Department of Cell Biology, Dalian Medical University, China.
Biochem Pharmacol. 2010 May 15;79(10):1516-25. doi: 10.1016/j.bcp.2010.01.022. Epub 2010 Jan 25.
Cancer preventive reagent trans-resveratrol is intracellularly biotransformed to different metabolites. However, it is still unclear whether trans-resveratrol exerts its biological effects directly or through its metabolite(s). This issue was addressed here by identifying the metabolic pattern and the bioactive form of resveratrol in a resveratrol-sensitive human medulloblastoma cell line, UW228-3. The cell lysates and condition media of UW228-3 cells with or without 100 microM resveratrol treatment were analyzed by HPLC and LC/MS which revealed (1) that resveratrol was chemically unstable and the spontaneous generation of cis-resveratrol reduced resveratrol's anti-medulloblastoma efficacy and (2) that resveratrol monosulfate was the major metabolite of the cells. To identify the bioactive form of resveratrol, a mixture-containing approximately half fraction of resveratrol monosulfate was prepared by incubating trans-resveratrol with freshly prepared rat brain lysates. Medulloblastoma cells treated by 100 microM of this mixture showed attenuated cell crisis. The overall levels of the three brain-associated sulfotransferases (SULT1A1, 1C2 and 4A1) were low in medulloblastoma cells in vivo and in vitro in comparison with that in human noncancerous and rat normal cerebella; resveratrol could more or less up-regulate the production of these enzymes in UW228-3 cells but their overall level was still lower than that in normal cerebellum tissue. Our study thus demonstrated for the first time that trans-resveratrol is the bioactive form in medulloblastoma cells in which the expression of brain-associated SULTs was down-regulated, resulting in the increased intracellular bioavailability and anti-medulloblastoma efficacy of trans-resveratrol.
癌症预防试剂白藜芦醇在细胞内被生物转化为不同的代谢物。然而，白藜芦醇是直接发挥生物作用还是通过其代谢物发挥作用仍不清楚。本研究通过鉴定白藜芦醇在对其敏感的人髓母细胞瘤细胞系 UW228-3 中的代谢模式和生物活性形式来解决这一问题。用或不用 100μM 白藜芦醇处理 UW228-3 细胞的细胞裂解液和条件培养基用 HPLC 和 LC/MS 分析，结果显示：（1）白藜芦醇化学性质不稳定，顺式白藜芦醇的自发生成降低了白藜芦醇对髓母细胞瘤的疗效；（2）白藜芦醇单硫酸盐是细胞的主要代谢物。为了鉴定白藜芦醇的生物活性形式，通过用新鲜制备的大鼠脑裂解物孵育白藜芦醇混合物，制备了约一半白藜芦醇单硫酸盐的混合物。用 100μM 该混合物处理的髓母细胞瘤细胞显示出细胞危机减弱。与非癌性人类和正常大鼠小脑相比，体内和体外的髓母细胞瘤细胞中三种与脑相关的磺基转移酶（SULT1A1、1C2 和 4A1）的总水平较低；白藜芦醇或多或少能上调 UW228-3 细胞中这些酶的产生，但它们的总水平仍低于正常小脑组织。因此，我们的研究首次证明，在脑相关 SULT 表达下调的髓母细胞瘤细胞中，反式白藜芦醇是生物活性形式，导致反式白藜芦醇的细胞内生物利用度和抗髓母细胞瘤功效增加。
