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Effect of Tumor Necrosis Factor- on Estrogen Metabolism and Endometrial Cells: Potential Physiological and Pathological Relevance

Department of Obstetrics and Gynecology (S.A.S., M.W.K., C.R.D.-A., S.K.B., R.K.), University of Texas Medical Branch, Galveston, Texas 77555; Department of Pharmacology and Toxicology (S.A.S.), Faculty of Pharmacy, Al-Azahr University, Cairo, Egypt; Department of Tumor Biology (M.W.K.), National Cancer Institute, Cairo University, Cairo, Egypt; Laboratory of Proteomics and Analytical Technologies (X.X., T.D.V.), Science Applications International Corporation-Frederick, Inc., National Cancer Institute-Frederick, Frederick, Maryland 21702; and Department of Obstetrics and Gynecology (S.S.), University of Wisconsin, Madison Wisconsin 53792

Address all correspondence and requests for reprints to: Salama A. Salama, Ph.D., Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Texas Medical Branch at Galveston, 300 University Boulevard, Galveston, Texas 77555. E-mail: sasalama{at}utmb.edu.

Context: Estrogen and its metabolites play a critical role in the pathophysiology of the endometrium. The bioavailability of estrogen and estrogen metabolites in endometrial tissues depends on the expression of enzymes involved in estrogen biosynthesis and metabolism. Substantial evidence indicates that estrogen-dependent endometrial disorders are also associated with proinflammatory milieu. However, the mechanism whereby inflammation contributes to these conditions is not known.

Objective: The objective of the study was to investigate the effect of TNF- on estrogen metabolism and the expression of estrogen-metabolizing genes in human endometrial glandular epithelial cells (EM1).

Design: EM1 were treated with 17β-estradiol (E2) with or without TNF-. Capillary liquid chromatography-tandem mass spectrometry analysis was used for quantitative measurement of estrogens and estrogen metabolites. Western blot analysis, reporter gene assay, and real-time RT-PCR were used to assess the expression of estrogen-metabolizing genes.

Results: TNF- treatment significantly increased the level of total estrogen and estrogen metabolites and significantly increased the rate of conversion of estrone (E1) into E2. TNF- also enhanced the oxidative metabolism of estrogen into catecholestrogens with concomitant inhibition of their conversion into methoxyestrogens. Gene expression analysis revealed that TNF- induced the expression of genes involved in E2 biosynthesis (steroidogenic factor-1 and aromatase) and activation (17β- hydroxysteroid dehydrogenase type 1 and cytochrome P-450, 1B1) with simultaneous repression of genes involved in estrogen inactivation (17β-hydroxysteroid dehydrogenase type 2; catechol O-methyltransferase; and nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase 1).

Conclusion: TNF- increases the local estrogen biosynthesis in human endometrial glandular cells and directs estrogen metabolism into more hormonally active and carcinogenic metabolites. These effects may impact many physiological and pathological processes that occur within the endometrium.