Bircsak Kristin M, Gupta Vivek, Yuen Poi Yu Sofia, Gorczyca Ludwik, Weinberger Barry I, Vetrano Anna M, Aleksunes Lauren M
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.).
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.)
J Pharmacol Exp Ther. 2016 Apr;357(1):103-13. doi: 10.1124/jpet.115.230185. Epub 2016 Feb 5.
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 (3)H-glyburide in both wild-type (WT) and C421A-BCRP HEK-expressing cells, with greater accumulation of (3)H-glyburide in cells expressing the C421A variant. In BeWo cells, exposure to genistein for 60 minutes increased the accumulation of (3)H-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.
由于乳腺癌耐药蛋白（BCRP）/ABCG2转运蛋白介导的胎盘外排作用，使得格列本脲在胎儿体内的蓄积量较低，因此它常用于治疗妊娠期糖尿病。在此，我们试图利用稳定转染的人胚肾293（HEK）细胞、人胎盘绒毛膜癌细胞BeWo细胞和人胎盘外植体，来确定饮食中的植物雌激素染料木黄酮的暴露以及ABCG2基因功能缺失多态性（C421A）的表达如何影响BCRP对格列本脲的转运。染料木黄酮在野生型（WT）和表达C421A-BCRP的HEK细胞中均竞争性抑制BCRP介导的（3）H-格列本脲转运，且在表达C421A变体的细胞中（3）H-格列本脲的蓄积量更高。在BeWo细胞中，在与饮食暴露相关的浓度下（半数抑制浓度约为180 nM），暴露于染料木黄酮60分钟可使（3）H-格列本脲的蓄积量增加30%-70%。将BeWo细胞连续暴露于染料木黄酮48小时可使BCRP mRNA和蛋白的表达降低多达40%，这损害了BCRP的转运活性。雌激素受体的药理拮抗作用减弱了染料木黄酮介导的BCRP表达下调，表明植物雌激素可能通过该激素受体途径降低BeWo细胞中的BCRP水平。有趣的是，染料木黄酮处理48小时并未改变从足月健康胎盘中分离出的外植体中BCRP蛋白的表达。这些数据表明，虽然染料木黄酮可作为BCRP介导转运的竞争性抑制剂，但其下调胎盘BCRP表达的能力可能仅发生在绒毛膜癌细胞中。总体而言，本研究提供了重要的机制数据，说明环境因素（饮食中的染料木黄酮）和常见基因变体（ABCG2，C421A）如何改变格列本脲的母胎分布。
