Steroid sulfatase/17β-HSD1-IN-4 (compound 37) is a potent dual inhibitor of steroid sulfatase (STS) and 17β-hydroxysteroid dehydrogenase type 1 (17β HSD1). Steroid sulfatase/17β-HSD1-IN-4 irreversibly inhibits hSTS activity (IC50= 63 nM) and has research value in endometriosis and other estrogen-dependent diseases.

Steroid sulfatase/17β-HSD1-IN-4 (compound 37) demonstrates potent inhibition of human steroid sulfatase (hSTS) activity with an IC50 of 63 nM and irreversible inhibition with an IC50 of 60 nM in T47D human breast cancer cells over 24 hours at concentrations up to 1100 nM [1]. Furthermore, at 20 μM for 48 hours, compound 37 reduces HEK-293 cell growth by 15.1% while showing low cytotoxicity [1].