Martins Célia, Oliveira Nuno G, Pingarilho Marta, Gamboa da Costa Gonçalo, Martins Vanda, Marques M Matilde, Beland Frederick A, Churchwell Mona I, Doerge Daniel R, Rueff José, Gaspar Jorge Francisco
Department of Genetics, Faculty of Medical Sciences, New University of Lisbon, 1349-008 Lisboa, Portugal.
Toxicol Sci. 2007 Feb;95(2):383-90. doi: 10.1093/toxsci/kfl155. Epub 2006 Nov 6.
Acrylamide (AA) is a suspected human carcinogen generated in carbohydrate-rich foodstuffs upon heating. Glycidamide (GA), formed via epoxidation, presumably mediated by cytochrome P450 2E1, is thought to be the active metabolite playing a central role in AA genotoxicity. In this work we investigated DNA damage induced by AA and GA in mammalian cells, using V79 Chinese hamster cells. For this purpose, we evaluated two cytogenetic end points, chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs), as well as the levels of specific GA-DNA adducts, namely, N7-(2-carbamoyl-2-hydroxyethyl)guanine (N7-GA-Gua) and N3-(2-carbamoyl-2-hydroxyethyl)adenine (N3-GA-Ade) using high-performance liquid chromatography coupled with tandem mass spectrometry. GA was more cytotoxic and clastogenic than AA. Both AA and GA induced CAs (breaks and gaps) and decreased the mitotic index. GA induced SCEs in a dose-responsive manner; with AA, SCEs were increased at only the highest dose tested (2mM). A linear dose-response relationship was observed between the GA concentration and the levels of N7-GA-Gua. This adduct was detected for concentrations as low as 1 microM GA. N3-GA-Ade was also detected, but only at very high GA concentrations (>or= 250 microM). There was a very strong correlation between the levels of N7-GA-Gua in the GA- and AA-treated cells and the extent of SCE induction. Such correlation was not apparent for CAs. These data suggest that the induction of SCEs by AA is associated with the metabolism of AA to GA and subsequent formation of depurinating DNA adducts; however, other mechanisms must be involved in the induction of CAs.
丙烯酰胺（AA）是一种在富含碳水化合物的食品加热过程中产生的疑似人类致癌物。缩水甘油酰胺（GA）是通过环氧化作用形成的，推测由细胞色素P450 2E1介导，被认为是在AA遗传毒性中起核心作用的活性代谢产物。在这项工作中，我们使用V79中国仓鼠细胞研究了AA和GA在哺乳动物细胞中诱导的DNA损伤。为此，我们评估了两个细胞遗传学终点，即染色体畸变（CAs）和姐妹染色单体交换（SCEs），以及特定GA-DNA加合物的水平，即使用高效液相色谱-串联质谱法检测N7-（2-氨基甲酰基-2-羟乙基）鸟嘌呤（N7-GA-Gua）和N3-（2-氨基甲酰基-2-羟乙基）腺嘌呤（N3-GA-Ade）。GA比AA具有更强的细胞毒性和致断裂性。AA和GA都诱导了CAs（断裂和间隙）并降低了有丝分裂指数。GA以剂量反应方式诱导SCEs；对于AA，仅在测试的最高剂量（2mM）下SCEs增加。在GA浓度与N7-GA-Gua水平之间观察到线性剂量反应关系。对于低至1 microM GA的浓度也检测到了这种加合物。还检测到了N3-GA-Ade，但仅在非常高的GA浓度（≥250 microM）下。在GA和AA处理的细胞中，N7-GA-Gua的水平与SCE诱导程度之间存在非常强的相关性。对于CAs，这种相关性并不明显。这些数据表明，AA诱导SCEs与AA代谢为GA以及随后形成脱嘌呤DNA加合物有关；然而，其他机制必定参与了CAs的诱导。
