Skip to main content
Advertisement

Main menu

  • Home
  • Articles
    • Current Issue
    • Fast Forward
    • Latest Articles
    • Archive
  • Information
    • Instructions to Authors
    • Submit a Manuscript
    • FAQs
    • For Subscribers
    • Terms & Conditions of Use
    • Permissions
  • Editorial Board
  • Alerts
    • Alerts
    • RSS Feeds
  • Virtual Issues
  • Feedback
  • Other Publications
    • Drug Metabolism and Disposition
    • Journal of Pharmacology and Experimental Therapeutics
    • Molecular Pharmacology
    • Pharmacological Reviews
    • Pharmacology Research & Perspectives
    • ASPET

User menu

  • My alerts
  • Log in
  • My Cart

Search

  • Advanced search
Journal of Pharmacology and Experimental Therapeutics
  • Other Publications
    • Drug Metabolism and Disposition
    • Journal of Pharmacology and Experimental Therapeutics
    • Molecular Pharmacology
    • Pharmacological Reviews
    • Pharmacology Research & Perspectives
    • ASPET
  • My alerts
  • Log in
  • My Cart
Journal of Pharmacology and Experimental Therapeutics

Advanced Search

  • Home
  • Articles
    • Current Issue
    • Fast Forward
    • Latest Articles
    • Archive
  • Information
    • Instructions to Authors
    • Submit a Manuscript
    • FAQs
    • For Subscribers
    • Terms & Conditions of Use
    • Permissions
  • Editorial Board
  • Alerts
    • Alerts
    • RSS Feeds
  • Virtual Issues
  • Feedback
  • Visit jpet on Facebook
  • Follow jpet on Twitter
  • Follow jpet on LinkedIn
Research ArticleMetabolism, Transport, and Pharmacogenomics

Genetic and Dietary Regulation of Glyburide Efflux by the Human Placental Breast Cancer Resistance Protein Transporter

Kristin M. Bircsak, Vivek Gupta, Poi Yu Sofia Yuen, Ludwik Gorczyca, Barry I. Weinberger, Anna M. Vetrano and Lauren M. Aleksunes
Journal of Pharmacology and Experimental Therapeutics April 2016, 357 (1) 103-113; DOI: https://doi.org/10.1124/jpet.115.230185
Kristin M. Bircsak
Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy (K.M.B., L.M.A., L.G.), and Environmental and Occupational Health Sciences Institute, Rutgers, The State University of New Jersey (L.M.A.), Piscataway, New Jersey; Departments of Obstetrics and Gynecology (V.G.) and Pediatrics (P.Y.S.Y., A.M.V.), Rutgers University Robert Wood Johnson Medical School, New Brunswick, New Jersey; Hofstra North Shore-LIJ School of Medicine, Cohen Children’s Medical Center of New York, New Hyde Park, New York (B.I.W.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Vivek Gupta
Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy (K.M.B., L.M.A., L.G.), and Environmental and Occupational Health Sciences Institute, Rutgers, The State University of New Jersey (L.M.A.), Piscataway, New Jersey; Departments of Obstetrics and Gynecology (V.G.) and Pediatrics (P.Y.S.Y., A.M.V.), Rutgers University Robert Wood Johnson Medical School, New Brunswick, New Jersey; Hofstra North Shore-LIJ School of Medicine, Cohen Children’s Medical Center of New York, New Hyde Park, New York (B.I.W.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Poi Yu Sofia Yuen
Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy (K.M.B., L.M.A., L.G.), and Environmental and Occupational Health Sciences Institute, Rutgers, The State University of New Jersey (L.M.A.), Piscataway, New Jersey; Departments of Obstetrics and Gynecology (V.G.) and Pediatrics (P.Y.S.Y., A.M.V.), Rutgers University Robert Wood Johnson Medical School, New Brunswick, New Jersey; Hofstra North Shore-LIJ School of Medicine, Cohen Children’s Medical Center of New York, New Hyde Park, New York (B.I.W.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Ludwik Gorczyca
Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy (K.M.B., L.M.A., L.G.), and Environmental and Occupational Health Sciences Institute, Rutgers, The State University of New Jersey (L.M.A.), Piscataway, New Jersey; Departments of Obstetrics and Gynecology (V.G.) and Pediatrics (P.Y.S.Y., A.M.V.), Rutgers University Robert Wood Johnson Medical School, New Brunswick, New Jersey; Hofstra North Shore-LIJ School of Medicine, Cohen Children’s Medical Center of New York, New Hyde Park, New York (B.I.W.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Barry I. Weinberger
Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy (K.M.B., L.M.A., L.G.), and Environmental and Occupational Health Sciences Institute, Rutgers, The State University of New Jersey (L.M.A.), Piscataway, New Jersey; Departments of Obstetrics and Gynecology (V.G.) and Pediatrics (P.Y.S.Y., A.M.V.), Rutgers University Robert Wood Johnson Medical School, New Brunswick, New Jersey; Hofstra North Shore-LIJ School of Medicine, Cohen Children’s Medical Center of New York, New Hyde Park, New York (B.I.W.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Anna M. Vetrano
Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy (K.M.B., L.M.A., L.G.), and Environmental and Occupational Health Sciences Institute, Rutgers, The State University of New Jersey (L.M.A.), Piscataway, New Jersey; Departments of Obstetrics and Gynecology (V.G.) and Pediatrics (P.Y.S.Y., A.M.V.), Rutgers University Robert Wood Johnson Medical School, New Brunswick, New Jersey; Hofstra North Shore-LIJ School of Medicine, Cohen Children’s Medical Center of New York, New Hyde Park, New York (B.I.W.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Lauren M. Aleksunes
Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy (K.M.B., L.M.A., L.G.), and Environmental and Occupational Health Sciences Institute, Rutgers, The State University of New Jersey (L.M.A.), Piscataway, New Jersey; Departments of Obstetrics and Gynecology (V.G.) and Pediatrics (P.Y.S.Y., A.M.V.), Rutgers University Robert Wood Johnson Medical School, New Brunswick, New Jersey; Hofstra North Shore-LIJ School of Medicine, Cohen Children’s Medical Center of New York, New Hyde Park, New York (B.I.W.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Data
  • Info & Metrics
  • eLetters
  • PDF + SI
  • PDF
Loading

Visual Overview

Figure1
  • Download figure
  • Open in new tab
  • Download powerpoint

Abstract

Glyburide is frequently used to treat gestational diabetes owing to its low fetal accumulation resulting from placental efflux by the breast cancer resistance protein (BCRP)/ABCG2 transporter. Here we sought to determine how exposure to the dietary phytoestrogen genistein and expression of a loss-of-function polymorphism in the ABCG2 gene (C421A) impacted the transport of glyburide by BCRP using stably transfected human embryonic kidney 293 (HEK) cells, human placental choriocarcinoma BeWo cells, and human placental explants. Genistein competitively inhibited the BCRP-mediated transport of 3H-glyburide in both wild-type (WT) and C421A-BCRP HEK-expressing cells, with greater accumulation of 3H-glyburide in cells expressing the C421A variant. In BeWo cells, exposure to genistein for 60 minutes increased the accumulation of 3H-glyburide 30%–70% at concentrations relevant to dietary exposure (IC50 ∼180 nM). Continuous exposure of BeWo cells to genistein for 48 hours reduced the expression of BCRP mRNA and protein by up to 40%, which impaired BCRP transport activity. Pharmacologic antagonism of the estrogen receptor attenuated the genistein-mediated downregulation of BCRP expression, suggesting that phytoestrogens may reduce BCRP levels through this hormone receptor pathway in BeWo cells. Interestingly, genistein treatment for 48 hours did not alter BCRP protein expression in explants dissected from healthy term placentas. These data suggest that whereas genistein can act as a competitive inhibitor of BCRP-mediated transport, its ability to downregulate placental BCRP expression may only occur in choriocarcinoma cells. Overall, this research provides important mechanistic data regarding how the environment (dietary genistein) and a frequent genetic variant (ABCG2, C421A) may alter the maternal-fetal disposition of glyburide.

Introduction

Gestational diabetes (GD) is on the rise worldwide (Dabelea et al., 2005; Ferrara, 2007) and affects 5%–10% of pregnant women in the United States (DeSisto et al., 2014). Glyburide (INN: glibenclamide) is a second-generation sulfonylurea drug used in the treatment of type 2 diabetes and, more recently, GD. In 2000, Langer and colleagues performed a prospective randomized clinical trial that demonstrated the efficacy and safety of glyburide in the treatment of GD compared with insulin (Langer et al., 2000). Furthermore, glyburide was undetectable in cord serum (limit of detection <10 ng/ml), suggesting limited fetal exposure. These findings launched additional investigations (Bertini et al., 2005; Jacobson et al., 2005; Anjalakshi et al., 2007; Ogunyemi et al., 2007) and ultimately resulted in a major shift in the management of GD. By 2011, more than 50% of U.S. obstetricians were prescribing glyburide as first-line pharmacotherapy for GD (Camelo Castillo et al., 2014).

Kraemer et al. (2006) were the first to demonstrate that glyburide is actively removed from the fetal to the maternal circulation, suggesting that transport plays a major role in the transplacental disposition of glyburide (Kraemer et al., 2006). Multiple transporters in the placenta interact with glyburide (Gedeon et al., 2006, 2008a, 2008b; Hemauer et al., 2010), significant evidence points to the breast cancer resistance protein (BCRP/ABCG2) as the major transporter responsible for the active extrusion of glyburide from the placenta. This has been demonstrated using BCRP-overexpressing cells, Bcrp knockout mice, pregnant rats, human placentas, and human placental vesicles (Pollex et al., 2008, 2010; Zhou et al., 2008; Feinshtein et al., 2013).

BCRP is a transmembrane protein that moves xenobiotics and endogenous chemicals out of cells. In the intestine, liver, and kidney, BCRP is expressed on the apical membrane of epithelial cells and promotes the excretion of drugs and chemicals from the body (Maliepaard et al., 2001). In the placenta, BCRP is localized primarily to the apical membrane of syncytiotrophoblasts, where it transports substrates back to the maternal circulation such that fetal exposure to various chemicals including glyburide is restricted (Maliepaard et al., 2001). Although placental BCRP plays a critical role in protecting the fetus from exposure to glyburide, there is limited understanding of the potential consequences of reduced placental BCRP function in pregnant women prescribed glyburide for GD. Infants born to this population of women may be at an elevated risk of neonatal hypoglycemia as a result of fetal glyburide exposure, potentially leading to low birth weight, increased morbidity, and impaired neurologic development (reviewed in Williams, 1997). BCRP function may be compromised by genetic single nucleotide polymorphisms, as well as by environmental factors, including dietary constituents.

A single nucleotide polymorphism occurring at nucleotide 421 (C > A) in the ABCG2 gene leads to an amino acid change from glutamine to lysine (Q141K). In vitro, the C421A genotype is associated with reduced BCRP function (Kondo et al., 2004; Pollex et al., 2010). Importantly, the C421A genotype occurs frequently in Asian (C/A: 30%, A/A: 10%) and Caucasian (C/A: 15%, A/A: 1%) populations (Imai et al., 2002; Zamber et al., 2003; Kobayashi et al., 2005).

Genistein is a soy isoflavone that is found naturally in plants of the Leguminosae family and occurs abundantly in soybeans (U.S. Department of Agriculture, http://www.ars.usda.gov/nutrientdata/isoflav;

United Soybean Board, 2014, http://www.soyconnection.com/sites/default/files/ConsumerAttitudes_Med_062714.pdf).

Considering the increasing consumption of soy-containing products (i.e., tofu, soy formula, dietary supplements) over the last 10 years (United Soybean Board, 2014, http://www.soyconnection.com/sites/default/files/ConsumerAttitudes_Med_062714.pdf), it is important to recognize that components of soy, including genistein, may interfere with the disposition of prescribed drugs. Genistein alone and in combination with other isoflavones has been shown to directly interfere with the BCRP-mediated disposition of drugs in vivo, including BCRP substrates enrofloxacin and nitrofurantoin (Pulido et al., 2006; Merino et al., 2010). Genistein also interacts with proteins that may regulate placental BCRP expression, including the estrogen receptor and the epidermal growth factor receptor (Kuiper et al., 1998; Traxler et al., 1999). Considering this evidence, genistein may reduce placental BCRP function in two distinct manners by: 1) direct inhibition of BCRP activity and 2) altered transcriptional regulation of BCRP.

Because of the increased use of glyburide in GD treatment and the sensitivity of the developing fetus, it is critical to consider separately and together the influence of genetic and environmental factors on the placental BCRP-mediated disposition of glyburide. The purpose of this study was to use complementary in vitro and ex vivo model systems to characterize the molecular mechanisms by which dietary-relevant concentrations of genistein impair the transport of glyburide by BCRP in placental trophoblasts.

Materials and Methods

Chemicals.

Unless otherwise specified, all chemicals were obtained from Sigma-Aldrich (St. Louis, MO).

Cell Culture.

Human embryonic kidney-293 (HEK) cells were stably transfected with an empty vector (EV, pcDNA 3.1), the human wild-type (WT) BCRP/ABCG2 gene, or the human C421A BCRP/ABCG2 variant (kindly provided by Dr. Robert Robey, National Cancer Institute, National Institutes of Health, Bethesda, MD) (Morisaki et al., 2005). Cells were maintained in Dulbecco’s modified Eagle medium (Life Technologies, Carlsbad, CA) with 10% fetal bovine serum (Atlanta Biologicals, Norcross, GA), 1% penicillin-streptomycin (Life Technologies), and 0.2 mg/ml geneticin (Life Technologies) to select for transfected cells. Human placental choriocarcinoma BeWo cells were purchased from American Type Culture Collection (ATCC, Manassas, VA) and grown in phenol-red free Dulbecco’s modified Eagle’s medium: F-12 (Life Technologies) with 10% charcoal-stripped and dextran-treated fetal bovine serum (Atlanta Biologicals) and 1% penicillin-streptomycin (Life Technologies). All cells were maintained at 37°C with 5% CO2 and used in experiments at 80%–90% confluence. For the regulation studies, BeWo cells were incubated with genistein (10 μM) or ICI 182,780 (0–1 μM) for 48 hours, after which they were processed for mRNA, protein, or functional analysis. All chemicals were dissolved in dimethyl sulfoxide (DMSO) such that the final percentage (% v/v) of DMSO did not exceed 0.1% of the treatment media.

Flow Cytometry.

HEK cells overexpressing the EV, WT-BCRP, or C421A-BCRP gene were suspended in cold isotonic PBS with 0.5% bovine serum albumin (BSA), centrifuged (500g, 5 minutes), and washed three times in PBS with 0.5% BSA. Cells in suspension were blocked with human IgG (2 μg/500,000 cells in PBS/0.5% BSA) for 15 minutes at room temperature. Cells were then incubated for 45 minutes at 4°C with the monoclonal phycoerthyrin-labeled anti-BCRP antibody (5D3) or the phycoerthyrin-labeled negative control IgG antibody (R&D Systems, Minneapolis, MN) according to the manufacturer’s protocol. Cells were washed three times (5 minutes with PBS/0.5% BSA) and resuspended in 2% paraformaldehyde/PBS for flow cytometry analysis using a Gallios/FC500 Cytometer with 488-nm wavelength laser excitation (Beckman Coulter, Indianapolis, IN) in the Flow Cytometry/Cell Sorting Core Facility at Rutgers University.

Hoechst 33342 Accumulation Assay.

The BCRP-specific fluorescent substrate, Hoechst 33342, was used to quantify BCRP function in HEK and BeWo cells as previously described (Bircsak et al., 2013). Briefly, HEK and BeWo cells were trypsinized and added to a 96-well plate. After centrifugation (500g, 5 minutes, 5°C) and removal of the media, cells were loaded with Hoechst 33342 (7–15 µM) in the presence or absence of the BCRP-specific inhibitor, Ko143 (1–3000 nM), or the test compound, genistein (0.1–100 µM, for 30 minutes at 37°C and 5% CO2, uptake phase). Cells were washed, centrifuged, and resuspended in substrate-free media with or without inhibitor for 1 hour (efflux phase). During all phases, inhibitor compounds were initially dissolved in DMSO and did not exceed 1% (v/v) of the final treatment media. After the efflux phase, cells were centrifuged, washed, and resuspended in cold PBS for quantification of intracellular fluorescence using the Cellometer Vision automated cell counter (Nexcelom Bioscience, Lawrence, MA). Cell suspension (20 µl) was added to the cell counting chamber, and each sample was analyzed using bright-field images for cell size and cell number. A VB-450-302 filter (excitation/emission: 375/450) allowed for intracellular fluorescence detection of Hoechst 33342. The total number of cells analyzed for each sample ranged from 200 to 2000. In BeWo cells, raw fluorescence intensity for each cell was normalized to cell size.

3H-Glyburide Accumulation Assay.

HEK and BeWo cells were trypsinized and added to a 96-well plate. After centrifugation (500g, 5 minutes, 5°C) and removal of the media, cells were loaded with 3H-glyburide (0.1–10 µM; Specific Activity: 40 µCi; PerkinElmer, Waltham, MA) in the presence and absence of the BCRP-specific inhibitor, Ko143 (1–3000 nM) or the test compound, genistein (0.01–20 µM) for 1 hour at 37°C and 5% CO2. Inhibitors were dissolved in DMSO such that the final concentration of DMSO did not exceed 1% (v/v) in the final treatment media. After the 1-hour incubation, cells were centrifuged, washed, and lysed using 1 M NaOH. Lysates were then neutralized using 1 M HCl and added to 4 ml ScintiSafe Econo 1 liquid scintillation fluid (Fisher Scientific, Waltham, MA) in 7-ml glass liquid scintillation vials (Perkin Elmer). Radioactivity was detected using a TriCarb 2100TR Liquid Scintillation Analyzer (PerkinElmer-Packard, Waltham, MA). A standard curve was used to extrapolate glyburide concentrations. Accumulation of glyburide was normalized to the total protein concentration of cell lysates from representative wells using the bicinchoninic acid (BCA) assay (Pierce Biotechnology, Rockford, IL).

Western Blot.

HEK and BeWo cells were lysed in lysis buffer (20 mM Tris-HCl, 150 mM NaCl, 5 mM EDTA, 1% Triton X-10, and 1% protease inhibitor cocktail). Placenta membrane fractions were prepared as previously described (Memon et al., 2014). Protein concentrations were determined by the BCA assay, and 5–10 μg of total protein was added to SDS-PAGE 4%–12% Bis-Tris gels (Life Technologies), which were resolved by electrophoresis. Transfer of proteins onto polyvinylidene fluoride membranes was completed using an overnight transfer apparatus (BioRad Criterion Blotter; BioRad, Hercules, CA). Membranes were blocked using 5% nonfat milk in 0.5% Tween-20–PBS and then incubated with primary antibodies in 2% nonfat milk in 0.5% Tween-20-PBS for 2 hours. Primary antibodies detected proteins, including BCRP (BXP-53, 1:5000; Enzo Life Sciences, Farmingdale, NY), β-actin (Ab8227, 1:2000, Abcam, Cambridge, MA), and Na+/K+ ATPase (Ab76020, 1:20,000, Abcam). The membranes were washed and species-specific HRP-conjugated secondary antibodies were added to the blots for 1 hour. Supersignal West Dura Extended Duration Substrate (Pierce Biotechnology) was used for chemiluminescent detection of proteins with a Fluorchem Imager (ProteinSimple, Santa Clara, CA). Semiquantitation of bands was performed using the AlphaView Software (ProteinSimple). β-Actin or Na+/K+ ATPase were used as loading controls where appropriate.

RNA Isolation and Real-Time Quantitative Polymerase Chain Reaction.

BeWo cells were collected in buffer RLT provided in the RNeasy Mini Kit (Qiagen, Germantown, MD), plus 1% β-mercaptoethanol. Cells were lysed using QIAshredder columns (Qiagen), and total RNA was isolated with the RNeasy Mini Kit (Qiagen) according to the manufacturer’s protocol. Total RNA concentration and purity (260/280) were determined using a Nanodrop spectrophotometer (Fisher Scientific). Complementary DNA (cDNA) was generated from total RNA (500 ng) using the High-Capacity cDNA Reverse Transcription Kit (Life Technologies) and a MultiGene OptiMax Thermal Cycler (Labnet International Inc., Edison, NJ). Quantitative PCR was performed with specific forward and reverse primers (Integrated DNA Technologies, Inc., Coralville, IA), cDNA, Sybr Green dye (Life Technologies), and a ViiA7 RT-PCR System (Life Technologies) in the Bionomics Research and Technology Center at Rutgers University. Ct values were converted to delta delta Ct values by comparison with ribosomal protein 13A (RPL13A) as a reference gene and the DMSO-treated control cells. Primer sequences for BCRP and RPL13A are provided in (Supplemental Table 1).

Patient Selection.

Written informed consent was obtained and placentas were collected from five healthy women with uncomplicated pregnancies after term delivery by scheduled cesarean section. Inclusion criteria were healthy women, aged 18–40, term gestation (≥36 weeks), and scheduled cesarean section without labor. Exclusion criteria included chronic medical conditions (e.g., hypertension, diabetes, autoimmune disorders); pregnancy-induced medical conditions (e.g., pregnancy-induced hypertension, pre-eclampsia, gestational diabetes); maternal infection; clinical chorioamnionitis; medication use (with the exception of prenatal vitamins); maternal smoking, alcohol, or drug abuse; and known fetal chromosomal abnormalities. All placentas expressed two wild-type alleles (C/C) at the 421 nucleotide position in the ABCG2 gene as determined by a Fluidigm Biomark Genetic Analysis system in the Bionomics Research and Technology Center at Rutgers University. Other patient demographic information is provided in (Supplemental Table 2). The Institutional Review Boards of Robert Wood Johnson Medical School (Protocol 0220100258) and Rutgers University (Protocol E12-024) approved this study. Whereas the range of maternal ages in this study was 34–39 years, no effect of maternal age on placental BCRP expression has been documented.

Placental Explants.

All placentas were obtained within 10 minutes of delivery and processed within 2 hours. Placentas were carefully inspected for any visible abnormalities and location of umbilical cord. Only placentas with central or eccentric cord insertion were used. The maternal decidua and the chorionic plate along the overlying membranes were removed, and sections of villous tissue were washed in PBS three times to remove maternal blood before dissection into 2 × 2 × 2-mm (8 mm3) pieces of tissue. In a 24-well dish, two pieces of 8-mm3 villous tissue were cultured in DMEM:F12 media without phenol red (Life Technologies) and with 10% charcoal-stripped and dextran-treated fetal bovine serum (Atlanta Biologicals) and 1% penicillin-streptomycin (Life Technologies). To allow for complete degeneration and regeneration of the syncytium as described by other laboratories (Siman et al., 2001), explants were maintained in culture for 5 days, with the media changed and collected every 24 hours. On day 5, genistein (0–10 μM) treatment began for 48 hours (media not changed during 48 hours of treatment). Genistein was dissolved in DMSO, and the final DMSO percentage was 0.1% (v/v) in the treatment media. Following the 48-hour treatment, explants were washed in PBS and frozen in liquid nitrogen before homogenization in sucrose (250 mM)-Tris (10 mM) buffer (pH 7.4) with protease inhibitors (1%, v/v), using the TissueLyser LT (Qiagen) according to the manufacturer’s protocol.

hCG ELISA and LDH Assay.

Each day of explant culture, media were collected for assessment of syncytiotrophoblast function and overall tissue integrity by quantification of human chorionic gonadotropin (hCG) and lactate dehydrogenase (LDH), respectively. The hCG ELISA was completed using the manufacturer’s protocol (Calbiotech, Spring Valley, CA). Activity of LDH in the media was determined using the manufacturer’s protocol.

Statistical Analysis.

Data are presented as mean ± S.D. of multiple independent experiments (n = 3–5) and analyzed using Graphpad Prism 5.0 (Graphpad Software Inc., La Jolla, CA). Two-way analysis of variance with Bonferroni post-test, One-way analysis of variance with Newman-Keuls post-test, or a two-tailed student’s t test were used to assess statistical significance (P < 0.05) according to the number of comparisons and variables. Nonlinear regression analysis (dose-response: [log] inhibitor versus response—variable slope (four parameters) or Michaelis-Menten) was used to determine kinetic parameters (IC50, Km, Jmax).

Results

Functional Inhibition of BCRP by Genistein

WT- and C421A-BCRP Overexpressing HEK Cells.

Whole-cell and cell-surface protein expression of BCRP were assessed by Western blot and flow cytometry, respectively. Three independent experiments revealed that BCRP protein expression in whole-cell lysates was reduced by about 30% in C421A-BCRP expressing cells compared with WT-BCRP expressing cells (P = 0.172) (Fig. 1A). At the cell surface, BCRP protein expression in the C421A-BCRP cells was significantly decreased by 50% compared with the WT cells (Fig. 1B). Both methods confirmed the absence of BCRP protein in HEK cells expressing the EV (data not shown).

Fig. 1.
  • Download figure
  • Open in new tab
  • Download powerpoint
Fig. 1.

Characterization of BCRP protein in WT- and C421A-BCRP–overexpressing HEK cells. (A) BCRP protein expression in HEK whole-cell lysates was determined by Western blot (10 µg protein homogenate/lane). Na+/K+ ATPase was used as a loading control. Western blot data are presented as a representative Western blot from one experiment. The bar graph shows the semiquantitation of band densities and represents the mean ± S.D. from three independent experiments. (B) BCRP protein expression on the cell surface of HEK cells was determined by flow cytometry. Cells were incubated for 45 minutes with the phycoerthyrin-labeled anti-BCRP antibody (5D3) or the phycoerthyrin-labeled negative control IgG antibody (green: WT-BCRP 5D3 stained cells, blue: C421A-BCRP 5D3 stained cells, red: WT-BCRP IgG control). Flow cytometry histogram data are presented as one representative experiment. Bar graph represents mean ± S.D. fluorescence intensity of individual cells from three independent experiments. †Statistically significant differences (P < 0.05) compared with WT-BCRP.

Two substrate accumulation assays (Hoechst 33342 and 3H-glyburide) were used to examine modulation of BCRP transport activity by pharmacologic inhibition and genetic variation. Initial experiments determined the optimal substrate concentrations for use in the two accumulation assays [Hoechst 33342, 7 µM and 10 µM unlabeled glyburide, and 0.1 µM 3H-glyburide; (Supplemental Fig. 1)]. In the absence of inhibitor, there was a trend for the cells overexpressing the variant BCRP (C421A) to accumulate 50%–100% more Hoechst 33342 or 3H-glyburide than the respective WT-BCRP cells (Fig. 2). The BCRP-specific inhibitor Ko143 increased the accumulation of Hoechst 33342 and 3H-glyburide in a concentration-dependent manner in both BCRP genotypes (Fig. 2, A and C), demonstrating the ability of the assays to detect inhibition of BCRP activity. Similar to Ko143, genistein increased the accumulation of Hoechst 33342 and 3H-glyburide in WT- and C421A-BCRP expressing cells (Fig. 2, B and D). Confirming the involvement of the BCRP transporter in the genistein-induced substrate accumulation, EV cells lacking BCRP protein accumulated both substrates, which was not altered by genistein (data not shown). It should be noted that Ko143 significantly increased the accumulation of both BCRP substrates in the C421A-BCRP cells at lower concentrations than in WT-BCRP cells. Further, the half-maximal inhibitory concentration (IC50) value for the inhibition of 3H-glyburide transport in the C421A-BCRP (10.1 ± 3.11 nM) cells by Ko143 was 50% lower than the WT-BCRP cells (21.5 ± 1.81 nM) (Table 1). For genistein, the IC50 values for the inhibition of 3H-glyburide transport in both BCRP genotypes were comparable (WT: 4.65 ± 0.27, C421A: 3.92 ± 1.26) (Table 1).

Fig. 2.
  • Download figure
  • Open in new tab
  • Download powerpoint
Fig. 2.

Inhibition of BCRP transport in WT- and C421A-BCRP overexpressing HEK cells. BCRP function was assessed by measuring the cellular accumulation of (A, B) Hoechst 33342 (7 µM) or (C, D) 3H-glyburide (10 µM unlabeled glyburide, 0.1 μM 3H-glyburide) in the presence of increasing concentrations of the BCRP-specific inhibitor, Ko143 or genistein. Intracellular fluorescence and radioactivity were quantified by a Cellometer Vision or a liquid scintillation counter, respectively. Bar graphs represent mean ± S.D. (n = 3 independent experiments). *Statistically significant differences (P < 0.05) compared with 0 µM genotype control. †Statistically significant differences (P < 0.05) compared with WT-BCRP control.

View this table:
  • View inline
  • View popup
TABLE 1

Inhibition of 3H-glyburide transport in BCRP-overexpressing cells and placental BeWo cells

To determine the mechanism by which genistein inhibited the BCRP-mediated transport of glyburide, accumulation experiments were performed using varying concentrations of both glyburide and genistein. Genistein significantly decreased the Km value for glyburide transport by 80% without changing the Jmax in either BCRP genotype (Fig. 3; Table 2), suggesting that genistein competitively inhibited the BCRP-mediated efflux of glyburide. In addition, the mean rate of 3H-glyburide accumulation in the genistein-treated cells (2 and 10 μM) was significantly greater than the mean rate of 3H-glyburide accumulation in the control cells in both genotypes (0 μM genistein) (Fig. 3).

Fig. 3.
  • Download figure
  • Open in new tab
  • Download powerpoint
Fig. 3.

Characterization of the genistein-glyburide interaction mediated by BCRP. BCRP function was assessed in WT- and C421A-BCRP HEK-expressing cells by measuring the cellular accumulation of 3H-glyburide (0–500 μM unlabeled glyburide, 0.1 μM 3H-glyburide) in the presence of increasing concentrations of genistein (0–10 µM) and was quantified using a liquid scintillation counter. Data represent mean ± S.D. (n = 3 independent experiments). Nonlinear regression analysis (Michaelis-Menten) was used for curve-fitting analysis. *Statistically significant differences (P < 0.05) in the mean rate of 3H-glyburide accumulation compared with the 0 µM control.

View this table:
  • View inline
  • View popup
TABLE 2

Kinetic parameters of glyburide transport in HEK cells overexpressing BCRP protein (WT or C421A)a

Placental BeWo Cells.

Expression of endogenous BCRP protein in placental BeWo cells was confirmed by Western blot along with BCRP protein expression in plasma membranes isolated from three individual placentas (Fig. 4A). BCRP function in BeWo cells was assessed using two substrate accumulation assays (Hoechst 33342 and 3H-glyburide) (Supplemental Fig. 2). Ko143 and genistein significantly increased the accumulation of both Hoechst 33342 and 3H-glyburide by 30%–100% in placental BeWo cells (Fig. 4, B–E). Notably, concentrations as low as 0.01 µM genistein inhibited 3H-glyburide transport (IC50 = 0.18 ± 0.22 μM; Table 1). Prototypical inhibitors of other efflux transporters (MDR1: PSC833: 2 µM; MRPs: 25 µM MK571) did not alter the accumulation of 3H-glyburide in the BeWo cells (data not shown), supporting the specific involvement of BCRP in the inhibition of glyburide transport by genistein.

Fig. 4.
  • Download figure
  • Open in new tab
  • Download powerpoint
Fig. 4.

Inhibition of BCRP transport in placental BeWo cells. (A) BCRP protein expression in placental BeWo whole-cell lysates compared with human placenta plasma membrane fractions was determined by Western blot (9 µg of protein homogenate/lane). β-Actin was used as a loading control. (B–E) BCRP function was assessed in the presence of increasing concentrations of Ko143 (B, D) or genistein (C, E), by the accumulation of (B and C) Hoechst 33342 (15 µM), or (D, E) 3H-glyburide (0.1 μM). Intracellular fluorescence or radioactivity was quantified using a Nexcelom Cellometer Vision or a liquid scintillation counter, respectively. Bar graphs represent mean ± S.D. (n = 3 or 4 independent experiments). *Statistically significant differences (P < 0.05) compared with the 0 µM control.

Regulation of Placental BCRP Expression by Genistein

BeWo Cells.

To determine whether genistein could alter the transcriptional regulation of BCRP expression, placental BeWo cells were incubated with genistein for 48 hours. Compared with control cells, genistein significantly decreased BCRP mRNA and protein expression up to 40% (Fig. 5, A and B). Furthermore, 48-hour exposure to genistein (5 μM) increased the accumulation of 3H-glyburide by 30% in placental BeWo cells, which was comparable to the pharmacologic inhibition of glyburide transport by Ko143 (100 nM) (Fig. 5C). Notably, genistein did not affect mRNA and protein expression of other efflux transporters, including the multidrug resistance-associated protein 1 (MRP1) (data not shown). Additionally, no difference was found in cell morphology or the syncytialization marker, syncytin mRNA expression, suggesting that genistein did not alter BeWo cell differentiation (data not shown). Because genistein is a phytoestrogen, the mechanism by which it downregulated BCRP mRNA and protein expression in BeWo cells was investigated using the estrogen receptor α antagonist ICI 182,780. Exposure to ICI 182,780 (1 µM) for 48 hours did not alter BCRP protein expression; however, the combination of genistein and ICI 182,780 together abolished the downregulation of BCRP protein expression caused by genistein alone (Fig. 6).

Fig. 5.
  • Download figure
  • Open in new tab
  • Download powerpoint
Fig. 5.

Regulation of BCRP transporter expression and function in placental BeWo cells. After a 48-hour exposure to genistein (0–10 µM), (A) qPCR was used to quantify BCRP and housekeeping gene, RPL13A, mRNA expression in placental BeWo cells. (B) BCRP protein expression in placental BeWo whole-cell lysates was determined by Western blot (10 µg of protein homogenate/lane). β-Actin was used as a loading control. Western blot data are presented as a representative Western blot from one experiment. (C) BCRP function was assessed by the cellular accumulation of 3H-glyburide (0.1 μM), which was quantified using a liquid scintillation counter. All bar graphs represent mean ± S.D. (n = 3 or 4 independent experiments). *Statistically significant differences (P < 0.05) compared with the 0 µM genistein control.

Fig. 6.
  • Download figure
  • Open in new tab
  • Download powerpoint
Fig. 6.

Estrogen receptor-mediated regulation of the BCRP transporter in placental BeWo cells. BCRP protein expression in placental BeWo whole-cell lysates was determined by Western blot (10 µg of protein homogenate/lane) after a 48-hour exposure to the estrogen receptor antagonist, ICI 182,780 in the presence and absence of genistein. β-Actin was used as a loading control. All Western blot data are presented as a representative Western blot from one experiment. The bar graphs are the semiquantitation of band density and represent the mean ± S.D. from three independent experiments. *Statistically significant differences (P < 0.05) compared with the 0 µM control.

Placental Explants.

Additional experiments aimed to determine whether genistein-mediated downregulation of BCRP expression could occur in native placental tissue. Explants were obtained from healthy human term placentas and allowed to undergo shedding and syncytialization for 5 days before treatment with genistein on days 5–7. Viability of the explants was confirmed by a decrease in LDH activity in the media over seven days (Supplemental Fig. 3A; Siman et al., 2001). The degree of syncytialization was verified by detection of hCG in the media and by histologic analysis (Supplemental Fig. 3B and 3C) (Siman et al., 2001)). Genistein treatment did not affect LDH activity or hCG secretion. Furthermore, BCRP protein expression was not altered by genistein (1–10 µM, 48 hours) in human term placental explants (Fig. 7).

Fig. 7.
  • Download figure
  • Open in new tab
  • Download powerpoint
Fig. 7.

Regulation of BCRP transporter expression in human term placental explants. Five healthy human term placentas were collected and processed within 2 hour of delivery. Explants were cultured for 5 days with the media replaced every day, before treatment with genistein (1-10 µM) on day 5 for 48 hour. BCRP protein expression in total explant lysates was determined by western blot (5 µg protein homogenate/lane). β-Actin was used as a loading control. Western blot data are presented as a representative western blot from one placenta. The scatter dot plot is the semiquantitation of band density and represents five individual placentas with mean ± S.D.

Discussion

The present study demonstrated the influence of genetic and dietary factors on the BCRP-mediated transport of glyburide using complementary in vitro and ex vivo placenta model systems. The C421A-BCRP genotype alone reduced the transport of 3H-glyburide compared with WT-BCRP control cells, whereas genistein competitively inhibited 3H-glyburide transport by BCRP to a similar extent in both genotypes. Confirming the potential for a placenta-specific glyburide accumulation, the BCRP-mediated transport of 3H-glyburide was inhibited by a short-term exposure (1 hour) to genistein in placental BeWo cells. Moreover, BCRP mRNA, protein, and function were reduced in BeWo cells exposed to genistein for 48 hours; however, the same genistein exposure did not alter BCRP protein expression in normal placental explant tissues. Results from the present study support future investigations that consider genetic and environmental (dietary genistein) factors when optimizing glyburide treatment in GD patients.

In this study, we confirmed the reduced capability of the C421A-BCRP protein to transport 3H-glyburide in HEK cells that overexpress the mutated BCRP protein (Q141K) compared with WT-BCRP overexpressing cells (Fig. 2; Table 2). Whereas Pollex et al. (2010) described BCRP protein cell-surface expression to be equal between genotypes, we observed less total (30%) and cell-surface (50%, P < 0.05) BCRP protein expression in the C421A-BCRP HEK cells (Fig. 1). Considering these findings, altered BCRP function in our experiments may be due to reduced BCRP protein trafficking to the cell surface, in line with other studies reporting decreased BCRP protein expression and function in C421A-BCRP–overexpressing cells (Imai et al., 2002; Kondo et al., 2004; Tamura et al., 2007, Furukawa et al., 2009; Woodward et al., 2013). In human tissue, the heterozygous variant genotype (421C/A) did not change BCRP protein expression in the intestine or placenta, but there was a significant decrease in BCRP protein expression in placentas of individuals homozygous for the SNP (421A/A) (Zamber et al., 2003; Kobayashi et al., 2005; Urquhart et al., 2008). Taken together, there may be differences in BCRP protein expression in cells or tissue based on the copy number of the C421A gene. Furthermore, there may be a cell-type and/or -tissue–specific effect of C421A on BCRP protein expression. Most importantly, patients expressing one or two variant alleles exhibit increased blood concentrations (sulfasalazine, diflomotecan, rosuvastatin) and enhanced side effects of drugs (gefitinib) that are substrates for BCRP (Sparreboom et al., 2004; Cusatis et al., 2006; Urquhart et al., 2008; Keskitalo et al., 2009). Because of these clinical findings and the frequent occurrence of the SNP, the International Transporter Consortium named the C421A BCRP genetic variant as a clinically relevant transporter polymorphism that should be evaluated in drug development studies (Giacomini et al., 2013).

Over the past 10 years, the sale and consumption of soy in the United States have dramatically increased, likely owing to the growing number of reports suggesting that a soy diet provides health benefits (Strom et al., 1999; Chen et al., 2003; Hussain et al., 2003; Constantinou et al., 2005; Bitto et al., 2008; Clarkson et al., 2011; Squadrito et al., 2013). Taken together with the increase in the prescribing of glyburide for GD (Camelo Castillo et al., 2014), there is a need to investigate the impact of soy on glyburide transport. Genistein and its conjugated metabolites (genistein-sulfate and genistein-glucuronide) are substrates for BCRP, suggesting that they competitively inhibit BCRP transport (Imai et al., 2004; Enokizono et al., 2007; Alvarez et al., 2011; Mease et al., 2012). Others, however, have proposed that genistein can noncompetitively inhibit BCRP transport via disruption of ATP hydrolysis as well (Randak et al., 1999; Di Pietro et al., 2002). To assess the mechanism of genistein inhibition, we used the 3H-glyburide accumulation assay (Pollex et al., 2010) and Michaelis-Menten nonlinear regression analysis to calculate kinetic parameters (Km and Jmax), which represent substrate affinity and rate of accumulation, respectively. It should be noted that because the assay measured 3H-glyburide accumulation, rather than rate of 3H-glyburide efflux, the kinetic parameters trended in the opposite direction of what is normally observed (i.e., decrease in Km indicates reduced affinity of 3H-glyburide for BCRP rather than increased affinity). In cells overexpressing both the WT-BCRP and the C421A-BCRP cells, genistein competitively inhibited the BCRP-mediated transport of 3H-glyburide to similar degrees (Figs. 2D and 3; Table 2). The Km and Jmax values derived from these experiments, however, were calculated for direct comparison with each other and cannot be directly extrapolated to an in vivo situation. Determining Km and Vmax in a study that measures 3H-glyburide efflux rather than accumulation may better correlate to an in vivo glyburide-genistein interaction. Although the various studies have demonstrated genistein to interfere with the transport of other BCRP substrates (i.e., mitoxantrone, enrofloxacin) (Zhang et al., 2004; Pulido et al., 2006), this is the first report implicating genistein in the inhibition of 3H-glyburide transport by BCRP. It is important to note that Ko143 significantly reduced 3H-glyburide transport in the C421A-BCRP overexpressing cells at a lower concentration than the WT-BCRP overexpressing cells, whereas genistein equally inhibited 3H-glyburide transport between cell types (Table 1). This finding suggests that individuals with the C421A-BCRP genotype may be at a greater risk for chemically induced BCRP inhibition depending on the inhibitor compound.

BeWo cells are commonly used as a model of placental transport because they endogenously express functional BCRP protein and produce the placenta-specific hormone, hCG (Takeuchi et al., 1990). In placental BeWo cells, genistein increased the accumulation of Hoechst 33342 and 3H-glyburide (Fig. 4). Interestingly, the concentrations of genistein that inhibited 3H-glyburide transport out of the BeWo cells were quite low and within the range of those observed in the plasma or serum of people consuming a soy diet (0.01–3 µM) (Arai et al., 2000; Uehar et al., 2000; Frankenfeld et al., 2003; Gardner et al., 2009). These data provide plausibility to the assertion that genistein may be able to inhibit BCRP transport of substrates in vivo. The BCRP-specific inhibitor, Ko143, was used as a positive control to confirm the involvement of BCRP in the genistein-mediated cellular accumulation of Hoechst 33342 and 3H-glyburide.

Placental BCRP function may also be affected by chemical-mediated changes in mRNA and/or protein expression. After 48-hour exposure to genistein, BCRP mRNA and protein expression was decreased in BeWo cells compared with the vehicle treated cells (Fig. 5, A and B). In turn, this caused significant accumulation of 3H-glyburide in cells that were exposed to genistein (5 μM, 48 hours) (Fig. 5C). Only one other study has reported a significant decrease in ABCG2 mRNA expression after an in vitro genistein exposure (15 µM, 24 hours, gastric cancer cells, MGC803) (Huang et al., 2014), whereas many others detected no change in BCRP mRNA and/or protein expression in other cell types (Imai et al., 2004; Ebert et al., 2007; Arias et al., 2014).

In the 1960s, genistein was recognized as a phytoestrogen because of its ability to alter reproductive function in sheep (Barrett et al., 1965) and agonize both ERα (IC50= 145 nM) and β (IC50= 8.4 nM) with a greater affinity for ERβ (Martin et al., 1978; Kuiper et al., 1998). This is unlike the endogenous ligand, 17β-estradiol, which agonizes both ERα (IC50= 0.93 nM) and ERβ (IC50= 1.06 nM) with similar affinities (Kuiper et al., 1998). Importantly, an estrogen response element has been identified in the promoter region of the ABCG2 gene (Ee et al., 2004b). Furthermore, 17β-estradiol has been shown to downregulate BCRP protein expression in various cells and tissues, including placental BeWo cells (Imai et al., 2005; Wang et al., 2006; Mahringer and Fricker, 2010), which express both ERα and ERβ (Gambino et al., 2012). It should be noted, however, that other studies have observed an upregulation of BCRP protein by 17β-estradiol in BeWo cells (Ee et al., 2004a; Prouillac et al., 2009) and cytotrophoblasts (Evseenko, et al., 2006). Nonetheless, we aimed to explore the involvement of the ER signaling pathway in the genistein-mediated downregulation of BCRP expression in placental BeWo cells, the ERα antagonist ICI 182,780 (1 μM) (Van Den Bemd et al., 1999; Peekhaus, et al., 2004) alone did not alter BCRP expression but was able to prevent the downregulation of BCRP by genistein (Fig. 6). These findings suggest that ER signaling participates in the repression of BCRP expression by genistein in BeWo cells.

Placental explants are an ex vivo model of the human term placenta as they retain the morphology of the human placental villi, contain multiple cell types, and are frequently used in examining transporter regulation in normal human placenta (Atkinson et al., 2006; Javam et al., 2014). Genistein did not alter BCRP protein expression in human term placental explants (Fig. 7). Although these findings contrast with those observed in placental BeWo cells, it is important to note that extrapolation of gene regulation findings observed in choriocarcinoma cells to normal placenta must be made with caution. DNA methylation patterns vary between normal primary trophoblasts and choriocarcinoma cells, contributing to the overall differential gene expression and regulation profiles between the two types of cells (Novakovic et al., 2011). Additionally, whereas explants are a model of the term placenta, it is important to note that BeWo cells are generally representative of first trimester trophoblasts (Wice et al., 1990), and therefore differences in the regulation of protein expression between the two models is conceivable. Furthermore, explants offer a more complex system than trophoblasts alone. Capillary endothelial cells also express BCRP (Maliepaard et al., 2001) and may confound the results from the explant studies as the Western blot results represent BCRP expression in the whole explant homogenate and not trophoblasts alone. Future research should address the regulation of BCRP expression in explants using immunohistochemistry to localize BCRP expression or by using isolated primary trophoblasts. Together, results from this study indicate that the direct pharmacologic inhibition of BCRP by genistein may have greater implications for BCRP-mediated transport of glyburide than modulation of transcription and/or translation.

The prescription of glyburide for the management of GD has reached an all-time high as most initial reports found no differences in neonatal hypoglycemia rates between insulin- and glyburide-managed GD (Langer et al., 2000; Jacobson et al., 2005; Anjalakshi et al., 2007). More recently, Schartz and colleagues described a weak, but significant, negative correlation between neonatal blood glucose concentration and umbilical cord blood glyburide concentration (Schwartz et al., 2015). Interindividual differences have been found in the umbilical cord blood to maternal blood concentration ratios of glyburide for which the authors named genetic differences in the BCRP/ABCG2 gene as a likely contributor. Differences in diets, including those that are rich in soy, may also contribute to this variability.

In summary, our data demonstrate that genistein inhibits the BCRP-mediated efflux of glyburide in vitro by direct inhibition and reduced protein expression in placental BeWo cells but not placental explants. To better optimize the individualized prescribing of glyburide for GD, future research should address the contribution of the C421A-BCRP genotype and genistein in the diet to the transplacental passage of glyburide.

Acknowledgments

The authors thank Dr. Robert Robey, National Institutes of Health National Cancer Institute, for the empty vector, wild-type, and C421A-BCRP overexpressing HEK cells.

Authorship Contributions

Participated in research design: Bircsak, Aleksunes.

Conducted experiments: Bircsak, Gupta, Gorczyca.

Provided facilities and expertise in placenta collection: Yuen, Vetrano, Weinberger.

Wrote or contributed to the writing of the manuscript: Bircsak, Aleksunes, Gupta, Yuen, Vetrano, Weinberger.

Footnotes

    • Received October 30, 2015.
    • Accepted February 2, 2016.
  • This work was supported by the National Institutes of Health National Institutes of Environmental Health Sciences [Grants ES020522, ES005022, ES007148, ES020721]. Kristin Bircsak was supported by predoctoral fellowships from the American Foundation for Pharmaceutical Education and Pharmaceutical Research and Manufacturers of America.

  • dx.doi.org/10.1124/jpet.115.230185.

  • ↵Embedded ImageThis article has supplemental material available at jpet.aspetjournals.org.

Abbreviations

ABC
ATP-binding cassette
BCA
bicinchoninic acid
BCRP
breast cancer resistance protein
BSA
bovine serum albumin
cDNA
complementary DNA
DMSO
dimethyl sulfoxide
ER
estrogen receptor
EV
empty vector
GD
gestational diabetes
hCG
human chorionic gonadotropin
HEK
human embryonic kidney 293
IC50
half maximal inhibitory concentration
INN
international nonproprietary name
Jmax
maximum accumulation rate
Km
substrate concentration of half the maximum accumulation rate
LDH
lactate dehydrogenase
MDR1
multidrug resistance protein 1
MRP
multidrug resistance-associated protein
PCR
polymerase chain reaction
RPL13A
ribosomal protein L13A
WT
wild-type
  • Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics

References

  1. ↵
    1. Álvarez AI,
    2. Vallejo F,
    3. Barrera B,
    4. Merino G,
    5. Prieto JG,
    6. Tomás-Barberán F, and
    7. Espín JC
    (2011) Bioavailability of the glucuronide and sulfate conjugates of genistein and daidzein in breast cancer resistance protein 1 knockout mice. Drug Metab Dispos 39:2008–2012.
    OpenUrlAbstract/FREE Full Text
  2. ↵
    1. Anjalakshi C,
    2. Balaji V,
    3. Balaji MS, and
    4. Seshiah V
    (2007) A prospective study comparing insulin and glibenclamide in gestational diabetes mellitus in Asian Indian women. Diabetes Res Clin Pract 76:474–475.
    OpenUrlCrossRefPubMed
  3. ↵
    1. Arai Y,
    2. Uehara M,
    3. Sato Y,
    4. Kimira M,
    5. Eboshida A,
    6. Adlercreutz H, and
    7. Watanabe S
    (2000) Comparison of isoflavones among dietary intake, plasma concentration and urinary excretion for accurate estimation of phytoestrogen intake. J Epidemiol 10:127–135.
    OpenUrlCrossRefPubMed
  4. ↵
    1. Arias A,
    2. Rigalli JP,
    3. Villanueva SS,
    4. Ruiz ML,
    5. Luquita MG,
    6. Perdomo VG,
    7. Vore M,
    8. Catania VA, and
    9. Mottino AD
    (2014) Regulation of expression and activity of multidrug resistance proteins MRP2 and MDR1 by estrogenic compounds in Caco-2 cells: role in prevention of xenobiotic-induced cytotoxicity. Toxicology 320:46–55.
    OpenUrlCrossRef
  5. ↵
    1. Atkinson DE,
    2. Sibley CP,
    3. Fairbairn LJ, and
    4. Greenwood SL
    (2006) MDR1 P-gp expression and activity in intact human placental tissue; upregulation by retroviral transduction. Placenta 27:707–714.
    OpenUrlCrossRefPubMed
  6. ↵
    1. Barrett J,
    2. George J, and
    3. Lamond D
    (1965) Reproductive performance of Merino ewes grazing red clover (Trifolium pratense L.), improved pasture, or native pasture. Aust J Agric Res 16:189–200.
    OpenUrlCrossRef
  7. ↵
    1. Bertini AM,
    2. Silva JC,
    3. Taborda W,
    4. Becker F,
    5. Lemos Bebber FR,
    6. Zucco Viesi JM,
    7. Aquim G, and
    8. Engel Ribeiro T
    (2005) Perinatal outcomes and the use of oral hypoglycemic agents. J Perinat Med 33:519–523.
    OpenUrlCrossRefPubMed
  8. ↵
    1. Bircsak KM,
    2. Gibson CJ,
    3. Robey RW, and
    4. Aleksunes LM
    (2013) Assessment of drug transporter function using fluorescent cell imaging. Curr Protoc Toxicol 57:23.1.1-23.6.15.
  9. ↵
    1. Bitto A,
    2. Burnett BP,
    3. Polito F,
    4. Marini H,
    5. Levy RM,
    6. Armbruster MA,
    7. Minutoli L,
    8. Di Stefano V,
    9. Irrera N,
    10. Antoci S,
    11. et al.
    (2008) Effects of genistein aglycone in osteoporotic, ovariectomized rats: a comparison with alendronate, raloxifene and oestradiol. Br J Pharmacol 155:896–905.
    OpenUrlCrossRefPubMed
  10. ↵
    1. Camelo Castillo W,
    2. Boggess K,
    3. Stürmer T,
    4. Brookhart MA,
    5. Benjamin DK Jr., and
    6. Jonsson Funk M
    (2014) Trends in glyburide compared with insulin use for gestational diabetes treatment in the United States, 2000-2011. Obstet Gynecol 123:1177–1184.
    OpenUrlCrossRefPubMed
  11. ↵
    1. Chen YM,
    2. Ho SC,
    3. Lam SS,
    4. Ho SS, and
    5. Woo JL
    (2003) Soy isoflavones have a favorable effect on bone loss in Chinese postmenopausal women with lower bone mass: a double-blind, randomized, controlled trial. J Clin Endocrinol Metab 88:4740–4747.
    OpenUrlCrossRefPubMed
  12. ↵
    Clarkson TBH UW, Allmen TI, Aso T, Barnes S, Basaria SS, Brinton RD, Frankenfeld CL, Gallagher JC, Gold EB, Hodis HN, et al. (2011) The role of soy isoflavones in menopausal health: report of The North American Menopause Society/Wulf H. Utian Translational Science Symposium in Chicago, IL (October 2010). Menopause 18:732–753.
  13. ↵
    1. Constantinou AI,
    2. White BE,
    3. Tonetti D,
    4. Yang Y,
    5. Liang W,
    6. Li W, and
    7. van Breemen RB
    (2005) The soy isoflavone daidzein improves the capacity of tamoxifen to prevent mammary tumours. Eur J Cancer 41:647–654.
    OpenUrlCrossRefPubMed
  14. ↵
    1. Cusatis G,
    2. Gregorc V,
    3. Li J,
    4. Spreafico A,
    5. Ingersoll RG,
    6. Verweij J,
    7. Ludovini V,
    8. Villa E,
    9. Hidalgo M,
    10. Sparreboom A,
    11. et al.
    (2006) Pharmacogenetics of ABCG2 and adverse reactions to gefitinib. J Natl Cancer Inst 98:1739–1742.
    OpenUrlAbstract/FREE Full Text
  15. ↵
    1. Dabelea D,
    2. Snell-Bergeon JK,
    3. Hartsfield CL,
    4. Bischoff KJ,
    5. Hamman RF,
    6. McDuffie RS, and
    7. Kaiser Permanente of Colorado GDM Screening Program
    (2005) Increasing prevalence of gestational diabetes mellitus (GDM) over time and by birth cohort: Kaiser Permanente of Colorado GDM Screening Program. Diabetes Care 28:579–584.
    OpenUrlAbstract/FREE Full Text
  16. ↵
    1. DeSisto CL,
    2. Kim SY, and
    3. Sharma AJ
    (2014) Prevalence estimates of gestational diabetes mellitus in the United States, Pregnancy Risk Assessment Monitoring System (PRAMS), 2007–2010. Prev Chronic Dis 11:E104.
    OpenUrlPubMed
  17. ↵
    1. Di Pietro A,
    2. Conseil G,
    3. Pérez-Victoria JM,
    4. Dayan G,
    5. Baubichon-Cortay H,
    6. Trompier D,
    7. Steinfels E,
    8. Jault JM,
    9. de Wet H,
    10. Maitrejean M,
    11. et al.
    (2002) Modulation by flavonoids of cell multidrug resistance mediated by P-glycoprotein and related ABC transporters. Cell Mol Life Sci 59:307–322.
    OpenUrlCrossRefPubMed
  18. ↵
    1. Ebert B,
    2. Seidel A, and
    3. Lampen A
    (2007) Phytochemicals induce breast cancer resistance protein in Caco-2 cells and enhance the transport of benzo[a]pyrene-3-sulfate. Toxicol Sci 96:227–236.
    OpenUrlAbstract/FREE Full Text
  19. ↵
    1. Ee PL,
    2. He X,
    3. Ross DD, and
    4. Beck WT
    (2004a) Modulation of breast cancer resistance protein (BCRP/ABCG2) gene expression using RNA interference. Mol Cancer Ther 3:1577–1583.
    OpenUrlAbstract/FREE Full Text
  20. ↵
    1. Ee PLR,
    2. Kamalakaran S,
    3. Tonetti D,
    4. He X,
    5. Ross DD, and
    6. Beck WT
    (2004b) Identification of a novel estrogen response element in the breast cancer resistance protein (ABCG2) gene. Cancer Res 64:1247–1251.
    OpenUrlAbstract/FREE Full Text
  21. ↵
    1. Enokizono J,
    2. Kusuhara H, and
    3. Sugiyama Y
    (2007) Effect of breast cancer resistance protein (Bcrp/Abcg2) on the disposition of phytoestrogens. Mol Pharmacol 72:967–975.
    OpenUrlAbstract/FREE Full Text
  22. ↵
    1. Evseenko DA,
    2. Paxton JW, and
    3. Keelan JA
    (2006) ABC drug transporter expression and functional activity in trophoblast-like cell lines and differentiating primary trophoblast. Am J Physiol Regul Integr Comp Physiol 290:R1357–R1365.
    OpenUrlAbstract/FREE Full Text
  23. ↵
    1. Feinshtein V,
    2. Erez O,
    3. Ben-Zvi Z,
    4. Eshkoli T,
    5. Sheizaf B,
    6. Sheiner E, and
    7. Holcberg G
    (2013) Cannabidiol enhances xenobiotic permeability through the human placental barrier by direct inhibition of breast cancer resistance protein: an ex vivo study. Am J Obstet Gynecol 209:573.e1–573.e15.
    OpenUrlCrossRef
  24. ↵
    1. Ferrara A
    (2007) Increasing prevalence of gestational diabetes mellitus: a public health perspective. Diabetes Care 30 (Suppl 2):S141–S146.
    OpenUrlFREE Full Text
  25. ↵
    1. Frankenfeld CL,
    2. Patterson RE,
    3. Horner NK,
    4. Neuhouser ML,
    5. Skor HE,
    6. Kalhorn TF,
    7. Howald WN, and
    8. Lampe JW
    (2003) Validation of a soy food-frequency questionnaire and evaluation of correlates of plasma isoflavone concentrations in postmenopausal women. Am J Clin Nutr 77:674–680.
    OpenUrlAbstract/FREE Full Text
  26. ↵
    1. Furukawa T,
    2. Wakabayashi K,
    3. Tamura A,
    4. Nakagawa H,
    5. Morishima Y,
    6. Osawa Y, and
    7. Ishikawa T
    (2009) Major SNP (Q141K) variant of human ABC transporter ABCG2 undergoes lysosomal and proteasomal degradations. Pharm Res 26:469–479.
    OpenUrlCrossRefPubMed
  27. ↵
    1. Gambino YP,
    2. Pérez Pérez A,
    3. Dueñas JL,
    4. Calvo JC,
    5. Sánchez-Margalet V, and
    6. Varone CL
    (2012) Regulation of leptin expression by 17beta-estradiol in human placental cells involves membrane associated estrogen receptor alpha. Biochim Biophys Acta 1823:900–910.
    OpenUrlCrossRefPubMed
  28. ↵
    1. Gardner CD,
    2. Chatterjee LM, and
    3. Franke AA
    (2009) Effects of isoflavone supplements vs. soy foods on blood concentrations of genistein and daidzein in adults. J Nutr Biochem 20:227–234.
    OpenUrlCrossRefPubMed
  29. ↵
    1. Gedeon C,
    2. Anger G,
    3. Lubetsky A,
    4. Miller MP, and
    5. Koren G
    (2008a) Investigating the potential role of multi-drug resistance protein (MRP) transporters in fetal to maternal glyburide efflux in the human placenta. J Obstet Gynaecol 28:485–489.
    OpenUrlCrossRefPubMed
  30. ↵
    1. Gedeon C,
    2. Anger G,
    3. Piquette-Miller M, and
    4. Koren G
    (2008b) Breast cancer resistance protein: mediating the trans-placental transfer of glyburide across the human placenta. Placenta 29:39–43.
    OpenUrlCrossRefPubMed
  31. ↵
    1. Gedeon C,
    2. Behravan J,
    3. Koren G, and
    4. Piquette-Miller M
    (2006) Transport of glyburide by placental ABC transporters: implications in fetal drug exposure. Placenta 27:1096–1102.
    OpenUrlCrossRefPubMed
  32. ↵
    1. Giacomini KM,
    2. Balimane PV,
    3. Cho SK,
    4. Eadon M,
    5. Edeki T,
    6. Hillgren KM,
    7. Huang SM,
    8. Sugiyama Y,
    9. Weitz D,
    10. Wen Y,
    11. et al., and
    12. International Transporter Consortium
    (2013) International Transporter Consortium commentary on clinically important transporter polymorphisms. Clin Pharmacol Ther 94:23–26.
    OpenUrlCrossRefPubMed
  33. ↵
    Hemauer SJ, Patrikeeva SL, Nanovskaya TN, Hankins GD and Ahmed MS (2010) Role of human placental apical membrane transporters in the efflux of glyburide, rosiglitazone, and metformin. Am J Obstet Gynecol 202:383 e381–387.
  34. ↵
    1. Huang W,
    2. Wan C,
    3. Luo Q,
    4. Huang Z, and
    5. Luo Q
    (2014) Genistein-inhibited cancer stem cell-like properties and reduced chemoresistance of gastric cancer. Int J Mol Sci 15:3432–3443.
    OpenUrlCrossRefPubMed
  35. ↵
    1. Hussain M,
    2. Banerjee M,
    3. Sarkar FH,
    4. Djuric Z,
    5. Pollak MN,
    6. Doerge D,
    7. Fontana J,
    8. Chinni S,
    9. Davis J,
    10. Forman J,
    11. et al.
    (2003) Soy isoflavones in the treatment of prostate cancer. Nutr Cancer 47:111–117.
    OpenUrlCrossRefPubMed
  36. ↵
    1. Imai Y,
    2. Ishikawa E,
    3. Asada S, and
    4. Sugimoto Y
    (2005) Estrogen-mediated post transcriptional down-regulation of breast cancer resistance protein/ABCG2. Cancer Res 65:596–604.
    OpenUrlAbstract/FREE Full Text
  37. ↵
    1. Imai Y,
    2. Nakane M,
    3. Kage K,
    4. Tsukahara S,
    5. Ishikawa E,
    6. Tsuruo T,
    7. Miki Y, and
    8. Sugimoto Y
    (2002) C421A polymorphism in the human breast cancer resistance protein gene is associated with low expression of Q141K protein and low-level drug resistance. Mol Cancer Ther 1:611–616.
    OpenUrlAbstract/FREE Full Text
  38. ↵
    1. Imai Y,
    2. Tsukahara S,
    3. Asada S, and
    4. Sugimoto Y
    (2004) Phytoestrogens/flavonoids reverse breast cancer resistance protein/ABCG2-mediated multidrug resistance. Cancer Res 64:4346–4352.
    OpenUrlAbstract/FREE Full Text
  39. ↵
    1. Jacobson GF,
    2. Ramos GA,
    3. Ching JY,
    4. Kirby RS,
    5. Ferrara A, and
    6. Field DR
    (2005) Comparison of glyburide and insulin for the management of gestational diabetes in a large managed care organization. Am J Obstet Gynecol 193:118–124.
    OpenUrlCrossRefPubMed
  40. ↵
    1. Javam M,
    2. Audette MC,
    3. Iqbal M,
    4. Bloise E,
    5. Gibb W, and
    6. Matthews SG
    (2014) Effect of oxygen on multidrug resistance in term human placenta. Placenta 35:324–330.
    OpenUrlCrossRefPubMed
  41. ↵
    1. Keskitalo JE,
    2. Zolk O,
    3. Fromm MF,
    4. Kurkinen KJ,
    5. Neuvonen PJ, and
    6. Niemi M
    (2009) ABCG2 polymorphism markedly affects the pharmacokinetics of atorvastatin and rosuvastatin. Clin Pharmacol Ther 86:197–203.
    OpenUrlCrossRefPubMed
  42. ↵
    1. Kobayashi D,
    2. Ieiri I,
    3. Hirota T,
    4. Takane H,
    5. Maegawa S,
    6. Kigawa J,
    7. Suzuki H,
    8. Nanba E,
    9. Oshimura M,
    10. Terakawa N,
    11. et al.
    (2005) Functional assessment of ABCG2 (BCRP) gene polymorphisms to protein expression in human placenta. Drug Metab Dispos 33:94–101.
    OpenUrlAbstract/FREE Full Text
  43. ↵
    1. Kondo C,
    2. Suzuki H,
    3. Itoda M,
    4. Ozawa S,
    5. Sawada J,
    6. Kobayashi D,
    7. Ieiri I,
    8. Mine K,
    9. Ohtsubo K, and
    10. Sugiyama Y
    (2004) Functional analysis of SNPs variants of BCRP/ABCG2. Pharm Res 21:1895–1903.
    OpenUrlCrossRefPubMed
  44. ↵
    1. Kraemer J,
    2. Klein J,
    3. Lubetsky A, and
    4. Koren G
    (2006) Perfusion studies of glyburide transfer across the human placenta: implications for fetal safety. Am J Obstet Gynecol 195:270–274.
    OpenUrlCrossRefPubMed
  45. ↵
    1. Kuiper GG,
    2. Lemmen JG,
    3. Carlsson B,
    4. Corton JC,
    5. Safe SH,
    6. van der Saag PT,
    7. van der Burg B, and
    8. Gustafsson JA
    (1998) Interaction of estrogenic chemicals and phytoestrogens with estrogen receptor beta. Endocrinology 139:4252–4263.
    OpenUrlCrossRefPubMed
  46. ↵
    1. Langer O,
    2. Conway DL,
    3. Berkus MD,
    4. Xenakis EM-J, and
    5. Gonzales O
    (2000) A comparison of glyburide and insulin in women with gestational diabetes mellitus. N Engl J Med 343:1134–1138.
    OpenUrlCrossRefPubMed
  47. ↵
    1. Mahringer A and
    2. Fricker G
    (2010) BCRP at the blood-brain barrier: genomic regulation by 17β-estradiol. Mol Pharm 7:1835–1847.
    OpenUrlCrossRef
  48. ↵
    1. Maliepaard M,
    2. Scheffer GL,
    3. Faneyte IF,
    4. van Gastelen MA,
    5. Pijnenborg ACLM,
    6. Schinkel AH,
    7. van De Vijver MJ,
    8. Scheper RJ, and
    9. Schellens JHM
    (2001) Subcellular localization and distribution of the breast cancer resistance protein transporter in normal human tissues. Cancer Res 61:3458–3464.
    OpenUrlAbstract/FREE Full Text
  49. ↵
    1. Martin PM,
    2. Horwitz KB,
    3. Ryan DS, and
    4. McGuire WL
    (1978) Phytoestrogen interaction with estrogen receptors in human breast cancer cells. Endocrinology 103:1860–1867.
    OpenUrlCrossRefPubMed
  50. ↵
    1. Mease K,
    2. Sane R,
    3. Podila L, and
    4. Taub ME
    (2012) Differential selectivity of efflux transporter inhibitors in Caco-2 and MDCK-MDR1 monolayers: a strategy to assess the interaction of a new chemical entity with P-gp, BCRP, and MRP2. J Pharm Sci 101:1888–1897.
    OpenUrlCrossRefPubMed
  51. ↵
    1. Memon N,
    2. Bircsak KM,
    3. Archer F,
    4. Gibson CJ,
    5. Ohman-Strickland P,
    6. Weinberger BI,
    7. Parast MM,
    8. Vetrano AM, and
    9. Aleksunes LM
    (2014) Regional expression of the BCRP/ABCG2 transporter in term human placentas. Reprod Toxicol 43:72–77.
    OpenUrlCrossRef
  52. ↵
    1. Merino G,
    2. Perez M,
    3. Real R,
    4. Egido E,
    5. Prieto JG, and
    6. Alvarez AI
    (2010) In vivo inhibition of BCRP/ABCG2 mediated transport of nitrofurantoin by the isoflavones genistein and daidzein: a comparative study in Bcrp1 (-/-) mice. Pharm Res 27:2098–2105.
    OpenUrlCrossRefPubMed
  53. ↵
    1. Morisaki K,
    2. Robey RW,
    3. Ozvegy-Laczka C,
    4. Honjo Y,
    5. Polgar O,
    6. Steadman K,
    7. Sarkadi B, and
    8. Bates SE
    (2005) Single nucleotide polymorphisms modify the transporter activity of ABCG2. Cancer Chemother Pharmacol 56:161–172.
    OpenUrlCrossRefPubMed
  54. ↵
    1. Novakovic B,
    2. Gordon L,
    3. Wong NC,
    4. Moffett A,
    5. Manuelpillai U,
    6. Craig JM,
    7. Sharkey A, and
    8. Saffery R
    (2011) Wide-ranging DNA methylation differences of primary trophoblast cell populations and derived cell lines: implications and opportunities for understanding trophoblast function. Mol Hum Reprod 17:344–353.
    OpenUrlAbstract/FREE Full Text
  55. ↵
    1. Ogunyemi D,
    2. Jesse M, and
    3. Davidson M
    (2007) Comparison of glyburide versus insulin in management of gestational diabetes mellitus. Endocr Pract 13:427–428.
    OpenUrlCrossRefPubMed
  56. ↵
    1. Peekhaus NT,
    2. Chang T,
    3. Hayes EC,
    4. Wilkinson HA,
    5. Mitra SW,
    6. Schaeffer JM, and
    7. Rohrer SP
    (2004) Distinct effects of the antiestrogen Faslodex on the stability of estrogen receptors-alpha and -beta in the breast cancer cell line MCF-7. J Mol Endocrinol 32:987–995.
    OpenUrlAbstract
  57. ↵
    1. Pollex E,
    2. Lubetsky A, and
    3. Koren G
    (2008) The role of placental breast cancer resistance protein in the efflux of glyburide across the human placenta. Placenta 29:743–747.
    OpenUrlCrossRefPubMed
  58. ↵
    1. Pollex EK,
    2. Anger G,
    3. Hutson J,
    4. Koren G, and
    5. Piquette-Miller M
    (2010) Breast cancer resistance protein (BCRP)-mediated glyburide transport: effect of the C421A/Q141K BCRP single-nucleotide polymorphism. Drug Metab Dispos 38:740–744.
    OpenUrlAbstract/FREE Full Text
  59. ↵
    1. Prouillac C,
    2. Videmann B,
    3. Mazallon M, and
    4. Lecoeur S
    (2009) Induction of cells differentiation and ABC transporters expression by a myco-estrogen, zearalenone, in human choriocarcinoma cell line (BeWo). Toxicology 263:100–107.
    OpenUrlCrossRefPubMed
  60. ↵
    1. Pulido MM,
    2. Molina AJ,
    3. Merino G,
    4. Mendoza G,
    5. Prieto JG, and
    6. Alvarez AI
    (2006) Interaction of enrofloxacin with breast cancer resistance protein (BCRP/ABCG2): influence of flavonoids and role in milk secretion in sheep. J Vet Pharmacol Ther 29:279–287.
    OpenUrlCrossRefPubMed
  61. ↵
    1. Randak C,
    2. Auerswald EA,
    3. Assfalg-Machleidt I,
    4. Reenstra WW, and
    5. Machleidt W
    (1999) Inhibition of ATPase, GTPase and adenylate kinase activities of the second nucleotide-binding fold of the cystic fibrosis transmembrane conductance regulator by genistein. Biochem J 340:227–235.
    OpenUrlAbstract/FREE Full Text
  62. ↵
    1. Schwartz RA,
    2. Rosenn B,
    3. Aleksa K, and
    4. Koren G
    (2015) Glyburide transport across the human placenta. Obstet Gynecol 125:583–588.
    OpenUrlCrossRef
  63. ↵
    1. Simán CM,
    2. Sibley CP,
    3. Jones CJ,
    4. Turner MA, and
    5. Greenwood SL
    (2001) The functional regeneration of syncytiotrophoblast in cultured explants of term placenta. Am J Physiol Regul Integr Comp Physiol 280:R1116–R1122.
    OpenUrlAbstract/FREE Full Text
  64. ↵
    1. Sparreboom A,
    2. Gelderblom H,
    3. Marsh S,
    4. Ahluwalia R,
    5. Obach R,
    6. Principe P,
    7. Twelves C,
    8. Verweij J, and
    9. McLeod HL
    (2004) Diflomotecan pharmacokinetics in relation to ABCG2 421C>A genotype. Clin Pharmacol Ther 76:38–44.
    OpenUrlCrossRefPubMed
  65. ↵
    1. Squadrito F,
    2. Marini H,
    3. Bitto A,
    4. Altavilla D,
    5. Polito F,
    6. Adamo EB,
    7. D’Anna R,
    8. Arcoraci V,
    9. Burnett BP,
    10. Minutoli L,
    11. et al.
    (2013) Genistein in the metabolic syndrome: results of a randomized clinical trial. J Clin Endocrinol Metab 98:3366–3374.
    OpenUrlCrossRefPubMed
  66. ↵
    1. Strom SS,
    2. Yamamura Y,
    3. Duphorne CM,
    4. Spitz MR,
    5. Babaian RJ,
    6. Pillow PC, and
    7. Hursting SD
    (1999) Phytoestrogen intake and prostate cancer: a case-control study using a new database. Nutr Cancer 33:20–25.
    OpenUrlCrossRefPubMed
  67. ↵
    1. Takeuchi Y,
    2. Sakakibara R, and
    3. Ishiguro M
    (1990) Synthesis and secretion of human chorionic gonadotropin and its subunits in choriocarcinoma cells: a comparative study with normal placental cells. Mol Cell Endocrinol 69:145–156.
    OpenUrlCrossRefPubMed
  68. ↵
    1. Tamura A,
    2. Wakabayashi K,
    3. Onishi Y,
    4. Takeda M,
    5. Ikegami Y,
    6. Sawada S,
    7. Tsuji M,
    8. Matsuda Y, and
    9. Ishikawa T
    (2007) Re-evaluation and functional classification of non-synonymous single nucleotide polymorphisms of the human ATP-binding cassette transporter ABCG2. Cancer Sci 98:231–239.
    OpenUrlCrossRefPubMed
  69. ↵
    1. Traxler P,
    2. Green J,
    3. Mett H,
    4. Séquin U, and
    5. Furet P
    (1999) Use of a pharmacophore model for the design of EGFR tyrosine kinase inhibitors: isoflavones and 3-phenyl-4(1H)-quinolones. J Med Chem 42:1018–1026.
    OpenUrlCrossRefPubMed
  70. ↵
    1. Uehar M,
    2. Arai Y,
    3. Watanabe S, and
    4. Adlercreutz H
    (2000) Comparison of plasma and urinary phytoestrogens in Japanese and Finnish women by time-resolved fluoroimmunoassay. Biofactors 12:217–225.
    OpenUrlCrossRefPubMed
  71. ↵
    1. Urquhart BL,
    2. Ware JA,
    3. Tirona RG,
    4. Ho RH,
    5. Leake BF,
    6. Schwarz UI,
    7. Zaher H,
    8. Palandra J,
    9. Gregor JC,
    10. Dresser GK,
    11. et al.
    (2008) Breast cancer resistance protein (ABCG2) and drug disposition: intestinal expression, polymorphisms and sulfasalazine as an in vivo probe. Pharmacogenet Genomics 18:439–448.
    OpenUrlCrossRefPubMed
  72. ↵
    1. Van Den Bemd GJ,
    2. Kuiper GG,
    3. Pols HA, and
    4. Van Leeuwen JP
    (1999) Distinct effects on the conformation of estrogen receptor alpha and beta by both the antiestrogens ICI 164,384 and ICI 182,780 leading to opposite effects on receptor stability. Biochem Biophys Res Commun 261:1–5.
    OpenUrlCrossRefPubMed
  73. ↵
    1. Wang H,
    2. Zhou L,
    3. Gupta A,
    4. Vethanayagam RR,
    5. Zhang Y,
    6. Unadkat JD, and
    7. Mao Q
    (2006) Regulation of BCRP/ABCG2 expression by progesterone and 17β-estradiol in human placental BeWo cells. Am J Physiol Endocrinol Metab 290:E798–E807.
    OpenUrlAbstract/FREE Full Text
  74. ↵
    1. Wice B,
    2. Menton D,
    3. Geuze H, and
    4. Schwartz AL
    (1990) Modulators of cyclic AMP metabolism induce syncytiotrophoblast formation in vitro. Exp Cell Res 186:306–316.
    OpenUrlCrossRefPubMed
  75. ↵
    1. Williams AF
    (1997) Hypoglycaemia of the newborn: a review. Bull World Health Organ 75:261–290.
    OpenUrlPubMed
  76. ↵
    1. Woodward OM,
    2. Tukaye DN,
    3. Cui J,
    4. Greenwell P,
    5. Constantoulakis LM,
    6. Parker BS,
    7. Rao A,
    8. Köttgen M,
    9. Maloney PC, and
    10. Guggino WB
    (2013) Gout-causing Q141K mutation in ABCG2 leads to instability of the nucleotide-binding domain and can be corrected with small molecules. Proc Natl Acad Sci USA 110:5223–5228.
    OpenUrlAbstract/FREE Full Text
  77. ↵
    1. Zamber CP,
    2. Lamba JK,
    3. Yasuda K,
    4. Farnum J,
    5. Thummel K,
    6. Schuetz JD, and
    7. Schuetz EG
    (2003) Natural allelic variants of breast cancer resistance protein (BCRP) and their relationship to BCRP expression in human intestine. Pharmacogenetics 13:19–28.
    OpenUrlCrossRefPubMed
  78. ↵
    1. Zhang S,
    2. Yang X, and
    3. Morris ME
    (2004) Flavonoids are inhibitors of breast cancer resistance protein (ABCG2)-mediated transport. Mol Pharmacol 65:1208–1216.
    OpenUrlAbstract/FREE Full Text
  79. ↵
    1. Zhou L,
    2. Naraharisetti SB,
    3. Wang H,
    4. Unadkat JD,
    5. Hebert MF, and
    6. Mao Q
    (2008) The breast cancer resistance protein (Bcrp1/Abcg2) limits fetal distribution of glyburide in the pregnant mouse: an Obstetric-Fetal Pharmacology Research Unit Network and University of Washington Specialized Center of Research Study. Mol Pharmacol 73:949–959.
    OpenUrlAbstract/FREE Full Text
PreviousNext
Back to top

In this issue

Journal of Pharmacology and Experimental Therapeutics: 357 (1)
Journal of Pharmacology and Experimental Therapeutics
Vol. 357, Issue 1
1 Apr 2016
  • Table of Contents
  • Table of Contents (PDF)
  • About the Cover
  • Index by author
  • Editorial Board (PDF)
  • Front Matter (PDF)
Download PDF
Article Alerts
Sign In to Email Alerts with your Email Address
Email Article

Thank you for sharing this Journal of Pharmacology and Experimental Therapeutics article.

NOTE: We request your email address only to inform the recipient that it was you who recommended this article, and that it is not junk mail. We do not retain these email addresses.

Enter multiple addresses on separate lines or separate them with commas.
Genetic and Dietary Regulation of Glyburide Efflux by the Human Placental Breast Cancer Resistance Protein Transporter
(Your Name) has forwarded a page to you from Journal of Pharmacology and Experimental Therapeutics
(Your Name) thought you would be interested in this article in Journal of Pharmacology and Experimental Therapeutics.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Research ArticleMetabolism, Transport, and Pharmacogenomics

Genistein Reduces Placental BCRP Function and Expression

Kristin M. Bircsak, Vivek Gupta, Poi Yu Sofia Yuen, Ludwik Gorczyca, Barry I. Weinberger, Anna M. Vetrano and Lauren M. Aleksunes
Journal of Pharmacology and Experimental Therapeutics April 1, 2016, 357 (1) 103-113; DOI: https://doi.org/10.1124/jpet.115.230185

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Share
Research ArticleMetabolism, Transport, and Pharmacogenomics

Genistein Reduces Placental BCRP Function and Expression

Kristin M. Bircsak, Vivek Gupta, Poi Yu Sofia Yuen, Ludwik Gorczyca, Barry I. Weinberger, Anna M. Vetrano and Lauren M. Aleksunes
Journal of Pharmacology and Experimental Therapeutics April 1, 2016, 357 (1) 103-113; DOI: https://doi.org/10.1124/jpet.115.230185
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

  • Article
    • Visual Overview
    • Abstract
    • Introduction
    • Materials and Methods
    • Results
    • Discussion
    • Acknowledgments
    • Authorship Contributions
    • Footnotes
    • Abbreviations
    • References
  • Figures & Data
  • Info & Metrics
  • eLetters
  • PDF + SI
  • PDF

Related Articles

Cited By...

More in this TOC Section

  • HDL Mimetic 4F Modulates Aβ Distribution in Brain and Plasma
  • AOX1 Inhibition by Gefitinib, Erlotinib, and Metabolites
  • Catalytic Activity of CYP2C9 Variants
Show more Metabolism, Transport, and Pharmacogenomics

Similar Articles

  • Home
  • Alerts
Facebook   Twitter   LinkedIn   RSS

Navigate

  • Current Issue
  • Fast Forward by date
  • Fast Forward by section
  • Latest Articles
  • Archive
  • Search for Articles
  • Feedback
  • ASPET

More Information

  • About JPET
  • Editorial Board
  • Instructions to Authors
  • Submit a Manuscript
  • Customized Alerts
  • RSS Feeds
  • Subscriptions
  • Permissions
  • Terms & Conditions of Use

ASPET's Other Journals

  • Drug Metabolism and Disposition
  • Molecular Pharmacology
  • Pharmacological Reviews
  • Pharmacology Research & Perspectives
ISSN 1521-0103 (Online)

Copyright © 2021 by the American Society for Pharmacology and Experimental Therapeutics