Department of Chemistry, Sookmyung Women's University, Seoul 04310, Korea.
The School of East-West Medical Science, Kyung Hee University, Yongin 17104, Korea.
ACS Appl Bio Mater. 2021 Mar 15;4(3):2052-2057. doi: 10.1021/acsabm.0c01085. Epub 2020 Oct 12.
Aromatic nitro compounds are reduced to their corresponding amino derivatives by nitroreductases (NTR), while identification and characterization of the corresponding enzymes in mammalian systems are yet unrevealed. However, mammalian NTR activity has been considered as a favorable target in development of theranostic agents for cancer and hypoxia of solid tumors. Currently, small molecule-based fluorescent probes have emerged as a valuable assay tool for NTR activity. However, there has been a limit to comparing NTR activity between different cells, since most probes have relied on fluorescence changes that are affected by not only enzymatic activity but also nonenzymatic factors. Here, we developed a self-calibrating bipartite fluorescent probe, consisting of NTR-sensitive nitronaphthalimide and nonsensitive coumarin moieties. Thereby, it was possible to compare the relative NTR activity by monitoring fluorescence ratios in noncancerous and some cancerous cells and to demonstrate for certain that the elevated NTR activity is associated with cancer cells and hypoxia states.
芳香族硝基化合物可被硝基还原酶（NTR）还原为相应的氨基衍生物，而哺乳动物系统中相应酶的鉴定和特性尚不清楚。然而，哺乳动物 NTR 活性已被认为是开发癌症和实体瘤缺氧治疗诊断试剂的有利靶点。目前，基于小分子的荧光探针已成为 NTR 活性的一种有价值的检测工具。然而，由于大多数探针依赖于荧光变化，这些变化不仅受酶活性的影响，还受非酶因素的影响，因此很难在不同细胞之间比较 NTR 活性。在这里，我们开发了一种自校准的双分体荧光探针，由 NTR 敏感的硝基萘酰亚胺和非敏感的香豆素部分组成。通过监测非癌细胞和一些癌细胞中的荧光比值，可以比较相对 NTR 活性，并证明升高的 NTR 活性与癌细胞和缺氧状态有关。
