Analysis of the inhibition of mammalian thioredoxin, thioredoxin reductase, and glutaredoxin by cis-diamminedichloroplatinum (II) and its major metabolite, the glutathione-platinum complex
Analysis of the inhibition of mammalian thioredoxin, thioredoxin reductase, and glutaredoxin by cis-diamminedichloroplatinum (II) and its major metabolite, the glutathione-platinum complex
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DOI：
10.1016/s0891-5849(01)00698-0
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发表时间：
2001-11-15
影响因子：
7.4
通讯作者：
Spyrou, G
中科院分区：
文献类型：
--
作者：
Arnér, ESJ;Nakamura, H;Spyrou, G
多项研究表明，顺式二氯二氨铂 (II)（顺铂，CDDP）的细胞毒性与抑制硫氧还蛋白系统（即硫氧还蛋白 (Trx)、硫氧还蛋白还原酶 (TrxR) 和 NADPH）的细胞内活性之间存在相关性。相反，Trx 系统的细胞活性增加会导致对 CDDP 的耐药性。在本研究中，我们分析了 CDDP 与 Trx 和 TrxR 的相互作用，以阐明其机制。 CDDP 对 NADPH 还原（但未氧化）的 TrxR 的时间依赖性动力学抑制是不可逆的，强烈表明还原的含硒代半胱氨酸活性位点的共价修饰。假设二级动力学，CDDP 抑制 TrxR 的速率常数为 21 +/- 3 M(-1)s(-1)。发现转铂是一种更有效的抑制剂，其二阶速率常数为 84 +/- 22 M(-1)s(-1)，而卡铂（高达 1 mM）在相同条件下对该酶没有抑制作用。相比之下，CDDP、转铂或卡铂仅轻微或根本不抑制大肠杆菌 Trx 或人或细菌谷氧还蛋白 (Grx) 活性。然而，我们发现顺铂的纯化谷胱甘肽加合物双-(谷胱甘肽)铂(II)（GS-铂复合物，GS-Pt）可抑制谷氧还蛋白，在人 Grx 的标准 β-羟乙基二硫键偶联测定中，IC50 = 350 muM。 GS-Pt 也以相似的效率抑制哺乳动物 Trx 系统（IC50 = 325 muM），而大肠杆菌 Trx 系统和谷胱甘肽还原酶均未受到抑制。 GS-Pt 的形成是细胞消除 CDDP 的主要途径。 GS-Pt 抑制哺乳动物 Trx 和 Grx 系统的事实表明，CDDP 可能在其代谢的几个阶段发挥作用，包括与 GSH 结合后，这与细胞二硫键/二硫醇氧化还原调节系统密切相关。 (C) 2001 爱思唯尔科学公司。
Several studies have demonstrated a correlation between cellular toxicity of cis-diamminedichloroplatinum (II) (cisplatin, CDDP) and inhibited intracellular activity of the thioredoxin system, i.e,, thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH. Conversely, increased cellular activity of the Trx system confers resistance to CDDP. In this study, we have analyzed the interaction of CDDP with Trx and TrxR in order to clarify the mechanism. The inhibition with time-dependent kinetics by CDDP of NADPH-reduced (but not oxidized) TrxR was irreversible, strongly suggesting covalent modification of the reduced selenocysteine-containing active site. Assuming second order kinetics, the rate constant of TrxR inhibition by CDDP was 21 +/- 3 M(-1)s(-1). Transplatin was found to be an even more efficient inhibitor, with a second order rate constant of 84 +/- 22 M(-1)s(-1), whereas carboplatin (up to 1 mM) gave no inhibition of the enzyme under the same conditions. Escherichia coli Trx or human or bacterial glutaredoxin (Grx) activities were in comparison only slightly or not at all inhibited by either CDDP, transplatin, or carboplatin. However, glutaredoxins were found to be inhibited by the purified glutathione adduct of cisplatin, bis-(glutathionato)platiniim(II) (GS-Platinum complex, GS-Pt), with an IC50 = 350 muM in the standard beta -hydroxyethyl disulfide-coupled assay for human Grx. Also the mammalian Trx system was inhibited by GS-Pt with similar efficiency (IC50 = 325 muM), whereas neither the E. coli Trx system nor glutathione reductase were inhibited. Formation of GS-Pt is a major route for cellular elimination of CDDP. The fact that GS-Pt inhibits the mammalian Trx as well as Grx systems shows that CDDP may exert effects at several stages of its metabolism, including after conjugation with GSH, which are intimately linked with the cellular disulfide/dithiol redox regulatory systems. (C) 2001 Elsevier Science Inc.