Non-equilibrium atmospheric pressure plasmas generate a high electron density (on the order of 1016 electrons per cm−3) using Ar gas. Culture medium in air at room temperature was plasma-irradiated ...for several hundred seconds. Tens of micromolar hydrogen peroxide (H2O2) and millimolar levels of nitrous ion (NO2−) were detected in the plasma-irradiated culture medium (plasma activated medium; PAM) and selectively induced the apoptotic death of glioblastoma tumor cells, but did not kill normal mammary epithelial cells. A similar antitumor effect was induced by spiking the medium with comparable concentrations of H2O2 and NO2−. The PAM remained still a somewhat difference that it should also be assessed for understanding other latent mechanisms.
Display omitted
•Induction by PAM of apoptosis in glioblastoma but not in normal epithelial cells.•Quantitative analysis of H2O2 and NO2− concentrations in PAM.•Cancer kill by H2O2 and NO2− in non-treated medium at concentrations same as PAM.•Evidence of a synergism of H2O2 and NO2− on selective kill upon incubation in PAM.•The antitumor effect of PAM is not due solely to the synergism of H2O2 and NO2−.
Epithelial ovarian cancer (EOC) is considered to secrete various factors in order to promote peritoneal dissemination through cell-to-cell interaction between cancer and mesothelial cells. We ...previously revealed that TGF-β secreted from EOC induces normal human peritoneal mesothelial cells (HPMCs) to differentiate into cancer-associated mesothelial cells (CAMCs). However, the relationship between tumor cells and CAMCs in EOC is still unclear. We hypothesized that CAMCs also secrete chemokines that attract cancer cells and induce peritoneal dissemination of EOC. We examined chemokines secreted from HPMCs and CAMCs by human chemokine array, and revealed that conditioned medium of CAMCs (CAMCs-CM) included many types of chemokines. The signals of CCL2 were the highest compared with other chemokines. The secretion and relative expression of CCL2 were significantly higher in CAMCs. Recombinant CCL2 promoted trans-mesothelial migration of HPMCs and the migration and invasion by EOC cells. In addition, CCL2 secreted from CAMCs promoted invasion of EOC cells. Furthermore, the neutralizing antibody of CCL2 reduced invasion by EOC. Clinical outcomes of patients whose tissue expressed higher CCR2 were significantly poorer than in patients whose tissue expression was lower. CCL2 activated the phosphorylation of p38 mitogen-activated protein kinase (MAPK). In addition, CAMCs-CM activated the p38 MAPK pathway. Phosphorylation of p38 MAPK reduced with the presence of neutralizing antibody of CCL2. In conclusion, these data indicate CCL2 in CAMCs-CM promoted the malignant potential of EOC. CCL2 plays a crucial role in the tumor microenvironment of EOC.
Nonequilibrium atmospheric pressure plasma (NEAPP) therapy has recently been focused on as a novel medical practice. Using cells with acquired paclitaxel/cisplatin resistance, we elucidated effects ...of indirect NEAPP-activated medium (NEAPP-AM) exposure on cell viability and tumor growth in vitro and in vivo.
Using chronic paclitaxel/cisplatin-resistant ovarian cancer cells, we applied indirect NEAPP-exposed medium to cells and xenografted tumors in a mouse model. Furthermore, we examined the role of reactive oxygen species (ROS) or their scavengers in the above-mentioned EOC cells.
We assessed the viability of NOS2 and NOS3 cells exposed to NEAPP-AM, which was prepared beforehand by irradiation with NEAPP for the indicated time. In NOS2 cells, viability decreased by approximately 30% after NEAPP-AM 120-sec treatment (P<0.01). The growth-inhibitory effects of NEAPP-AM were completely inhibited by N-acetyl cysteine treatment, while L-buthionine-S, R-sulfoximine, an inhibitor of the ROS scavenger used with NEAPP-AM, decreased cell viability by 85% after NEAPP-AM 60-sec treatment(P<0.05) and by 52% after 120 sec, compared to the control (P<0.01). In the murine subcutaneous tumor-formation model, NEAPP-AM injection resulted in an average inhibition of the NOS2 cell-inoculated tumor by 66% (P<0.05) and NOS2TR cell-inoculated tumor by 52% (P<0.05), as compared with the control.
We demonstrated that plasma-activated medium also had an anti-tumor effect on chemo-resistant cells in vitro and in vivo. Indirect plasma therapy is a promising treatment option for EOC and may contribute to a better patient prognosis in the future.
Non-thermal atmospheric pressure plasma is a novel approach for wound healing, blood coagulation, and cancer therapy. A recent discovery in the field of plasma medicine is that non-thermal ...atmospheric pressure plasma not only directly but also indirectly affects cells via plasma-treated liquids. This discovery has led to the use of non-thermal atmospheric pressure plasma as a novel chemotherapy. We refer to these plasma-treated liquids as plasma-activated liquids. We chose Ringer's solutions to produce plasma-activated liquids for clinical applications. In vitro and in vivo experiments demonstrated that plasma-activated Ringer's lactate solution has anti-tumor effects, but of the four components in Ringer's lactate solution, only lactate exhibited anti-tumor effects through activation by non-thermal plasma. Nuclear magnetic resonance analyses indicate that plasma irradiation generates acetyl and pyruvic acid-like groups in Ringer's lactate solution. Overall, these results suggest that plasma-activated Ringer's lactate solution is promising for chemotherapy.
Advanced ovarian cancers are highly metastatic due to frequent peritoneal dissemination, resulting in dismal prognosis. Here we report the functions of cancer-derived extracellular vesicles (EVs), ...which are emerging as important mediators of tumour metastasis. The EVs from highly metastatic cells strongly induce metastatic behaviour in moderately metastatic tumours. Notably, the cancer EVs efficiently induce apoptotic cell death in human mesothelial cells in vitro and in vivo, thus resulting in the destruction of the peritoneal mesothelium barrier. Whole transcriptome analysis shows that MMP1 is significantly elevated in mesothelial cells treated with highly metastatic cancer EVs and intact MMP1 mRNAs are selectively packaged in the EVs. Importantly, MMP1 expression in ovarian cancer is tightly correlated with a poor prognosis. Moreover, MMP1 mRNA-carrying EVs exist in the ascites of cancer patients and these EVs also induce apoptosis in mesothelial cells. Our findings elucidate a previously unknown mechanism of peritoneal dissemination via EVs.
MicroRNAs (miRNAs) regulate the expression of their target genes post-transcriptionally; thus, they are deeply involved in fundamental biological processes. miRNA clusters contain two or more ...miRNA-encoding genes, and these miRNAs are usually coexpressed due to common expression mechanisms. Therefore, miRNA clusters are effective modulators of biological pathways by the members coordinately regulating their multiple target genes, and an miRNA cluster located on the X chromosome q27.3 region has received much attention in cancer research recently. In this review, we discuss the novel findings of the chrXq27.3 miRNA cluster in various types of cancer.The chrXq27.3 miRNA cluster contains 30 mature miRNAs synthesized from 22 miRNA-encoding genes in an ~ 1.3-Mb region. The expressions of these miRNAs are usually negligible in many normal tissues, with the male reproductive system being an exception. In cancer tissues, each miRNA is dysregulated, compared with in adjacent normal tissues. The miRNA-encoding genes are not uniformly distributed in the region, and they are further divided into two groups (the miR-506-514 and miR-888-892 groups) according to their location on the genome. Most of the miRNAs in the former group are tumor-suppressive miRNAs that are further downregulated in various cancers compared with normal tissues. miR-506-3p in particular is the most well-known miRNA in this cluster, and it has various tumor-suppressive functions associated with the epithelial-mesenchymal transition, proliferation, and drug resistance. Moreover, other miRNAs, such as miR-508-3p and miR-509-3p, have similar tumor-suppressive effects. Hence, the expression of these miRNAs is clinically favorable as prognostic factors in various cancers. However, the functions of the latter group are less understood. In the latter group, miR-888-5p displays oncogenic functions, whereas miR-892b is tumor suppressive. Therefore, the functions of the miR-888-892 group are considered to be cell type- or tissue-specific.In conclusion, the chrXq27.3 miRNA cluster is a critical regulator of cancer progression, and the miRNAs themselves, their regulatory mechanisms, and their target genes might be promising therapeutic targets.
Cancer therapy consists of multidisciplinary treatment combining surgery, chemotherapy, radiotherapy, and immunotherapy. Despite the elucidation of cancer mechanisms by comprehensive genomic and ...epigenomic analyses and the development of molecular therapy, drug resistance and severe side effects have presented challenges to the long-awaited development of new therapies. With the rapid technological advances in the last decade, there are now reports concerning potential applications of non-equilibrium atmospheric pressure plasma (NEAPP) in cancer therapy. Two approaches have been tried: direct irradiation with NEAPP (direct plasma) and the administration of a liquid (e.g. culture medium, saline, Ringer's lactate) activated by NEAPP (plasma-activated solutions: PAS). Direct plasma is a unique treatment method in which various active species, charged ions, and photons are delivered to the affected area, but the direct plasma approach has physical limitations related to the device used, such as a limited depth of reach and limited irradiation area. PAS is a liquid that contains reactive oxygen species generated by PAS, and it has been confirmed to have antitumor activity that functions in the same manner as direct plasma. This review introduces recent studies of PAS and informs researchers about the potential of PAS for cancer therapy.
Potential applications of plasma-activated solutions (PAS) in cancer therapy are described.
Plasma-activated species generated in PAS, its effect on tumor cells, contribution to nonmalignant immune cells, selectivity and safety are presented.
The proposed anti-tumor mechanisms of PAS to date are described.
Efficacy and safety evaluations of PAS have been studied in experimental animal models, but no human studies have been conducted.
Chemotherapy is one of the important and effective options for cancer treatment in the past decades. Although the response rate of initial chemotherapy is considerably high in certain types of ...cancers, such as ovarian cancer and lung cancer, the patients frequently suffer from chemoresistance and recurrence of disease. Recent genome-wide studies have shown that the large number of long non-coding RNAs (lncRNAs) are transcribed from the human genome and involved in many biological processes including carcinogenesis. They aberrantly regulate variety of cell functions, such as cell cycle, apoptosis, autophagy, and metabolisms, which are associated with chemosensitivity. Therefore, understanding the biological and clinical impacts of lncRNAs on tumor behavior and its potential as a predictive biomarker for chemotherapy effectiveness is highly desired. In this review, we classify the major mechanisms of lncRNA-related chemoresistance and provide theoretical evidences for targeting lncRNAs in certain types of cancers that may open up new therapeutic paradigm for cancer treatment.
Non-thermal atmospheric pressure plasma has been proposed as a new therapeutic tool for cancer treatment. Recently, plasma-activated medium (PAM) has been widely studied in various cancer types. ...However, there are only few reports demonstrating the anti-tumour effects of PAM in an animal model reflecting pathological conditions and the accompanying mechanism. Here we investigated the inhibitory effect of PAM on the metastasis of ovarian cancer ES2 cells in vitro and in vivo. We demonstrated that ES2 cell migration, invasion and adhesion were suppressed by PAM at a certain PAM dilution ratio, whereas cell viability remained unaffected. In an in vivo mouse model of intraperitoneal metastasis, PAM inhibited peritoneal dissemination of ES2 cells, resulting in prolonged survival. Moreover, we assessed the molecular mechanism and found that MMP-9 was decreased by PAM. On further investigation, we also found that PAM prevented the activation of the MAPK pathway by inhibiting the phosphorylation of JNK1/2 and p38 MAPK. These findings indicate that PAM inhibits the metastasis of ovarian cancer cells through reduction of MMP-9 secretion, which is critical for cancer cell motility. Our findings suggest that PAM intraperitoneal therapy may be a promising treatment option for ovarian cancer.
Low-temperature plasma is being widely used in the various fields of life science, such as medicine and agriculture. Plasma-activated solutions have been proposed as potential cancer therapeutic ...reagents. We previously reported that plasma-activated Ringer's lactate solution exhibited selective cancer-killing effects, and that the plasma-treated L-sodium lactate in the solution was an anti-tumor factor; however, the components that are generated through the interactions between plasma and L-sodium lactate and the components responsible for the selective killing of cancer cells remain unidentified. In this study, we quantified several major chemical products, such as pyruvate, formate, and acetate, in plasma-activated L-sodium lactate solution by nuclear magnetic resonance analysis. We further identified novel chemical products, such as glyoxylate and 2,3-dimethyltartrate, in the solution by direct infusion-electrospray ionization with tandem mass spectrometry analysis. We found that 2,3-dimethyltartrate exhibited cytotoxic effects in glioblastoma cells, but not in normal astrocytes. These findings shed light on the identities of the components that are responsible for the selective cytotoxic effect of plasma-activated solutions on cancer cells, and provide useful data for the potential development of cancer treatments using plasma-activated L-sodium lactate solution.
PDF
