Cysteine-Conjugated Metabolite of Ginger Component [6]-Shogaol Serves as a Carrier of [6]-Shogaol in Cancer Cells and in Mice
Cysteine-Conjugated Metabolite of Ginger Component [6]-Shogaol Serves as a Carrier of [6]-Shogaol in Cancer Cells and in Mice
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DOI：
10.1021/tx4001286
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发表时间：
2013-06-01
影响因子：
4.1
通讯作者：
Sang, Shengmin
中科院分区：
文献类型：
--
作者：
Chen, Huadong;Soroka, Dominique N.;Sang, Shengmin
干姜（Zingiber officinale）中的一系列主要成分Shogaols显示出很高的抗癌功效。此前，我们报道了巯基酸途径产生的主要代谢物s -半胱氨酸-[6]-shogaol （M2）对癌细胞的生长抑制作用与[6]shogaol （6S）相当。在这里，我们探讨了M2发挥其生物活性的机制。我们利用一系列的化学稳定性试验结合生物测定表明，巯基缀合物通过作为生姜活性成分6S的载体显示出化学预防效力。在37℃pH值为7.4的环境下，M2被化学降解为6S。M2在癌细胞HCT-116和H-1299中的代谢谱与6S相似，表明其生物转化途径是通过解偶联启动的。此外，过量谷胱甘肽的存在显著延缓了6S和M2的代谢，抵消了6S和M2诱导的细胞死亡，这表明外源增加的有效游离硫醇既促进了5-谷胱甘肽-[6]-shogaol （M13）的形成，又抑制了M2解结产生的游离6S，导致6S进入细胞和生物活性延迟。鉴于M2的化学预防作用和我们在体外的观察，我们研究了其在小鼠体内的代谢。M2和6S在小鼠尿液和粪便样品中表现出相似的代谢谱。六种新的硫醇结合代谢物（M16-M21），以及先前报道的代谢物；液相色谱/质谱法鉴定。特别是M2处理后小鼠粪便中5- n -乙酰半胱氨酸-[6]-shogaol （MS）及其3'-去甲基化产物（M16）丰度的增加，表明M2除了作为6S的载体外，还直接乙酰化为MS， MS在体内进一步去甲基化为M16。综上所述，[6]-shogaol M2的半胱氨酸结合代谢物在癌细胞和小鼠体内作为6S的载体发挥其生物活性。
Shogaols, a series of major constituents in dried ginger (Zingiber officinale), show high anticancer potencies. Previously, we reported that a major metabolite resulting from the mercapturic acid pathway, S-cysteinyl-[6]-shogaol (M2), showed comparable growth inhibitory effects toward cancer cells to [6]shogaol (6S). Here, we probe the mechanism by which M2 exerts its bioactivity. We utilized a series of chemical stability tests in conjunction with bioassays to show that thiol-conjugates display chemopreventative potency by acting as carriers of active ginger component 6S. M2 chemical degradation to 6S was observed in an environment most resembling physiological conditions, with a pH of 7.4 at 37 degrees C. The metabolic profiles of M2 in cancer cells HCT-116 and H-1299 resembled those of 6S, indicating that its biotransformation route was initiated by deconjugation. Further, the presence of excess glutathione significantly delayed 6S and M2 metabolism and counteracted cell death induced by 6S and M2, suggesting that increasing available free thiols exogenously both promoted the formation of 5-glutathionyl-[6]-shogaol (M13) and inhibited the production of free 6S from M2 deconjugation, resulting in delayed 6S cell entry and bioactivity. Given the chemopreventative properties of M2 and our observations in vitro, we investigated its metabolism in mice. M2 and 6S showed similar metabolic profiles in mouse urine and fecal samples. Six new thiol-conjugated metabolites (M16-M21), together with previously reported ones; were identified by LC/MS. In particular, the increase of 5-N-acetylcystenyl-[6]-shogaol (MS) and its 3'-demethylated product (M16) abundance in mouse feces after treatment with M2 indicates that in addition to acting as a carrier of 6S, M2 is also directly acetylated to MS, which is further demethylated to M16 in vivo. In conclusion, the cysteine-conjugated metabolite of [6]-shogaol M2 exerts its bioactivity by acting as a carrier of 6S in both cancer cells and in mice.