title: RNA-sequencing studies identify genes differentially regulated during inflammation-driven lung tumorigenesis and targeted by chemopreventive agents.
abstract: BACKGROUND
  Chronic pulmonary inflammation has been consistently shown to increase the risk of lung cancer. Therefore, assessing the molecular links between the two diseases and identification of chemopreventive agents that inhibit inflammation-driven lung tumorigenesis is indispensable.
  
  
  METHODS
  Female A/J mice were treated with the tobacco smoke carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and lipopolysaccharide (LPS), a potent inflammatory agent and constituent of tobacco smoke, and maintained on control diet or diet supplemented with the chemopreventive agents indole-3-carbinol (I3C) and/or silibinin (Sil). At the end of the study, mice were sacrificed and tumors on the surface of the lung were counted and gene expression levels in lung tissues were determined by RNA sequencing.
  
  
  RESULTS
  The mean number of lung tumors induced by NNK and NNK + LPS was 5 and 15 tumors/mouse, respectively. Dietary supplementation with the combination of I3C and Sil significantly reduced the size and multiplicity (by 50 %) of NNK + LPS-induced lung tumors. Also, we found that 330, 2957, and 1143 genes were differentially regulated in mice treated with NNK, LPS, and NNK + LPS, respectively. The inflammatory response of lung tumors to LPS, as determined by the number of proinflammatory genes with altered gene expression or the level of alteration, was markedly less than that of normal lungs. Among 1143 genes differentially regulated in the NNK + LPS group, the expression of 162 genes and associated signaling pathways was significantly modulated by I3C and/or Sil + I3C. These genes include cytokines, chemokines, putative oncogenes and tumor suppressor genes and Ros1, AREG, EREG, Cyp1a1, Arntl, and Npas2.
  
  
  CONCLUSIONS
  To our knowledge, this is the first report that provides insight into genes that are differentially expressed during inflammation-driven lung tumorigenesis and the modulation of these genes by chemopreventive agents.
authors: Masonic Cancer Center, University of Minnesota, Mayo Mail Code 806, 420 Delaware Street SE, Minneapolis, MN, 55455, USA.
authors: Xuemin
authors: X
authors: Qian
authors: Ali
authors: A
authors: Khammanivong
authors: Jung Min
authors: JM
authors: Song
authors: Fitsum
authors: F
authors: Teferi
authors: Pramod
authors: P
authors: Upadhyaya
authors: Erin
authors: E
authors: Dickerson
authors: Fekadu
authors: F
authors: Kassie
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D002273:Carcinogens / Q000494:pharmacology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D007211:Indoles / Q000494:pharmacology; D007249:Inflammation / Q000150:complications* / Q000235:genetics*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008168:Lung / Q000473:pathology; D008175:Lung Neoplasms / Q000209:etiology* / Q000235:genetics*; D051379:Mice; D008805:Mice, Inbred A; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D017423:Sequence Analysis, RNA; D000077385:Silybin; D012838:Silymarin / Q000494:pharmacology
chemical_list: D016588:Anticarcinogenic Agents; D002273:Carcinogens; D007211:Indoles; D008070:Lipopolysaccharides; D012838:Silymarin; D000077385:Silybin; D012313:RNA; C016517:indole-3-carbinol