An Activity-Based Fluorogenic Probe Enables Cellular and in Vivo Profiling of Carboxylesterase Isozymes
作者:Shi-Yu Liu、Ren-Yu Qu、Rong-Rong Li、Yao-Chao Yan、Yao Sun、Wen-Chao Yang、Guang-Fu Yang
DOI:10.1021/acs.analchem.0c01554
日期:2020.7.7
Carboxylesterases (CEs) exist as multiple types of isomers in humans, and two major types are CE1 and CE2. They are widely distributed in human tissues and well-known for their important roles in drug metabolism and pathology of various diseases. Thus, the detection of CEs in living systems could provide efficient proof in disease diagnostics, as well as important information regarding chemotherapeutic effects of antitumor drugs and prognosis. To develop a specific probe to discriminate CEs from other hydrolases, especially cholinesterases, is quite challenging due to their structural similarities and substrate specificity. To date, almost all of the fluorescent probes developed for CEs have been constructed with an acetyl group as the recognition unit. Herein we proposed a new design strategy of probe–cavity matching, which led to the identification of a new fluorogenic substrate (termed as HBT-CE) with high specificity toward both CE isomers and improved sensitivity, considering the higher binding affinity and catalysis efficiency. The promising capability of HBT-CE was further demonstrated for endogenous CEs imaging in living cells, zebrafish, and nude mice. In addition, HBT-CE was successfully applied in kinetically monitoring drug-induced CE regulation in cancer cells. All of these findings suggest that HBT-CE is a valuable tool for tracking and imaging endogenous CEs in complex biological systems.
羧酯酶(CE)在人体内以多种异构体形式存在,其中最主要的两种是CE1和CE2。它们广泛分布于人体组织中,在药物代谢和各种疾病的病理学中发挥着重要作用。因此,在活体系统中检测CE可以为疾病诊断提供有效证据,以及抗肿瘤药物化疗效果和预后等重要信息。由于CE与其他水解酶(尤其是胆碱酯酶)在结构上相似且底物特异性不同,因此开发一种能够区分它们的特异性探针极具挑战性。迄今为止,几乎所有针对CE开发的荧光探针都是以乙酰基作为识别单元构建的。在此,我们提出了一种新的探针-空腔匹配设计策略,该策略可识别一种对CE异构体具有高特异性的新型荧光底物(称为HBT-CE),并提高灵敏度,同时考虑到更高的结合亲和力和催化效率。HBT-CE在活细胞、斑马鱼和裸鼠体内成像中表现出良好的前景。此外,HBT-CE还成功应用于动力学监测药物诱导的癌细胞中CE的调节。所有这些发现表明,HBT-CE是追踪和成像复杂生物系统中内源性CE的有价值的工具。