Canonical and Noncanonical Androgen Metabolism and Activity

Circulating adrenal 11-oxygenated androgens are associated with clinical outcome in endometrial cancer

Context

Recent evidence support that androgens play an important role in the etiology of endometrial cancer (EC). Adrenal-derived 11-oxygenated androgens are highly potent agonists of the androgen receptor (AR), comparable to testosterone (T) and dihydrotestosterone (DHT) that have not been studied in the context of EC.

Methodology

We studied a cohort of 272 newly diagnosed postmenopausal EC cases undergoing surgical treatment. Circulating concentrations of seven 11-oxygenated androgens including precursors, potent androgens and their metabolites were established in serum samples collected before and 1 month after surgery using a validated liquid chromatography tandem mass spectrometry method (LC-MS/MS). Free (unconjugated) and total (free + sulfate and glucuronide conjugates following enzymatic hydrolysis) were analyzed in relation to clinicopathological features, recurrence and disease-free survival (DFS).

Results

Levels of 11-oxygenated androgens were weakly correlated to those of canonical androgens such as testosterone (T) and dihydrotestosterone (DHT), with no evidence of their association with clinicopathological features. Levels of 11-oxygenated androgens declined after surgery but remained higher in overweight and obese compared to normal weight cases. Higher levels of preoperative free 11-ketoandrosterone (11KAST) were associated with an increased risk of recurrence (Hazard ratio (HR) of 2.99 (95%CI=1.09-8.18); P=0.03). Postoperative free 11β-hydroxyandrosterone (11OHAST) levels were adversely associated with recurrence and DFS (HR = 3.23 (1.11-9.40); P=0.03 and 3.27 (1.34-8.00); P=0.009, respectively).

Conclusion

11-oxygenated androgen metabolites emerge as potential prognostic markers of EC.

Basics of androgen synthesis and action

Androgens are essential sex steroid hormones for both sexes. Testosterone (T) is the predominant androgen in males, while in adult females, T concentrations are about 15-fold lower and androgen precursors are converted to estrogens. T is produced primarily in testicular Leydig cells in men, while in women precursors are biosynthesised in the adrenal cortex and ovaries and converted into T in the periphery. The biosynthesis of T occurs via a series of enzymatic reactions in steroidogenic organs. Notably, the more potent androgen, dihydrotestosterone, may be synthesized from T in the classic pathway, however, alternate metabolic pathways also exist. The classic action of androgens on target organs is mediated through the androgen receptor, which regulates nuclear receptor gene transcription. However, the androgen-androgen receptor complex may also interact directly with membrane proteins or signaling molecules to exert more rapid effects. This review summarizes the current knowledge of androgen biosynthesis, mechanisms of action and endocrine effects in human biology, and relates these effects to respective human congenital and acquired disorders.

Statins and prostate cancer-hype or hope? The epidemiological perspective

BACKGROUND

Men using cholesterol-lowering statin medications have been found to have lower risks of both advanced and fatal prostate cancer in multiple registry-based studies and prospective cohort studies. Statin use has also been associated with longer survival among men already diagnosed with prostate cancer. Mechanisms responsible for purported anti-cancer effects of statins are not well understood but may offer insight into prostate cancer biology.

METHODS

We summarise epidemiological data from studies of statins and prostate cancer and discuss to what extent these findings can be interpreted as causal. Additionally, lipid-mediated and non-lipid-mediated mechanisms that may contribute to potential anti-cancer effects of statins are reviewed. Finally, we consider treatment settings and molecular subgroups of men who might benefit more than others from statin use in terms of prostate cancer-specific outcomes.

RESULTS

Data from prospective observational studies generally reported a lower risk of fatal prostate cancer among statin users. There is some evidence for serum cholesterol-lowering as an indirect mechanism linking statins with advanced and fatal prostate cancer. Window-of-opportunity clinical trials show measurable levels of statins in prostate tissue highlighting potential for direct effects, whilst observational data suggest possible statin-driven modulation of prostate microenvironment inflammation. Additionally, emerging data from registry studies support a potential role for statins within the context of androgen deprivation therapy and anti-androgen treatment.

CONCLUSION

Prospective and registry-based studies support a lower risk of advanced and fatal prostate cancer in statin users relative to non-users, as well as better outcomes among prostate cancer patients. The few randomised-controlled trials conducted so far have short follow-up, lack identified molecular subgroups, and do not provide additional support for the observational results. Consequently, additional evidence is required to determine which men may experience greatest benefit in terms of prostate cancer-specific outcomes and how statin effects may vary according to molecular tumour characteristics.

11-Oxygenated Androgens Useful in the Setting of Discrepant Conventional Biomarkers in 21-Hydroxylase Deficiency

Context

Serum 17-hydroxyprogesterone (17OHP) and androstenedione (A4) are the conventional biomarkers used to assess disease control in patients with 21-hydroxylase deficiency (21OHD). However, discrepancy between the two is not uncommon, limiting interpretation.

Objective

To evaluate 11-oxyandrogens in discriminating good versus poor disease control in 21OHD in the setting of discrepant 17OHP and A4.

Methods

Retrospective analysis of 2738 laboratory assessments obtained as part of Natural History Study of congenital adrenal hyperplasia (CAH) at the National Institutes Health Clinical Center. Patients with discrepant 17OHP and A4 and available sera were selected. A 15-steroid mass-spectrometry panel was performed in sera from patients with 21OHD and age- and sex-matched controls. Patients were categorized in "good" or "poor" control based on clinical assessment (bone age advancement, signs and symptoms of precocious puberty, menstrual irregularity, hirsutism, or hypogonadotrophic hypogonadism).

Results

Discrepant 17OHP and A4 was found in 469 (17%) laboratory assessments. Of these, 403 (86%) had elevated 17OHP with A4 in reference range. Of 46 patients with available sera, 30 (65%) were in good control. Median fold elevation relative to controls was higher in patients with poor versus good control for 11-hydroxytestosterone (median [interquartile range], 2.82 [1.25-5.43] vs 0.91 [0.49- 2.07], P = .003), and 11-ketotestosterone (3.57 [2.11-7.41] vs 1.76 [1.24-4.00], P = .047). Fold elevation of 11-hydroxytestosterone between 3.48 (sensitivity 97%, specificity 47%) and 3.88 (sensitivity 100%, specificity 40%) provided the best discrimination between poor vs good control.

Conclusion

11-Oxyandrogens, especially 11-hydroxytestosterone, may be useful in the management of CAH when conventional biomarkers are inconclusive.

Dihydrotestosterone Induces Proliferation, Migration, and Invasion of Human Glioblastoma Cell Lines

Introduction

Glioblastomas (GBM) are the most frequent and aggressive human brain tumors due to their high capacity to migrate, invade healthy brain tissue, and resist anticancer therapies. It has been reported that testosterone (T) levels are higher in patients with GBM than in healthy controls. It has also been dem{}onstrated that T induces proliferation, migration, and invasion of human GBM cell lines. T is mainly metabolized to 5α-dihydrotestosterone (DHT) by the enzyme 5α-reductase (5αR), but the role of this metabolite in GBM cells is unknown.

Methods

The expression of 5αR isoenzymes and AR in biopsies of GBMs was determined by the analysis of TCGA. U87 and U251 GBM cell lines were grown in supplemented DMEM. For evaluating the expression of AR in U251 and U87 cells, a RT-qPCR was performed. The cells were treated with T, DHT, finasteride (FIN), dutasteride (D), and the combined treatments, FIN+T and D+T or vehicle. After treatments, the viability was quantified by the trypan blue exclusion assay, the proliferation was evaluated by BrdU incorporation, and migration and invasion were analyzed by the scratch-wound and the transwell assays, respectively.

Results

In a set of glioma biopsies from TCGA, we observed that SRD5A2 (5αR2) expression was higher in GBM and in low-grade gliomas than in normal brain tissue. We observed that DHT and T increased proliferation, migration, and invasion of human GBM cell lines: U87 and U251. F and D, drugs that inhibit 5αR activity, blocked the effects of T on GBM cells.

Discussion

These data suggest that T induces human GBM progression through its conversion into DHT. These results can be related to the chemical structure of DHT, which increases its affinity for AR and decreases five times the rate of dissociation compared to T. Also, it is possible that DHT mediates the effects of T on cell human GBM cells motility by changing the expression of genes involved in tumor infiltration.