Reduced mesencephalic astrocyte-derived neurotrophic factor expression by mutant androgen receptor contributes to neurodegeneration in a model of spinal and bulbar muscular atrophy pathology

Spinal and bulbar muscular atrophy is a neurodegenerative disease caused by extended CAG trinucleotide repeats in the androgen receptor gene,which encodes a ligand-dependent transcription facto r.The mutant androgen receptor protein,characterized by polyglutamine expansion,is prone to misfolding and forms aggregates in both the nucleus and cytoplasm in the brain in spinal and bulbar muscular atrophy patients.These aggregates alter protein-protein interactions and compromise transcriptional activity.In this study,we reported that in both cultured N2a cells and mouse brain,mutant androgen receptor with polyglutamine expansion causes reduced expression of mesencephalic astrocyte-de rived neurotrophic factor.Overexpressio n of mesencephalic astrocyte-derived neurotrophic factor amelio rated the neurotoxicity of mutant androgen receptor through the inhibition of mutant androgen receptor aggregation.Conversely.knocking down endogenous mesencephalic astrocyte-derived neurotrophic factor in the mouse brain exacerbated neuronal damage and mutant androgen receptor aggregation.Our findings suggest that inhibition of mesencephalic astrocyte-derived neurotrophic factor expression by mutant androgen receptor is a potential mechanism underlying neurodegeneration in spinal and bulbar muscular atrophy.

Androgen receptors are expressed in a variety of human fetal extragenital tissues： an immunohistochemical study

Aim： To investigate the expression of androgen receptors in the extragenital tissues of developing human embryo. Methods： Using immunohistochemistry, we investigated the distribution of androgen receptor （AR） in the extragenital tissues of paraffin-embedded tissue sections of first trimester （8-12 weeks gestation） human embryos. Gender was determined by polymerized chain reaction. Results： There were no differences in the expression and distribution of AR in male and female embryos at any stage of gestation. AR expression was seen in the thymus gland. The bronchial epithelium of the lungs showed intense positive staining with surrounding stroma negative. Furthermore, positive staining for androgen receptor was exhibited in the spinal cord with a few positive cells in the surrounding tissues. Cardiac valves also showed strong positive staining but with faint reactivity of the surrounding cardiac muscle. There was no staining in kidney, adrenal, liver or bowel. Conclusion： This study demonstrates that immunoreactive AR protein is present in a wide variety of human first trimester fetal tissues and shows the potential for androgen affecting tissues, which are mostly not considered to be androgen dependent. Moreover, it implies that androgen might act as atrophic factor and affect the early development of these organs rather than simply sexual differentiation.

Correlations between Expression of Estrogen and Androgen Receptors and the Clinical Characteristics of Prolactinoma~*

Objective： To study the correlations between estrogen receptor （ER） and androgen receptor （AR） and the clinical presentations of prolactinoma and investigate the effect of ER and AR expression on the pathogenesis of prolactinoma in sexual difference. Methods： The clinical data of 30 patients who had undergone transsphenoidal operations in Tongji Hospital from December 2000 to December 2001 were reviewed retrospectively. The clinical information included sex, age, serum-prolactin, size, tumor invasiveness, history of use of bromocriptine and frequency of recurrence. In 20 out of the 30 patients, the ER and AR expression was detected by using immunohistochemistry method. With help of Chi-square test, the relationship between ER, AR and the clinical presentations was analyzed. Results： The statistical values revealed that there was no significant correlation between the ER and AR expression levels with the clinical presentations such as sex, age, tumor size or tumor invasiveness among the 20 patients studied （P〉0.05）. Conclusion： The expression of ER or AR is not influenced by the clinical data of prolactinoma such as sex, age, tumor diameter or extent of tumor invasiveness. The tumor is more aggressive in males than in females. In maroadenoma or tumor with hyperprolactineamia （〉200 ng/mL） simple surgical treatment can＇t successfully cure the prolactinoma. Post-operative bromocriptine therapy can＇t be determined by the sex of the patients, but is greatly related to the tumor size and serum-prolactin level before operation.

Mating behavior induces changes of expression of Fos protein,plasma testosterone and androgen receptors in the accessory olfactory bulb (AOB) of the male mandarin vole Microtus mandarinus

In order to investigate the neuroendocrine mechanism of the mating behavior in the adult male mandarin voles Microtus mandarinus,the radioimmunoassay(RIA)and immunohistochemistry methods were used to investigate the differences in plasma testosterone(T)concentrations and distribution of T immunoreactive neurons(T-IRs),androgen receptor immunoreactive neurons(AR-IRs)and Fos protein immunoreactive neurons(Fos-IRs)in the accessory olfactory bulb(AOB)and the main olfactory bulb(MOB)following exposure to clean hard-wood shavings(control group),soiled bedding(exposure group)or contact with an estrous female(mating group).Results showed that plasma T concentration was significantly higher in the mating group than that in the exposure group,and both the mating group and the exposure group displayed significantly higher plasma T concentration than the control group.T-IRs,AR-IRs and Fos-IRs were investigated with the immunohistochemistry method in granule cell(GC)and mitral cell(MC)of the MOB and the AOB in the three groups.There were significantly more T-IRs,AR-IRs and Fos-IRs in MC and GC of the AOB in the mating group than that in the exposure group or the control group.T-IRs,AR-IRs and Fos-IRs did not show significant differences between the exposure group and the control group.Furthermore,obvious differences in MC and GC of the MOB were not found among the three groups.The results confirm that both changes of T and AR in the AOB might be underlying mating behavior in the adult male mandarin voles.

miR-141-3p Suppresses Expression of Androgen Receptors and Functions as a Tumor Suppressor Gene in Prostate Carcinogenesis

Background: Prostate cancer (PCa) is a leading cause of tumor mortality in Western societies. In China, the PCa mortality rate is increasing yearly. Androgen receptors (ARs) and microRNAs (miRNAs) play central roles in prostate carcinogenesis and progression. Methods: To characterize the underlying molecular mechanisms, we compared the miRNA profiles of early PCa (G ≤ 7), advanced PCa (G > 7) and non-tumor prostate tissues using deep-sequencing. The target genes of differentially expressed miRNAs were predicted by bioinformatics analysis and confirmed by luciferase reporter assays and Western blot (WB) and quantitative reverse transcription-PCR (qRT-PCR) analyses. Finally, we performed in vitro functional studies by inducing or inhibiting miR-141-3p expression using an artificial mimic or inhibitor. Results: A computational search implicated the open reading frame (ORF) of AR mRNA as a potential miR-141-3p target site. The qRT-PCR, WB and luciferase reporter assays revealed a reverse regulatory effect of miR-141-3p on AR. Mutation of the potential miR-141-3p binding site in the AR ORF resulted in a loss of responsiveness to the corresponding miRNA. Moreover, miR-141-3p expression levels were unchanged in early PCas, but were obviously increased in advanced PCas. MiR-141-3p overexpression inhibited RWPE-1 cell proliferation, mobility, and prohibited the entry of cells into the G2-S-M phase;miR-141-3p inhibition had the inverse effects. At the same time, we tested miR-141-3p’s functions in PC-3 and VCaP prostate cancer cell lines. Conclusions: Taken together, our results indicate that miR-141-3p targets AR and its downstream signaling pathways, and functions as a tumor suppressor miR in PCa carcinogenesis by suppressing cell growth and mobility, but the effect is not significant in maglinant PCas. MiR-141-3p is implicated as a novel therapeutic target for early PCa.

三阴性乳腺癌组织中EGR1、AR、H3K4me3表达与其临床病理特征及预后的相关性

目的探讨三阴性乳腺癌组织中早期生长反应基因1(EGR1)、雄激素受体(AR)、组蛋白H3第4位赖氨酸三甲基化(H3K4me3)表达与其临床病理特征及预后的相关性。方法回顾性分析89例三阴性乳腺癌患者的临床资料,所有患者均行手术治疗,采用免疫组化染色法测定EGR1、AR、H3K4me3表达,比较肿瘤组织及癌旁正常组织内EGR1、AR、H3K4me3表达差异,分析EGR1、AR、H3K4me3表达与其临床病理的关系,分析EGR1、AR、H3K4me3表达与其预后的关系。结果肿瘤组织内EGR1阳性表达率、AR阳性表达率低于对照组,H3K4me3阳性表达率高于对照组,差异有统计学意义(P<0.05);EGR1阳性表达、AR阳性表达患者临床分期Ⅰ~Ⅱ期、无淋巴结转移、中高分化占比高于EGR1阴性表达、AR阴性表达患者,H3K4me3阳性表达患者临床分期Ⅲ期、淋巴结转移、低分化占比高于H3K4me3阴性表达患者,差异有统计学意义(P<0.05);随访1年,89例患者共36例出现复发转移,发生率为40.45%(36/89);复发转移组EGR1阳性表达、AR阳性表达率低于未复发转移组,H3K4me3阳性表达率高于未复发转移组,差异有统计学意义(P<0.05)。结论EGR1、AR在三阴性乳腺癌中多呈阴性表达,H3K4me3则以阳性表达为主,三者表达均与临床分期、淋巴结转移及分化程度存在密切关系,或可作为临床治疗的新靶点。

Androgen receptor signaling in hepatocellular carcinoma and pancreatic cancers

Hepatocellular carcinoma (HCC) and pancreatic cancer remain difficult to treat, and despite the ongoing development of new treatments, the overall survival rate has only modestly improved over the past decade. Liver and pancreatic progenitors commonly develop from endoderm cells in the embryonic foregut. A previous study showed that HCC and pancreatic cancer cell lines variably express androgen receptor (AR), and these cancers and the surrounding tissues also express AR. AR is a ligand-dependent transcription factor that belongs to the nuclear receptor superfamily. Androgen response element is present in regulatory elements on the AR-responsive target genes, such as transforming growth factor beta-1 (TGF beta-1) and vascular endothelial growth factor (VEGF). It is well known that the activation of AR is associated with human carcinogenesis in prostate cancer as well as HCC and pancreatic cancer and that GRP78, TGF beta, and VEGF all play important roles in carcinogenesis and cancer development in these cancers. HCC is a male-dominant cancer irrespective of its etiology. Previous work has reported that vertebrae forkhead box A 1/2 are involved in estrogen receptors and/or AR signaling pathways, which may contribute to the gender differences observed with HCC. Our recent work also showed that AR has a critical role in pancreatic cancer development, despite pancreatic cancer not being a male dominant cancer. Aryl hydrocarbon (or dioxin) receptor is also involved in both HCC and pancreatic cancer through the formation of complex with AR. It is possible that AR might be involved in their carcinogenesis through major histocompatibility complex class&#x02005;I&#x02005;chain-related gene A/B. This review article describes AR and its role in HCC and pancreatic cancer and suggests that more specific AR signaling-inhibitors may be useful in the treatment of these &#x0201c;difficult to treat&#x0201d; cancers.

In situ hybridization assay of androgen receptor gene in hepatocarcinogenesis

AIM To determine the correlation between expression of androgen receptor (AR) gene and hepatocarcinogenesis. METHODS Male SD rats were used as experimental animals and the animal model of experimental hepatocarcinoma was established by means of 3′ me DAB administration. Androgen receptor mRNA was detected by a non radioactive in situ hybridization assay in neoplastic and non neoplastic liver tissues. RESULTS The expression of androgen receptor mRNA was observed only in neoplastic cells and some atypical hyperplastic cells. In the liver tissue of control animal and the remaining normal liver cells adjacent to the carcinoma tissue, no positive signal was seen. CONCLUSION Androgen has an important correlation with hepatocarcinogenesis and the expression of androgen receptor gene might be a mark event during hepatocarcinogenesis.

Chimeric molecules facilitate the degradation of androgen receptors and repress the growth of LNCaP cells

Post-translational degradation of protein plays an important role in cell life. We employed chimeric molecules （dihydrotestosterone-based proteolysis-targeting chimeric molecule [DHT-PROTAC]） to facilitate androgen receptor （AR） degradation via the ubiquitin-proteasome pathway （UPP） and to investigate the role of AR in cell proliferation and viability in androgen-sensitive prostate cancer cells. Western blot analysis and immunohistochemistry were applied to analyse AR levels in LNCaP cells after DHT-PROTAC treatment. Cell counting and the 3-（4,5-dimethylthiazol-2-yl）-2,5- diphenyl tetrazolium bromide （MTT） cell viability assay were used to evaluate cell proliferation and viability after AR elimination in both LNCaP and PC-3 cells. AR was tagged for elimination via the UPP by DHT-PROTAC, and this could be blocked by proteasome inhibitors. Degradation of AR depended on DHT-PROTAC concentration, and either DHT or an ALAPYIP-（arg）8 peptide could compete with DHT-PROTAC. Inhibition of cell proliferation and decreased viability were observed in LNCaP cells, but not in PC-3 or 786-0 cells after DHT-PROTAC treatment. These data indicate that AR elimination is facilitated via the UPP by DHT-PROTAC, and that the growth of LNCaP cells is repressed after AR degradation.

Role of sex steroid receptors in pathobiology of hepatocellular carcinoma

The striking gender disparity observed in the incidence of hepatocellutar carcinoma （HCC） suggests an important role of sex hormones in HCC pathogenesis. Though the studies began as early as in 1980s, the precise role of sex hormones and the significance of their receptors in HCC still remain poorly understood and perhaps contribute to current controversies about the potential use of hormonal therapy in HCC. A comprehensive review of the existing literature revealed several shortcomings associated with the studies on estrogen receptor （ER） and androgen receptor （AR） in normal liver and HCC. These shortcomings include the use of less sensitive receptor ligand binding assays and immunohistochemistry studies for ERα alone until 1996 when ERβ isoform was identified. The animal models of HCC utilized for studies were primarily based on chemical-induced hepatocarcinogenesis with less similarity to virus-induced HCC pathogenesis. However, recent in vitro studies in hepatoma cells provide newer insights for hormonal regulation of key cellular processes including interaction of ER and AR with viral proteins. In light of the above facts, there is an urgent need for a detailed investigation of sex hormones and their receptors in normal liver and HCC. In this review, we systematically present the information currently available on androgens, estrogens and their receptors in normal liver and HCC obtained from in vitro, in vivo experimental models and clinical studies. This information will direct future basic and clinical research to bridge the gap in knowledge to explore the therapeutic potential of hormonal therapy in HCC.

Localization and potential function of androgen receptor in rat salivary gland

Aim： To investigate the localization and quantity of androgen receptor （AR） in the salivary glands of rats with further analysis on the effect of castration. Methods： Sixty male Wistar rats, aged 30-60 days, were randomly divided into three groups （castrated, sham-operated and normal controls） with 20 rats in each group. The rats in the castrated group were castrated and the submaxillary glands were removed after 1 week. The salivary glands of the rats in the sham-operated and the normal control groups were also removed. Parts of the salivary glands were fixed for immuohistochemistry and in situ hybridization assays. Other parts were used for Western blot. Results： AR immunoreactivity in the three groups was localized in the glandular epithelial cells of the serous acinus and the glandular duct of the salivary gland, mainly in the nuclei. AR mRNA hybridization signals in the salivary glands of the castrated group were mainly distributed in the epithelial cells of the convoluted and secretary ducts; AR mRNA in the sham-operated and the normal control groups were found in the epithelial cells of the convoluted, the secretary and the excretory ducts. The quantity of AR in the salivary glands was decreased significantly in the castrated rats compared with the sham-operated and the normal controls. Moreover, epidermal growth factor （EGF） secreted by the salivary glands was also decreased in the castrated rats. Conclusion： Castration appears to affect the production of AR in the salivary gland and the distribution of the AR mRNA and could further affect the function of the salivary gland. The changes of AR and the distribution of AR mRNA may play an important role in the interactions between the testes and the salivary gland. （Asian J Androl 2005 Sep; 7： 295-301）

AR、SKP2、SOX10、PD-L1及TIL表达在三阴性乳腺癌中的意义

目的:探索雄激素受体(androgen receptor,AR)、S期激酶相关蛋白2(S-phase kinase-associated protein 2,SKP2)、性别决定区Y相关的HMG盒含因子10(sry-related HMG box-containing factor 10,SOX10)、程序性死亡配体1(programmed death-ligand 1,PD-L1)及肿瘤浸润性淋巴细胞(tumor infiltrating lymphocyte,TIL)在三阴性乳腺癌(triple negative breast cancer,TNBC)表达与临床病理特征和预后的关系。方法:根据苏木精-伊红染色(hematoxylineosin, HE)染色切片评判109例TNBC瘤巢内TIL的比例,采用Leica Bond-Max全自动免疫组化仪检测TNBC组织中AR、SKP2、SOX10、PD-L1的表达。分析以上各生物指标与临床病理特征间的关系,并采用kaplan-Meier、Log-rank进行生存分析。结果:95例患者获得随访,中位随访时间为48个月,中位无病生存时间(disease-free survival, DFS)为42个月,中位总生存时间(overall survival, OS)48个月。在TNBC中,AR阳性表达与淋巴结转移阴性(P=0.009)、肿瘤最大径<2 cm(P=0.008)相关,TIL高表达与低级别TNBC相关(P=0.007),SKP2阳性表达与神经/脉管侵犯阳性(P=0.011)、高级别TNBC相关(P=0.002),SOX10阳性表达与淋巴结转移阳性(P=0.022)、高级别TNBC(P=0.005)相关,PD-L1阳性表达与淋巴结转移阳性(P=0.020)、神经/脉管侵犯阳性(P=0.006)、高级别TNBC(P=0.042)相关。生存分析显示,SKP2、SOX10阳性表达与更差的DFS(P=0.007、P<0.001)和OS(P=0.013、P<0.001)相关,TIL高表达与更好的DFS(P=0.016)及OS(P=0.004)相关。在生物表志物的联合表达中,AR+/SKP2-、AR+/SOX10-与更好的DFS(P=0.004、P<0.001)及OS(P=0.007、P=0.001)相关,SOX10+/低TIL、PD-L1+/低TIL与更差的DFS(P<0.001、P=0.008)及OS(P=0.001、P=0.002)相关,AR-/低TIL者具有更差的OS(P=0.014)。SKP2(HR=4.143,95%CI为1.578~10.875)、SOX10(HR=7.578,95%CI为2.067~27.782)的阳性表达是影响TNBC患者DFS的独立预后因子,SKP2(HR=3.758,95%CI为1.400~10.084)、SOX10(HR=5.131,95%CI为1.316~20.000)及TIL(HR=0.375,95%CI为0.154~0.917)的阳性表达是TNBC患者OS的独立预后因子(P均<0.05)。结论:在TNBC中,AR阳性、TIL高表达与具有更好预后的临床病理特征相关,SKP2、SOX10和PD-L1与具侵袭性的临床病理特征相关。SKP2、SOX10及TIL表达与TNBC预后相关,提示这些生物指标可能成为TNBC新的预后因子,同时它们也有可能成为潜在的治疗靶点。

Liver expression of steroid hormones and Apolipoprotein D receptors in hepatocellular carcinoma

AIM: To evaluate the tissular expression of Androgen (A), Estrogen (E) and Progesterone (Pg) receptors, and Apolipoprotein D (ApoD), in liver tumors from resected hepatocellular carcinoma (HCC) cases in order to assess their possible relationship to prognosis. METHODS: We performed an immunohistochemical study using tissue microarrays (containing more than 260 cancer specimens, from 31 HCC patients and controls) to determine the presence of specif ic antibodies against AR, ER, PgR and ApoD, correlating their findings with several clinico-pathological and biological variables. The staining results were categorized using a semi-quantitive score based on their intensity, and the percentage of immunostained cells was measured. RESULTS: A total of 21 liver tumors (67.7%) were positive for AR; 16 (51.6%) for ER; 26 (83.9%) for PgR and 12 (38.7%) stained for ApoD. We have found a wide variability in the immunostaining score values for each protein, with a median (range) of 11.5 (11.5-229.5) for AR; 11.1 (8.5-65) for ER; 14.2 (4-61) for PgR; and 37.7 (13.8-81.1) for ApoD. A history of heavy ethanol consumption, correlated positively with AR and PgR and negatively with ER status. HCV chronic infection also correlated positively with AR and PgR status. However, the presence of ApoD immunostaining did not correlate with any of these variables. Tumors with a positive immuno-staining for PgR showed a better prognosis. CONCLUSION: Our results indicate a moderate clinical value of the steroid receptor status in HCC, emphasizing the need to perform further studies in order to evaluate the possible role of new hormonal-based therapies.

Expression of androgen receptor target genes in skeletal muscle

We aimed to determine the mechanisms of the anabolic actions of androgens in skeletal muscle by investigating potential androgen receptor （AR）-regulated genes in in vitro and in vivo models. The expression of the myogenic regulatory factor myogenin was significantly decreased in skeletal muscle from testosterone-treated orchidectomized male mice compared to control orchidectomized males, and was increased in muscle from male AR knockout mice that lacked DNA binding activity （AR△ZF2） versus wildtype mice, demonstrating that myogenin is repressed by the androgen/AR pathway. The ubiquitin ligase Fbxo32 was repressed by 12 h dihydrotestosterone treatment in human skeletal muscle cell myoblasts, and c-Myc expression was decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle, and increased in AR△ZF2 muscle. The expression of a group of genes that regulate the transition from myoblast proliferation to differentiation, Tceal7, p57Kip2, IEf2 and calcineurin Aa, was increased in AR△ZF2 muscle, and the expression of all but p57kip2 was also decreased in testosterone-treated orchidectomized male muscle compared to control orchidectomized male muscle. We conclude that in males, androgens act via the AR in part to promote peak muscle mass by maintaining myoblasts in the proliferative state and delaying the transition to differentiation during muscle growth and development, and by suppressing ubiquitin ligase-mediated atrophy pathways to preserve muscle mass in adult muscle.

Sex Hormones and Androgen Receptor:Risk Factors of Coronary Heart Disease in Elderly Men

Objective To investigate the variation of sex hormone and its receptor level in elderly male patients with coronary heart disease (CHD) and to evaluate the correlations between CHD and sex hormone as well as sex hormone receptor. Methods Altogether 139 male CHD patients (CHD group) aged 60-92 years and 400 healthy men (control group) aged 60-90 years were included in this cross sectional study. The plasma concentrations of dehydroepiandrosterone sulfate (DHEAS),total testosterone (TT),free testosterone (FT),estradiol (E2),sex hormone binding globulin (SHBG),luteinizing hormone (LH),and follicle-stimulating hormone (FSH) were measured. The androgen receptor (AR) was tested by flow cytometry. Correlations between CHD and levels of sex hormones and AR were analyzed. Results Compared with the control group,the levels of DHEAS,TT,FT,SHBG,and the fluorescence intensity of AR in the CHD group significantly reduced (P<0.05),while the levels of FSH and E2 significantly increased (P<0.01). Age was negatively correlated with TT (r=-0.28,P=0.00) and FT (r=-0.17,P=0.01),while it was positively correlated with SHBG (r=0.14,P=0.04) and E2 (r=0.33,P=0.00). AR fluorescence intensity was negatively correlated with systolic blood pressure (r=-0.12,P=0.01). Binary logistic regression analysis showed that TT,SHBG,and AR were all negatively correlated with CHD (P<0.05). Conclusions Elderly male patients with CHD are found to have low levels of DHEAS,TT,FT,SHBG,and AR,while high concentrations of E2 and FSH. Low levels of TT and SHBG may be the potential risk factors of CHD in elderly men.

Bulbocavernosus muscle area measurement： a novel method to assess androgenic activity

Serum testosterone does not correlate with androgen tissue activity, and it is critical to optimize tools to evaluate such activity in males. Ultrasound measurement of bulbocavernosus muscle （BCM） was used to assess the relationship between the number of CAG repeats （CAGn） in the androgen receptor （AR） and the BCM size; the changes in the number of CAGn over age were also evaluated. Transperineal ultrasound measurement of the BCM was also performed. AR CAGn were determined by high performance liquid chromatography, and morning hormone levels were determined using immunoassays. Forty-eight men had CAG repeat analysis. Twenty-five were 〈30 years of age, mean 23.7 years （s.d, = 3.24） and 23 were 〉45 years of age, mean 53years （s.d. = 5.58）. The median CAGn was 21 （13-29）. BCM area was greater when the number of CAGn were 〈18 as compared to the number of CAGn 〉24 （P= 0.04）. There was a linear correlation between the number of CAGn and the BCM area R^2= 16% （P= 0.01）. In the 45 to 65-years-old group, a much stronger negative correlation （R^2 = 29%, P= 0.01） was noticed. In the 19 to 29-years-old group, no such correlation was found （R2 = 4%, P = 0.36）. In older men, the number of CAGn increased with age （R^2 = 32%, P= 0.01）. The number of CAGn in the AR correlates with the area of the BCM. Ultrasound assessment of the BCM is an effective surrogate to evaluate end-organ activity of androgens. The number of CAGn may increase with age.

Therapeutic targeting of the androgen receptor(AR)and AR variants in prostate cancer

Prostate cancer(PCa)accounted for over 300000 deaths world-wide in 2018.Most of the PCa deaths occurred due to the aggressive castration-resistant PCa(CRPC).Since the androgen receptor(AR)and its ligands contribute to the continued growth of androgendependent PCa(ADPCa)and CRPC,AR has become a well-characterized and pivotal therapeutic-target.Although AR signaling was identified as therapeutic-target in PCa over five-decades ago,there remains several practical issues such as lack of antagonist-bound AR crystal structure,stabilization of the AR in the presence of agonists due to N-terminus and C-terminus interaction,unfavorable large-molecule accommodation of the ligand-binding domain(LBD),and generation of AR splice variants that lack the LBD that impede the discovery of highly potent fail-safe drugs.This review summarizes the AR-signaling pathway targeted therapeutics currently used in PCa and the approaches that could be used in future ARtargeted drug development of potent next-generation molecules.The review also outlines the discovery of molecules that bind to domains other than the LBD and those that inhibit both the full length and splice variant of ARs.

Androgen receptors expressed by prostatic stromal cells obtained from younger versus older males exhibit opposite roles in prostate cancer progression

Aging is a major risk factor for prostate cancer （PCa）, and prostatic stromal cells may also promote PCa progression. Accordingly, stromal cells do not equally promote PCa in older males and younger males. Therefore, it is also possible that the expression of androgen receptors （ARs） by prostatic stromal cells in older versus younger males plays different roles in PCa progression. Using a gene knockdown technique and coculture system, we found that the knockdown of the AR in prostatic stromal cells obtained from younger males could promote the invasiveness and metastasis of cocultured PC3/LNCaP cells in vitro. By contrast, the invasiveness and metastasis of LNCaP cells was inhibited when cocultured with prostatic stromal cells from older males that when AR expression was knocked down. Moreover, after targeting AR expression with small hairpin RNA （shRNA）, matrix metalloproteinase （MMP） expression in stromal cells was observed to increase in the younger group, but decreased or remained unchanged in the older group. One exception, however, was observed with MMP9. In vivo, after knocking down AR expression in prostatic stromal cells, the incidence of metastatic lymph nodes was observed to increase in the younger age group, but decreased in the older age group. Together, these data suggest that the AR in prostatic stromal cells played opposite roles in PCa metastasis for older versus younger males. Therefore, collectively, the function of the AR in prostatic stromal cells appears to change with age, and this may account for the increased incidence of PCa in older males.

Inhibitory Effects of Cypermethrin on Interactions of the Androgen Receptor with Coactivators ARA70 and ARA55

Objective The purpose of this study was to investigate the anti-androgenic mechanism of cypermethrin involving coactivators.Methods Mammalian two-hybrid assays were performed to study the effects of cypermethrin on interactions of the androgen receptor(AR)with the coactivators androgen receptor-associated protein70(ARA70)and androgen receptor-associated protein 55(ARA55).Results The results showed that AR–ARA70 and AR–ARA55 interactions were remarkably enhanced by dihydrotestosterone(DHT,P≤0.05).Cypermethrin inhibited DHT-induced AR–ARA70 and AR–ARA55 interactions significantly(P≤0.05).Conclusion The study indicates that cypermethrin exhibits inhibitory effects on AR transcription associated with repression of AR–ARA70 and AR–ARA55 interactions in a ligand-dependent manner.The data show novel anti-androgenic mechanisms of cypermethrin that contribute to male reproductive toxicology.

Isolated micropenis reveals partial androgen insensitivity syndrome confirmed by molecular analysis

Partial androgen insensitivity syndrome （PAIS） is the milder variant of androgen receptor （AR） defects. The subtle effects of AR mutations present in a patient with micropenis, peno-scrotal hypospadias, infertility, clitoromegaly and posterior labial fusion. We studied the association of isolated micropenis with the genetic defects resulting in androgen resistance, that is, AR gene defects and 5-α reductase type 2 （SRD5A2） deficiency. We describe two cases of isolated micropenis： one in a 14-year-old boy and the other in a 3-year-old boy who was followed until he was 10 years old. There were no findings of hypospadias, cryptorchidism or gynecomastia in either of these patients. Serum gonadotrophin and androgen levels were obtained and karyotyping was done. Human chorionic gonadotropin （hCG） stimulation testing assessed the functional capacity of the testes. DNA was extracted from peripheral leukocytes, and all exons of the SRD5A2 and AR genes were amplified by polymerase chain reaction and sequenced. In both patients, baseline testosterone （T） level was low and the values were elevated after hCG testing. The sequence of the SRD5A2 gene was normal in patient 1, and a heterozygous polymorphism, V89L, was found in patient 2. Two known mutations, P390S and A870V, were identified in patients 1 and 2, respectively. Mutations in the AR gene can be associated with isolated micropenis without other features of PAIS, such as hypospadias or gynecomastia. This underlines the importance of including AR gene analysis in the evaluation of isolated micropenis with normal plasma T to ensure proper management of the patient and appropriate genetic counseling for the family.