Inefficient UGT-conjugation of adrenal 11β-hydroxyandrostenedione metabolites highlights C11-oxy C steroids as the predominant androgens in prostate cancer.

Although the adrenal C steroids, androstenedione and testosterone, contribute to prostate cancer (PCa) progression the full complement of adrenal androgens, including the C11-oxy C steroids, 11β-hydroxyandrostenedione (11OHA4) and 11β-hydroxytestosterone (11OHT) and their androgenic metabolites, 11keto-testosterone (11KT) and 11keto-dihydrotestosterone (11KDHT) have, to date, not been considered. This study investigated the contribution of 11OHA4 and 11OHT to the pool of active androgens in the prostate. Steroid profiles were determined in LNCaP, C4-2B and VCaP cell models, in PCa tissue, and in plasma focussing on the inactivation, reactivation and glucuronidation of 11OHA4, 11OHT and their downstream products using ultra-performance convergence chromatography tandem mass spectrometry (UPC-MS/MS). The C11-oxy C steroids were the predominant steroids with the production of 11KT and 11KDHT in prostate cell models identifying 11β-hydroxysteroid dehydrogenase type 2 activity. Active:inactive steroid ratios indicated efficient inactivation of dihydrotestosterone (DHT) and 11KDHT by 3α-hydroxysteroid dehydrogenases, while the reactivation of DHT by retinol-like dehydrogenases was greater than the reactivation of 11KDHT. In PCa tissue, inactive C11-oxy C steroids ranged from 27 to 30 ng/g, whereas inactive C steroids were below 1 ng/g. Steroid glucuronidation was impeded: in VCaP cells, the C11-oxy C steroids were unconjugated and the C steroids fully conjugated; in C4-2B cells, all steroids were unconjugated, except for DHT of which 50% was conjugated; in LNCaP cells only androsterone, 11KT and 11β-hydroxyandrosterone were unconjugated. In PCa patients' plasma 11KDHT was present only in the unconjugated form, with 11KT also predominantly unconjugated (90-95%). Even though plasma and tissue sample numbers were limited, this study serves to demonstrate the abundance of C11-oxy C steroids, with notable differences in their metabolism, dictated by steroidogenic enzymes and hampered conjugation, affecting active androgen levels. Larger cohorts are required to analyse profiles in modulated metabolic pathways, in order to shed light on treatment outcomes. The C11-oxy C steroids are involved in PCa, with impeded glucuronidation in PCa ascribing a dominant role to these steroids in disease progression.