PT  - JOURNAL ARTICLE
AU  - Anshul Gupta
AU  - Ganesh M. Mugundu
AU  - Pankaj B. Desai
AU  - Kenneth E. Thummel
AU  - Jashvant D. Unadkat
TI  - Intestinal Human Colon Adenocarcinoma Cell Line LS180 Is an Excellent Model to Study Pregnane X Receptor, but Not Constitutive Androstane Receptor, Mediated CYP3A4 and Multidrug Resistance Transporter 1 Induction: Studies with Anti-Human Immunodeficiency Virus Protease Inhibitors
AID  - 10.1124/dmd.107.018689
DP  - 2008 Jun 01
TA  - Drug Metabolism and Disposition
PG  - 1172--1180
VI  - 36
IP  - 6
4099  - http://dmd.aspetjournals.org/content/36/6/1172.short
4100  - http://dmd.aspetjournals.org/content/36/6/1172.full
SO  - Drug Metab Dispos2008 Jun 01; 36
AB  - Lack of an established cell line model to study induction of cytochromes P450 (P450s) and drug transporters poses a challenge in predicting in vivo drug-drug interactions. Although not well characterized, LS180 cells could be an excellent cell line to study induction of P450s and transporters because they express pregnane X receptor (PXR). Therefore, as part of a larger study of in vitro to in vivo prediction of inductive drug interactions, we determined induction of various P450s and drug transporters by the anti-human deficiency virus protease inhibitors (PIs) and the prototypic inducer, rifampin, in LS180 cells. Among these proteins, the various PIs significantly induced (n = 3–5) only CYP3A4 and multidrug resistance transporter 1 (MDR1) transcripts (2- to 50-fold). CYP3A4 activity (1′-hydroxymidazolam formation) was increased (2-fold) by rifampin (10 μM) but was reduced by the PIs (1.5- to 7-fold). Surprisingly, constitutive androstane receptor 1 (CAR1) was not found to be expressed in these cells. Additionally, using a reporter assay, we found that PIs did not activate CAR3 (the natural splice variant of CAR1) but significantly activated PXR (2- to 24-fold), which correlated well with induction of CYP3A4 and MDR1 transcripts (∼r = 0.9). Furthermore, in a PXR-knockdown stable LS180 cell line, induction of CYP3A4 and MDR1 mRNA after treatment with PIs and rifampin was significantly reduced (1.4- to 5-fold) compared with that in PXR nonsilenced cells. Based on these data, we conclude that LS180 cells could be used as a readily available, high-throughput cell line to screen for PXR-mediated induction of CYP3A4 and MDR1 transcripts. These data also indicate that the majority of the PIs are likely to produce intestinal drug-drug interactions by inactivating or inhibiting CYP3A enzymes even though they induce CYP3A4 and MDR1 transcripts via PXR. The American Society for Pharmacology and Experimental Therapeutics