Molecular basis of androgen insensitivity

Looking beyond the ER, PR, and HER2: what's new in the ARsenal for combating breast cancer?

Breast cancer (BrCa) is a complex and heterogeneous disease with diverse molecular subtypes, leading to varied clinical outcomes and posing significant treatment challenges. The increasing global burden of BrCa, particularly in low- and middle-income countries, underscores the urgent need for more effective therapeutic strategies. The androgen receptor (AR), expressed in a substantial proportion of breast cancer cases, has emerged as a potential biomarker and therapeutic target. In breast cancer, AR exhibits diverse functions across subtypes, often interacting with other hormone receptors, thereby influencing tumor progression and treatment responses. This intricate interplay is further complicated by the presence of constitutively expressed AR splice variants (AR-Vs) that drive resistance to AR-targeting therapies through structural rearrangements in the domains and activation of aberrant signaling pathways. Although AR-targeting drugs, initially developed for prostate cancer (PCa), have shown promise in AR-positive breast cancer, significant gaps remain in understanding AR's precise functions and therapeutic potential. The systemic management of breast cancer is guided primarily by theranostic biomarkers; ER, PR, HER2, and Ki67 which also dictate the breast cancer classification. The ubiquitous expression of AR in BrCa and the emergence of AR-Vs can assist the management of disease complementing the standard of care. This article provides a comprehensive overview of AR and its splice variants in the context of breast cancer, highlighting their prognostic and predictive value across different subtypes looking beyond the conventional ER, PR, and HER2 status. This review also raises the possibility of using AR splice variants in predicting tumor aggressiveness. From the settings of developing nations, this may provide useful insight by integrating recent advances in AR-targeted therapies and exploring their translational potential, emphasizing the critical need for further research to optimize AR-based therapeutic strategies for breast cancer management.

ER Negative Breast Cancer and miRNA: There Is More to Decipher Than What the Pathologist Can See!

Breast cancer (BC), the most prevalent cancer in women, is a heterogenous disease. Despite advancements in BC diagnosis, prognosis, and therapeutics, survival rates have drastically decreased in the metastatic setting. Therefore, BC still remains a medical challenge. The evolution of high-throughput technology has highlighted gaps in the classification system of BCs. Of particular interest is the notorious triple negative BC, which was recounted as being heterogenous itself and it overlaps with distinct subtypes, namely molecular apocrine (MA) and luminal androgen (LAR) BCs. These subtypes are, even today, still misdiagnosed and poorly treated. As such, researchers and clinicians have been looking for ways through which to refine BC classification in order to properly understand the initiation, development, progression, and the responses to the treatment of BCs. One tool is biomarkers and, specifically, microRNA (miRNA), which are highly reported as associated with BC carcinogenesis. In this review, the diverse roles of miRNA in estrogen receptor negative (ER-) and androgen receptor positive (AR+) BC are depicted. While highlighting their oncogenic and tumor suppressor functions in tumor progression, we will discuss their diagnostic, prognostic, and predictive biomarker potentials, as well as their drug sensitivity/resistance activity. The association of several miRNAs in the KEGG-reported pathways that are related to ER-BC carcinogenesis is presented. The identification and verification of accurate miRNA panels is a cornerstone for tackling BC classification setbacks, as is also the deciphering of the carcinogenesis regulators of ER - AR + BC.

Advancing Epidemiology and Genetic Approaches for the Treatment of Spinal and Bulbar Muscular Atrophy: Focus on Prevalence in the Indigenous Population of Western Canada

Spinal and bulbar muscular atrophy (SBMA), also known as Kennedy's disease, is a debilitating neuromuscular disease characterized by progressive muscular weakness and neuronal degeneration, affecting 1-2 individuals per 100,000 globally. While SBMA is relatively rare, recent studies have shown a significantly higher prevalence of the disease among the indigenous population of Western Canada compared to the general population. The disease is caused by a pathogenic expansion of polyglutamine residues in the androgen receptor protein, which acts as a key transcriptional regulator for numerous genes. SBMA has no cure, and current treatments are primarily supportive and focused on symptom management. Recently, a form of precision medicine known as antisense therapy has gained traction as a promising therapeutic option for numerous neuromuscular diseases. Antisense therapy uses small synthetic oligonucleotides to confer therapeutic benefit by acting on pathogenic mRNA molecules, serving to either degrade pathogenic mRNA transcripts or helping to modulate splicing. Recent studies have explored the suitability of antisense therapy for the treatment of SBMA, primarily focused on gene therapy and antisense-mediated mRNA knockdown approaches. Advancements in understanding the pathogenesis of SBMA and the development of targeted therapies offer hope for improved quality of life for individuals affected by this debilitating condition. Continued research is essential to optimize these genetic approaches, ensuring their safety and efficacy.

Addressing the Reciprocal Crosstalk between the AR and the PI3K/AKT/mTOR Signaling Pathways for Prostate Cancer Treatment

The reduction in androgen synthesis and the blockade of the androgen receptor (AR) function by chemical castration and AR signaling inhibitors represent the main treatment lines for the initial stages of prostate cancer. Unfortunately, resistance mechanisms ultimately develop due to alterations in the AR pathway, such as gene amplification or mutations, and also the emergence of alternative pathways that render the tumor less or, more rarely, completely independent of androgen activation. An essential oncogenic axis activated in prostate cancer is the phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway, as evidenced by the frequent alterations of the negative regulator phosphatase and tensin homolog (PTEN) and by the activating mutations in PI3K subunits. Additionally, crosstalk and reciprocal feedback loops between androgen signaling and the PI3K/AKT/mTOR signaling cascade that activate pro-survival signals and play an essential role in disease recurrence and progression have been evidenced. Inhibitors addressing different players of the PI3K/AKT/mTOR pathway have been evaluated in the clinic. Only a limited benefit has been reported in prostate cancer up to now due to the associated side effects, so novel combination approaches and biomarkers predictive of patient response are urgently needed. Here, we reviewed recent data on the crosstalk between AR signaling and the PI3K/AKT/mTOR pathway, the selective inhibitors identified, and the most advanced clinical studies, with a focus on combination treatments. A deeper understanding of the complex molecular mechanisms involved in disease progression and treatment resistance is essential to further guide therapeutic approaches with improved outcomes.

Non-canonical androgen signaling pathways and implications in prostate cancer

Androgen signaling is a critical determinant of timely and proper development of all male organs including the prostate. Maturation of prostate and its neoplastic transformation is intricately associated with accurate androgen signaling. Ablation of androgen has therefore been the primary treatment mechanism of Prostate cancer (PCa) patients for several decades. Upon removal, the tumor recedes for a while, yet it reappears soon, in an androgen independent state, untreatable by current therapeutic regimens. Studies reveal that apart from the classical androgen signaling pathway known and targeted for almost a century, there exist several non-canonical pathways, with marked impact on classical androgen signaling and PCa growth. These include non-genomic signaling by androgens via alternate membrane GPCRs, signaling by non-androgens that ultimately impact the androgen signaling pathway, or an integration of non-genomic and genomic response as seen in case of protein kinase A activation. Accurate understanding of these various non-canonical androgen signaling pathways and their influence on the typical androgen signaling pathway can help design important interventions for PCa patients. This review analyses in detail the various non-classical androgen signaling pathways and their impact, if any, on classical mode of androgen action and PCa.

Revisiting the physiological role of androgens in women

INTRODUCTION

Extensive research underlines the critical functions of androgens in females. Nevertheless, the precise mechanisms of their action are poorly understood. Here, we review the existing literature regarding the physiological role of androgens in women throughout life.

AREAS COVERED

Several studies show that androgen receptors (ARs) are broadly expressed in numerous female tissues. They are essential for many physiological processes, including reproductive, sexual, cardiovascular, bone, muscle, and brain health. They are also involved in adipose tissue and liver function. Androgen levels change with the menstrual cycle and decrease in the first decades of life, independently of menopause.

EXPERT OPINION

To date, studies are limited by including small numbers of women, the difficulty of dosing androgens, and their cyclical variations. In particular, whether androgens play any significant role in regulating the establishment of pregnancy is poorly understood. The neural functions of ARs have also been investigated less thoroughly, although it is expressed at high levels in brain structures. Moreover, the mechanism underlying the decline of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) with age is unclear. Other factors, including estrogen's effect on adrenal androgen production, reciprocal regulation of ARs, and non-classical effects of androgens, remain to be determined.

Whole exome sequencing reveals copy number variants in individuals with disorders of sex development

Complete androgen insensitivity syndrome (CAIS), where 46,XY individuals present as female, is caused by variants in the androgen receptor gene (AR). We analyzed the DNA of a patient with suspected CAIS using a targeted gene sequencing panel and whole exome sequencing (WES) but did not detect any small nucleotide variants in AR. Analysis of WES data using our bioinformatics pipeline designed to detect copy number variations (CNV) uncovered a rare duplication of exon 2 of AR. Using array comparative genomic hybridization, the duplication was found to span 43.6 kb and is predicted to cause a frameshift and loss of AR protein. We confirmed the power of our WES-CNV detection protocol by identifying pathogenic CNVs in FSHR and NR5A1 in previously undiagnosed patients with disorders of sex development. Our findings illustrate the usefulness of CNV analysis in WES data to detect pathogenic genomic changes that may go undetected using only standard analysis protocols.

Genetic architecture of motor neuron diseases

Motor neuron diseases (MNDs) are rare and frequently fatal neurological disorders in which motor neurons within the brainstem and spinal cord regions slowly die. MNDs are primarily caused by genetic mutations, and > 100 different mutant genes in humans have been discovered thus far. Given the fact that many more MND-related genes have yet to be discovered, the growing body of genetic evidence has offered new insights into the diverse cellular and molecular mechanisms involved in the aetiology and pathogenesis of MNDs. This search may aid in the selection of potential candidate genes for future investigation and, eventually, may open the door to novel interventions to slow down disease progression. In this review paper, we have summarized detailed existing research findings of different MNDs, such as amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), spinal bulbar muscle atrophy (SBMA) and hereditary spastic paraplegia (HSP) in relation to their complex genetic architecture.

Association of X Chromosome Aberrations with Male Infertility

Male infertility is caused by spermatogenetic failure, clinically noted as oligoor azoospermia. Approximately 20% of infertile patients carry a genetic defect. The most frequent genetic defect leading to azoospermia (or severe oligozoospermia) is Klinefelter syndrome (47, XXY), which is numerical chromosomal abnormality and Y- structural chromosome aberration. The human X chromosome is the most stable of all human chromosomes. The X chromosome is loaded with regions of acquired, rapidly evolving genes. The X chromosome may actually play an essential role in male infertility and sperm production. Here we will describe X chromosome aberrations, which are associated with male infertility.

Androgen receptor variants: RNA-based mechanisms and therapeutic targets

Prostate cancer is the second leading cause of male cancer death in the United States. The androgen receptor (AR) transcription factor is a master regulator of normal glandular homeostasis in the prostate, as well as growth and survival of prostate cancer cells. Therefore, AR-targeted therapies are effective for improving overall survival of patients with advanced prostate cancer that is incurable by surgery or radiation. However, prostate cancer will inevitably progress on AR-targeted therapies to a castration-resistant prostate cancer (CRPC) phenotype that accounts for virtually all prostate cancer-specific death. mRNA transcript variants of the AR gene are expressed in CRPC cells and can be translated to produce AR variant (AR-V) proteins that function as ligand-independent, constitutively active transcription factors. AR-Vs are able to support growth of CRPC cells by promoting expression of AR target genes that are normally suppressed by AR-targeted therapies. Knowledge of mechanisms that govern expression of AR-Vs is incomplete. Studies have shown genomic rearrangements of the AR gene underlie expression of diverse AR-Vs in certain CRPC tumors, but post-transcriptional processes represent a broader regulatory mechanism for expression of AR-Vs in CRPC. This review focuses on alternative splicing, 3' end processing, miRNA-mediated mRNA repression, of AR and AR-V expression and the potential these mechanisms hold as therapeutic targets for CRPC.

Complete androgen insensitivity syndrome in a 13-year-old Lebanese child, reared as female, with bilateral inguinal hernia: a case report

Background

Androgen insensitivity syndrome is a rare X-linked disorder of sex development, caused by mutations in the androgen receptor. In this case, a 13-year-old child, reared as female, presenting for primary amenorrhea, was diagnosed with complete androgen insensitivity syndrome.

Case presentation

A 13-year-old Caucasian child, reared as female, presents with primary amenorrhea. Physical examination revealed female appearance and a short vagina with blind-ended pouch. Laboratory examination showed high levels of testosterone and anti-Müllerian hormone; uterus and ovaries were absent. Karyotype confirmed a 46,XY pattern. Deoxyribonucleic acid analysis of the androgen receptor gene revealed a homozygous mutation p.R856C in exon 7. Gender was assigned as female, and she was started on hormonal therapy and underwent gonadectomy.

Conclusion

Androgen insensitivity syndrome comprises a large spectrum of presentations. High index of suspicion is needed. Investigation of girls with bilateral inguinal hernia is critical.

CAG Repeats in the androgen receptor gene is associated with oligozoospermia and teratozoospermia in infertile men in Jordan

CAG trinucleotide repeats are coded for the polyglutamine tract in the N-terminal of the androgen receptor (AR) gene which varies in normal individuals from 6 to 36 residues. In this study, we inspected the impact of the CAG repeats on the spermatogenic defects by measuring the size of AR-CAG repeats length in a cohort of 260infertile and 169 fertile Jordanian men. The infertile group included three subgroups of a zoospermic, oligozoospermic and teratozoospermia men. The CAG allele size was determined by direct sequencing. The results showed a significant association between the length of the AR-CAG repeats and men's infertility (p = .001). In particular, the current cohort demonstrated a significant association between the AR-CAG length polymorphism and oligozoospermia (p < .001) and teratozoospermia (p < .001) but not azoospermia. According to distributions of allele frequency, the risk of oligozoospermia was 5.5-fold greater than normal when alleles frequency > 20 repeats, while the risk of teratozoospermia was > 10.6 folds greater than normal when allele frequency > 22 repeats. In conclusion, our results underscored that the long repeats of the AR-CAG polymorphism within the normal range might be associated with abnormal spermatogenesis such as teratozoospermia and oligozoospermia and contributing to infertility in Jordanian men.

Role of androgen and microRNA in triple-negative breast cancer

Breast cancer (BC) is the most frequent type of malignancy affecting females worldwide. Molecular-based studies resulted in an identification of at least four subtypes of breast carcinoma, including luminal A and luminal B, Human growth factor receptor (HER-2)-enriched and triple-negative tumors (basal-like and normal breast-like). A proportion of BC cases are of the triple-negative breast cancer (TNBC) type. TNBC lacks the expression of estrogen receptor (ER), progesterone receptor (PR), and HER-2, and is known to express androgen receptor (AR) at considerable levels. AR has been shown to promote the progression of TNBC. However, the exact mechanisms have yet to be unraveled. One of these mechanisms could be through regulating the expression of microRNA (miRNA) molecules, which play an important regulatory role in BC through post-transcriptional gene silencing. Activation of AR controls the expression of miRNA molecules, which target selective mRNAs, consequently, affecting protein expression. In this review we attempt to elucidate the relations between AR and miRNA in TNBC.

Molecular Origin, Expression Regulation, and Biological Function of Androgen Receptor Splicing Variant 7 in Prostate Cancer

The problem of resistance to therapy in prostate cancer (PCa) is multifaceted. Key determinants of drug resistance include tumor burden and growth kinetics, tumor heterogeneity, physical barriers, immune system and microenvironment, undruggable cancer drivers, and consequences of therapeutic pressures. With regard to the fundamental importance of the androgen receptor (AR) in all stages of PCa from tumorigenesis to progression, AR is postulated to have a continued critical role in castration-resistant prostate cancer (CRPC). Suppression of AR signaling mediated by the full-length AR (AR-FL) is the therapeutic goal of all AR-directed therapies. However, AR-targeting agents ultimately lead to AR aberrations that promote PCa progression and drug resistance. Among these AR aberrations, androgen receptor variant 7 (AR-V7) is gaining attention as a potential predictive marker for as well as one of the resistance mechanisms to the most current anti-AR therapies in CRPC. Meanwhile, development of next-generation drugs that directly or indirectly target AR-V7 signaling is urgently needed. In the present review of the current literature, we have summarized the origin, alternative splicing, expression induction, protein conformation, interaction with coregulators, relationship with AR-FL, transcriptional activity, and biological function of AR-V7 in PCa development and therapeutic resistance. We hope this review will help further understand the molecular origin, expression regulation, and role of AR-V7 in the progression of PCa and provide insight into the design of novel selective inhibitors of AR-V7 in PCa treatment.

Two cases of gonad retention in adolescent patients with complete androgen insensitivity syndrome (CAIS)

Bilateral gonadectomy was the historical recommendation for patients diagnosed with complete androgen insensitivity syndrome (CAIS) due to the perceived risk of malignancy in the gonads. However, new shared-decision making approaches are allowing patients to explore the option to defer surgery. Here we report two patients who presented with primary amenorrhea to their primary care provider (PCP). After imaging and karyotyping, these patients were diagnosed with CAIS. They underwent exams under anesthesia and diagnostic laparoscopies in which the gonads did not present any immediate concerns or indications for removal. After discussing their options using the shared-decision making approach with the differences in sex development (DSD) team, they opted to defer gonadectomy and follow up annually with imaging to monitor the gonads.

A Crucial Role for the Protein Quality Control System in Motor Neuron Diseases

Motor neuron diseases (MNDs) are fatal diseases characterized by loss of motor neurons in the brain cortex, in the bulbar region, and/or in the anterior horns of the spinal cord. While generally sporadic, inherited forms linked to mutant genes encoding altered RNA/protein products have also been described. Several different mechanisms have been found altered or dysfunctional in MNDs, like the protein quality control (PQC) system. In this review, we will discuss how the PQC system is affected in two MNDs—spinal and bulbar muscular atrophy (SBMA) and amyotrophic lateral sclerosis (ALS)—and how this affects the clearance of aberrantly folded proteins, which accumulate in motor neurons, inducing dysfunctions and their death. In addition, we will discuss how the PQC system can be targeted to restore proper cell function, enhancing the survival of affected cells in MNDs.

Evolution of the androgen receptor: Perspectives from human health to dancing birds

Androgenic hormones orchestrate the development and activation of diverse reproductive phenotypes across vertebrates. Although extensive work investigates how selection for these traits modifies individual elements of this signaling system (e.g., hormone or androgen receptor [AR] levels), we know less about natural variation in the AR sequence across vertebrates. Our knowledge of AR sequence mutations is largely limited to work in human patients or cell-lines, providing a framework to contextualize single mutations at the expense of evolutionary timescale. Here we unite both perspectives in a review that explores the functional significance of AR on a domain-by-domain basis, using existing knowledge to highlight how and why each region might evolve. We then examine AR sequence variation on different timescales by examining sequence variation in clades originating in the Cambrian (vertebrates; >500 mya) and Cretaceous (birds; >65 mya). In each case, we characterize how the receptor has changed over time and discuss which regions are most likely to evolve in response to selection. Overall, domains that are required for androgenic signaling to function (e.g., DNA- and ligand-binding) tend to be conserved. Meanwhile, areas that interface with co-regulatory molecules can exhibit notable variation even between closely related species. We propose that accumulating mutations in regulatory regions is one way that AR structure might act as a substrate for selection to guide the evolution of reproductive traits. By synthesizing literature across disciplines and highlighting the evolutionary potential of specific AR regions, we hope to inspire new avenues of integrative research into endocrine system evolution.

The X chromosome and male infertility

The X chromosome is a key player in germ cell development, as has been highlighted for males in previous studies revealing that the mammalian X chromosome is enriched in genes expressed in early spermatogenesis. In this review, we focus on the X chromosome’s unique biology as associated with human male infertility. Male infertility is most commonly caused by spermatogenic defects to which X chromosome dosage is closely linked; for example, any supernumerary X chromosome as in Klinefelter syndrome will lead to male infertility. Furthermore, because males normally only have a single X chromosome and because X-linked genetic anomalies are generally only present in a single copy in males, any loss-of-function mutations in single-copy X-chromosomal genes cannot be compensated by a normal allele. These features make X-linked genes particularly attractive for studying male spermatogenic failure. However, to date, only very few genetic causes have been identified as being definitively responsible for male infertility in humans. Although genetic studies of germ cell-enriched X-chromosomal genes in mice suggest a role of certain human orthologs in infertile men, these genes in mice and humans have striking evolutionary differences. Furthermore, the complexity and highly repetitive structure of the X chromosome hinder the mutational analysis of X-linked genes in humans. Therefore, we conclude that additional methodological approaches are urgently warranted to advance our understanding of the genetics of X-linked male infertility.

Molecular Mechanisms and Therapeutics for SBMA/Kennedy's Disease

Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disease caused by a polyglutamine (polyQ) expansion in the androgen receptor (AR). Despite the fact that the monogenic cause of SBMA has been known for nearly 3 decades, there is no effective treatment for this disease, underscoring the complexity of the pathogenic mechanisms that lead to a loss of motor neurons and muscle in SBMA patients. In the current review, we provide an overview of the system-wide clinical features of SBMA, summarize the structure and function of the AR, discuss both gain-of-function and loss-of-function mechanisms of toxicity caused by polyQ-expanded AR, and describe the cell and animal models utilized in the study of SBMA. Additionally, we summarize previously conducted clinical trials which, despite being based on positive results from preclinical studies, proved to be largely ineffective in the treatment of SBMA; nonetheless, these studies provide important insights as researchers develop the next generation of therapies.

A shared decision-making tool for individuals living with complete androgen insensitivity syndrome

Reports exist regarding a gradual approach to the care of patients with differences of sexual development. Each patient and family have different values and styles of learning that have to be taken into account. The goals of care should include education about the condition, counseling of the patient and family, and a complete outlining of treatment options. Motivated by a call from the 2010 Health Reform Law for the use of shared decision-making tools and the emphasis placed on these issues by the DSD Consensus Statement, we sought to develop and implement such tools for the DSD population.^1-3 Thus, we developed an organized checklist for providers to share with a patients and families affected by CAIS, beginning with the initial visit. The development of the document enlisted input from physicians, clinical coordinator, advocacy groups and affected individuals. It allows providers to explain the process of care and develop a plan for delivery of that care over multiple visits spanning six months or more. The checklist is divided into five sections: 1) An overview addressing how much information is desired and in what manner the patient prefers to obtain information; 2) A preferred words list so that the patient can choose nomenclature that is most comfortable; 3) A list of topics to review over the course of multiple visits; 4) A list of questions to be answered by the providers or other resources over time, and; 5) A list of concerns to be addressed before surgical intervention is considered. An organized approach to long-term delivery of compassionate care and accurate information can be facilitated for patients with CAIS by the use of a shared decision-making checklist. Documentation of the care delivery process can stimulate referral to peer support and promote fully informed consent for treatment decisions. The use of the checklist should encourage trust in the provider, as well as aid in identifying and addressing stressors for the patient and family. The checklist will be updated and revised as new treatments and advanced technology emerges.

Androgen Insensitivity Syndrome: Clinical Phenotype and Molecular Analysis in a Single Tertiary Center Cohort

OBJECTIVE

The aim of this study was the molecular characterization of the AR gene as the cause of 46,XY disorder in our population.

METHODS

We studied 41, non related, 46,XY disorder of sexual differentiation index cases, having characteristics consistent with androgen insensivity syndrome (AIS). Genomic DNA was isolated from peripheral blood leukocytes of all patients and 25 family members from 17 non-related families.

RESULTS

The AR gene analysis revealed an abnormal sequence in 58.5% of the index patients. All of the complete AIS (CAIS) cases were genetically confirmed, while in the partial form (PAIS) a mutation in AR was detected in only 13 (43.3%). Molecular studies revealed other affected or carrier relatives in 87% of the index cases. The AR mutations were found spread along the whole coding sequence, with a higher prevalence in the ligand binding domain. Nine out of 23 (39%) AR mutations were novel. In 17% of patients with detected AR mutations, somatic mosaicism was detected in leucocyte DNA. In our cohort, long-term follow up gender dysphoria, raised as male or female, was not found. Finally, in suspected PAIS, the identification of AR mutation occurred significantly less than in CAIS patients.

CONCLUSION

Improved knowledge of the components of the AR complex and signaling network might contribute to long term outcome and genetic counseling in AIS patients.

Impaired Nuclear Export of Polyglutamine-Expanded Androgen Receptor in Spinal and Bulbar Muscular Atrophy

Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disease caused by polyglutamine (polyQ) expansion in the androgen receptor (AR). Prior studies have highlighted the importance of AR nuclear localization in SBMA pathogenesis; therefore, in this study, we sought to determine the role of AR nuclear export in the pathological manifestations of SBMA. We demonstrate here that the nuclear export of polyQ-expanded AR is impaired, even prior to the formation of intranuclear inclusions of aggregated AR. Additionally, we find that promoting AR export with an exogenous nuclear export signal substantially reduces its aggregation and blocks hormone-induced toxicity. Moreover, we show that these protective effects are conferred by destabilization of the mutant protein due to an increase in proteasomal degradation of the cytoplasmic AR. Despite a growing body of evidence that global disruption of nucleo/cytoplasmic transport occurs in ALS and HD, our data suggest that no such global disruption occurs in models of SBMA; rather, AR-specific mechanisms, including reduced phosphorylation at Serine 650, are likely responsible for the impaired nuclear export of polyQ-expanded AR.

Ambiguous genitalia: An overview of 7 years experience at the Children's Hospital & Institute of Child Health, Lahore, Pakistan

Objective:

To determine the classification and etiological diagnosis of children presented with ambiguous genitalia/atypical genitalia according to the newer classification system of Disorder of Sex Development (DSD).

Methods:

This observational, cross-sectional study was conducted at the Department of Pediatric Endocrinology and Diabetes at The Children’s Hospital &Institute of Child Health, Lahore from January, 2007 to December; 2014. Files of all the children with ambiguous genitalia were retrospectively analyzed and relevant data was retrieved. All the information was recorded on predesigned proforma and analyzed accordingly.

Results:

A total of 300 cases of ambiguous genitalia classified according to the new DSD classification. 46, XX DSD were 54.3% (n=163), 46, XY DSD were 43.7% (n=131), sex chromosome DSD were 2% (n=6). Among 46, XX DSD cases, the most common cause was congenital adrenal hyperplasia (97%, n=158). However, in 46, XY DSD partial androgen insensitivity/5α-reductase deficiency (62%. n=81) constituted the most commonest disorder. Other causes of 46XY DSD include testosterone synthesis defect(23%), congenital adrenal hyperplasia (CAH,12%), testis regression syndrome (1.5%) and persistent mullerian duct syndrome (PMDS,1.5%). Sex chromosome disorder constituted one case of iso-chromosome X turner syndrome, mixed gonadal dysgenesis (n=3), ovotesticular DSD/chimerism (n=2).

Conclusion:

Ambiguous genitalia have varied etiologies, 46; XXDSD found being the commonest of all, showing predominance of CAH especially salt loosing type. The early detection and prompt treatment of cases of ambiguous genitalia plays a pivotal role in the management of acute life threatening condition and gender assignment.

Partial androgen insensitivity syndrome presenting as pubertal gynecomastia: clinical and hormonal findings and a novel mutation in the androgen receptor gene

Pubertal gynecomastia is common, can be seen in 65% of the adolescent boys and is considered physiological. It is thought to be due to transient imbalance between the ratio of testosterone and estradiol in the early stages of puberty. It resolves in 1-2 years and requires no treatment. However, more persistent and severe pubertal gynecomastia is less common and can be associated with pathological disorders. These can be due to diminished androgen production, increased estrogen production or androgen resistance. We report a case of persistent pubertal gynecomastia due to partial androgen insensitivity syndrome (PAIS), classical hormone findings and a novel mutation in the androgen receptor (AR) gene. Learning points: Laboratory testing of follicle-stimulating hormone (FSH), leutinizing hormone (LH) and testosterone for pubertal gynecomastia is most helpful in the setting of undervirization. The hormonal finding of very high testosterone, elevated LH and estradiol and relatively normal FSH are classical findings of PAIS. Gynecomastia due to PAIS will not resolve and surgery for breast reduction should be recommended.

Molecular diagnostics of disorders of sexual development: an Indian survey and systems biology perspective

We aimed to survey the monogenic causes of disorders of sex development (DSD) and thereby its prevalence in India. This study revealed mutations resulting in androgen insensitivity syndrome, 5α-reductase type 2 deficiency, and gonadal dysgenesis were commonly reported. Intriguingly, AR deficits were the most prevalent (32 mutations) and of 11/26 missense mutations were in exons 4-8 (encoding ligand binding domain). The unique features of SRD5A2 defects were p.R246Q (most prevalent) and p.G196S could be mutational hotspots, dual gene defects (p.A596T in AR and p.G196S in SRD5A2) in a patient with hypospadias and novel 8 nucleotide deletion (exon 1) found in a patient with perineal hypospadias. Deficits in SRY, WT1, DHH, NR5A1, and DMRT1 caused 46,XY gonadal dysgenesis. Notably, mutations in AR, SRD5A2, MAMLD1, WT1, and MAP3K1 have led to hypospadias and only one CYP19A1 mutation caused aromatase deficiency was reported to date. Data mining from various databases has not only reinforced the role of well-established genes (e.g., SRY, WT1, DHH, NR5A1, DMRT1, AR, SRD5A2, MAMLD1) involved in DSD but also provided us 12 more potential candidate genes (ACVR1, AMHR2, CTNNB1, CYP11A1, CYP19A1, FGFR2, FGF9, PRKACA, PRKACG, SMAD9, TERT, ZFPM2), which benefit from a close association with the well-established genes involved in DSD and might be useful to screen owing to their direct gene-phenotype relationship or through direct functional interaction. As more genes have been revealed in relation to DSD, we believe ultimately it holds a better scenario for therapeutic regimen. Despite the advances in translational medicine, hospitals are yet to adopt genetic testing and counseling facilities in India that shall have potential impact on clinical diagnosis. Abbreviations: 5α-RD2: 5α-Reductase type 2; AIS: androgen insensitivity syndrome; AMH: antimullerian hormone; AMHR: antimullerian hormone receptor; AR: androgen receptor gene; CAH: congenital adrenal hyperplasia; CAIS: complete AIS; CAH: congenital adrenal hyperplasia; CHH: congenital hypogonadotropic hypogonadism; CXORF6: chromosome X open reading frame 6 gene; CYP19A1: cytochrome P450 family 19 subfamily A member 1 gene; DHT: dihydrotestosterone; DMRT1: double sex and mab-3 related transcription factor 1 gene; DSD: disorders of sexual development; GD: gonadal dysgenesis; HGMD: human gene mutation database; IH: isolated hypospadias; MAMLD1: mastermind like domain containing 1 gene; MIS: mullerian inhibiting substance; NTD: N-terminal domain; OT DSD: ovotesticular DSD; PAIS: partial AIS; SOX9: SRY-related HMG-box 9 gene; SRY: sex-determining region Y gene; STAR: steroidogenic acute regulatory protein gene; SRD5A2: steroid 5 alpha-reductase 2 gene; T DSD: testicular DSD; T: testosterone; WNT4: Wnt family member 4 gene; WT1: Wilms tumor 1 gene; Δ₄: androstenedione.

Two Korean girls with complete androgen insensitivity syndrome diagnosed in infancy

Androgen insensitivity syndrome (AIS) is a rare genetic disease caused by various abnormalities in the androgen receptor (AR). The AR is an essential steroid hormone receptor that plays a critical role in male sexual differentiation and development and preservation of the male phenotype. Mutations in the AR gene on the X chromosome cause malfunction of the AR so that a 46,XY karyotype male has some physical characteristics of a woman or a full female phenotype. Depending on the phenotype, AIS can be classified as complete, partial or mild. Here, we report 2 cases of complete AIS in young children who showed complete sex reversal from male to female as a result of AR mutations. They had palpable inguinal masses and normal female external genitalia, a blind-end vagina and absent Müllerian duct derivatives. They were both 46,XY karyotype and AR gene analysis demonstrated pathologic mutations in both. Because AIS is inherited in an X-linked recessive manner, we performed genetic analysis of the female family members of each patient and found the same mutation in the mothers of both patients and in the female sibling of case 2. Gonadectomy was performed in both patients to avoid the risk of malignancy in the undescended testicles, and estrogen replacement therapy is planned for their adolescence. Individuals with complete AIS are usually raised as females and need appropriate care.

Complete Androgen Insensitivity Syndrome due to Mutations in the DNA-Binding Domain of the Human Androgen Receptor Gene

Androgen insensitivity syndrome (AIS) is an X-linked recessive disorder with a 46,XY karyotype caused by alterations in the androgen receptor (AR) gene. We have identified 2 mutations in the AR gene that resulted in complete androgen insensitivity syndrome (CAIS) in 2 unrelated cases. This study includes cytogenetics, hormonal, molecular, and bioinformatics analysis including sequencing of the SRY (sex-determining region Y) and AR genes. Mutational analysis in the first case of primary amenorrhea revealed a novel nucleotide substitution (IVS2-2A>G) in the second intron of the AR gene. The mutation is located in the acceptor splice site (2 nucleotides before exon 3) and caused skipping of exon 3 and formation of an abnormal protein. The second mutation (g. 98762_98764delTCT) was identified in a case of oligoamenorrhea and caused the deletion of 1 amino acid (p.∆Phe583). Both identified mutations were located in the conserved P-box region of the DNA-binding domain which is responsible for base-specific contacts with the DNA major groove. Furthermore, a hormonal imbalance was also noticed in both cases with high levels of gonadotropins like FSH and LH in both cases. The present study concluded that both identified AR mutations are predicted to either abolish or decrease the binding ability of the AR to androgen response elements of its downstream genes.

Beyond motor neurons: expanding the clinical spectrum in Kennedy's disease

Kennedy's disease, or spinal and bulbar muscular atrophy (SBMA), is an X-linked neuromuscular condition clinically characterised by weakness, atrophy and fasciculations of the limb and bulbar muscles, as a result of lower motor neuron degeneration. The disease is caused by an abnormally expanded triplet repeat expansions in the ubiquitously expressed androgen receptor gene, through mechanisms which are not entirely elucidated. Over the years studies from both humans and animal models have highlighted the involvement of cell populations other than motor neurons in SBMA, widening the disease phenotype. The most compelling aspect of these findings is their potential for therapeutic impact: muscle, for example, which is primarily affected in the disease, has been recently shown to represent a valid alternative target for therapy to motor neurons. In this review, we discuss the emerging study of the extra-motor neuron involvement in SBMA, which, besides increasingly pointing towards a multidisciplinary approach for affected patients, deepens our understanding of the pathogenic mechanisms and holds potential for providing new therapeutic targets for this disease.

Post-finasteride syndrome and post-SSRI sexual dysfunction: two sides of the same coin?

Sexual dysfunction is a clinical condition due to different causes including the iatrogenic origin. For instance, it is well known that sexual dysfunction may occur in patients treated with antidepressants like selective serotonin reuptake inhibitors (SSRI). A similar side effect has been also reported during treatment with finasteride, an inhibitor of the enzyme 5alpha-reductase, for androgenetic alopecia. Interestingly, sexual dysfunction persists in both cases after drug discontinuation. These conditions have been named post-SSRI sexual dysfunction (PSSD) and post-finasteride syndrome (PFS). In particular, feeling of a lack of connection between the brain and penis, loss of libido and sex drive, difficulty in achieving an erection and genital paresthesia have been reported by patients of both conditions. It is interesting to note that the incidence of these diseases is probably so far underestimated and their etiopathogenesis is not sufficiently explored. To this aim, the present review will report the state of art of these two different pathologies and discuss, on the basis of the role exerted by three different neuromodulators such as dopamine, serotonin and neuroactive steroids, whether the persistent sexual dysfunction observed could be determined by common mechanisms.

Peripheral sensitivity to steroids revisited

Resistance to steroid hormones presents a serious problem with respect to their mass use in therapy. It may be caused genetically by mutation of genes involved in hormonal signaling, not only steroid receptors, but also other players in the signaling cascade as co-regulators and other nuclear factors, mediating the hormone-born signal. Another possibility is acquired resistance which may develop under long-term steroid treatment, of which a particular case is down regulation of the receptors. In the review recent knowledge is summarized on the mechanism of main steroid hormone action, pointing to already proven or potential sites causing steroid resistance. We have attempted to address following questions: 1) What does stay behind differences among patients as to their response to the (anti)steroid treatment? 2) Why do various tissues/cells respond differently to the same steroid hormone though they contain the same receptors? 3) Are such differences genetically dependent? The main attention was devoted to glucocorticoids as the most frequently used steroid therapeutics. Further, androgen insensitivity is discussed with a particular attention to acquired resistance to androgen deprivation therapy of prostate cancer. Finally the potential causes are outlined of breast and related cancer(s) resistance to antiestrogen therapy.

Gonadoblastoma in Androgen Insensitivity Syndrome A Case Report

We report a case of androgen insensitivity syndrome (AIS) characterized by malignant degeneration of the testes consisting of gonadoblastoma and dysgerminoma. AIS is a rare inherited form of male pseudohermaphroditism that can manifest as a normal female phenotype without müllerian derivatives and absence of the upper third of the vagina. A 32-year-old white 46,XY female with AIS underwent removal of the dysgenetic gonads at the Gynecological Oncology Department of the Istituto Nazionale Tumori, Milan, Italy. We investigated cytogenetic alterations, hormonal levels and the presence of neoplasia in the dysgenetic gonads. Histological analysis revealed a gonadoblastoma mixed with dysgerminoma in the left gonad and a pure dysgerminoma in the right gonad. The patient's hormonal status matched that of a male. Second-look laparotomy after chemotherapy showed a complete pathological response.

AIS should be suspected in phenotypically female patients with primary amenorrhea; surgical removal of the gonads is mandatory to avoid malignant degeneration.

Population Pharmacokinetic/Pharmacodynamic Modeling of Depot Testosterone Cypionate in Healthy Male Subjects

A randomized, double‐blind clinical trial was conducted to investigate long‐term abuse effects of testosterone cypionate (TC). Thirty‐one healthy men were randomized into a dose group of 100, 250, or 500 mg/wk and received 14 weekly injections of TC. A pharmacokinetic/pharmacodynamic (PK/PD) model was developed to characterize testosterone concentrations and link exposure to change in luteinizing hormone and spermatogenesis following long‐term TC administration. A linear one‐compartment model best described the concentration‐time profile of total testosterone. The population mean estimates for testosterone were 2.6 kL/day for clearance and 14.4 kL for volume of distribution. Weight, albumin, and their changes from baseline were identified as significant covariates for testosterone. The estimated potency of total testosterone (tT) with respect to suppression of luteinizing hormone (LH) synthesis was 9.33 ng/mL. Simulation based on the indirect response model suggests the suppression of endogenous testosterone secretion, LH synthesis, and spermatogenesis was more severe and of greater duration in the 250 mg and the 500 mg dose groups.

MECHANISMS IN ENDOCRINOLOGY: Aberrations of the X chromosome as cause of male infertility

Male infertility is most commonly caused by spermatogenetic failure, clinically noted as oligo- or a-zoospermia. Today, in approximately 20% of azoospermic patients, a causal genetic defect can be identified. The most frequent genetic causes of azoospermia (or severe oligozoospermia) are Klinefelter syndrome (47,XXY), structural chromosomal abnormalities and Y-chromosomal microdeletions. Consistent with Ohno's law, the human X chromosome is the most stable of all the chromosomes, but contrary to Ohno's law, the X chromosome is loaded with regions of acquired, rapidly evolving genes, which are of special interest because they are predominantly expressed in the testis. Therefore, it is not surprising that the X chromosome, considered as the female counterpart of the male-associated Y chromosome, may actually play an essential role in male infertility and sperm production. This is supported by the recent description of a significantly increased copy number variation (CNV) burden on both sex chromosomes in infertile men and point mutations in X-chromosomal genes responsible for male infertility. Thus, the X chromosome seems to be frequently affected in infertile male patients. Four principal X-chromosomal aberrations have been identified so far: (1) aneuploidy of the X chromosome as found in Klinefelter syndrome (47,XXY or mosaicism for additional X chromosomes). (2) Translocations involving the X chromosome, e.g. nonsyndromic 46,XX testicular disorders of sex development (XX-male syndrome) or X-autosome translocations. (3) CNVs affecting the X chromosome. (4) Point mutations disrupting X-chromosomal genes. All these are reviewed herein and assessed concerning their importance for the clinical routine diagnostic workup of the infertile male as well as their potential to shape research on spermatogenic failure in the next years.

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.

Mild androgen insensitivity syndrome (MAIS): the identification of c.1783C>T mutation in two unrelated infertile men

Two unrelated men complaining of primary male infertility presented to Orient Hospital in Damascus city. Physical examination showed moderate hypoandrogenic features. Both men were azoospermic. Hormone profiles revealed an elevation of follicle-stimulating hormone in one patient, but all the other hormones tested were within normal limits for both patients. Further genetic analyses, including karyotype and microdeletions in the AZF region of the Y chromosome, were normal in both patients. Mild androgen insensitivity syndrome was expected in the two patients. Sequencing analysis of the first exon in the androgen receptor (AR) gene have shown c.1783C>T mutation in the two patients with azoospermia. This paper sheds light on the need to screen for mutations in the AR gene, causing male infertility whenever mild hypoandrogenic features are present with unexplained male infertility.

The Long-Term Outcome of Boys With Partial Androgen Insensitivity Syndrome and a Mutation in the Androgen Receptor Gene

BACKGROUND

In boys with suspected partial androgen insensitivity syndrome (PAIS), systematic evidence that supports the long-term prognostic value of identifying a mutation in the androgen receptor gene (AR) is lacking.

OBJECTIVE

To assess the clinical characteristics and long-term outcomes in young men with suspected PAIS in relation to the results of AR analysis.

METHODS

Through the International Disorders of Sex Development Registry, clinical information was gathered on young men suspected of having PAIS (n = 52) who presented before the age of 16 years and had genetic analysis of AR.

RESULTS

The median ages at presentation and at the time of the study were 1 month (range, 1 day to 16 years) and 22 years (range, 16 to 52 years), respectively. Of the cohort, 29 men (56%) had 20 different AR mutations reported. At diagnosis, the median external masculinization scores were 7 and 6 in cases with and without AR mutation, respectively (P = .9), and median current external masculinization scores were 9 and 10, respectively (P = .28). Thirty-five men (67%) required at least one surgical procedure, and those with a mutation were more likely to require multiple surgeries for hypospadias (P = .004). All cases with an AR mutation had gynecomastia, compared to 9% of those without an AR mutation. Of the six men who had a mastectomy, five (83%) had an AR mutation.

CONCLUSIONS

Boys with genetically confirmed PAIS are likely to have a poorer clinical outcome than those with XY DSD, with normal T synthesis, and without an identifiable AR mutation. Routine genetic analysis of AR to confirm PAIS informs long-term prognosis and management.

Structures of androgen receptor bound with ligands: advancing understanding of biological functions and drug discovery

INTRODUCTION

Androgen receptor (AR) is a ligand-dependent transcription factor and a member of the nuclear receptor superfamily. It plays a vital role in male sexual development and regulates gene expression in various tissues, including prostate. Androgens are compounds that exert their biological effects via interaction with AR. Binding of androgens to AR initiates conformational changes in AR that affect binding of co-regulator proteins and DNA. AR agonists and antagonists are widely used in a variety of clinical applications (i.e. hypogonadism and prostate cancer therapy).

AREAS COVERED

This review provides a close look at structures of AR-ligand complexes and mutations in the receptor that have been revealed, discusses current challenges in the field, and sheds light on future directions.

EXPERT OPINION

AR is one of the primary targets for the treatment of prostate cancer, as AR antagonists inhibit prostate cancer growth. However, these drugs are not effective for long-term treatment and lead to castration-resistant prostate cancer. The structures of AR-ligand complexes are an invaluable scientific asset that enhances our understanding of biological functions and mechanisms of androgenic and anti-androgenic chemicals as well as promotes the discovery of superior drug candidates.

Impact of CAG repeat length in the androgen receptor gene on male infertility - a meta-analysis

CAG repeats are polymorphic nucleotide repeats present in the androgen receptor gene. Many studies have estimated the association between CAG repeat length and male infertility, but the conclusions are controversial. Previous meta-analyses have come to different conclusions; however, new studies have been published. An updated meta-analysis was conducted. PubMed, CBM, CNKI and Web of Science databases were systematically searched for studies published from 1 January 2000 to 1 October 2015. Case-control studies on the association between CAG repeat length and male infertility using appropriate methodology were included. Forty studies were selected, including 3858 cases and 3161 controls. Results showed statistically significantly longer CAG repeat length among cases compared with controls (SMD = 0.14; 95% CI, 0.02-0.26). Shorter repeat length was associated with a lower risk of male infertility compared with a longer repeat length in the overall analysis (OR = 0.79, 95% CI: 0.66-0.95). Moreover, CAG repeat length was associated with male infertility in Caucasian populations, but not Asian or Egyptian populations. Subgroup analysis revealed no significant difference in German populations, but CAG repeat length was associated with male infertility in China and the USA. There were no significant differences between cases and controls in azoospermia and severe oligozoospermia.

Mutational analysis of the androgen receptor gene in two Chinese families with complete androgen insensitivity syndrome

Androgens are essential for normal male sex differentiation and are responsible for the normal development of male secondary sexual characteristics at puberty. The physiological effects of androgens are mediated by the androgen receptor (AR). Mutations in the AR gene are the most common cause of androgen insensitivity syndrome. The present study undertook a genetic analysis of the AR gene in two unrelated families affected by complete androgen insensitivity syndrome (CAIS) in China. In family 1, a previously reported nonsense mutation (G-to-A; p.W751X) was identified in exon 5 of the AR gene. In addition, a novel missense mutation was detected in exon 6 of the AR gene from family 2; this mutation resulted in a predicted amino acid change from phenylalanine to serine at codon 804 (T-to-C; p.F804S) in the ligand-binding domain (LBD) of AR. Computer simulation of the structural changes generated by the p.F804S substitution revealed marked conformational alterations in the hydrophobic core responsible for the stability and function of the AR-LBD. In conclusion, the present study identified two mutations from two unrelated Chinese families affected by CAIS. The novel mutation (p.F804S) may provide insights into the molecular mechanism underlying CAIS. Furthermore, it expands on the number of mutational hot spots in the international AR mutation database, which may be useful in the future for prenatal diagnosis and genetic counseling.

Male Pattern Baldness in Relation to Prostate Cancer-Specific Mortality: A Prospective Analysis in the NHANES I Epidemiologic Follow-up Study

We used male pattern baldness as a proxy for long-term androgen exposure and investigated the association of dermatologist-assessed hair loss with prostate cancer-specific mortality in the first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. From the baseline survey (1971-1974), we included 4,316 men who were 25-74 years of age and had no prior cancer diagnosis. We estimated hazard ratios and used Cox proportional hazards regressions with age as the time metric and baseline hazard stratified by baseline age. A hybrid framework was used to account for stratification and clustering of the sample design, with adjustment for the variables used to calculate sample weights. During follow-up (median, 21 years), 3,284 deaths occurred; prostate cancer was the underlying cause of 107. In multivariable models, compared with no balding, any baldness was associated with a 56% higher risk of fatal prostate cancer (hazard ratio = 1.56; 95% confidence interval: 1.02, 2.37), and moderate balding specifically was associated with an 83% higher risk (hazard ratio = 1.83; 95% confidence interval: 1.15, 2.92). Conversely, patterned hair loss was not statistically significantly associated with all-cause mortality. Our analysis suggests that patterned hair loss is associated with a higher risk of fatal prostate cancer and supports the hypothesis of overlapping pathophysiological mechanisms.

Preventing the Androgen Receptor N/C Interaction Delays Disease Onset in a Mouse Model of SBMA

Spinal and bulbar muscular atrophy (SBMA) is a neurodegenerative disease caused by a polyglutamine expansion in the androgen receptor (AR) and is associated with misfolding and aggregation of the mutant AR. We investigated the role of an interdomain interaction between the amino (N)-terminal FxxLF motif and carboxyl (C)-terminal AF-2 domain in a mouse model of SBMA. Male transgenic mice expressing polyQ-expanded AR with a mutation in the FxxLF motif (F23A) to prevent the N/C interaction displayed substantially improved motor function compared with N/C-intact AR-expressing mice and showed reduced pathological features of SBMA. Serine 16 phosphorylation was substantially enhanced by the F23A mutation; moreover, the protective effect of AR F23A was dependent on this phosphorylation. These results reveal an important role for the N/C interaction on disease onset in mice and suggest that targeting AR conformation could be a therapeutic strategy for patients with SBMA.

Towards a non-animal risk assessment for anti-androgenic effects in humans

Toxicology testing is undergoing a transformation from a system based on high-dose studies in laboratory animals to one founded primarily on in vitro methods that evaluate changes in normal cellular signalling pathways using human-relevant cells or tissues. We review the tools and approaches that could be used to develop a non-animal safety assessment for anti-androgenic effects in humans, with a focus on the molecular initiating events (MIEs) that human disorders indicate critical for normal functioning of the hypothalamus-pituitary-testicular (HPT) axis. In vitro test systems exist which can be used to characterize the effects of test chemicals on some MIEs such as androgen receptor antagonism, inhibition of steroidogenic enzymes or 5α-reductase inhibition. When used alongside information describing the pharmacokinetics of a specific chemical exposure, these could be used to inform a pathways-based safety assessment. However, some parts of the HPT axis such as events occurring in the hypothalamus or pituitary are not well represented by accepted in vitro methods. In vitro tools to characterize perturbations in these events need to be developed before a fully integrated model of the HPT axis can be described. Knowledge gaps also exist which prevent us from using in vitro data to predict the type and severity of in vivo effect(s) that could arise from a given level of in vitro anti-androgenic activity. This means that more work is needed to reliably link an MIE with an adverse outcome. However, especially for chemicals with low anti-androgenic activity, human exposure data can be used to put in vitro mode of action data into context for risk-based safety decision-making.

Preserved fertility in a patient with gynecomastia associated with the p.Pro695Ser mutation in the androgen receptor

The androgen insensitivity syndrome (AIS) is described as a dysfunction of the androgen receptor (AR) in 46,XY individuals, which can be associated with mutations in the AR gene or can be due to unknown mechanisms. Different mutations in AIS generally cause variable phenotypes that range from a complete hormone resistance to a mild form usually associated with male infertility. The purpose of this study was to search for mutations in the AR gene in a fertile man with gynecomastia and to evaluate the influence of the mutation on the AR transactivation ability. Sequencing of the AR gene revealed the p.Pro695Ser mutation. It is located within the AR ligand-binding domain. Bioinformatics analysis indicated a deleterious role, which was verified after testing transactivation activity and N-/C-terminal (N/C) interaction by in vitro expression of a reporter gene and 2-hybrid assays. p.Pro695Ser showed low levels of both transactivation activity and N/C interaction at low dihydrotestosterone (DHT) conditions. As the ligand concentration increased, both transactivation activity and N/C interaction also increased and reached normal levels. Therefore, this study provides functional insights for the p.Pro695Ser mutation described here for the first time in a patient with mild AIS. The expression profile of p.Pro695Ser not only correlates to the patient's phenotype, but also suggests that a high-dose DHT therapy may overcome the functional deficit of the mutant AR.

Involvement of the Androgen and Glucocorticoid Receptors in Bladder Cancer

Bladder cancer is encountered worldwide having been associated with a host of environmental and lifestyle risk factors. The disease has a male to female prevalence of 3 : 1. This disparity has raised the possibility of the androgen receptor (AR) pathway being involved in the genesis of the disease; indeed, research has shown that AR is involved in and is likely a driver of bladder cancer. Similarly, an inflammatory response has been implicated as a major player in bladder carcinogenesis. Consistent with this concept, recent work on anti-inflammatory glucocorticoid signaling points to a pathway that may impact bladder cancer. The glucocorticoid receptor- (GR-) α isoform has an important role in suppressing inflammatory processes, which may be attenuated by AR in the development of bladder cancer. In addition, a GR isoform that is inhibitory to GRα, GRβ, is proinflammatory and has been shown to induce cancer growth. In this paper, we review the evidence of inflammatory mediators and the relationship of AR and GR isoforms as they relate to the propensity for bladder cancer.