Pharmaceutical Research

, Volume 22, Issue 8, pp 1287–1293

Construction of a Functional Transporter Analysis System Using MDR1 Knockdown Caco-2 Cells

  • Tomoko Watanabe
  • Reiko Onuki
  • Shinji Yamashita
  • Kazunari Taira
  • Yuichi Sugiyama
Research Paper

DOI: 10.1007/s11095-005-5270-z

Cite this article as:
Watanabe, T., Onuki, R., Yamashita, S. et al. Pharm Res (2005) 22: 1287. doi:10.1007/s11095-005-5270-z


The efflux transporter, P-glycoprotein (P-gp), located in the brush-border membrane of intestinal absorptive cells, reduces the bioavailability of a wide range of orally administered drugs. Using P-gp inhibitors in transport experiments in Caco-2 cell monolayers is widely accepted as an efficient way to estimate the contribution of P-gp to the intestinal absorption of drugs. However, there still remain some arguments that the inhibitors might affect the function of other proteins. Multidrug resistance 1 gene (MDR1) specifically inhibited Caco-2 cells were constructed, therefore, as a better in vitro evaluation system of intestinal drug absorption.


The effective sites of RNAi were selected using siRNA libraries and single siRNAs and MDR1 stable knockdown Caco-2 cells were constructed using a tRNAval-shRNA expression vector.


In siRNA stably expressed Caco-2 cells, the expression level of MDR1 was reduced at mRNA and protein levels. Transcellular transport studies using digoxin revealed that the P-gp function was suppressed completely, similar to that in verapamil-treated cells.


MDR1 stable knockdown Caco-2 cells were successfully constructed by RNAi technology. This will consequently allow the development of a selection system for candidate drugs with improved absorption properties.

Key Words

Caco-2 cellsMDR1RNAi



multidrug resistance 1




RNA interference


short hairpin RNA


small interference RNA

Copyright information

© Springer Science + Business Media, Inc. 2005

Authors and Affiliations

  • Tomoko Watanabe
    • 1
  • Reiko Onuki
    • 1
  • Shinji Yamashita
    • 2
  • Kazunari Taira
    • 3
    • 4
  • Yuichi Sugiyama
    • 1
  1. 1.Department of Molecular Pharmacokinetics, Graduate School of Pharmaceutical SciencesThe University of TokyoBunkyo-ku, TokyoJapan
  2. 2.Department of Biopharmacy, Faculty of Pharmaceutical SciencesSetsunan UniversityHirakata, OsakaJapan
  3. 3.Department of Chemistry and Biotechnology, School of EngineeringThe University of TokyoBunkyo-ku, TokyoJapan
  4. 4.Gene Function Research CenterNational Institute of Advanced Industrial Science and Technology (AIST)TsukubaJapan