title: Extracellular signal-regulated kinase phosphorylation due to menadione-induced arylation mediates growth inhibition of pancreas cancer cells.
abstract: BACKGROUND
  Cytotoxicity of Vitamin K3 (VK3) is indicated to have the same mechanism with oxidative stress (H(2)O(2)). In the present study, we analyzed the differences and/or similarities in the cellular responses to oxidative stress and VK3 to clarify the mechanism of growth inhibition.
  
  
  METHODS
  Cell viability was determined by a test method with 3-[4, 5-dimethyl-thiazol]-2, 5-dephenyl tetrazolium bromide (MTT). Expressions of cellular proteins were evaluated by Western blot analysis.
  
  
  RESULTS
  The IC50 was calculated to be 47.3 +/- 4.1 microM for VK3 and 2.2 +/- 1.2 microM for H(2)O(2). By Western blot analysis, VK3 or H(2)O(2) was shown to induce rapid phosphorylation of extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinases (JNKs). H(2)O(2)-induced phosphorylation of ERK and JNK was almost complete inhibited by more than 100-muM genistein. VK3-induced JNK phosphorylation was blocked by 100-microM genistein, but ERK phosphorylation was not inhibited completely even if 400-microM genistein was used. H(2)O(2)-induced inhibition of cell proliferation was completely blocked by 400-microM genistein, but the VK3 effect was reduced 72.8 +/- 5.4% by the same concentration of genistein. H(2)O(2)-induced JNK phosphorylation and ERK phosphorylation were inhibited by staurosporine, protein kinase C (PKC) inhibitor. VK3-induced JNK phosphorylation was also blocked, but ERK phosphorylation was not affected. Staurosporine had no effect on VK3- or H(2)O(2)-induced growth inhibition. Treatment with a non-thiol antioxidant agent, catalase, completely abrogated H(2)O(2)-induced JNK and ERK phosphorylation, but a thiol antioxidant, L: -cystein, had no effect on phosphorylation of them. The VK3-induced JNK phosphorylation was inhibited by catalase, but not L: -cystein. But ERK phosphorylation was not inhibited by catalase and was abrogated completely by the thiol antioxidant. Catalase, but not L: -cystein, blocked H(2)O(2)-induced growth inhibition, and L: -cystein, but not catalase, blocked VK3-induced effects on cell proliferation completely.
  
  
  CONCLUSIONS
  VK3-induced ERK phosphorylation occurs by a different mechanism from oxidative stress, and it might have an important role to induce growth inhibition.
authors.affiliation: Surgical Oncology, Gifu University School of Medicine, 1-1 Yanagido, Gifu city, 501-1194, Japan. sting@gifu-u.ac.jp
authors.forename: Shinji
authors.initials: S
authors.lastname: Osada
authors.forename: Fumio
authors.initials: F
authors.lastname: Sakashita
authors.forename: Yosiki
authors.initials: Y
authors.lastname: Hosono
authors.forename: Kenichi
authors.initials: K
authors.lastname: Nonaka
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Tokuyama
authors.forename: Hidenori
authors.initials: H
authors.lastname: Tanaka
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tomita
authors.forename: Shuji
authors.initials: S
authors.lastname: Komori
authors.forename: Satoshi
authors.initials: S
authors.lastname: Matsui
authors.forename: Takao
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D010190:Pancreatic Neoplasms / Q000201:enzymology / Q000473:pathology; D010766:Phosphorylation; D051381:Rats; D024483:Vitamin K 3 / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D024483:Vitamin K 3; D006861:Hydrogen Peroxide; D048049:Extracellular Signal-Regulated MAP Kinases