The functional influences of common ABCB1 genetic variants on the inhibition of P-glycoprotein by Antrodia cinnamomea extracts

PLoS One. 2014 Feb 25;9(2):e89622. doi: 10.1371/journal.pone.0089622. eCollection 2014.

Abstract

Antrodia cinnamomea is a traditional healthy food that has been demonstrated to possess anti-inflammatory, antioxidative, and anticacer effects. The purpose of this study was to evaluate whether the ethanolic extract of A. cinnamomea (EEAC) can affect the efflux function of P-glycoprotein (P-gp) and the effect of ABCB1 genetic variants on the interaction between EEAC and P-gp. To investigate the mechanism of this interaction, Flp-In™-293 cells stably transfected with various genotypes of human P-gp were established and the expression of P-gp was confirmed by Western blot. The results of the rhodamine 123 efflux assay demonstrated that EEAC efficiently inhibited wild-type P-gp function at an IC50 concentration of 1.51 ± 0.08 µg/mL through non-competitive inhibition. The IC50 concentrations for variant-type 1236T-2677T-3435T P-gp and variant-type 1236T-2677A-3435T P-gp were 5.56 ± 0.49 µg/mL and 3.33±0.67 µg/mL, respectively. In addition, the inhibition kinetics of EEAC also changed to uncompetitive inhibition in variant-type 1236T-2677A-3435T P-gp. The ATPase assay revealed that EEAC was an ATPase stimulator and was capable of reducing verapamil-induced ATPase levels. These results indicate that EEAC may be a potent P-gp inhibitor and higher dosages may be required in subjects carrying variant-types P-gp. Further studies are required to translate this basic knowledge into clinical applications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B / antagonists & inhibitors
  • ATP Binding Cassette Transporter, Subfamily B / genetics
  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / antagonists & inhibitors*
  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / genetics*
  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / metabolism
  • Adenosine Triphosphatases / metabolism
  • Antrodia / chemistry*
  • Genetic Variation
  • HEK293 Cells
  • Humans
  • Plant Extracts / pharmacology*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rhodamine 123 / metabolism

Substances

  • ABCB1 protein, human
  • ATP Binding Cassette Transporter, Subfamily B
  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Plant Extracts
  • RNA, Messenger
  • Rhodamine 123
  • Adenosine Triphosphatases

Grant support

This work was supported by grants from the National Science Council in Taiwan (NSC 102-2320-B-039-016), Taiwan Department of Health Clinical Trial and Research Center of Excellence (DOH102-TD-B-111-004), and the National Health Research Institutes in Taiwan (NHRI-102A1-PDCO-1312141). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.