Pharmacology and clinical use of sex steroid hormone receptor modulators

T cell transgressions: Tales of T cell form and function in diverse disease states

Insights into T cell form, function, and dysfunction are rapidly evolving. T cells have remarkably varied effector functions including protecting the host from infection, activating cells of the innate immune system, releasing cytokines and chemokines, and heavily contributing to immunological memory. Under healthy conditions, T cells orchestrate a finely tuned attack on invading pathogens while minimizing damage to the host. The dark side of T cells is that they also exhibit autoreactivity and inflict harm to host cells, creating autoimmunity. The mechanisms of T cell autoreactivity are complex and dynamic. Emerging research is elucidating the mechanisms leading T cells to become autoreactive and how such responses cause or contribute to diverse disease states, both peripherally and within the central nervous system. This review provides foundational information on T cell development, differentiation, and functions. Key T cell subtypes, cytokines that create their effector roles, and sex differences are highlighted. Pathological T cell contributions to diverse peripheral and central disease states, arising from errors in reactivity, are highlighted, with a focus on multiple sclerosis, rheumatoid arthritis, osteoarthritis, neuropathic pain, and type 1 diabetes.

Distribution and Effects of Estrogen Receptors in Prostate Cancer: Associated Molecular Mechanisms

Estrogens are hormones that have been extensively presented in many types of cancer such as breast, uterus, colorectal, prostate, and others, due to dynamically integrated signaling cascades that coordinate cellular growth, differentiation, and death which can be potentially new therapeutic targets. Despite the historical use of estrogens in the pathogenesis of prostate cancer (PCa), their biological effect is not well known, nor their role in carcinogenesis or the mechanisms used to carry their therapeutic effects of neoplastic in prostate transformation. The expression and regulation of the estrogen receptors (ERs) ERα, ERβ, and GPER stimulated by agonists and antagonists, and related to prostate cancer cells are herein reviewed. Subsequently, the structures of the ERs and their splice variants, the binding of ligands to ERs, and the effect on PCa are provided. Finally, we also assessed the contribution of molecular simulation which can help us to search and predict potential estrogenic activities.

Human exposure to synthetic endocrine disrupting chemicals (S-EDCs) is generally negligible as compared to natural compounds with higher or comparable endocrine activity: how to evaluate the risk of the S-EDCs?

Theoretically, both synthetic endocrine disrupting chemicals (S-EDCs) and natural (exogenous and endogenous) endocrine disrupting chemicals (N-EDCs) can interact with endocrine receptors and disturb hormonal balance. However, compared to endogenous hormones, S-EDCs are only weak partial agonists with receptor affinities several orders of magnitude lower. Thus, to elicit observable effects, S-EDCs require considerably higher concentrations to attain sufficient receptor occupancy or to displace natural hormones and other endogenous ligands. Significant exposures to exogenous N-EDCs may result from ingestion of foods such as soy-based diets, green tea and sweet mustard. While their potencies are lower as compared to natural endogenous hormones, they usually are considerably more potent than S-EDCs. Effects of exogenous N-EDCs on the endocrine system were observed at high dietary intakes. A causal relation between their mechanism of action and these effects is established and biologically plausible. In contrast, the assumption that the much lower human exposures to S-EDCs may induce observable endocrine effects is not plausible. Hence, it is not surprising that epidemiological studies searching for an association between S-EDC exposure and health effects have failed. Regarding testing for potential endocrine effects, a scientifically justified screen should use in vitro tests to compare potencies of S-EDCs with those of reference N-EDCs. When the potency of the S-EDC is similar or smaller than that of the N-EDC, further testing in laboratory animals and regulatory consequences are not warranted.

An Inconvenient Variable: Sex Hormones and Their Impact on T Cell Responses

Epidemiologic data demonstrate sex differences in autoimmune diseases, immune responses against infection, and antitumor immunity, and accumulating evidence suggests a major role for sex hormones in mediating these differences. In this study, we review recent advances in understanding how sex hormones regulate T cell responses to alter susceptibility to autoimmunity. Although sex hormones can directly alter gene transcriptional programs of T cells, we focus in this study on how sex hormones alter T cell development and function through their effects on thymic stromal cells and innate cell types. In addition to contributing to our understanding of sex differences, these findings also have implications for the therapeutic use of sex hormones and sex hormone modulators, which are now being prescribed to increasing numbers of patients for a wide variety of indications.

The impact of sex and age on T cell immunity and ischemic stroke outcomes

Sex differences are well-recognized in ischemic stroke, a disease mainly affecting the elderly. Stroke results in robust activation of central and peripheral immune responses which contributes to functional outcome. Aging is associated with increased low-grade chronic inflammation known as "inflammaging" that renders aged males and females more susceptible to poor outcomes after ischemic stroke. Despite the fact that sex differences are well-documented in immunity and inflammation, few studies have focused on sex differences in inflammatory responses after ischemic stroke and even fewer have been performed in the context of aging. The role of T cell responses in ischemic stroke have gained increasing attention over the past decade as data suggest a major role in the pathophysiology/recovery after ischemic injury. T cells offer an attractive therapeutic target due to their relatively delayed infiltration into the ischemic brain. This review will focus on T cell immune responses in ischemic stroke, highlighting studies examining the effects of aging and biological sex.

G Protein-Coupled Estrogen Receptor: A Potential Therapeutic Target in Cancer

The G protein-coupled estrogen receptor (GPER) is a seven-transmembrane-domain receptor that mediates non-genomic estrogen related signaling. After ligand activation, GPER triggers multiple downstream pathways that exert diverse biological effects on the regulation of cell growth, migration and programmed cell death in a variety of tissues. A significant correlation between GPER and the progression of multiple cancers has likewise been reported. Therefore, a better understanding of the role GPER plays in cancer biology may lead to the identification of novel therapeutic targets, especially among estrogen-related cancers. Here, we review cell signaling and detail the functions of GPER in malignancies.

Sex Hormone Receptors in Benign and Malignant Salivary Gland Tumors: Prognostic and Predictive Role

The role of sex hormone receptors in human cancer development and progression has been well documented in numerous studies, as has the success of sex hormone antagonists in the biological therapy of many human tumors. In salivary gland tumors (SGTs), little and conflicting information about the role of the estrogen receptor alpha (ERα), progesterone receptor (PgR) and androgen receptor (AR) has been described and in most cases the use of sex hormone antagonists is not contemplated in clinical practice. In this study, we analyzed a panel of sex hormone receptors that have not been widely investigated in SGTs—ERα, PgR, AR, but also ERβ and GPR30—to define their expression pattern and their prognostic and predictive value in a case series of 69 benign and malignant SGTs. We showed the aberrant expression of AR in mucoepidermoid and oncocytic carcinoma, a strong relation between cytoplasmic ERβ expression and tumor grade, and a strong correlation between nuclear GPR30 expression and disease-free survival (DFS) of SGT patients.

GPER (GPR30): A Nongenomic Receptor (GPCR) for Steroid Hormones with Implications for Cardiovascular Disease and Cancer

Although the rapid effects of steroids, such as estrogen and aldosterone, were postulated originally to be nongenomic, it is now appreciated that activation of such signaling pathways via a steroid-acting G protein-coupled receptor, the G protein estrogen receptor (GPER), has important transcription-dependent outcomes in the regulation of cell growth and programmed cell death secondary to GPER-regulated second-messenger pathways. GPER is expressed ubiquitously and has diverse biological effects, including regulation of endocrine, immune, neuronal, and cardiovascular functions. Perhaps the most biologically important consequences of GPER activation are the regulation of cell growth, migration, and apoptotic cell death. These cell growth regulatory effects, important in cancer biology, are also relevant in the regulation of cardiac and vascular hypertrophy and in the response to ischemia. This review provides a summary of relevant findings of the impact of GPER regulation by either estradiol or aldosterone in in vitro model systems and extends those findings to in vivo studies of direct clinical relevance for development of GPER-directed agents for treatment of cancer and cardiovascular diseases associated with cellular proliferation.

Thermodynamic Meerwein-Ponndorf-Verley reduction in the diastereoselective synthesis of 17α-estradiol

The synthesis of 17α-hydroxy steroids generally requires multiple synthetic manipulations. The synthesis of 17α-estradiol is no exception, as this process involves the protection and release of the 3-hydroxy functional group. The diastereoselective reduction of the 17-keto-steroid can be utilized to prepare 17α-hydroxy-steroids. Here, 17α-estradiol was synthesized from commercially available estrone under thermodynamic Meerwein-Ponndorf-Verley (MPV) conditions in a single step, followed by simple chromatographic separation over silica gel. The remaining mixture of unreacted estrone and estradiols was easily recycled through Oppenauer oxidation to estrone, with an overall yield of 68% 17α-estradiol.

ICRAC controls the rapid androgen response in human primary prostate epithelial cells and is altered in prostate cancer

Labelled 5α-dihydrotestosterone (DHT) binding experiments have shown that expression levels of (yet unidentified) membrane androgen receptors (mAR) are elevated in prostate cancer and correlate with a negative prognosis. However, activation of these receptors which mediate a rapid androgen response can counteract several cancer hallmark functions such as unlimited proliferation, enhanced migration, adhesion and invasion and the inability to induce apoptosis. Here, we investigate the downstream signaling pathways of mAR and identify rapid DHT induced activation of store-operated Ca²⁺ entry (SOCE) in primary cultures of human prostate epithelial cells (hPEC) from non-tumorous tissue. Consequently, down-regulation of Orai1, the main molecular component of Ca²⁺ release-activated Ca²⁺ (CRAC) channels results in an almost complete loss of DHT induced SOCE. We demonstrate that this DHT induced Ca²⁺ influx via Orai1 is important for rapid androgen triggered prostate specific antigen (PSA) release. We furthermore identified alterations of the molecular components of CRAC channels in prostate cancer. Three lines of evidence indicate that prostate cancer cells down-regulate expression of the Orai1 homolog Orai3: First, Orai3 mRNA expression levels are significantly reduced in tumorous tissue when compared to non-tumorous tissue from prostate cancer patients. Second, mRNA expression levels of Orai3 are decreased in prostate cancer cell lines LNCaP and DU145 when compared to hPEC from healthy tissue. Third, the pharmacological profile of CRAC channels in prostate cancer cell lines and hPEC differ and siRNA based knock-down experiments indicate changed Orai3 levels are underlying the altered pharmacological profile. The cancer-specific composition and pharmacology of CRAC channels identifies CRAC channels as putative targets in prostate cancer therapy.

Vascular effects of aldosterone: sorting out the receptors and the ligands

Aldosterone has actions far beyond its role as a renal regulator of sodium reabsorption, and broader mechanisms of action than simply a transcriptional regulator. Aldosterone has a number of vascular effects, including regulation of vascular reactivity and vascular growth and/or development. Aldosterone-mediated effects on vascular reactivity reflect a balance between its endothelial-dependent vasodilator effects and its direct smooth muscle vasoconstrictor effects. The endothelial vasodilator effects of aldosterone are mediated by phosphatidylinositol 3-kinase-dependent activation of nitric oxide synthase. G-Protein oestrogen receptor (GPER) is a recently recognized G-protein coupled receptor (GPCR) that is activated by steroid hormones. It was first recognized as the GPCR mediating the rapid effects of oestrogens. Activation of GPER also mediates at least some of the vascular effects of aldosterone in smooth muscle and endothelial cells. In vascular endothelial cells, aldosterone activation of GPER mediates vasodilation. In contrast, activation of endothelial mineralocorticoid receptors has been linked to enhanced vasoconstrictor and/or impaired vasodilator responses.

Potency matters: thresholds govern endocrine activity

Whether thresholds exist for endocrine active substances and for endocrine disrupting effects of exogenous chemicals has been posed as a question for regulatory policy by the European Union. This question arises from a concern that the endocrine system is too complex to allow estimations of safe levels of exposure to any chemical with potential endocrine activity, and a belief that any such chemical can augment, retard, or disrupt the normal background activity of endogenous hormones. However, vital signaling functions of the endocrine system require it to continuously discriminate the biological information conveyed by potent endogenous hormones from a more concentrated background of structurally similar, endogenous molecules with low hormonal potential. This obligatory ability to discriminate important hormonal signals from background noise can be used to define thresholds for induction of hormonal effects, without which normal physiological functions would be impossible. From such thresholds, safe levels of exposure can be estimated. This brief review highlights how the fundamental principles governing hormonal effects - affinity, efficacy, potency, and mass action - dictate the existence of thresholds and why these principles also define the potential that exogenous chemicals might have to interfere with normal endocrine functioning.

Synthesis of substituted estradiols by the selective aromatization of A-ring of steroidal 19-nor-Δ-4-3-ketones with phenylselenyl halides/hydrogen peroxide

A range of 6-, 7-, and 11-substituted estradiols were synthesized by the selective aromatization of the A-ring of 19-nor steroids using phenylselenyl halides followed by oxidation with hydrogen peroxide. Established methods utilizing copper(II) halides failed or have given poor yields with these substrates.