作者:Nicolas Garnier、Geneviève G. J. Redstone、Michael S. Dahabieh、Jessica N. Nichol、Sonia V. del Rincon、Yuxuan Gu、D. Scott Bohle、Yan Sun、Douglas S. Conklin、Koren K. Mann、Wilson H. Miller
DOI:10.1124/mol.113.089433
日期:2014.4
Darinaparsin (Dar; ZIO-101; S -dimethylarsino-glutathione) is a promising novel organic arsenical currently undergoing clinical studies in various malignancies. Dar consists of dimethylarsenic conjugated to glutathione (GSH). Dar induces more intracellular arsenic accumulation and more cell death than the FDA-approved arsenic trioxide (ATO) in vitro, but exhibits less systemic toxicity. Here, we propose a mechanism for Dar import that might explain these characteristics. Structural analysis of Dar suggests a putative breakdown product: dimethylarsino-cysteine (DMAC). We show that DMAC is very similar to Dar in terms of intracellular accumulation of arsenic, cell cycle arrest, and cell death. We found that inhibition of γ -glutamyl-transpeptidase ( γ -GT) protects human acute promyelocytic leukemia cells (NB4) from Dar, but not from DMAC, suggesting a role for γ -GT in the processing of Dar. Overall, our data support a model where Dar, a GSH S -conjugate, is processed at the cell surface by γ -GT, leading to formation of DMAC, which is imported via xCT, xAG, or potentially other cystine/cysteine importing systems. Further, we propose that Dar induces its own import via increased xCT expression. These mechanisms may explain the enhanced toxicity of Dar toward cancer cells compared with ATO.
Darinaparsin(Dar;ZIO-101;S-二甲基胂-谷胱甘肽)是一种前景广阔的新型有机砷化物,目前正在对各种恶性肿瘤进行临床研究。Dar由与谷胱甘肽(GSH)共轭的二甲基胂组成。与美国食品与药物管理局批准的三氧化二砷(ATO)相比,Dar 在体外诱导细胞内砷积累的程度更高,细胞死亡的数量更多,但其全身毒性较低。在这里,我们提出了一种可以解释这些特性的 Dar 导入机制。Dar 的结构分析表明了一种可能的分解产物:二甲基砷-半胱氨酸(DMAC)。我们发现 DMAC 在砷的细胞内积累、细胞周期停滞和细胞死亡方面与 Dar 非常相似。我们发现,抑制γ-谷氨酰转肽酶(γ -GT)能保护人类急性早幼粒细胞白血病细胞(NB4)免受Dar的伤害,但不能保护其免受DMAC的伤害,这表明γ -GT在Dar的处理过程中发挥作用。总之,我们的数据支持这样一个模型:Dar 是一种 GSH S - 共轭物,在细胞表面由 γ -GT 处理,形成 DMAC,DMAC 通过 xCT、xAG 或其他潜在的胱氨酸/半胱氨酸输入系统输入。此外,我们还提出,Dar 可通过增加 xCT 的表达来诱导其自身的输入。与 ATO 相比,这些机制可能是 Dar 对癌细胞毒性增强的原因。