AhR interacts with the aryl hydrocarbon nuclear translocator and induces the upregulation of CYP1A1 expression (3). The upregulated CYP1A1 converts BaP into a metabolite that can form DNA

Cytochrome P450 1A1 (CYP1A1) is a member of the cytochrome p450 enzyme family, which is involved in the metabolisms of carcinogenic metabolites, such as benzo(a) pyrene. In this study, we identified miR-892a as a negative regulator of CYP1A1 expression. Luciferase assays revealed a sequence in the 3'-untranslated region of CYP1A1 that displayed a perfect match with miR-892a, and revealed that this sequence was a specific miR-892a target site. The overexpression of miR-892a inhibited the expression of the CYP1A1 protein, and the miR-892a antagonist increased CYP1A1 expression. Of note, benzo(a)pyrene, a major inducer of CYP1A1 transcription, decreased the expression of miR-892a. Moreover, the miR-892a-induced CYP1A1 repression inhibited the benzo(a) pyrene-mediated decrease in cell viability. These data provide insight into the CYP1A1 regulatory network.