硫氧还蛋白还原酶 1 (TXNRD1) 已被确定为癌细胞中有希望的化疗靶点之一。因此，新型TXNRD1抑制剂可以加速临床抗癌研究中的化疗。在这项研究中，glaucocalyxin A (GlauA) 是一种从 Rabdosia japonica var. 中提取的天然二萜。 glaucocalyx 被鉴定为 TXNRD1 的新型抑制剂。我们发现 GlauA 有效抑制重组 TXNRD1 并降低其在胃癌细胞中的活性，而不影响该酶的表达水平。从机制上讲，TXNRD1 的硒代半胱氨酸残基 (U498) 通过 Michael 加成被 GlauA 不可逆地修饰。此外，GlauA 与谷胱甘肽 (GSH) 形成共价加合物，并通过消耗细胞 GSH 来破坏细胞氧化还原平衡。 GlauA 对 TXNRD1 的抑制和 GSH 的消耗使其在 AGS 细胞的球体培养和 Transwell 测定中具有细胞毒性作用。通过添加 DTT 和 β-ME 等还原剂，可以减轻二硫键应激诱导的 GlauA 细胞毒性。此外，FDA 批准的药物金诺芬（一种 TXNRD1 抑制剂）在 AGS 细胞中引发细胞骨架蛋白 Talin-1 的寡聚化，表明抑制 TXNRD1 会引发二硫键应激。总之，这项研究发现 GlauA 是 TXNRD1 的有效抑制剂，并证明了 TXNRD1 抑制通过破坏氧化还原稳态和诱导二硫键应激作为有效抗癌策略的潜力。© 2024 欧洲生化协会联合会。

Thioredoxin reductase 1 (TXNRD1) has been identified as one of the promising chemotherapeutic targets in cancer cells. Therefore, a novel TXNRD1 inhibitor could accelerate chemotherapy in clinical anticancer research. In this study, glaucocalyxin A (GlauA), a natural diterpene extracted from Rabdosia japonica var. glaucocalyx, was identified as a novel inhibitor of TXNRD1. We found that GlauA effectively inhibited recombinant TXNRD1 and reduced its activity in gastric cancer cells without affecting the enzyme's expression level. Mechanistically, the selenocysteine residue (U498) of TXNRD1 was irreversibly modified by GlauA through a Michael addition. Additionally, GlauA formed a covalent adduct with glutathione (GSH) and disrupted cellular redox balance by depleting cellular GSH. The inhibition of TXNRD1 and depletion of GSH by GlauA conferred its cytotoxic effects in spheroid culture and Transwell assays in AGS cells. The disulfide stress induced cytotoxicity of GlauA could be mitigated by adding reducing agents, such as DTT and β-ME. Furthermore, the FDA-approval drug auranofin, a TXNRD1 inhibitor, triggered oligomerization of the cytoskeletal protein Talin-1 in AGS cells, indicating that inhibiting TXNRD1 triggered disulfide stress. In conclusion, this study uncovered GlauA as an efficient inhibitor of TXNRD1 and demonstrated the potential of TXNRD1 inhibition as an effective anticancer strategy by disrupting redox homeostasis and inducing disulfide stress.© 2024 Federation of European Biochemical Societies.