title: Multiple SLC and ABC Transporters Contribute to the Placental Transfer of Entecavir.
abstract: Entecavir (ETV), a nucleoside analog with high efficacy against hepatitis B virus, is recommended as a first-line antiviral drug for the treatment of chronic hepatitis B. However, scant information is available on the use of ETV in pregnancy. To better understand the safety of ETV in pregnant women, we aimed to demonstrate whether ETV could permeate placental barrier and the underlying mechanism. Our study showed that small amount of ETV could permeate across placenta in mice. ETV accumulation in activated or nonactivated BeWo cells (treated with or without forskolin) was sharply reduced in the presence of 100 µM of adenosine, cytidine, and in Na+free medium, indicating that nucleoside transporters possibly mediate the uptake of ETV. Furthermore, ETV was proved to be a substrate of concentrative nucleoside transporter (CNT) 2 and CNT3, of organic cation transporter (OCT) 3, and of breast cancer resistance protein (BCRP) using transfected cells expressing respective transporters. The inhibition of ETV uptake in primary human trophoblast cells further confirmed that equilibrative nucleoside transporter (ENT) 1/2, CNT2/3, OCT3, and organic cation/carnitine transporter (OCTN) 2 might be involved in ETV transfer in human placenta. Therefore, ETV uptake from maternal circulation to trophoblast cells was possibly transported by CNT2/3, ENT1/2, and OCTN2, whereas ETV efflux from trophoblast cells to fetal circulation was mediated by OCT3, and efflux from trophoblast cells to maternal circulation might be mediated by BCRP, multidrug resistance-associated protein 2, and P-glycoprotein. The information obtained in the present study may provide a basis for the use of ETV in pregnancy.
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (Z.M., X.Y., T.J., M.B., S.Z., H.J.); and Women's Hospital School of Medicine Zhejiang University, Hangzhou, China (C.Z., D.S.).
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Ma
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (Z.M., X.Y., T.J., M.B., S.Z., H.J.); and Women's Hospital School of Medicine Zhejiang University, Hangzhou, China (C.Z., D.S.).
authors.forename: Xi
authors.initials: X
authors.lastname: Yang
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (Z.M., X.Y., T.J., M.B., S.Z., H.J.); and Women's Hospital School of Medicine Zhejiang University, Hangzhou, China (C.Z., D.S.).
authors.forename: Ting
authors.initials: T
authors.lastname: Jiang
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (Z.M., X.Y., T.J., M.B., S.Z., H.J.); and Women's Hospital School of Medicine Zhejiang University, Hangzhou, China (C.Z., D.S.).
authors.forename: Mengru
authors.initials: M
authors.lastname: Bai
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (Z.M., X.Y., T.J., M.B., S.Z., H.J.); and Women's Hospital School of Medicine Zhejiang University, Hangzhou, China (C.Z., D.S.).
authors.forename: Caihong
authors.initials: C
authors.lastname: Zheng
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (Z.M., X.Y., T.J., M.B., S.Z., H.J.); and Women's Hospital School of Medicine Zhejiang University, Hangzhou, China (C.Z., D.S.).
authors.forename: Su
authors.initials: S
authors.lastname: Zeng
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (Z.M., X.Y., T.J., M.B., S.Z., H.J.); and Women's Hospital School of Medicine Zhejiang University, Hangzhou, China (C.Z., D.S.).
authors.forename: Dongli
authors.initials: D
authors.lastname: Sun
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (Z.M., X.Y., T.J., M.B., S.Z., H.J.); and Women's Hospital School of Medicine Zhejiang University, Hangzhou, China (C.Z., D.S.) hdjiang@zju.edu.cn Sundongli@zju.edu.cn.
authors.forename: Huidi
authors.initials: H
authors.lastname: Jiang
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000998:Antiviral Agents / Q000378:metabolism / Q000493:pharmacokinetics*; D045744:Cell Line, Tumor; D005260:Female; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics; D006801:Humans; D051379:Mice; D008813:Mice, Inbred ICR; D010539:Permeability; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D061251:Primary Cell Culture; D000070590:Solute Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D014162:Transfection; D014327:Trophoblasts / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D000998:Antiviral Agents; D000070590:Solute Carrier Proteins; C413685:entecavir; D006147:Guanine