New frontiers in androgen biosynthesis and metabolism

Advances and challenges in liquid chromatography-spectrometry (LC-MS) methodology for quantifying androgens and estrogens in human serum and plasma

Accurate quantification of androgens and estrogens is critical for elucidating their roles in endocrine disorders and advancing research on their functions in human biology and pathophysiology. This review highlights recent advances and ongoing challenges in liquid chromatography- mass spectrometry (LC- MS) methodology for quantifying androgens and estrogens in human serum and plasma. We summarized current approaches for analyzing the different forms of androgens and estrogens, along with their reported levels in publications from 2010 to the present. These published levels pointed out the inconsistencies in reference intervals across studies. To address these issues, advances in derivatization methods and chromatographic separation techniques are reviewed. Future perspectives for improving the accuracy and consistency of hormone quantification in clinical and research settings were also proposed.

Androgen receptor monomers and dimers regulate opposing biological processes in prostate cancer cells

Most prostate cancers express the androgen receptor (AR), and tumor growth and progression are facilitated by exceptionally low levels of systemic or intratumorally produced androgens. Thus, absolute inhibition of the androgen signaling axis remains the goal of current therapeutic approaches to treat prostate cancer (PCa). Paradoxically, high dose androgens also exhibit considerable efficacy as a treatment modality in patients with late-stage metastatic PCa. Here we show that low levels of androgens, functioning through an AR monomer, facilitate a non-genomic activation of the mTOR signaling pathway to drive proliferation. Conversely, high dose androgens facilitate the formation of AR dimers/oligomers to suppress c-MYC expression, inhibit proliferation and drive a transcriptional program associated with a differentiated phenotype. These findings highlight the inherent liabilities in current approaches used to inhibit AR action in PCa and are instructive as to strategies that can be used to develop new therapeutics for this disease and other androgenopathies.

Inhibition of aldo-keto reductase 1C3 overcomes gemcitabine/cisplatin resistance in bladder cancer

Systemic chemotherapy with gemcitabine and cisplatin (GC) has been used for the treatment of bladder cancer in which androgen receptor (AR) signaling is suggested to play a critical role. However, its efficacy is often limited, and the prognosis of patients who develop resistance is extremely poor. Aldo-keto reductase 1C3 (AKR1C3), which is responsible for the production of a potent androgen, 5α-dihydrotestosterone (DHT), by the reduction of 5α-androstane-3α,17β-dione (5α-Adione), has been attracting attention as a therapeutic target for prostate cancer that shows androgen-dependent growth. By contrast, the role of AKR1C3 in bladder cancer remains unclear. In this study, we examined the effect of an AKR1C3 inhibitor on androgen-dependent proliferation and GC sensitivity in bladder cancer cells. 5α-Adione treatment induced the expression of AR and its downstream factor ETS-domain transcription factor (ELK1) in both T24 cells and newly established GC-resistant T24GC cells, while it did not alter AKR1C3 expression. AKR1C3 inhibitor 2j significantly suppressed 5α-Adione-induced AR and ELK1 upregulation, as did an AR antagonist apalutamide. Moreover, the combination of GC and 2j in T24GC significantly induced apoptotic cell death, suggesting that 2j could enhance GC sensitivity. Immunohistochemical staining in surgical specimens further revealed that strong expression of AKR1C3 was associated with significantly higher risks of tumor progression and cancer-specific mortality in patients with muscle-invasive bladder cancer. These results suggest that AKR1C3 inhibitors as adjunctive agents enhance the efficacy of GC therapy for bladder cancer.

Morphology of the urogenital papilla of the male marine teleost Black Rockfish, Sebastes schlegelii (Hilgendorf, 1880), and its role in internal fertilization

There are few detailed descriptions of the morphology of the male external genitalia, the urogenital papilla (UGP), of the Black Rockfish (Sebastes schlegelii Hilgendorf, 1880). The purpose of this study was to evaluate this organ histologically and to determine the time of development of the UGP in Black Rockfish. Twelve adult males, three adult females and around 500 juveniles were used in the experiment. The juveniles were divided into normal developmental and androgen groups. The androgen group was exposed to methyltestosterone (100 μg/L) for 2 h daily for 38 days. Samples (N = 10 per sampling) were randomly selected for analysis every 5 days from 30 to 116 days after birth. Parameters assessed included the type of epithelium, composition of connective tissue, muscular tissue, and the timing of UGP development. Differences in these parameters between normal developmental and androgen groups were evaluated. The results indicated that the UGP of the adult fish contains the sperm duct and ureter, which have the function of transporting sperm and urine, respectively. The androgen-treated juvenile fish developed the UGP earlier than the normal development group. This study provides a reference for understanding the external genitalia of other viviparous fishes by studying the UGP of the male Black Rockfish.

The A-ring reduction of 11-ketotestosterone is efficiently catalysed by AKR1D1 and SRD5A2 but not SRD5A1

Testosterone and its 5α-reduced form, 5α-dihydrotestosterone, were previously thought to represent the only active androgens in humans. However, recent studies have shown that the potent androgen, 11-ketotestosterone, derived from the adrenal androgen precursor, 11β-hydroxyandrostenedione, may in fact serve as the primary androgen in healthy women. Yet, despite recent renewed interest in these steroids, their downstream metabolism has remained undetermined. We therefore set out to investigate the metabolism of 11-ketotestosterone by characterising the 5α- or 5β-reduction commitment step. We show that inactivation of 11-ketotestosterone is predominantly driven by AKR1D1, which efficiently catalyses the 5β-reduction of 11-ketotestosterone, committing it to a metabolic pathway that terminates in 11-ketoetiocholanolone. We demonstrate that 5α-reduction of 11-ketotestosterone is catalysed by SRD5A2, but not SRD5A1, and terminates in 11-ketoandrosterone, but is only responsible for a minority of 11-ketotestosterone inactivation. However, as 11-ketoetiocholanolone is also generated by the metabolism of the glucocorticoid cortisone, 11-ketoandrosterone should be considered a more specific urinary marker of 11-ketotestosterone production.

Through the Looking-Glass: Reevaluating DHEA Metabolism Through HSD3B1 Genetics

Dehydroepiandrosterone (DHEA) and DHEA sulfate together are abundant adrenal steroids whose physiological effects are mediated through their conversion to potent downstream androgens. 3β-Hydroxysteroid dehydrogenase isotype 1 (3βHSD1) facilitates the rate-limiting step of DHEA metabolism and gates the flux of substrate into the distal portion of the androgen synthesis pathway. Notably, a germline, missense-encoding change, HSD3B1(1245C), results in expression of 3βHSD1 protein that is resistant to degradation, yielding greater potent androgen production in the periphery. In contrast, HSD3B1(1245A) encodes 3βHSD1 protein that is easily degraded, limiting peripheral androgen synthesis. These adrenal-permissive (AP) and adrenal-restrictive (AR) alleles have recently been associated with divergent outcomes in androgen-sensitive disease states, underscoring the need to reevaluate DHEA metabolism using HSD3B1 genetics.

The role of adrenal derived androgens in castration resistant prostate cancer

Castration resistant prostate cancer (CRPC) remains androgen dependant despite castrate levels of circulating testosterone following androgen deprivation therapy, the first line of treatment for advanced metstatic prostate cancer. CRPC is characterized by alterations in the expression levels of steroidgenic enzymes that enable the tumour to derive potent androgens from circulating adrenal androgen precursors. Intratumoral androgen biosynthesis leads to the localized production of both canonical androgens such as 5α-dihydrotestosterone (DHT) as well as less well characterized 11-oxygenated androgens, which until recently have been overlooked in the context of CRPC. In this review we discuss the contribution of both canonical and 11-oxygenated androgen precursors to the intratumoral androgen pool in CRPC. We present evidence that CRPC remains androgen dependent and discuss the alterations in steroidogenic enzyme expression and how these affect the various pathways to intratumoral androgen biosynthesis. Finally we summarize the current treatment strategies for targeting adrenal derived androgen biosynthesis.

Human steroid biosynthesis, metabolism and excretion are differentially reflected by serum and urine steroid metabolomes: A comprehensive review

Advances in technology have allowed for the sensitive, specific, and simultaneous quantitative profiling of steroid precursors, bioactive steroids and inactive metabolites, facilitating comprehensive characterization of the serum and urine steroid metabolomes. The quantification of steroid panels is therefore gaining favor over quantification of single marker metabolites in the clinical and research laboratories. However, although the biochemical pathways for the biosynthesis and metabolism of steroid hormones are now well defined, a gulf still exists between this knowledge and its application to the measured steroid profiles. In this review, we present an overview of steroid hormone biosynthesis and metabolism by the liver and peripheral tissues, specifically highlighting the pathways linking and differentiating the serum and urine steroid metabolomes. A brief overview of the methodology used in steroid profiling is also provided.

Androgen signaling in male fishes: Examples of anti-androgenic chemicals that cause reproductive disorders

Similar to other vertebrates, androgens regulate spermatogenesis in fishes. In teleosts, the main androgen is 11-Ketotestosterone (11-KT), which is oxidized testosterone (T) at the C₁₁ position. Compared to T, 11-KT is a nonaromatizable steroid, and does not convert to 17β-estradiol. However, circulatory levels of both T and 11-KT undergo seasonal variations along with testicular development. Physiological functions of androgens are mediated via androgen receptor (Ar). So far, nuclear Ar and membrane Ar have been identified in fishes. In the present study, we reviewed androgen biosynthesis in fishes, compared molecular structure of nuclear Ar in models of mammals and fishes, and investigated the mechanisms of action of environmental contaminants that differentially disrupt androgen signaling in fish reproduction. In the latter case, the adverse effects of vinclozolin (VZ) and bis(2-ethylhexyl) phthalate (DEHP) are compared. Both VZ and DEHP are capable of decreasing sperm quality in males. Vinclozolin causes an increase in 11-KT production associated with increases in kisspeptin (kiss-1) and salmon gonadotropin-releasing hormone (gnrh3) mRNA levels as well as circulatory levels of luteinizing hormone (Lh). In contrast, DEHP inhibits 11-KT production associated with a decrease in circulatory Lh levels. However, DEHP-inhibited 11-KT production is not associated with changes in kiss-1 and gnrh3 mRNA levels. Studies also show that VZ alters ar mRNA levels, while DEHP is without effect. These suggest that VZ and DEHP act differentially to cause androgen-dependent reproductive disorder in male fishes. Molecular analyses of the nuclear AR show that both DNA and ligand binding domains (DBD and LBD, respectively) are highly conserved within models of mammals and fishes. A phylogeny tree of the AR shows distinct clusters between mammals and fishes. In fishes, subtypes of Arα and Arβ are also separated in distinct clusters. Thus, further studies need to generate ar knockout fish model to better elucidate androgen regulation of reproduction in fishes via Ar.

Functional genomic studies reveal the androgen receptor as a master regulator of cellular energy metabolism in prostate cancer

Sex-steroid hormones have been investigated for decades for their oncogenic properties in hormone-dependent cancers. The increasing body of knowledge on the biological actions of androgens in prostate cancer has led to the development of several targeted therapies that still represent the standard of care for cancer patients to this day. In the prostate, androgens promote cellular differentiation and proper tissue development. These hormones also promote the aberrant proliferation and survival of prostate cancer cells. Over the past few years, sequencing technologies for functional genomic analyses have rapidly expanded, revealing novel functions of sex-steroid hormone receptors other than their classic roles. In this article, we will focus on transcriptomic- and genomic-based evidence that demonstrates the importance of the androgen receptor signaling in the regulation of prostate cancer cell metabolism. This is significant because the reprogramming of cell metabolism is a hallmark of cancer. In fact, it is clear now that the androgen receptor contributes to the reprogramming of specific cellular metabolic pathways that promote tumor growth and disease progression, including aerobic glycolysis, mitochondrial respiration, fatty acid ß-oxidation, and de novo lipid synthesis. Overall, beyond regulating development, differentiation, and proliferation, the androgen receptor is also a master regulator of cellular energy metabolism.

Androgenic signaling systems and their role in behavioral evolution

Sex steroids mediate the organization and activation of masculine reproductive phenotypes in diverse vertebrate taxa. However, the effects of sex steroid action in this context vary tremendously, in that steroid action influences reproductive physiology and behavior in markedly different ways (even among closely related species). This leads to the idea that the mechanisms underlying sex steroid action similarly differ across vertebrates in a manner that supports diversification of important sexual traits. Here, we highlight the Evolutionary Potential Hypothesis as a framework for understanding how androgen-dependent reproductive behavior evolves. This idea posits that the cellular mechanisms underlying androgenic action can independently evolve within a given target tissue to adjust the hormone's functional effects. The result is a seemingly endless number of permutations in androgenic signaling pathways that can be mapped onto the incredible diversity of reproductive phenotypes. One reason this hypothesis is important is because it shifts current thinking about the evolution of steroid-dependent traits away from an emphasis on circulating steroid levels and toward a focus on molecular mechanisms of hormone action. To this end, we also provide new empirical data suggesting that certain cellular modulators of androgen action-namely, the co-factors that dynamically adjust transcritpional effects of steroid action either up or down-are also substrates on which evolution can act. We then close the review with a detailed look at a case study in the golden-collared manakin (Manacus vitellinus). Work in this tropical bird shows how androgenic signaling systems are modified in specific parts of the skeletal muscle system to enhance motor performance necessary to produce acrobatic courtship displays. Altogether, this paper seeks to develop a platform to better understand how steroid action influences the evolution of complex animal behavior.

Intracrine androgen biosynthesis, metabolism and action revisited

Androgens play an important role in metabolic homeostasis and reproductive health in both men and women. Androgen signalling is dependent on androgen receptor activation, mostly by testosterone and 5α-dihydrotestosterone. However, the intracellular or intracrine activation of C19 androgen precursors to active androgens in peripheral target tissues of androgen action is of equal importance. Intracrine androgen synthesis is often not reflected by circulating androgens but rather by androgen metabolites and conjugates. In this review we provide an overview of human C19 steroid biosynthesis including the production of 11-oxygenated androgens, their transport in circulation and uptake into peripheral tissues. We conceptualise the mechanisms of intracrinology and review the intracrine pathways of activation and inactivation in selected human tissues. The contribution of liver and kidney as organs driving androgen inactivation and renal excretion are also highlighted. Finally, the importance of quantifying androgen metabolites and conjugates to assess intracrine androgen production is discussed.

Steroidogenic enzymes, their products and sex steroid receptors during testis development and spermatogenesis in the domestic cat (Felis catus)

In the present study we comprehensively characterize intratesticular sex steroid production, metabolism and receptors in the domestic cat to elucidate the role of testosterone, estradiol and progesterone in testis development, steroid synthesis and spermatogenesis. There is a great demand for new concepts of fertility control in domestic (feral) cats and wild felids. The acquired knowledge will help to understand the regulation of spermatogenesis in felids, and may reveal new target points for male contraception. Progesterone and androgens are produced throughout all stages of testicular development; their synthesizing enzymes are mainly expressed in Leydig cells, and to a much lesser extent also in tubular cells. Aromatase (CYP19A1), the estrogen synthesizing enzyme, is only present in the tubuli and is first detectable in spermatocytes and round spermatids at puberty. As shown by elevated expression of the enzymes steroid 5-α-reductase type 1 (SRD5A) and aldo-keto-reductase family 1 member C3 (AKR1C3), the capacity to metabolize particular steroids increases during testis development. Apparently, this refers to a decreasing intra-testicular testosterone concentration per mg tissue with increasing testis weight during postpuberty. The increasing potential of sulfation of E2 by estrogen sulfotransferase (SULT1E1) with ongoing development might be responsible for the low level of unconjugated intratesticular estradiol in all stages of development probably due to facilitated excretion of conjugated estrogens. For the first time, expression of the progesterone membrane receptor components 1 and 2 (PGRMC1, PGRMC2) was studied in mammalian testis tissue. Both of these and also the progesterone receptor (PGR) are expressed depending on the developmental stage and cell type, suggesting an important regulatory role of progesterone in the testis. Androgen receptor (AR) is present in almost all cell types except for some spermatogenic cells. The co-localization of aromatase with estrogen receptor alpha (ESR1) in spermatocytes and round spermatids of domestic cat testis indicates an auto-/paracrine function of estrogen in spermatogenesis. In summary, the testis of the domestic cat is an important source of sex steroids. All of them could act within the testis but additionally, at least androgens and estrogens are likely secreted by the testis, partly as conjugated steroids.

Di-(2-ethylhexyl) phthalate inhibits testosterone level through disturbed hypothalamic-pituitary-testis axis and ERK-mediated 5α-Reductase 2

Di-(2-ethylhexyl) phthalate (DEHP) has reproductive toxicity and can affect male reproductive development. In order to clarify adverse effects of DEHP on testicular physiology and testosterone production, Sprague-Dawley (SD) rats were dosed daily with DEHP by gavage for 30days; TM3 cells (mouse Leydig cell line) were treated with DEHP for 24h after pretreatment with vitamin C or U0126. Results indicated that the hypothalamic-pituitary-testis (HPT) axis was disturbed and serum testosterone, LH and FSH levels were decreased following DEHP exposure. Histomorphological changes of rat testes were also observed, such as deformed seminiferous tubules, aggregated chromatin, multiple vacuoles, swollen mitochondria, apoptotic germ cells and Sertoli cells, as well as increased Leydig cell numbers. Moreover, DEHP caused oxidative stress in vivo and in vitro and then induced the ERK pathway, which was required to mediate 5α-Reductase 2 and scavenger receptor class B-1 (SRB1) levels. However, levels of steroidogenic acute regulatory protein (StAR), 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β-hydroxysteroid dehydrogenase (17β-HSD), P450 17α-hydroxylase/17.20 lyase (P450c17), and P450 side-chain cleavage enzyme (P450scc) were not significantly altered after DEHP exposure. Taken together, DEHP-disturbed HPT axis and induced 5α-Reductase 2 contribute to the reduction of serum testosterone level. The activated ERK pathway is required to modulate expressions of 5α-Reductase 2 and SRB1.

Inhibition of estrogen biosynthesis enhances lymphoma growth in mice

Most lymphomas show higher incidence and poorer prognosis in males compared to females. However, the endocrine contribution to this gender difference is not entirely known. Here we show that castration accelerates lymphoma growth in C57BL6 male mice grafted with murine EG7 T cell lymphoma cells. However, the androgen receptor antagonist Bicalutamide did not affect lymphoma growth, suggesting no impact of androgen receptor signaling on lymphoma progression. In contrast, inhibition of androgen-to-estrogen conversion by the aromatase inhibitor (AI) Letrozole induced faster lymphoma growth in mice, suggesting that androgens impact lymphoma growth through its conversion to estrogens. This was supported by the inability of dihydrotestosterone, which is not converted to estrogens by aromatase, to influence lymphoma growth in castrated male mice. Lymphoma growth was also stimulated in immunocompromised mice grafted with human B cell lymphoma (Granta-519) and treated with either reversible or irreversible AIs, showing that the blockage of estrogen synthesis caused enhanced growth of both murine T and human B cell lymphomas and with different AIs. Additionally, AI-treated EG7 lymphomas showed accelerated growth not only in male but also in intact female mice. Altogether, our results demonstrate that aromatase inhibition accelerates lymphoma growth but not androgens per se, highlighting a protective role of estrogens in lymphoma pathogenesis. These results also raise concern that the use of AIs in women with breast cancer might enhance lymphoma progression.

A low carbohydrate, high protein diet suppresses intratumoral androgen synthesis and slows castration-resistant prostate tumor growth in mice

Dietary factors continue to preside as dominant influences in prostate cancer prevalence and progression-free survival following primary treatment. We investigated the influence of a low carbohydrate diet, compared to a typical Western diet, on prostate cancer (PCa) tumor growth in vivo. LNCaP xenograft tumor growth was studied in both intact and castrated mice, representing a more advanced castration resistant PCa (CRPC). No differences in LNCaP tumor progression (total tumor volume) with diet was observed for intact mice (P = 0.471) however, castrated mice on the Low Carb diet saw a statistically significant reduction in tumor growth rate compared with Western diet fed mice (P = 0.017). No correlation with serum PSA was observed. Steroid profiles, alongside serum cholesterol and cholesteryl ester levels, were significantly altered by both diet and castration. Specifically, DHT concentration with the Low Carb diet was 58% that of the CRPC-bearing mice on the Western diet. Enzymes in the steroidogenesis pathway were directly impacted and tumors isolated from intact mice on the Low Carb diet had higher AKR1C3 protein levels and lower HSD17B2 protein levels than intact mice on the Western diet (ARK1C3: P = 0.074; HSD17B2: P = 0.091, with α = 0.1). In contrast, CRPC tumors from mice on Low Carb diets had higher concentrations of both HSD17B2 (P = 0.016) and SRD5A1 (P = 0.058 with α = 0.1) enzymes. There was no correlation between tumor growth in castrated mice for Low Carb diet versus Western diet and (a) serum insulin (b) GH serum levels (c) insulin receptor (IR) or (d) IGF-1R in tumor tissue. Intact mice fed Western diet had higher serum insulin which was associated with significantly higher blood glucose and tumor tissue IR. We conclude that both diet and castration have a significant impact on the endocrinology of mice bearing LNCaP xenograft tumors. The observed effects of diet on cholesterol and steroid regulation impact tumor tissue DHT specifically and are likely to be mechanistic drivers behind the observed tumor growth suppression.

Regulation of local steroidogenesis in the brain and in prostate cancer: lessons learned from interdisciplinary collaboration

Sex steroids play critical roles in the regulation of the brain and many other organs. Traditionally, researchers have focused on sex steroid signaling that involves travel from the gonads via the circulation to intracellular receptors in target tissues. This classic concept has been challenged, however, by the growing number of cases in which steroids are synthesized locally and act locally within diverse tissues. For example, the brain and prostate carcinoma were previously considered targets of gonadal sex steroids, but under certain circumstances, these tissues can upregulate their steroidogenic potential, particularly when circulating sex steroid concentrations are low. We review some of the similarities and differences between local sex steroid synthesis in the brain and prostate cancer. We also share five lessons that we have learned during the course of our interdisciplinary collaboration, which brought together neuroendocrinologists and cancer biologists. These lessons have important implications for future research in both fields.

Synthesis of non-prenyl analogues of baccharin as selective and potent inhibitors for aldo-keto reductase 1C3

Inhibitors of a human member (AKR1C3) of the aldo-keto reductase superfamily are regarded as promising therapeutics for the treatment of prostatic and breast cancers. Baccharin [3-prenyl-4-(dihydrocinnamoyloxy)cinnamic acid], a component of propolis, was shown to be both potent (Ki 56 nM) and highly isoform-selective inhibitor of AKR1C3. In this study, a series of derivatives of baccharin were synthesized by replacing the 3-prenyl moiety with aryl and alkyl ether moieties, and their inhibitory activities for the enzyme were evaluated. Among them, two benzyl ether derivatives, 6m and 6n, showed an equivalent inhibitory potency to baccharin. The molecular docking of 6m in AKR1C3 has allowed the design and synthesis of (E)-3-{3-[(3-hydroxybenzyl)oxy]-4-[(3-phenylpropanoyl)oxy]phenyl}acrylic acid (14) with improved potency (Ki 6.4 nM) and selectivity comparable to baccharin. Additionally, 14 significantly decreased the cellular metabolism of androsterone and cytotoxic 4-oxo-2-nonenal by AKR1C3 at much lower concentrations than baccharin.

Molecular characterization of enzalutamide-treated bone metastatic castration-resistant prostate cancer

BACKGROUND

Enzalutamide is a novel antiandrogen with proven efficacy in metastatic castration-resistant prostate cancer (mCRPC).

OBJECTIVE

To evaluate enzalutamide's effects on cancer and on androgens in blood and bone marrow, and associate these with clinical observations.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective phase 2 study, 60 patients with bone mCRPC received enzalutamide 160mg orally daily and had transilial bone marrow biopsies before treatment and at 8 wk of treatment.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Androgen signaling components (androgen receptor [AR], AR splice variant 7 (ARV7), v-ets avian erythroblastosis virus E26 oncogene homolog [ERG], cytochrome P450, family 17, subfamily A, polypeptide 1 [CYP17]) and molecules implicated in mCRPC progression (phospho-Met, phospho-Src, glucocorticoid receptor, Ki67) were assessed by immunohistochemistry; testosterone, cortisol, and androstenedione concentrations were assessed by liquid chromatography-tandem mass spectrometry; AR copy number was assessed by real-time polymerase chain reaction. Descriptive statistics were applied.

RESULTS AND LIMITATIONS

Median time to treatment discontinuation was 22 wk (95% confidence interval, 19.9-29.6). Twenty-two (37%) patients exhibited primary resistance to enzalutamide, discontinuing treatment within 4 mo. Maximal prostate-specific antigen (PSA) decline ≥ 50% and ≥ 90% occurred in 27 (45%) and 13 (22%) patients, respectively. Following 8 wk of treatment, bone marrow and circulating testosterone levels increased. Pretreatment tumor nuclear AR overexpression (> 75%) and CYP17 (> 10%) expression were associated with benefit (p = 0.018). AR subcellular localization shift from the nucleus was confirmed in eight paired samples (with PSA decline) of 23 evaluable paired samples. Presence of an ARV7 variant was associated with primary resistance to enzalutamide (p = 0.018). Limited patient numbers warrant further validation.

CONCLUSIONS

The observed subcellular shift of AR from the nucleus and increased testosterone concentration provide the first evidence in humans that enzalutamide suppresses AR signaling while inducing an adaptive feedback. Persistent androgen signaling in mCRPC was predictive of benefit and ARV7 was associated with primary resistance.

PATIENT SUMMARY

We report a first bone biopsy study in metastatic prostate cancer in humans that searched for predictors of outcome of enzalutamide therapy. Benefit is linked to a pretreatment androgen-signaling signature.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01091103.

17-Hydroxyprogesterone in children, adolescents and adults

17-Hydroxyprogesterone (17-OHP) is an intermediate steroid in the adrenal biosynthetic pathway from cholesterol to cortisol and is the substrate for steroid 21-hydroxylase. An inherited deficiency of 21-hydroxylase leads to greatly increased serum concentrations of 17-OHP, while the absence of cortisol synthesis causes an increase in adrenocorticotrophic hormone. The classical congenital adrenal hyperplasia (CAH) presents usually with virilisation of a girl at birth. Affected boys and girls can have renal salt loss within a few days if aldosterone production is also compromised. Diagnosis can be delayed in boys. A non-classical form of congenital adrenal hyperplasia (NC-CAH) presents later in life usually with androgen excess. Moderately raised or normal 17-OHP concentrations can be seen basally but, if normal and clinical suspicion is high, an ACTH stimulation test will show 17-OHP concentrations (typically >30 nmol/L) above the normal response. NC-CAH is more likely to be detected clinically in females and may be asymptomatic particularly in males until families are investigated. The prevalence of NC-CAH in women with androgen excess can be up to 9% according to ethnic background and genotype. Mutations in the 21-hydroxylase genes in NC-CAH can be found that have less deleterious effects on enzyme activity. Other less-common defects in enzymes of cortisol synthesis can be associated with moderately elevated 17-OHP. Precocious puberty, acne, hirsutism and subfertility are the commonest features of hyperandrogenism. 17-OHP is a diagnostic marker for CAH but opinions differ on the role of 17OHP or androstenedione in monitoring treatment with renin in the salt losing form. This review considers the utility of 17-OHP measurements in children, adolescents and adults.

Androgens in pregnancy: roles in parturition

BACKGROUND

Understanding the physiology of pregnancy enables effective management of pregnancy complications that could otherwise be life threatening for both mother and fetus. A functional uterus (i) retains the fetus in utero during pregnancy without initiating stretch-induced contractions and (ii) is able to dilate the cervix and contract the myometrium at term to deliver the fetus. The onset of labour is associated with successful cervical remodelling and contraction of myometrium, arising from concomitant activation of uterine immune and endocrine systems. A large body of evidence suggests that actions of local steroid hormones may drive changes occurring in the uterine microenvironment at term. Although there have been a number of studies considering the potential role(s) played by progesterone and estrogen at the time of parturition, the bio-availability and effects of androgens during pregnancy have received less scrutiny. The aim of this review is to highlight potential roles of androgens in the biology of pregnancy and parturition.

METHODS

A review of published literature was performed to address (i) androgen concentrations, including biosynthesis and clearance, in maternal and fetal compartments throughout gestation, (ii) associations of androgen concentrations with adverse pregnancy outcomes, (iii) the role of androgens in the physiology of cervical remodelling and finally (iv) the role of androgens in the physiology of myometrial function including any impact on contractility.

RESULTS

Some, but not all, androgens increase throughout gestation in maternal circulation. The effects of this increase are not fully understood; however, evidence suggests that increased androgens might regulate key processes during pregnancy and parturition. For example, androgens are believed to be critical for cervical remodelling at term, in particular cervical ripening, via regulation of cervical collagen fibril organization. Additionally, a number of studies highlight potential roles for androgens in myometrial relaxation via non-genomic, AR-independent pathways critical for the pregnancy reaching term. Understanding of the molecular events leading to myometrial relaxation is an important step towards development of novel targeted tocolytic drugs.

CONCLUSIONS

The increase in androgen levels throughout gestation is likely to be important for establishment and maintenance of pregnancy and initiation of parturition. Further investigation of the underlying mechanisms of androgen action on cervical remodelling and myometrial contractility is needed. The insights gained may facilitate the development of new therapeutic approaches to manage pregnancy complications such as preterm birth.

A gain-of-function mutation in DHT synthesis in castration-resistant prostate cancer

Growth of prostate cancer cells is dependent upon androgen stimulation of the androgen receptor (AR). Dihydrotestosterone (DHT), the most potent androgen, is usually synthesized in the prostate from testosterone secreted by the testis. Following chemical or surgical castration, prostate cancers usually shrink owing to testosterone deprivation. However, tumors often recur, forming castration-resistant prostate cancer (CRPC). Here, we show that CRPC sometimes expresses a gain-of-stability mutation that leads to a gain-of-function in 3β-hydroxysteroid dehydrogenase type 1 (3βHSD1), which catalyzes the initial rate-limiting step in conversion of the adrenal-derived steroid dehydroepiandrosterone to DHT. The mutation (N367T) does not affect catalytic function, but it renders the enzyme resistant to ubiquitination and degradation, leading to profound accumulation. Whereas dehydroepiandrosterone conversion to DHT is usually very limited, expression of 367T accelerates this conversion and provides the DHT necessary to activate the AR. We suggest that 3βHSD1 is a valid target for the treatment of CRPC.

11β-hydroxyandrostenedione returns to the steroid arena: biosynthesis, metabolism and function

The biological significance of 11β-hydroxyandrostenedione (11OHA4) has eluded researchers for the past six decades. It is now known that 11OHA4 is biosynthesized in the androgen arm of the adrenal steroidogenesis pathway and subsequently metabolized by steroidogenic enzymes in vitro, serving as precursor to recognized and novel androgenic steroids. These in vitro findings extend beyond the adrenal, suggesting that 11OHA4 could be metabolized in steroid-responsive peripheral tissues, as is the case for androgen precursor metabolites of adrenal origin. The significance thereof becomes apparent when considering that the metabolism of 11OHA4 in LNCaP androgen dependent prostate cancer cells yields androgenic steroid metabolites. It is thus possible that 11OHA4 may be metabolized to yield ligands for steroid receptors in not only the prostate but also in other steroid-responsive tissues. Future investigations of 11OHA4 may therefore characterize it as a vital steroid with far-reaching physiological consequences. An overview of the research on 11OHA4 since its identification in 1953 will be presented, with specific focus on the most recent works that have advanced our understanding of its biological role, thereby underscoring its relevance in health and disease.

11β-Hydroxydihydrotestosterone and 11-ketodihydrotestosterone, novel C19 steroids with androgenic activity: a putative role in castration resistant prostate cancer?

Adrenal C19 steroids, dehydroepiandrostenedione (DHEA(S)) and androstenedione (A4), play a critical role in castration resistant prostate cancer (CRPC) as they are metabolised to dihydrotestosterone (DHT), via testosterone (T), or via the alternate 5α-dione pathway, bypassing T. Adrenal 11OHA4 metabolism in CRPC is, however, unknown. We present a novel pathway for 11OHA4 metabolism in CRPC leading to the production of 11ketoT (11KT) and novel 5α-reduced C19 steroids - 11OH-5α-androstanedione, 11keto-5α-androstanedione, 11OHDHT and 11ketoDHT (11KDHT). The pathway was validated in the androgen-dependent prostate cancer cell line, LNCaP. Androgen receptor (AR) transactivation studies showed that while 11KT and 11OHDHT act as a partial AR agonists, 11KDHT is a full AR agonist exhibiting similar activity to DHT at 1nM. Our data demonstrates that, while 11OHA4 has negligible androgenic activity, its metabolism to 11KT and 11KDHT yields androgenic compounds which may be implicated, together with A4 and DHEA(S), in driving CRPC in the absence of testicular T.

Genome-wide association study identifies a new locus JMJD1C at 10q21 that may influence serum androgen levels in men

Circulating androgen levels are often used as indicators of physiological or pathological conditions. More than half of the variance for circulating androgen levels is thought to be genetically influenced. A genome-wide association study (GWAS) has identified two loci, SHBG at 17p13 and FAM9B at Xp22, for serum testosterone (T) levels; however, these explain only a small fraction of inter-individual variability. To identify additional genetic determinants of androgen levels, a GWAS of baseline serum T and dihydrotestosterone (DHT) levels was conducted in 3225 men of European ancestry from the REduction by DUtasteride of Prostate Cancer Events (REDUCE) study. Cross-validation was used to confirm the observed associations between the drug (n = 1581) and placebo (n = 1644) groups of REDUCE. In addition to confirming the associations of two known loci with serum T levels (rs727428 in SHBG: P = 1.26 × 10(-12); rs5934505 in FAM9B: P = 1.61 × 10(-8)), we identified a new locus, JMJD1C at 10q21 that was associated with serum T levels at a genome-wide significance level (rs10822184: P = 1.12 × 10(-8)). We also observed that the SHBG locus was associated with serum DHT levels (rs727428: P = 1.47 × 10(-11)). Moreover, two additional variants in SHBG [rs72829446, in strong linkage equilibrium with the missense variant D356N (rs6259), and rs1799941] were also independently associated with circulating androgen levels in a statistical scale. These three loci (JMJD1C, SHBG and FAM9B) were estimated to account for ~5.3 and 4.1% of the variance of serum T and DHT levels. Our findings may provide new insights into the regulation of circulating androgens and potential targets for androgen-based therapy.

Selective inhibition of human type-5 17β-hydroxysteroid dehydrogenase (AKR1C3) by baccharin, a component of Brazilian propolis

The human aldo-keto reductase (AKR) 1C3, also known as type-5 17β-hydroxysteroid dehydrogenase and prostaglandin F synthase, has been suggested as a therapeutic target in the treatment of prostate and breast cancers. In this study, AKR1C3 inhibition was examined by Brazilian propolis-derived cinnamic acid derivatives that show potential antitumor activity, and it was found that baccharin (1) is a potent competitive inhibitor (K(i) 56 nM) with high selectivity, showing no significant inhibition toward other AKR1C isoforms (AKR1C1, AKR1C2, and AKR1C4). Molecular docking and site-directed mutagenesis studies suggested that the nonconserved residues Ser118, Met120, and Phe311 in AKR1C3 are important for determining the inhibitory potency and selectivity of 1. The AKR1C3-mediated metabolism of 17-ketosteroid and farnesal in cancer cells was inhibited by 1, which was effective from 0.2 μM with an IC(50) value of about 30 μM. Additionally, 1 suppressed the proliferation of PC3 prostatic cancer cells stimulated by AKR1C3 overexpression. This study is the first demonstration that 1 is a highly selective inhibitor of AKR1C3.

Effect of CYP17 and PSA gene polymorphisms on prostate cancer risk and circulating PSA levels in the Slovak population

Cytochrome P-450c17α (CYP17) and prostate-specific antigen (PSA) genes, which are involved in the androgen metabolism cascade, have been studied as possible candidates for genetic influences on prostate cancer development. Contradictory results prompted us to evaluate the frequencies of polymorphisms in the CYP17 and PSA genes as well as the association between these genetic variants and serum PSA levels in prostate cancer patients and men routinely screened for prostate cancer with PSA in the Slovak male population. The CYP17 and PSA polymorphisms were determined by the PCR-RFLP analysis in 197 Caucasian prostate cancer patients and 256 Caucasian controls. We did not find any association between the CYP17 and PSA genotypes and prostate cancer risk overall, or by grade. Also the total serum PSA levels in the cases with the AG or AA genotype were not significantly higher than in the men with the GG genotype (P > 0.05). Our study did not provide support for the hypothesized relationship between CYP17 and PSA gene polymorphisms and prostate cancer in the Slovak male population.

Effects of abiraterone acetate on androgen signaling in castrate-resistant prostate cancer in bone

PURPOSE

Persistent androgen signaling is implicated in castrate-resistant prostate cancer (CRPC) progression. This study aimed to evaluate androgen signaling in bone marrow-infiltrating cancer and testosterone in blood and bone marrow and to correlate with clinical observations.

PATIENTS AND METHODS

This was an open-label, observational study of 57 patients with bone-metastatic CRPC who underwent transiliac bone marrow biopsy between October 2007 and March 2010. Patients received oral abiraterone acetate (1 g) once daily and prednisone (5 mg) twice daily. Androgen receptor (AR) and CYP17 expression were assessed by immunohistochemistry, testosterone concentration by mass spectrometry, AR copy number by polymerase chain reaction, and TMPRSS2-ERG status by fluorescent in situ hybridization in available tissues.

RESULTS

Median overall survival was 555 days (95% CI, 440 to 965+ days). Maximal prostate-specific antigen decline ≥ 50% occurred in 28 (50%) of 56 patients. Homogeneous, intense nuclear expression of AR, combined with ≥ 10% CYP17 tumor expression, was correlated with longer time to treatment discontinuation (> 4 months) in 25 patients with tumor-infiltrated bone marrow samples. Pretreatment CYP17 tumor expression ≥ 10% was correlated with increased bone marrow aspirate testosterone. Blood and bone marrow aspirate testosterone concentrations declined to less than picograms-per-milliliter levels and remained suppressed at progression.

CONCLUSION

The observed pretreatment androgen-signaling signature is consistent with persistent androgen signaling in CRPC bone metastases. This is the first evidence that abiraterone acetate achieves sustained suppression of testosterone in both blood and bone marrow aspirate to less than picograms-per-milliliter levels. Potential admixture of blood with bone marrow aspirate limits our ability to determine the origin of measured testosterone.

Potential prostate cancer drug target: bioactivation of androstanediol by conversion to dihydrotestosterone

High-affinity binding of dihydrotestosterone (DHT) to the androgen receptor (AR) initiates androgen-dependent gene activation, required for normal male sex development in utero, and contributes to prostate cancer development and progression in men. Under normal physiologic conditions, DHT is synthesized predominantly by 5α-reduction of testosterone, the major circulating androgen produced by the testis. During androgen deprivation therapy, intratumoral androgen production is sufficient for AR activation and prostate cancer growth, even though circulating testicular androgen levels are low. Recent studies indicate that the metabolism of 5α-androstane-3α, 17β-diol by 17β-hydroxysteroid dehydrogenase 6 in benign prostate and prostate cancer cells is a major biosynthetic pathway for intratumoral synthesis of DHT, which binds AR and initiates transactivation to promote prostate cancer growth during androgen deprivation therapy. Drugs that target the so-called backdoor pathway of DHT synthesis provide an opportunity to enhance clinical response to luteinizing-hormone-releasing hormone (LHRH) agonists or antagonists, AR antagonists, and inhibitors of 5α-reductase enzymes (finasteride or dutasteride), and other steroid metabolism enzyme inhibitors (ketoconazole or the recently available abiraterone acetate).

Transcriptional regulation of type 11 17β-hydroxysteroid dehydrogenase expression in prostate cancer cells

Type 11 hydroxysteroid (17-beta) dehydrogenase (HSD17B11) catalyzes the conversion of 5α-androstan-3α,17β-diol into androsterone suggesting that it may play an important role in androgen metabolism. We previously described that overexpression of C/EBPα or C/EBPβ induced HSD17B11 expression in HepG2 cells but this process was not mediated by the CCAAT boxes located within its proximal promoter region. Here, we study HSD17B11 transcriptional regulation in prostate cancer (PC) cells. Transfection experiments showed that the region -107/+18 is sufficient for promoter activity in PC cells. Mutagenesis analysis indicated that Sp1 and C/EBP binding sites found in this region are essential for promoter activity. Additional experiments demonstrated that ectopic expression of Sp1 and C/EBPα upregulated HSD17B11 expression only in PC cell lines. Through DAPA and ChIP assays, specific recruitment of Sp1 and C/EBPα to the HSD17B11 promoter was detected. These results show that HSD17B11 transcription in PC cells is regulated by Sp1 and C/EBPα.

Targeting 5α-reductase for prostate cancer prevention and treatment

Testosterone is the most abundant circulating androgen, and can be converted to dihydrotestosterone (DHT), a more potent androgen, by the 5α-reductase enzymes in target tissues. Current treatments for prostate cancer consist of reducing androgen levels by chemical or surgical castration or pure antiandrogen therapy that directly targets the androgen receptor (AR). Although these therapies reduce tumor burden and AR activity, the cancer inevitably recurs within 18-30 months. An approach targeting the androgen-AR axis at different levels could, therefore, improve the efficacy of prostate cancer therapy. Inhibition of 5α-reductase is one such approach; however, the two largest trials to investigate the use of the 5α-reductase inhibitors (5ARIs) finasteride and dutasteride in patients with prostate cancer have shown that, although the incidence of cancer was reduced by 5ARI treatment, those cancers that were detected were more aggressive than in patients treated with placebo. Thus, the best practice for using these drugs to prevent and treat prostate cancer remains unclear.

Late-onset male hypogonadism: clinical and laboratory evaluation

Late-onset male hypogonadism (LOH) is a clinical and biochemical syndrome associated with advancing age and characterised by low serum testosterone concentrations. An understanding of the physiology of androgens in the ageing man is essential for the appropriate diagnosis of LOH. Clinical assessment of androgen status relevant to clinical biochemists and chemical pathologists is outlined in this review. Laboratory investigations of androgen status in men are not without pitfalls and the authors highlight problems associated with measuring and calculating serum testosterone and its fractions, the interpretation of which can be problematic. Current clinical guidelines and recommendations regarding the diagnosis and monitoring of LOH are also summarised.

SRD5A2 is associated with increased cortisol metabolism in schizophrenia spectrum disorders

OBJECTIVE

Dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis is documented in bipolar disorder and schizophrenia, but the mechanism is unclear; recently, increased activity of cortisol metabolizing enzymes was indicated in these disorders. We investigated whether five genes involved in cortisol metabolism were associated with altered activity of cortisol metabolizing enzymes in bipolar disorder (BD) and schizophrenia spectrum disorders (SCZ).

METHODS

A case-control sample of subjects with BD (N=213), SCZ (N=274) and healthy controls (N=370) from Oslo, Norway, were included and genotyped from 2003 to 2008. A sub-sample (healthy controls: N=151; SCZ: N=40; BD: N=39) had estimated enzyme activities based on measurements of urinary free cortisol, urinary free cortisone and metabolites. A total of 102 single nucleotide polymorphisms (SNPs) in the SRD5A1, SRD5A2, AKR1D1, HSD11B1 and HSD11B2 genes were genotyped, and significant SNPs analyzed in the sub-sample.

RESULTS

There was a significant association of rs6732223 in SRD5A2 (5α-reductase) with SCZ (p=0.0043, Bonferroni corrected p=0.030, T risk allele). There was a significantly increased 5α-reductase activity associated with rs6732223 (T allele) within the SCZ group (p=0.011).

CONCLUSIONS

The present data suggest an interaction between SCZ and SRD5A2 variants coding for the enzyme 5α-reductase, giving rise to increased 5α-reductase activity in SCZ. The findings may have implications for cortisol metabolizing enzymes as possible drug targets.