title: Comparative functional genomics analysis of NNK tobacco-carcinogen induced lung adenocarcinoma development in Gprc5a-knockout mice.
abstract: BACKGROUND
  Improved understanding of lung cancer development and progression, including insights from studies of animal models, are needed to combat this fatal disease. Previously, we found that mice with a knockout (KO) of G-protein coupled receptor 5A (Gprc5a) develop lung tumors after a long latent period (12 to 24 months).
  
  
  RESULTS
  To determine whether a tobacco carcinogen will enhance tumorigenesis in this model, we administered 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) i.p. to 2-months old Gprc5a-KO mice and sacrificed groups (n=5) of mice at 6, 9, 12, and 18 months later. Compared to control Gprc5a-KO mice, NNK-treated mice developed lung tumors at least 6 months earlier, exhibited 2- to 4-fold increased tumor incidence and multiplicity, and showed a dramatic increase in lesion size. A gene expression signature, NNK-ADC, of differentially expressed genes derived by transcriptome analysis of epithelial cell lines from normal lungs of Gprc5a-KO mice and from NNK-induced adenocarcinoma was highly similar to differential expression patterns observed between normal and tumorigenic human lung cells. The NNK-ADC expression signature also separated both mouse and human adenocarcinomas from adjacent normal lung tissues based on publicly available microarray datasets. A key feature of the signature, up-regulation of Ube2c, Mcm2, and Fen1, was validated in mouse normal lung and adenocarcinoma tissues and cells by immunohistochemistry and western blotting, respectively.
  
  
  CONCLUSIONS
  Our findings demonstrate that lung tumorigenesis in the Gprc5a-KO mouse model is augmented by NNK and that gene expression changes induced by tobacco carcinogen(s) may be conserved between mouse and human lung epithelial cells. Further experimentation to prove the reliability of the Gprc5a knockout mouse model for the study of tobacco-induced lung carcinogenesis is warranted.
authors.affiliation: Department of Thoracic/Head and Neck Medical Oncology, University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America.
authors.forename: Junya
authors.initials: J
authors.lastname: Fujimoto
authors.forename: Humam
authors.initials: H
authors.lastname: Kadara
authors.forename: Taoyan
authors.initials: T
authors.lastname: Men
authors.forename: Carolyn
authors.initials: C
authors.lastname: van Pelt
authors.forename: Dafna
authors.initials: D
authors.lastname: Lotan
authors.forename: Reuben
authors.initials: R
authors.lastname: Lotan
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics*; D000818:Animals; D015153:Blotting, Western; D002273:Carcinogens / Q000633:toxicity*; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism; D045585:Flap Endonucleases / Q000235:genetics / Q000378:metabolism; D023281:Genomics / Q000379:methods*; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008175:Lung Neoplasms / Q000235:genetics*; D051379:Mice; D018345:Mice, Knockout; D009602:Nitrosamines / Q000633:toxicity*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000502:physiology*; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics / Q000378:metabolism
chemical_list: D002273:Carcinogens; D009602:Nitrosamines; D009687:Nuclear Proteins; D043562:Receptors, G-Protein-Coupled; D019938:Cyclin D1; C016583:4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone; D044763:Ubiquitin-Conjugating Enzymes; D045585:Flap Endonucleases