Project description:The role of androgen in breast cancer development is not fully understood although androgen receptors (AR) have been identified in breast cancer clinical samples and cell lines. However the whole spectra of androgen actions cannot be accounted to the classic AR mode of action and the possible existence of a cell surface AR has been suggested. Indeed androgens like all steroids have been reported to trigger membrane initiated signaling activity and exert specific actions. Androgens acting on the membrane can rapidly activate kinase signaling pathways and ultimately could affect gene expression. However, the molecular nature of membrane androgen binding sites represents another major persisting question. In the present study, we investigated early transcriptional effects of testosterone and the impermeable testosterone-BSA conjugate, in two breast cancer cell lines, in an attempt to decipher specific genes modified in each case, providing evidences about specific membrane initiating actions. Our data indicate that the two agents tested affect the expression of several genes. A group of genes were commonly affected while others were uniquely modified by each agent. In MDA-MB-231 cells, that are AR negative, the majority of genes affected by testosterone were also affected by testosterone-BSA indicating a membrane action. Subsequent analysis revealed that the two agents trigger different molecular pathways and cellular/molecular functions, suggestive of a molecular heterogeneity of membrane and intracellular AR. In addition, the phenotypic interactions of membrane-acting androgen with growth factor were verified at the transcriptomic level. Finally an interesting interplay between membrane-acting androgen with inflammation-related molecules, with potential clinical implications was revealed. Experiment Overall Design: Cell lines and culture conditions Experiment Overall Design: The hormone-sensitive breast cancer cell line T47D (expressing ERÎ±, ERÎ² and AR) and the hormone insensitive breast cancer cell line MDA-MB-231 (expressing only ERÎ²) were purchased from the European Collection of Cell Cultures (Salisbury, UK). T47D cells and MDA-MB-231 were cultured in RPMI-1640 medium, supplemented with 10% charcoal treated fetal bovine serum (FBS), in a humidified atmosphere of 5% CO2 in air, at 37Â°C. Culture media and serum were from Gibco BRL (Life Technologies, Paisley, UK). Experiment Overall Design: Treatment- Gene expression assay Experiment Overall Design: Cells were serum starved for 6 hours and then treated with 10-7M Testosterone or charcoal-treated Testosterone-BSA, for 3 hours. Total RNA was isolated using Nucleospin II columns (Macheray-Nagel, DÃ¼ren, Germany), labeled and hybridized according to the Affymetrix protocol (Affymetrix Gene-Chip Expression Analysis Technical Manual), using the HGU133A plus 2 chip, analyzing a total of 54675 transcripts. Signals were detected by an Affymetrix microarray chip reader.

Project description:Despite sharing much of their genomes, males and females are often highly dimorphic, reflecting at least in part the resolution of sexual conflict in response to sexually antagonistic selection. Sexual dimorphism arises owing to sex differences in gene expression, and steroid hormones are often invoked as a proximate cause of sexual dimorphism. Experimental elevation of androgens can lead to masculinization of behavior, physiology, and gene expression, but knowledge of the role of hormones remains incomplete, including how the sexes differ in their gene expression in response to exposure to hormones. We addressed these questions in a bird species with a long history of behavioral endocrinological and ecological study, the dark-eyed junco (Junco hyemalis), using a species-specific microarray. Focusing on two brain regions involved in sexually dimorphic behavior and regulation of hormone secretion, we identified 1,639 genes that differed in expression by sex in the ventromedial telencephalon and 768 in hypothalamus. In response to experimentally elevated testosterone, females exhibited a more “male-like” expression pattern than control females; unexpectedly, male expression patterns became more “female-like” rather than hyper-masculinized when compared to control males. This sex difference in pattern arose both because testosterone altered regulation of different genes in each sex and because testosterone altered regulation of the same genes differentially, i.e., up in one sex, down in the other. Hormonally regulated gene expression is a key genetic and physiological mechanism underlying sexual dimorphism, and further study should help to explain how it relates to the resolution of sexual conflict. Males and females can be highly dimorphic in metabolism and physiology despite sharing nearly identical genomes, and males and females both respond phenotypically to elevated testosterone, a steroid hormone that alters gene expression. Only recently has it become possible to learn how a hormone like testosterone affects global gene expression in non-model systems, and whether it affects the same genes in males and females. To investigate the transcriptional mechanisms by which testosterone exerts its metabolic and physiological effects on the periphery, we compared gene expression by sex and in response to experimentally elevated testosterone in a well-studied bird species, the dark-eyed junco (Junco hyemalis). We identified 324 genes in the liver, and 733 in the pectoralis muscle that were differentially expressed between males and females. In addition, we identified 1,872 genes that were differentially expressed between testosterone-treated and control individuals in at least one tissue and sex. Testosterone-treatment altered the expression of only130 genes in both males and females in the same tissue. These substantial differences in transcriptional response to testosterone suggest that males and females may employ different pathways when responding to elevated testosterone, despite the fact that many phenotypic effects of experimentally elevated testosterone are similar in the sexes. In contrast, of the 130 genes that were affected by testosterone-treatment in both sexes, 78% were regulated in the same direction (e.g. either higher or lower in testosterone-treated than control males and females). Thus, it appears that testosterone acts through both unique and shared transcriptional pathways in males and females, suggesting multiple mechanisms by which sexual conflict can be mediated.

Project description:Goal of the experiment: To examine the effects of estrogen and testosterone on gene expression in the rat mesenteric arteries. Brief description of the experiment: A dramatic difference exists in the timing of development of cardiovascular disease in men vs. women. The primary candidates underlying the cause of gender differences in cardiovascular disease are the sex steroids, estrogen and testosterone. The effect of estrogen on the cardiovascular system has been expected to be protective but this concept has become controversial. The effect of testosterone on the cardiovascular system is considered to be deleterious. In spite of these concepts there is little data on the direct effects of estrogen and testosterone on gene expression in the vasculature. Since estrogen and testosterone exert many of their effects through genomic mechanisms, the DNA microarray is an excellent tool for assessing their effects in the vasculature. In this study, ovariectomized Sprague Dawley rats were treated for 4 days with vehicle (sesame oil), estradiol benzoate (0.15 mg/kg/day), or testosterone (1 mg/kg/day). The mesenteric arteries were obtained, total RNA was extracted, and CodeLink Uniset Rat I DNA microarrays (GE) were used to identify differential gene expression. Seven genes were identified as differentially expressed from the DNA microarray data and confirmed by real time RT-PCR. The expression of D site albumin promoter binding protein and fatty acid synthase were increased in response to both estrogen and testosterone. 3alpha-hydroxysteroid dehydrogenase, interleukin 4 receptor, JunB and c-Fos expression were increased by estrogen but not by testosterone. The aryl hydrocarbon nuclear translocator-like was reduced by testosterone. These data identify genes not previously known to be responsive to estrogen and testosterone in the vasculature. Keywords: hormone treatment, vasculature, gender differences Experimental factors: hormone treatment Keywords: hormone treatment

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Testosterone acts through membrane protein GPRC6A to cause cardiac edema in zebrafish emrbyos

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