Oxysterol regulation of estrogen receptor α-mediated gene expression in a transcriptional activation assay system using HeLa cells

In order to test the estrogenic activity of sterol oxidation products from cholesterol and phytosterols, an estrogen-dependent gene expression assay was performed in estrogen receptor α-stably transformed HeLa cells. The ranking of the estrogenic potency of these compounds was different: 17β-estradiol ≫ genistein ≫ β-epoxycholesterol = daidzein = cholestanetriol = 22(R)-hydroxycholesterol = 20(S)-hydroxycholesterol = sitostanetriol > campestanetriol = β-epoxysitosterol = 7β-hydroxycholesterol. These compounds were not estrogenic in estrogen receptor-negative HeLa cells.