One of the promising possibilities of the clinical application of cold plasma, so-called cold atmospheric plasma (CAP), is its application on malignant cells and cancer tissue using its anti-neoplastic effects, primarily through the delivery of reactive oxygen and nitrogen species (ROS, RNS). In this study, we investigated the impact of CAP on cellular proliferation and consecutive molecular response mechanisms in established prostate cancer (PC) cell lines. PC cells showed a significantly reduced cell growth following CAP treatment as a result of both an immediate increase of intracellular peroxide levels and through the induction of apoptosis indicated by annexin V assay, TUNEL assay, and the evaluation of changes in nuclear morphology. Notably, co-administration of N-acetylcysteine (NAC) completely neutralized CAP effects by NAC uptake and rapid conversion to glutathione (GSH). Vitamin C could not counteract the CAP induced effects on cell growth. In summary, relatively short treatments with CAP of 10 seconds were sufficient to induce a significant inhibition of cancer proliferation, as observed for the first time in urogenital cancer. Therefore, it is important to understand the mode of CAP related cell death and clarify and optimize CAP as cancer therapy. Increased levels of peroxides can alter redox-regulated signaling pathways and can lead to growth arrest and apoptosis. We assume that the general intracellular redox homeostasis, especially the levels of cellular GSH and peroxidases such as peroxiredoxins affect the outcome of the CAP treatment.

Background: Apoptosis results in specific and stage-dependent morphological alterations of the cell nucleus, including pyknosis and cell shrinking. The experimental investigation of apoptotic processes is still challenging and routinely based on the assessment of molecular events like chromatin fragmentation and caspase enzyme activity. Alternatively, the establishment of a fluorescence microscopy nuclear morphology assay would provide a simple and robust low-cost method for detection and quantification of apoptotic cascades. Materials and Methods: Model cell lines LNCaP and MDA-MB-231 were incubated in the presence of the apoptosis-inducer cycloheximide (CHX). After evaluation of apoptotic cascades by terminal deoxynucleotidyl transferase-dUTP nick-end labeling (TUNEL) assay, stained cell nuclei were analyzed regarding area, perimeter, major and minor axis, as well as brightness of nuclear fluorescence signal. Results: When compared to vehicle-treated control cells, administration of CHX led to significantly reduced cell growth and elevated rates of chromatin fragmentation of both cell lines as shown by cell counting and TUNEL assay, respectively. These apoptotic effects were accompanied by apoptosis-specific modulations of the nuclei demonstrated by diminished nuclear morphology parameters, such as area, perimeter, major and minor axis, as well as elevated levels of nuclear staining intensity. Conclusion: We present a computerized method for apoptosis detection and quantification using images of fluorescent dye-stained cell nuclei. The advantages of this nuclear morphology assay include the (i) ability to routinely assess apoptosis by a fast, highly reproducible low-cost technique, (ii) applicability of an experimental approach analyzing high numbers of single nuclei and (iii) detection of apoptosis in early, as well as late, stages of the apoptotic cascade.

Phosphorylated histone 2AX (γH2AX) is a long-standing marker for DNA double-strand breaks (DSBs) from ionizing radiation in the field of radiobiology. This led to the perception ofγH2AX being a general marker of direct DNA damage with the treatment of other agents such as low-dose exogenous ROS that unlikely act on cellular DNA directly. Cold physical plasma confers biomedical effects majorly via release of reactive oxygen and nitrogen species (ROS).In vitro, increase ofγH2AX has often been observed with plasma treatment, leading to the conclusion that DNA damage is a direct consequence of plasma exposure. However, increase inγH2AX also occurs during apoptosis, which is often observed with plasma treatment as well. Moreover, it must be questioned if plasma-derived ROS can reach into the nucleus and still be reactive enough to damage DNA directly. We investigatedγH2AX induction in a lymphocyte cell line upon ROS exposure (plasma, hydrogen peroxide, or hypochlorous acid) or UV-B light. Cytotoxicity andγH2AX induction was abrogated by the use of antioxidants with all types of ROS treatment but not UV radiation. H2AX phosphorylation levels were overall independent of analyzing either all nucleated cells or segmentingγH2AX phosphorylation for each cell cycle phase. SB202190 (p38-MAPK inhibitor) and Z-VAD-FMK (pan-caspase inhibitor) significantly inhibitedγH2AX induction upon ROS but not UV treatment. Finally, and despiteγH2AX induction, UV but not plasma treatment led to significantly increased micronucleus formation, which is a functional read-out of genotoxic DNA DSBs. We conclude that plasma-mediated and low-ROSγH2AX induction depends on caspase activation and hence is not the cause but consequence of apoptosis induction. Moreover, we could not identify lasting mutagenic effects with plasma treatment despite phosphorylation of H2AX.

Background/Aim: Ovarian cancer (OC) is a gynecologic tumor with poor prognosis. Despite radical cytoreductive surgery and platinum-based adjuvant systemic treatment, OC will relapse in the majority of the cases. Thus, cold atmospheric plasma (CAP), a highly reactive physical state bearing diverse biological activities being suited for anticancer therapy, may be a promising option in OC therapy. Materials and Methods: OC cell lines were exposed either directly to the CAP or to cell culture medium previously exposed to CAP. Cell proliferation and cell motility was measured. Results: The data demonstrated, that even a single application of a short-term CAP treatment led to an attenuation of OC cell growth and motility. Moreover, incubation with CAP-treated cell culture medium gave similar effects. Results were consistent in four OC cell lines. Conclusion: In summary, the CAP application in oncological surgery leads to strong anti-proliferative effects and opens up novel opportunities for the OC treatment.

(1) Background: Cervical intraepithelial neoplasia (CIN) of long-term persistence or associated with individual treatment indications often requires highly invasive treatments. These are associated with risks of bleeding, infertility, and pregnancy complications. For low- and middle-income countries (LMICs), standard treatment procedures are difficult to implement and manage. We characterized the application of the highly energized gas “noninvasive physical plasma” (NIPP) for tissue devitalization and the treatment of CIN. (2) Methods: We report the establishment of a promising tissue devitalization procedure by NIPP application. The procedure was characterized at the in vitro, ex vivo and in vivo levels. We performed the first prospective, single-armed phase-IIb trial in 20 CIN1/2 patients (NCT03218436). (3) Results: NIPP-treated cervical cancer cells used as dysplastic in vitro model exhibited significant cell growth retardation due to DNA damage, cell cycle arrest and apoptosis. Ex vivo and in vivo tissue assessments showed a highly noninvasive and tissue-preserving treatment procedure which induces transmucosal tissue devitalization. Twenty participants were treated with NIPP and attended a 24-week follow-up. Treatment success was achieved in 19 (95%) participants without postinterventional complications other than mild to moderate discomfort during application. (4) Conclusions: The results from this study preliminarily suggest that NIPP could be used for an effective and tissue-preserving treatment for CIN without the disadvantages of standard treatments. However, randomized controlled trials must confirm the efficacy and noninferiority of NIPP compared to standard treatments.