A lysosome-targetable and two-photon fluorescent probe for imaging endogenous β-galactosidase in living ovarian cancer cells

Abstract

The early diagnosis of ovarian cancer plays an important role in the treatment of ovarian cancer. β-Galactosidase (β-gal) which is an overexpressed enzyme in primary ovarian cancer can be employed as a valuable biomarker of ovarian cancer. A fluorescent probe for β-gal detection and imaging is of important significance for the diagnosis of primary ovarian cancer. Toward this goal, we have rationally designed and synthesized a novel two-photon fluorescence probe FC-βgal for monitoring endogenous β-gal in lysosome. The probe FC-βgal showed apparently fluorescence changes from blue to green in response to β-gal by the cleavage of glycosidic bond. 4-Propylmorpholine group endowed the probe with the property of lysosomal targeting. We confirmed that the probe FC-βgal exhibited rapid response, high sensitivity, excellent biocompatibility and favorable performances to β-gal even in the interfering of other biologic substances. In addition, single photon and two-photon confocal imaging experiments indicated that probe FC-βgal displayed a desirable cellular imaging for endogenous β-gal in human ovarian cancer SKOV-3 cells with low cytotoxicity. Moreover, the probe had satisfactory ability to accumulate into lysosomes compared with LysoTracker.