aureus DSM799/ATCC6538) efficacy, reactive oxygen species (ROS) distribution and (vacuum) ultraviolet ((V)UV) irradiation were determined depending on the treatment angle. Finally, a simplified first approach to visualize the effective treatment area at an optimal distance was designed and constructed to train attending specialists for optimal wound area coverage. © 2020 by the authors.
Risk Evaluation of EMT and Inflammation in Metastatic Pancreatic Cancer Cells Following Plasma Treatment
The requirements for new technologies to serve as anticancer agents go far beyond their toxicity potential. Novel applications also need to be safe on a molecular and patient level. In a broader sense, this also relates to cancer metastasis and inflammation. In a previous study, the toxicity of an atmospheric pressure argon plasma jet in four human pancreatic cancer cell lines was confirmed and plasma treatment did not promote metastasis in vitro and in ovo. Here, these results are extended by additional types of analysis and new models to validate and define on a molecular level the changes related to metastatic processes in pancreatic cancer cells following plasma treatment in vitro and in ovo. In solid tumors that were grown on the chorion-allantois membrane of fertilized chicken eggs (TUM-CAM), plasma treatment induced modest to profound apoptosis in the tissues. This, however, was not associated with a change in the expression levels of adhesion molecules, as shown using immunofluorescence of ultrathin tissue sections. Culturing of the cells detached from these solid tumors for 6d revealed a similar or smaller total growth area and expression of ZEB1, a transcription factor associated with cancer metastasis, in the plasma-treated pancreatic cancer tissues. Analysis of in vitro and in ovo supernatants of 13 different cytokines and chemokines revealed cell line-specific effects of the plasma treatment but a noticeable increase of, e.g., growth-promoting interleukin 10 was not observed. Moreover, markers of epithelial-to-mesenchymal transition (EMT), a metastasis-promoting cellular program, were investigated. Plasma-treated pancreatic cancer cells did not present an EMT-profile. Finally, a realistic 3D tumor spheroid co-culture model with pancreatic stellate cells was employed, and the invasive properties in a gel-like cellular matrix were investigated. Tumor outgrowth and spread was similar or decreased in the plasma conditions. Altogether, these results provide valuable insights into the effect of plasma treatment on metastasis-related properties of cancer cells and did not suggest EMT-promoting effects of this novel cancer therapy. © Copyright © 2020 Freund, Spadola, Schmidt, Privat-Maldonado, Bogaerts, von Woedtke, Weltmann, Heidecke, Partecke, Käding and Bekeschus.
Combination treatment with cold physical plasma and pulsed electric fields augments ros production and cytotoxicity in lymphoma
New approaches in oncotherapy rely on the combination of different treatments to enhance the efficacy of established monotherapies. Pulsed electric fields (PEFs) are an established method (electrochemotherapy) for enhancing cellular drug uptake while cold physical plasma is an emerging and promising anticancer technology. This study aimed to combine both technologies to elucidate their cytotoxic potential as well as the underlying mechanisms of the effects observed. An electric field generator (0.9–1.0 kV/cm and 100-μs pulse duration) and an atmospheric pressure argon plasma jet were employed for the treatment of lymphoma cell lines as a model system. PEF but not plasma treatment induced cell membrane permeabilization. Additive cytotoxicity was observed for the metabolic activity and viability of the cells while the sequence of treatment in the combination played only a minor role. Intriguingly, a parallel combination was more effective compared to a 15-min pause between both treatment regimens. A combination effect was also found for lipid peroxidation; however, none could be observed in the cytosolic and mitochondrial reactive oxygen species (ROS) production. The supplementation with either antioxidant, a pan-caspase-inhibitor or a ferroptosis inhibitor, all partially rescued lymphoma cells from terminal cell death, which contributes to the mechanistic understanding of this combination treatment. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Plasma treatment limits human melanoma spheroid growth and metastasis independent of the ambient gas composition
Melanoma skin cancer is still a deadly disease despite recent advances in therapy. Previous studies have suggested medical plasma technology as a promising modality for melanoma treatment. However, the efficacy of plasmas operated under different ambient air conditions and the comparison of direct and indirect plasma treatments are mostly unexplored for this tumor entity. Moreover, exactly how plasma treatment affects melanoma metastasis has still not been explained. Using 3D tumor spheroid models and high-content imaging technology, we addressed these questions by utilizing one metastatic and one non-metastatic human melanoma cell line targeted with an argon plasma jet. Plasma treatment was toxic in both cell lines. Modulating the oxygen and nitrogen ambient air composition (100/0, 75/25, 50/50, 25/75, and 0/100) gave similar toxicity and reduced the spheroid growth for all conditions. This was the case for both direct and indirect treatments, with the former showing a treatment time-dependent response while the latter resulted in cytotoxicity with the longest treatment time investigated. Live-cell imaging of in-gel cultured spheroids indicated that plasma treatment did not enhance metastasis, and flow cytometry showed a significant modulation of S100A4 but not in any of the five other metastasis-related markers (β-catenin, E-cadherin, LEF1, SLUG, and ZEB1) investigated. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Peroxynitrous Acid Generated In Situ from Acidified H2O2 and NaNO2. A Suitable Novel Antimicrobial Agent?
Peroxynitrite (ONOO−) and peroxynitrous acid (ONOOH) are known as short acting reactive species with nitrating and oxidative properties, which are associated with their antimicrobial effect. However, to the best of our knowledge, ONOOH/ONOO- are not yet used as antimicro-bial actives in practical applications. The aim is to elucidate if ONOOH generated in situ from acidified hydrogen peroxide (H2O2 ) and sodium nitrite (NaNO2 ) may serve as an antimicrobial active in disinfectants. Therefore, the dose-response relationship and mutagenicity are investigated. Antimicrobial efficacy was investigated by suspension tests and mutagenicity by the Ames test. Tests were conducted with E. coli. For investigating the dose-response relationship, pH values and concentrations of H2O2 and NaNO2 were varied. The antimicrobial efficacy is correlated to the dose of ONOOH, which is determined by numerical computations. The relationship can be described by the efficacy parameter W, corresponding to the amount of educts consumed during exposure time. Sufficient inactivation was observed whenever W ≥ 1 mM, yielding a criterion for inactivation of E. coli by acidified H2O2 and NaNO2 . No mutagenicity of ONOOH was noticed. While further investigations are necessary, results indicate that safe and effective usage of ONOOH generated from acidified H2O2 and NaNO2 as a novel active in disinfectants is conceivable. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Long-term Risk Assessment for Medical Application of Cold Atmospheric Pressure Plasma
Despite increasing knowledge gained based on multidisciplinary research, plasma medicine still raises various questions regarding specific effects as well as potential risks. With regard to significant statements about in vivo applicability that cannot be prognosticated exclusively based on in vitro data, there is still a deficit of clinical data. This study included a clinical follow-up of five probands who had participated five years previously in a study on the influence of cold atmospheric pressure plasma (CAP) on the wound healing of CO2 laser-induced skin lesions. The follow-up included a complex imaging diagnostic involving dermatoscopy, confocal laser scanning microscopy (CLSM) and hyperspectral imaging (HSI). Hyperspectral analysis showed no relevant microcirculatory differences between plasma-treated and non-plasma-treated areas. In summary of all the findings, no malignant changes, inflammatory reactions or pathological changes in cell architecture could be detected in the plasma-treated areas. These unique in vivo long-term data contribute to a further increase in knowledge about important safety aspects in regenerative plasma medicine. However, to confirm these findings and secure indication-specific dose recommendations, further clinical studies are required. © 2020 by the authors.
Risk assessment of kINPen plasma treatment of four human pancreatic cancer cell lines with respect to metastasis
Cold physical plasma has limited tumor growth in many preclinical models and is, therefore, suggested as a putative therapeutic option against cancer. Yet, studies investigating the cells’ metastatic behavior following plasma treatment are scarce, although being of prime importance to evaluate the safety of this technology. Therefore, we investigated four human pancreatic cancer cell lines for their metastatic behavior in vitro and in chicken embryos (in ovo). Pancreatic cancer was chosen as it is particularly metastatic to the peritoneum and systemically, which is most predictive for outcome. In vitro, treatment with the kINPen plasma jet reduced pancreatic cancer cell activity and viability, along with unchanged or decreased motility. Additionally, the expression of adhesion markers relevant for metastasis was down-regulated, except for increased CD49d. Analysis of 3D tumor spheroid outgrowth showed a lack of plasma-spurred metastatic behavior. Finally, analysis of tumor tissue grown on chicken embryos validated the absence of an increase of metabolically active cells physically or chemically detached with plasma treatment. We conclude that plasma treatment is a safe and promising therapeutic option and that it does not promote metastatic behavior in pancreatic cancer cells in vitro and in ovo. © 2019 by the authors.
Cold argon plasma as adjuvant tumour therapy on progressive head and neck cancer: A preclinical study
Investigating cold argon plasma (CAP) for medical applications is a rapidly growing, innovative field of research. The controllable supply of reactive oxygen and nitrogen species through CAP has the potential for utilization in tumour treatment. Maxillofacial surgery is limited if tumours grow on vital structures such as the arteria carotis. Here CAP could be considered as an option for adjuvant intraoperative tumour therapy especially in the case of squamous cell carcinoma of the head and neck. Further preclinical research is necessary to investigate the efficacy of this technology for future clinical applications in cancer treatment. Initially, a variety of in vitro assays was performed on two cell lines that served as surrogate for the squamous cell carcinoma (SCC) and healthy tissue, respectively. Cell viability, motility and the activation of apoptosis in SCC cells (HNO97) was compared with those in normal HaCaT keratinocytes. In addition, induction of apoptosis in ex vivo CAP treated human tissue biopsies of patients with tumours of the head and neck was monitored and compared to healthy control tissue of the same patient. In response to CAP treatment, normal HaCaT keratinocytes differed significantly from their malignant counterpart HNO97 cells in cell motility only whereas cell viability remained similar. Moreover, CAP treatment of tumour tissue induced more apoptotic cells than in healthy tissue that was accompanied by elevated extracellular cytochrome c levels. This study promotes a future role of CAP as an adjuvant intraoperative tumour therapy option in the treatment of head and neck cancer. Moreover, patient-derived tissue explants complement in vitro examinations in a meaningful way to reflect an antitumoral role of CAP. © 2019 by the authors.