Aryl hydrocarbon receptor-dependent cell cycle arrest in isolated mouse oval cells

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor, which mediates toxic responses to environmental pollutants, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. Besides its well known role in induction of xenobiotic metabolizing enzymes, for instance CYP1A1, the AhR is also involved in tumor promotion in rodents although the underlying mechanisms are still poorly understood. Additionally, the AhR is known to regulate cellular proliferation, which might result in either inhibition or stimulation of proliferation depending on the cell-type studied. Potential targets in hepatocarcinogenesis are liver oval (stem/progenitor) cells. In the pres…