Differential UGT1A1 induction by chrysin in primary human hepatocytes and HepG2 Cells

Division of Drug Delivery and Disposition, School of Pharmacy, CB 7360, Kerr Hall, Room 2319, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7360, USA.
Journal of Pharmacology and Experimental Therapeutics (Impact Factor: 3.97). 01/2006; 315(3):1256-64. DOI: 10.1124/jpet.105.090795
Source: PubMed


Chrysin, a dietary flavonoid, has been shown to markedly induce UGT1A1 expression and activity in HepG2 and Caco-2 cell lines; thus, it has been suggested to have clinical utility in the treatment of UGT1A1-mediated deficiencies, such as unconjugated hyperbilirubinemia or the prevention of 7-ethyl-10-hydroxycamptothecin (SN-38) toxicity. However, little is known about its induction potential in a more physiologically relevant model system, such as primary hepatocyte culture. In this study, induction of UGT1A1 expression (mRNA, protein, and activity) was investigated in primary human hepatocyte cultures after treatment with chrysin and other prototypical inducers. Endogenous nuclear receptor-mediated UGT1A1 induction was studied using transient transfection reporter assays in primary human hepatocytes and HepG2 cells. Results indicated that induction of UGT1A1 expression was minimal in human hepatocytes treated with chrysin compared with that in HepG2 cells (1.2-versus 11-fold, respectively). Subsequent experiments to determine whether the differential response was due to its metabolic stability revealed strikingly different elimination rate constants between the two cell systems (half-life of 13 min in human hepatocytes versus 122 min in HepG2 cell suspensions). Further study demonstrated that UGT1A1 mRNA expression could be induced in human hepatocyte cultures by either increasing the chrysin dosing frequency or by modulating chrysin metabolism, suggesting that the differential induction observed in hepatocytes and HepG2 cells was due to differences in the metabolic clearance of chrysin. In conclusion, this study suggests that the metabolic stability of chrysin likely would limit its ability to induce UGT1A1 in vivo.

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    • "Benchmark dose values obtained for individual genes, and signaling pathways were used to derive REP values that were then compared with the published 2005 WHO TEF values. The cell model employed, primary cultures of rat hepatocytes, is generally thought to better mimic in vivo hepatocyte function than commonly used immortalized cells (Guillouzo and Guguen- Guillouzo, 2008; LeCluyse et al., 1999; Smith et al., 2005). This makes primary hepatocytes a good model for studying a large number of chemical concentrations on hepatic transcription activity. "
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    Toxicological Sciences 12/2013; 136(2):595-604. DOI:10.1093/toxsci/kft203 · 3.85 Impact Factor
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    • "effects, better alternative to it includes, dietary flavones which do not have problem of side effects and are considered suitable to treat hyperbilirubinemia [12] [13]. One of the important flavonoids belonging to this class is chrysin (5,7-dihydroxyflavone); chrysin has been shown to induce UGT1A1 expression in liver cells and greatly enhanced bilirubin glucuronidation in HepG2 cells [14] [15]. Moreover, there are convincing evidences on chrysin's ability to induce UGT1A1 expression in tissue culture models [16]. "
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    Biochemical pharmacology 07/2011; 82(9):1186-97. DOI:10.1016/j.bcp.2011.07.069 · 5.01 Impact Factor
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    • "Total RNA was isolated using the RNeasy Mini Kit (QIAGEN, Valencia, CA) and reverse-transcribed using the High-Capacity cDNA Archive Kit (Applied Biosystems) per manufacturers' instructions. Primers and probes for CYP2B6, CYP3A4, UGT1A1, and MDR1 genes (Table 1) were designed using Primer Express version 2.0 (Applied Biosystems) and entered into the National Center for Biotechnology Information BLAST to ensure specificity as described previously (Maglich et al., 2002; Smith et al., 2005; Faucette et al., 2007; Li et al., 2008). The mRNA expression of CYP2B6, CYP3A4, UGT1A1, and MDR1 was normalized against that of human ␤-actin, which was detected using a predeveloped primer/probe mixture (Applied Biosystems). "
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