Properties of estrogen and hydroxysteroid sulphotransferases in human mammary cancer

Enzymatic regulation of estradiol-17β concentrations in human breast cancer cells

“…wt. of-70,000 [10], which is very similar to that of the bovine enzyme. The latter has been cloned, the protein sequence deduced from the c-DNA corresponding to a mol.…”

“…Whilst estrogen sulfotransferase is specific for the classical phenolic estrogens (E2, E~, and estfiol), hydroxysteroid sulfotransferase has no action on phenolic estrogens, but instead sulfurylates neutral steroids such as dehydroepiandrosterone (DHEA), and the related adrenal-derived estrogen 5-androstene-313, 17[~-diol. Both of the enzymes in human mammary cancer cells show extremely high affinities for their respective steroid substrates (low nM range) [7,10] and cooperativity in their binding [10]. Estrogen sulfotransferase, partially purified from such cells, has a mol.…”

Oestrogen sulphotransferases in malignant and normal human breast tissue

“…The second is that these STs are similar, if not identical, to the STs isolated from other human tissues. The unusual molecular masses reported by Adams &Phillips (1990) andRozhin et al (1986) may be explained by the fact that relatively mild conditions were used for isolation, so the enzymes may well have remained in their oligomeric forms. More recent studies using specific anti-ST antibodies have identified STs of the expected molecular masses, and the situation is likely to be clarified further now that reagents are available to detect and characterise ST mRNA expression.…”

Recent insight on the control of enzymes involved in estrogen formation and transformation in human breast cancer

“…MCF-7, ZR-75-1, T-47D) and is efficient in catalyzing the sulfation of 2-hydroxy-estrone and 2-hydroxy-estradiol, and the hEST-2, which selectively catalyzes sulfonation of estradiol, estrone, and ethinyl estradiol [33,116,117]. Sulfotransferases in normal and carcinomous breast is extensively demonstrated [118][119][120].…”