Assessment of the role of nucleoside transporters, P-glycoprotein, breast cancer resistance protein, and multidrug resistance-associated protein 2 in the placental transport of entecavir using in vitro, ex vivo, and in situ methods.

The nucleoside analog entecavir (ETV) is a first-line pharmacotherapy for chronic hepatitis B in adult and pediatric patients. However, due to insufficient data on placental transfer and its effects on pregnancy, ETV administration is not recommended for women after conception. To expand knowledge of safety, we focused on evaluating the contribution of nucleoside transporters (NBMPR sensitive ENTs and Na dependent CNTs) and efflux transporters, P-glycoprotein (ABCB1), breast cancer resistance protein (ABCG2), and multidrug resistance-associated transporter 2 (ABCC2), to the placental kinetics of ETV.

S-(4-Nitrobenzyl)-6-thioinosine (NBMPR) is Not a Selective Inhibitor of Equilibrative Nucleoside Transporters but Also Blocks Efflux Activity of Breast Cancer Resistance Protein.

Purpose: S-(4-Nitrobenzyl)-6-thioinosine (NBMPR) is routinely used at concentrations of 0.10 μM and 0.10 mM to specifically inhibit transport of nucleosides mediated by equilibrative nucleoside transporters 1 (ENT1) and 2 (ENT2), respectively.

Are /ENT1, and miR-21 Reliable Prognostic Biomarkers in Patients with Resected Pancreatic Adenocarcinoma Treated with Adjuvant Gemcitabine Monotherapy?

Evidence on equilibrative nucleoside transporter 1 (ENT1) and microRNA-21 (miR‑21) is not yet sufficiently convincing to consider them as prognostic biomarkers for patients with pancreatic ductal adenocarcinoma (PDAC). Here, we investigated the prognostic value of /ENT1, miR-21, and neurogenic locus homolog protein 3 gene () in a well-defined cohort of resected patients treated with adjuvant gemcitabine chemotherapy ( = 69). Using a combination of gene expression quantification in microdissected tissue, immunohistochemistry, and univariate/multivariate statistical analyses we did not confirm association of /ENT1 and with improved disease-specific survival (DSS).

Transport of ribavirin across the rat and human placental barrier: Roles of nucleoside and ATP-binding cassette drug efflux transporters.

Ribavirin is a broad-spectrum nucleoside-derived antiviral drug used in combination pharmacotherapy treatment of hepatitis C virus infection. Current evidence indicates that ribavirin-associated teratogenicity is not significant in humans, but more information about the developmental toxicity and mechanisms involved in ribavirin placental kinetics is required to assure its safe use in pregnancy. Thus, we have investigated potential roles of equilibrative nucleoside transporters (ENTs, SLC29A), Na-dependent influx-mediating concentrative nucleoside transporters (CNTs, SLC28A), and ATP-binding cassette (ABC) efflux pumps, in ribavirin placental pharmacokinetics.

Equilibrative Nucleoside Transporter 1 (ENT1, ) Facilitates Transfer of the Antiretroviral Drug Abacavir across the Placenta.

Abacavir is a preferred antiretroviral drug for preventing mother-to-child human immunodeficiency virus transmission; however, mechanisms of its placental transfer have not been satisfactorily described to date. Because abacavir is a nucleoside-derived drug, we hypothesized that the nucleoside transporters, equilibrative nucleoside transporters (ENTs, ) and/or Na-dependent concentrative nucleoside transporters (CNTs, ), may play a role in its passage across the placenta. To test this hypothesis, we performed uptake experiments using the choriocarcinoma-derived BeWo cell line, human fresh villous fragments, and microvillous plasma membrane (MVM) vesicles.