CYP450- and COMT-Derived Estradiol Metabolites Inhibit Activity of Human Coronary Artery SMCs

Abstract—The purpose of this study is to test the hypothesis that the inhibitory effects of estradiol in human coronary vascular smooth muscle cells are mediated via local conversion to methoxyestradiols via specific cytochrome P450s (CYP450s) and catechol-O-methyltransferase (COMT). The inhibitory effects of estradiol on serum-induced cell activity (DNA synthesis, cell number, collagen synthesis, and cell migration) were enhanced by 3-methylcholantherene, phenobarbital (broad-spectrum CYP450 inducers), and &bgr;-naphthoflavone (CYP1A1/1A2 inducer) and were blocked by 1-aminobenzotriazole (broad-spectrum CYP450 inhibitor). Ellipticine, &agr;-naphthoflavone (selective CYP1A1 inhibitors), and pyrene (selective CYP1B1 inhibitor), but not ketoconazole (selective CYP3A4 inhibitor) or furafylline (selective CYP1A2 inhibitor), abrogated the inhibitor effects of estradiol on cell activity, a profile consistent with a CYP1A1/CYP1B1-mediated mechanism. The inhibitory effects of estradiol were blocked by the COMT inhibitors OR486 and quercetin. The estrogen receptor antagonist ICI 182,780 blocked the inhibitory effects of estradiol, but only at concentrations that also blocked the metabolism of estradiol to hydroxyestradiols (precursors of methoxyestradiols). Western blot analysis revealed that coronary smooth muscle cells expressed CYP1A1 and CYP1B1. Moreover, these cells metabolized estradiol to hydroxyestradiols and methoxyestradiols, and the conversion of 2-hydroxyestradiol to 2-methoxyestradiol was blocked by OR486 and quercetin. These findings provide evidence that the inhibitory effects of estradiol on coronary smooth muscle cells are largely mediated via CYP1A1- and CYP1B1-derived hydroxyestradiols that are converted to methoxyestradiols by COMT.

[1]  L. Zacharia,et al.  Methoxyestradiols Mediate Estradiol-Induced Antimitogenesis in Human Aortic SMCs , 2002, Hypertension.

[2]  A. Conney,et al.  NADPH-dependent metabolism of estrone by human liver microsomes. , 2002, The Journal of pharmacology and experimental therapeutics.

[3]  L. Zacharia,et al.  Catecholamines Abrogate Antimitogenic Effects of 2-Hydroxyestradiol on Human Aortic Vascular Smooth Muscle Cells , 2001, Arteriosclerosis, thrombosis, and vascular biology.

[4]  E. Jackson,et al.  Invited Review: Cardiovascular protective effects of 17β-estradiol metabolites , 2001 .

[5]  J. Gustafsson,et al.  Effects of Estrogen on the Vascular Injury Response in Estrogen Receptor α,β (Double) Knockout Mice , 2001 .

[6]  E. Jackson,et al.  Estrogen-induced cardiorenal protection: potential cellular, biochemical, and molecular mechanisms. , 2001, American journal of physiology. Renal physiology.

[7]  L. Zacharia,et al.  Increased 2-Methoxyestradiol Production in Human Coronary Versus Aortic Vascular Cells , 2001, Hypertension.

[8]  E. Jackson,et al.  Cardiovascular protective effects of 17beta-estradiol metabolites. , 2001, Journal of applied physiology.

[9]  L. Zacharia,et al.  Methoxyestradiols mediate the antimitogenic effects of estradiol on vascular smooth muscle cells via estrogen receptor-independent mechanisms. , 2000, Biochemical and biophysical research communications.

[10]  L. Zacharia,et al.  Clinically used estrogens differentially inhibit human aortic smooth muscle cell growth and mitogen-activated protein kinase activity. , 2000, Arteriosclerosis, thrombosis, and vascular biology.

[11]  J. Gustafsson,et al.  Estrogen inhibits the vascular injury response in estrogen receptor beta-deficient female mice. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[12]  P. Männistö,et al.  Catechol-O-methyltransferase (COMT): biochemistry, molecular biology, pharmacology, and clinical efficacy of the new selective COMT inhibitors. , 1999, Pharmacological reviews.

[13]  H. Yamazaki,et al.  Selectivity of polycyclic inhibitors for human cytochrome P450s 1A1, 1A2, and 1B1. , 1998, Chemical research in toxicology.

[14]  A. Conney,et al.  Functional role of estrogen metabolism in target cells: review and perspectives. , 1998, Carcinogenesis.

[15]  R. Karas,et al.  Estrogen inhibits the vascular injury response in estrogen receptor α-deficient mice , 1997, Nature Medicine.

[16]  J. Dwyer,et al.  Estrogen metabolism and excretion in Oriental and Caucasian women. , 1994, Journal of the National Cancer Institute.

[17]  C. Martucci,et al.  P450 enzymes of estrogen metabolism. , 1993, Pharmacology & therapeutics.

[18]  P. Ball,et al.  Formation, metabolism, and physiologic importance of catecholestrogens. , 1990, American journal of obstetrics and gynecology.