title: Effectiveness of plasma treatment on gastric cancer cells.
abstract: BACKGROUND
  Treatment of peritoneal carcinomatosis arising from gastric cancer remains a considerable challenge. In recent years, the anticancer effect of nonequilibrium atmospheric pressure plasma (NEAPP) has been reported in several cancer cell lines. Use of NEAPP may develop into a new class of anticancer therapy that augments surgery, chemotherapy, and radiotherapy.
  
  
  METHODS
  Gastric cancer cells were assessed for changes in cell morphology and rate of proliferation after treatment with NEAPP-exposed medium (PAM). To explore the functional mechanism, caspase 3/7, annexin V, and uptake of reactive oxygen species (ROS) were evaluated, along with the effect of the ROS scavenger N-acetylcysteine (NAC).
  
  
  RESULTS
  PAM treatment for 24 h affected cell morphology, suggestive of induction of apoptosis. PAM cytotoxicity was influenced by the time of exposure to PAM, the type of cell line, and the number of cells seeded. Cells treated with PAM for 2 h demonstrated activated caspase 3/7 and an increased proportion of annexin V-positive cells compared with untreated cells. Additionally, ROS uptake was observed in PAM-treated cells, whereas NAC reduced the cytotoxicity induced by PAM presumably through reduction of ROS uptake. Furthermore, CD44 variant 9, which reportedly leads to glutathione synthesis and suppresses stress signaling of ROS, was overexpressed in PAM-resistant cells.
  
  
  CONCLUSIONS
  PAM treatment induced apoptosis of gastric cancer cells through generation and uptake of ROS. Local administration of PAM could develop into an option to treat peritoneal carcinomatosis.
authors.affiliation: Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Torii
authors.forename: Suguru
authors.initials: S
authors.lastname: Yamada
authors.forename: Kae
authors.initials: K
authors.lastname: Nakamura
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Tanaka
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kajiyama
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Tanahashi
authors.forename: Naoki
authors.initials: N
authors.lastname: Iwata
authors.forename: Mitsuro
authors.initials: M
authors.lastname: Kanda
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kobayashi
authors.forename: Chie
authors.initials: C
authors.lastname: Tanaka
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Fujii
authors.forename: Goro
authors.initials: G
authors.lastname: Nakayama
authors.forename: Masahiko
authors.initials: M
authors.lastname: Koike
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sugimoto
authors.forename: Shuji
authors.initials: S
authors.lastname: Nomoto
authors.forename: Atsushi
authors.initials: A
authors.lastname: Natsume
authors.forename: Michitaka
authors.initials: M
authors.lastname: Fujiwara
authors.forename: Masaaki
authors.initials: M
authors.lastname: Mizuno
authors.forename: Masaru
authors.initials: M
authors.lastname: Hori
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Saya
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kodera
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000187:drug effects; D001274:Atmospheric Pressure; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics; D008875:Middle Aged; D058626:Plasma Gases / Q000627:therapeutic use*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013274:Stomach Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000628:therapy*
chemical_list: C448906:CD44v9 antigen; D018960:Hyaluronan Receptors; D058626:Plasma Gases; D017382:Reactive Oxygen Species; D000111:Acetylcysteine