Molecular Changes in the Nasal Cavity after N, N-dimethyl-p-toluidine Exposure.
N, N-dimethyl-p-toluidine (DMPT; Cas No. 99-97-8), an accelerant for methyl methacrylate monomers in medical devices, is a nasal cavity carcinogen according to a 2-yr cancer study of male and female F344/N rats, with the nasal tumors arising from the transitional cell epithelium. In this study, we exposed male F344/N rats for 5 days to DMPT (0, 1, 6, 20, 60, or 120 mg/kg [oral gavage]) to explore the early changes in the nasal cavity after short-term exposure. Lesions occurred in the nasal cavity including hyperplasia of transitional cell epithelium (60 and 120 mg/kg). Nasal tissue was rapidly removed and preserved for subsequent laser capture microdissection and isolation of the transitional cell epithelium (0 and 120 mg/kg) for transcriptomic studies. DMPT transitional cell epithelium gene transcript patterns were characteristic of an antioxidative damage response (e.g., Akr7a3, Maff, and Mgst3), cell proliferation, and decrease in signals for apoptosis. The transcripts of amino acid transporters were upregulated (e.g., Slc7a11). The DMPT nasal transcript expression pattern was similar to that found in the rat nasal cavity after formaldehyde exposure, with over 1,000 transcripts in common. Molecular changes in the nasal cavity after DMPT exposure suggest that oxidative damage is a mechanism of the DMPT toxic and/or carcinogenic effects.
Toxicology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA dunnickj@niehs.nih.gov.
June K
JK
Dunnick
Biomolecular Screening Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
B Alex
BA
Merrick
Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina, USA.
Amy
A
Brix
NTP Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
Daniel L
DL
Morgan
Molecular Genomics Core, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
Kevin
K
Gerrish
Cellular and Molecular Pathology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
Yu
Y
Wang
Cellular and Molecular Pathology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
Gordon
G
Flake
Cellular and Molecular Pathology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
Julie
J
Foley
Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
Keith R
KR
Shockley
D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D004847:Epithelial Cells / Q000187:drug effects* / Q000473:pathology*; D008297:Male; D009296:Nasal Cavity / Q000187:drug effects* / Q000473:pathology*; D051381:Rats; D011916:Rats, Inbred F344; D014052:Toluidines / Q000633:toxicity*; D059467:Transcriptome / Q000187:drug effects
D002273:Carcinogens; D014052:Toluidines; C015835:dimethyl-4-toluidine
N; N-dimethyl-p-toluidine; molecular markers; nasal cavity toxicity