Premium
Effect of CYP17A1 17,20 Lyase Inhibitors on Regulation of Adrenal Androgen Biosynthesis
Author(s) -
Pandey Amit V,
Udhane Sameer S
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.934.2
Subject(s) - cyp17a1 , steroid biosynthesis , pregnenolone , endocrinology , medicine , adrenarche , androgen , adrenocortical carcinoma , chemistry , adrenal cortex , lyase , dehydroepiandrosterone , steroid , pharmacology , biochemistry , enzyme , hormone
Background The P450c17 (CYP17A1) plays a vital role in regulating adrenal androgen production. CYP17A1 localized in the endoplasmic reticulum can catalyze both 17α‐hydroxylase and 17,20 lyase reactions. Understanding the mechanisms regulating 17,20 lyase activity is important for the understanding of hyperandrogenic disorders such as premature, exaggerated adrenarche and the polycystic ovary syndrome, and also for the design of selective 17,20 lyase inhibitors for use in hyperandrogenic states and in sex‐steroid dependent cancers. The orteronel and galeterone are known to inhibit 17,20 lyase activity; however, the precise mechanism of the CYP17A1 inhibition remains unknown. These inhibitors have been developed to treat the castration resistant prostate cancer (CRPC) but little is known about their effect on adrenal androgen biosynthesis. We have studied the specific 17,20 layse inhibitors to understand their effects on CYP17A1 and adrenal androgen biosynthesis. Methods We used NCI‐H295R adenocarcinoma cells to study the effect of orteronel and galeterone. We treated the H295R cells with 0–2μM orteronel and galeterone for 24 hours. Steroid production was labeled with [3H] pregnenolone for 90 min. Steroids were extracted and resolved by thin layer chromatography. For specific analysis of the CYP17A1, CYP19A1 and CYP21A2 activities, cells were treated with 1μM trilostane (a specific blocker of HSD3B) for 90 min before adding radiolabelled steroids. To study the effect of these inhibitors on steroidogenic gene expression we performed the relative quantification PCR (qRT‐PCR). Steroid metabolome of cells was determined in parallel experiments using GC‐MC/LC‐MS. Results The drugs orteronel and galeterone were able to inhibit CYP17A1 activity in H295R cells. Both drugs have more potency towards the 17,20 lyase activity but we also observed that they partially affected 17 alpha‐hydroxylase activity. From our results, we observed the orteronel seems to be more potent and selective towards 17,20 lyase activity than galeterone. However, we also found dihydroepiandrosterone (DHEA), cortisol and androstenedione were drastically decreased by both compounds at 1 and 2μm concentration. Further, we also studied effect of these inhibitors on genes which are involved in androgen biosynthesis. We found slight increase in the HSD3B2 gene expression under galeterone treatment but no change was observed in CYP17A1 and AKR1C3 expression. Conclusions Based on our results we conclude that orteronel is a more potent inhibitor of 17,20 lyase activity and also has partial effect on 17α‐hydroxylase activities. Support or Funding Information This work was supported by grants to Amit V Pandey from the Swiss National Science Foundation and Bern University Research Foundation.