Department of Chemistry, National University of Singapore, Singapore 117543.
J Am Chem Soc. 2010 Jan 20;132(2):656-66. doi: 10.1021/ja907716f.
Orlistat, or tetrahydrolipstatin (THL), is an FDA-approved antiobesity drug with potential antitumor activities. Cellular off-targets and potential side effects of Orlistat in cancer therapies, however, have not been extensively explored thus far. In this study, we report the total of synthesis of THL-like protein-reactive probes, in which extremely conservative modifications (i.e., an alkyne handle) were introduced in the parental THL structure to maintain the native biological properties of Orlistat, while providing the necessary functionality for target identification via the bio-orthogonal click chemistry. With these natural productlike, cell-permeable probes, we were able to demonstrate, for the first time, this chemical proteomic approach is suitable for the identification of previously unknown cellular targets of Orlistat. In addition to the expected fatty acid synthase (FAS), we identified a total of eight new targets, some of which were further validated by experiments including Western blotting, recombinant protein expression, and site-directed mutagenesis. Our findings have important implications in the consideration of Orlistat as a potential anticancer drug at its early stages of development for cancer therapy. Our strategy should be broadly useful for off-target identification against quite a number of existing drugs and/or candidates, which are also covalent modifiers of their biological targets.
奥利司他，又称四氢脂抑素（THL），是一种获得美国食品药品监督管理局（FDA）批准的抗肥胖药物，具有潜在的抗肿瘤活性。然而，奥利司他在癌症治疗中的细胞非靶标和潜在副作用迄今尚未得到广泛研究。在这项研究中，我们报告了 THL 类似蛋白反应性探针的全合成，其中在母体 THL 结构中引入了极其保守的修饰（即炔烃手柄），以保持奥利司他的天然生物学特性，同时提供通过生物正交点击化学进行靶标识别的必要功能。利用这些类似天然产物、细胞渗透性探针，我们首次证明了这种化学蛋白质组学方法适用于鉴定以前未知的奥利司他细胞靶标。除了预期的脂肪酸合酶（FAS）之外，我们总共鉴定了 8 个新靶标，其中一些靶标通过包括 Western blot、重组蛋白表达和定点突变在内的实验进一步验证。我们的研究结果在考虑将奥利司他作为一种潜在的抗癌药物用于癌症治疗的早期阶段具有重要意义。我们的策略应该对相当数量的现有药物和/或候选药物具有广泛的适用性，这些药物也是其生物靶标的共价修饰剂。
