Quantitative analysis of constitutive and inducible CYPs mRNA expression in the HepG2 cell line using reverse transcription-competitive PCR

Drug interactions which affect drug metabolism are of clinical importance. It is, however, difficult to estimate drug interactions in human from resul ts obtained in animal experiments. In our previous study, we demonstrated t hat a combination of the HepG2 cell line and semiquantitative reverse trans cription-PCR (RT-PCR) could be used to evaluate the degree of CYP3A mRNA in duction by various drugs. Using an RT-competitive PCR (RT-cPCR) with beta-a ctin as the standard in this study, the constitutive and rifampicin (RFP)-i nduced expression of CYP3A4, CYP2C9, CYP2E1, and CYPA2 mRNA in the HepG2 ce lls could be quantitatively and reproducibly determined. 120 h-treatment of HepG2 cells with 50 mu mol/1 RFP induced maximally 8.4- and 6.0-fold the e xpression of CYP3A4 and CYP2C9 mRNA respectively in comparison with untreat ed cells. On the other hand, mRNA level in CYP2E1 and CYP1A2 was not signif icantly changed by 50 mu mol/l RFP after 24 to 120 h, To our knowledge, we report for the first time quantitative profiles of CYPs mRNA in HepG2 cells . This study demonstrates the efficiency of a combination of HepG2 cells an d RT-cPCR in the evaluation of CYPs mRNA-induction by drugs. (C) 2000 Acade mic Press.