Cytotoxic Homo- and Hetero-Dimers of o-toluidine, o-anisidine, and Aniline Formed by In Vitro Metabolism
Cytotoxic Homo- and Hetero-Dimers of o-toluidine, o-anisidine, and Aniline Formed by In Vitro Metabolism
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体外代谢形成的邻甲苯胺、邻茴香胺和苯胺的细胞毒性同二聚体和异二聚体
DOI：
10.1021/acs.chemrestox.2c00226
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发表时间：
2022
影响因子：
4.1
通讯作者：
Miyoshi Noriyuki
中科院分区：
文献类型：
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作者：
Kobayashi Takuma;Kishimoto Shinji;Watanabe Shogo;Yoshioka Yasukiyo;Toyoda Takeshi;Ogawa Kumiko;Watanabe Kenji;Totsuka Yukari;Wakabayashi Keiji;Miyoshi Noriyuki
几种芳香胺化合物是膀胱致癌物。多环芳香胺如4-氨基联苯的活性代谢物和DNA加合物已被鉴定，而单环芳香胺如邻甲苯胺（o-Tol）、邻茴香胺（o-Ans）和苯胺（Ani）的活性代谢物和DNA加合物尚未完全确定。我们最近报道，Tol和Ans在体外和体内代谢转化为细胞毒性和致突变性的p-semidine型二聚体，即2-甲基-N4-（2-甲基苯基）苯-1，4-二胺（MMBD）和2-甲氧基-N4-（2-甲氧基苯基）苯-1，4-二胺（MxMxBD），分别表明它们在膀胱癌发生中的作用。在本研究中，我们发现，当no-Tol和do-Ans与S9混合物孵育时，形成了MMBD和MxMxBD以及两种异构异源二聚体MMxBD和MxMBD。因此，将任意两种ofo-Tol、o-Ans和Ani（各10 mM）与S9混合物孵育长达24 h，然后进行LC-MS分析，以研究其代谢动力学。观察到代谢转化为所有9种β-半胱氨酸型同源和异源二聚体，在与S9混合物孵育6 h时达到峰值; MxMxBD在6.1 ± 1.4 μM时达到峰值。在二胺结构中含有theo-Ans部分的均二聚体和异二聚体显示出更快的二聚化比率，而这些二聚体（如MxMxBD）的水平随着进一步孵育而显著下降。含有邻-Tol和Ani的二聚体即使在孵育24 h后也相对稳定。theo-Ans部分的供电子基团可能参与快速代谢转化。在细胞毒性试验中，在二胺结构和MMBD中具有ano-Ans部分的二聚体在人膀胱癌T24细胞中显示出比其他二聚体高约2至4倍的细胞毒性。单环芳香胺的同二聚体和异二聚体的这些化学和生物学特性在考虑膀胱癌发生的综合暴露风险时可能很重要。
Several aromatic amine compounds are urinary bladder carcinogens. Activated metabolites and DNA adducts of polycyclic aromatic amines, such as 4-aminobiphenyl, have been identified, whereas those of monocyclic aromatic amines, such aso-toluidine (o-Tol),o-anisidine (o-Ans), and aniline (Ani), have not been completely determined. We have recently reported thato-Tol ando-Ans are metabolically converted in vitro and in vivo to cytotoxic and mutagenicp-semidine-type dimers, namely 2-methyl-N4-(2-methylphenyl) benzene-1,4-diamine (MMBD) and 2-methoxy-N4-(2-methoxyphenyl) benzene-1,4-diamine (MxMxBD), respectively, suggesting their roles in urinary bladder carcinogenesis. In this study, we found that wheno-Tol ando-Ans were incubated with S9 mix, MMBD and MxMxBD as well as two isomeric heterodimers, MMxBD and MxMBD, were formed. Therefore, any two ofo-Tol,o-Ans, and Ani (10 mM each) were incubated with the S9 mix for up to 24 h and then subjected to LC–MS to investigate their metabolic kinetics. Metabolic conversions to all nine kinds ofp-semidine-type homo- and hetero-dimers were observed, peaking at 6 h of incubation with the S9 mix; MxMxBD reached the peak at 6.1 ± 1.4 μM. Homo- and hetero-dimers containing theo-Ans moiety in the diamine structure showed a faster dimerization ratio, whereas levels of these dimers, such as MxMxBD, markedly declined with further incubation. Dimers containingo-Tol and Ani were relatively stable, even after incubation for 24 h. The electron-donating group of theo-Ans moiety may be involved in rapid metabolic conversion. In the cytotoxic assay, dimers with ano-Ans moiety in the diamine structure and MMBD showed approximately two- to four-fold higher cytotoxicity than other dimers in human bladder cancer T24 cells. These chemical and biological properties of homo- and hetero-dimers of monocyclic aromatic amines may be important when considering the combined exposure risk for bladder carcinogenesis.