Potent Trypanocidal Curcumin Analogs Bearing a Monoenone Linker Motif Act on <i>Trypanosoma brucei</i> by Forming an Adduct with Trypanothione
作者:Abdulsalam A.M. Alkhaldi、Darren J. Creek、Hasan Ibrahim、Dong-Hyun Kim、Neils B. Quashie、Karl E. Burgess、Chatchawan Changtam、Michael P. Barrett、Apichart Suksamrarn、Harry P. de Koning
DOI:10.1124/mol.114.096016
日期:2015.3
We have previously reported that curcumin analogs with a C7 linker bearing a C4-C5 olefinic linker with a single keto group at C3 (enone linker) display midnanomolar activity against the bloodstream form of Trypanosoma brucei . However, no clear indication of their mechanism of action or superior antiparasitic activity relative to analogs with the original di-ketone curcumin linker was apparent. To further investigate their utility as antiparasitic agents, we compare the cellular effects of curcumin and the enone linker lead compound 1,7-bis(4-hydroxy-3-methoxyphenyl)hept-4-en-3-one (AS-HK014) here. An AS-HK014–resitant line, trypanosomes adapted to AS-HK014 (TA014), was developed by in vitro exposure to the drug. Metabolomic analysis revealed that exposure to AS-HK014, but not curcumin, rapidly depleted glutathione and trypanothione in the wild-type line, although almost all other metabolites were unchanged relative to control. In TA014 cells, thiol levels were similar to untreated wild-type cells and not significantly depleted by AS-HK014. Adducts of AS-HK014 with both glutathione and trypanothione were identified in AS-HK014–exposed wild-type cells and reproduced by chemical reaction. However, adduct accumulation in sensitive cells was much lower than in resistant cells. TA014 cells did not exhibit any changes in sequence or protein levels of glutathione synthetase and γ -glutamylcysteine synthetase relative to wild-type cells. We conclude that monoenone curcuminoids have a different mode of action than curcumin, rapidly and specifically depleting thiol levels in trypanosomes by forming an adduct. This adduct may ultimately be responsible for the highly potent trypanocidal and antiparasitic activity of the monoenone curcuminoids.
我们以前曾报道过,姜黄素类似物的 C7 连接体带有一个 C4-C5 烯烃连接体,C3 处有一个酮基(烯酮连接体),对血液中的布氏锥虫具有中南摩尔活性。然而,与带有原始二酮姜黄素连接体的类似物相比,它们的作用机制或更优越的抗寄生虫活性并没有明显的迹象。为了进一步研究它们作为抗寄生虫药物的效用,我们比较了姜黄素和烯酮连接体先导化合物 1,7-双(4-羟基-3-甲氧基苯基)庚-4-烯-3-酮(AS-HK014)对细胞的作用。通过体外接触 AS-HK014,培育出了抗 AS-HK014 的品系,即适应 AS-HK014 的锥虫(TA014)。代谢组学分析表明,暴露于 AS-HK014 而不是姜黄素会迅速消耗野生型品系中的谷胱甘肽和胰硫素,但几乎所有其他代谢物与对照组相比都没有变化。在 TA014 细胞中,硫醇水平与未经处理的野生型细胞相似,并没有被 AS-HK014 显著消耗。在暴露于 AS-HK014 的野生型细胞中发现了 AS-HK014 与谷胱甘肽和胰硫蛋白的加合物,并通过化学反应进行了再现。不过,敏感细胞中的加合物积累远低于抗性细胞。与野生型细胞相比,TA014 细胞中谷胱甘肽合成酶和 γ -谷氨酰半胱氨酸合成酶的序列或蛋白质水平没有发生任何变化。我们的结论是,单烯酮类姜黄素的作用模式与姜黄素不同,它能通过形成一种加合物,快速、特异性地消耗锥虫体内的硫醇水平。这种加合物可能是单烯酮类姜黄素具有高效杀锥虫和抗寄生虫活性的最终原因。