Anti-HIV and Anti-Hepatitis C Virus Drugs Inhibit P-Glycoprotein Efflux Activity in Caco-2 Cells and Precision-Cut Rat and Human Intestinal Slices

Abstract

P-glycoprotein (ABCB1), an ATP-binding-cassette efflux transporter, limits intestinal absorption of its substrates and is a common site of drug-drug interactions (DDIs). ABCB1 has been suggested to interact with many antivirals used to treat HIV and/or chronic hepatitis C virus (HCV) infections. Using bidirectional transport experiments in Caco-2 cells and a recently established ex vivo model of accumulation in precision-cut intestinal slices (PCIS) prepared from rat ileum or human jejunum, we evaluated the potential of anti-HIV and anti-HCV antivirals to inhibit intestinal ABCB1. Lopinavir, ritonavir, saquinavir, atazanavir, maraviroc, ledipasvir, and daclatasvir inhibited the efflux of a model ABCB1 substrate, rhodamine 123 (RHD123), in Caco-2 cells and rat-derived PCIS. Lopinavir, ritonavir, saquinavir, and atazanavir also significantly inhibited RHD123 efflux in human-derived PCIS, while possible interindividual variability was observed in the inhibition of intestinal ABCB1 by maraviroc, ledipasvir, and daclatasvir. Abacavir, zidovudine, tenofovir disoproxil fumarate, etravirine, and rilpivirine did not inhibit intestinal ABCB1. In conclusion, using recently established ex vivo methods for measuring drug accumulation in rat- and human-derived PCIS, we have demonstrated that some antivirals have a high potential for DDIs on intestinal ABCB1. Our data help clarify the molecular mechanisms responsible for reported increases in the bioavailability of ABCB1 substrates, including antivirals and drugs prescribed to treat comorbidity. These results could help guide the selection of combination pharmacotherapies and/or suitable dosing schemes for patients infected with HIV and/or HCV.

Keywords: Caco-2 cells; P-glycoprotein; antiviral drugs; drug-drug interactions; intestinal absorption; precision-cut intestinal slices; rhodamine 123.

FIG 1

Inhibition caused by antivirals tested at the concentrations causing the most significant effect on bidirectional transport of RHD123 (1 μM) across a monolayer of Caco-2 cells. (A) Calculated values of rP_app for RHD123 transport in the absence of inhibitors (dotted line) and in the presence (columns) of antivirals. (B) Multiple comparison of the inhibitory effects of antivirals. Data are presented as means ± SD (n = 3). Statistical analysis was performed using Student’s two-tailed t test (n = 3): n.s., not significant; *, P < 0.05; **, P < 0.01.

FIG 2

Inhibition of ABCB1-controled RHD123 efflux caused by antivirals tested at the concentrations causing the most significant increase in RHD123 (10 μM) accumulation over 2 h in rat PCIS. (A) Tissue RHD123 concentrations in the absence of inhibitors (dotted line) and in the presence of antivirals (columns). (B) Multiple comparison of inhibitory effects of antivirals. Data are presented as medians with interquartile ranges (n = 3). Statistical analysis was performed using the nonparametric Mann-Whitney test: n.s., not significant; *, P < 0.05.

FIG 3

ATP content of the rat ileum (n = 3) (A) and human jejunum (n = 5) (B) after 2.5-h incubation in the presence of the studied antivirals at the highest concentrations used. Data are presented as medians with interquartile ranges. Statistical significance was assessed by nonparametric Kruskal-Wallis analysis followed by Dunn’s test. No statistically significant differences were found. TDF, tenofovir disoproxil fumarate.