雄激素和雄激素受体对肝癌细胞株PEG10表达的作用

目的 探讨雄激素和雄激素受体(AR)对肝癌细胞株PEG10表达的调控作用.方法 设计合成针对人ARsiRNA,并转染HepG2和7404肝癌细胞株.用双氢睾丸酮(DHT)干预HepG2细胞.Western Blot检测AR和PEG10表达水平.结果 从3对AR siRNA中筛选到1对siRNA(AR siRNA-3),它在2种肝癌细胞株中均可有效抑制AR的表达,其抑制作用呈剂量依赖关系.2种肝癌细胞株中,浓度为240 nmol/L的AR siRNA-3在转染后24 h,对AR抑制效率可达80%以上,且抑制效果可持续至72 h.AR siRNA-3转染24h后PEG10表达水平降低,转染48 h后,PEG10表达水平降低非常明显,72 h后PEG10表达有所上升.DHT可促进HepG2细胞PEG10的表达,呈剂量依赖关系.DHT对AR表达未见明显作用.结论 雄激素和AR参与了肝癌细胞株PEG10表达的调控.这可能是男性肝细胞癌发病率较高的原因之一.     

Infertility with defective spermatogenesis and steroidogenesis in male mice lacking androgen receptor in Leydig cells

Androgen and the androgen receptor (AR) have been shown to play critical roles in male fertility. Our previous data demonstrated that mice lacking AR (AR^−/y) revealed incomplete germ cell development and lowered serum testosterone levels, which resulted in azoospermia and infertility. However, the consequences of AR loss in Leydig cells remain largely unknown. Using a Cre-LoxP conditional knockout strategy, we generated a tissue-specific knockout mouse (L-AR^−/y) with the AR gene deleted by the anti-Müllerian hormone receptor-2 (Amhr2) promoter driven Cre expressed in Leydig cells. Phenotype analyses show that the outside appearance of L-AR^−/y mice was indistinguishable from wild type mice (AR^+/y), but with atrophied testes and epididymis. L-AR^−/y mice were infertile, with spermatogenic arrest predominately at the round spermatid stage and no sperm could be detected in the epididymis. L-AR^−/y mice also have lower serum testosterone concentrations and higher serum leuteinizing hormone and follicle-stimulating hormone concentrations than AR^+/y mice. Further mechanistic studies demonstrated that hypotestosteronemia in L-AR^−/y mice is not caused by reducing numbers of Leydig cells, but instead by the alterations of several key steroidogenic enzymes, including 17β-HSD3, 3β-HSD6, and P450c17. Together, L-AR^−/y mice provide in vivo evidence that functional AR in Leydig cells is essential to maintain normal spermatogenesis, testosterone production, and required for normal male fertility. Qingquan Xu, Hung-Yun Lin, and Shauh-Der Yeh contributed equally to this study.     

The role of androgens and the androgen receptor in cycling endometrium

Androgens and the androgen receptor (AR) are not only required for male reproductive function, they are also essential for female reproductive physiology. Widely expressed in female reproductive tissues, AR levels fluctuate in a regulated manner in the cycling endometrium. Female androgen production depends on the adrenal glands and expression of key enzymes in the endometrium that facilitate local androgen biosynthesis and conversion. Moreover, levels of circulating androgens, in women of reproductive age, fluctuate in a cycle-dependent manner and a mid-cycle peak is associated with conception. AR and androgen signalling have a decisive role in the differentiation of human endometrial stromal cells into decidual cells. Compelling evidence for androgen signalling in the regulation of endometrial function pertaining to implantation and pregnancy is provided by epidemiological studies demonstrating a strong association between polycystic ovary syndrome, premature ovarian failure or advanced maternal age and adverse pregnancy outcome. Thus, androgen signalling is an essential component of normal endometrial physiology and its perturbation is associated with reproductive failure.     

Growth hormone (GH) receptors in prostate cancer: gene expression in human tissues and cell lines and characterization, GH signaling and androgen receptor regulation in LNCaP cells

Various hormones and growth factors have been implicated in progression of prostate cancer, but their role and the underlying molecular mechanism(s) involved remain poorly understood. In this study, we investigated the role of human growth hormone (GH) and its receptor (GHR) in human prostate cancer. We first demonstrated mRNA expression of GHR and of its exon 9-truncated isoform (GHR_tr) in benign prostate hyperplasia (BPH) and prostate adenocarcinoma patient tissues, as well as in LNCaP, PC3 and DU145 human prostate cancer cell lines. GHR mRNA levels were 80% higher and GHR_tr only 25% higher, in the carcinoma tissues than in BPH. Both isoforms were also expressed in LNCaP and PC3 cell lines and somewhat less so in DU145 cells. The LNCaP cell GHR protein was further characterized, on the basis of its M_r of 120 kDa, its binding to two different GHR monoclonal antibodies, its high affinity and purely somatogenic binding to ¹²⁵I-hGH and its ability to secrete GH binding protein, all characteristic of a functional GHR. Furthermore, GH induced rapid, time- and dose-dependent signaling events in LNCaP cells, including phosphorylation of JAK2 tyrosine kinase, of GHR itself and of STAT5A (JAK2-STAT5A pathway), of p42/p44 MAPK and of Akt/PKB. No effect of GH (72 h) could be shown on basal or androgen-induced LNCaP cell proliferation nor on PSA secretion. Interestingly, however, GH caused a rapid (2–12 h) though transient striking increase in immunoreactive androgen receptor (AR) levels (≤5-fold), followed by a slower (24–48 h) reduction (≤80%), with only modest parallel changes in serine-phosphorylated AR. In conclusion, the GH-induced activation of signaling pathways, its effects on AR protein in LNCaP cells and the isoform-specific regulation of GHR in prostate cancer patient tissues, suggest that GH, most likely in concert with other hormones and growth factors, may play an important role in progression of human prostate cancer.     

Correlation study between the polymorphism of repetitive sequence in gene CAG of androgen receptor and the occurrence and progression of prostate cancer

Objective:To explore the relation between the polymorphism of repetitive sequence in gene CAG of androgen receptor(AR)and the susceptibility and clinical stages as well as pathological grading of prostate cancer among Han population.Method:Sixty-eight cases with prostate cancer hospitalized in Urinary Surgery Department from Feb.2010 to Feb.2012 and 60 healthy cases were chosen as research subjects.Methods of PCR and direct sequencing were adopted to detect DNA sequence of AR gene and the length of repetitive sequence in CAG.Results:The lengths of repetitive sequence in CAG of patients with prostate cancer and healthy people were(22.3±4.6)and(23.0±4.9),respectively showing no statistical significance.Comparing length(repetitive sequence of CAG)22,those with that22 suffer a remarkably higher risk of prostate cancer(P0.05).The number of repetitive sequence in CAG of patients at clinical stage C-D was less than that of patients at stage B,and the number of repetitive sequence in CAG of patients with poorly differentiated prostate cancer was also less than that of patients with moderately and highly differentiated prostate cancer.But there was no statistical significance int the difference(P0.05);the proportion of patients with length22 at clinical stage C-D was much larger than that of patients at clinical stage B(P0.05),and as the aggravation of pathological grading,the proportion of patients with the length22 was also remarkably increased and there was significant difference between patients with highly differentiated prostate cancer and those with poorly differentiated prostate cancer(P0.05).Conclusions:There is correlation between the occurrence and development of prostate cancer in Han population and the polymorphism of repetitive sequence in gene CAG of androgen receptor.The less the number of repetitive sequence in CAG is,the higher the risk of prostate cancer will be and the more severe the clinical stage and pathological grading will be.     

Up-regulation of the levels of androgen receptor and its mRNA by androgens in smooth-muscle cells from rat penis

Smooth-muscle cells cultured from the penis of sexually immature (I-PSMC) and adult (A-PSMC) rats express similar high levels of the androgen receptor (AR) mRNA. This contrasts with the marked in vivo decline of both AR mRNA and androgen binding in the penile smooth muscle of adult rats, which appears to be responsible for the cessation of androgen-dependent penile growth upon sexual maturation. PSMC is therefore a good model to study down-regulators of AR expression as a function of cell proliferation in the smooth muscle of androgen-reputative sponsive vascular tissue. In order to determine whether AR protein levels in PSMC correlate with AR mRNA levels, the immunocytochemical detection of ARs and their androgen binding capacity were compared between I- and A-PSMC. The number of ARs and their protein half-lives suggested similar levels of translation of the AR mRNA in both cell lines. The effect of the synthetic analog methyltrienolone (R-1881) on androgen binding was studied in contact-inhibited androgen-deprived PSMC. In contrast to the postulated role of androgens as down-regulators of AR expression in rat penis, ARs were up-regulated in A-PSMC by R-1881. Contact inhibition of A-PSMC combined with serum depletion and androgen deprivation down-regulated AR mRNA levels, and dihydrotestosterone (DHT) counteracted this effect. These results suggest that the loss in A-PSMC of the age-dependent down-regulation of ARs observed in vivo in adult corpora cavernosa smooth muscle is related to the in vitro resumption of cell proliferation and that DHT acts directly on the penile smooth muscle as a positive modulator of AR levels.     

Androgen receptor amplification is reflected in the transcriptional responses of Vertebral-Cancer of the Prostate cells

Androgen receptor (AR) is overexpressed in a majority of castration-resistant prostate cancers, but most of the cell model studies addressing AR function have been conducted in LNCaP prostate cancer cells expressing unamplified AR levels. Here, we have compared the responses of various types of AR ligands towards a pattern of AR target genes and chromatin binding sites in Vertebral-Cancer of the Prostate (VCaP) cells and LNCaP cells. In keeping with the AR gene amplification in VCaP cells, our analyses show that these cells contain ≥10-fold receptor mRNA and protein than LNCaP cells. Loading of the agonist-occupied AR onto chromatin regulatory sites and expression of several AR target genes, including their basal expression, were stronger in VCaP cells than LNCaP cells. Bicalutamide displayed a trend towards agonism in VCaP cells. Bicalutamide also evoked AR–chromatin interaction, whereas diarylthiohydantoin antiandrogen RD162 was inert with this respect both in VCaP and LNCaP cells. These results support the notion that the AR protein level translates into augmented occupancy of AR-regulated enhancers and target gene activity in prostate cancer cells.     

Tandem CAG repeats of the androgen receptor gene and prostate cancer risk in black and white men

The most common malignancy in men worldwide is cancer of the prostate. Androgens play a direct role in normal and malignant growth of prostate cells via the androgen receptor (AR). This study analyzed the polymorphic CAG repeat sequence in exon 1 of the AR gene to determine if the number of repeats might be an indicator of prostate cancer risk or aggressive disease. DNA was extracted from blood samples of 20 black and 20 white men with well-documented prostate cancer and 40 healthy, controls (20 blacks and 20 whites). PCR amplifications was followed by gel electrophoresis and DNA sequencing. This region normally contains between 9 and 29 repeats. Patients and controls both had minor variations in the number of repeats, which ranged from 13 to 27 with 21 being the most frequent allele. Black controls and patients both had a mean of 20±3, repeats; in whites the mean was significantly lower in patients than controls (21±2 versus 23±2; p=0.004). Combined black and white patients also had a lower number than the combined group of controls (20±3 versus 22±3; p=0.02). Similarly, black and white patients with aggressive disease has a lower number than patients whose disease was more slowly progressive (19±2 versus 22±3; p=0.02). We conclude that the small differences in the number of CAG repeats in both black and white patients do not appear to be a strong indicator of risk or aggressive disease but that this size polymorphism may be one of many genetic and environmental risk factors involved in prostate cancer.     

Interaction of androgen and glucocorticoid receptor DNA-binding domains with their response elements

Fusion proteins containing the glucocorticoid and the androgen receptor DNA-binding domain (ARF1 and GRF1) were produced in Escherichia coli. DNAse I footprinting was used to compare the interaction of these proteins with responsive elements (REs) in a typically glucocorticoid-responsive gene (mouse mammary tumour virus (MMTV)) and in an androgen-responsive gene (the C3(l) gene of rat prostatic binding protein). It is demonstrated that response elements which most closely resemble the consensus sequence show identical footprinting patterns for ARF1 and GRF1. The protected regions suggest that these sequences are occupied by two DNA-binding domains (DBDs) forming a dimer. Regions that constitute imperfect RE sequences, however, are apparently recognized by only one DBD, which mainly protects the TGTTCT motif. At these REs, the protection patterns produced by ARF1 and GRF1 are not identical. In the long terminal repeat (LTR) of MMTV but not in C3(1), a mechanism other than classical dimer formation seems to increase the affinity of ARF1 and GFR1 for these imperfect REs.     

再生障碍性贫血雄激素受体与T细胞亚群的变化

目的:检测慢性再生障碍性贫血(CAA)患者骨髓单个核细胞(MNC)雄激素受体(AR)以及骨髓中T细胞亚群水平,探讨AR在CAA免疫病理机制中的作用。方法:①免疫细胞化学SP法检测CAA患者骨髓MNC内AR的表达水平;②流式细胞术检测CAA骨髓中T细胞亚群(CD3 CD4 细胞、CD3 CD8 细胞)的含量。结果:①CAA患者骨髓MNC中AR阳性水平[(35．18±8．78)个／200个MNC]显著低于对照组[(48．46±9．82)个／200个MNC];不同性别间AR的含量差异无统计学意义。②CAA患者骨髓中的CD3 CD8 细胞含量为(28．54±7．57)％,显著高于对照组。③CAA患者骨髓中的AR阳性水平与骨髓中的CD3 CD8 细胞呈负相关(r=-0．576,P<0．01);而与CD3 CD4 细胞含量未见明显的直线相关关系。结论:CAA患者骨髓AR的表达减少,从而使雄激素刺激造血的作用减弱。患者AR的表达与CD3 CD8 细胞含量呈明显负相关,表明AR的异常可能在一定程度上参与了CAA发病机制中的细胞免疫。     

Androgen receptor signalling in prostate: effects of stromal factors on normal and cancer stem cells

The prostate gland is the most common site for cancer in males within the developed world. Androgens play a vital role in prostate development, maintenance of tissue function and pathogenesis of prostate disease. The androgen receptor signalling pathway facilitates that role in both the epithelial compartment and in the underlying stroma. Stroma is a key mediator of androgenic effects upon the epithelium and can regulate both the fate of the epithelial stem cell and potentially the initiation and progression of prostate cancer. Different groups of growth factors are expressed by stroma, which control proliferation, and differentiation of prostate epithelium demonstrating a critical role for stroma in epithelial growth and homeostasis. Paracrine stromal proteins may offer the possibility to control tumour stem cell growth and could permit prostate specific targeting of both therapies and of androgen responsive proteins. The effect of 5alpha-dihydrotestosterone, the more potent metabolite of testosterone, on expression of androgen-regulated genes in stroma from benign prostatic hyperplasia is a key mediator of epithelial cell fate. Global gene expression arrays have recently identified new candidate genes in androgen responsive stroma, some of which have androgen receptor binding sites in their promoter regions. Some of these genes have direct androgen receptor binding ability.     

Combined profile of the tandem repeats CAG, TA and CA of the androgen and estrogen receptor genes in breast cancer

Purpose Case–control studies have reported inconsistent results concerning the association between polymorphisms in the androgen and estrogen receptor (ER) genes and breast cancer. While several studies investigated the association between the androgen receptor (AR) gene, CAG repeat and breast cancer, for the CA and TA repeats in the ER genes there are considerably fewer studies (one for CA and none for TA).Methods We have investigated the potential link between three tandem repeats (CAG, TA, and CA) in the AR, ERs α and β genes, respectively, and breast cancer. DNA was isolated from 153 invasive breast tumors and 318 controls, and the three tandem repeats were sized by polyacrylamide electrophoresis. Number of repeats in each allele and the total repeats of both alleles were taken as variables for classification into dichotomous groups using the median of each variable in the control group as cut-off point. Relationship between polymorphic tandem repeats and breast cancer was assessed by multivariate logistic regression models.Results Three variables combined, longer CAGsum (≥28), shorter TA (<23) and CA (<23) repeats could constitute a possible genetic profile associated with breast cancer.Conclusions Our results confirm previous reports regarding an association between longer CAG repeats and breast cancer. In addition to that, we found that the combination of long CAG, short TA and CA repeats are strongly associated with breast cancer.This paper was initially submitted with an additional co-author who withdrew the co-authorship during the review process. All listed authors have now signed that they agree with the content of the current paper.