Intracrinology: role of the family of 17 beta-hydroxysteroid dehydrogenases in human physiology and disease

Synthesis and characterization of targeted 17β-hydroxysteroid dehydrogenase type 7 inhibitors

Sex steroid hormones such as estrogen estradiol (E2) and androgen dihydrotestosterone (DHT) are involved in the development of hormone-dependent cancers. Blockade of 17β-hydroxysteroid dehydrogenase type 7 (17β-HSD7), a member of the short chain dehydrogenase/reductase superfamily, is thought to decrease E2 levels while increasing those of DHT. Therefore, its unique double action makes this enzyme as an interesting drug target for treatment of breast cancer. The chemical synthesis, molecular characterization, and preliminary biological evaluation as 17β-HSD7 inhibitors of novel carbamate derivatives 3 and 4 are described. Like previous 17β-HSD7 inhibitors 1 and 2, compounds 3 and 4 bear a hydrophobic nonyl side chain at the C-17β position of a 4-aza-5α-androstane nucleus, but compound 3 has an oxygen atom replacing the CH2 in the steroid A-ring C-2 position, while compound 4 has a C17-spiranic E-ring containing a carbamate function. They both inhibited the in vitro transformation of estrone (E1) into E2 by 17β-HSD7, but the introduction of a (17 R)-spirocarbamate is preferable to replacing C-2 methylene with an oxygen atom since compound 4 (IC50 = 63 nM) is an inhibitor 14 times more powerful than compound 3 (IC50 = 900 nM). Furthermore, when compared to the reference inhibitor 1 (IC50 = 111 nM), the use of a C17-spiranic E-ring made it possible to introduce differently the hydrophobic nonyl side chain, without reducing the inhibitory activity.

How Per- and Poly-Fluoroalkyl Substances Affect Gamete Viability and Fertilization Capability: Insights from the Literature

There has been emerging research linking per- and poly-fluoroalkyl substances (PFAS) to gamete viability and fertility. PFAS, prevalent in the environment and water supplies, undergo slow degradation due to their C-F bond and a long half-life (2.3-8.5 years). In females, PFAS inhibit the hypothalamic-pituitary-gonadal (HPG) axis, reducing follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels, leading to the inhibition of androgen and estradiol production. PFAS have been found to cause detrimental effects on egg quality through impairing folliculogenesis. In males, PFAS can impair sperm motility and morphology: two fundamental qualities of successful fertilization. PFAS exposure has been proven to inhibit testosterone production, sperm capacitation, and acrosomal reaction. After fertilization, the results of PFAS exposure to embryos have also been investigated, showing reduced development to the blastocyst stage. The aim of this review is to report the main findings in the literature on the impact of PFAS exposure to gamete competency and fertilization capability by highlighting key studies on both male and female fertility. We report that there is significant evidence demonstrating the negative impacts on fertility after PFAS exposure. At high doses, these environmentally abundant and widespread compounds can significantly affect human fertility.

17β-Hydroxysteroid dehydrogenases types 1 and 2: Enzymatic assays based on radiometric and mass-spectrometric detection

The 17β-hydroxysteroid dehydrogenase type 1 (HSD17B1) has a key role in estrogen biosynthesis as it catalyzes the reduction of estrone to the most potent estrogen, estradiol. Estradiol has a high affinity for estrogen receptors and thus stimulates their transactivation, which leads to cell proliferation and numerous other effects. HSD17B2 catalyzes the oxidation of estradiol to the less potent estrone, thereby decreasing estrogen receptor activation, which results in reduction of estrogen-associated effects. HSD17B1 and HSD17B2 overexpressing E.coli homogenates or recombinant enzymes can be used for screening and development of drugs against various pathologies such as cancer, endometriosis or osteoporosis. Here we describe the preparation of HSD17B1 and HSD17B2 bacterial homogenates and purified recombinant HSD17B1 protein as enzyme sources as well as enzymatic assays based on radiometric and mass-spectrometric detection for enzyme characterization.

Transitional cell metaplasia of the uterine cervix: A histopathological and immunohistochemical analysis suggesting a possible role of androgenic conversion during urothelial-like differentiation in peri/postmenopausal women

Transitional cell metaplasia (TCM) of the uterine cervix and vagina is typically seen in patients with adrenogenital syndrome with high serum androgen levels and in those under androgen treatment as well as in some peri/postmenopausal women. Considering that TCM occurs in patients with increased serum androgen levels, a microenvironment with altered sex hormones might be involved in the urothelial-like differentiation observed in TCM. To investigate a histogenetic role of androgen in TCM development, we compared the distribution patterns and intensity of androgen receptor (AR), estrogen receptor (ER), GATA3 (a transcription factor involved in androgen regulation), Ki-67, and AKR1C3 (an enzyme involved in androgen biosynthesis) expression in normal exocervical mucosa in young women (n = 25), senile atrophy (n = 23), and TCM (n = 29). In TCM, AR, ER, AKR1C3, and GATA3, expression was stronger and significantly increased upward into the intermediate and superficial layers compared with the senile atrophic mucosa and normal mucosa in young women. The epithelial layer in TCM is thicker than that in senile atrophic mucosa, although both conditions may occur in the same age group. Proliferation in TCM was significantly lower than that in young women but slightly higher than that in senile atrophy. Considering the conversion activity of AKR1C3, thicker epithelial layers in TCM compared with those in senile atrophy might be due to increased conversion of androstenedione to testosterone via increased AKR1C3 activity, increased conversion of testosterone to 17β-estradiol by aromatization, and AR activation.

Perfluoroalkyl Chemicals and Male Reproductive Health: Do PFOA and PFOS Increase Risk for Male Infertility?

Poly- and perfluoroalkyl substances (PFAS) are manmade synthetic chemicals which have been in existence for over 70 years. Though they are currently being phased out, their persistence in the environment is widespread. There is increasing evidence linking PFAS exposure to health effects, an issue of concern since PFAS such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) bioaccumulate in humans, with a half-life of years. Many epidemiological studies suggest that, worldwide, semen quality has decreased over the past several decades. One of the most worrying effects of PFOS and PFOA is their associations with lower testosterone levels, similar to clinical observations in infertile men. This review thus focuses on PFOS/PFOA-associated effects on male reproductive health. The sources of PFAS in drinking water are listed. The current epidemiological studies linking increased exposure to PFAS with lowered testosterone and semen quality, and evidence from rodent studies supporting their function as endocrine disruptors on the reproductive system, exhibiting non-monotonic dose responses, are noted. Finally, their mechanisms of action and possible toxic effects on the Leydig, Sertoli, and germ cells are discussed. Future research efforts must consider utilizing better human model systems for exposure, using more accurate PFAS exposure susceptibility windows, and improvements in statistical modeling of data to account for the endocrine disruptor properties of PFAS.

Identification of significantly mutated subnetworks in the breast cancer genome

Recent studies showed that somatic cancer mutations target genes that are in specific signaling and cellular pathways. However, in each patient only a few of the pathway genes are mutated. Current approaches consider only existing pathways and ignore the topology of the pathways. For this reason, new efforts have been focused on identifying significantly mutated subnetworks and associating them with cancer characteristics. We applied two well-established network analysis approaches to identify significantly mutated subnetworks in the breast cancer genome. We took network topology into account for measuring the mutation similarity of a gene-pair to allow us to infer the significantly mutated subnetworks. Our goals are to evaluate whether the identified subnetworks can be used as biomarkers for predicting breast cancer patient survival and provide the potential mechanisms of the pathways enriched in the subnetworks, with the aim of improving breast cancer treatment. Using the copy number alteration (CNA) datasets from the METABRIC (Molecular Taxonomy of Breast Cancer International Consortium) study, we identified a significantly mutated yet clinically and functionally relevant subnetwork using two graph-based clustering algorithms. The mutational pattern of the subnetwork is significantly associated with breast cancer survival. The genes in the subnetwork are significantly enriched in retinol metabolism KEGG pathway. Our results show that breast cancer treatment with retinoids may be a potential personalized therapy for breast cancer patients since the CNA patterns of the breast cancer patients can imply whether the retinoids pathway is altered. We also showed that applying multiple bioinformatics algorithms at the same time has the potential to identify new network-based biomarkers, which may be useful for stratifying cancer patients for choosing optimal treatments.

Physiology of the Endometrium and Regulation of Menstruation

The physiological functions of the uterine endometrium (uterine lining) are preparation for implantation, maintenance of pregnancy if implantation occurs, and menstruation in the absence of pregnancy. The endometrium thus plays a pivotal role in reproduction and continuation of our species. Menstruation is a steroid-regulated event, and there are alternatives for a progesterone-primed endometrium, i.e., pregnancy or menstruation. Progesterone withdrawal is the trigger for menstruation. The menstruating endometrium is a physiological example of an injured or “wounded” surface that is required to rapidly repair each month. The physiological events of menstruation and endometrial repair provide an accessible in vivo human model of inflammation and tissue repair. Progress in our understanding of endometrial pathophysiology has been facilitated by modern cellular and molecular discovery tools, along with animal models of simulated menses. Abnormal uterine bleeding (AUB), including heavy menstrual bleeding (HMB), imposes a massive burden on society, affecting one in four women of reproductive age. Understanding structural and nonstructural causes underpinning AUB is essential to optimize and provide precision in patient management. This is facilitated by careful classification of causes of bleeding. We highlight the crucial need for understanding mechanisms underpinning menstruation and its aberrations. The endometrium is a prime target tissue for selective progesterone receptor modulators (SPRMs). This class of compounds has therapeutic potential for the clinical unmet need of HMB. SPRMs reduce menstrual bleeding by mechanisms still largely unknown. Human menstruation remains a taboo topic, and many questions concerning endometrial physiology that pertain to menstrual bleeding are yet to be answered.

Meta-Analysis of steroid-converting enzymes and related receptors in prostate cancer suggesting novel combined therapies

Androgen receptor (AR) signaling is essential for prostate cancer (PC) progression and treatment. Experiments have demonstrated that the intratumoral androgen levels are not affected by circulating androgen levels, but rather modulated by local steroid-converting enzyme activities. The expression modulation status of human steroid-converting enzymes and nuclear receptors are of great promise to identify novel therapeutic targets. Meta-analysis was performed with 9 cohorts (1093 specimens) from Gene Expression Omnibus, 16 cohorts (933 specimens) from Oncomine and the TCGA cohort (550 specimens). We found significant up regulation of 5α-reductase type 1 and type 3 in both primary and metastatic PC, together with the down regulation of AKR1C2 in primary PC, contributing to the high intratumoral DHT levels. The expression of AR in metastatic PC was up regulated, indicating the importance of AR signaling in the progression of this cancer. The down regulations of HSD11B1 and NR3C1 in primary and metastatic PC may diminish the anti-inflammation and anti-proliferation effects of glucocorticoids signaling. Furthermore, the decrease of progesterone receptor (PGR) expression in primary and metastatic PC was also observed, relieving the suppression effect of PGR on PC proliferation. The clinical evidences of the remarkable expression modulation of steroid-converting enzymes and receptors in PC may indicate novel combined treatment against this highly incident cancer.

Intracrinology-revisited and prostate cancer

The formation of steroid hormones in peripheral target tissues is referred to as their intracrine formation. This process occurs in hormone dependent malignancies such as prostate and breast cancer in which the disease can be either castrate resistant or occur post-menopausally, respectively. In these instances, the major precursor steroid of androgens and estrogens is dehydroepiandrosterone (DHEA) and DHEA-SO4. This article reviews the major pathways by which adrenal steroids are converted to the potent male sex hormones, testosterone (T) and 5α-dihydrotestosterone (5α-DHT) and the discrete enzyme isoforms involved in castration resistant prostate cancer. Previous studies have mainly utilized radiotracers to investigate these pathways but have not used prevailing concentrations of precursors found in castrate male human serum. In addition, the full power of stable-isotope dilution liquid chromatography tandem mass spectrometry has not been applied routinely. Furthermore, it is clear that adaptive responses occur in the transporters and enzyme isoforms involved in response to androgen deprivation therapy that need to be considered.

Inhibitors of 17β-hydroxysteroid dehydrogenase type 1, 2 and 14: Structures, biological activities and future challenges

During the past 25 years, the modulation of estrogen action by inhibition of 17β-hydroxysteroid dehydrogenase types 1 and 2 (17β-HSD1 and 17β-HSD2), respectively, has been pursued intensively. In the search for novel treatment options for estrogen-dependent diseases (EDD) and in order to explore estrogenic signaling pathways, a large number of steroidal and nonsteroidal inhibitors of these enzymes has been described in the literature. The present review gives a survey on the development of inhibitor classes as well as the structural formulas and biological properties of their most interesting representatives. In addition, rationally designed dual inhibitors of both 17β-HSD1 and steroid sulfatase (STS) as well as the first inhibitors of 17β-HSD14 are covered.

Structural and Functional Biology of Aldo-Keto Reductase Steroid-Transforming Enzymes

Aldo-keto reductases (AKRs) are monomeric NAD(P)(H)-dependent oxidoreductases that play pivotal roles in the biosynthesis and metabolism of steroids in humans. AKR1C enzymes acting as 3-ketosteroid, 17-ketosteroid, and 20-ketosteroid reductases are involved in the prereceptor regulation of ligands for the androgen, estrogen, and progesterone receptors and are considered drug targets to treat steroid hormone-dependent malignancies and endocrine disorders. In contrast, AKR1D1 is the only known steroid 5β-reductase and is essential for bile-acid biosynthesis, the generation of ligands for the farnesoid X receptor, and the 5β-dihydrosteroids that have their own biological activity. In this review we discuss the crystal structures of these AKRs, their kinetic and catalytic mechanisms, AKR genomics (gene expression, splice variants, polymorphic variants, and inherited genetic deficiencies), distribution in steroid target tissues, roles in steroid hormone action and disease, and inhibitor design.

Canonical and Noncanonical Androgen Metabolism and Activity

Androgens are critical drivers of prostate cancer. In this chapter we first discuss the canonical pathways of androgen metabolism and their alterations in prostate cancer progression, including the classical, backdoor and 5α-dione pathways, the role of pre-receptor DHT metabolism, and recent findings on oncogenic splicing of steroidogenic enzymes. Next, we discuss the activity and metabolism of non-canonical 11-oxygenated androgens that can activate wild-type AR and are less susceptible to glucuronidation and inactivation than the canonical androgens, thereby serving as an under-recognized reservoir of active ligands. We then discuss an emerging literature on the potential non-canonical role of androgen metabolizing enzymes in driving prostate cancer. We conclude by discussing the potential implications of these findings for prostate cancer progression, particularly in context of new agents such as abiraterone and enzalutamide, which target the AR-axis for prostate cancer therapy, including mechanisms of response and resistance and implications of these findings for future therapy.

Endometrial Intracrinology: Oestrogens, Androgens and Endometrial Disorders

Peripheral tissue metabolism of steroids (intracrinology) is now accepted as a key way in which tissues, such as the endometrium, can utilise inactive steroids present in the blood to respond to local physiological demands and 'fine-tune' the activation or inhibition of steroid hormone receptor-dependent processes. Expression of enzymes that play a critical role in the activation and inactivation of bioactive oestrogens (E1, E2) and androgens (A4, T, DHT), as well as expression of steroid hormone receptors, has been detected in endometrial tissues and cells recovered during the menstrual cycle. There is robust evidence that increased expression of aromatase is important for creating a local microenvironment that can support a pregnancy. Measurement of intra-tissue concentrations of steroids using liquid chromatography⁻tandem mass spectrometry has been important in advancing our understanding of a role for androgens in the endometrium, acting both as active ligands for the androgen receptor and as substrates for oestrogen biosynthesis. The emergence of intracrinology, associated with disordered expression of key enzymes such as aromatase, in the aetiology of common women's health disorders such as endometriosis and endometrial cancer has prompted renewed interest in the development of drugs targeting these pathways, opening up new opportunities for targeted therapies and precision medicine.

Steroid sulfatase inhibition success and limitation in breast cancer clinical assays: An underlying mechanism

Steroid sulfatase is detectable in most hormone-dependent breast cancers. STX64, an STS inhibitor, induced tumor reduction in animal assay. Despite success in phase І clinical trial, the results of phase II trial were not that significant. Breast Cancer epithelial cells (MCF-7 and T47D) were treated with two STS inhibitors (STX64 and EM1913). Cell proliferation, cell cycle, and the concentrations of estradiol and 5α-dihydrotestosterone were measured to determine the endocrinological mechanism of sulfatase inhibition. Comparisons were made with inhibitions of reductive 17β-hydroxysteroid dehydrogenases (17β-HSDs). Proliferation studies showed that DNA synthesis in cancer cells was modestly decreased (approximately 20%), accompanied by an up to 6.5% in cells in the G0/G1 phase and cyclin D1 expression reduction. The concentrations of estradiol and 5α-dihydrotestosterone were decreased by 26% and 3% respectively. However, supplementation of 5α-dihydrotestosterone produced a significant increase (approximately 35.6%) in the anti-proliferative effect of sulfatase inhibition. This study has clarified sex-hormone control by sulfatase in BC, suggesting that the different roles of estradiol and 5α-dihydrotestosterone can lead to a reduction in the effect of sulfatase inhibition when compared with 17β-HSD7 inhibition. This suggests that combined treatment of sulfatase inhibitors with 17β-HSD inhibitors such as the type7 inhibitor could hold promise for hormone-dependent breast cancer.

Methyl jasmonate enhances the radiation sensitivity of esophageal carcinoma cells by inhibiting the 11-ketoprostaglandin reductase activity of AKR1C3

Purpose

In our previous study, we found that AKR1C3 was a radioresistance gene in KY170R cells. Downregulating the expression of AKR1C3 could enhance the radiosensitivity of esophageal carcinoma cells. In this study, we investigated whether methyl jasmonate (MeJ), an inhibitor of Aldo-keto reductase family1 member C3 (AKR1C3), could overcome radiation resistance in AKR1C3 highly expressed cells.

Patients and methods

We used clone formation assays to detect radiosensitivity effects. Flow cytometry assays were used to detect reactive oxygen species (ROS) accumulation and apoptosis. Enzyme linked immunosorbent assays (ELISAs) were used to detect the concentrations of prostaglandin F2 (PGF2) and prostaglandin D2 (PGD2) in the cells after incubation with MeJ. Western blotting was used to detect AKR1C3 and peroxisome proliferator-activated receptor gamma (PPARγ) expression.

Results

We found that AKR1C3 was highly expressed in radioresistant esophageal carcinoma cells. MeJ inhibited the expression of AKR1C3 and enhanced the radiation sensitivity of esophageal carcinoma cells expressing high levels of AKR1C3 (P<0.05). MeJ could inhibit the 11-ketoprostaglandin reductase activity of AKR1C3 in a dose-dependent manner in KY170R cells. Incubation of KY170R cells with 200 µmol/L of MeJ for 24 h reduced the expression of PGF2 by roughly 30% (P<0.05). The PPAR pathway inhibitor GW9662 prevented the radiation sensitivity enhancement imparted by MeJ. After adding GW9662, there were no significant differences between the radiation sensitivities of MeJ-treated and -untreated KY170R cells (P>0.05). The radiation sensitivity effect of MeJ also depended upon the generation of ROS in KY170R cells; 48 h after irradiation, ROS levels in the MeJ group was twofold higher than in the untreated KY170R cells (P<0.05). The ROS scavenger, N-acetyl cysteine, could reverse the radiosensitivity effects of MeJ (P>0.05).

Conclusion

Our results indicate that MeJ can increase the radiation sensitivity of AKR1C3-overexpressing KY170R cells by inhibiting the 11-ketoprostaglandin reductase activity of AKR1C3 and increasing cellular ROS levels.

SULFATION PATHWAYS: Contribution of intracrine oestrogens to the aetiology of endometriosis

Endometriosis is an incurable hormone-dependent inflammatory disease that causes chronic pelvic pain and infertility characterized by implantation and growth of endometrial tissue outside the uterine cavity. Symptoms have a major impact on the quality of life of patients resulting in socioeconomic, physical and psychological burdens. Although the immune system and environmental factors may play a role in the aetiology of endometriosis, oestrogen dependency is still considered a hallmark of the disorder. The impact of oestrogens such as oestrone and particularly, oestradiol, on the endometrium or endometriotic lesions may be mediated by steroids originating from ovarian steroidogenesis or local intra-tissue production (intracrinology) dependent upon the expression and activity of enzymes that regulate oestrogen biosynthesis and metabolism. Two key pathways have been implicated: while there is contradictory data on the participation of the aromatase enzyme (encoded by CYP19A1), there is increasing evidence that the steroid sulphatase pathway plays a role in both the aetiology and pathology of endometriosis. In this review, we consider the evidence related to the pathways leading to oestrogen accumulation in endometriotic lesions and how this might inform the development of new therapeutic strategies to treat endometriosis without causing the undesirable side effects of current regimes that suppress ovarian hormone production.

Optimal bone fracture repair requires 24R,25-dihydroxyvitamin D3 and its effector molecule FAM57B2

The biological activity of 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3] remains controversial, but it has been suggested that it contributes to fracture healing. Cyp24a1-/- mice, synthesizing no 24R,25(OH)2D3, show suboptimal endochondral ossification during fracture repair, with smaller callus and reduced stiffness. These defects were corrected by 24R,25(OH)2D3 treatment, but not by 1,25-dihydroxyvitamin D3. Microarrays with Cyp24a1-/- callus mRNA identified FAM57B2 as a mediator of the 24R,25(OH)2D3 effect. FAM57B2 produced lactosylceramide (LacCer) upon specific binding of 24R,25(OH)2D3. Fam57b inactivation in chondrocytes (Col2-Cre Fam57bfl/fl) phenocopied the callus formation defect of Cyp24a1-/- mice. LacCer or 24R,25(OH)2D3 injections restored callus volume, stiffness, and mineralized cartilage area in Cyp24a1-null mice, but only LacCer rescued Col2-Cre Fam57bfl/fl mice. Gene expression in callus tissue suggested that the 24R,25(OH)2D3/FAM57B2 cascade affects cartilage maturation. We describe a previously unrecognized pathway influencing endochondral ossification during bone repair through LacCer production upon binding of 24R,25(OH)2D3 to FAM57B2. Our results identify potential new approaches to ameliorate fracture healing.

Androgen Receptor Targeted Treatments of Prostate Cancer: 35 Years of Progress with Antiandrogens

PURPOSE

Antiandrogens inhibit the androgen receptor and have an important role in the treatment of prostate cancer. This review provides a historical perspective on the development and clinical benefit of antiandrogens in the treatment of prostate cancer.

MATERIALS AND METHODS

We searched PubMed® for clinical trials with the search terms antiandrogens and prostate cancer combined with drug names for antiandrogens. This article represents a collaboration of clinical investigators who have made critical scientific contributions leading to the approval of antiandrogens for treating patients with prostate cancer.

RESULTS

Antiandrogens differ in chemical structure and exert varying efficacy and safety profiles. The unfavorable therapeutic index of steroidal antiandrogens led to replacement by safer nonsteroidal agents. Flutamide, nilutamide and bicalutamide, which were designed to target the androgen receptor, were developed primarily for use in combination with castration to provide combined androgen blockade. Modest clinical benefits were observed with the combination of first generation antiandrogens and castration vs castration alone. With increased knowledge of androgen receptor structure and its biological functions a new generation of antiandrogens without agonist activity was designed to provide more potent inhibition of the androgen receptor. Randomized clinical trials in patients with metastatic, castration resistant prostate cancer showed significant survival benefits, which led to the approval of enzalutamide in August 2012. Apalutamide was recently approved while darolutamide is not yet approved in the United States. These next generation antiandrogens are being actively tested in earlier disease states such as nonmetastatic prostate cancer. Evolving knowledge of resistance mechanisms to androgen receptor targeted treatments will stimulate research and drug discovery for additional compounds. Further testing in nonmetastatic castration resistant prostate cancer as well as castration sensitive disease states will hopefully augment our ability to treat a broader spectrum of patients with prostate cancer.

CONCLUSIONS

Antiandrogens have already provided important benefits for prostate cancer treatment. Greater knowledge about the structural and functional biology of the androgen receptor in prostate cancer will facilitate further discovery and development of further improved antiandrogens with enhanced clinical activity in patients with advanced metastatic disease. Testing these new agents earlier in the course of prostate cancer may further improve the survival and quality of life of patients with current local and/or systemic treatment modalities.

The enigmatic relationship between epiphyseal fusion and bone development in primates

Epiphyseal fusion in primates is a process that occurs in a regular sequence spanning a period of years and thus provides biological anthropologists with a useful marker of maturity that can be used to assess age and stage of development. Despite the many studies that have catalogued fusion timing and sequence pattern, comparatively little research has been devoted to understanding why these sequences exist in the first place. Answering this question is not necessarily intuitive; indeed, given that neither taxonomic affinities nor recent adaptations have been clearly defined, it is a challenge to explain this process in evolutionary terms. In all mammals, there is a tendency for the fusion of epiphyses at joints to occur close in sequence, and this has been proposed to relate to locomotor adaptations. Further consideration of the evidence suggests that linking locomotor behavior to sequence data alone is difficult to prove and may require a different type of evidence. Epiphyseal fusion should be considered in the context of other parameters that affect the developing skeleton, including how joint morphology relates to growth in length, as well as other possible morphological constraints. In recent years, developmental biology has been providing a better understanding of the molecular regulators of epiphyseal fusion. At some point in the near future, we may be able to link our understanding of the genetics of fusion timing to the possible selective mechanisms that are responsible for these sequences.

Sex hormones and quantitative ultrasound parameters at the heel in men and women from the general population

Purpose/introduction

The present study investigates potential associations between liquid chromatography-mass spectrometry (LC-MS) measured sex hormones, dehydroepiandrosterone sulphate, sex hormone-binding globulin (SHBG) and bone ultrasound parameters at the heel in men and women from the general population.

Methods

Data from 502 women and 425 men from the population-based Study of Health in Pomerania (SHIP-TREND) were used. Cross-sectional associations of sex hormones including testosterone (TT), calculated free testosterone (FT), dehydroepiandrosterone sulphate (DHEAS), androstenedione (ASD), estrone (E1) and SHBG with quantitative ultrasound (QUS) parameters at the heel, including broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness index (SI) were examined by analysis of variance (ANOVA) and multivariable quantile regression models.

Results

Multivariable regression analysis showed a sex-specific inverse association of DHEAS with SI in men (Beta per SI unit = − 3.08, standard error (SE) = 0.88), but not in women (Beta = − 0.01, SE = 2.09). Furthermore, FT was positively associated with BUA in men (Beta per BUA unit = 29.0, SE = 10.1). None of the other sex hormones (ASD, E1) or SHBG was associated with QUS parameters after multivariable adjustment.

Conclusions

This cross-sectional population-based study revealed independent associations of DHEAS and FT with QUS parameters in men, suggesting a potential influence on male bone metabolism. The predictive role of DHEAS and FT as a marker for osteoporosis in men warrants further investigation in clinical trials and large-scale observational studies.

•

Population-based data of healthy men and women from the general population

•

Sex hormone panel measured by liquid chromatography-mass spectrometry (LC-MS)

•

Associations of dehydroepiandrosterone sulphate and free testosterone with bone ultrasound parameters in men

•

Estrone, androstenedione and SHBG were not associated with bone ultrasound parameters in both sexes.

Substrate inhibition of 17β-HSD1 in living cells and regulation of 17β-HSD7 by 17β-HSD1 knockdown

This study addresses first the role of human 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1) in breast cancer (BC) cells. The enzyme has a high estrone-activating activity that is subject to strong substrate inhibition as shown by enzyme kinetics at the molecular level. We used BC cells to verify this phenomenon in living cells: estrone concentration increase did reduce the reaction with 0.025 to 4μM substrate. Moreover, 5α-dihydrotestosterone (DHT) demonstrated some inhibition of estrogen activation at both the molecular and cellular levels. The presence of DHT did not change the tendency toward substrate inhibition for estrone conversion, but shifted the inhibition toward higher substrate concentrations. Moreover, a binding study demonstrated that both DHT and dehydroepiandrosterone (DHEA) can be bound to the enzyme, thereby supporting the multi-specificity of 17β-HSD1. We then followed the concentrations of estradiol and performed q-RT-PCR measurements of reductive 17β-HSDs after 17β-HSD1 inhibition. The estradiol decrease by the 17β-HSD1 inhibition was demonstrated lending support to this observation. Knockdown and inhibition of 17β-HSD1 produced reduction in estradiol levels and the down-regulation of another reductive enzyme 17β-HSD7, thus "amplifying" the reduction of estradiol by the 17β-HSD1 modulation itself. The critical positioning of 17β-HSD7 in sex-hormone-regulation as well as the mutual regulation of steroid enzymes via estradiol in BC, are clearly demonstrated. Our study demonstrates that fundamental enzymological mechanisms are relevant in living cells. Moreover, further enzyme study in cells is merited to advance biological and medical research. We also demonstrated the central role of 17β-HSD7 in sex-hormone conversion and regulation, supporting it as a novel target for estrogen-dependent (ER+) BC.

TFOS DEWS II Sex, Gender, and Hormones Report

One of the most compelling features of dry eye disease (DED) is that it occurs more frequently in women than men. In fact, the female sex is a significant risk factor for the development of DED. This sex-related difference in DED prevalence is attributed in large part to the effects of sex steroids (e.g. androgens, estrogens), hypothalamic-pituitary hormones, glucocorticoids, insulin, insulin-like growth factor 1 and thyroid hormones, as well as to the sex chromosome complement, sex-specific autosomal factors and epigenetics (e.g. microRNAs). In addition to sex, gender also appears to be a risk factor for DED. "Gender" and "sex" are words that are often used interchangeably, but they have distinct meanings. "Gender" refers to a person's self-representation as a man or woman, whereas "sex" distinguishes males and females based on their biological characteristics. Both gender and sex affect DED risk, presentation of the disease, immune responses, pain, care-seeking behaviors, service utilization, and myriad other facets of eye health. Overall, sex, gender and hormones play a major role in the regulation of ocular surface and adnexal tissues, and in the difference in DED prevalence between women and men. The purpose of this Subcommittee report is to review and critique the nature of this role, as well as to recommend areas for future research to advance our understanding of the interrelationships between sex, gender, hormones and DED.

Riboflavin deficiency induces a significant change in proteomic profiles in HepG2 cells

Riboflavin deficiency is widespread in many regions over the world, especially in underdeveloped countries. In this study, we investigated the effects of riboflavin deficiency on protein expression profiles in HepG2 cells in order to provide molecular information for the abnormalities induced by riboflavin deficiency. HepG2 cells were cultured in media containing different concentrations of riboflavin. Changes of cell viability and apoptosis were assessed. A comparative proteomic analysis was performed using a label-free shotgun method with LC-MS/MS to investigate the global changes of proteomic profiles in response to riboflavin deficiency. Immunoblotting test was used to validate the results of proteomic approach. The cell viability and apoptosis tests showed that riboflavin was vital in maintaining the cytoactivity of HepG2 cells. The label-free proteomic analysis revealed that a total of 37 proteins showing differential expression (±2 fold, p < 0.05) were identified after riboflavin deficiency. Bioinformatics analysis indicated that the riboflavin deficiency caused an up-regulation of Parkinson's disease pathway, steroid catabolism, endoplasmic reticulum stress and apoptotic process, while the fatty acid metabolism, tricarboxylic citrate cycle, oxidative phosphorylation and iron metabolism were down-regulated. These findings provide a molecular basis for the elucidation of the effects caused by riboflavin deficiency.

Inverse Regulation of DHT Synthesis Enzymes 5α-Reductase Types 1 and 2 by the Androgen Receptor in Prostate Cancer

5α-Reductase types 1 and 2, encoded by SRD5A1 and SRD5A2, are the two enzymes that can catalyze the conversion of testosterone to dihydrotestosterone, the most potent androgen receptor (AR) agonist in prostate cells. 5α-Reductase type 2 is the predominant isoform expressed in the normal prostate. However, its expression decreases during prostate cancer (PCa) progression, whereas SRD5A1 increases, and the mechanism underlying this transcriptional regulatory switch is still unknown. Interrogation of SRD5A messenger RNA expression in three publicly available data sets confirmed that SRD5A1 is increased in primary and metastatic PCa compared with nontumoral prostate tissues, whereas SRD5A2 is decreased. Activation of AR, a major oncogenic driver of PCa, induced the expression of SRD5A1 from twofold to fourfold in three androgen-responsive PCa cell lines. In contrast, AR repressed SRD5A2 expression in this context. Chromatin-immunoprecipitation studies established that AR is recruited to both SRD5A1 and SRD5A2 genes following androgen stimulation but initiates transcriptional activation only at SRD5A1 as monitored by recruitment of RNA polymerase II and the presence of the H3K27Ac histone mark. Furthermore, we showed that the antiandrogens bicalutamide and enzalutamide block the AR-mediated regulation of both SRD5A1 and SRD5A2, highlighting an additional mechanism explaining their beneficial effects in patients. In summary, we identified an AR-dependent transcriptional regulation that explains the differential expression of 5α-reductase types 1 and 2 during PCa progression. Our work thus defines a mechanism by which androgens control their own synthesis via differential regulatory control of the expression of SRD5A1 and SRD5A2.

Omic studies reveal the pathogenic lipid droplet proteins in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is an epidemic metabolic condition driven by an underlying lipid homeostasis disorder. The lipid droplet (LD), the main organelle involved in neutral lipid storage and hydrolysis, is a potential target for NAFLD therapeutic treatment. In this review, we summarize recent progress elucidating the connections between LD-associated proteins and NAFLD found by genome-wide association studies (GWAS), genomic and proteomic studies. Finally, we discuss a possible mechanism by which the protein 17β-hydroxysteroid dehydrogenase 13 (17β-HSD13) may promote the development of NAFLD.

Intracrine Control of Estrogen Action in Human Gestational Tissues at Parturition

OBJECTIVE

We examined whether estrogen action in human parturition is regulated by an intracrine mechanism mediated by target tissue expression of specific 17beta-hydroxysteroid dehydrogenase (17betaHSD) isozymes that interconvert estrone (E1) and estradiol (E2), such that the onset of labor is associated with an increase in local E2 bioavailability.

METHODS

The extent of 17betaHSD-1, -2, -3, -4, -5, and -7 expression (measured by quantitative reverse transcriptase polymerase chain reaction) and the capacity to interconvert E1 and E2 were compared in amnion, chorion, placenta, decidua, and myometrium obtained from women at term before (n = 6) and after (n = 6) the onset of labor.

RESULTS

In chorion, abundance of 17betaHSD-1 (converts E1 to E2) mRNA decreased 2.7-fold (P <.05) in association with labor onset. In myometrium, 17betaHSD-1 and 17betaHSD-4 (converts E2 to E1) mRNAs increased two-fold and five-fold, respectively, with the onset of labor (P <.05 for each). No other statistically significant labor-associated change in 17betaHSD expression was observed. In chorion, 17betaHSD oxidative (E2 to E1) and reductive (E1 to E2) activities and the net E2 synthetic capacity increased with labor. In decidua, both activities decreased with the onset of labor, but there was no change in net E2 synthetic capacity. The capacity to interconvert E1 and E2 did not change in the other tissues.

CONCLUSION

The increase in E2 synthetic capacity in the chorion might contribute to an increase in local estrogen bioactivity in association with the onset of labor. However, it cannot be explained by changes in 17betaHSD isozyme expression and is unlikely to account for the increased estrogen action at parturition. These data show that intracrine mechanisms based on 17betaHSD isozyme expression play a minor role, if any, in controlling estrogen action in gestational tissues during human parturition.

Mimicking postmenopausal steroid metabolism in breast cancer cell culture: Differences in response to DHEA or other steroids as hormone sources

Following menopause virtually 100% of estrogens are synthesized in peripheral target tissues from precursor steroids of adrenal origin. These steroids are the unique source of sex steroids in these women. This positions some steroid metabolizing enzymes as primary targets for novel therapies for estrogen receptor-positive (ER+) breast cancer. However, previous research on the steroid-converting enzymes has been performed using their direct substrate as a hormone source, depending on the facility where studied and the robust signal obtained. These experiments may not always provide an accurate reflection of physiological and post-menopausal conditions. We suggest providing dehydroepiandrosterone (DHEA) as an intracrinological hormone source, and comparing the role of steroid-converting enzymes using DHEA and their direct substrates when an extensive mechanistic understanding is required. Here, we present a comparative study of these enzymes with the provision of DHEA and the direct substrates, estrone (E1) or dihydrotestosterone (DHT), or additional steroids as hormone sources, in breast cancer cells. Enzyme knockdown by respective specific siRNAs and observations on the resulting differences in biological function were carried out. Cell biology studies showed no difference in biological function for 17β-HSD1 and 17β-HSD7 when cultured with different steroid hormones: cell proliferation and estradiol levels decreased, whereas DHT accumulated; cyclinD1, PCNA, and pS2 were down-regulated after knocking down these two enzymes, although the quantitative results varied. However, culture medium supplementation was found to have a marked impact on the study of 3α-HSD3. We demonstrated that provision of different steroids as a substrate or hormone sources may promote modified biological effects: provision of DHEA is the preferred choice to mimic postmenopausal steroid metabolism in cell culture.

Androgen-metabolizing enzymes: A structural perspective

Androgen-metabolizing enzymes convert cholesterol, a relatively inert molecule, into some of the most potent chemical messengers in vertebrates. This conversion involves thermodynamically challenging reactions catalyzed by P450 enzymes and redox reactions catalyzed by Aldo-Keto Reductases (AKRs). This review covers the structures of these enzymes with a focus on active site interactions and proposed mechanisms. Due to their role in a number of diseases, particularly in cancer, androgen-metabolizing enzymes have been targets of drug design. Hence we will also highlight how existing knowledge of structure is being used to this end.

Cervical Length and Androgens in Pregnant Women With Polycystic Ovary Syndrome: Has Metformin Any Effect?

CONTEXT

Women with polycystic ovary syndrome (PCOS) have increased risk of preterm delivery. Shortening of the cervix is a sign of preterm delivery.

OBJECTIVE

This study aimed to investigate potential effect of metformin on cervical length and whether androgen levels correlate with cervical length in PCOS pregnancies.

DESIGN AND SETTING

This was a sub-study of a randomized, placebo-controlled, multicenter study (The PregMet study) performed at 11 secondary or tertiary centers from 2005 to 2009.

PARTICIPANTS

Two-hundred sixty-one pregnancies of 245 women with PCOS, age 18-42 years participated.

INTERVENTIONS

Participants were randomly assigned to metformin or placebo from first trimester to delivery.

OUTCOME MEASUREMENTS

We compared cervical length and androgen levels in metformin and placebo groups at gestational weeks 19 and 32. We also explored whether cervical length correlated with androgen levels.

RESULTS

We found no difference in cervical length between the metformin and the placebo groups at gestational week 19 and 32. Dehydroepiandrosterone (DHEAS) tended to be higher in the metformin group. There were no correlations between androgens and cervical length at week 19. At gestational week 32, androstenedione (P = .02) and DHEAS (P = .03) showed a trend toward negative correlation to cervical length. High androstenedione level correlated with shortening of cervical length from week 19 to 32 when adjusted for confounders (P = .003). T (P = .03), DHEAS (P = .02), and free testosterone index (P = .03) showed a similar trend.

CONCLUSION

Metformin in pregnancy did not affect cervical length in women with PCOS. High maternal androgen levels correlated with cervical shortening from the second to the third trimester of pregnancy, as a sign of cervical ripening.

Current knowledge of the multifunctional 17β-hydroxysteroid dehydrogenase type 1 (HSD17B1)

At the late 1940s, 17β-HSD1 was discovered as the first member of the 17β-HSD family with its gene cloned. The three-dimensional structure of human 17β-HSD1 is the first example of any human steroid converting enzyme. The human enzyme's structure and biological function have thus been studied extensively in the last two decades. In humans, the enzyme is expressed in placenta, ovary, endometrium and breast. The high activity of estrogen activation provides the basis of 17β-HSD1's implication in estrogen-dependent diseases, such as breast cancer, endometriosis and non-small cell lung carcinomas. Its dual function in estrogen activation and androgen inactivation has been revealed in molecular and breast cancer cell levels, significantly stimulating the proliferation of such cells. The enzyme's overexpression in breast cancer was demonstrated by clinical samples. Inhibition of human 17β-HSD1 led to xenograft tumor shrinkage. Unfortunately, through decades of studies, there is still no drug using the enzyme's inhibitors available. This is due to the difficulty to get rid of the estrogenic activity of its inhibitors, which are mostly estrogen analogues. New non-steroid inhibitors for the enzyme provide new hope for non-estrogenic inhibitors of the enzyme.

The Metabolism, Analysis, and Targeting of Steroid Hormones in Breast and Prostate Cancer

Breast and prostate cancers are malignancies in which steroid hormones drive cellular proliferation. Over the past century, this understanding has led to successful treatment strategies aimed to inhibit hormone-mediated tumor growth. Nonetheless, disease relapse and progression still pose significant clinical problems, with recurrent and metastatic tumors often exhibiting resistance to current drug therapies. The central role of androgens and estrogens in prostate and breast cancer etiology explains not only why endocrine therapies are often initially successful but also why many tumors ultimately become resistant. It is hypothesized that reducing the concentration of active hormones in the systemic circulation may be insufficient to block cancer progression, as this action selects for tumor cells that can generate active steroids from circulating precursors. This review aims to highlight the currently known differences of steroid biosynthesis in normal physiology versus hormone-dependent cancers, modern approaches to the assessment and targeting of these pathways, and priorities for future research.

CYP24 inhibition as a therapeutic target in FGF23-mediated renal phosphate wasting disorders

CYP24A1 (hereafter referred to as CYP24) enzymatic activity is pivotal in the inactivation of vitamin D metabolites. Basal renal and extrarenal CYP24 is usually low but is highly induced by its substrate 1,25-dihydroxyvitamin D. Unbalanced high and/or long-lasting CYP24 expression has been proposed to underlie diseases like chronic kidney disease, cancers, and psoriasis that otherwise should favorably respond to supplemental vitamin D. Using genetically modified mice, we have shown that renal phosphate wasting hypophosphatemic states arising from high levels of fibroblast growth factor 23 (FGF23) are also associated with increased renal Cyp24 expression, suggesting that elevated CYP24 activity is pivotal to the pathophysiology of these disorders. We therefore crossed 2 mouse strains, each with distinct etiology for high levels of circulating FGF23, onto a Cyp24-null background. Specifically, we evaluated Cyp24 deficiency in Hyp mice, the murine homolog of X-linked dominant hypophosphatemic rickets, and transgenic mice that overexpress a mutant FGF23 (FGF23R176Q) that is associated with the autosomal dominant form of hypophosphatemic rickets. Loss of Cyp24 in these murine models of human disease resulted in near-complete recovery of rachitic/osteomalacic bony abnormalities in the absence of any improvement in the serum biochemical profile. Moreover, treatment of Hyp and FGF23R1760-transgenic mice with the CYP24 inhibitor CTA102 also ameliorated their rachitic bones. Our results link CYP24 activity to the pathophysiology of FGF23-dependent renal phosphate wasting states and implicate pharmacologic CYP24 inhibition as a therapeutic adjunct for their treatment.

Transcript level of AKR1C3 is down-regulated in gastric cancer

Steroid hormones have been shown to play a role in gastric carcinogenesis. Large amounts of steroid hormones are locally produced in the peripheral tissues of both genders. Type 5 of 17β-hydroxysteroid dehydrogenase, encoded by the AKR1C3 gene, plays a pivotal role in both androgen and estrogen metabolism, and its expression was found to be deregulated in different cancers. In this study we measured AKR1C3 transcript and protein levels in nontumoral and primary tumoral gastric tissues, and evaluated their association with some clinicopathological features of gastric cancer (GC). We found decreased levels of AKR1C3 transcript (p < 0.0001) and protein (p = 0.0021) in GC tissues compared with the adjacent, apparently histopathologically normal, mucosa. Lower levels of AKR1C3 transcript were observed in diffuse and intestinal types of GC, whereas AKR1C3 protein levels were decreased in tumors with multisite localization, in diffuse histological type, T3, T4, and G3 grades. We also determined the effect of the histone deacetylase inhibitor sodium butyrate (NaBu) on AKR1C3 expression in EPG 85-257 and HGC-27 GC cell lines. We found that NaBu elevates the levels of both AKR1C3 transcript and protein in the cell lines we investigated. Together, our results suggest that decreased expression of AKR1C3 may be involved in development of GC and can be restored by NaBu.

Cytochrome P450 17A1 inhibitor abiraterone attenuates cellular growth of prostate cancer cells independently from androgen receptor signaling by modulation of oncogenic and apoptotic pathways

Abiraterone provides significant survival advantages in prostate cancer (PC), however, the current understanding of the molecular mechanisms of abiraterone is still limited. Therefore, the abiraterone impact on androgen receptor (AR)-positive LNCaP and AR-negative PC-3 cells was assessed by cellular and molecular analyses. The present study demonstrated, that abiraterone treatment significantly decreased cell growth, AR expression, and AR activity of AR-positive LNCaP cells. Notably, AR-negative PC-3 cells exhibited comparable reductions in cellular proliferation, associated with DNA fragmentation and pro-apoptotic modulation of p21, caspase-3, survivin, and transforming growth factor β (TGFβ). Our observations suggest that the attenuation of AR signaling is not the only rationale to explain the abiraterone anticancer activity. Abiraterone efficacy may play a more global role in PC progression control than originally hypothesized. In this regard, abiraterone is not only a promising drug for treatment of AR-negative PC stages, even more, abiraterone may represent an alternative for treatment of other malignancies besides prostate cancer.

In vitro interactions between mammary fibroblasts (Hs 578Bst) and cancer epithelial cells (MCF-7) modulate aromatase, steroid sulfatase and 17β-hydroxysteroid dehydrogenases

Our objectives were to investigate the interactions between mammary cancer epithelial cells (MCF-7) and stromal cells (Hs-578Bst) at the level of the expression and inhibition of steroidogenesis enzymes by using monolayer and three dimensional co-culture models. Expressions of steroidogenesis enzymes and E2/DHT conversions in co-cultured MCF-7 and Hs-578Bst cells as well as the effects of aromatase inhibitor combined to steroid sulfatase (STS) and 17β-hydroxysteroid dehydrogenases (17βHSDs) inhibitors were evaluated. 17β-HSD type 7 was mostly modulated in MCF-7 cells whereas aromatase was mostly regulated in Hs578Bst cells thereby increasing E2 conversion and MCF-7 cell growth. A combination of inhibitors toward aromatase, STS and 17β-HSD7, was found to be the most significant treatment in decreasing E2 and elevating DHT thus inhibiting MCF-7 cell proliferation and spheroid-like cancer cell aggregation in collagen gel. The interactions between those cells modulated E2 formation in paracrine/intracrine manners by synergistically regulating aromatase, 17β-HSD7 and STS. Among tumor-associated cells, stromal fibroblasts may participate in intratumoral E2 deposition; therefore promoting breast cancer cell growth.

Steroidogenic enzyme profile in an androgen-secreting adrenocortical oncocytoma associated with hirsustism

Hirsutism induced by hyperandrogenism can be associated with polycystic ovary syndrome, 21-hydroxylase (OH) deficiency or androgen-secreting tumors, including ovarian and adrenal tumors. Adrenal androgen-secreting tumors are frequently malignant. Adrenal oncocytomas represent rare causes of hyperandrogenism. The aim of the study was to investigate steroidogenic enzyme expression and steroid secretion in an androgen-secreting adrenal oncocytoma in a young woman presenting with hirsutism. Hyperandrogenism was diagnosed on the basis of elevated plasma Δ4-androstenedione and testosterone levels. Pelvic ultrasound was normal, CT scanning revealed a right adrenal mass. Androgens were assessed in adrenal and ovarian vein samples and proved a right adrenal origin. Adrenalectomy normalized androgen levels and the adrenal tumor was diagnosed as an oncocytoma. Real time-PCR, immunohistochemistry and cell culture studies were performed on tumor explants to investigate the steroid secretion profile. Among enzymes required for cortisol synthesis, 17α-OH and 3β-hydroxysteroid dehydrogenase 2 (3β-HSD2) were highly expressed whereas 21-OH and 11β-OH were weakly produced at the mRNA and/or protein levels. Enzymes involved in testosterone production, 17β-HSD5 and 17β-HSD3, were also detected. ACTH receptor was present in the tissue. Cortisol, Δ4-androstenedione and testosterone secretions by cultured cells were increased by ACTH. These results provide the first demonstration, to our knowledge, of abnormal expression profile of steroidogenic enzymes in an adrenocortical oncocytoma. Our results also indicate that Δ4-androstenedione hypersecretion resulted from high 17α-OH and 3β-HSD2 expression in combination with low expression of 21-OH and 11β-OH. Testosterone production was ascribed to occurrence of 17β-HSD5 and 17β-HSD3. Finally, our results indicate that androgen secretion was stimulated by ACTH.

Neural transcriptome reveals molecular mechanisms for temporal control of vocalization across multiple timescales

Background

Vocalization is a prominent social behavior among vertebrates, including in the midshipman fish, an established model for elucidating the neural basis of acoustic communication. Courtship vocalizations produced by territorial males are essential for reproductive success, vary over daily and seasonal cycles, and last up to hours per call. Vocalizations rely upon extreme synchrony and millisecond precision in the firing of a homogeneous population of motoneurons, the vocal motor nucleus (VMN). Although studies have identified neural mechanisms driving rapid, precise, and stable neuronal firing over long periods of calling, little is known about underlying genetic/molecular mechanisms.

Results

We used RNA sequencing-based transcriptome analyses to compare patterns of gene expression in VMN to the surrounding hindbrain across three daily and seasonal time points of high and low sound production to identify candidate genes that underlie VMN’s intrinsic and network neuronal properties. Results from gene ontology enrichment, enzyme pathway mapping, and gene category-wide expression levels highlighted the importance of cellular respiration in VMN function, consistent with the high energetic demands of sustained vocal behavior. Functionally important candidate genes upregulated in the VMN, including at time points corresponding to high natural vocal activity, encode ion channels and neurotransmitter receptors, hormone receptors and biosynthetic enzymes, neuromodulators, aerobic respiration enzymes, and antioxidants. Quantitative PCR and RNA-seq expression levels for 28 genes were significantly correlated. Many candidate gene products regulate mechanisms of neuronal excitability, including those previously identified in VMN motoneurons, as well as novel ones that remain to be investigated. Supporting evidence from previous studies in midshipman strongly validate the value of transcriptomic analyses for linking genes to neural characters that drive behavior.

Conclusions

Transcriptome analyses highlighted a suite of molecular mechanisms that regulate vocalization over behaviorally relevant timescales, spanning milliseconds to hours and seasons. To our knowledge, this is the first comprehensive characterization of gene expression in a dedicated vocal motor nucleus. Candidate genes identified here may belong to a conserved genetic toolkit for vocal motoneurons facing similar energetic and neurophysiological demands.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1577-2) contains supplementary material, which is available to authorized users.

C21-steroids inactivation and glucocorticoid synthesis in the developing lung

Glucocorticoids (GCs) are important regulators of lung development. The genes normally involved in GC synthesis in adrenals are co-expressed with 20α-hydroxysteroid dehydrogenase (20α-HSD) in the developing lung. In this study, C21-steroid metabolism was investigated in fetal and postnatal mouse lungs. Incubation of [(3)H]-progesterone with lung explant cultures of different perinatal developmental time points revealed two different (antenatal vs. postnatal) complex metabolization patterns. Progesterone inactivation was predominant. 20αOH-derivatives were more abundant after birth and some metabolites were 5α-reduced. Using [(3)H]-progesterone as substrate, corticosterone synthesis was only observed in a fraction of lung explants from gestation day (GD) 15.5. Neither aldosterone synthase nor P450c17 activity was observed. With epithelial-enriched primary cell cultures, deoxycorticosterone synthesis from [(3)H]-progesterone was observed. With lung explants incubated with [(3)H]-corticosterone as substrate, [(3)H]-4-pregnen-21-ol-3,11,20-trione (11-dehydrocorticosterone), the product of 11β-HSD2, accumulated in higher proportion on GD 15.5 than at later developmental time points. The temporal correlation observed between levels of progesterone inactivation by 20α-HSD (higher after birth) and the sensitivity of lung development to GCs suggests a role for 20α-HSD in the modulation of GR occupancy through the control of 21-hydroxylase substrate and product levels. In conclusion, the developing lung is characterized by effective inactivation of c21-steroids by 20α-HSD. The formation of active GCs from the "adrenal"-like pathway was observed with some lung explants and primary epithelial cell cultures. Coexistence of this GC synthesis pathway with 20α-HSD activity strongly suggests local regulation of GC action and is compatible with intracrine/paracrine actions of GC.

The intracrinology of breast cancer

The importance of intracrinology, or in situ production of steroids from circulating precursors, in breast cancer has been firmly established in estrogen actions on postmenopausal patients. Expression levels of various steroid synthesizing and/or metabolizing enzymes have been examined in human breast cancer tissues by a number of groups. The enzymes examined include those capable of converting circulating DHEA-S to sex steroids (STS and 3βHSDΔ4-5 isomerase), the group of enzymes that modulate the strength of both androgens and estrogens (17βHSD family) as well as the androgenic 5αR enzymes and the estrogenic aromatase enzyme. In addition to these DHEA-related metabolism pathways, other intracrine pathways involving progesterone and cholesterol have also been examined. Some risk factors of breast cancer development, including obesity, have also been postulated to interact with steroid metabolising pathways. In this review, we aimed to summarise the current state of knowledge regarding intracrine metabolism including expression levels of various enzymes and receptors, focusing particularly upon the importance of the production of biologically potent steroids from circulating sulfated precursors such as DHEA-S. In addition, we attempted to summarise the factors, both steroidal and non-steroidal, involved in the regulation of these enzymes and propose future directions for research in this particular field. The concept of intracrinology was first proposed over 20 years ago but there still remain many unanswered questions which could open new horizons for the understanding of intracrine metabolism in the breast. This article is part of a Special Issue entitled 'Essential role of DHEA'.

Combined blockade of testicular and locally made androgens in prostate cancer: a highly significant medical progress based upon intracrinology

Recently two drugs, namely the antiandrogen MDV-3100 and the inhibitor of 17α-hydroxylase abiraterone have been accepted by the FDA for the treatment of castration-resistant prostate cancer (CRPC) with or without previous chemotherapy, with a prolongation of overall survival of 2.2-4.8 months. While medical (GnRH agonist) or surgical castration reduces the serum levels of testosterone by about 97%, an important concentration of testosterone and dihydrotestosterone remains in the prostate and activates the androgen receptor (AR), thus offering an explanation for the positive data obtained in CRPC. In fact, explanation of the response observed with MDV-3100 or enzalutamide in CRPC is essentially a blockade of the action or formation of intraprostatic androgens. In addition to the inhibition of the action or formation of androgens made locally by the mechanisms of intracrinology, increased AR levels and AR mutations can be involved, especially in very advanced disease. Future developments look at more efficient inhibitors of the action or formation of intraprostatic androgens and starting treatment earlier when blockade of androgens can exert long-term control and even cure prostate cancer treated at a stage before the appearance of metastases. This article is part of a Special Issue entitled 'Essential role of DHEA'.

Expression of the estrogen receptors and steroidogenic enzymes involved in estradiol formation in the monkey vagina

OBJECTIVE

Estrogens are well recognized to have beneficial effects on vulvovaginal atrophy because of menopause. The distribution of estrogen receptors and enzymes responsible for estradiol (E2) formation within the vagina may provide insight into how dehydroepiandrosterone, a precursor of both estrogens and androgens, improves vulvovaginal atrophy.

STUDY DESIGN

The purpose of the study was to determine where the steroidogenic enzymes responsible for E2 formation as well as estrogen receptors are localized in vaginal specimens collected from cynomolgus monkeys (Macaca fascicularis), the closest model to the human. HSD3B1, HSD17B1, HSD17B5, HSD17B12, aromatase (CYP19A1), estrogen receptor (ER)-α, and ER-β were measured or localized by quantitative real-time polymerase chain reaction, immunohistochemistry, and immunofluorescence. Estrogens were quantified by liquid chromatography/tandem mass spectrometry.

RESULTS

All steroidogenic enzymes and estrogen receptors are localized mainly in the superficial layer of the stratified squamous epithelium, blood vessel walls, and muscle fibers of the vagina. Immunolabeling of HSD17B5 and HSD17B12 shows that these enzymes are uniformly distributed from the basal membrane to the superficial keratinized cells, whereas HSD3B1 and aromatase are particularly localized in the outer (external) portion of the epithelial layer. ER-α and ER-β are also distributed within the vaginal epithelium, with expression especially elevated at the basal membrane level.

CONCLUSION

The enzymes responsible for E2 formation as well as ERs are expressed mainly in the superficial layer of the stratified epithelium as well as the muscle layer of the vagina. The present data provide morphologic and biochemical support for the role of local dehydroepiandrosterone transformation into estrogens in regulating epithelial cell maturation, pH, fluid secretion, smooth muscle activity, and blood flow regulation in the primate vagina.

Expression of steroidogenic enzymes in human sebaceous glands

Androgens are well known to influence sebum synthesis and secretion. Various factors related to androgen biosynthesis are expressed in human sebaceous glands. In this study, immunohistochemical analysis of human skin specimens from 43 subjects indicated that various androgen-producing and -metabolizing enzymes were functionally localized to sebocytes accumulating lipid droplets and that the exclusive expression of 17β-hydroxysteroid dehydrogenase type 2 (17β-HSD2 (HSD17B2)) in sebaceous glands was negatively correlated with that of peroxisome proliferator-activated receptor gamma (PPARγ (PPARG)), which also significantly changed in an age-dependent manner. We also demonstrated that the changes of 17β-HSD2 expression in human immortalized sebocytes (SZ95) influenced the expressions of sebogenesis-related factors. In addition, the overexpression of 17β-HSD2 in SZ95 significantly increased the androstenedione production and markedly decreased the amounts of testosterone and dihydrotestosterone when DHEA was added externally. On the other hand, the phosphorylation of mammalian target of rapamycin, which is well known to induce sebum secretion and the onset and/or aggravation of acne, was increased by the addition of testosterone in the presence of IGF1 in hamster sebocytes. These results all indicated that local androgen biosynthesis and metabolism in human sebaceous glands could play a pivotal role in sebum synthesis and secretion.

Beyond T and DHT - novel steroid derivatives capable of wild type androgen receptor activation

While androgen deprivation therapy (ADT) remains the primary treatment for metastatic prostate cancer (PCa), castration does not eliminate androgens from the prostate tumor microenvironment, and residual intratumoral androgens are implicated in nearly every mechanism by which androgen receptor (AR)-mediated signaling promotes castration-resistant disease. The uptake and intratumoral (intracrine) conversion of circulating adrenal androgens such as dehydroepiandrosterone sulfate (DHEA-S) to steroids capable of activating the wild type AR is a recognized driver of castration resistant prostate cancer (CRPC). However, less well-characterized adrenal steroids, including 11-deoxcorticosterone (DOC) and 11beta-hydroxyandrostenedione (11OH-AED) may also play a previously unrecognized role in promoting AR activation. In particular, recent data demonstrate that the 5α-reduced metabolites of DOC and 11OH-AED are activators of the wild type AR. Given the well-recognized presence of SRD5A activity in CRPC tissue, these observations suggest that in the low androgen environment of CRPC, alternative sources of 5α-reduced ligands may supplement AR activation normally mediated by the canonical 5α-reduced agonist, 5α-DHT. Herein we review the emerging data that suggests a role for these alternative steroids of adrenal origin in activating the AR, and discuss the enzymatic pathways and novel downstream metabolites mediating these effects. We conclude by discussing the potential implications of these findings for CRPC progression, particularly in context of new agents such as abiraterone and enzalutamide which target the AR-axis for prostate cancer therapy.

Immunoexpression of aromatase cytochrome P450 and 17β-hydroxysteroid dehydrogenase in women's ovaries after menopause

Background

Menopause results in a lack of regular menstrual cycles, leading to the reduction of estrogen production. On the other hand, ovarian androgen synthesis is still present at reduced levels and requires expression of several steroidogenic enzymes.

Methods

This study was performed on 104 postmenopausal women hospitalized due to uterine leiomyomas, endometriosis, and/or a prolapsed uterus. Patients were divided into three groups depending on the time from menopause. Group A patients experienced menopause 1–5 years before enrollment in the study (42 women). Group B included women who had their last menstruation 5–10 years before the study (40 women). Group C consisted of 22 women who were more than 10 years past menopause. Hysterectomy or removal of the uterine corpus with adnexa was performed during laparotomy. We evaluated the expression of aromatase cytochrome P450 (CYP 19) and 17β-hydroxysteroid dehydrogenase (17β HSD) by employing immunohistochemistry.

Results

Activity of 17β-HSD and CYP19 was demonstrated in the cytoplasm of stromal cells of postmenopausal ovaries, epithelium cells coating the ovaries, vascular endothelial cells, and epithelial inclusion cysts. However, overall expression of both 17β-HSD and CYP 19 decreased with time after menopause.

Conclusion

Demonstration of the activity of the key enzymes of ovarian steroidogenesis, CYP 19 and 17β-HSD, confirms steroidogenic activity in the ovaries of postmenopausal women. Nevertheless, ovarian steroidogenic activity decreases with time, and its significant decrease occurs 10 years after menopause.

Concurrent estrogen action was essential for maximal progestin effect in oral contraceptives

OBJECTIVE

To investigate the impact of estrogen contained in oral contraceptives (OCs) on the action of progestin on ovarian endometrioma epithelial cells.

DESIGN

Experimental in vitro study and immunohistochemical analysis.

SETTING

University hospital.

PATIENT(S)

Patients who underwent surgery due to ovarian endometrioma.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Telomerase-immortalized epithelial cells derived from ovarian endometrioma were treated with norethindorone (NET; 80 nmol/L) or levonorgestrel (LNG; 20 nmol/L) with or without 17β-ethynylestradiol (EE; 0.6 nmol/L) for 96 hours, and the cell growth was monitored. Estrogen receptor (ER) α, progesterone receptor (PR) A, and PRB expressions in clinical samples of ovarian endometrioma epithelial cells were analyzed with the use of immunohistochemistry.

RESULT(S)

NET or LNG effectively suppressed cell growth, and addition of EE significantly enhanced the growth suppression. This EE-mediated enhancement of cell growth suppression was observed only in cells that expressed ERα and therefore was ERα dependent. Western blot analysis revealed that expression of PRB was significantly induced by the addition of EE. Immunohistochemical analysis confirmed that ERα expression and PRB expression are significantly correlated, indicating that progestin-sensitive cells with PRB expression are predisposed to react with estrogen stimulation.

CONCLUSION(S)

These findings suggest that EE contained in OCs plays a supportive role in progestin-induced growth inhibition of ovarian endometrioma epithelial cells. In the absence of estrogen priming, concurrent estrogen action was essential for rapid induction of PR to achieve maximal progestin effect.