Assessment of Induction of Cytochrome P450 by NO-1886 (Ibrolipim), a Lipoprotein Lipase-Promoting Agent, in Primary Cultures of Human Hepatocytes and in Female Rat Liver

Abstract

The mRNA levels of human cytochrome P450 (CYP)2Cs and CYP3As in primary cultures of freshly isolated human hepatocytes were assessed after exposure to NO-1886 and rifampicin, a typical inducer of CYP3As. mRNA levels were analyzed by real-time RT-PCR using an ABI PRISM 7700 Sequence Detector system. Exposure to NO-1886 for 24 hr at a concentration of less than 10 microM showed only a tendency to reduce or increase the expression levels of CYP2C8, CYP2C9, CYP2C19, CYP3A4, or CYP3A5 mRNA. A higher concentration (50 microM) of NO-1886 induced an increase in CYP2C8 mRNA and a decrease in CYP2C19 mRNA, and these changes continued after additional culture for 24 hr in fresh medium without NO-1886. The expression level of CYP3A4 mRNA after exposure to NO-1886 for 24 hr at 50 microM was about twice that in controls. Following additional culture for 24 hr in fresh medium without NO-1886, the expression of CYP3A4 mRNA was comparable to that in controls. On the other hand, the expression levels of CYP2C9 and CYP3A5 mRNA showed small and variable changes in each donor even at a high concentration (50 microM) of NO-1886. Furthermore, the pharmacokinetics of NO-1886 during repeated oral administration for 14 days was studied in female rats. The pharmacokinetic parameters of NO-1886 were nearly the same on days 1, 7, and 14 of repeated administration. The hepatic microsomal content of CYP isoforms was not affected by repeated administration for 7 days at a dose of 1 to 30 mg/kg in female rats, although the total CYP content was increased at a dose of 30 mg/kg. The expression levels of CYP1A2, CYP2B2, CYP2C12, and CYP2E1 mRNA in primary cultures of rat hepatocytes were not affected by exposure to NO-1886 at 2, 10, or 50 microM. The expression levels of CYP3A1 mRNA in primary cultures of rat hepatocytes were not affected by exposure to NO-1886 at 2 or 10 microM, but were increased, with large individual variation, by exposure at 50 microM. The mRNA expression levels in rat hepatocytes exposed to concentrations comparable to free plasma levels did not change significantly, which was consistent with the equivalence in the in vivo plasma concentrations observed on days 1 and 14 of repeated administration. These results suggest that repeated administration of NO-1886 at clinical doses does not significantly affect the expression levels of CYP isoforms in human liver, although the mRNA levels of the CYP isoforms involved in the metabolism of NO-1886 were increased by exposure to higher concentrations of NO-1886 in human hepatocytes in vitro.

Tissue-specific mRNA Expression Profiles of Human Solute Carrier Transporter Superfamilies

“…Table 5 lists the references for our studies concerning the measurement of these human mRNA targets by the TaqMan method. We have adopted the one-step RT-PCR method to measure the expression levels of every target gene related to the gene induction of drug-metabolizing enzymes in primary cultures of human hepatocytes 59,61,65,[67][68][69][70][71] and to the tissue-specific profiles of mRNA expression in human tissues, as described in our previous studies 9, [12][13][14]60,72) and the present study.…”

Secretion of Albumin and Induction of CYP1A2 and CYP3A4 in Novel Three-dimensional Culture System for Human Hepatocytes using Micro-space Plate

“…10) Moreover, we confirmed that the induction of drug-metabolizing enzyme and transporter mRNAs could be evaluated after 24 h of exposure to these inducers. 4,12,20) The changes in CYP1A2 mRNA levels induced by exposure to Ome in primary cultures of cryopreserved human hepatocytes using traditional and micro-space plates are shown in Figure 7. On the traditional plate cultures, the level of CYP1A2 mRNA in hepatocytes from Lots 100, LMP and VUA increased by 74-, 25-and 101-fold, respectively, after exposure to 50 mM Ome compared with that in 0.1% DMSO-treated controls, while on micro-space plate cultures, the level increased by 34-, 32-and 41-fold, respectively.…”

Evaluation of Induction Potency of New Drug Candidates on CYP1A2 and CYP3A4 using Real-Time One-Step RT-PCR in Primary Cultures of Cryopreserved Human Hepatocytes

“…22) We previously found that after exposure to 50 mM NO-1886 in primary cultures of freshly isolated and cryopreserved human hepatocytes, the level of CYP3A4 mRNA significantly increased by about 2-to 3.6-fold, while that of CYP1A2 increased by 2-fold or less, compared to the 0.1% DMSO-treated controls. 23,24) We evaluated the levels of gene expression of CYP1A2 and CYP3A4 in primary cultures of cryopreserved human hepatocytes after exposure to eight NO-1886 derivatives (A, B, C, D, E, F, G and H) (Figs. 3 and 4).…”