Metabolism of cisplatin to a nephrotoxin in proximal tubule cells
Metabolism of cisplatin to a nephrotoxin in proximal tubule cells
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DOI：
10.1097/01.asn.0000042803.28024.92
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发表时间：
2003-01-01
影响因子：
13.6
通讯作者：
Hanigan, MH
中科院分区：
文献类型：
--
作者：
Townsend, DM;Deng, M;Hanigan, MH
顺铂是一种常用的化疗药物，具有肾毒性。顺铂选择性杀死近曲小管细胞的机制迄今为止尚不清楚。最近对小鼠和大鼠的研究表明，阿西维星或（氨氧基）乙酸可以阻断顺铂的肾毒性，这两种酶抑制剂可以阻断一系列肾毒性卤化烯烃的代谢激活。在这项研究中，假设顺铂在肾脏中被激活为有毒代谢物，其途径与已被证明激活卤代烯烃的途径相同。这种激活始于谷胱甘肽缀合物的形成，谷胱甘肽缀合物代谢为半胱氨酰-甘氨酸缀合物、半胱氨酸缀合物，最后代谢为反应性硫醇。在本研究中，开发了一种方案，其中将 LLC-PK1 细胞的汇合单层暴露于临床相关浓度的顺铂或顺铂缀合物 3 小时。 72小时时测定细胞活力。研究了γ-谷氨酰转肽酶（GGT）和半胱氨酸-S-缀合物β-裂合酶在每种顺铂缀合物的代谢中的作用。将顺铂与谷胱甘肽、半胱氨酰-甘氨酸或 N-乙酰基-半胱氨酸预孵育以允许顺铂缀合物自发形成，增加了顺铂对 LLC-PK1 细胞的毒性。 GGT 活性的抑制表明 GGT 仅对于顺铂-谷胱甘肽-缀合物的毒性是必需的。半胱氨酸-S-缀合物β-裂合酶的抑制降低了每种顺铂缀合物的毒性。这些数据表明顺铂在近曲小管细胞中的代谢是其肾毒性所必需的。该途径的阐明为抑制顺铂肾毒性提供了新的靶点。
Cisplatin, a commonly used chemotherapeutic agent, is nephrotoxic. The mechanism by which cisplatin selectively kills the proximal tubule cells was heretofore unknown. Recent studies in mice and rats have shown that the nephrotoxicity of cisplatin can be blocked by acivicin or (aminooxy)acetic acid, the same enzyme inhibitors that block the metabolic activation of a series of nephrotoxic halogenated alkenes. In this study, it was hypothesized that cisplatin is activated in the kidney to a toxic metabolite through the same pathway that has been shown to activate the halogenated alkenes. This activation begins with the formation of a glutathione-conjugate that is metabolized to a cysteinyl-glycine-conjugate, to a cysteine-conjugate, and finally to a reactive thiol. In this study, a protocol was developed in which confluent monolayers of LLC-PK1 cells were exposed to clinically relevant concentrations of cisplatin or cisplatin-conjugate for 3 h. Cell viability was assayed at 72 h. The role of gamma-glutamyl transpeptidase (GGT) and cysteine-S-conjugate beta-lyase in the metabolism of each of the cisplatin-conjugates was investigated. Pre-incubation of cisplatin with glutathione, cysteinyl-glycine, or N-acetyl-cysteine to allow for the spontaneous formation of cisplatin-conjugates increased the toxicity of cisplatin toward LLC-PK1 cells. Inhibition of GGT activity showed that GGT was necessary only for the toxicity of the cisplatin-glutathione-conjugate. Inhibition of cysteine-S-conjugate beta-lyase reduced the toxicity of each of the cisplatin-conjugates. These data demonstrate that metabolism of cisplatin in proximal tubule cells is required for its nephrotoxicity. The elucidation of this pathway provides new targets for the inhibition of cisplatin nephrotoxicity.