Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Auerbachstr. 112, 70376, Stuttgart, Germany.
University of Tuebingen, Tuebingen, Germany.
Arch Toxicol. 2017 Oct;91(10):3329-3339. doi: 10.1007/s00204-017-1955-4. Epub 2017 Mar 22.
Methyleugenol is a rodent hepatocarcinogen occurring in many herbs and spices as well as essential oils used for flavoring. Following metabolic activation by cytochromes P450 (CYPs) and sulfotransferases (SULTs), methyleugenol can form DNA adducts. Previously, we showed that DNA adduct formation by methyleugenol in mouse liver is dependent on SULT1A1 expression and that methyleugenol DNA adducts are abundant in human liver specimens. In humans, SULT1A1 activity is affected by genetic polymorphisms, including single-nucleotide polymorphisms (SNPs) and copy number variations (CNVs). Here we investigated the relationship between individual methyleugenol DNA adduct levels and SULT1A1 in human liver samples. Using isotope-dilution ultraperformance liquid chromatography coupled with tandem mass spectrometry, we quantified methyleugenol DNA adducts in 121 human surgical liver samples. Frequent CNVs, including deletions (f = 3.3%) and duplications (f = 36.4%) of SULT1A1, were identified using qPCR and TaqMan assays in the donors' genomic DNA. SULT1A1 mRNA and protein levels were quantified using microarray data and Western blot analysis, respectively. Methyleugenol DNA adducts were detected in all 121 liver samples studied. Their levels varied 122-fold between individuals and were significantly correlated to both mRNA and protein levels of SULT1A1 (r = 0.43, and r = 0.44, respectively). Univariate and multivariate statistical analysis identified significant associations of SULT1A1 CNVs with mRNA (p = 1.7 × 10) and protein (p = 4.4 × 10) levels as well as methyleugenol DNA adduct levels (p = 0.003). These data establish the importance of SULT1A1 genotype for hepatic methyleugenol DNA adducts in humans, and they confirm a strong impact of SULT1A1 CNVs on SULT1A1 hepatic phenotype.
甲基丁香酚是一种啮齿动物肝致癌物，存在于许多草药和香料以及用于调味的精油中。在细胞色素 P450（CYPs）和磺基转移酶（SULTs）代谢激活后，甲基丁香酚可以形成 DNA 加合物。此前，我们表明，小鼠肝中甲基丁香酚形成 DNA 加合物依赖于 SULT1A1 的表达，并且人肝标本中存在丰富的甲基丁香酚 DNA 加合物。在人类中，SULT1A1 活性受遗传多态性影响，包括单核苷酸多态性（SNPs）和拷贝数变异（CNVs）。在这里，我们研究了人类肝样本中个体甲基丁香酚 DNA 加合物水平与 SULT1A1 之间的关系。我们使用同位素稀释超高效液相色谱-串联质谱法定量分析了 121 个人类手术肝样本中的甲基丁香酚 DNA 加合物。使用 qPCR 和 TaqMan 测定法在供体基因组 DNA 中鉴定了 SULT1A1 的频繁 CNVs，包括缺失（f = 3.3%）和重复（f = 36.4%）。使用微阵列数据和 Western blot 分析分别定量 SULT1A1 的 mRNA 和蛋白水平。在所研究的 121 个肝样本中均检测到甲基丁香酚 DNA 加合物。它们的水平在个体之间变化了 122 倍，与 SULT1A1 的 mRNA（r = 0.43）和蛋白（r = 0.44）水平显著相关。单变量和多变量统计分析确定了 SULT1A1 CNVs 与 mRNA（p = 1.7×10）和蛋白（p = 4.4×10）水平以及甲基丁香酚 DNA 加合物水平（p = 0.003）显著相关。这些数据确立了 SULT1A1 基因型对人类肝中甲基丁香酚 DNA 加合物的重要性，并证实了 SULT1A1 CNVs 对 SULT1A1 肝表型的强烈影响。
