| Regulation of Vascular Endothelial Growth Factor Expression by Estrogens and Progestins Salman M. Hyder,1 Jaou-Chen Huang,2 Zafar Nawaz,3 Holly Boettger-Tong,4 Sari Mäkelä,5 Connie Chiappetta,1 and George M. Stancel1 1Department of Integrative Biology and Pharmacology, 2Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Texas-Houston Medical School, Houston, Texas, USA; 3Department of Molecular and Cellular Biology, 4Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas, USA; 5University of Turku, Institute of Biomedicine, Department of Anatomy, Turku, Finland Abstract Estrogens increase the expression of vascular endothelial growth factor (VEGF) mRNA in the rodent uterus. This regulatory effect is rapid, beginning within 1 hr after hormone treatment, dose dependent, and blocked by the pure antiestrogen ICI 182,780. The induction of the transcript is blocked by inhibitors of RNA but not of protein synthesis, and we have recently identified estrogen response elements in the VEGF gene. Collectively, these findings indicate that estrogens regulate uterine VEGF expression at the transcriptional level via the classical nuclear estrogen receptor pathway. Estrogen induction of VEGF occurs in the stromal layer of the rodent uterus, and estradiol induces expression of VEGF transcript levels in cultured human uterine stromal cells. Progestins also induce VEGF expression in the rodent uterus, although the effect is less marked and slower in onset than estrogenic effects. The effect of progestins is blocked by the antiprogestin mifepristone (RU-486) , suggesting that it is also mediated by a classical nuclear receptor pathway. In addition, progestins regulate expression of VEGF mRNA and protein in cultured human T47-D breast cancer cells. The development of uterine leiomyomas is associated with exposure to ovarian sex steroids, abnormal uterine bleeding is commonly seen in patients with leiomyomas, and fibroids require an increased vascular supply for their growth. These observations suggest that VEGF and other angiogenic factors may represent potential targets for the treatment and prevention of uterine fibroids. Key words: breast cancer, endometrium, estradiol, estrogen, fibroids, leiomyomas, progesterone, progestin, uterus, vascular endothelial growth factor, VEGF. -- Environ Health Perspect 108(suppl 5) :785-790 (2000) . http://ehpnet1.niehs.nih.gov/docs/2000/suppl-5/785-790hyder/abstract.html The full version of this article is available for free in HTML format. |