Co-expression Of Androgen Receptor Research Articles

Coordinated expression of oestrogen and androgen receptors in HER2-positive breast carcinomas: impact on proliferative activity

AimsHuman epidermal growth factor receptor 2 (HER2)-positive breast cancers are aggressive neoplasms associated with a variable response to systemic therapies. Therefore, the identification of biomarkers to better characterise this heterogeneity...

Sex- and age-related differences in ribosomal proteins L17 and L37, as well as androgen receptor protein, in the song control system of zebra finches

The zebra finch song system is sexually dimorphic—only males sing, and the morphology of forebrain regions controlling the learning and production of this song is greatly enhanced in males compared to females. Masculinization appears to involve effects of steroid hormones as well as other factors, perhaps including the expression of sex chromosome genes (males: ZZ, females: ZW). The present study investigated three proteins—two encoded by Z-linked genes, ribosomal proteins L17 and L37 (RPL17 and RPL37), including their co-localization with androgen receptor (AR), from post-hatching day 25 to adulthood. Extensive co-expression of AR with the ribosomal proteins was detected in the three song nuclei investigated (HVC, robust nucleus of the arcopallium (RA), and Area X) across these ages. In general, more cells expressed each of these proteins in males compared to females, and the sex differences increased as animals matured. Specific patterns differed across regions and between RPL17 and RPL37, which suggest potential roles of one or both of these proteins in the incorporation and/or differentiation of song system cells.

630 Prospective cloning of functionally distinct breast cancer cells by use of markers from a normal human breast lineage hierarchy

GATA-binding protein 3 (GATA3) is a diagnostically useful immunohistochemical marker of breast cancer. Because of its strong association with estrogen receptor expression, GATA3 has markedly reduced sensitivity in triple-negative breast cancer (TNBC). We constructed a tissue microarray using a large series of TNBCs and evaluated GATA3 expression by TNBC subtype as defined by surrogate immunohistochemical markers. A total of 205 TNBCs were classified into cancers of the molecular apocrine type (n = 23, 11.2%), claudin-low type (n = 21, 10.2%), basal-like type (n = 91, 44.4%), mixed type (n = 62, 30.2%), and null type (n = 8, 3.9%). The GATA3 scores (staining intensity × proportion) were categorized as negative (0), focally positive (1-10), or positive (11-300). GATA3 staining was negative in 153 cancers (74.6%), focally positive in 11 (5.4%), and positive in 41 (20.0%). The rate of focal positivity or positivity for GATA3 was significantly higher in the molecular apocrine type (73.9%, 17/23) than in other types of TNBCs (P = .001). The mean GATA3 score of molecular apocrine–type TNBC was significantly higher than that of the other types (P = .001) and differed significantly between androgen receptor (AR)–positive and AR-negative TNBCs (P < .001). In conclusion, GATA3 expression was correlated strongly with AR-positive, molecular apocrine–type TNBCs. Co-expression of AR and GATA3 is a specific feature of molecular apocrine–type TNBC, which may serve as a diagnostic aid for cancer of unknown primary.

Predictive Value of PTEN and AR Coexpression of Sustained Responsiveness to Hormonal Therapy in Prostate Cancer—A Pilot Study

One limitation of current biochemical or histologic analysis of advanced prostate cancer (PC; T3/T4 ±Nx Mx) is the ability to identify on first diagnostic biopsy patients who will make a durable response to hormone ablation therapy. The aim of this study was to assess the predictive value (sustained response to hormonal therapy and clinical outcome (relapse-free and overall survival)) of phosphatase and tensin homolog (PTEN) and the androgen receptor (AR) immunoexpression in the presenting biopsy. Analysis was performed on 47 samples (10 cases of benign prostatic hyperplasia and 37 hormone-naive PCs). Patients selected represented two stages in the natural history of PC: The “clinical metastatic androgen–responsive” (androgen-dependent PC, ADPC) and the “clinical metastatic androgen–resistant” (androgen-independent PC, AIPC). Reduced immunoreactivity (IR) of either or both PTEN/AR in the initial hormone-naive PC samples was observed with increased frequency in AIPCs. In the ADPC group, low PTEN and/or AR-IR was associated with a shorter median relapse-free survival, i.e., at 30 months after surgery, the probability of relapse-free survival for high expressors of PTEN and AR was 85.7% (SEM = 9.3) compared with only 16.6% (SEM = 15.2) in low expressors. At 36 months, only 28.5% (SEM = 9.3) of ADPC high expressors had experienced a biochemical relapse compared with 100% of low expressors (hazard ratio, 4.6; 95% confidence interval, 4.7-146.8). Further studies analyzing the coexpression of PTEN and AR should be undertaken to validate this pilot study and the utility of these biomarkers in routine histopathologic workup of patients with PC.

Broadening of transgenic adenocarcinoma of the mouse prostate (TRAMP) model to represent late stage androgen depletion independent cancer

The transgenic adenocarcinoma of the mouse prostate (TRAMP) model closely mimics PC-progression as it occurs in humans. However, the timing of disease incidence and progression (especially late stage) makes it logistically difficult to conduct experiments synchronously and economically. The development and characterization of androgen depletion independent (ADI) TRAMP sublines are reported. Sublines were derived from androgen-sensitive TRAMP-C1 and TRAMP-C2 cell lines by androgen deprivation in vitro and in vivo. Epithelial origin (cytokeratin) and expression of late stage biomarkers (E-cadherin and KAI-1) were evaluated using immunohistochemistry. Androgen receptor (AR) status was assessed through quantitative real time PCR, Western blotting, and immunohistochemistry. Coexpression of AR and E-cadherin was also evaluated. Clonogenicity and invasive potential were measured by soft agar and matrigel invasion assays. Proliferation/survival of sublines in response to androgen was assessed by WST-1 assay. In vivo growth of subcutaneous tumors was assessed in castrated and sham-castrated C57BL/6 mice. The sublines were epithelial and displayed ADI in vitro and in vivo. Compared to the parental lines, these showed (1) significantly faster growth rates in vitro and in vivo independent of androgen depletion, (2) greater tumorigenic, and invasive potential in vitro. All showed substantial downregulation in expression levels of tumor suppressor, E-cadherin, and metastatis suppressor, KAI-1. Interestingly, the percentage of cells expressing AR with downregulated E-cadherin was higher in ADI cells, suggesting a possible interaction between the two pathways. The TRAMP model now encompasses ADI sublines potentially representing different phenotypes with increased tumorigenicity and invasiveness.

Expression of Androgen Receptor by Fibroepithelioma of Pinkus: Evidence Supporting Classification as a Basal Cell Carcinoma Variant?

The classification of fibroepithelioma of Pinkus as basal cell carcinoma or trichoblastoma remains controversial. Immunohistochemical stains for androgen receptor may be useful in differentiating basal cell carcinoma from trichoepithelioma or trichoblastoma. We studied androgen receptor expression in 13 fibroepitheliomas of Pinkus, 11 basal cell carcinomas, 12 trichoepitheliomas, and 3 trichoblastomas. Androgen receptor expression was present in 77% (10/13) of fibroepitheliomas of Pinkus, 73% (8/11) of basal cell carcinomas, 17% (2/12) of trichoepitheliomas, and 0% (0/3) of trichoblastomas. Androgen receptor expression was significantly higher in fibroepitheliomas of Pinkus compared with trichoepitheliomas and trichoblastomas (P = .0007), but not basal cell carcinoma (P = 1.00). Tumor-associated Merkel cells, a feature of benign follicular tumors, was identified by cytokeratin 20 stains. Merkel cells were identified in 85% (11/13) of fibroepitheliomas of Pinkus, 27% (3/11) of basal cell carcinoma cases, and 73% (11/15) of benign follicular tumors. Cytokeratin 20 expression was significantly higher in fibroepithelioma of Pinkus and benign follicular tumors compared with basal cell carcinomas (P = 0.0111 and P = 0.025, respectively). No significant difference was found between fibroepitheliomas of Pinkus and trichoepitheliomas and trichoblastomas (P = 1.00). Similar to basal cell carcinomas, fibroepitheliomas of Pinkus express androgen receptors, potentially supporting classification as a basal cell carcinoma. Conversely, fibroepithelioma of Pinkus demonstrates retention of Merkel cells, a feature of benign follicular tumors. Immunophenotypic evidence for the classification of fibroepithelioma of Pinkus remains inconclusive. In small, partial biopsy specimens, coexpression of androgen receptor and cytokeratin 20 may aid in the diagnosis of fibroepithelioma of Pinkus.

Nuclear Compartmentalization of N-CoR and Its Interactions with Steroid Receptors

The repression mechanisms by the nuclear receptor corepressor (N-CoR) of steroid hormone receptor (SHR)-mediated transactivation were examined. Yellow fluorescent protein (YFP)-N-CoR was distributed as intranuclear discrete dots, while coexpression of androgen receptor (AR), glucocorticoid receptor alpha, and estrogen receptor alpha ligand-dependently triggered redistribution of YFP-N-CoR. In fluorescence recovery after photobleaching analysis, mobility of the N-CoR was reduced by 5alpha-dihydrotestosterone (DHT)-bound AR. The middle region of N-CoR mostly contributed to the interaction with agonist-bound SHRs and the suppression of their transactivation function. N-CoR impaired the DHT-induced N-C interaction of AR, and the impaired interaction was dose-dependently recovered by coexpression of SRC-1 and CBP. N-CoR also impaired the intranuclear complete (distinct) focus formation of SHRs. Coexpression of SRC-1 or CBP released YFP-N-CoR or endogenous N-CoR from incomplete foci and simultaneously recovered complete foci of AR-green fluorescent protein. These results indicate that the relative ratio of coactivators and corepressors determines the conformational equilibrium between transcriptionally active and inactive SHRs in the presence of agonists. The intranuclear foci formed by agonist-bound SHRs were completely destroyed by actinomycin D and alpha-amanitin, indicating that the focus formation does not precede the transcriptional activation. The focus formation may reflect the accumulation of SHR/coactivator complexes released from the transcriptionally active sites and thus be a mirror of transcriptionally active complex formation.

Androgen receptors are frequently expressed in mammary and extramammary Paget's disease

Mammary Paget’s disease and extramammary Paget’s disease are rare intraepithelial neoplasms. Mammary Paget’s disease is almost exclusively associated with underlying invasive breast carcinoma or high-grade ductal carcinoma in situ (DCIS G3). Extramammary Paget’s disease arises in areas rich in apocrine glands and is suspected to have apocrine gland origin. The aim of the study was to investigate the presence of estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR) and Her2/neu in a large number of cases. We investigated 58 cases of mammary and 23 cases of extramammary Paget’s disease. Formalin-fixed and paraffin-embedded tissues were analyzed using antibodies against AR, PR, ER and Her2/neu according to standardized procedures. In mammary Paget’s disease, positive immunoreactions for Her2/neu, AR and ER were observed in 56 of 58 (97%), 51 of 58 (88%), and respectively in six of 58 (10%) cases. All cases of mammary Paget’s disease were negative for PR and showed a coexpression of Her2/neu and AR in 51 out of 58 cases (88%). In extramammary Paget’s disease, positive immunoreactions for AR, Her2/neu and ER were observed in 18 of 23 (78%), 12 of 23 (52%), and respectively in 1 of 23 (4%) cases. All cases of extramammary Paget’s disease were negative for PR and showed a coexpression of AR and Her2/neu in 12 out of 23 cases (52%). In contrast to ER and PR, AR and Her2/neu are commonly expressed in mammary and extramammary Paget’s disease. The knowledge about frequent expression of AR in Paget’s disease could lead to the development of a new adjuvant therapy, particularly in patients with recurrent disease.

Differential Regulation of KiSS-1 mRNA Expression by Sex Steroids in the Brain of the Male Mouse

Kisspeptins are products of the Kiss1 gene, which bind to GPR54, a G protein-coupled receptor. Kisspeptins and GPR54 have been implicated in the neuroendocrine regulation of GnRH secretion. To test the hypothesis that testosterone regulates Kiss1 gene expression, we compared the expression of KiSS-1 mRNA among groups of intact, castrated, and castrated/testosterone (T)-treated male mice. In the arcuate nucleus (Arc), castration resulted in a significant increase in KiSS-1 mRNA, which was completely reversed with T replacement, whereas in the anteroventral periventricular nucleus, the results were the opposite, i.e. castration decreased and T increased KiSS-1 mRNA expression. In the Arc, the effects of T on KiSS-1 mRNA were completely mimicked by estrogen but only partially mimicked by dihydrotestosterone, a nonaromatizable androgen, suggesting that both estrogen receptor (ER) and androgen receptor (AR) play a role in T-mediated regulation of KiSS-1. Studies of the effects of T on KiSS-1 expression in mice with either a deletion of the ERalpha or a hypomorphic allele to the AR revealed that the effects of T are mediated by both ERalpha and AR pathways, which was confirmed by the presence of either ERalpha or AR coexpression in most KiSS-1 neurons in the Arc. These observations suggest that KiSS-1 neurons in the Arc, whose transcriptional activity is inhibited by T, are targets for the negative feedback regulation of GnRH secretion, whereas KiSS-1 neurons in the anteroventral periventricular nucleus, whose activity is stimulated by T, may mediate other T-dependent processes.

Molecular characterization of human prostate carcinoma cell lines.

This study presents a comprehensive survey and characterization of available prostate carcinoma cell lines, most of which have been widely used but are incompletely characterized. A total of 21 cell lines were investigated, including three "classical" (DU 145, LNCaP, and PC-3) and 18 "non-classical" lines (1013L, 22Rv1, ALVA-55, ALVA-101, ARCaP, CWR-R1, DuCaP, DuPro-1, LAPC-4, MDA PCa 1, MDA PCa 2a, MDA PCa 2b, NCI-H660, PC-346C, PC-93, PSK-1, UM-SCP-1, and VCaP). Cytogenetics, DNA profiling, expression of basal, luminal, and neuroendocrine differentiation markers, and mutation analyses of the TP53 and androgen receptor (AR) genes were performed. Based on cytogenetics and DNA profiling analyses, out of the 18 "non-classical" lines, six were confirmed to be unique, eight (in four pairs) were confirmed to be related in origin, and four lines were identified as cross-contaminants. Of this latter group, PC-93 was found to be a derivative of HeLa, whereas DuPro-1, ALVA-55, and ALVA-101 were derivatives of PC-3. The 17 genuine prostate cell lines expressed keratin 8 (K8) and K18. Nine showed AR expression, of which five harbored mutations in the AR gene. Prostate-specific antigen and DD3 were exclusively detected in AR expressing cell lines. Seven lines expressed the basal cell marker K5, three of these lines showed co-expression of AR. This study defines a collection of 17 genuine prostate carcinoma cell lines. This collection, although small, constitutes a variety of different types and stages of prostate cancer, while it also partly reflects the heterogeneous nature of this malignancy.

SRY Interacts with and Negatively Regulates Androgen Receptor Transcriptional Activity

This study investigated interactions between SRY, the Y chromosome encoded male sex determining factor, and the androgen receptor (AR). Coexpression of AR and SRY caused marked repression of AR transcriptional activity on a series of androgen-responsive reporter genes. Mammalian one- and two-hybrid experiments demonstrated an AR-SRY interaction mediated by the AR DNA binding domain. Precipitations with glutathione S-transferase fusion proteins indicated that AR-SRY interactions were direct and mediated by the AR DNA binding domain and the SRY high mobility group box DNA binding domain. Transient expression of SRY in LNCaP prostate cancer cells repressed expression of an androgen-dependent prostate-specific antigen (PSA) reporter gene and stable SRY expression repressed the endogenous PSA gene. SRY protein expression was increased by proteosome inhibitors and by the androgen-liganded AR in transient and stable transfectants. AR transcriptional activity was also repressed by DAX1, and the effects of SRY and DAX1 on the AR were additive. These findings indicate that interactions between the AR, SRY, and DAX1 contribute to normal male development and function and suggest a general role for protein-protein interactions between high mobility group box proteins and steroid hormone receptors in regulating tissue-specific gene expression.

Interactions between androgen and estrogen receptors and the effects on their transactivational properties

The physiological interplay of androgen and estrogen action in endocrine tissues is well recognized. The biochemical processes responsible for this interplay have yet to be fully defined. We have demonstrated that the androgen receptor (AR) and estrogen receptor-alpha (ERα) can interact directly using the yeast and mammalian two-hybrid systems. These interactions occurred between the C-terminal ERα ligand-binding domain and either the N-terminal AR transactivational domain or the full-length AR. Estrogen receptor-beta (ERβ) did not interact with the AR. DNA cotransfection studies employing AR, ERα and ERβ expression vectors and AR- or ER-reporter gene constructs were used to identify and measure potential functional effects of AR–ER interaction. Coexpression of ERα with AR decreased AR transactivation by 35%; coexpression of AR with ERα decreased ERα transactivation by 74%. Coexpression of AR and ERβ did not significantly modulate AR or ERβ transactivation. In summary, we have shown that specific domains of AR and ERα physically interact and have demonstrated the functional consequences of such interaction. These results may help explain the nature of the physiological interplay between androgens and estrogens.

Distribution of aromatase, estrogen receptor, and androgen receptor mRNA in the forebrain of songbirds and nonsongbirds

Androgens and estrogens are crucial for the differentiation and function of the vocal control system of songbirds. A major source of estrogens in songbirds is the cerebral aromatization of circulating testosterone by aromatase (ARO). In the vocal control system, songbirds have a unique estrogen receptor (ER)-containing area, the nucleus hyperstriatalis ventrale pars caudale (HVC) of the caudal neostriatum. Work in the zebra finch has demonstrated ARO expression adjacent to but not in the HVC. Compared with other songbirds, such as the canary, the HVC of adult zebra finches contains only few ERs. To determine whether the disjunctive distribution of ERs and ARO in the forebrain is a songbird-specific feature, the authors investigated ARO and ER mRNA expression in songbirds (canary, house sparrow, and zebra finch) and in nonsongbirds (budgerigar, ring dove, swift, grey partridge, and barn owl) of five avian orders. In addition, the coexpression of androgen receptor (AR) and ARO mRNAs was studied. Preoptic hypothalamic areas showed similar expression of ARO in all species. In the caudal neostriatum, ARO, AR, and ER transcripts were found only in songbirds. ARO and ER mRNA expression in the caudal forebrain was spatially separated, i.e., the HVC contained ER mRNA but very little or no ARO mRNA, and the caudomedial neostriatum contained high levels of ARO mRNA but few if any ERs. ARO and AR mRNAs, however, were coexpressed in the caudomedial neostriatum. The coexpression of ARO mRNA with AR mRNA but not with ER mRNA was found in further brain areas, such as the nucleus posterior lateralis hypothalami. The area-specific coexpression of AR, ER, and ARO suggests various possibilities for the steroid-dependent regulation of ARO and for the role of ARO in controlling AR- and ER-dependent mechanisms.

Immunohistochemical study of hormone receptor and hormone-regulated protein expression in phyllodes tumour: comparison with fibroadenoma

The histogenesis of phyllodes tumour (PT) and that of fibroadenoma (FA) of the breast appear to be closely related. FA is thought to be hormonally responsive, while the hormone-responsiveness of PT is uncertain. To gain insight into hormone-responsiveness of PT, we performed immunohistochemical analysis of oestrogen-regulated pS2 and androgen-regulated prostate-specific antigen (PSA) protein expression and also of oestrogen receptor (ER), progesterone receptor (PgR) and androgen receptor (AR) expression in paraffin sections obtained from 50 female PT patients. Paraffin sections taken from 50 female fibroadenoma (FA) patients were analysed for comparison. ER, PgR, pS2, AR and PSA expression were detected in 32%, 96%, 20%, 98% and 4.0% of PT sections and in 28%, 96%, 42%, 80% and 10% of FA sections, respectively. No correlations were detected among ER, PgR and pS2 expression or between AR and PSA expression in PT or FA sections. PgR expression was significantly associated with AR expression in PT (P<0.0001). The present investigations indicate that PT and FA have almost similar hormone receptor status. However, different positivities of pS2 expression suggest that oestrogen-responsiveness may differ between PT and FA. In addition, a wide-ranging co-expression of AR and PgR in PT sections suggests that these receptors may play an important part in the proliferation, although the functional significance of these receptors should be elucidated.