BHPI is an antagonist of estrogen receptor α (ERα) that blocks 17β-estradiol-induced proliferation of drug-resistant breast, endometrial, and ovarian cancer cell lines at concentrations ranging from 10 to 1,000 nM.1 It is effective in vivo, driving tumor regression in mice bearing MCF-7 xenografts at a dose of 15 mg/kg daily.1 BHPI specifically inhibits ERα-dependent gene expression and protein synthesis by activating the unfolded protein response in cells.1
1.Andruska, N.D., Zheng, X., Yang, X., et al.Estrogen receptor α inhibitor activates the unfolded protein response, blocks protein synthesis, and induces tumor regressionProc. Natl. Acad. Sci. USA112(15)4737-4742(2015)