title: Nonsteroidal anti-inflammatory drug-activated gene-1 over expression in transgenic mice suppresses intestinal neoplasia.
abstract: OBJECTIVE
  The nonsteroidal anti-inflammatory drug-activated gene (NAG-1) was identified as a proapoptotic, antitumorigenic protein in vitro, induced by many antitumorigenic and chemopreventive drugs including cyclooxygenase inhibitors. However, its antitumorigenic activity has not been elucidated in vivo.
  
  
  METHODS
  Transgenic mice were generated that ubiquitously overexpress human NAG-1 under the control of a chicken beta-actin promoter (CAG). The NAG-1 transgenic mice (NAG-(Tg+)) were characterized, and then the antitumorigenic activity was evaluated with 2 colorectal carcinogenesis models: chemical induction with azoxymethane and genetic induction using the Apc(Min+) mutation.
  
  
  RESULTS
  NAG-(Tg+) showed no apparent phenotype other than a reduction in body weight, particularly in males. To examine whether NAG-1 expression would suppress intestinal tumorigenesis, the NAG-(Tg+) mice were treated with the colorectal carcinogen azoxymethane. NAG-(Tg+) mice developed 50% fewer aberrant crypt foci and no tumors, in comparison with nontransgenic littermates. This result demonstrates that expression of this human protein in vivo can suppress chemically induced carcinogenesis in the colon. The NAG-(Tg+) mice were also crossed with Apc(Min+) mice to determine the effect of the transgene on intestinal polyp formation. NAG-(Tg+) mice heterozygous for the Apc(Min+) mutation had a significantly reduced polyp load (60%) compared with nontransgenic Apc(Min+) littermates.
  
  
  CONCLUSIONS
  Our results support NAG-1 as an important regulator of intestinal adenoma growth in vivo and suggest that NAG-1 may act as a tumor suppressor gene.
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, USA.
authors.forename: Seung Joon
authors.initials: SJ
authors.lastname: Baek
authors.forename: Ryuji
authors.initials: R
authors.lastname: Okazaki
authors.forename: Seong-Ho
authors.initials: SH
authors.lastname: Lee
authors.forename: Jeanelle
authors.initials: J
authors.lastname: Martinez
authors.forename: Jong-Sik
authors.initials: JS
authors.lastname: Kim
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mishina
authors.forename: David W
authors.initials: DW
authors.lastname: Martin
authors.forename: Ahmed
authors.initials: A
authors.lastname: Shoieb
authors.forename: Michael F
authors.initials: MF
authors.lastname: McEntee
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Eling
mesh_terms: D000818:Animals; D016207:Cytokines / Q000235:genetics / Q000502:physiology*; D005260:Female; D017491:Genes, APC; D016147:Genes, Tumor Suppressor; D055436:Growth Differentiation Factor 15; D006801:Humans; D007414:Intestinal Neoplasms / Q000517:prevention & control*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009154:Mutation; D010641:Phenotype
chemical_list: D016207:Cytokines; C526140:GDF15 protein, human; C526141:Gdf15 protein, mouse; D055436:Growth Differentiation Factor 15