Contribution of α2-adrenoceptors to the mitogenic effect of catecholestrogen in human breast cancer MCF-7 cells

摘要: Abstract Catecholestrogens are estrogen metabolites formed by hydroxylation of 17β-estradiol and estrone at either the C-2 or C-4 position, rivaling parent estrogens in concentration. The objective present work was to assess if their catechol group could make them induce proliferation human breast cancer cells via α 2 -adrenoceptors. In competition studies MCF-7 cells, high concentrations 2-hydroxy-estradiol (2-OH-E ), 2-hydroxy-estrone 1 ) 4-hydroxy-estrone (4-OH-E competed for [ 3 H]-rauwolscine binding, whereas 4-hydroxy-estradiol did not. contribution -adrenoceptors receptors (ERs) enhancement analyzed with specific antagonists. -adrenergic antagonist yohimbine partially reversed effect catecholestrogens except 4-OH-E . selective ER downregulator ICI-182780 fulvestrant totally all hydroxylated catecholestrogens. When analyzing combination both antagonists MCF-7, ERs 2-OH-E , mixed, only receptor implied an ER. MDA-MB-231 (ER-α negative) stimulation these three reversal adrenergic also observed. It can be concluded that contribute least part mitogenic