Role of human sulfotransferase 1A1 and N-acetyltransferase 2 in the metabolic activation of 16 heterocyclic amines and related heterocyclics to genotoxicants in recombinant V79 cells

Abstract

Heterocyclic aromatic amines (HAAs) are primarily produced during the heating of meat or fish. HAAs are mutagenic and carcinogenic, and their toxicity in model systems depend on metabolic activation. This activation is mediated by cytochrome P450 (CYP) enzymes, in particular CYP1A2. Some studies have indicated a role of human sulfotransferase (SULT) 1A1 and N-acetyltransferase (NAT) 2 in the terminal activation of HAAs. In this study, we conducted a metabolism/genotoxicity relationship analysis for 16 HAAs and related heterocyclics. We used the γH2AX genotoxicity assay in V79 cells (deficient in CYP, SULT and NAT) and V79-derived cell lines genetically engineered to express human CYP1A2 alone or in combination with human SULT1A1 or NAT2. Our data demonstrated genotoxic properties for 13 out of the 16 compounds tested. A clear relationship between metabolic bioactivation and genotoxicity allowed to distinguish four groups: (1) Trp-P-1 genotoxicity was linked to CYP1A2 bioactivation only-with negligible effects of phase II enzymes; (2) Glu-P-2, Glu-P-1, Trp-P-2, APNH, MeAαC and AαC were bioactivated by CYP1A2 in combination with either phase II enzyme tested (NAT2 or SULT1A1); (3) IQ, 4-MeIQ, IQx, 8-MeIQx, and 4,8-DiMeIQx required CYP1A2 in combination with NAT2 to be genotoxic, whereas SULT1A1 did not enhance their genotoxicity; (4) PhIP became genotoxic after CYP1A2 and SULT1A1 bioactivation-NAT2 had not effect. Our results corroborate some previous data regarding the genotoxic potency of seven HAAs and established the genotoxicity mechanism for five others HAAs. This study also permits to compare efficiently the genotoxic potential of these 13 HAAs.

Role of Human N‐Acetyltransferase 2 Genetic Polymorphism on Aromatic Amine Carcinogen‐Induced DNA Damage and Mutagenicity in a Chinese Hamster Ovary Cell Mutation Assay

“…The results differed with the heterocyclic amine carcinogen tested, as rapid acetylator NAT2*4 did not affect levels of mutagenesis and DNA adduct formation following incubation with PhIP (Metry et al 2007) whereas both mutagenesis and DNA adduct formation were markedly higher in CHO cells possessing rapid acetylator NAT2*4 following incubation with IQ or MeIQx (Metry et al 2010). The conclusion that NAT2 is necessary for the DNA damage and mutagenesis induced by MeIQx and IQ but not PhIP was recently confirmed in V79 Chinese hamster cells (Chevereau et al 2017). Our laboratory also reported higher levels of ABP-induced hprt mutants and DNA adducts in DNA repair-deficient CHO cells transfected with CYP1A1 and NAT2*4 ).…”

“…Similar findings have been reported following administration of heterocyclic amines MeIQx and IQ (Metry et al 2010) but not PhIP (Metry et al 2007). More recently, it was confirmed that transfection of human NAT2 into V79 Chinese hamster cells increases mutagenicity of MeIQx and IQ, but not PhIP (Chevereau et al 2017).…”

Genotoxicity of 11 heavy metals detected as food contaminants in two human cell lines

“…The In‐Cell Western technique was performed as previously described [Graillot et al, ; Khoury et al, ,b; Chevereau et al, ]. Briefly, after the treatment, cells were fixed with 4% paraformaldehyde (Electron Microscopy Science) in phosphate buffered saline (PBS) and permeabilized with 0.2% Triton X‐100.…”

“…LOAEC (Lowest Observed Adverse Effect Concentration) parameter for each metalloid was based on the first concentration for which we observed genotoxicity. Genotoxicity was considered positive only if three criteria were all fulfilled: (1) The compound caused a 1.3‐fold increase in γH2AX, (2) there was a statistically significant difference compared to controls and (3) a level of cytotoxicity below 50% of the controls was observed [Graillot et al, ; Khoury et al, ,b; Chevereau et al, ].…”

Isolation and structure elucidation of constituents of Citrus limon, Isodon japonicus, and Lansium domesticum as the cancer prevention agents

“…Among them, furanocoumarins showed the strongest antimutagenic effects in the Ames test. It is important to note that furanocoumarins were well known Cytochrome P450 (CYP) 1A2 inhibitors [45], and the mutagenicity of Trp-P-1 and PhIP depends on their bioactivation by CYP 1A2 [46]. These facts suggest that one of the mechanisms of the antimutagenic effects of furanocoumarins against Trp-P-1 and PhIP may be the inhibition of the CYP 1A2 enzyme.…”