Characterisation of ATP-binding cassette (ABC) transporters in bronchial epithelial cell culture models

Hutter, Victoria (2012) Characterisation of ATP-binding cassette (ABC) transporters in bronchial epithelial cell culture models. PhD thesis, University of Nottingham.

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Abstract

In vitro epithelial cell cultures are increasingly used to model drug permeability, as predictive tools for absorption in humans. Medical regulatory agencies recommend in vitro permeability screening for biopharmaceutical classification of novel therapeutic compounds, and recently published guidelines on investigating interactions of novel therapeutic compounds with clinically relevant transporters. The expression and functionality of drug transporters in the lung is poorly characterised, and insufficient to allow detailed understanding of drug-transporter interactions in the airways. Additionally, as human in vitro permeability is used to predict absorption from rat in vivo, a rat bronchial epithelium in vitro cell line would aid the understanding of interspecies differences in transporter-mediated drug trafficking.

This thesis investigates the morphological and physiological barrier properties of Calu-3, normal human bronchial epithelial (NHBE) cell layers and rat airway epithelial cell (RL-65) cultures. The morphology and barrier integrity of RL-65 layers were shown to be in agreement with existing human bronchial epithelial cell models after culture for 8 days at air-liquid interface. The expression of >30 ABC, SLC and SLCO transporters in human models was in general agreement with published expression levels in human lungs. MDR1 functionality was investigated, and whilst no asymmetric transport of 3H-digoxin was observed in RL-65 cell layers, net secretory transport was observed for Calu-3 cell layers at both low (25-30) and high (45-45) passage number and for some batches of NHBE cell layers. Chemical, metabolic and biological inhibitors were employed to evaluate MDR1 contribution to 3H-digoxin trafficking, however the exact transporter(s) involved could not be determined. Whilst MDR1 functionality could not be ruled out, results suggest that it is unlikely to be the main transporter involved in 3H-digoxin trafficking in the bronchial epithelium. These studies have highlighted the need for more specific approaches to investigating transporter functionality in in vitro systems.

Item Type:Thesis (PhD)
Supervisors:Bosquillon, C.
Pritchard, D.I.
Uncontrolled Keywords:ATP-binding cassette transporters, in vitro, epithelial cell cultures
Faculties/Schools:UK Campuses > Faculty of Science > School of Pharmacy
ID Code:2442
Deposited By:Victoria Hutter
Deposited On:17 Sep 2012 11:51
Last Modified:17 Sep 2012 11:51

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