Estradiol (10 nM) rapidly activates sphingosine kinase isoenzyme SphK1 as determined by enhanced phosphorylation on Ser225 in MCF-7 cells. Estradiol (20 nM) stimulates rapid release of sphingosine 1-phosphate (S1P) and dihydro-S1P from MCF-7 cells. SphK1 and estrogen receptor α are mainly responsible for formation of S1P and dihydro-S1P. Down-regulation of ABCC1 or ABCG2 with siRNAs or pharmacological inhibitors decreases Estradiol (10 nM)-mediated release of S1P or dihydro-S1P from MCF-7 cells. [1] Estradiol (10 nM) inhibits miR-21 expression in MCF-7 human breast cancer cells mediated by estrogen receptor α. Estradiol (10 nM) activates several miR-21 target gene reporters activity in MCF-7 cells through inhibiting miR-21 expression. Estradiol (10 nM) increases endogenous miR-21 target genes expression in protein but not RNA levels in MCF-7 cells. [2]

Estradiol (80 μg/kg/day, s.c.) significantly decreases the absolute numbers of total peritoneal cell and macrophages, characterized by a double F4/80- and CD11b-positive staining, in ovariectomized C57BL/6J mice. Estradiol (80 μg/kg/day, s.c.) enhances the LPS-induced expression of proinflammatory cytokines by TGC-elicited macrophages through inhibition of PI3K activity in ovariectomized C57BL/6J mice. Proinflammatory effect of Estradiol is abolished by downregulate estrogen receptor α activity in thioglycolate-elicited macrophages. [3]