Abstract
HC-04 cells were evaluated as an in vitro model for mechanistic study of changes in the function of hepatic CYP3A during virus infection. Similar to in vivo observations, infection with a first generation recombinant adenovirus significantly inhibited CYP3A4 catalytic activity in an isoform-specific manner. Virus (MOI 100) significantly reduced expression of the retinoid X receptor (RXR) by 30% 96 hours after infection. Cytoplasmic concentrations of the pregnane X receptor (PXR) were reduced by 50%, whereas the amount of the constitutive androstane receptor (CAR) in the nuclear fraction doubled with respect to uninfected controls. Hepatocyte nuclear factor 4α (HNF-4α) and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) were also reduced by ∼70% during infection. Virus suppressed CYP3A4 activity in the presence of the PXR agonist rifampicin and did not affect CYP3A4 activity in the presence of the CAR agonist CITCO [6-(4-chlorophenyl) imidazo[2,1-b][1,3]thiazole-5-carbaldehyde-O-(3,4-dichlorobenzyl)oxime], suggesting that virus-induced modification of PXR may be responsible for observed changes in hepatic CYP3A4. The HC-04 cell line is easy to maintain, and CYP3A4 in these cells was responsive to known inducers and suppressors. Dexamethasone (200 μM) and phenobarbital (500 μM) increased activity by 230 and 124%, whereas ketoconazole (10 μM) and lipopolysaccharide (LPS) (10 μg/ml) reduced activity by 90 and 92%, respectively. This suggests that HC-04 cells can be a valuable tool for mechanistic study of drug metabolism during infection and for routine toxicological screening of novel compounds prior to use in the clinic.
Footnotes
- Received December 19, 2013.
- Accepted April 24, 2014.
This research was supported by the National Institutes of Health National Institute of Allergy and Infectious Disease [Grant U01AI078045] (to M.A.C.).
Parts of this work were presented previously: Wonganan P, Jonsson-Schmunk K, Callahan SM, Choi JH, Croyle MA (2013). Evaluation of the HC-04 Cell Line as an In Vitro Model for Mechanistic Assessment of Changes in Hepatic Cytochrome P450 3A During Adenovirus Infection. 26th Annual meeting of the American Association of Pharmaceutical Scientists; 2013 Nov 10–14; San Antonio, TX.
Parts of this work were presented as part of a doctoral dissertation: Wonganan P (2010), Doctoral Dissertation, The University of Texas at Austin College of Pharmacy, Austin, TX.
- Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics
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