Androgen Receptor Gene Research Articles

Structural and molecular insights into the mechanism of resistance to enzalutamide by the clinical mutants in androgen receptor (AR) in castration-resistant prostate cancer (CRPC) patients

Androgen receptor (AR) is a key contributing element in the prostate cancer (PCa) instigation, progression and it is among the vastly discovered target for prostate cancer. Numerous mechanisms trigger the expansion of CRPC among which the aberrant AR gene is considered as the prime factor. Recently three essential substitutions H875Y, F877L, and T878A are reported to cause resistance to Enzalutamide. However, no detailed study is available to explore the key events that contribute to the resistance. Hence, considering the applicability of structural bioinformatics and molecular simulation-based methods in the current study, we assessed the impact of these mutations on the binding of Enzalutamide. Using a long-run simulation approach the binding stability, residues flexibility, hydrogen bonding, and protein compactness for each complex were determined to reveal the dynamic variations induced by these mutations. We discovered that the binding mode of Enzalutamide is altered by these mutations which misstarget the key residues required for the antagonistic activity. Molecular simulation of each complex revealed that the wild type H11 and H12 are more flexible moving outside and provides more volume for the ligand optimization. In the mutant complexes, the H12 remained tighter pushing out enzalutamide from the key residues which then essentially misstarget the correct orientation for the antagonist activity. The binding free energy (BFE) for the wild type was computed to be −59.92 ± 0.18 kcal/mol, for H875Y the BFE was −55.92 ± 0.18 kcal/mol, −54.82 ± 0.15 kcal/mol for F877L and −53.87 ± 0.18 kcal/mol for T878A, which further demonstrate that these mutations have destabilized the binding of enzalutamide. The proteins' motion and FEL further validated the aforementioned findings where the wild type reported different dynamic features than the mutant complexes. In conclusion, this study provides a structural basis for the resistance to Enzalutamide, which can be used to design novel effective drugs using structure-based and rationale approaches.

Interferon signalling contributes to therapy‐resistant prostate cancer progression

Interferon signalling contributes to therapy‐resistant prostate cancer progression

Ligand-free mitochondria-localized mutant AR-induced cytotoxicity in spinal bulbar muscular atrophy.

Spinal bulbar muscular atrophy (SBMA), the first identified CAG-repeat expansion disorder, is an X-linked neuromuscular disorder involving CAG-repeat-expansion mutations in the androgen receptor (AR) gene. We utilized CRISPR-Cas9 gene editing to engineer novel isogenic human induced pluripotent stem cell (hiPSC) models, consisting of isogenic AR knockout, control and disease lines expressing mutant AR with distinct repeat lengths, as well as control and disease lines expressing FLAG-tagged wild-type and mutant AR, respectively. Adapting a small-molecule cocktail-directed approach, we differentiate the isogenic hiPSC models into motor neuron-like cells with a highly enriched population to uncover cell-type-specific mechanisms underlying SBMA and to distinguish gain- from loss-of-function properties of mutant AR in disease motor neurons. We demonstrate that ligand-free mutant AR causes drastic mitochondrial dysfunction in neurites of differentiated disease motor neurons due to gain-of-function mechanisms and such cytotoxicity can be amplified upon ligand (androgens) treatment. We further show that aberrant interaction between ligand-free, mitochondria-localized mutant AR and F-ATP synthase is associated with compromised mitochondrial respiration and multiple other mitochondrial impairments. These findings counter the established notion that androgens are requisite for mutant AR-induced cytotoxicity in SBMA, reveal a compelling mechanistic link between ligand-free mutant AR, F-ATP synthase and mitochondrial dysfunction, and provide innovative insights into motor neuron-specific therapeutic interventions for SBMA.

Association study of novel single nucleotide polymorphisms of androgen receptor and estrogen receptor-α genes with male infertility in Northwest of Iran: A case-control study.

Background: Observational evidence on the association of novel single nucleotide polymorphisms (SNPs) of androgen receptor (AR) and estrogen receptor-α (ER-) genes with odds of male infertility are rare. This is particularly relevant in the Iranian population where male infertility is relatively high. Objective: This study was designed to investigate the relationship between different SNPs of these genes and male infertility among the Iranian population. Materials and Methods: The present project was a population-based, case-control study conducted on 120 idiopathic azoospermia or severe oligospermia infertile cases alongside 120 age-matched subjects enrolled as controls. Overall, 3 variants from the AR gene and 2 variants from ER- were genotyped - ARrs137852568, ARrs137852599 and AR rs137852563, and ER- rs796065354 and ER-rs104893956- using amplification refractory mutation system methods. Results: The obtained results indicated a significant association between AR rs1378525568 TT genotype as well as AR rs137852599 C allele with odds of male infertility (OR: 0.433, CI: 0.197-0.951 and OR: 0.545, CI: 0.304-0.978, respectively). Other variants of AR were not related to male infertility. A significant association was noted between predisposition polymorphism ER- rs796065354 genotypes with male infertility. This significant association was not seen between ER- rs104893956 and the risk of idiopathic azoospermia or severe oligospermia. Heterozygote overdominance was also observed in ESR rs796065354 but not in the other variants studied. Conclusion: Pieces of evidence were found on the association of novel polymorphisms of AR and ER- with male infertility among the Iranian population. However, larger studies are warranted to confirm our findings.Key words: Male infertility, Androgen receptor, Estrogen receptor-.

Mid1 is associated with androgen-dependent axonal vulnerability of motor neurons in spinal and bulbar muscular atrophy

Spinal and bulbar muscular atrophy (SBMA) is an adult-onset hereditary neurodegenerative disease caused by the expansions of CAG repeats in the androgen receptor (AR) gene. Androgen-dependent nuclear accumulation of pathogenic AR protein causes degeneration of lower motor neurons, leading to progressive muscle weakness and atrophy. While the successful induction of SBMA-like pathology has been achieved in mouse models, mechanisms underlying motor neuron vulnerability remain unclear. In the present study, we performed a transcriptome-based screening for genes expressed exclusively in motor neurons and dysregulated in the spinal cord of SBMA mice. We found upregulation of Mid1 encoding a microtubule-associated RNA binding protein which facilitates the translation of CAG-expanded mRNAs. Based on the finding that lower motor neurons begin expressing Mid1 during embryonic stages, we developed an organotypic slice culture system of the spinal cord obtained from SBMA mouse fetuses to study the pathogenic role of Mid1 in SBMA motor neurons. Impairment of axonal regeneration arose in the spinal cord culture in SBMA mice in an androgen-dependent manner, but not in mice with non-CAG-expanded AR, and was either exacerbated or ameliorated by Mid1 overexpression or knockdown, respectively. Hence, an early Mid1 expression confers vulnerability to motor neurons, at least by inducing axonogenesis defects, in SBMA.

Pathogenesis of Androgenetic Alopecia

The pathogenesis of androgenetic alopecia (AGA) is a complex interplay of genetic, hormonal, and environmental factors. In scalp follicles of susceptible individuals, androgens promote miniaturization of hair and shorten hair growth in the anagen stage, ultimately leading to AGA. The major circulating androgen, testosterone, is converted to the more potent androgen dihydrotestosterone by the enzyme 5α-reductase (5αR). Androgen receptors (ARs) and 5αR are significantly more in balding scalp hair follicles than those from nonbalding follicles. Genetic predisposition plays a crucial role in AGA. Various genetic loci including AR gene and the ectodysplasin A2 receptor (EDA2R) (AR/EDA2R locus in Xq11-q12) have been strongly implicated. The basic pathology of AGA is progressive miniaturization of the terminal hair follicles and eventual conversion of terminal hair to vellus hair. The duration of the anagen phase diminishes progressively with each cycle, while the length of telogen phase remains constant or may be prolonged. This eventually results in a reduction of the anagen to telogen ratio. With each successive shortening of hair cycle, the length of each hair shaft is reduced, and it becomes too short for the growing hair to attain even the minimum length required to reach the skin surface, resulting in an empty follicular pore. Hair follicle miniaturization leads to conversion of terminal hairs into secondary vellus hairs. Although many mechanisms have been proposed, the actual mechanism of hair miniaturization has not yet been fully elucidated. This article attempts to collate the existing information regarding the pathogenesis of AGA.

Investigation of the relationship between Androgen Receptor Gene CAG Repeat Polymorphisms and Turkish gifted students’ science attitudes

This study aims to examine the AR gene CAG polymorphisms of gifted students, and to determine whether there is a relationship between this gene region and students' attitudes towards science. The research was conducted with randomly selected gifted students (N = 100) and normally developing students (N = 100) studying at the 5th grade level in Kocaeli, Turkey during the 2017-2018 and 2018-2019 school years. In order to determine students' attitudes towards science, science and technology lesson attitude scale was applied. According to the results of the study, while there was no significant difference in terms of "enjoyment" and "social content of science" from the science and technology lesson attitude scale factors, it was found that there was a statistically significant difference in favor of gifted students from the "scale total scores" and "desire to learn" factors (p<0,05). In the genetic dimension of the study, no statistically significant difference was found between the two groups in AR gene CAG polymorphisms. In the whole sample, there was no significant relationship between the AR gene CAG polymorphisms and the "scale total score" values.

COVID-19 Severity and Androgen Receptor Polymorphism.

Simple SummarySince the early stages of the COVID-19 pandemic, it was recognized that male patients risked a more severe form of the disease. This suggested that, among other factors, a genetic predisposition could justify this issue. Thus, we investigated the CAG repeat polymorphism of the Androgen Receptor gene in a group of 142 recovered patients. Reduced androgenic signaling predisposes men to a more severe form: low testosterone levels and reduced androgen receptor activity (CAG > 23) expose the host to an excessive inflammatory response, leading downstream to the multi-organ damage seen in severe COVID-19.During the COVID-19 pandemic, the most severe form of the disease was most often seen in male patients. The aim of this study was to identify any male predispositions that could be used to predict the outcome of the disease and enable early intervention. We investigated CAG polymorphism in the androgen receptor gene and serum levels of testosterone and LH, which were considered as probably responsible for this predisposition. The study involved 142 patients who had recovered from COVID-19 at least three months previously and were classified according to their disease severity using the World Health Organization (WHO) classification. We observed a significant increase in the number of CAG repeats with increasing disease severity: the percentage of patients with more than 23 repeats increased two-fold from Grade I to Grade IV. Furthermore, testosterone levels were significantly lower in patients with severe disease. Reduced androgenic signaling could predispose men to a more severe form: low testosterone levels and a reduced androgen receptor activity (CAG > 23) expose the host to an excessive inflammatory response, leading downstream to the multi-organ damage seen in severe COVID-19.

Detection of c.G2194A mutation in \(\textit{AR}\) gene of a vietnamese patient with androgen insensitivity syndrome: a case report

Androgen insensitivity syndrome (AIS) is a rare X-linked recessive androgen receptor (AR) disorder. However, the overlap in clinical manifestations between AIS and other disorders of sex development can cause clinical diagnostic difficulties. Applying the whole coding region sequencing method is an optimal method for the diagnosis of AIS. In this study, whole-exome sequencing was performed to screen mutations in the AR gene as well as genes related to disorders of sex development (DSD). Sanger sequencing was applied to validate the mutations in the patient. One missense mutation in the AR gene which was reported previously was identified in the patient. In this site, nucleotide G is changed to A at position 2194 on cDNA (c.G2194A), leading to a substitution of aspartic at position 732 aspartic to asparagine (p.Asp732Asn). However, this is the first published case in a Vietnamese with this mutation. Our study expands the mutation spectrum of the AR gene in Vietnamese patients and confirms the usefulness of whole-exome sequencing in the diagnosis of AIS. The results of the study are the basis for supporting doctors in prenatal diagnosis and giving reasonable advice to patients and families.

The sex‐dependent role of the androgen receptor in glioblastoma: results of molecular analyses

We sought to analyse the androgen receptor (AR) in glioblastoma (GBM) due to the location of the AR gene on chromosome X, often reported with shorter survival and higher prevalence of GBM among males. Copy number (CN) and mRNA expression of AR were tested with droplet digital PCR in 91 fresh‐frozen GBM samples and 170 formalin‐fixed, paraffin‐embedded samples collected at Linköping University Hospital. The fresh‐frozen cohort was also subjected to pyrosequencing methylation analysis of 17 CpG sites in the AR promoter. Additionally, the gene expression of AR was analysed in the fresh‐frozen cohort and The Cancer Genome Atlas (TCGA) cohort of isocitrate dehydrogenase wild‐type primary GBM (135 females and 219 males). The association of AR expression and overall survival (OS) was tested with Kaplan–Meier log rank analysis after dichotomisation by maximally selected rank statistics. We found that AR CN alterations were more common in female GBM. AR gene expression correlated with methylation levels of different CpG sites in males and females but there was no difference in expression between sexes. Survival analysis of TCGA cohort revealed the opposite effect of AR overexpression on OS of males and females, with high AR expression correlating with shorter OS in females and longer OS in males. Additional gene set enrichment analysis showed that AR expression correlated with DNA repair response, especially in the male group. In summary, we found that high AR gene expression in GBM exhibits sex‐dependent effects on patient survival, which, for males, is linked to DNA repair response.

Abstract 2692: Identification of functional single nucleotide polymorphisms in cryptic exon 3 of the androgen receptor gene

Abstract Castration resistant prostate cancer (CRPC) involves the upregulation of androgen receptor variants (AR-Vs), of which AR-V7 is clinically the most relevant. By lacking the ligand-binding domain, AR-V7 is constitutively active and may therefore bypass AR signaling inhibitors. Treating CRPC involves improved AR signaling inhibitors or taxane-based chemotherapy. However, the optimal treating sequence may differ from patient to patient. The presence of AR-V7 in the nucleus of circulating PCa cells, which is associated with AR targeted therapy resistance, is used as a therapy-guiding biomarker. This stratification has a high predictive power and specificity, but its sensitivity is unsatisfying and can only be done by highly specialized laboratories. A PCR/sequencing based test would improve the sensitivity of this biomarker, but it requires a better understanding of AR-V7’s functional regulation. Therefore, we aim here to analyze single nucleotide polymorphisms (SNPs) in the 3’ untranslated region (UTR) of AR-V7 that might have an impact on AR-V7’s expression and/or functional activity. The LD trait tool of NIH was used to search for trait association with AR cryptic exon (CE3) SNPs. Four RNA binding motif databases (oRNAment, ATtRACT, RBP map, and RBPDB) and SpliceAid v2 were used for evaluating SNPs in their capacity to alter motifs. By CRISPR/CAS9 mediated non-homologous end joining (NHEJ) these predictions were assessed experimentally using qPCR and Westen Blot. SNP rs5918762 was selected as it is in linkage disequilibrium with several PCa tagSNPs (rs5919393, rs5919432). rs5918762T/C is characterized by an unequal minor allele frequency (MAF) distribution among different populations. Using an in silico approach, this SNP is predicted to destroy/create a binding site for the splicing machinery involved protein SRSF9. Disrupting this SNP region via NHEJ resulted respectively in an increased and decreased expression of AR-FL and AR-V7 mRNA in 22RV1 cells (C allele). Additionally, analysis of the SU2C dataset (CRPC patients) correlated SRSF9 expression with AR-V7 expression. Subsequently, SRSF9 knock out (KO) resulted in reduced AR-V7 mRNA expression. Our data suggests that SNP rs5918762T/C is located in a region important for CE3 inclusion during AR splicing, which might involve SRSF9. Further validation of these results is in need and encompasses splicing assays by an AR-V7 mini-gene assay, protein-RNA interaction assays and an analysis of a lack of effect in cell lines expressing the T allele. Citation Format: Jasper Van Goubergen, Florian Handle, Marcus V. Cronauer, Frédéric R. Santer. Identification of functional single nucleotide polymorphisms in cryptic exon 3 of the androgen receptor gene [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2692.

Abstract 653: Molecular pathology of metastatic prostatic adenocarcinoma treated with bipolar androgen therapy (BAT) reveals a correlation between MYC mRNA and protein

Abstract Molecular analysis of tissue samples from metastatic cancer lesions can improve our understanding of drug response and resistance. Since prostate cancer cells initially require androgen signaling through the androgen receptor (AR) for proliferation, the treatment of metastatic prostate cancer involves surgical or chemical castration. While most patients respond initially, nearly all develop acquired resistance to combined androgen blockade using both first and second line agents. This resistance is often related to overexpression of AR, which is frequently driven by AR gene amplification. In some patients, this increased AR appears to render tumor cells sensitive to high dose androgens in a manner that paradoxically inhibits their growth. Bipolar Androgen Therapy (BAT) was introduced several years ago at our institution in which patients with castration resistant prostate cancer (CRPC) are treated intermittently with high dose testosterone. Prior clinical trials have shown that BAT can produce biochemical and objective responses, and may re-sensitize prostate cancer to subsequent second generation AR inhibitors. To define the mechanism(s) by which BAT results in tumor regression, we performed a clinical trial (NCT03554317) for patients with CRPC that included biopsies of soft tissue metastases before BAT and after 3 cycles of BAT (C4D1). Up to four tissue cores were taken per biopsy with two cores for formalin fixation and paraffin embedding (FFPE) and the others snap frozen. Histologically viable tumor cells were present for both the pretreatment and C4D1 time points for 24 of the 42 enrolled patients. The FFPE samples were stained for H&E and by IHC for AR, MYC and Ki67. MYC and Ki67 IHC stained slides were subjected to quantitative image analysis using HALO software (Indica Labs). Adequate frozen tumor tissue was available for laser capture microdissection and adequate amounts of RNA were obtained from 15 patients with paired pretreatment and C4D1 biopsies. RNAseq libraries were prepared using the NuGEN Ovation RNA-Seq System V2 and barcoded libraries were sequenced to an average depth of > 100 million reads per sample on an Illumina NovaSeq. Gene expression values were obtained with RSEM using Star aligner with GRCh38 (human). When comparing the C4D1 samples to the pretreatment samples, there were marked decreases in tumor MYC protein levels in approximately half of the treated patients, which was associated with decreased Ki67, decreased tumor volume, and prolonged progression-free survival on BAT. Using an image analysis computed H-SCORE for MYC, there was a strong correlation between MYC protein levels and MYC mRNA using RNAseq (r=0.81, p = 2.3 x 10-7). This indicates that MYC protein levels correlate with MYC mRNA and that reductions of MYC protein by BAT are likely related to reductions of MYC mRNA in clinical metastatic tissue samples. Citation Format: Carolina Gomes Alexandre, Tracy Jones, Jessica L. Hicks, John T. Isaacs, Anuj Gupta, Alyza Skaist, Laura Sena, Jennifer Meyers, Emmanuel Antonarakis, Mark Markowski, Samuel Denmeade, Srinivasan Yegnasubramanian, Angelo Michael De Marzo. Molecular pathology of metastatic prostatic adenocarcinoma treated with bipolar androgen therapy (BAT) reveals a correlation between MYC mRNA and protein [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 653.

Abstract 3625: Clonal architecture and evolution of treatment-resistant prostate cancer via deep whole-genome ctDNA sequencing

Abstract Background: Circulating tumor DNA (ctDNA) in blood plasma is an emerging tool for clinical cancer genotyping and longitudinal disease monitoring. However, integration of ctDNA tests into clinical management is critically impeded by the poor understanding of the distinct somatic populations comprising bulk ctDNA—including their relationship to synchronous metastatic tissue, and their temporal dynamics during standard-of-care treatment. Prior approaches relying on targeted and/or low-resolution techniques (e.g. targeted exon sequencing, low-pass (shallow) whole-genome sequencing; WGS) do not permit comprehensive dissection of clonal architecture and unbiased analysis of putative resistance mechanisms. Methods: We performed deep WGS on serial plasma ctDNA (median depth: 185×) and synchronous metastatic tissue biopsies with high tumor purity from 35 patients with metastatic castration-resistant prostate cancer. We developed a subclonal reconstruction algorithm optimized for our data enabling resolution of per-patient evolutionary histories and ctDNA clonal composition. ctDNA nucleosome footprinting was used to infer mRNA abundance in synchronously biopsied metastases and androgen receptor (AR) transcription factor activity at 3224 AR binding sites (ARBS). Results: We comprehensively assess all classes of genomic alterations and demonstrate that ctDNA harbors greater populational heterogeneity than metastatic tissue (p<0.001). The evolutionary histories of ctDNA populations indicate frequent whole-genome doubling and attenuation of C>T aging-associated mutation signature during subclonal differentiation. Although driver alterations were largely concordant between tissue and ctDNA, each individual metastasis contributed only a minor share of total ctDNA (average ctDNA contribution: 17%). By comparing serial ctDNA before and after clinical progression on potent AR pathway inhibitors, we reveal population restructuring converging solely on AR copy augmentation as the dominant genomic driver of acquired treatment-resistance. Nucleosome depletion at transcription start-sites is highly correlated with same-patient metastatic tissue mRNA abundance, indicating that ctDNA fragmentomics can recapitulate transcriptomic patterns in metastatic lesions. Most ctDNA samples exhibited strong ARBS nucleosome depletion which correlated with AR gene copy number (R=0.36, p=0.003). Finally, serial ctDNA nucleosome profiling at ARBS revealed adaptive transcriptomic resistance to AR pathway inhibitors, including lineage switch to a neuroendocrine-like (AR-low) state. Conclusions: We show that the populations comprising ctDNA are typically complex and more heterogeneous than those found in bulk WGS of a synchronous metastasis. Our work advocates for liquid biopsy as a comprehensive multi-omic discovery tool for cancers with high ctDNA fractions. Citation Format: Cameron Herberts, Matti Annala, Joonatan Sipola, Sarah W. Ng, Xinyi E. Chen, Anssi Nurminen, Olga Korhonen, Aslı D. Munzur, Kevin Beja, Elena Schönlau, Cecily Q. Bernales, Elie Ritch, Jack V. Bacon, Nathan A. Lack, Matti Nykter, Rahul Aggarwal, Eric J. Small, Martin E. Gleave, David A. Quigley, Felix Y. Feng, Kim N. Chi, Alexander W. Wyatt. Clonal architecture and evolution of treatment-resistant prostate cancer via deep whole-genome ctDNA sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3625.

Androgen receptor gene deficiency results in the reduction of steroidogenic potential in porcine luteal cells

Luteal steroidogenesis is critical to implantation and pregnancy maintenance in mammals. The role of androgen receptors (AR) in the progesterone (P4) producing luteal cells of porcine corpus luteum (CL) remains unexplored. The aim of the present study was to establish AR gene knock out (KO) porcine luteal cell culture system model by CRISPR/Cas9 genome editing technology and to study the downstream effects of AR gene deficiency on steroidogenic potential and viability of luteal cells. For this purpose, genomic cleavage detection assay, microscopy, RT-qPCR, ELISA, annexin, MTT, and viability assay complemented by bioinformatics analysis were employed. There was significant downregulation (p < 0.05) in the relative mRNA expression of steroidogenic marker genes STAR, CYP11A1, HSD3B1 in AR KO luteal cells as compared to the control group, which was further validated by the significant (p < 0.05) decrease in the P4 production. Significant decrease (p < 0.05) in relative viability on third passage were also observed. The relative mRNA expression of hypoxia related gene HIF1A was significantly (p < 0.05) downregulated in AR KO luteal cells. Protein-protein interaction analysis mapped AR to signaling pathways associated with luteal cell functionality. These findings suggests that AR gene functionality is critical to luteal cell steroidogenesis in porcine.

Exploring the Role of Posttranslational Modifications in Spinal and Bulbar Muscular Atrophy.

Spinal and Bulbar Muscular Atrophy (SBMA) is an X-linked adult-onset progressive neuromuscular disease that affects the spinal and bulbar motor neurons and skeletal muscles. SBMA is caused by expansion of polymorphic CAG trinucleotide repeats in the Androgen Receptor (AR) gene, resulting in expanded glutamine tract in the AR protein. Polyglutamine (polyQ) expansion renders the mutant AR protein toxic, resulting in the formation of mutant protein aggregates and cell death. This classifies SBMA as one of the nine known polyQ diseases. Like other polyQ disorders, the expansion of the polyQ tract in the AR protein is the main genetic cause of the disease; however, multiple other mechanisms besides the polyQ tract expansion also contribute to the SBMA disease pathophysiology. Posttranslational modifications (PTMs), including phosphorylation, acetylation, methylation, ubiquitination, and SUMOylation are a category of mechanisms by which the functionality of AR has been found to be significantly modulated and can alter the neurotoxicity of SBMA. This review summarizes the different PTMs and their effects in regulating the AR function and discusses their pathogenic or protective roles in context of SBMA. This review also includes the therapeutic approaches that target the PTMs of AR in an effort to reduce the mutant AR-mediated toxicity in SBMA.

The number of androgen receptor CAG repeats and mortality in men

Introduction The androgen receptor (AR) mediates peripheral effects of testosterone. Evidence suggests that the number of CAG repeats in exon-1 of the AR gene negatively correlates with AR transcriptional activity. The aim of this analysis was to determine the association between CAG repeat number and mortality in men. Methods Men aged 40–79 years were recruited from primary care for participation in the UK arm of the European Male Aging Study between 2003 and 2005. Cox proportional hazards modelling was used to determine the association between CAG repeat number/mortality. Results were expressed as hazard ratios(HR)/95% confidence intervals (CI). Results 312 men were followed up. The mean baseline age was 59.5 years. At follow up, 85/312(27%) men had died. CAG repeat length ranged from 14 to 39, with the highest proportion of CAG repeat number at 21 repeats(16.4%). In a multivariable model, using men with CAG repeat numbers of 22-23 as the reference, men with a lower number of CAG repeats(<22) showed a trend for a higher mortality in the follow-up period (HR 1.46 (0.75, 2.81)) as did men with higher number of repeats (>23) (1.37 (0.65, 2.91)). Conclusion Our data suggest that CAG repeat number may partially influence the risk of mortality in men. Further larger studies are required to quantify the effect.

PTCH1 and AXIN2 modulation of AR copy number effects on AR gene overexpression in metastatic castration resistant prostate cancer (mCRPC).

e17026 Background: Androgen receptor (AR) signaling is a critical pathway in prostate cancer progression. Reactivation of the AR pathway is a key driver in mCRPC. Patients with mCRPC often develop resistance to novel AR signaling inhibitors (ARSIs) such as enzalutamide. AR inhibitor resistance leads to shorter overall and progression-free survival and can be attributed to AR gene amplification with subsequent AR overexpression and androgen-sensitization in prostate tumors. Identifying novel modulators of AR amplification in patients progressing on ARSIs may lead towards potential targets in drug discovery. Methods: In this cross-sectional study, an in silico patient model was developed on prescribed drug therapies and failed therapies patient information, PSA measures, ̃100 mutation variables including somatic, germline, and gain/loss mutations, and ̃1K gene expressions data from 275 mCRPC patients obtained from the Tempus database using GNS Healthcare’s Causal artificial intelligence technology, REFS. A causal network model was reconstructed based on patient data with inferred effect estimates. The network model was topologically surveyed for biological interactions. Results: Causal analysis of this model uncovered two germline mutations, located in PTCH1 and AXIN2, which modify the effect of AR copy number gain ( ARgain+ : copy number 6, ARgain- : copy number &lt; 6) on AR gene expression. For PTCH1-mutant group, there was a 2-fold increase in AR gene expression in ARgain+ patients compared to ARgain- patients (p = 2.1e-12), while only 1.4 fold increase in AR gene expression from the PTCH1 non-mutant group (p = 6.3e-08). Similarly, there was a 2-fold increase in AR gene expression in ARgain+ patients compared to ARgain- patients (p = 7.2e-16) for the AXIN2-mutant group, while only one-fold increase in AR gene expression with the AXIN2 non-mutant group (p = 0.001). The C to T missense mutation in codon 3746 in PTCH1 and codon 148 in AXIN2 have higher prevalences, 55% and 72%, respectively in this mCRPC cohort compared to their population allele frequencies, 38% and 47%, respectively. Conclusions: PTCH1 and AXIN2 mutations from our analyses is consistent with a literature reported role for Hedgehog signaling and Wnt/-catenin signaling pathways, respectively, influencing the disease progression in castration-resistant prostate cancer. Our findings suggest that the missense germline mutations in PTCH1 and AXIN2 predicts response to enzalutamide and other ARSIs in CRPC setting, and propose potential targets for combination therapy to overcome ARSI drug resistance in hormone-refractory prostate cancer. [Table: see text]

Mutations in AR or SRD5A2 Genes: Clinical Findings, Endocrine Pitfalls, and Genetic Features of Children with 46,XY DSD

Objective:Androgen insensivity syndrome (AIS) and 5α-reductase deficiency (5α-RD) present with indistinguishable phenotypes among the 46,XY disorders of sexual development (DSD) that usually necessitate molecular analyses for the definitive diagnosis in the prepubertal period. The aim was to evaluate the clinical, hormonal and genetic findings of 46,XY DSD patients who were diagnosed as AIS or 5α-RD.Methods:Patients diagnosed as AIS or 5α-RD according to clinical and hormonal evaluations were investigated. Sequence variants of steroid 5-α-reductase type 2 were analyzed in cases with testosterone/dihydrotestosterone (T/DHT) ratio of ≥20, whereas the androgen receptor (AR) gene was screened when the ratio was <20. Stepwise analysis of other associated genes were screened in cases with no causative variant found in initial analysis. For statistical comparisons, the group was divided into three main groups and subgroups according to their genetic diagnosis and T/DHT ratios.Results:A total of 128 DSD patients from 125 non-related families were enrolled. Birth weight SDS and gestational weeks were significantly higher in 5α-RD group than in AIS and undiagnosed groups. Completely female phenotype was higher in all subgroups of both AIS and 5α-RD patients than in the undiagnosed subgroups. In those patients with stimulated T/DHT <20 in the prepubertal period, stimulated T/DHT ratio was significantly lower in AIS than in the undiagnosed group, and higher in 5α-RD. Phenotype associated variants were detected in 24% (n=18 AIS, n=14 5α-RD) of the patients, revealing four novel AR variants (c.94G>T, p.Glu32*, c.330G>C, p.Leu110=; c.2084C>T, p.Pro695Leu, c.2585_2592delAGCTCCTG, p.(Lys862Argfs*16), of these c.330G>C with silent status remained undefined in terms of its causative effects.Conclusion:T/DHT ratio is an important hormonal criterion, but in some cases, T/DHT ratio may lead to diagnostic confusion. Molecular diagnosis is important for the robust diagnosis of 46,XY DSD patients. Four novel AR variants were identified in our study.

089 Complete androgen insensitivity syndrome (CAIS): Gonadectomy, hormonal replacement therapy and bone mineral density

Objective: To evaluate the effect of pre- or post-pubertal gonadectomy, coupled with subsequent hormonal replacement therapy, on bone mineral density in CAIS patients. Study Design: Retrospective cross-sectional study with in a tertiary referral pediatric and adolescent gynecology unit. The population consisted of Sixteen CAIS patients with diagnosis made on the basis of clinical phenotype, 46XY karyotype and mutational analysis of androgen receptor gene. Data were collected from medical records.

Genomic aberrations associated with overall survival (OS) in metastatic castration-sensitive prostate cancer (mCSPC) treated with apalutamide (APA) or placebo (PBO) plus androgen deprivation therapy (ADT) in TITAN.

5066 Background: TITAN, a phase 3 PBO-controlled study in patients (pts) with mCSPC, showed APA + ADT improved radiographic progression-free survival and OS vs PBO + ADT. In this exploratory analysis, we report the relationships between biomarkers and OS in TITAN. Methods: Circulating tumor (ct)DNA and genomic aberrations in 17 PC-related genes, including androgen receptor (AR), were assessed at baseline (BL; 114 pts) and end of study treatment (EOST; 129 pts) using next-generation sequencing. ctDNA was assessed qualitatively; genomic aberrations were assessed within ctDNA-positive samples as inactivation (heterozygous/homozygous deletion or single nucleotide variant [SNV]) or activation (amplification or SNV). Associations of detected ctDNA/aberrations at BL or EOST with OS, and biomarkers at EOST with OS on subsequent therapies, were evaluated using univariate or multivariate analyses and Cox proportional hazards model; results were stratified by treatment arm. Results: Among pts from both treatment groups, 36% had detectable ctDNA, of which 27% had any genomic AR aberration and 24% had AR gene amplification at BL; prevalence of these biomarkers increased significantly from BL to EOST (Table). The most prevalent non-AR aberrations at BL ( TP53, homologous recombination repair [HRR] pathway, PTEN, RB1, and PIK3CA genes) increased at EOST but not significantly (Table). Among assessed aberrations, presence of ctDNA or any AR genomic aberrations at BL (HR, 1.9 or 6.7; all p &lt; 0.05) and any AR genomic aberrations or PI3K pathway activation at EOST (1.7, p &lt; 0.05 or 2.2, p &lt; 0.001) was significantly associated with poor OS in multivariate analyses from both treatment groups. In univariate analyses of pts who received subsequent therapy (chemotherapy: 106; hormonal therapy: 161), worse OS was associated only with PIK3CA activation, PI3K pathway activation, or TP53 inactivation at EOST (3.7, p &lt; 0.05; 2.4, p &lt; 0.05; 3.0, p &lt; 0.01, respectively) in chemo-treated pts. A small sample size in some biomarker subgroups limits interpretation. Conclusions: These hypothesis-generating data from TITAN show that presence of ctDNA or select AR and non-AR biomarkers at BL or EOST were associated with poor OS. The predictive value of these biomarkers for survival in mCSPC needs further confirmation. Clinical trial information: NCT02489318. [Table: see text]