Gene and protein expression of oestrogen-beta and progesterone receptors in facial melasma and adjacent healthy skin in women

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Androgen receptors and experimental bone loss - an in vivo and in vitro study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Epigenetic and oncogenic regulation of SLC16A7 (MCT2) results in protein over-expression, impacting on signalling and cellular phenotypes in prostate cancer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Papel do resveratrol sobra a modulação do receptor Aril-hidrocarboneto (AhR) e o desenvolvimento da próstata de ratos expostos ao 2, 3, 7, 8-tetraclorodibenzo-p-dioxina (TDCC) durante a gestação

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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

Aims Human 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 would improve treatment efficacy. The aim of this study was to evaluate the influence of androgen receptor (AR) and oestrogen receptor (ER) on clinicopathological features in a series of HER2-positive breast carcinomas. Methods A total of 104 carcinomas were selected and reviewed. Immunohistochemical studies for ER, progesterone receptor and Ki-67 were analysed on tumour whole histological sections. AR expression was analysed on samples represented on tissue microarrays. According to steroid receptor expression, cases were classified into three groups: AR positive/ER positive (48 cases), AR positive/ER negative (41 cases) and AR negative/ER negative (13 cases). Results AR-positive tumours corresponded to 89 (85.6%) of 104 carcinomas. AR-positive carcinomas were associated with a higher frequency of ER and progesterone receptor co-expression and lower proliferative activity determined by the expression of Ki-67. AR-negative carcinomas were more often high grade. The group of AR-positive/ER-negative carcinomas was associated with the highest frequency of apocrine morphological features. The group of AR-negative/ER-negative carcinomas was associated with the highest proliferative activity and the highest frequency of high histological and nuclear grade. The lowest frequency of high-grade tumours and the lowest proliferative activity were seen among tumours with expression of both receptors. Conclusions These results suggest that co-expression of AR and ER can provide a protective effect based on phenotypical presentation of HER2-positive carcinomas. Furthermore, lack of both steroid hormone receptors characterises the most aggressive phenotype.

Association of single nucleotide polymorphisms in the bovine leptin and leptin receptor genes with growth and ultrasound carcass traits in Nellore cattle

Given the important role of leptin in metabolism, we looked for a possible association of leptin and leptin receptor polymorphisms with carcass and growth traits in Nellore cattle. We examined associations of leptin and leptin receptor SNPs with ultrasound carcass (longissimus dorsi muscle area (ribeye area), backfat thickness and rump fat thickness and growth traits (weaning weight adjusted to 210 days of age, yearling weight adjusted to 550 days of age, weight gain of weaning to yearling and scrotal circumference adjusted to 550 days of age) of 2162 Bos primigenius indicus (Nellore) animals. Allele and genotypic frequencies were calculated for each marker. Allele substitution, additive and dominance effects of the polymorphisms were also evaluated. Some alleles of the molecular markers had low frequencies, lower than 1%, in the sample analyzed, although the same polymorphisms described for B. p. taurus cattle were found. Due to very low allelic frequencies, the E2JW, A59V and UASMS2 markers were not included in the analysis, because they were almost fixed. E2FB was found to be significantly associated with weight gain, ribeye area and backfat thickness. The promoter region markers, C963T and UASMS1, were also found to be significantly associated with ribeye area. T945M was significantly associated with weight gain. We conclude that the leptin and receptor gene markers would be useful for marker-assisted selection.

Testosterone Induces Vascular Smooth Muscle Cell Migration by NADPH Oxidase and c-Src-Dependent Pathways

Testosterone has been implicated in vascular remodeling associated with hypertension. Molecular mechanisms underlying this are elusive, but oxidative stress may be important. We hypothesized that testosterone stimulates generation of reactive oxygen species (ROS) and migration of vascular smooth muscle cells (VSMCs), with enhanced effects in cells from spontaneously hypertensive rats (SHRs). The mechanisms (genomic and nongenomic) whereby testosterone induces ROS generation and the role of c-Src, a regulator of redox-sensitive migration, were determined. VSMCs from male Wistar-Kyoto rats and SHRs were stimulated with testosterone (10(-7) mol/L, 0-120 minutes). Testosterone increased ROS generation, assessed by dihydroethidium fluorescence and lucigenin-enhanced chemiluminescence (30 minutes [SHR] and 60 minutes [both strains]). Flutamide (androgen receptor antagonist) and actinomycin D (gene transcription inhibitor) diminished ROS production (60 minutes). Testosterone increased Nox1 and Nox4 mRNA levels and p47phox protein expression, determined by real-time PCR and immunoblotting, respectively. Flutamide, actinomycin D, and cycloheximide (protein synthesis inhibitor) diminished testosterone effects on p47phox. c-Src phosphorylation was observed at 30 minutes (SHR) and 120 minutes (Wistar-Kyoto rat). Testosterone-induced ROS generation was repressed by 3-(4-chlorophenyl) 1-(1,1-dimethylethyl)-1H-pyrazolo[3,4-day]pyrimidin-4-amine (c-Src inhibitor) in SHRs and reduced by apocynin (antioxidant/NADPH oxidase inhibitor) in both strains. Testosterone stimulated VSMCs migration, assessed by the wound healing technique, with greater effects in SHRs. Flutamide, apocynin, and 3-(4-chlorophenyl) 1-(1,1-dimethylethyl)-1H-pyrazolo[3,4-day] pyrimidin-4-amine blocked testosterone-induced VSMCs migration in both strains. Our study demonstrates that testosterone induces VSMCs migration via NADPH oxidase-derived ROS and c-Src-dependent pathways by genomic and nongenomic mechanisms, which are differentially regulated in VSMCs from Wistar-Kyoto rats and SHRs. (Hypertension. 2012; 59: 1263-1271.). Online Data Supplement

Genomic and non genomic effects of elevated concentration of anabolic steroids in human neuronal cells

Nandrolone and other anabolic androgenic steroids (AAS) at elevated concentration can alter the expression and function of neurotransmitter systems and contribute to neuronal cell death. This effect can explain the behavioural changes, drug dependence and neuro degeneration observed in steroid abuser. Nandrolone treatment (10-8M–10-5M) caused a time- and concentration-dependent downregulation of mu opioid receptor (MOPr) transcripts in SH-SY5Y human neuroblastoma cells. This effect was prevented by the androgen receptor (AR) antagonist hydroxyflutamide. Receptor binding assays confirmed a decrease in MOPr of approximately 40% in nandrolonetreated cells. Treatment with actinomycin D (10-5M), a transcription inhibitor, revealed that nandrolone may regulate MOPr mRNA stability. In SH-SY5Y cells transfected with a human MOPr luciferase promoter/reporter construct, nandrolone did not alter the rate of gene transcription. These results suggest that nandrolone may regulate MOPr expression through post-transcriptional mechanisms requiring the AR. Cito-toxicity assays demonstrated a time- and concentration dependent decrease of cells viability in SH-SY5Y cells exposed to steroids (10-6M–10-4M). This toxic effects is independent of activation of AR and sigma-2 receptor. An increased of caspase-3 activity was observed in cells treated with Nandrolone 10-6M for 48h. Collectively, these data support the existence of two cellular mechanisms that might explain the neurological syndromes observed in steroids abuser.

Androgen receptors are differentially expressed in Gleason patterns of prostate cancer and down-regulated in matched lymph node metastases

Androgen receptor (AR) expression profile in the different Gleason patterns (GP) of primary prostate cancers and nodal metastases is unknown. More information about AR distribution is needed to optimize evaluation methods and to better understand the role of AR in development and progression of prostate cancer.

Effect of electroporation-mediated diphtheria toxin A expression on PSA positive human prostate xenograft tumors in SCID mice

Current therapies to treat prostate cancer are often limited. Since it has been shown that very low concentrations of diphtheria toxin A (DT-A) result in abrogation of protein synthesis and apoptosis of cells, DT-A might serve as an efficient killer in cancer gene therapy. For this purpose we investigated in a quantitative manner using a stereological approach the apoptotic effect of DT-A in androgen receptor (AR) and prostate specific antigen (PSA) expressing cells after tumor formation in both flanks of SCID mice.

Cannabinoid receptor trafficking in peripheral cells is dynamically regulated by a binary biochemical switch

The cannabinoid G protein-coupled receptors (GPCRs) CB₁ and CB₂ are expressed in different peripheral cells. Localization of GPCRs in the cell membrane determines signaling via G protein pathways. Here we show that unlike in transfected cells, CB receptors in cell lines and primary human cells are not internalized upon agonist interaction, but move between cytoplasm and cell membranes by ligand-independent trafficking mechanisms. Even though CB receptors are expressed in many cells of peripheral origin they are not always localized in the cell membrane and in most cancer cell lines the ratios between CB₁ and CB₂ receptor gene and surface expression vary significantly. In contrast, CB receptor cell surface expression in HL60 cells is subject to significant oscillations and CB₂ receptors form oligomers and heterodimers with CB₁ receptors, showing synchronized surface expression, localization and trafficking. We show that hydrogen peroxide and other nonspecific protein tyrosine phosphatase inhibitors (TPIs) such as phenylarsine oxide trigger both CB₂ receptor internalization and externalization, depending on receptor localization. Phorbol ester-mediated internalization of CB receptors can be inhibited via this switch. In primary human immune cells hydrogen peroxide and other TPIs lead to a robust internalization of CB receptors in monocytes and an externalization in T cells. This study describes, for the first time, the dynamic nature of CB receptor trafficking in the context of a biochemical switch, which may have implications for studies on the cell-type specific effects of cannabinoids and our understanding of the regulation of CB receptor cell surface expression.

Leydig-cell tumour in children: variable clinical presentation, diagnostic features, follow-up and genetic analysis of four cases

BACKGROUND: Testicular tumours are relatively uncommon in infants and children, accounting for only 1-2% of all paediatric solid tumours. Of these approximately 1.5% are Leydig-cell tumours. Further, activating mutations of the luteinizing hormone receptor gene (LHR), as well as of the G protein genes, such as Gsalpha (gsp) and Gialpha (gip2) subunits, and cyclin-dependent kinase gene 4(CDK4) have been associated with the development of several endocrine neoplasms. AIMS/METHODS: In this report, the clinical variability of Leydig-cell tumours in four children is described. The LHR-, gsp-, gip2- and CDK4 genes were investigated to establish the possible molecular pathogenesis of the variable phenotype of the Leydig-cell tumours. RESULTS: No activating mutations in these genes were found in the four Leydig-cell tumours studied. Therefore, the absence of activating mutations in LHR, as well as in both the 'hot spot' regions for activating mutations within the G-alpha subunits and in the regulatory 'hot spot' on the CDK4 genes in these tumours indicates molecular heterogeneity among Leydig-cell tumours. CONCLUSION: Four children with a variable phenotype caused by Leydig-cell tumours are described. A molecular analysis of all the 'activating' genes and mutational regions known so far was performed, but no abnormalities were found. The lessons learnt from these clinically variable cases are: perform ultrasound early and most importantly, consider discrepancies between testicular swelling, tumour size and androgen production.

Multidrug resistance protein 4 (MRP4) expression in prostate cancer is associated with androgen signaling and decreases with tumor progression

Multidrug resistance protein 4 (MRP4) is a transmembrane transport protein found in many cell types and is involved in substrate-specific transport of endogenous and exogenous substrates. Recently, it has shown to be expressed in prostate cancer cell lines and to be among the most commonly upregulated transcripts in prostate cancer, although a comprehensive expression analysis is lacking so far. We aimed to investigate its expression by immunohistochemistry in a larger cohort of neoplastic and nonneoplastic prostate tissues (n = 441) and to correlate its expression with clinicopathological parameters including PSA-free survival times and molecular correlates of androgen signaling (androgen receptor (AR), prostate-specific antigen (PSA), and forkhead box A (FoxA)). MRP4 is widely expressed in benign and neoplastic prostate epithelia, but its expression gradually decreases during tumor progression towards castrate-resistant disease. Concordantly, it correlated with conventional prognosticators of disease progression and-within the group of androgen-dependent tumors-with AR and FoxA expression. Moreover, lower levels of MRP4 expression were associated with shorter PSA relapse-free survival times in the androgen-dependent group. In benign tissues, we found zone-dependent differences of MRP4 expression, with the highest levels in the peripheral and central zones. Although MRP4 is known to be regulated in prostate cancer, this study is the first to demonstrate a gradual downregulation of MRP4 protein during malignant tumor progression and a prognostic value of this loss of expression.

Interactions between cyclosporin A, low-density lipoprotein and the low-density lipoprotein receptor

Cyclosporine A (CSA) is a cyclic eleven amino acid, lipophilic molecule used therapeutically as an immunosuppressive agent. Cyclosporine can specifically inhibit the transcription of a number of different genes. It is known that CSA is bound almost exclusively to lipoproteins in plasma, however, the relationship between the low density lipoprotein (LDL), the LDL receptor, and CSA has not been fully elucidated. The exact mechanism of cellular uptake of CSA is unknown, but it is believed to be by simple passive diffusion across the cell membrane. In addition, it has been recently shown that the frequent finding of hypercholesterolemia seen in patients treated with CSA can be explained by a CSA-induced effect. The mechanism by which CSA induces hypercholesterolemia is not known. We have used an LDL receptor-deficient animal model, the Watanabe Heritable Hyperlipidemic (WHHL) rabbit to investigate the role of LDL and the LDL receptor in the cellular uptake of CSA. Using this animal model, we have shown that CSA uptake by lymphocytes is predominantly LDL receptor-mediated. Chemical modification of apoB-100 on LDL particles abolishes their ability to bind to the LDL receptor. When CSA is incubated with modified LDL much less is taken-up than when native LDL is incubated with CSA. Treatment of two human cell lines with CSA results in a dose-dependent decrease in LDL receptor mRNA levels. Using a novel transfection system involving the 5$\sp\prime$-flanking region of the LDL receptor gene, we have found that CSA decreases the number of transcripts, but is dependent on whether or not cholesterol is present and the stage of growth of the cells. ^

AN INVESTIGATION INTO THE MOLECULAR MECHANISMS OF ANDROGEN ACTION IN THE SERTOLI CELL

Steroid hormones regulate target cell function via quantitative and qualitative changes in RNA and protein synthesis. In the testis, androgens are known to play an important role in the regulation of spermatogenesis. The Sertoli cell (SC), whose function is thought to be supportive to the developing germ cell, has been implicated as an androgen target cell. Although cytoplasmic androgen receptors and chromatin acceptor sites for androgen-receptor complexes have been found in SC, effects on RNA synthesis have not previously been demonstrated. In this study, SC RNA synthetic activity was characterized and the effect of testosterone on SC nuclear transcriptional activity in vitro assessed. SC exhibited two fold increases in RNA and ribonucleotide pool concentrations during sexual maturation. These changes appeared to correlate with a previously observed increase in protein concentration per cell over an age span of 15-60 days. Following incubation with ('3)H-uridine, SC from older animals incorporated more label into RNA than SC from younger animals. Since the relative concentration of cytidine nucleotides was higher in SC from older rats, the age-related increase in tritium incorporation may reflect an associated increase in incorporation of ('3)H-CMP into RNA. Alternatively, the enhanced labeling may be the result of either a change in the base composition of the RNA resulting in a higher proportion of CMP and UMP in the RNA, or compartmentalization of the nucleotide pools. The physiologic consequences of these maturational alterations of nucleotide pools remains to be elucidated. RNA polymerase activities were characterized in intact nuclei obtained from cultured rat SC. (alpha)-Amanitin resistant RNA polymerase I+III activity was identical when measured in low or high ionic strength (0.05 M or 0.25 M ammonium sulfate (AS)) in the presence of MnCl(,2) or MgCl(,2), with a divalent cation optimum of 1.6 mM. RNA polymerase II was most active in 0.25 M AS and 1.6 mM MnCl(,2). The apparent Km of RNA polymerase II for UTP was 0.016 mM in 0.05 M AS and 0.037 mM in 0.25 M AS. The apparent Km values for total polymerase activity was 0.008 mM and 0.036 mM at low and high ionic strenghts, respectively. These data indicate that Sertoli cell RNA polymerase activities have catalytic properties characteristic of eukaryotic polymerase activities in general. In the presence of 21 (mu)M testosterone, RNA polymerase II activity increased two fold at 15 minutes, then declined but was still elevated over control values six hours after androgen addition. Polymerase I+III activity was not greatly affected by testosterone. The stimulation of polymerase II measured at 15 minutes was dose-dependent, with a maximum at 0.53 nM and no further stimulation up to 10('-5) M (ED(,50) = 0.25 nM testosterone), and was androgen specific. The results of preliminary RNA isolation and characterization experiments suggested that the synthesis of several species of RNA was enhanced by testosterone administration. These findings have great potential importance since they represent the first demonstration of a direct effect of androgens on the transcriptional process in the Sertoli cell. Furthermore, the results of these studies constitute further evidence that the Sertoli cell is a target for androgen action in the testis. ^