Comparative Effects of Non-Thermal Atmospheric Pressure Plasma on Migration and Invasion in Oral Squamous Cell Cancer, by Gas Type

PURPOSE: The fourth state of matter, plasma is known as an ionized gas with electrons, radicals and ions. The use of non-thermal plasma (NTP) in cancer research became possible because of the progresses in plasma medicine. Previous studies on the potential NTP-mediated cancer therapy have mainly concentrated on cancer cell apoptosis. In the present study, we compared the inhibitory effect of NTP on cell migration and invasion in the oral squamous cancer cell lines. MATERIALS AND METHODS: We used oral squamous cancer cell lines (SCC1483, MSKQLL1) and different gases (N₂, He, and Ar). To investigate the mechanism of plasma treatment, using different gases (N₂, He, and Ar) which induces anti-migration and anti-invasion properties, we performed wound healing assay, invasion assay and gelatin zymography. RESULTS: The results showed that NTP inhibits cancer cell migration and invasion of oral squamous cancer cell. In addition, focal adhesion kinase expression and matrix metalloproteinase-2/9 activity were also inhibited. CONCLUSION: The suppression of cancer cell invasion by NTP varied depending on the type of gas. Comparison of the three gases revealed that N₂ NTP inhibited cell migration and invasion most potently via decreased expression of focal adhesion kinase and matrix metalloproteinase activity.

Nonthermal Plasma Induces Apoptosis in ATC Cells: Involvement of JNK and p38 MAPK-Dependent ROS

PURPOSE: To determine the effects of nonthermal plasma (NTP) induced by helium (He) alone or He plus oxygen (O2) on the generation of reactive oxygen species (ROS) and cell death in anaplastic thyroid cancer cells. MATERIALS AND METHODS: NTP was generated in He alone or He plus O2 blowing through a nozzle by applying a high alternating current voltage to the discharge electrodes. Optical emission spectroscopy was used to identify various excited plasma species. The apoptotic effect of NTP on the anaplastic thyroid cancer cell lines, such as HTH83, U-HTH 7, and SW1763, was verified with annexin V/propidium staining and TUNEL assay. ROS formation after NTP treatment was identified with fluorescence-activated cell sorting with DCFDA staining. The mitogen-activated protein kinase pathways and caspase cascade were investigated to evaluate the molecular mechanism involved and cellular targets of plasma. RESULTS: NTP induced significant apoptosis in all three cancer cell lines. The plasma using He and O2 generated more O2-related species, and increased apoptosis and intracellular ROS formation compared with the plasma using He alone. NTP treatment of SW1763 increased the expression of phosphor-JNK, phosphor-p38, and caspase-3, but not phosphor-ERK. Apoptosis of SW1763 as well as expressions of elevated phosphor-JNK, phosphor-p38, and caspase-3 induced by NTP were effectively inhibited by intracellular ROS scavengers. CONCLUSION: NTP using He plus O2 induced significant apoptosis in anaplastic cancer cell lines through intracellular ROS formation. This may represent a new promising treatment modality for this highly lethal disease.

Assignments of the tyrosinase related protein-1 and -2 genes to human chromosome bands 9p23 and 13q32.1 by in situ hybridization

To determine the precise chromosomal localization of tyrosine related protein-1 and -2 (TRP-1 and TRP-2) genes by fluorescence in situ hybridization, we used DNAs isolated from human bacterial artificial chromosome clones. They contain genomic sequences with approximately 120 kb inserts for TRP-1 and TRP-2. The TRP-1 and TRP-2 genes were assigned to human chromosome bands 9p23 and 13q32.1, respectively. These results confirmed the previously mapped location for the TRP-1 gene and more precisely located the TRP-2 gene, which had previously been mapped to chromosome 13q31-q32.