title: Sodium nitroprusside (SNP) sensitizes human gastric cancer cells to TRAIL-induced apoptosis.
abstract: OBJECTIVE
  To investigate the effects of the nitrous oxide (NO)-donor sodium nitroprusside (SNP) on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis in human gastric cancer cells.
  
  
  METHODS
  The MTT assay and flow cytometry were used to detect cellular proliferation and markers of apoptosis, respectively. Expression levels of caspases-8, and 9 were determined by Western blot. Changes in Nitric Oxide Synthase (NOS) activity, NO production, and caspase activation were also evaluated.
  
  
  RESULTS
  We found that TRAIL induced apoptosis and cell cycle arrest in human gastric cancer cell lines, and that this effect was mediated by NO production, and activation of both the extrinsic and intrinsic signaling pathways of apoptosis. In addition, we found that the NO-donor SNP sensitizes gastric cancer cells to TRAIL-mediated apoptosis. Treatment of cells with both TRAIL and SNP resulted in increased activation of caspase-8 and caspase-9 and NO release. Inhibition of caspase-8 blocked cell TRAIL-induced apoptosis, while a selective caspase-9 inhibitor was unable to prevent apoptosis induced by either TRAIL or TRAIL plus SNP. Inhibition of NOS could block the activation of caspase-9, but had no obvious effect on cell apoptosis.
  
  
  CONCLUSIONS
  SNP-sensitized gastric cancer cells to TRAIL-induced cytotoxicity by stimulating the release of NO, in turn facilitating the mitochondria-mediated signal transduction pathway. The engagement of the mitochondria signaling pathways along with the TRAIL death receptor signaling pathway synergistically increase levels of apoptosis in these cells.
authors.affiliation: Department of Gastroenterology, Third Military Medical University, Chongqing, China.
authors.forename: Liuqin
authors.initials: L
authors.lastname: Yang
authors.forename: Chunhui
authors.initials: C
authors.lastname: Lan
authors.forename: Yu
authors.initials: Y
authors.lastname: Fang
authors.forename: Yafei
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Guo
authors.forename: Shunmei
authors.initials: S
authors.lastname: Wan
authors.forename: Shiming
authors.initials: S
authors.lastname: Yang
authors.forename: Rongquan
authors.initials: R
authors.lastname: Wang
authors.forename: Dianchun
authors.initials: D
authors.lastname: Fang
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D053181:Caspase 8 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045744:Cell Line, Tumor; D004351:Drug Resistance / Q000187:drug effects; D004357:Drug Synergism; D006801:Humans; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors; D009599:Nitroprusside / Q000494:pharmacology*; D009842:Oligopeptides / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000473:pathology; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology
chemical_list: D020030:Nitric Oxide Donors; D009842:Oligopeptides; D011994:Recombinant Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C403753:benzyloxycarbonyl-isoleucyl-glutamyl-threonyl-aspartic acid fluoromethyl ketone; C403754:benzyloxycarbonyl-leucyl-glutamyl-histidyl-aspartic acid fluoromethyl ketone; D009599:Nitroprusside; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D053181:Caspase 8; D053453:Caspase 9; D019331:NG-Nitroarginine Methyl Ester
keywords: Apoptosis; Caspases; Cell cycle; NO; SNP; TRAIL