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CYP3A4 inducible model for in vitro analysis of human drug metabolism using a bioartificial liver
Author(s) -
Iwahori Tohru,
Matsuura Tomokazu,
Maehashi Haruka,
Sugo Ken,
Saito Masaya,
Hosokawa Masakiyo,
Chiba Kan,
Masaki Takahiro,
Aizaki Hideki,
Ohkawa Kiyoshi,
Suzuki Tetsuro
Publication year - 2003
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1053/jhep.2003.50094
Subject(s) - cyp3a4 , bioartificial liver device , drug metabolism , in vitro , human liver , drug , pharmacology , medicine , chemistry , metabolism , cytochrome p450 , biochemistry , hepatocyte
CYP3A is responsible for approximately 50% of the therapeutic drug‐metabolizing activity in the liver. The present study was undertaken to establish the CYP3A4 inducible model for analysis of human drug metabolism using a bioartificial liver composed of the functional hepatocellular carcinoma cell (HCC) line FLC‐5. A radial‐flow bioreactor (RFB), which is a carrier‐filled type bioreactor, was used for 3‐dimensional perfusion culture of FLC‐5 cells. The CYP3A4 messenger RNA (mRNA) expression level 48 hours after rifampicin treatment in the RBF was approximately 100 times higher than that in a monolayer culture. Western blot analysis also demonstrated an increase in expression of the CYP3A protein. When testosterone, a substrate for CYP3A4, was added to the rifampicin‐treated cell culture, 6β‐hydroxy testosterone as a metabolite was formed. Electrophoretic mobility shift assay (EMSA) with a CYP3A4 ER6 probe demonstrated that relatively high molecular weight complex containing pregnane X receptor (PXR)/retinoid X receptorα(RXRα), compared with that in the monolayer culture, is possibly generated in the RFB culture of FLC‐5 treated with rifampicin. Similarly, the assay with a probe of HNF‐4α‐binding motif indicated the formation of a large protein complex in the RFB culture. Because it is known that PXR transactivates CYP3A4 gene via its response element and expression of PXR is regulated by HNF‐4α, the large complexes binding to response elements of PXR or HNF‐4α in the RFB culture may contribute to up‐regulation of CYP3A4 mRNA. In conclusion, the bioartificial liver composed of human functional HCC cell line was useful in studying drug interactions during induction of human CYP3A4.