ABSTRACT Elucidating the intricate relationships between metabolic and transport pathways contributes to improved predictions of in vivo drug disposition and drug-drug interactions. Here we reported that inhibited excretion of conjugative metabolites [i.e., hesperetin 39-O-sulfate (H39S) and hesperetin 7-O-sulfate (H7S)] by MK-571 led to reduced metabolism of hesperetin (a maximal 78% reduction) in human embryonic kidney 293 cells overexpressing sulfotransferase 1A3 (named SULT293 cells). The strong dependence of cellular sulfonation on the efflux transport of generated sulfated metabolites revealed an interplay of sulfonation metabolism with efflux transport (or sulfonation-transport interplay). Polymerase chain reaction (PCR) and Western blot analyses demonstrated that SULT293 cells expressed multiple sulfatases such as arylsulfatase A (ARSA), ARSB, and ARSC. Of these three desulfonation enzymes, only ARSB showed significant activities toward hesperetin sulfates. The intrinsic clearance values for the hydrolysis of H39S and H7S were estimated at 0.6 and 0.5 ml/h/mg, respectively. Furthermore, knockdown of ARSB attenuated the regulatory effect of efflux transporter on cellular sulfonation, whereas overexpression of ABSB enhanced the transporter effect. Taken together, the results indicated that ARSB mediated the sulfonation-transport interplay in SULT293 cells
