Study of DNA methylation by tobacco-specific N-nitrosamines

Journal Article · Tue Oct 01 04:00:00 EDT 1985 · Environ. Health Perspect.; (United States)

DOI:https://doi.org/10.1289/ehp.8562197· OSTI ID:5387065

Castonguay, A; Foiles, P G; Trushin, N; Hecht, S S

An enzyme-linked immunosorbent assay (BA-ELISA) involving use of biotin-labeled anti-rabbit IgG and avidin-labeled horseradish peroxidase was developed for the measurement of O/sup 6/-methyl-2'-deoxyguanosine (O/sup 6/-MedGuo). Up to 5..mu..g of methylated DNA was enzymatically hydrolyzed, and the extent of inhibition of binding of immobilized O/sup 6/-MedGuo-bovine serum albumin to rabbit anio-O/sup 6/-MedGuo was measured. Among the tobacco-related carcinogens, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is one of the most potent. In F344 rats it induces nasal cavity, lung and liver tumors. Four hours after a single IV injection of NNK to F344 rats O/sup 6/-MedGuo was present in target organs but was not detectable in nontarget organs. F344 rats receiving daily IP injections of NNK for 14 days were sacrificed 24 hr after the last injection. The levels of (O/sup 6/-Medguo/dGuo) were 7.9 and 11.4 ..mu..mole/mole in the nasal mucosa and lung, respectively. In the liver no O/sup 6/-MedGuo was detected, but 1050 ..mu..mole of 7-MeGua/mole Gua was measured by HPLC-fluorimetry. No DNA methylation was observed in the nasal mucosa or liver of F344 rats treated with the nicotine-derived carcinogen N'-nitrosonornicotine. Nasal mucosae were cultured in vitro with NNk or NNAl. After 1 hr, methylation at the O/sup 6/-dGuo and 7-dGuo sites were observed with NNK but not with NNAl. These results suggest that NNAl is not associated with the activation of NNK to DNA methylating species.

• Research Organization: Naylor Dana Institute for Disease Prevention, Valhalla, NY
• OSTI ID: 5387065
• Journal Information: Environ. Health Perspect.; (United States), Journal Name: Environ. Health Perspect.; (United States) Vol. 62; ISSN EVHPA
• Country of Publication: United States
• Language: English

Related Subjects

550200 -- Biochemistry
560305* -- Chemicals Metabolism & Toxicology-- Vertebrates-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADDUCTS
AMINES
ANIMALS
BODY
CHEMICAL REACTIONS
DIGESTIVE SYSTEM
DNA
DNA ADDUCTS
ENZYME IMMUNOASSAY
GLANDS
IMMUNOASSAY
LIVER
LUNGS
MAMMALS
MEMBRANES
METABOLIC ACTIVATION
METHYLATION
MUCOUS MEMBRANES
NITROSAMINES
NITROSO COMPOUNDS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PHARYNX
RATS
RESPIRATORY SYSTEM
RODENTS
VERTEBRATES