Regulation of growth-regulated oncogene alpha expression by estrogen in human endothelial cells

AIM: To study the effect of estrogen on expression of growth-regulated onco gene alpha (GRO alpha) in human umbilical vein endothelial cells (HUVEC) in vitro. METHODS: Expressions of CXC chemokine GRO alpha mRNA and protein we re measured by Northern blotting assay and ELISA, respectively. The physiol ogical significance of GRO alpha expression was tested by static cell adhes ion assay. RESULTS: Both the GRO alpha mRNA and protein levels decreased ma rkedly after HUVEC were exposured to 17 beta -estradiol (E-2) 0.05 mu mol/L . Moreover, the inhibition of the protein was depended on the concentration of 17 beta -estradiol. Tamoxifen (0.1 mu mol/L), an estrogen receptor a an tagonist, alone did not affect GRO alpha protein expression, but can revers e the E-2-induced inhibition of GRO alpha protein expression ( by up to 50 %) and the binding of U937 cells to E-2-treated HUVEC (by up to 40 %). CONC LUSION: Estrogen might functionally down-regulates GRO alpha expression thr ough estrogen receptor a on endothelial cells.