Benzo[a]pyrene (BaP) activates the aryl hydrocarbon (AHR) and induces the expression of genes involved in xenobiotic metabolism, including CYP1A1. CYP1A1 is involved not only in BaP detoxification but also in metabolic activation, which results in DNA adduct formation. Vitamin D receptor (VDR) belongs to the NR1I subfamily of the nuclear receptor superfamily, which also regulates expression of ...

There is a traditional belief in the Middle East that camel milk may aid in prevention and treatment of numerous cases of cancer yet, the exact mechanism was not investigated. Therefore, we examined the ability of camel milk to modulate the expression of a well-known cancer-activating gene, Cytochrome P450 1a1 (Cyp1a1), and cancer-protective genes, NAD(P)H:quinone oxidoreductase 1 (Nqo1) and gl...

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD; dioxin) is a toxic environmental contaminant that works through dioxin response elements (DRE) to activate gene expression. We tested the hypothesis that cancer-related epigenetic changes suppress dioxin activation of the cytochrome P4501A1 (CYP1A1) gene. 5-Aza-2'-deoxycytidine (5-aza-CdR), an inhibitor of DNA methylation, increases TCDD-inducible CYP1...

Indirubin is a natural arylhydrocarbon receptor (AhR) ligand isolated from human urine. We previously reported that it was more potent than the prototypical ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in a yeast assay system. Here we compared gene expression changes in HepG2 cells exposed to 10 nM of indirubin or TCDD using nylon-membrane-based cDNA arrays with 1176 genes to elucidate th...

Expression of Cyp1a1 and its related enzyme activity have long been used as a biomarker for aryl hydrocarbon receptor (AhR) activation and a warning of dioxin-like toxicity. As a result, induction of Cyp1a1 by pharmaceutical drug candidates or environmental contaminants raises significant concern in risk assessment. The current study evaluates the specificity of Cyp1a1 induction as a marker for...

The present study examined modifications of β-naphthoflavone (β-NF)-induced cytochrome P450 1A1 (CYP1A1) expression by flavonoids in mouse hepatocytes in primary culture. Some flavonoids (apigenin, chrysin, flavone, flavanone, galangin, luteolin, and naringenin) by themselves induced CYP1A1 mRNA expression, especially flavone which was even more effective than β-NF. The effect on β-NF-induced C...

Arsenic is a toxic metalloid known to interact with drug-metabolizing enzymes. In the present study, we investigated the effects of arsenic trioxide (As2O3), recently used as an anticancer drug, on the expression of human cytochrome P450 (P450) 1A1, which bioactivates polycyclic aromatic hydrocarbons into mutagenic metabolites. Clinically relevant concentrations (0.25-5 microM) of As2O3 were de...

The aryl hydrocarbon receptor repressor (AhRR) is a member of the aryl hydrocarbon receptor (AhR) signaling cascade, which mediates dioxin toxicity and is involved in regulation of cell growth and differentiation. The AhRR was described as a feedback modulator, which counteracts AhR-dependent gene expression. We investigated the molecular mechanisms of transcriptional regulation of the human Ah...

background: endometriosis is one of the most commonly encountered benign problems in gynaecology. it is frequently associated with chronic pelvic pain, dysmenorrhoea, menorrhagia and dyspareunia, which lead to infertility. we determined the possible association between cyp1a1 mspi and gstm1 null polymorphism in the pathogenesis of endometriosis. materials and methods: ninety seven cases of endo...

The cytochrome P4501A1 (CYP1A1) enzyme is regulated at the transcriptional level and its expression is influenced by genetic factors, polymorphisms in the structural and regulatory genes, and by environmental factors such as exposure to polycyclic aromatic hydrocarbons (PAHs). To investigate the role of CYP1A1 in breast cancer, we studied CYP1A1 expression in breast tissue, thereby taking all p...