2021 Drug metabolism and disposition: the biological fate of chemicals
* Deconvolution of Cytochrome P450 Induction Mechanisms in HepaRG Nuclear Hormone Receptor Knockout Cells.
- Pregnane X receptor (PXR), constitutive androstane receptor (CAR), and PXR/CAR knockout (KO) HepaRG cells, as well as a PXR reporter gene assay, were used to investigate the mechanism of CYP3A4 and CYP2B6 induction by prototypical substrates and a group of compounds from the Merck KGaA oncology drug discovery pipeline. The basal and inducible gene expression of CYP3A4 and CYP2B6 of nuclear hormone receptor (NHR) KO HepaRG relative to control HepaRG was characterized. The basal expression of CYP3A4 was markedly higher in the PXR (10-fold) and CAR (11-fold) KO cell lines compared with control HepaRG, whereas inducibility was substantially lower. Inversely, basal expression of CYP3A4 in PXR/CAR double KO (dKO) was low (10-fold reduction). Basal CYP2B6 expression was high in PXR KO (9-fold) cells which showed low inducibility, whereas the basal expression remained unchanged in CAR and dKO cell lines compared with control cells. Most of the test compounds induced CYP3A4 and CYP2B6 via PXR and, to a lesser extent, via CAR. Furthermore, other non-NHR-driven induction mechanisms were implicated, either alone or in addition to NHRs. Notably, 5 of the 16 compounds (31%) that were PXR inducers in HepaRG did not activate PXR in the reporter gene assay, illustrating the limitations of this system. This study indicates that HepaRG is a highly sensitive system fit for early screening of cytochrome P450 (P450) induction in drug discovery. Furthermore, it shows the applicability of HepaRG NHR KO cells as tools to deconvolute mechanisms of P450 induction using novel compounds representative for oncology drug discovery. SIGNIFICANCE STATEMENT: This work describes the identification of induction mechanisms of CYP3A4 and CYP2B6 for an assembly of oncology drug candidates using HepaRG nuclear hormone receptor knockout and displays its advantages compared to a pregnane X receptor reporter gene assay. With this study, risk assessment of drug candidates in early drug development can be improved.
=>表現すること, 式, 表現, 表示, 言い回し, 表現法, 表情
Overview of noun expression
The noun expression has 9 senses (first 6 from tagged texts)
1. (23) expression, look, aspect, facial expression, face -- (the feelings expressed on a person's
face; "a sad expression"; "a look of triumph"; "an angry face")
2. (18) expression, manifestation, reflection, reflexion -- (expression without words; "tears are an
expression of grief"; "the pulse is a reflection of the heart's condition")
3. (15) expression, verbal expression, verbalism -- (the communication (in speech or writing) of
your beliefs or opinions; "expressions of good will"; "he helped me find verbal expression for my
ideas"; "the idea was immediate but the verbalism took hours")
4. (5) saying, expression, locution -- (a word or phrase that particular people use in particular
situations; "pardon the expression")
5. (4) formulation, expression -- (the style of expressing yourself; "he suggested a better
formulation"; "his manner of expression showed how much he cared")
6. (4) formula, expression -- (a group of symbols that make a mathematical statement)
7. expression -- ((genetics) the process of expressing a gene)
8. construction, grammatical construction, expression -- (a group of words that form a constituent
of a sentence and are considered as a single unit; "I concluded from his awkward constructions that
he was a foreigner")
9. expression -- (the act of forcing something out by squeezing or pressing; "the expression of milk
from her breast")
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