Non-thermal atmospheric pressure plasma has been widely used for preclinical studies in areas such as wound healing, blood coagulation, and cancer therapy. We previously developed plasma-activated medium (PAM) and plasma-activated Ringer’s lactate solutions (PAL) for cancer treatments. Many in vitro and in vivo experiments demonstrated that both PAM and PAL exhibit anti-tumor effects in several types of cancer cells such as ovarian, gastric, and pancreatic cancer cells as well as glioblastoma cells. However, interestingly, PAM induces more intracellular reactive oxygen species in glioblastoma cells than PAL. To investigate the differences in intracellular molecular mechanisms of the effects of PAM and PAL in glioblastoma cells, we measured gene expression levels of antioxidant genes such as CAT, SOD2, and GPX1. Microarray and quantitative real-time PCR analyses revealed that PAM elevated stress-inducible genes that induce apoptosis such as GADD45α signaling molecules. PAL suppressed genes downstream of the survival and proliferation signaling network such as YAP/TEAD signaling molecules. These data reveal that PAM and PAL induce apoptosis in glioblastoma cells by different intracellular molecular mechanisms.

Ovarian cancer is a highly invasive and metastatic disease with a poor prognosis if diagnosed at an advanced stage, which is often the case. Recent studies argue that ovarian cancer cells that have undergone epithelial-to-mesenchymal transition (EMT) acquire aggressive malignant properties, but the relevant molecular mechanisms in this setting are not well-understood. Here, we report findings from an siRNA screen that identified the homeobox transcription factor ALX1 as a novel regulator of EMT. RNA interference–mediated attenuation of ALX1 expression restored E-cadherin expression and cell–cell junction formation in ovarian cancer cells, suppressing cell invasion, anchorage-independent growth, and tumor formation. Conversely, enforced expression of ALX1 in ovarian cancer cells or nontumorigenic epithelial cells induced EMT. We found that ALX1 upregulated expression of the key EMT regulator Snail (SNAI1) and that it mediated EMT activation and cell invasion by ALX1. Our results define the ALX1/Snail axis as a novel EMT pathway that mediates cancer invasion. Cancer Res; 73(5); 1581–90. ©2012 AACR.

The biological function of non-thermal atmospheric pressure plasma has been widely accepted in several types of cancer. We previously developed plasma-activated medium (PAM) for clinical use, and demonstrated that PAM exhibits a metastasis-inhibitory effect on ovarian cancer through reduced MMP-9 secretion. However, the anti-tumor effects of PAM on endometrial cancer remain unknown. In this study, we investigated the inhibitory effect of PAM on endometrial cancer cell viability in vitro. Our results demonstrated that AMEC and HEC50 cell viabilities were reduced by PAM at a certain PAM ratio, and PAM treatment effectively increased autophagic cell death in a concentration dependent manner. In addition, we evaluated the molecular mechanism of PAM activity and found that the mTOR pathway was inactivated by PAM. Moreover, our results demonstrated that the autophagy inhibitor MHY1485 partially inhibited the autophagic cell death induced by PAM treatment. These findings indicate that PAM decreases the viability of endometrial cancer cells along with alteration of the mTOR pathway, which is critical for cancer cell viability. Collectively, our data suggest that PAM inhibits cell viability while inducing autophagic cell death in endometrial cancer cells, representing a potential novel treatment for endometrial cancer.