Collaborative modification strategy to develop a highly selective fluorescent probe for human UDP-glucuronosyltransferase 1A10

[Display omitted] •We developed the first “off–on” fluorescent probe UPr6 for UGT1A10.•UPr6 has excellent isoform-selectivity and sensitivity.•UPr6 was used to monitor UGT1A10 activity in cells, rat tissues, and zebrafish.•Licorice compounds EUC and DAP were screened as potent UGT1A10 inhibitors.•EUC and DAP could improve sensitivity of CPT-11 against resistant cells. UDP-glucuronosyltransferase 1A10 (UGT1A10) is an important phase II human metabolic enzyme. However, few methods are available to facilely monitor the function of UGT1A10 in biological systems. Here we report the first sensitive and selective fluorescent “off–on” UGT1A10 probe substrate UPr6. Using a collaborative modification strategy, we introduced a rigid propyl morpholine group to the amide and a methoxy group next to 4′-phenoxy of the 4-phenyl-1,8-naphthalimide skeleton to obtain UPr6. Visualization methods were established to evaluate the function of UGT1A10 in living cells, rat tissues, and zebrafish. From a Chinese herbal medicine compound library, two natural products EUC and DAP from licorice were discovered as potent UGT1A10 inhibitors, which remarkably improved the sensitivity of CPT-11 against a resistant human cancer cell line. This work established a feasible strategy to rationally design isoform-specific UGT probe substrates.