Developing a Novel Fluorescent Probe for Selectively Recognizing NQO1 in Cancer Cells and at the Tail Amputation Site of Zebrafish.

NAD(P)H:quinone oxidoreductase 1 (NQO1) is an oxidoreductase that is overexpressed in various types of solid tumor cells and serves as a promising biomarker for cancer. Fluorescence detection of NQO1 is of great significance for the early screening of certain malignancies. Herein, a reaction probe (PACN) for selectively recognizing NQO1 was developed by hybridizing coumarin analogues modified with benzothiazole as the fluorescent reporter and a trimethyl-locked quinone propionic acid as the NQO1 specific recognition unit. The probe PACN demonstrated high selectivity and sensitivity in the specific recognition of NQO1, with a low detection limit of 2.68 ng/mL. Moreover, a significant turn-on fluorescent signal can be observed at 525 nm upon reaction with NQO1. Furthermore, PACN can specifically detect NQO1 in cancer cells (A549 cells) rather than in normal cells (BEAS-2B cells). Notably, an inflammation model was established using tail-damaged zebrafish to induce the expression of NQO1, and PACN was successfully used to image NQO1 in the wound area of the tail-damaged zebrafish. Meanwhile, the design of PACN provides important information for the early diagnosis of cancer and also offers certain guidance for the development of fluorescent probes specifically for detecting NQO1.