DNA and protein adduct formation in the colon and blood of humans after exposure to a dietary-relevant dose of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine.

:Epidemiology studies have indicated that certain dietary components, including well-cooked meat, are risk determinants for colon cancer. Cooked meat can contain significant quantities of heterocyclic aromatic amines (HCAs), which have been established as carcinogens in laboratory animals. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is usually the most mass-abundant HCA, with concentrations up to 480 ppb. We used accelerator mass spectrometry to establish whether DNA and protein adducts can be detected in humans exposed to a quantity of PhIP comparable with levels of exposure that occur in the diet. Five human volunteers were administered a dietary-relevant dose of [14C]PhIP (70-84 microg) 48-72 h before surgery for removal of colon tumors. Blood samples were collected at various time points, and albumin, hemoglobin, and WBC DNA were extracted for analysis by accelerator mass spectrometry. Tissue samples were collected during surgery and used to assess either tissue available doses of [14C]PhIP or adduct levels. The results of this study show: (a) PhIP is activated to a form that will bind to albumin, hemoglobin, and WBC DNA in peripheral blood. WBC DNA adducts were unstable and declined substantially over 24 h; (b) PhIP is bioavailable to the colon, with levels in normal tissue in the range 42-122 pg PhIP/g tissue; and (c) PhIP binds to both protein and DNA in the colon. DNA adduct levels in the normal tissue were 35-135 adducts/10(12) nucleotides, which was significantly lower than tumor tissue. The results of this study demonstrate that PhIP is bioavailable to the human colon following defined dietary-relevant doses and forms DNA and protein adducts.

Dingley KH ，Curtis KD ，Nowell S ，Felton JS ，Lang NP ，Turteltaub KW ... -  《CANCER EPIDEMIOLOGY BIOMARKERS & PREVENTION》

Detection of 2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine-DNA adducts in normal breast tissues and risk of breast cancer.

Zhu J ，Chang P ，Bondy ML ，Sahin AA ，Singletary SE ，Takahashi S ，Shirai T ，Li D ... -  《CANCER EPIDEMIOLOGY BIOMARKERS & PREVENTION》

The urinary metabolite profile of the dietary carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine is predictive of colon DNA adducts after a low-dose exposure in humans.

Malfatti MA ，Dingley KH ，Nowell-Kadlubar S ，Ubick EA ，Mulakken N ，Nelson D ，Lang NP ，Felton JS ，Turteltaub KW ... -  《-》

Formation of protein adducts of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in cooked foods.

Kataoka H ，Miyake M ，Nishioka S ，Matsumoto T ，Saito K ，Mitani K ... -  《-》

Assessment of the DNA adduction and pharmacokinetics of PhIP and MeIOx in rodents at doses approximating human exposure using the technique of accelerator mass spectrometry (AMS) and 32P-postlabeling.

Turteltaub KW ，Vogel JS ，Frantz C ，Felton JS ，McManus M ... -  《-》