FIG. 2.

Transcriptional involvement in CYP3A4 and HCE2 induction by 8-MOP. (A) Effect of DRB on the induction of CYP3A4 and HCE2. Huh7 cells were treated for 30 h with DMSO (0.1%), 8-MOP (25μM), or RIF (25μM). The treatment with 8-MOP was performed in the presence or absence of DRB (50μM). Total RNA was isolated and analyzed for the expression of CYP3A4, HCE2, or GAPDH. The PCR cycles were 35 for CYP3A4, 30 for HCE2, and 22 for GAPDH. (B) Activation of CYP3A4 and HCE2 promoter reporter. Huh7 cells were transiently transfected by LipofectAMINE with a mixture containing 100 ng of reporter and 10 ng of the null-Renilla luciferase plasmid. After 12 h incubation, the transfected cells were treated with 8-MOP (25μM) or the same volume of DMSO (0.1%) for 24 h. Luciferase activities were determined with a Dual-Luciferase Reporter Assay System, and the reporter activity was normalized based on the Renilla luminescence signal. The ratio of treatment over DMSO served as fold induction. Three independent experiments were performed, and the data are expressed as mean ± SD. *Significantly different from DMSO-treated cells according to t-test (p < 0.05).