Transient transcription assays of CYP3A4 reporter activity in HepG2 and LS174T cells to determine the effects of sesamin- or rifampin-mediated activation. (a) HepG2 and (b) LS174T cells were cotransfected with a vector control (pcDNA3) or PXR expression plasmid (pcDNA3-PXR), a CYP3A4 luciferase reporter plasmid, and a pRC-CMV-β-galactosidase vector. Subsequently, the transfected cells were exposed to sesamin and/or rifampin for 24 h. The results are expressed as mean ± SD (); *; **; ***, as compared to rifampin-treated cells.