Abstract
Cytochrome P450 1B1 (CYP1B1) is a major E2 hydroxylase involved in the metabolism of potential carcinogens. CYP1B1 expression has been reported to be higher in tumors compared to normal tissues, especially in hormone-related cancers including breast, ovary, and prostate tumors. To explore the role of CYP1B1 in cancer progression, we investigated the action of CYP1B1 in cells with increased CYP1B1 via the inducer 7,12-dimethylbenz[α]anthracene (DMBA) or an overexpression vector, in addition to decreased CYP1B1 via the inhibitor tetramethoxystilbene (TMS) or siRNA knockdown. We observed that CYP1B1 promoted cell proliferation, migration, and invasion in MCF-7 and MCF-10A cells. To understand its molecular mechanism, we measured key oncogenic proteins including β-catenin, c-Myc, ZEB2, and matrix metalloproteinases following CYP1B1 modulation. CYP1B1 induced epithelial-mesenchymal transition (EMT) and activated Wnt/β-catenin signaling via upregulation of CTNNB1, ZEB2, SNAI1, and TWIST1. Sp1, a transcription factor involved in cell growth and metastasis, was positively regulated by CYP1B1, and suppression of Sp1 expression by siRNA or DNA binding activity using mithramycin A blocked oncogenic transformation by CYP1B1. Therefore, we suggest that Sp1 acts as a key mediator for CYP1B1 action. Treatment with 4-hydroxyestradiol (4-OHE2), a major metabolite generated by CYP1B1, showed similar effects as CYP1B1 overexpression, indicating that CYP1B1 activity mediated various oncogenic events in cells. In conclusion, our data suggests that CYP1B1 promotes cell proliferation and metastasis by inducing EMT and Wnt/β-catenin signaling via Sp1 induction.
Highlights
Cytochrome P450 1B1 (CYP1B1) belongs to the CYP1 family and shares enzymatic activities with two other CYP1 family members, CYP1A1 and CYP1A2 [1]
Rabbit polyclonal antibodies for CYP1B1, Specificity protein 1 (Sp1), β-catenin, E-cadherin, cyclin D1, vimentin, SNAI1, and Glyceraldehyde 3phosphate dehydrogenase (GAPDH); mouse monoclonal antibody for ZEB2 and c-Myc; Texas Red-conjugated goat antirabbit IgG; and UltraCruzTM Mounting Medium were purchased from Santa Cruz Biotechnology (Santa Cruz, CA, USA)
To the best of our knowledge, the current study represents the first evidence that CYP1B1 enhances epithelial-mesenchymal transition (EMT) and activates Wnt/β-catenin signaling by upregulating Sp1
Summary
Cytochrome P450 1B1 (CYP1B1) belongs to the CYP1 family and shares enzymatic activities with two other CYP1 family members, CYP1A1 and CYP1A2 [1]. CYP1B1 polymorphisms have been implicated as risk factors in various cancers, and CYP1B1-mediated carcinogenesis may depend on CYP1B1 enzymatic activity [17,18,19]. Taken together, these findings suggest that CYP1B1 might be a driver in cancer progression and, represent a significant cancer biomarker and potential target for anticancer therapy. We explored the role of CYP1B1 in carcinogenesis and cancer progression including the molecular mechanism that drives CYP1B1-mediated oncogenesis. We further investigated the key factors driving cell proliferation and invasion following CYP1B1 modulation and found several target proteins that are related to EMT and Wnt/β-catenin signaling. To the best of our knowledge, these findings establish the molecular mechanisms driving CYP1B1-mediated oncogenesis for the first time
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