Characterization of in vitro model based on primary culture of human mammary epithelial cells (hMECs): barrier integrity and functionality of transport routes.

This data set contains results related to the characterization of an appropriate in vitro model for the human blood milk barrier. The aim of the present study was to develop and characterize a human cell-based in vitro model capable of quantifying transfer of xenobiotics across the blood milk barrier. In the present study, both primary mammary epithelial cells (hMECs) and immortalized cell lines (MCF-7, MCF-10A and PMC42-LA) were evaluated for this purpose. The results (transepithelial electrical resistance and sodium fluorescein leakage) showed that hMECs formed a tight barrier after +/- 35 days of culture on transwell inserts in the presence of 10 % Fetal bovine serum (FBS). Indeed, epithelial morphology and presence of tight junctions was confirmed in the model. In the present study, the human cell lines did not form a tight barrier in a reproducible manner under the evaluated culture conditions (Monolayer_integrity_cell_models.ods). In addition, primary cells are the most biorelevant model. Therefore, hMECs were suggested as appropriate model for the human blood milk barrier. Furthermore, the apparent permeability of probe substrates for different transport routes were evaluated in three independent experiments (Permeability_L016.ods, Permeability_L018.ods, Permeability_L021.ods). Probe substrates were fexofenadine hydrochlode for P-glycoprotein, CDFDA for multidrug resistance-associated protein (MRP2/3, ABCC2/3), sulfasalazine for breast cancer resistance protein (BCRP, ABCG2), methotrexate hydrate for organic anion Transporter (OAT, SLC22A6/7/8/9) function, atenolol for paracellular transport, propranolol hydrochloride for passive transcellular transport, and metformin hydrochloride for organic cation transporter (OCT, SLC22A1/2/3). The results show that the model differentiates between the paracellular and transcellular transport route. However, the probe substrates used in the current study suggest limited function of carrier-mediated transport routes (OCT, OAT, P-gp, MRP and BCRP) in the hMECs in vitro model. The integrity of the monolayer was confirmed after the expeirments by measurement of the transepithelial electrical resistance and sodium fluorescien leakage. These results were partly in agreement with mRNA array data also generated for the current in vitro model. Altough future efforts should further clarify the role of membrane transporters, the hMECs in vitro model shows potential to evaluate the permeability of medicines across the blood-milk barrier. Project Info: ConcePTION (Building an ecosystem for better monitoring and communicating safety of medicines use in pregnancy and breastfeeding: validated and regulatory endorsed workflows for fast, optimised evidence generation), funded by European Union, Horizon 2020 Programme (call H2020-JTI-IMI2-2017-13-two-stage). Grant Agreement num. 821520; https://www.imi-conception.eu/. Nina Nauwelaerts received a PhD scholarship by Research-Foundation-Flanders (1S50721N).