Estrogen receptor-alpha agonists promote angiogenesis in human myometrial microvascular endothelial cells.
OBJECTIVE
The relative role of the two estrogen receptors, ERalpha and ERbeta, in mediating angiogenic responses in adult human endothelium is unknown. The aim of this study was to determine whether novel ERalpha-selective agonists, propyl pyrazole triol (PPT) and the tetrahydrochrysene (R,R-THC), up-regulate the expression of vascular endothelial growth factor receptor-2 (VEGFR-2), and promote VEGF-stimulated endothelial cell proliferation in primary cultures of adult female microvascular endothelial cells co-expressing endogenous ERalpha and ERbeta.


METHODS
Confluent primary cultures of microvascular endothelial cells isolated from human myometrium were incubated with 17beta-estradiol (1 and 10 nM), PPT (10 nM to 3 microM), or R,R-THC (10 nM to 3 microM) for 18 hours and VEGFR-2 expression measured by biotin-VEGF165 binding and flow cytometry. Endothelial cell proliferation was assessed in microvascular endothelial cells after incubation with 17beta-estradiol (10 nM), PPT (100 nM), and R,R-THC (100 nM) for 6 days using a tetrazolium-based bioassay.


RESULTS
Both PPT and R,R-THC increased VEGFR-2 expression on myometrial microvascular endothelial cells in a dose-dependent manner, reaching a maximum at 1 microM. Approximately 40% of myometrial microvascular endothelial cell isolates only express ERbeta and do not express ERalpha, and in these neither PPT, R,R-THC, nor 17beta-estradiol increased VEGF binding. PPT- or R,R-THC-stimulated increase in VEGF binding was significantly different between ERalpha+ and ERalpha- microvascular endothelial cell samples (P < .001 and P < .05, respectively). PPT, R,R-THC, and 17beta-estradiol significantly augmented VEGF-stimulated microvascular endothelial cell proliferation in ERalpha+ (P < .05), but not in ERalpha- samples.


CONCLUSIONS
This angiogenic effect of 17beta-estradiol on adult female microvascular endothelial cells is mediated by ERalpha, rather than ERbeta.
Zaitseva
Marina
M
Centre for Women's Health Research, Monash University Department of Obstetrics and Gynaecology, Monash Medical Centre, Clayton, Victoria, Australia.
Yue
Doris Sam
DS
Katzenellenbogen
John A
JA
Rogers
Peter A W
PA
Gargett
Caroline E
CE
D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002911:Chrysenes / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects* / Q000502:physiology; D004730:Endothelium, Vascular / Q000166:cytology; D004958:Estradiol / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000819:agonists* / Q000502:physiology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008833:Microcirculation / Q000166:cytology*; D009215:Myometrium / Q000098:blood supply*; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D010636:Phenols; D011720:Pyrazoles / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism / Q000494:pharmacology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000032:analysis / Q000378:metabolism
D002911:Chrysenes; D047628:Estrogen Receptor alpha; D010636:Phenols; D011720:Pyrazoles; D042461:Vascular Endothelial Growth Factor A; C486184:4,4',4''-(4-propyl-((1)H)-pyrazole-1,3,5-triyl) tris-phenol; D004958:Estradiol; D040301:Vascular Endothelial Growth Factor Receptor-2