Mechanisms of androgen receptor activation and function

Maternal social environment shapes yolk testosterone allocation and embryonic neural gene expression in tree swallows

Offspring from females breeding in competitive social environments are often exposed to more testosterone (T) during embryonic development, which can affect traits from growth to behavior in potentially adaptive ways. Despite the important role of maternally derived steroids in shaping offspring development, the molecular mechanisms driving these processes are currently unclear. Here, we use tree swallows (Tachycineta bicolor) to explore the effects of the maternal social environment on yolk T concentrations and genome-wide patterns of neural gene expression in embryos. We measured aggressive interactions among females breeding at variable densities and collected their eggs at two timepoints, including the day laid to measure yolk T concentrations and on embryonic day 11 to measure gene expression in whole brain samples. We found that females breeding in high-density sites experienced elevated rates of physical aggression and their eggs had higher yolk T concentrations. A differential gene expression and weighted gene co-expression network analysis indicated that embryos from high-density sites experienced an upregulation of genes involved in hormone, circulatory, and immune processes, and these gene expression patterns were correlated with yolk T levels and aggression. Genes implicated in neural development were additionally downregulated in embryos from high-density sites. These data highlight how early neurogenomic processes may be affected by the maternal social environment, giving rise to phenotypic plasticity in offspring.

Systematic review and integrated analysis of prognostic gene signatures for prostate cancer patients

Prostate cancer (PC) is one of the most common cancers in men and becoming the second leading cause of cancer fatalities. At present, the lack of effective strategies for prognosis of PC patients is still a problem to be solved. Therefore, it is significant to identify potential gene signatures for PC patients' prognosis. Here, we summarized 71 different prognostic gene signatures for PC and concluded 3 strategies for signature construction after extensive investigation. In addition, 14 genes frequently appeared in 71 different gene signatures, which enriched in mitotic and cell cycle. This review provides extensive understanding and integrated analysis of current prognostic signatures of PC, which may help researchers to construct gene signatures of PC and guide future clinical treatment.

PAXIP1 and STAG2 converge to maintain 3D genome architecture and facilitate promoter/enhancer contacts to enable stress hormone-dependent transcription

How steroid hormone receptors (SHRs) regulate transcriptional activity remains partly understood. Upon activation, SHRs bind the genome together with a co-regulator repertoire, crucial to induce gene expression. However, it remains unknown which components of the SHR-recruited co-regulator complex are essential to drive transcription following hormonal stimuli. Through a FACS-based genome-wide CRISPR screen, we functionally dissected the Glucocorticoid Receptor (GR) complex. We describe a functional cross-talk between PAXIP1 and the cohesin subunit STAG2, critical for regulation of gene expression by GR. Without altering the GR cistrome, PAXIP1 and STAG2 depletion alter the GR transcriptome, by impairing the recruitment of 3D-genome organization proteins to the GR complex. Importantly, we demonstrate that PAXIP1 is required for stability of cohesin on chromatin, its localization to GR-occupied sites, and maintenance of enhancer-promoter interactions. In lung cancer, where GR acts as tumor suppressor, PAXIP1/STAG2 loss enhances GR-mediated tumor suppressor activity by modifying local chromatin interactions. All together, we introduce PAXIP1 and STAG2 as novel co-regulators of GR, required to maintain 3D-genome architecture and drive the GR transcriptional programme following hormonal stimuli.

Weight of evidence for cross-species conservation of androgen receptor-based biological activity

The U.S. Environmental Protection Agency's Endocrine Disruptor Screening Program (EDSP) is tasked with assessing chemicals for their potential to perturb endocrine pathways, including those controlled by androgen receptor (AR). To address challenges associated with traditional testing strategies, EDSP is considering in vitro high-throughput screening assays to screen and prioritize chemicals more efficiently. The ability of these assays to accurately reflect chemical interactions in nonmammalian species remains uncertain. Therefore, a goal of the EDSP is to evaluate how broadly results can be extrapolated across taxa. To assess the cross-species conservation of AR-modulated pathways, computational analyses and systematic literature review approaches were used to conduct a comprehensive analysis of existing in silico, in vitro, and in vivo data. First, molecular target conservation was assessed across 585 diverse species based on the structural similarity of ARs. These results indicate that ARs are conserved across vertebrates and are predicted to share similarly susceptibility to chemicals that interact with the human AR. Systematic analysis of over 5000 published manuscripts was used to compile in vitro and in vivo cross-species toxicity data. Assessment of in vitro data indicates conservation of responses occurs across vertebrate ARs, with potential differences in sensitivity. Similarly, in vivo data indicate strong conservation of the AR signaling pathways across vertebrate species, although sensitivity may vary. Overall, this study demonstrates a framework for utilizing bioinformatics and existing data to build weight of evidence for cross-species extrapolation and provides a technical basis for extrapolating hAR-based data to prioritize hazard in nonmammalian vertebrate species.

Androgenic induction of penile features in postnatal female mouse external genitalia from birth to adulthood: Is the female sexual phenotype ever irreversibly determined?

Female mice were treated for 35 days from birth to 60 days postnatal (P0, [birth], P5, P10, P20 and adult [∼P60]) with dihydrotestosterone (DHT). Such treatment elicited profound masculinization the female external genitalia and development of penile features (penile spines, male urogenital mating protuberance (MUMP) cartilage, corpus cavernosum glandis, corporal body, MUMP-corpora cavernosa, a large preputial space, internal preputial space, os penis). Time course studies demonstrated that DHT elicited canalization of the U-shaped clitoral lamina to create a U-shaped preputial space, preputial lining epithelium and penile epithelium adorned with spines. The effect of DHT was likely due to signaling through androgen receptors normally present postnatally in the clitoral lamina and associated mesenchyme. This study highlights a remarkable male/female difference in specification and determination of urogenital organ identity. Urogenital organ identity in male mice is irreversibly specified and determined prenatally (prostate, penis, and seminal vesicle), whereas many aspects of the female urogenital organogenesis are not irreversibly determined at birth and in the case of external genitalia are not irreversibly determined even into adulthood, the exception being positioning of the female urethra, which is determined prenatally.

Extensive Variation in Gene Expression is Revealed in 13 Fertility-Related Genes Using RNA-Seq, ISO-Seq, and CAGE-Seq From Brahman Cattle

Fertility is a key driver of economic profitability in cattle production. A number of studies have identified genes associated with fertility using genome wide association studies and differential gene expression analysis; however, the genes themselves are poorly characterized in cattle. Here, we selected 13 genes from the literature which have previously been shown to have strong evidence for an association with fertility in Brahman cattle (Bos taurus indicus) or closely related breeds. We examine the expression variation of the 13 genes that are associated with cattle fertility using RNA-seq, CAGE-seq, and ISO-seq data from 11 different tissue samples from an adult Brahman cow and a Brahman fetus. Tissues examined include blood, liver, lung, kidney, muscle, spleen, ovary, and uterus from the cow and liver and lung from the fetus. The analysis revealed several novel isoforms, including seven from SERPINA7. The use of three expression characterization methodologies (5′ cap selected ISO-seq, CAGE-seq, and RNA-seq) allowed the identification of isoforms that varied in their length of 5′ and 3′ untranslated regions, variation otherwise undetectable (collapsed as degraded RNA) in generic isoform identification pipelines. The combinations of different sequencing technologies allowed us to overcome the limitations of relatively low sequence depth in the ISO-seq data. The lower sequence depth of the ISO-seq data was also reflected in the lack of observed expression of some genes that were observed in the CAGE-seq and RNA-seq data from the same tissue. We identified allele specific expression that was tissue-specific in AR, IGF1, SOX9, STAT3, and TAF9B. Finally, we characterized an exon of TAF9B as partially nested within the neighboring gene phosphoglycerate kinase 1. As this study only examined two animals, even more transcriptional variation may be present in a genetically diverse population. This analysis reveals the large amount of transcriptional variation within mammalian fertility genes and illuminates the fact that the transcriptional landscape cannot be fully characterized using a single technology alone.

Androgen receptor-mediated transcriptional repression targets cell plasticity in prostate cancer

Androgen receptor (AR) signaling remains the key therapeutic target in the management of hormone‐naïve‐advanced prostate cancer (PCa) and castration‐resistant PCa (CRPC). Recently, landmark molecular features have been reported for CRPC, including the expression of constitutively active AR variants that lack the ligand‐binding domain. Besides their role in CRPC, AR variants lead to the expression of genes involved in tumor progression. However, little is known about the specificity of their mode of action compared with that of wild‐type AR (AR‐WT). We performed AR transcriptome analyses in an androgen‐dependent PCa cell line as well as cross‐analyses with publicly available RNA‐seq datasets and established that transcriptional repression capacity that was marked for AR‐WT was pathologically lost by AR variants. Functional enrichment analyses allowed us to associate AR‐WT repressive function to a panel of genes involved in cell adhesion and epithelial‐to‐mesenchymal transition. So, we postulate that a less documented AR‐WT normal function in prostate epithelial cells could be the repression of a panel of genes linked to cell plasticity and that this repressive function could be pathologically abrogated by AR variants in PCa.

The Metastasis Suppressor NDRG1 Directly Regulates Androgen Receptor Signaling in Prostate Cancer

N-myc-downregulated gene 1 (NDRG1) has potent anticancer effects and inhibits cell growth, survival, metastasis, and angiogenesis. Previous studies suggested that NDRG1 is linked to the androgen signaling network, but this mechanistic relationship is unclear. Considering the crucial role of the androgen receptor (AR) in prostate cancer (PCa) progression, here we examined for the first time the effect of NDRG1 on AR expression, activation, and downstream signaling in LNCaP, 22Rv1, and C4-2B PCa cell types. We demonstrate that NDRG1 effectively promotes interaction of AR with the chaperone HSP90, which in turn stabilizes the AR while decreasing its androgen-mediated activation. The expression of NDRG1 suppressed: (1) AR activation, as measured by p-AR^Ser213 and p-AR^Ser81; (2) expression of a major AR transcriptional target, prostate-specific antigen (PSA); and (3) AR transcriptional activity, probably via inhibiting the c-Jun-AR interaction by reducing c-Jun phosphorylation (p-c-Jun^Ser63). NDRG1 was also demonstrated to inhibit multiple key molecules involved in androgen-dependent and -independent signaling (namely EGFR, HER2, HER3, PI3K, STAT3, and NF-κB), which promote the development of castration-resistant prostate cancer. We also identified the cysteine-rich secretory protein/antigen 5/pathogenesis related-1 (CAP) domain of NDRG1 as vital for inhibition of AR activity. Examining NDRG1 and p-NDRG1 in PCa patient specimens revealed a significant negative correlation between NDRG1 and PSA levels in prostatectomy patients that went on to develop metastasis. These results highlight a vital role for NDRG1 in androgen signaling and its potential as a key therapeutic target and biomarker in PCa.

A pragmatic approach to Adverse Outcome Pathway (AOP) development and evaluation

The adverse outcome pathway (AOP) framework provides a practical means for organizing scientific knowledge that can be used to infer cause-effect relationships between stressor events and toxicity outcomes in intact organisms. It has reached wide acceptance as a tool to aid chemical safety assessment and regulatory toxicology by supporting a systematic way of predicting adverse health outcomes based on accumulated mechanistic knowledge. A major challenge for broader application of the AOP concept in regulatory toxicology, however, has been developing robust AOPs to a level where they are peer reviewed and accepted. This is because the amount of work required to substantiate the modular units of a complete AOP is considerable, to the point where it can take years from start to finish. To help alleviate this bottleneck, we propose a more pragmatic approach to AOP development whereby the focus becomes on smaller blocks. First, we argue that the key event relationship (KER) should be formally recognized as the core building block of knowledge assembly within the AOP knowledge base (AOP-KB), albeit framing them within full AOPs to ensure regulatory utility. Second, we argue that KERs should be developed using systematic review approaches, but only in cases where the underlying concept does not build on what is considered canonical knowledge. In cases where knowledge is considered canonical, rigorous systematic review approaches should not be required. It is our hope that these approaches will contribute to increasing the pace at which the AOP-KB is populated with AOPs with utility for chemical safety assessors and regulators.

Cornification and classical versus nonclassical androgen receptor signaling in mouse penile/preputial development

Mouse penile development is androgen-dependent. During development of male and female external genitalia, an internal ectodermal epithelial structure forms called the preputial lamina. At puberty the male preputial lamina canalizes to create the preputial space, effectively splitting into two layers: (a) the epithelial lining of the prepuce and (b) the surface epithelium of the penis. The female preputial lamina does not canalize, and instead remodels into the inverted U-shaped clitoral lamina of the adult female mouse. Androgen-dependent penile development was studied in transgenic mice with pathway-selective AR mutant transgenes through which AR signaling was activated either via the classical (AR-C) or the nonclassical pathway (AR-NC). Penile development and canalization of the preputial lamina was observed in AR-C and wild-type male mice naturally having both AR-C and AR-NC pathways. Conversely, clitoral development occurred in AR null (lacking both AR-C and AR-NC pathways) and AR-NC mice. The process of canalization of the preputial lamina seen in wild-type, AR-C and AR-C/AR-NC male mice involved cornification of the preputial lamina which involved up-regulation of keratin 10 and loricrin. Such up-regulation of these epidermal proteins was absent in the developing and adult clitoral lamina seen in wild-type female mice and AR-NC and AR null male (XY) mice. Thus, signaling through AR-C is sufficient to initiate and promote penile development and canalization of the preputial lamina, a process involving epithelial cornification.

Screening for androgen agonists using autonomously bioluminescent HEK293 reporter cells

Due to the public health concerns of endocrine-disrupting chemicals, there is an increasing demand to develop improved high-throughput detection assays for enhanced exposure control and risk assessment. A substrate-free, autobioluminescent HEK293_ARE/Gal4-Lux assay was developed to screen compounds for their ability to induce androgen receptor (AR)-mediated transcriptional activation. The assay was validated against a group of 40 recommended chemicals and achieved an overall 87.5% accuracy in qualitatively classifying positive and negative AR agonists. The HEK293_ARE/Gal4-Lux assay was demonstrated as a suitable tool for Tier 1 AR agonist screening. By eliminating exogenous substrate, this assay provided a significant advantage over traditional reporter assays by enabling higher-throughput screening with reduced testing costs while maintaining detection accuracy.

A human optimized version of the bacterial luciferase gene cassette was developed such that bioluminescence is controlled by exposure to androgen-disruptor chemicals. This cassette, along with the androgen receptor gene, was co-transfected into an HEK293 human cell host that naturally lacks hormone receptors. The resulting reporter cell line was used to screen compounds for androgenic activity in a low cost, high throughput format.

Developmental and sexual dimorphic atlas of the prenatal mouse external genitalia at the single-cell level

Birth defects of the external genitalia are among the most common in the world. Proper formation of the external genitalia requires a highly orchestrated process that involves special cell populations and sexually dimorphic hormone signaling. It is clear what the end result of the sexually dimorphic development is (a penis in the male versus clitoris in the female); however, the cell populations involved in the process remain poorly defined. Here, we used single-cell messenger RNA sequencing in mouse embryos to uncover the dynamic changes in cell populations in the external genitalia during the critical morphogenetic window. We found that overall, male and female external genitalia are largely composed of the same core cellular components. At the bipotential stage of development (embryonic day or E14.5), few differences in cell populational composition exist between male and female. Although similar in cell population composition, genetic differences in key sexual differentiation developmental pathways arise between males and females by the early (E16.5) and late (E18.5) differentiation stages. These differences include discrete cell populations with distinct responsiveness to androgen and estrogen. By late sexual differentiation (E18.5), unique cell populations in both male and female genitalia become apparent and are enriched with androgen- and estrogen-responsive genes, respectively. These data provide insights into the morphogenesis of the external genitalia that could be used to understand diseases associated with defects in the external genitalia.

Combined MD and QM/MM Investigations of Hydride Reduction of 5α-Dihydrotestosterone Catalyzed by Human 3α-Hydroxysteroid Dehydrogenase Type 3: Importance of Noncovalent Interactions

3α-Hydroxysteroid dehydrogenase (3α-HSD) is an enzyme that is essential in the regulation of the concentration of 5α-dihydrotestosterone (5α-DHT) in the prostate. It catalyzes the hydride reduction of 5α-DHT to 3α-androstanediol, which activates androgen receptors. Elucidating details about the hydride reduction of 5α-DHT by 3α-HSD and the environment around the active site of the enzyme could lead to the development of effective drugs for the treatment of prostate cancer. In this study, the X-ray crystal structure of human 3α-HSD type 3 was comprehensively evaluated. Moreover, molecular dynamics (MD) simulations and hybrid ONIOM-type quantum mechanics/molecular mechanics (QM/MM) calculations were performed using a large QM region (maximum 232 atoms). It was determined that the reaction proceeded in a single step without the formation of an alkoxide ion owing to the direct hydride reduction of the substrate by nicotinamide adenine dinucleotide phosphate (NADPH) and concerted proton transfer by Tyr55 and Lys84. Noncovalent interaction (NCI) analysis highlighted the roles of Tyr216 and Trp227 in 3α-HSD. Specifically, Tyr216 assisted the reaction by π/π interactions with the neighboring nicotinamide ring of NADP(H), whereas Trp227 played an important role in recognition of the size of the substrate by CH/π interactions.

Androgen signaling uses a writer and a reader of ADP-ribosylation to regulate protein complex assembly

Androgen signaling through the androgen receptor (AR) directs gene expression in both normal and prostate cancer cells. Androgen regulates multiple aspects of the AR life cycle, including its localization and post-translational modification, but understanding how modifications are read and integrated with AR activity has been difficult. Here, we show that ADP-ribosylation regulates AR through a nuclear pathway mediated by Parp7. We show that Parp7 mono-ADP-ribosylates agonist-bound AR, and that ADP-ribosyl-cysteines within the N-terminal domain mediate recruitment of the E3 ligase Dtx3L/Parp9. Molecular recognition of ADP-ribosyl-cysteine is provided by tandem macrodomains in Parp9, and Dtx3L/Parp9 modulates expression of a subset of AR-regulated genes. Parp7, ADP-ribosylation of AR, and AR-Dtx3L/Parp9 complex assembly are inhibited by Olaparib, a compound used clinically to inhibit poly-ADP-ribosyltransferases Parp1/2. Our study reveals the components of an androgen signaling axis that uses a writer and reader of ADP-ribosylation to regulate protein-protein interactions and AR activity.

In vitro functional characterization of androgen receptor gene mutations at arginine p.856 of the ligand-binding-domain associated with androgen insensitivity syndrome

Androgens are critical for male sex differentiation. Their actions are mediated by the androgen receptor (AR). Mutations disrupting AR function result in the androgen insensitivity syndrome (AIS). In this study, we identified in a patient with complete AIS, a novel AR mutation p.R856L. To investigate the functional properties of p.R856L, we performed functional studies. In comparison, we have characterized two already described mutations: p.R856H and p.R856C. We used a model composed of two different promoters fused to a reporter gene, two cell lines, and showed that all mutations were able to transactivate the (ARE)₂-TATA promoter expressed in CHO cells more highly. Moreover, we confirmed the pathogenicity of the p.R856L and p.R856C mutations, and their associations with complete AIS. In contrast, the p.R856H mutation, which is associated with a spectrum of AIS phenotypes, showed less severe transcriptional constraints. Altogether, our studies allowed us to better characterize arginine residue at p.R856 position.

Androgen receptors in areas of the spinal cord and brainstem: A study in adult male cats

Sex hormones, including androgens and estrogens, play an important role in autonomic, reproductive and sexual behavior. The areas that are important in these behaviors lie within the spinal cord and brainstem. Relevant dysfunctional behavior in patients with altered androgen availability or androgen receptor sensitivity might be explained by the distribution of androgens and their receptors in the central nervous system. We hypothesize that autonomic dysfunction is correlated with the androgen sensitivity of spinal cord and brainstem areas responsible for autonomic functions. In this study, androgen receptor immunoreactive (AR‐IR) nuclei in the spinal cord and brainstem were studied using the androgen receptor antibody PG21 in four uncastrated young adult male cats. A dense distribution of AR‐IR nuclei was detected in the superior layers of the dorsal horn, including lamina I. Intensely stained nuclei, but less densely distributed, were found in lamina X and preganglionic sympathetic and parasympathetic cells of the intermediolateral cell column. Areas in the caudal brainstem showing a high density of AR‐IR nuclei included the area postrema, the dorsal motor vagus nucleus and the retrotrapezoid nucleus. More cranially, the central linear nucleus in the pons contained a dense distribution of AR‐IR nuclei. The mesencephalic periaqueductal gray (PAG) showed a dense distribution of AR‐IR nuclei apart from the most central part of the PAG directly adjacent to the ependymal lining. Other areas in the mesencephalon with a dense distribution of AR‐IR nuclei were the dorsal raphe nucleus, the retrorubral nucleus, the substantia nigra and the ventral tegmental area of Tsai. It is concluded that AR‐IR nuclei are located in specific areas of the central nervous system that are involved in the control of sensory function and autonomic behavior. Furthermore, damage of these AR‐IR areas might explain related dysfunction in humans.

Structure–activity relationship analysis of a series of nonsteroidal analogues as androgen receptor antagonists

Computer-aided drug design technology was used to screen drugs in large-scale and to accelerate the progress of drug design of nonsteroidal compounds deriving from the hybridization of FDA-approved Enzalutamide and Abiraterone.

L1000 connectivity map interrogation identifies candidate drugs for repurposing as SARS-CoV-2 antiviral therapies

Adaptive clinical trials are underway to determine the efficacy of potential therapies for COVID-19, with flexibility to include emerging therapies if there is sufficient preclinical evidence for their potential utility. In silico screening of connectivity maps, which link gene expression profiles to libraries of perturbagens, may facilitate the identification of such emerging therapies. The L1000 Connectivity Map is built from samples of transcripts taken from gene expression profiles of cells in various experimental conditions followed by computational inferences of the remainder of the transcriptome. Searching the L1000 Connectivity Map for modulators of a protease that facilitates coronavirus infection identifies plausible candidate drugs for repurposing as antiviral agents against SARS-CoV-2 following further investigation.

Virtual Screening and Bioactivity Evaluation of Novel Androgen Receptor Antagonists From Anti-PCa Traditional Chinese Medicine Prescriptions

Prostate cancer (PCa), a type of malignancy that arises in the prostate gland, is the most commonly diagnosed neoplasm and the second leading cause of cancer-related deaths in men. Acquisition of resistance to conventional therapy is a major problem for PCa patient treatment. Androgen receptor (AR) signaling pathway is necessary in the pathogenesis of prostate cancer, and there is a heightened interest in finding novel AR antagonists that target AR and its regulatory pathways. In our search for novel androgen receptor antagonists, we focus on the Traditional Chinese Medicine (TCM), which has been used for thousands of years to prove effective in the treatment of cancer. In this study, we collected 653 traditional Chinese medicine prescriptions that have certain therapeutic effect to prostate cancer, including the prescriptions and even the folk prescriptions. After summarizing the frequency of herbs and gathering the natural products contained in these prescriptions, we built a natural products database to do computer-aided virtual screening and drug-like evaluation to find potential AR antagonists. Totally 25 compounds were submitted to experimental biological activity tests. Through the MTT cell proliferation experiment, 5 chemicals were found to inhibit the proliferation of LNCaP cells in a concentration-dependent manner. Especially, MoL_11 was found to have good antagonistic activity and significantly inhibit fluorescence enzyme activity by the AR reporter gene experiment. Finally, the molecular dynamics simulation method was used to study the interaction between the most active compound MoL_11 and the wild-type and F876L mutant androgen receptor (WT/F876L AR), and it was found that F876L AR could not cause resistance to MoL_11.

Androgens stimulate erythropoiesis through the DNA-binding activity of the androgen receptor in non-hematopoietic cells

BACKGROUND

Androgens function through DNA and non-DNA binding-dependent signalling of the androgen receptor (AR). How androgens promote erythropoiesis is not fully understood.

DESIGN AND METHODS

To identify the androgen signalling pathway, we treated male mice lacking the second zinc finger of the DNA-binding domain of the AR (AR^ΔZF2 ) with non-aromatizable 5α-dihydrotestosterone (5α-DHT) or aromatizable testosterone. To distinguish direct hematopoietic and non-hematopoietic mechanisms, we performed bone marrow reconstitution experiments.

RESULTS

In wild-type mice, 5α-DHT had greater erythroid activity than testosterone, which can be aromatized to estradiol. The erythroid response in wild-type mice following 5α-DHT treatment was associated with increased serum erythropoietin (EPO) and its downstream target erythroferrone, and hepcidin suppression. 5α-DHT had no erythroid activity in AR^ΔZF2 mice, proving the importance of DNA binding by the AR. Paradoxically, testosterone, but not 5α-DHT, suppressed EPO levels in AR^ΔZF2 mice, suggesting testosterone following aromatization may oppose the erythroid-stimulating effects of androgens. Female wild-type mice reconstituted with AR^ΔZF2 bone marrow cells remained responsive to 5α-DHT. In contrast, AR^ΔZF2 mice reconstituted with female wild-type bone marrow cells showed no response to 5α-DHT.

CONCLUSION

Erythroid promoting effects of androgens are mediated through DNA binding-dependent actions of the AR in non-hematopoietic cells, including stimulating EPO expression.

Regression of castration-resistant prostate cancer by a novel compound QW07 targeting androgen receptor N-terminal domain

Androgen deprivation therapy (ADT) via surgical or chemical castration frequently fails to halt lethal castration-resistant prostate cancer (CRPC), which is induced by multiple mechanisms involving constitutive androgen receptor (AR) splice variants, AR mutation, and/or de novo androgen synthesis. The AR N-terminal domain (NTD) possesses most transcriptional activity and is proposed as a potential target for CRPC drug development. We constructed a screening system targeting AR-NTD transcription activity to screening a compound library and identified a novel small molecule compound named QW07. The function evaluation and mechanism investigation of QW07 were carried out in vitro and in vivo. QW07 bound to AR-NTD directly, blocked the transactivation of AR-NTD, blocked interactions between co-regulatory proteins and androgen response elements (AREs), inhibited the expression of genes downstream of AR, and inhibited prostate cancer growth in vitro and in vivo. QW07 was demonstrated as an AR-NTD-specific antagonist with the potential to inhibit both canonical and variant-mediated AR signaling to regress the CRPC xenografts and is proposed as a lead compound for a specific antagonist targeting AR-NTD.

Reciprocal Modulation of Antiretroviral Drug and Steroid Receptor Function In Vitro

Millions of women are exposed simultaneously to antiretroviral drugs (ARVs) and progestin-based hormonal contraceptives. Yet the reciprocal modulation by ARVs and progestins of their intracellular functions is relatively unexplored. We investigated the effects of tenofovir disoproxil fumarate (TDF) and dapivirine (DPV), alone and in the presence of select steroids and progestins, on cell viability, steroid-regulated immunomodulatory gene expression, activation of steroid receptors, and anti-HIV-1 activity in vitro Both TDF and DPV modulated the transcriptional efficacy of a glucocorticoid agonist via the glucocorticoid receptor (GR) in the U2OS cell line. In TZM-bl cells, DPV induced the expression of the proinflammatory interleukin 8 (IL-8) gene while TDF significantly increased medroxyprogesterone acetate (MPA)-induced expression of the anti-inflammatory glucocorticoid-induced leucine zipper (GILZ) gene. However, peripheral blood mononuclear cell (PBMC) and ectocervical explant tissue viability and gene expression results, along with TZM-bl HIV-1 infection data, are reassuring and suggest that TDF and DPV, in combination with dexamethasone (DEX) or MPA, do not reciprocally modulate key biological effects in primary cells and tissue. We show for the first time that TDF induces progestogen-independent activation of the progesterone receptor (PR) in a cell line. The ability of TDF and DPV to influence GR and PR activity suggests that their use may be associated with steroid receptor-mediated off-target effects. This, together with cell line and individual donor gene expression responses in the primary models, raises concerns that reciprocal modulation may cause side effects in a cell- and donor-specific manner in vivo.

Design, Synthesis and Evaluation of Novel Substituted (5-methyl-1H-pyrazol-3-yl)- 1,3,4-oxadiazole as Potent Androgen Receptor Antagonist

BACKGROUND

Androgen Receptor (AR) is one of the highly explored targets for the treatment of prostate cancer. The emergence of point mutation in the Ligand Binding Domain (LBD) of AR has resulted in the development of resistance against AR antagonist. The point mutation T877A, W741L and F876L confer resistance to flutamide, bicalutamide and enzalutamide respectively. There is no AR antagonist in the present clinical set up without resistance. Hence, our aim in this study is to design a novel molecule to overcome the resistance caused by point mutation.

METHODS

Here, we developed novel AR antagonist bearing (5-methyl-1H-pyrazol-3-yl)-1, 3,4-oxadiazole core by rational drug design. The test molecules 8a-h were synthesized from the corresponding dihydrazide compounds 7a-h on treatment with phosphorous oxychloride on reflux conditions. The structure of the molecules was confirmed from spectral data such as IR, 1H-NMR, HRMS and 13C-NMR. The synthesized compounds were screened for cytotoxicity in prostate cancer cell lines LNCaP-FGC and PC3. The confirmation of AR mediated activity of the test compounds was confirmed by gene expression study. The interaction of the best active ligands with mutant AR was predicted and drug design was rationalized through docking studies.

RESULTS

The test compounds 8a-h were synthesized and the structures were conformed using suitable techniques like IR, 1H-NMR, HRMS and 13C-NMR. Among the tested compounds, 8b and 8d showed potent antiproliferative activity against mutant AR cell lines. Further, these compounds significantly decreased the gene expression of prostate cancer biomarkers.

CONCLUSION

In this study, we have identified a potential hit molecule for AR antagonism that could be further developed to obtain a potent clinical candidate.

Proteomics contribution to the elucidation of the steroid hormone receptors functions

Steroid hormones have far-ranging biological impacts and more are continuously being uncovered. Over the last decades, proteomics approaches have become key to better understand biological processes. Due to multiple technical breakthroughs allowing for the concurrent identification and/or quantification of thousands of analytes using mass spectrometers, researchers employing proteomics tools today can now obtain truly holistic views of multiple facets of the human proteome. Here, we review how the field of proteomics has contributed to discoveries about steroid hormones, their receptors and their impact on human pathologies. In particular, the involvement of steroid receptors in cancer initiation, development, metastasis and treatment will be highlighted. Techniques at the forefront of the proteomics field will also be discussed to present how they can contribute to a better understanding of steroid hormone receptors.

Optimized ChIP-seq method facilitates transcription factor profiling in human tumors

This study presents an optimized ChIP-seq protocol to enhance transcription factor profiling in human tumours, enabling the analysis of highly challenging samples, including core needle biopsies.

Chromatin immunoprecipitation (ChIP)-seq analyses of transcription factors in clinical specimens are challenging due to the technical limitations and low quantities of starting material, often resulting in low enrichments and poor signal-to-noise ratio. Here, we present an optimized protocol for transcription factor ChIP-seq analyses in human tissue, yielding an ∼100% success rate for all transcription factors analyzed. As proof of concept and to illustrate general applicability of the approach, human tissue from the breast, prostate, and endometrial cancers were analyzed. In addition to standard formaldehyde fixation, disuccinimidyl glutarate was included in the procedure, greatly increasing data quality. To illustrate the sensitivity of the optimized protocol, we provide high-quality ChIP-seq data for three independent factors (AR, FOXA1, and H3K27ac) from a single core needle prostate cancer biopsy specimen. In summary, double-cross-linking strongly improved transcription factor ChIP-seq quality on human tumor samples, further facilitating and enhancing translational research on limited amounts of tissue.

Enzalutamide therapy for advanced prostate cancer: efficacy, resistance and beyond

The androgen receptor drives the growth of metastatic castration-resistant prostate cancer. This has led to the development of multiple novel drugs targeting this hormone-regulated transcription factor, such as enzalutamide – a potent androgen receptor antagonist. Despite the plethora of possible treatment options, the absolute survival benefit of each treatment separately is limited to a few months. Therefore, current research efforts are directed to determine the optimal sequence of therapies, discover novel drugs effective in metastatic castration-resistant prostate cancer and define patient subpopulations that ultimately benefit from these treatments. Molecular studies provide evidence on which pathways mediate treatment resistance and may lead to improved treatment for metastatic castration-resistant prostate cancer. This review provides, firstly a concise overview of the clinical development, use and effectiveness of enzalutamide in the treatment of advanced prostate cancer, secondly it describes translational research addressing enzalutamide response vs resistance and lastly highlights novel potential treatment strategies in the enzalutamide-resistant setting.

Targeting the Hsp40/Hsp70 Chaperone Axis as a Novel Strategy to Treat Castration-Resistant Prostate Cancer

Castration-resistant prostate cancer (CRPC) is characterized by reactivation of androgen receptor (AR) signaling, in part by elevated expression of AR splice variants (ARv) including ARv7, a constitutively active, ligand binding domain (LBD)-deficient variant whose expression has been correlated with therapeutic resistance and poor prognosis. In a screen to identify small-molecule dual inhibitors of both androgen-dependent and androgen-independent AR gene signatures, we identified the chalcone C86. Binding studies using purified proteins and CRPC cell lysates revealed C86 to interact with Hsp40. Pull-down studies using biotinylated-C86 found Hsp40 present in a multiprotein complex with full-length (FL-) AR, ARv7, and Hsp70 in CRPC cells. Treatment of CRPC cells with C86 or the allosteric Hsp70 inhibitor JG98 resulted in rapid protein destabilization of both FL-AR and ARv, including ARv7, concomitant with reduced FL-AR- and ARv7-mediated transcriptional activity. The glucocorticoid receptor, whose elevated expression in a subset of CRPC also leads to androgen-independent AR target gene transcription, was also destabilized by inhibition of Hsp40 or Hsp70. In vivo, Hsp40 or Hsp70 inhibition demonstrated single-agent and combinatorial activity in a 22Rv1 CRPC xenograft model. These data reveal that, in addition to recognized roles of Hsp40 and Hsp70 in FL-AR LBD remodeling, ARv lacking the LBD remain dependent on molecular chaperones for stability and function. Our findings highlight the feasibility and potential benefit of targeting the Hsp40/Hsp70 chaperone axis to treat prostate cancer that has become resistant to standard antiandrogen therapy.Significance: These findings highlight the feasibility of targeting the Hsp40/Hsp70 chaperone axis to treat CRPC that has become resistant to standard antiandrogen therapy. Cancer Res; 78(14); 4022-35. ©2018 AACR.

Treatment-induced changes in the androgen receptor axis: Liquid biopsies as diagnostic/prognostic tools for prostate cancer

Prostate cancer progression and treatment relapse is associated with changes in the androgen receptor axis, and analysis of alternations of androgen receptor signaling is valuable for prognostics and treatment optimization. The profile of androgen receptor axis is currently obtained from biopsy specimens, which are not always easy to obtain. Moreover, the information acquired only provides a snapshot of the tumor biology, with strict spatial and temporal limitations. On the other hand, circulation is easily accessible source of both circulating tumor cells and circulating tumor DNA, which can be sampled at numerous time points. This Review will explore the potential use of androgen receptor axis alternations detectable in the blood in therapeutic decision-making and precision medicine for advancing metastatic castration-resistant prostate cancer.

Prostate cancer health disparities: An immuno-biological perspective

Prostate cancer (PCa) is the most commonly diagnosed malignancy in males, and, in the United States, is the second leading cause of cancer-related death for men older than 40 years. There is a higher incidence of PCa for African Americans (AAs) than for European-Americans (EAs). Investigations related to the incidence of PCa-related health disparities for AAs suggest that there are differences in the genetic makeup of these populations. Other differences are environmentally induced (e.g., diet and lifestyle), and the exposures are different. Men who immigrate from Eastern to Western countries have a higher risk of PCa than men in their native countries. However, the number of immigrants developing PCa is still lower than that of men in Western countries, suggesting that genetic factors are involved in the development of PCa. Altered genetic polymorphisms are associated with PCa progression. Androgens and the androgen receptor (AR) are involved in the development and progression of PCa. For populations with diverse racial/ethnic backgrounds, differences in lifestyle, diet, and biology, including genetic mutations/polymorphisms and levels of androgens and AR, are risk factors for PCa. Here, we provide an immuno-biological perspective on PCa in relation to racial/ethnic disparities and identify factors associated with the disproportionate incidence of PCa and its clinical outcomes.

Innate Sex Bias of Staphylococcus aureus Skin Infection Is Driven by α-Hemolysin

Numerous studies have reported sex bias in infectious diseases, with bias direction dependent on pathogen and site of infection. Staphylococcus aureus is the most common cause of skin and soft tissue infections (SSTIs), yet sex bias in susceptibility to S. aureus SSTI has not been described. A search of electronic health records revealed an odds ratio of 2.4 for S. aureus SSTI in males versus females. To investigate the physiological basis of this bias, we compared outcomes between male and female mice in a model of S. aureus dermonecrosis. Consistent with the epidemiological data, female mice were better protected against SSTI, with reduced dermonecrosis followed later by increased bacterial clearance. Protection in females was disrupted by ovariectomy and restored by short-term estrogen administration. Importantly, this sex bias was mediated by a sex-specific response to the S. aureus-secreted virulence factor α-hemolysin (Hla). Infection with wild-type S. aureus suppressed inflammatory cytokine production in the skin of female, but not male, mice when compared with infection with an isogenic hla deletion mutant. This differential response was conserved following injection with Hla alone, demonstrating a direct response to Hla independent of bacterial burden. Additionally, neutrophils, essential for clearing S. aureus, demonstrated sex-specific S. aureus bactericidal capacity ex vivo. This work suggests that sex-specific skin innate responsiveness to Hla and neutrophil bactericidal capacity play important roles in limiting S. aureus SSTI in females. Understanding the molecular mechanisms controlling this sex bias may reveal novel targets to promote host innate defense against S. aureus skin infection.

A Molecular Modeling Study of the Hydroxyflutamide Resistance Mechanism Induced by Androgen Receptor Mutations

Hydroxyflutamide (HF), an active metabolite of the first generation antiandrogen flutamide, was used in clinic to treat prostate cancer targeting androgen receptor (AR). However, a drug resistance problem appears after about one year’s treatment. AR T877A is the first mutation that was found to cause a resistance problem. Then W741C_T877A and F876L_T877A mutations were also reported to cause resistance to HF, while W741C and F876L single mutations cannot. In this study, molecular dynamics (MD) simulations combined with the molecular mechanics generalized Born surface area (MM-GBSA) method have been carried out to analyze the interaction mechanism between HF and wild-type (WT)/mutant ARs. The obtained results indicate that AR helix 12 (H12) plays a pivotal role in the resistance of HF. It can affect the coactivator binding site at the activation function 2 domain (AF2, surrounded by H3, H4, and H12). When H12 closes to the AR ligand-binding domain (LBD) like a lid, the coactivator binding site can be formed to promote transcription. However, once H12 is opened to expose LBD, the coactivator binding site will be distorted, leading to invalid transcription. Moreover, per-residue free energy decomposition analyses indicate that N705, T877, and M895 are vital residues in the agonist/antagonist mechanism of HF.

Iminoenamine based novel androgen receptor antagonist exhibited anti-prostate cancer activity in androgen independent prostate cancer cells through inhibition of AKT pathway

Treatment by androgen receptor (AR) antagonists is one of the regimens for prostate cancer. The prolonged treatment with AR antagonist leads to the expression of point mutation in the ligand binding domain of the AR. This point mutation causes resistance to AR antagonist by converting them into an agonist. The T887A mutated AR was frequently expressed in androgen independent prostate cancer (AIPC) patients. Through literature survey and molecular modelling, we have identified a novel AR antagonist having a bulky β-iminoenamine BF2 complex scaffold. The tested and standard ligands were screened in AR positive (LNCaP, MCF-7 and MDA-MB-453), AR negative (PC3), and non-cancerous (3T3) cell lines through anti-proliferation assay. The ligand, ARA3 was the most potent molecule among all the tested ligands and was 7.6 folds selective for AR positive cell lines. The mechanism of anti-prostate cancer activity of ARA3 was confirmed by western blot, qPCR, and apoptotic assays in LNCaP (T887A positive AR) cells. Structural activity relationship was derived by correlating the in-vitro and in-silico data. Consequently, we have identified the essential functional groups that could prevent the resistance concerning mutant AR. The ARA3 induces the apoptosis in AIPC cells by preventing the AR mediated activation of AKT pathway. The bicalutamide did not induce the apoptosis because it failed to prevent the AR mediated activation of AKT.

Androgens and androgen receptor signaling contribute to ovarian development in the chicken embryo

Androgens and androgen receptor (AR) signaling play important roles throughout development. In the chicken, AR signaling is involved in reproduction; however, its specific role is unclear. We show that AR signaling is involved in the normal development of the female embryonic gonads. The AR mRNA level was detected in male and female embryonic gonads by quantitative RT-PCR, and its expression was higher in females than in males at all developmental stages examined. In female embryos, the AR localized to nuclei of cells in the left gonad. Although AR expression was low in the majority of the medulla, high expression was detected in cells of lacunae within the medulla. In addition, AR expression increased in cells of cortical cords within the cortex with the progression of development. AR expression in the right gonad was lower than that in left gonad throughout development. In the male gonad, the AR localized to the cytoplasm of cells in seminiferous tubules at all stages. Female AR knockdown (ARKD) embryos infected with a retrovirus expressing micro RNAs targeting the AR showed normal asymmetric gonads (development of the left and depression of the right gonads), whereas the number of lacunae decreased. Furthermore, there was a disruption in the structure of cortical cords. By contrast, the gonads of ARKD males developed normally during embryogenesis. These results indicate that androgens and AR signaling are essential for the development of lacunae and cortical cords in gonads of female embryos.

A review of estrogen receptor/androgen receptor genomics in male breast cancer

Male breast cancer is a rare disease, of which little is known. In contrast to female breast cancer, the very vast majority of all cases are positive for estrogen receptor alpha (ERα), implicating the function of this steroid hormone receptor in tumor development and progression. Consequently, adjuvant treatment of male breast cancer revolves around inhibition of ERα. In addition, the androgen receptor (AR) gradually receives more attention as a relevant novel target in breast cancer treatment. Importantly, the rationale of treatment decision making is strongly based on parallels with female breast cancer. Yet, prognostic indicators are not necessarily the same in breast cancer between both genders, complicating translatability of knowledge developed in female breast cancer toward male patients. Even though ERα and AR are expressed both in female and male disease, are the genomic functions of both steroid hormone receptors conserved between genders? Recent studies have reported on mutational and epigenetic similarities and differences between male and female breast cancer, further suggesting that some features are strongly conserved between the two diseases, whereas others are not. This review critically discusses the recent developments in the study of male breast cancer in relation to ERα and AR action and highlights the potential future studies to further elucidate the genomic regulation of this rare disease.

A Tale of Two Signals: AR and WNT in Development and Tumorigenesis of Prostate and Mammary Gland

Prostate cancer (PCa) is one of the most common cancers and among the leading causes of cancer deaths for men in industrialized countries. It has long been recognized that the prostate is an androgen-dependent organ and PCa is an androgen-dependent disease. Androgen action is mediated by the androgen receptor (AR). Androgen deprivation therapy (ADT) is the standard treatment for metastatic PCa. However, almost all advanced PCa cases progress to castration-resistant prostate cancer (CRPC) after a period of ADT. A variety of mechanisms of progression from androgen-dependent PCa to CRPC under ADT have been postulated, but it remains largely unclear as to when and how castration resistance arises within prostate tumors. In addition, AR signaling may be modulated by extracellular factors among which are the cysteine-rich glycoproteins WNTs. The WNTs are capable of signaling through several pathways, the best-characterized being the canonical WNT/β-catenin/TCF-mediated canonical pathway. Recent studies from sequencing PCa genomes revealed that CRPC cells frequently harbor mutations in major components of the WNT/β-catenin pathway. Moreover, the finding of an interaction between β-catenin and AR suggests a possible mechanism of cross talk between WNT and androgen/AR signaling pathways. In this review, we discuss the current knowledge of both AR and WNT pathways in prostate development and tumorigenesis, and their interaction during development of CRPC. We also review the possible therapeutic application of drugs that target both AR and WNT/β-catenin pathways. Finally, we extend our review of AR and WNT signaling to the mammary gland system and breast cancer. We highlight that the role of AR signaling and its interaction with WNT signaling in these two hormone-related cancer types are highly context-dependent.

Androgen receptor-dependent and -independent mechanisms driving prostate cancer progression: Opportunities for therapeutic targeting from multiple angles

Despite aggressive treatment for localized cancer, prostate cancer (PC) remains a leading cause of cancer-related death for American men due to a subset of patients progressing to lethal and incurable metastatic castrate-resistant prostate cancer (CRPC). Organ-confined PC is treated by surgery or radiation with or without androgen deprivation therapy (ADT), while options for locally advanced and disseminated PC include radiation combined with ADT, or systemic treatments including chemotherapy. Progression to CRPC results from failure of ADT, which targets the androgen receptor (AR) signaling axis and inhibits AR-driven proliferation and survival pathways. The exact mechanisms underlying the transition from androgen-dependent PC to CRPC remain incompletely understood. Reactivation of AR has been shown to occur in CRPC despite depletion of circulating androgens by ADT. At the same time, the presence of AR-negative cell populations in CRPC has also been identified. While AR signaling has been proposed as the primary driver of CRPC, AR-independent signaling pathways may represent additional mechanisms underlying CRPC progression. Identification of new therapeutic strategies to target both AR-positive and AR-negative PC cell populations and, thereby, AR-driven as well as non-AR-driven PC cell growth and survival mechanisms would provide a two-pronged approach to eliminate CRPC cells with potential for synthetic lethality. In this review, we provide an overview of AR-dependent and AR-independent molecular mechanisms which drive CRPC, with special emphasis on the role of the Jak2-Stat5a/b signaling pathway in promoting castrate-resistant growth of PC through both AR-dependent and AR-independent mechanisms.

PTTG1, A novel androgen responsive gene is required for androgen-induced prostate cancer cell growth and invasion

Androgens (AR) play an important role in initiation and progression of prostate cancer. It has been shown that AR exert their effects mainly through the androgen-activated AR which binds to androgen response elements (AREs) in the regulatory regions of target genes to regulate the transcription of androgen-responsive genes, thus, identification of AR downstream target gene is critical to understand androgen function in prostate cancer. In this study, our results showed that androgen treatment of LNCaP cells induced PTTG1 expression, which was blocked by the androgen receptor antagonist, Casodex. Bioinformatics analysis and experiments using PTTG1 promoter deletion mutants showed that the PTTG1 promoter contains a putative androgen response element (ARE), which localizes in the -851 to -836 region of the promoter. Androgen activated androgen receptor (AR) binding to this ARE was confirmed by Chromatin immunoprecipitation (ChIP) assay. Furthermore, Knockdown of PTTG1 expression using short hairpin RNA significantly reduced androgen-induced LNCaP cell growth and invasion. In addition, we showed PTTG1 is highly expressed in metastasis prostate cancer tissue. These results suggest that PTTG1 is a novel downstream target gene of androgen receptor and take part in prostate cancer proliferation and metastasis.

Inhibition effect of cypermethrin mediated by co-regulators SRC-1 and SMRT in interleukin-6-induced androgen receptor activation

It is hypothesized that the pesticide cypermethrin may induce androgen receptor (AR) antagonism via ligand-independent mechanisms. The Real-Time Cell Analysis (RTCA) iCELLigence system was used to investigate the inhibitory effect of cypermethrin on interleukin-6 (IL-6)-induced ligand-independent LNCaP cell growth. Then, the mammalian two-hybrid assays were applied to clarify whether the mechanism of IL-6-induced AR antagonism of cypermethrin was associated with the interactions of the AR and co-activator steroid receptor co-activator-1 (SRC-1) and co-repressor silencing mediator for retinoid and thyroid hormone receptors (SMRT). Cypermethrin inhibited the LNCaP cell growth induced by IL-6. The interactions of AR-SRC-1 and AR-SMRT mediated by IL-6 were suppressed by cypermethrin. The results indicate that the IL-6-mediated AR antagonism induced by cypermethrin is related to repress the recruitment of co-regulators SRC-1 and SMRT to the AR in a ligand-independent manner. Inhibition of the interactions of AR-SRC-1 and AR-SMRT mediated by IL-6 contributes to the AR antagonism induced by cypermethrin.

Androgen receptor profiling predicts prostate cancer outcome

Prostate cancer is the second most prevalent malignancy in men. Biomarkers for outcome prediction are urgently needed, so that high-risk patients could be monitored more closely postoperatively. To identify prognostic markers and to determine causal players in prostate cancer progression, we assessed changes in chromatin state during tumor development and progression. Based on this, we assessed genomewide androgen receptor/chromatin binding and identified a distinct androgen receptor/chromatin binding profile between primary prostate cancers and tumors with an acquired resistance to therapy. These differential androgen receptor/chromatin interactions dictated expression of a distinct gene signature with strong prognostic potential. Further refinement of the signature provided us with a concise list of nine genes that hallmark prostate cancer outcome in multiple independent validation series. In this report, we identified a novel gene expression signature for prostate cancer outcome through generation of multilevel genomic data on chromatin accessibility and transcriptional regulation and integration with publically available transcriptomic and clinical datastreams. By combining existing technologies, we propose a novel pipeline for biomarker discovery that is easily implementable in other fields of oncology.

Androgen-Sensitized Apoptosis of HPr-1AR Human Prostate Epithelial Cells

Androgen receptor (AR) signaling is crucial to the development and homeostasis of the prostate gland, and its dysregulation mediates common prostate pathologies. The mechanisms whereby AR regulates growth suppression and differentiation of luminal epithelial cells in the prostate gland and proliferation of malignant versions of these cells have been investigated in human and rodent adult prostate. However, the cellular stress response of human prostate epithelial cells is not well understood, though it is central to prostate health and pathology. Here, we report that androgen sensitizes HPr-1AR and RWPE-AR human prostate epithelial cells to cell stress agents and apoptotic cell death. Although 5α-dihydrotestosterone (DHT) treatment alone did not induce cell death, co-treatment of HPr-1AR cells with DHT and an apoptosis inducer, such as staurosporine (STS), TNFt, or hydrogen peroxide, synergistically increased cell death in comparison to treatment with each apoptosis inducer by itself. We found that the synergy between DHT and apoptosis inducer led to activation of the intrinsic/mitochondrial apoptotic pathway, which is supported by robust cleavage activation of caspase-9 and caspase-3. Further, the dramatic depolarization of the mitochondrial membrane potential that we observed upon co-treatment with DHT and STS is consistent with increased mitochondrial outer membrane permeabilization (MOMP) in the pro-apoptotic mechanism. Interestingly, the synergy between DHT and apoptosis inducer was abolished by AR antagonists and inhibitors of transcription and protein synthesis, suggesting that AR mediates pro-apoptotic synergy through transcriptional regulation of MOMP genes. Expression analysis revealed that pro-apoptotic genes (BCL2L11/BIM and AIFM2) were DHT-induced, whereas pro-survival genes (BCL2L1/BCL-XL and MCL1) were DHT-repressed. Hence, we propose that the net effect of these AR-mediated expression changes shifts the balance of BCL2-family proteins, such that androgen signaling sensitizes mitochondria to apoptotic signaling, thus rendering HPr-1AR more vulnerable to cell death signals. Our study offers insight into AR-mediated regulation of prostate epithelial cell death signaling.

Topoisomerase 2 Alpha Cooperates with Androgen Receptor to Contribute to Prostate Cancer Progression

Overexpression of TOP2A is associated with risk of systemic progression in prostate cancer patients, and higher levels of TOP2A were found in hormone-resistant cases. To elucidate the mechanism by which high levels of TOP2A contribute to tumor progression we generated TOP2A overexpressing prostate cancer cell lines. We show that TOP2A promotes tumor aggressiveness by inducing chromosomal rearrangements of genes that contribute to a more invasive phenotype. Anti-androgen treatment alone was ineffective in killing TOP2A overexpressing cells due to activation of an androgen receptor network. TOP2A poisons killed tumor cells more efficiently early in the progression course, while at later stages they provided greater benefit when combined with anti-androgen therapy. Mechanistically, we find that TOP2A enhances androgen signaling by facilitating transcription of androgen responsive genes, thereby promoting tumor cell growth. These studies revealed a relationship between TOP2A and androgen receptor signaling pathway that contributes to prostate cancer progression and confers sensitivity to treatments.

Expression of androgen receptor target genes in skeletal muscle

We aimed to determine the mechanisms of the anabolic actions of androgens in skeletal muscle by investigating potential androgen receptor (AR)-regulated genes in in vitro and in vivo models. The expression of the myogenic regulatory factor myogenin was significantly decreased in skeletal muscle from testosterone-treated orchidectomized male mice compared to control orchidectomized males, and was increased in muscle from male AR knockout mice that lacked DNA binding activity (AR^ΔZF2) versus wildtype mice, demonstrating that myogenin is repressed by the androgen/AR pathway. The ubiquitin ligase Fbxo32 was repressed by 12 h dihydrotestosterone treatment in human skeletal muscle cell myoblasts, and c-Myc expression was decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle, and increased in AR^ΔZF2 muscle. The expression of a group of genes that regulate the transition from myoblast proliferation to differentiation, Tceal7, p57^Kip2, Igf2 and calcineurin Aa, was increased in AR^ΔZF2 muscle, and the expression of all but p57^Kip2 was also decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle. We conclude that in males, androgens act via the AR in part to promote peak muscle mass by maintaining myoblasts in the proliferative state and delaying the transition to differentiation during muscle growth and development, and by suppressing ubiquitin ligase-mediated atrophy pathways to preserve muscle mass in adult muscle.