title: N-nitroso compound exposure-associated transcriptomic profiles are indicative of an increased risk for colorectal cancer.
abstract: Endogenous formation of N-nitroso compounds (NOCs), which are known animal carcinogens, could contribute to human carcinogenesis but definitive evidence is still lacking. To investigate the relevance of NOCs in human colorectal cancer (CRC) development, we analyzed whole genome gene expression modifications in human colon biopsies in relation to fecal NOC exposure. We had a particular interest in patients suffering from intestinal inflammation as this may stimulate endogenous NOC formation, and consequently predispose to CRC risk. Inflammatory bowel disease (IBD) patients diagnosed with ulcerative colitis and irritable bowel syndrome patients without inflammation, serving as controls, were therefore recruited. Fecal NOC were demonstrated in the majority of subjects. By associating gene expression levels of all subjects to fecal NOC levels, we identified a NOC exposure-associated transcriptomic response that suggests that physiological NOC concentrations may potentially induce genotoxic responses and chromatin modifications in human colon tissue, both of which are linked to carcinogenicity. In a network analysis, chromatin modifications were linked to 11 significantly modulated histone genes, pointing towards a possible epigenetic mechanism that may be relevant in comprehending NOC-induced carcinogenesis. In addition, pro-inflammatory transcriptomic modifications were identified in visually non-inflamed regions of the IBD colon. However, fecal NOC levels were slightly but not significantly increased in IBD patients, suggesting that inflammation did not strongly stimulate NOC formation. We conclude that NOC exposure is associated with gene expression modifications in the human colon that may suggest a potential role of these compounds in CRC development.
authors.affiliation: Department of Toxicogenomics, Maastricht University, Maastricht, The Netherlands. d.hebels@maastrichtuniversity.nl
authors.forename: Dennie G A J
authors.initials: DG
authors.lastname: Hebels
authors.forename: Kirstine M
authors.initials: KM
authors.lastname: Sveje
authors.forename: Marloes C
authors.initials: MC
authors.lastname: de Kok
authors.forename: Marcel H M
authors.initials: MH
authors.lastname: van Herwijnen
authors.forename: Gunter G C
authors.initials: GG
authors.lastname: Kuhnle
authors.forename: Leopold G J B
authors.initials: LG
authors.lastname: Engels
authors.forename: Carla B E M
authors.initials: CB
authors.lastname: Vleugels-Simon
authors.forename: Wout G N
authors.initials: WG
authors.lastname: Mares
authors.forename: Marieke
authors.initials: M
authors.lastname: Pierik
authors.forename: Ad A M
authors.initials: AA
authors.lastname: Masclee
authors.forename: Jos C S
authors.initials: JC
authors.lastname: Kleinjans
authors.forename: Theo M C M
authors.initials: TM
authors.lastname: de Kok
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced; D003106:Colon / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D015179:Colorectal Neoplasms / Q000139:chemically induced; D005243:Feces / Q000737:chemistry; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009603:Nitroso Compounds / Q000032:analysis / Q000378:metabolism / Q000633:toxicity
chemical_list: D009603:Nitroso Compounds