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An Improved Cell Culture Model Based on 2/4/A1 Cell Monolayers for Studies of Intestinal Drug Transport
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Developmental Neuroscience.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
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2003 (English)In: Pharmaceutical research, ISSN 0724-8741, E-ISSN 1573-904X, Vol. 20, no 3, 373-381 p.Article in journal (Refereed) Published
Abstract [en]


To improve the viability of the 2/4/A1 cell culture model and to investigate different routes of drug transport in this cell line.


Two approaches were taken to decrease apoptosis. First, rat intestinal 2/4/A1 cells were transfected to overexpress the antiapoptotic protein Bcl-2. Second. normal 2/4/A1 cells were cultivated under conditions that stimulate differentiation and limit apoptosis. The monolayer integrity was investigated by transepithelial electrical resistance, permeability, and microscopy. The expression of drug transporters was investigated by RT-PCR, and transport function was assessed using specific markers.


Normal 2/4/A1 cells died by apoptosis at 39°C. Bcl-2-expressing 2/4/A1 cells were viable but adopted a morphology of less-differentiated epithelial cells. Optimization of the culture conditions for 2/4/A1 cells inhibited cell death. The integrity was comparable to that of the human jejunum (50 Ω × cm2), making this approach preferable to Bcl-2 overexpression. Transcriptional analysis showed that some (e.g., MDR1), but not all (e.g., PepT1), transporters were found in 2/4/A1 cells. Studies using substrates for PepT1, P-gp, MRP2, and BCRP showed that none of the transporters were functional in 2/4/A1.


The improved culture procedure will facilitate the use of 2/4/A1 cells. 2/4/A1 lack several transporters, which makes them a promising alternative to Caco-2 cells and artificial membranes in studies of passive drug transport.

Place, publisher, year, edition, pages
2003. Vol. 20, no 3, 373-381 p.
National Category
Cell and Molecular Biology
URN: urn:nbn:se:uu:diva-90306DOI: 10.1023/A:1022643802296PubMedID: 12669956OAI: oai:DiVA.org:uu-90306DiVA: diva2:162613
Available from: 2003-04-08 Created: 2003-04-08 Last updated: 2012-03-08Bibliographically approved
In thesis
1. New Approaches to Studies of Paracellular Drug Transport in Intestinal Epithelial Cell Monolayers
Open this publication in new window or tab >>New Approaches to Studies of Paracellular Drug Transport in Intestinal Epithelial Cell Monolayers
2003 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Studies of intestinal drug permeability have traditionally been performed in the colon-derived Caco-2 cell model. However, the permeability of these cell monolayers resembles that of the colon rather than that of the small intestine, which is the major site of drug absorption following oral administration. One aim of this thesis was therefore to develop a new cell culture model that mimics the permeability of the small intestine. 2/4/A1 cells are conditionally immortalized with a temperature sensitive mutant of SV40T. These cells proliferate and form multilayers at 33°C. At cultivation temperatures of 37 – 39°C, they stop proliferating and form monolayers. 2/4/A1 cells cultivated on permeable supports expressed functional tight junctions. The barrier properties of the tight junctions such as transepithelial electrical resistance and permeability to hydrophilic markers resembled those of the human small intestine in vivo. These cells lacked functional expression of drug transport proteins and can therefore be used as a model to study passive drug permeability unbiased by active transport. The permeability to diverse sets of drugs in 2/4/A1 was comparable to that of the human jejunum for both incompletely and completely absorbed drugs, and the prediction of human intestinal permeability was better in 2/4/A1 than in Caco-2 for incompletely absorbed drugs. The small intestinal-like paracellular permeability of 2/4/A1 thus enables better predictions of drug permeability in the small intestine than does Caco-2.

The studies of the paracellular route and its importance for intestinal drug permeability was also in focus in the second part of this thesis, in which a new principle for tight junction modulation was developed, based on the primary structure of the extracellular tight junction protein occludin. Peptides corresponding to the N-terminus of the first extracellular loop increased the permeability of the tight junctions, but lacked apical effect. This problem was solved by conjugation of one peptide to a lipoamino acid, resulting in two diastereomers with different effects. The L-isomer had a sustained apical effect, while that of the D-isomer was transient. In conclusion, conjugated occludin peptides constitute a new class of tight junction modulators that can enhance the tight junction permeability.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2003. 66 p.
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy, ISSN 0282-7484 ; 285
Pharmaceutics, intestinal epithelium, tight junctions, cell culture, Galenisk farmaci
National Category
Pharmaceutical Sciences
Research subject
urn:nbn:se:uu:diva-3388 (URN)91-554-5582-4 (ISBN)
Public defence
2003-04-29, B41, Uppsala Biomedical Centre, Uppsala, 13:00
Available from: 2003-04-08 Created: 2003-04-08Bibliographically approved

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