The roles of breast cancer resistance protein (BCRP/ABCG2) and multidrug resistance-associated proteins (MRPs/ABCCs) in the excretion of cycloicaritin-3-O-glucoronide in UGT1A1-overexpressing HeLa cells

Abstract

Cycloicaritin is a bioactive natural phenolic compound from Epimedium species. However, the glucuronidation and excretion which would influence oral bioavailability and pharmacokinetics of cycloicaritin still remain unknown. Here we aimed to establish UGT1A1 stably transfected HeLa cells, and to determine the contributions of BCRP and MRPs transporters to excretion of cycloicaritin-3-O-glucuronide. First, β-estradiol was used to validate the expression of active UGT1A1 protein in engineered HeLa1A1 cells. Furthermore, Ko143 (5 and 20 μM) led to a significant decrease (42.4%-63.8%, p < 0.01) in CICT-3-G excretion and obvious accumulation (19.7%-54.2%, p < 0.05) of intracellular CICT-3-G, while MK571 (5 and 20 μM) caused a significant reduction (46.8%-64.8%, p < 0.05) in the excretion and obvious elevation (50.7%-85.2%, p < 0.01) of intracellular level of CICT-3-G. Furthermore, BCRP knocked-down brought marked reduction in excretion rates of CICT-3-G (26.0%-42.2%, p < 0.01), whereas MRP1 and MRP4-mediated silencing led to significant decrease in the excretion of CICT-3-G (23.8%-35.4%, p < 0.05 for MRP1 and 11.9%-16.0%, p < 0.05 for MRP4). By contrast, neither CICT-3-G excretion nor CICT-3-G accumulation altered in MRP3 knocked-down cells as compared to scramble cells. Taken together, BCRP, MRP1 and MRP4 were identified as the most important contributors for CICT-3-G excretion. Meanwhile, the UGT1A1 modified HeLa cells were a simple and practical tool to study UGT1A1-mediated glucuronidation and to characterize BCRP and MRPs-mediated glucuronide transport at a cellular level.

PI3K/AKT pathway as a key link modulates the multidrug resistance of cancers

“…MRP1 is primarily expressed in physiological disorders, such as the blood-brain barrier and may limit drug uptake and retention 110 . Activation of the PI3K/AKT pathway promotes via MDR by regulation of the expression of a variety of cellular processes, including apoptosis (Bax/Bcl-2) and drug transport (MRP1) 111 , where nuclear factor erythroid-derived 2 (Nrf2) is a nuclear regulator of MRP1, and it is part of the reason for MDR.…”

Characterization of metabolic activity, isozyme contribution and species differences of bavachin, and identification of efflux transporters for bavachin-O-glucuronide in HeLa1A1 cells

“…The maximal clearance (CL max ) for Hill equation model was obtained using equation (5). [23] The CL int values for two-site kinetics were the V max /K m of low-affinity enzyme (i.e., V max2 /K m2 ). [28] V ¼…”

Potential metabolism determinants and drug–drug interactions of a natural flavanone bavachinin

“…This was consistent with our previous reports in which BCRP and MRP4 participated in excretion of conjugated glucuronides of several prenylated avonoids (or avanones). 21,22,25,41 Another data showed that when the function of BCRP or MRP4 transporters was inhibited, signicant down-regulation of cellular glucuronidation of bavachinin in HeLa1A1 cells was observed (Fig. 3e).…”

“…43 A remarkable limitation is the unexplained role of MRP2 in excretion of G1 due to the absence of MRP2 transporters in HeLa1A1 cells. [21][22][23]25,41,43 Furthermore, MDCKII-MRP2-UGT1A1 cells could well characterize the glucuronidation by UGT1A1 and glucuronides excretion by MRP2 transporters. 45 In addition, Mrp2 (Abcc2) knock-out mice were usually used to evaluate the roles of Mrp2 according to the pharmacokinetic behaviors.…”

“…21 In our previous works, many glucuronides of natural compounds were the substrates of BCRP or MRPs transporters. [21][22][23][24][25] In addition, the glucuronidation activity would be altered when the function of BCRP or MRPs transporters were inhibited due to the presence of "glucuronidationtransport interplay". 21 However, the effects of BCRP and MRPs transporters on the metabolism and disposition of bavachinin still remains unknown.…”