Department of Drug Safety Sciences, Division of Clinical Pharmacology, Nagoya University Graduate School of Medicine.
Department of Molecular and Environmental Pathology, Institute of Health Biosciences, Tokushima University Graduate School.
J Toxicol Sci. 2020;45(8):493-502. doi: 10.2131/jts.45.493.
Gefitinib (GEF) is the first selective tyrosine kinase inhibitor of epidermal growth factor receptor. It is associated with the occurrence of clinical drug-induced liver injury. Although GEF is metabolized to chemically reactive metabolites by cytochrome P450 3A and 1A enzymes and then conjugated to glutathione (GSH), whether these reactive metabolites contribute to GEF-induced toxicity remains unknown. In this study, we investigated whether GSH depletion can sensitize mice to liver injury caused by GEF. Male C57BL/6J mice were intraperitoneally pretreated with L-buthionine (S,R)-sulfoximine (BSO) at 700 mg/kg to inhibit GSH synthesis and then orally administered GEF at 500 mg/kg every 24 hr for 4 consecutive days. The coadministration of BSO and GEF increased plasma alanine aminotransferase (ALT) levels to approximately 700 U/L and 1600 U/L at 72 and 96 hr after the first administration, respectively, whereas the increase in plasma ALT levels in mice receiving GEF at 500 mg/kg alone was limited, suggesting that GSH plays a protective role in GEF-induced liver injury. Histological examination showed nuclear karyorrhexis and sporadic single hepatocyte death in the livers of BSO+GEF coadministered mice. In these mice, the hepatic expression levels of heme oxygenase 1 (Hmox1) and metallothionein 2 (Mt2) mRNA, caspase 3/7 enzymatic activity, and the amounts of 2-thiobarbiuric acid reactive substances were significantly increased, suggesting the presence of oxidative stress, which may be associated with hepatocellular death. Together, these results show that oxidative stress as well as the reactive metabolites of GEF are involved in GEF-induced liver injury in GSH-depleted mice.
吉非替尼（GEF）是表皮生长因子受体的第一个选择性酪氨酸激酶抑制剂。它与临床药物诱导的肝损伤的发生有关。虽然 GEF 可被细胞色素 P450 3A 和 1A 酶代谢为化学活性代谢物，然后与谷胱甘肽（GSH）结合，但这些活性代谢物是否导致 GEF 诱导的毒性尚不清楚。在这项研究中，我们研究了 GSH 耗竭是否可以使小鼠对 GEF 引起的肝损伤敏感。雄性 C57BL/6J 小鼠用 L-丁硫氨酸（S，R）-亚砜亚胺（BSO）以 700mg/kg 腹膜内预处理以抑制 GSH 合成，然后每天口服 GEF 500mg/kg，连续 4 天，每天 24 小时一次。BSO 和 GEF 的共同给药使血浆丙氨酸氨基转移酶（ALT）水平分别在第一次给药后 72 和 96 小时增加到约 700U/L 和 1600U/L，而单独给予 GEF 500mg/kg 的小鼠血浆 ALT 水平的增加是有限的，这表明 GSH 在 GEF 诱导的肝损伤中起保护作用。组织学检查显示 BSO+GEF 共同给药小鼠的肝脏核碎裂和散在的单个肝细胞死亡。在这些小鼠中，血红素加氧酶 1（Hmox1）和金属硫蛋白 2（Mt2）mRNA 的肝表达水平、半胱天冬酶 3/7 酶活性以及 2-硫代巴比妥酸反应物质的量均显着增加，表明存在氧化应激，这可能与肝细胞死亡有关。总之，这些结果表明，氧化应激以及 GEF 的活性代谢物参与了 GSH 耗竭小鼠中 GEF 诱导的肝损伤。
