Cold atmospheric plasma inhibits the growth of osteosarcoma cells by inducing apoptosis, independent of the device used

Current Status and Future Trends of Cold Atmospheric Plasma as an Oncotherapy

Cold atmospheric plasma (CAP), a redox modulation tool, is capable of inhibiting a wide spectrum of cancers and has thus been proposed as an emerging onco-therapy. However, with incremental successes consecutively reported on the anticancer efficacy of CAP, no consensus has been made on the types of tumours sensitive to CAP due to the different intrinsic characteristics of the cells and the heterogeneous design of CAP devices and their parameter configurations. These factors have substantially hindered the clinical use of CAP as an oncotherapy. It is thus imperative to clarify the tumour types responsive to CAP, the experimental models available for CAP-associated investigations, CAP administration strategies and the mechanisms by which CAP exerts its anticancer effects with the aim of identifying important yet less studied areas to accelerate the process of translating CAP into clinical use and fostering the field of plasma oncology.

Adjuvant composite cold atmospheric plasma therapy increases antitumoral effect of doxorubicin hydrochloride

Introduction

Cancer is a global health concern, with a significant impact on mortality rates. Despite advancements in targeted antitumor drugs, the development of new therapies remains challenging due to high costs and tumor resistance. The exploration of novel treatment approaches, such as combined chemotherapy, holds promise for improving the effectiveness of existing antitumor agents. Cold atmospheric plasma has demonstrated antineoplastic effects in preclinical studies, but its potential in combination with specific ions for lymphosarcoma treatment has not been investigated.

Methods

An in vivo study was conducted using a Pliss lymphosarcoma rat model to evaluate the antitumor effects of composite cold plasma and controlled ionic therapy. Groups of rats were exposed to composite cold plasma for 3, 7, and 14 days, while the control group received no treatment. Additionally, a combination of chemotherapy with cold plasma therapy was assessed, with doxorubicin hydrochloride administered at a dosage of 5 mg/kg. PERENIO IONIC SHIELD™ emitted a controlled ionic formula during the treatment period.

Results

The in vivo study demonstrated tumor growth inhibition in groups exposed to composite cold plasma for 3, 7, and 14 days compared to the control group. Furthermore, combining chemotherapy with cold plasma therapy resulted in a threefold reduction in tumor volume. The most significant antitumor effects were observed when doxorubicin hydrochloride at a dosage of 5 mg/kg was combined with 14 days of PERENIO IONIC SHIELD™ ionic therapy.

Discussion

The use of composite cold plasma therapy, in conjunction with a controlled ionic formula emitted by PERENIO IONIC SHIELD™, in the complex treatment of lymphosarcoma in rats showed promising antitumor effects. The combination therapy, particularly when combined with doxorubicin hydrochloride, demonstrated enhanced efficacy. These findings suggest the potential for utilizing cold atmospheric plasma and controlled ions as an adjunctive treatment approach in lymphosarcoma therapy. Further research is warranted to explore the mechanisms underlying these effects and to evaluate the safety and efficacy in human clinical trials.

Combination effect of cold atmospheric plasma with green synthesized zero-valent iron nanoparticles in the treatment of melanoma cancer model

Green synthesized zero-valent iron nanoparticles (nZVI) have high potential in cancer therapy. Cold atmospheric plasma (CAP) is also an emerging biomedical technique that has great potential to cure cancer. Therefore, the combined effect of CAP and nZVI might be promising in treatment of cancer. In this study, we evaluated the combined effect of CAP and nZVI on the metabolic activity of the surviving cells and induction of apoptosis in malignant melanoma in comparison with normal cells. Therefore, the effect of various time exposure of CAP radiation, different doses of nZVI, and the combined effect of CAP and nZVI were evaluated on the viability of malignant melanoma cells (B16-F10) and normal fibroblast cells (L929) at 24 h after treatment using MTT assay. Then, the effect of appropriate doses of each treatment on apoptosis was evaluated by fluorescence microscopy and flow cytometry with Annexin/PI staining. In addition, the expression of BAX, BCL2 and Caspase 3 (CASP3) was also assayed. The results showed although the combined effect of CAP and nZVI significantly showed cytotoxic effects and apoptotic activity on cancer cells, this treatment had no more effective compared to CAP or nZVI alone. In addition, evaluation of gene expression showed that combination therapy didn't improve expression of apoptotic genes in comparison with CAP or nZVI. In conclusion, combined treatment of CAP and nZVI does not seem to be able to improve the effect of monotherapy of CAP or nZVI. It may be due to the resistance of cancer cells to high ROS uptake or the accumulation of saturated ROS in cells, which prevents the intensification of apoptosis.

Modulation of Inflammatory Responses by a Non-Invasive Physical Plasma Jet during Gingival Wound Healing

Gingival wound healing plays an important role in the treatment of a variety of inflammatory diseases. In some cases, however, wound healing is delayed by various endogenous or exogenous factors. In recent years, non-invasive physical plasma (NIPP), a highly reactive gas, has become the focus of research, because of its anti-inflammatory and wound healing-promoting efficacy. So far, since NIPP application has been poorly elucidated in dentistry, the aim of this study was to further investigate the effect of NIPP on various molecules associated with inflammation and wound healing in gingival cells. Human gingival fibroblasts (HGF) and human gingival keratinocytes (HGK) were treated with NIPP at different application times. Cell viability and cell morphology were assessed using DAPI/phalloidin staining. Cyclooxygenase (COX)2; tumour necrosis factor (TNF); CC Motif Chemokine Ligand (CCL)2; and interleukin (IL)1B, IL6 and IL8 were analysed at the mRNA and protein level by a real-time PCR and ELISA. NIPP did not cause any damage to the cells. Furthermore, NIPP led to a downregulation of proinflammatory molecules. Our study shows that NIPP application does not damage the gingival tissue and that the promotion of wound healing is also due to an anti-inflammatory component.

Cold atmospheric plasma induces apoptosis in human colon and lung cancer cells through modulating mitochondrial pathway

Cold atmospheric plasma (CAP) is an emerging and promising oncotherapy with considerable potential and advantages that traditional treatment modalities lack. The objective of this study was to investigate the effect and mechanism of plasma-inhibited proliferation and plasma-induced apoptosis on human lung cancer and colon cancer cells in vitro and in vivo. Piezobrush® PZ2, a handheld CAP unit based on the piezoelectric direct discharge technology, was used to generate and deliver non-thermal plasma. Firstly, CAPPZ2 treatment inhibited the proliferation of HT29 colorectal cancer cells and A549 lung cancer cells using CCK8 assay, caused morphological changes at the cellular and subcellular levels using transmission electron microscopy, and suppressed both types of tumor cell migration and invasion using the Transwell migration and Matrigel invasion assay. Secondly, we confirmed plasma-induced apoptosis in the HT29 and A549 cells using the AO/EB staining coupled with flow cytometry, and verified the production of apoptosis-related proteins, such as cytochrome c, PARP, cleaved caspase-3 and caspase-9, Bcl-2 and Bax, using western blotting. Finally, the aforementioned in vitro results were tested in vivo using cell-derived xenograft mouse models, and the anticancer effect was confirmed and attributed to CAP-mediated apoptosis. The immunohistochemical analysis revealed that the expression of cleaved caspase-9, caspase-3, PARP and Bax were upregulated whereas that of Bcl-2 downregulated after CAP treatment. These findings collectively suggest that the activation of the mitochondrial pathway is involved during CAPPZ2-induced apoptosis of human colon and lung cancer cells in vitro and in vivo.

Cold Argon Athmospheric Plasma for Biomedicine: Biological Effects, Applications and Possibilities

Currently, plasma medicine is a synthetic direction that unites the efforts of specialists of various profiles. For the successful formation of plasma medicine, it is necessary to solve a large complex of problems, including creating equipment for generating cold plasma, revealing the biological effects of this effect, as well as identifying and justifying the most promising areas of its application. It is known that these biological effects include antibacterial and antiviral activity, the ability to stimulate hemocoagulation, pro-regenerative properties, etc. The possibility of using the factor in tissue engineering and implantology is also shown. Based on this, the purpose of this review was to form a unified understanding of the biological effects and biomedical applications of argon cold plasma. The review shows that cold plasma, like any other physical and chemical factors, has dose dependence, and the variable parameter in this case is the exposure of its application. One of the significant characteristics determining the specificity of the cold plasma effect is the carrier gas selection. This gas carrier is not just an ionized medium but modulates the response of biosystems to it. Finally, the perception of cold plasma by cellular structures can be carried out by activating a special molecular biosensor, the functioning of which significantly depends on the parameters of the medium (in the field of plasma generation and the cell itself). Further research in this area can open up new prospects for the effective use of cold plasma.

Non-Invasive Physical Plasma Generated by a Medical Argon Plasma Device Induces the Expression of Regenerative Factors in Human Gingival Keratinocytes, Fibroblasts, and Tissue Biopsies

After oral surgery, intraoral wound healing and tissue regeneration is an important factor for the success of the entire therapy. In recent years, non-invasive medical plasma (NIPP) has been shown to accelerate wound healing, which would be particularly beneficial for patients with wound healing disorders. Since the application of NIPP in dentistry has not been sufficiently understood, the aim of the present study was to investigate the effect of a medical argon plasma device on gingival cells. Human gingival fibroblasts, keratinocytes, and tissue biopsies were treated with NIPP for different durations. Crucial markers associated with wound healing were examined at the mRNA and protein levels by real-time PCR, ELISA and immunohistochemistry. NIPP treatment led to an increase in Ki67 and MMP1 at mRNA and protein levels. NIPP application lasting longer than 60 s resulted in an increase in apoptotic genes at mRNA level and superficial damage to the epithelium in the tissue biopsies. Overall, our experimental setup demonstrated that NIPP application times of 30 s were most suitable for the treatment of gingival cells and tissue biopsies. Our study provides evidence for potential use of NIPP in dentistry, which would be a promising treatment option for oral surgery.

New Approach against Chondrosoma Cells-Cold Plasma Treatment Inhibits Cell Motility and Metabolism, and Leads to Apoptosis

(1) Background: Chondrosarcoma (CS) is a malignant primary bone tumor with a cartilaginous origin. Its slow cell division and severely restricted vascularization are responsible for its poor responsiveness to chemotherapy and radiotherapy. The decisive factor for the prognosis of CS patients is the only adequate therapy-surgical resection. Cold atmospheric pressure plasma (CAP) is emerging as a new option in anti-cancer therapy. Its effect on chondrosarcomas has been poorly investigated. (2) Methods: Two CS cell lines-SW 1353 and CAL 78-were used. Various assays, such as cell growth kinetics, glucose uptake, and metabolic activity assay, along with two different apoptosis assays were performed after CAP treatment. A radius cell migration assay was used to examine cell motility. (3) Results: Both cell lines showed different growth behavior, which was taken into account when using the assays. After CAP treatment, a reduction in metabolic activity was observed in both cell lines. The immediate effect of CAP showed a reduction in cell numbers and in influence on this cell line's growth rate. The measurement of the glucose concentration in the cell culture medium showed an increase after CAP treatment. Live-dead cell imaging shows an increase in the proportion of dead cells over the incubation time for both cell lines. There was a significant increase in apoptotic signals after 48 h and 72 h for both cell lines in both assays. The migration assay showed that CAP treatment inhibited the motility of chondrosarcoma cells. The effects in all experiments were related to the duration of CAP exposure. (4) Conclusions: The CAP treatment of CS cells inhibits their growth, motility, and metabolism by initiating apoptotic processes.

Lysine Acetylation, Cancer Hallmarks and Emerging Onco-Therapeutic Opportunities

Simple Summary

Several histone deacetylase inhibitors have been approved by FDA for cancer treatment. Intensive efforts have been devoted to enhancing its anti-cancer efficacy by combining it with various other agents. Yet, no guideline is available to assist in the choice of candidate drugs for combination towards optimal solutions for different clinical problems. Thus, it is imperative to characterize the primary cancer hallmarks that lysine acetylation is associated with and gain knowledge on the key cancer features that each combinatorial onco-therapeutic modality targets to aid in the combinatorial onco-therapeutic design. Cold atmospheric plasma represents an emerging anti-cancer modality via manipulating cellular redox level and has been demonstrated to selectively target several cancer hallmarks. This review aims to delineate the intrinsic connections between lysine acetylation and cancer properties, and forecast opportunities histone deacetylase inhibitors may have when combined with cold atmospheric plasma as novel precision onco-therapies.

Abstract

Acetylation, a reversible epigenetic process, is implicated in many critical cellular regulatory systems including transcriptional regulation, protein structure, activity, stability, and localization. Lysine acetylation is the most prevalent and intensively investigated among the diverse acetylation forms. Owing to the intrinsic connections of acetylation with cell metabolism, acetylation has been associated with metabolic disorders including cancers. Yet, relatively little has been reported on the features of acetylation against the cancer hallmarks, even though this knowledge may help identify appropriate therapeutic strategies or combinatorial modalities for the effective treatment and resolution of malignancies. By examining the available data related to the efficacy of lysine acetylation against tumor cells and elaborating the primary cancer hallmarks and the associated mechanisms to target the specific hallmarks, this review identifies the intrinsic connections between lysine acetylation and cancer hallmarks and proposes novel modalities that can be combined with HDAC inhibitors for cancer treatment with higher efficacy and minimum adverse effects.

Plasma bioscience and its application to medicine

Nonthermal atmospheric pressure biocompatible plasma (NBP), alternatively called bio-cold plasma, is a partially ionized gas that consists of charged particles, neutral atoms and molecules, photons, an electric field, and heat. Recently, nonthermal plasma-based technology has been applied to bioscience, medicine, agriculture, food processing, and safety. Various plasma device configurations and electrode layouts has fast-tracked plasma applications in the treatment of biological and material surfaces. The NBP action mechanism may be related to the synergy of plasma constituents, such as ultraviolet radiation or a reactive species. Recently, plasma has been used in the inactivation of viruses and resistant microbes, such as fungal cells, bacteria, spores, and biofilms made by microbes. It has also been used to heal wounds, coagulate blood, degrade pollutants, functionalize material surfaces, kill cancers, and for dental applications. This review provides an outline of NBP devices and their applications in bioscience and medicine. We also discuss the role of plasma-activated liquids in biological applications, such as cancer treatments and agriculture. The individual adaptation of plasma to meet specific medical requirements necessitates real-time monitoring of both the plasma performance and the target that is treated and will provide a new paradigm of plasma-based therapeutic clinical systems.

Cold Atmospheric Plasma: A New Strategy Based Primarily on Oxidative Stress for Osteosarcoma Therapy

Osteosarcoma is the most common primary bone tumor, and its first line of treatment presents a high failure rate. The 5-year survival for children and teenagers with osteosarcoma is 70% (if diagnosed before it has metastasized) or 20% (if spread at the time of diagnosis), stressing the need for novel therapies. Recently, cold atmospheric plasmas (ionized gases consisting of UV-Vis radiation, electromagnetic fields and a great variety of reactive species) and plasma-treated liquids have been shown to have the potential to selectively eliminate cancer cells in different tumors through an oxidative stress-dependent mechanism. In this work, we review the current state of the art in cold plasma therapy for osteosarcoma. Specifically, we emphasize the mechanisms unveiled thus far regarding the action of plasmas on osteosarcoma. Finally, we review current and potential future approaches, emphasizing the most critical challenges for the development of osteosarcoma therapies based on this emerging technique.

Cold atmospheric plasma induced genotoxicity and cytotoxicity in esophageal cancer cells

In this paper, we studied the functional effects of cold atmospheric plasma (CAP) on the esophageal cancer cell line (KYSE-30) by direct and indirect treatment and fibroblast cell lines as normal cells. KYSE-30 cells were treated with CAP at different time points of 60, 90, 120 and, 240 s for direct exposure and 90, 180, 240 and, 360 s for indirect exposure. Cell viability was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and apoptosis induction in the treated cells was measured by Annexin-V/PI using flow cytometry. The expression of apoptotic related genes (BAX/BCL-2) was analyzed by real-time polymerase chain reaction. Moreover, the genotoxicity was analyzed by comet assay. Cell viability results showed that direct CAP treatment has a markedly cytotoxic impact on the reduction of KYSE-30 cells at 60 s (p = 0.000), while indirect exposure was less impactful (p > 0.05). The results of the Annexin-V/PI staining confirmed this analysis. Subsequently, the genotoxicity study of the direct CAP treatment demonstrated a longer tail-DNA length and caused increase in DNA damage in the cells (p < 0.00001) as well as shift BAX/BCL-2 toward apoptosis. The concentration of H₂O₂ and NO₂^- in direct CAP treatment was significantly higher than indirect (p > 0.05). Treatment with direct CAP showed genotoxicity in cancer cells. Collectively, our results pave a deeper understanding of CAP functions and the way for further investigations in the field of esophageal cancer treatment.

Inhibition of Angiogenesis by Treatment with Cold Atmospheric Plasma as a Promising Therapeutic Approach in Oncology

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.

Utility of Reactive Species Generation in Plasma Medicine for Neuronal Development

Reactive oxygen species (ROS) are critical signaling molecules for neuronal physiology that stimulate growth and development and play vital roles in several pathways when in a balanced state, but they cause neurodegeneration when unbalanced. As ROS levels above a certain threshold cause the activation of the autophagy system, moderate levels of ROS can be used as treatment strategies. Currently, such treatments are used together with low-level laser or photodynamic therapies, photo-bio modulation, or infrared treatments, in different chronic diseases but not in the treatment of neurodegeneration. Recently, non-thermal plasma has been successfully used in biomedical applications and treatments, and beneficial effects such as differentiation, cell growth, and proliferation, stimulation of ROS based pathways have been observed. Besides the activation of a wide range of biological signaling pathways by generating ROS, plasma application can be an effective treatment in neuronal regeneration, as well as in neuronal diseases. In this review, we summarize the generation and role of ROS in neurons and provide critical insights into their potential benefits on neurons. We also discuss the underlying mechanisms of ROS on neuronal development. Regarding clinical applications, we focus on ROS-based neuronal growth and regeneration strategies and in the usage of non-thermal plasma in neuronal and CNS injury treatments.

Anticancer Effects of Cold Atmospheric Plasma in Canine Osteosarcoma Cells

Osteosarcoma is known to be one of the frequently occurring cancers in dogs. Its prognosis is usually very poor, with a high incidence of lung metastasis. Although radiation therapy has become a major therapeutic choice for canine osteosarcoma, the high costs and unexpected side effects prevent some patients from considering this treatment. Cold atmospheric plasma (CAP) is an ionized gas with high energy at low temperatures, and it produces reactive oxygen species that mediate many signaling pathways. Although many researchers have used CAP as an anticancer therapeutic approach in humans, its importance has been neglected in veterinary medicine. In this study, D-17 and DSN canine osteosarcoma cell lines were treated with CAP to observe its anticancer activity. By high-content screening and flow cytometry, CAP-treated cells showed growth arrest and apoptosis induction. Moreover, the osteosarcoma cells exhibited reduced migration and invasion activity when treated with CAP. Overall, CAP exerted an anticancer effect on canine osteosarcoma cell lines. CAP may have the potential to be used as a novel modality for treating cancer in veterinary medicine.

An Innovative Therapeutic Option for the Treatment of Skeletal Sarcomas: Elimination of Osteo- and Ewing's Sarcoma Cells Using Physical Gas Plasma

Osteosarcoma and Ewing’s sarcoma are the most common malignant bone tumors. Conventional therapies such as polychemotherapy, local surgery, and radiotherapy improve the clinical outcome for patients. However, they are accompanied by acute and chronic side effects that affect the quality of life of patients, motivating novel research lines on therapeutic options for the treatment of sarcomas. Previous experimental work with physical plasma operated at body temperature (cold atmospheric plasma, CAP) demonstrated anti-oncogenic effects on different cancer cell types. This study investigated the anti-cancer effect of CAP on two bone sarcoma entities, osteosarcoma and Ewing’s sarcoma, which were represented by four cell lines (U2-OS, MNNG/HOS, A673, and RD-ES). A time-dependent anti-proliferative effect of CAP on all cell lines was observed. CAP-induced alterations in cell membrane functionality were detected by performing a fluorescein diacetate (FDA) release assay and an ATP release assay. Additionally, modifications of the cell membrane and modifications in the actin cytoskeleton composition were examined using fluorescence microscopy monitoring dextran-uptake assay and G-/F-actin distribution. Furthermore, the CAP-induced induction of apoptosis was determined by TUNEL and active caspases assays. The observations suggest that a single CAP treatment of bone sarcoma cells may have significant anti-oncogenic effects and thus may be a promising extension to existing applications.

Cold Atmospheric Plasma Treatment of Chondrosarcoma Cells Affects Proliferation and Cell Membrane Permeability

Chondrosarcoma is the second most common malign bone tumor in adults. Surgical resection of the tumor is recommended because of its resistance to clinical treatment such as chemotherapy and radiation therapy. Thus, the prognosis for patients mainly depends on sufficient surgical resection. Due to this, research on alternative therapies is needed. Cold atmospheric plasma (CAP) is an ionized gas that contains various reactive species. Previous studies have shown an anti-oncogenic potential of CAP on different cancer cell types. The current study examined the effects of treatment with CAP on two chondrosarcoma cell lines (CAL-78, SW1353). Through proliferation assay, the cell growth after CAP-treatment was determined. A strong antiproliferative effect for both cell lines was detected. By fluorescein diacetate (FDA) assay and ATP release assay, alterations in the cell membrane and associated translocation of low molecular weight particles through the cytoplasmic membrane were observed. In supernatant, the non-membrane-permeable FDA and endogenously synthesized ATP detected suggest an increased membrane permeability after CAP treatment. Similar results were shown by the dextran-uptake assay. Furthermore, fluorescence microscopic G-/F-actin assay was performed. G- and F-actin were selectively dyed, and the ratio was measured. The presented results indicate CAP-induced changes in cell membrane function and possible alterations in actin-cytoskeleton, which may contribute to the antiproliferative effects of CAP.