Cytochrome P450 (CYP) is a heme protein that plays a crucial role in the metabolism of drugs and other foreign compounds. Specifically, CYP is a key enzyme involved in drug and steroid hydroxylation reactions. Meanwhile, CYP enzymes are associated with various reactions, including O-dealkylation, S-oxidation, epoxidation, and hydroxylation. The multiple effects exhibited by most CYP enzymes may be similar to pro-inflammatory cytokines and IFN. Nonetheless, CYP17 is a microsomal enzyme that catalyzes two different activities, namely 17alpha-hydroxylase and 17,20-lyase. CYP17 is crucial for the biosynthesis of adrenal and gonadal steroids. Moreover, CYP17 is a potent oxidant found in the liver and non steroidogenic tissues, with catalytic properties different from its role in steroid metabolism. Besides, CYP17 inhibitors may affect the synthesis of adrenal glands and de novo castration resistant androgens. Let’s study a CYP17 inhibitor for prostate cancer research, Galeterone.

Galeterone is a CYP17 Inhibitor for Prostate Cancer Research.

At first, Galeterone (TOK-001) is a multifunctional antiandrogen and CYP17 inhibitor (IC50=47 nM) in castration resistant prostate cancer (CRPC). Galeterone is both a CYP17A1 inhibitor and androgen receptor antagonist.

Secondly, the steady-state levels of AR protein are markedly decreased (up to 84%, 15 μM Galeterone) for LNCaP cells cultured in medium supplemented with charcoal-stripped serum. When LNCaP cells are treated with 20 μM Galeterone for 24 h, AR mRNA levels are reduced by 38%.

Thirdly, Galeterone significantly reduces the growth rate of tumor growth compared to control in mice inoculated with LAPC-4 tumors. Upon excision, final tumor weights are also significantly reduced in animals treated with Galeterone compared to animals treated with control, and castration.

Finally, Galeterone is a CYP17 inhibitor for prostate cancer research.


Bruno RD, et al. Steroids. 2011 Nov;76(12):1268-79.  

Soifer HS, et al. Epub 2011 Dec 15.