Lessons from KEEPS: the Kronos Early Estrogen Prevention Study

The Kronos Early Estrogen Prevention Study (KEEPS) was a randomized, double-blind, placebo-controlled trial designed to determine the effects of hormone treatments (menopausal hormone treatments [MHTs]) on the progression of carotid intima-medial thickness (CIMT) in recently menopausal women. Participants less than 3 years from menopause and without a history of overt cardiovascular disease (CVD), defined as no clinical CVD events and coronary artery calcium < 50 Agatston units, received either oral conjugated equine estrogens (0.45 mg/day) or transdermal 17β-estradiol (50 µg/day), both with progesterone (200 mg/day for 12 days/month), or placebo pills and patches for 4 years. Although MHT did not decrease the age-related increase in CIMT, KEEPS provided other important insights about MHT effects. Both MHTs versus placebo reduced the severity of menopausal symptoms and maintained bone density, but differed in efficacy regarding mood/anxiety, sleep, sexual function, and deposition of β-amyloid in the brain. Additionally, genetic variants in enzymes for metabolism and uptake of estrogen affected the efficacy of MHT for some aspects of symptom relief. KEEPS provides important information for use of MHT in clinical practice, including type, dose, and mode of delivery of MHT recently after menopause, and how genetic variants in hormone metabolism may affect MHT efficacy on specific outcomes.

The Kronos Early Estrogen Prevention Study (KEEPS): what have we learned?

OBJECTIVE

The Kronos Early Estrogen Prevention Study (KEEPS) was designed to address gaps in understanding the effects of timely menopausal hormone treatments (HT) on cardiovascular health and other effects of menopause after the premature termination of the Women's Health Initiative.

METHOD

The KEEPS was a randomized, double-blinded, placebo-controlled trial to test the hypothesis that initiation of HT (oral conjugated equine estrogens [o-CEE] or transdermal 17β-estradiol [t-E2]) in healthy, recently postmenopausal women (n = 727) would slow the progression of atherosclerosis as measured by changes in carotid artery intima-media thickness (CIMT).

RESULTS

After 4 years, neither HT affected the rate of increase in CIMT. There was a trend for reduced accumulation of coronary artery calcium with o-CEE. There were no severe adverse effects, including venous thrombosis. Several ancillary studies demonstrated a positive effect on mood with o-CEE, and reduced hot flashes, improved sleep, and maintenance of bone mineral density with both treatments. Sexual function improved with t-E2. There were no significant effects of either treatment on cognition, breast pain, or skin wrinkling. Variants of genes associated with estrogen metabolism influenced the age of menopause and variability in effects of the HT on CIMT. Platelet activation associated with the development of white matter hyperintensities in the brain.

CONCLUSIONS

KEEPS and its ancillary studies have supported the value and safety of the use of HT in recently postmenopausal women and provide a perspective for future research to optimize HT and health of postmenopausal women. The KEEPS continuation study continues to pursue these issues.

Aromatase: Contributions to Physiology and Disease in Women and Men

Aromatase (estrogen synthetase; EC 1.14.14.1) catalyzes the demethylation of androgens' carbon 19, producing phenolic 18-carbon estrogens. Aromatase is most widely known for its roles in reproduction and reproductive system diseases, and as a target for inhibitor therapy in estrogen-sensitive diseases including cancer, endometriosis, and leiomyoma (141, 143). However, all tissues contain estrogen receptor-expressing cells, the majority of genes have a complete or partial estrogen response element that regulates their expression (61), and there are plentiful nonreceptor effects of estrogens (79); therefore, the effect of aromatase through the provision of estrogen is almost universal in terms of health and disease. This review will provide a brief but comprehensive overview of the enzyme, its role in steroidogenesis, the problems that arise with its functional mutations and mishaps, the roles in human physiology of aromatase and its product estrogens, its current clinical roles, and the effects of aromatase inhibitors. While much of the story is that of the consequences of the formation of its product estrogens, we also will address alternative enzymatic roles of aromatase as a demethylase or nonenzymatic actions of this versatile molecule. Although this short review is meant to be thorough, it is by no means exhaustive; rather, it is meant to reflect the cutting-edge, exciting properties and possibilities of this ancient enzyme and its products.

Bioinformatic analysis of benzo-α-pyrene-induced damage to the human placental insulin-like growth factor-1 gene

INTRODUCTION

Intrauterine growth restriction (IUGR) has been associated with exposure to polyaromatic hydrocarbons (PAHs) which are released in the combustion of oil, fuel, gas, garbage, and tobacco. Pregnant women exposed to PAHs are at risk of the effects of these environmental toxins; for example, benzo-α-pyrene (BαP) is able to enter the blood stream and could contribute to IUGR or other developmental abnormalities via effects on the placental cells. Since IUGR has been associated with decreased cord blood concentrations of immunoreactive insulin-like growth factor 1 (ir-IGF-1) and IUGR has been associated with disordered development and fetal programming, we tested the effects of BαP on human placental trophoblast cells in culture.

EXPERIMENTAL

IGF-1 expression and activation was studied using an immortalized human placental trophoblast cell line (HTR-8). The cells were treated with vehicle control or 1 µmol/L BαP, or 5 µmol/L BαP for 12 hours. RNA was extracted and the exons of IGF-1 were amplified using reverse transcriptase-polymerase chain reaction (RT-PCR). The ir-IGF-1 expression levels were compared using gel electrophoresis. The PCR products were sequenced, and levels of mutation were measured with comparative sequence analysis. A computational protein analysis (computer simulation) was performed in order to assess the potential impact of BαP-associated mutation on IGF-1 protein function.

RESULTS

The IGF-1 expression decreased considerably in BαP-treated cells relative to untreated controls (P < .05), also in a dose-dependent manner. Comparative sequence analysis indicated that the level of BαP exposure correlated with the percentage of base pair mutations in IGF-1 nucleotide sequences for both treatment groups (P < .05). Shifts were observed in the open reading frame, indicating a possible change in the IGF-1 start codon. Protein folding simulation analysis indicated that the base pair changes induced by BαP weakened IGF-1-IGF binding protein (IGFBP) interaction.

CONCLUSIONS

In concordance with the previous findings, exposure of human placental trophoblast cells to BαP exposure results in reduction of IGF-1 expression and base pair mutations. The direct action of BαP on the placenta indicates that it may not be necessary for BαP to access other maternal tissues in order for gene abnormalities to occur. Given that PAHs are known to work through aryl hydrocarbon hydrolase (AHH), these results are likely due to the presence of AHH in HTR cells. Computational modeling of BαP actions on IGF1, substrate-ligand binding, supports the biological premise of this work and underlines the need to determine actual biological effects rather than equating immune to bioactivity of IGF1.

Self-reported menopausal symptoms, coronary artery calcification, and carotid intima-media thickness in recently menopausal women screened for the Kronos early estrogen prevention study (KEEPS)

OBJECTIVE

To determine whether self-reported menopausal symptoms are associated with measures of subclinical atherosclerosis.

DESIGN

Cross-sectional analysis.

SETTING

Multicenter, randomized controlled trial.

PATIENT(S)

Recently menopausal women (n = 868) screened for the Kronos Early Estrogen Prevention Study (KEEPS).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Baseline menopausal symptoms (hot flashes, dyspareunia, vaginal dryness, night sweats, palpitations, mood swings, depression, insomnia, irritability), serum E2 levels, and measures of atherosclerosis were assessed. Atherosclerosis was quantified using coronary artery calcium (CAC) Agatston scores (n = 771) and carotid intima-media thickness (CIMT). Logistic regression model of menopausal symptoms and E2 was used to predict CAC. Linear regression model of menopausal symptoms and E2 was used to predict CIMT. Correlation between length of time in menopause with menopausal symptoms, E2, CAC, and CIMT were assessed.

RESULT(S)

In early menopausal women screened for KEEPS, neither E2 nor climacteric symptoms predicted the extent of subclinical atherosclerosis. Palpitations and depression approached significance as predictors of CAC. Other symptoms of insomnia, irritability, dyspareunia, hot flashes, mood swings, night sweats, and vaginal dryness were not associated with CAC. Women with significantly elevated CAC scores were excluded from further participation in KEEPS; in women meeting inclusion criteria, neither baseline menopausal symptoms nor E2 predicted CIMT. Years since menopause onset correlated with CIMT, dyspareunia, vaginal dryness, and E2.

CONCLUSION(S)

Self-reported symptoms in recently menopausal women are not strong predictors of subclinical atherosclerosis. Continued follow-up of this population will be performed to determine whether baseline or persistent symptoms in the early menopause are associated with progression of cardiovascular disease.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00154180.

The PBRN initiative: transforming new technologies to improve patient care

The NIDCR-supported Practice-based Research Network initiative presents dentistry with an unprecedented opportunity by providing a pathway for modifying and advancing the profession. It encourages practitioner participation in the transfer of science into practice for the improvement of patient care. PBRNs vary in infrastructure and design, and sustaining themselves in the long term may involve clinical trial validation by regulatory agencies. This paper discusses the PBRN concept in general and uses the New York University College of Dentistry's Practitioners Engaged in Applied Research and Learning (PEARL) Network as a model to improve patient outcomes. The PEARL Network is structured to ensure generalizability of results, data integrity, and to provide an infrastructure in which scientists can address clinical practitioner research interests. PEARL evaluates new technologies, conducts comparative effectiveness research, participates in multidisciplinary clinical studies, helps evaluate alternative models of healthcare, educates and trains future clinical faculty for academic positions, expands continuing education to include "benchmarking" as a form of continuous feedback to practitioners, adds value to dental schools' educational programs, and collaborates with the oral health care and pharmaceutical industries and medical PBRNs to advance the dental profession and further the integration of dental research and practice into contemporary healthcare (NCT00867997, NCT01268605).

Using basic science to design a clinical trial: baseline characteristics of women enrolled in the Kronos Early Estrogen Prevention Study (KEEPS)

Observational and epidemiological studies suggest that menopausal hormone therapy (MHT) reduces cardiovascular disease (CVD) risk. However, results from prospective trials showed neutral or adverse effects most likely due to differences in participant demographics, such as age, timing of initiation of treatment, and preexisting cardiovascular disease, which reflected in part the lack of basic science information on mechanisms of action of hormones on the vasculature at the time clinical trials were designed. The Kronos Early Estrogen Replacement Study (KEEPS) is a prospective, randomized, controlled trial designed, using findings from basic science studies, to test the hypothesis that MHT when initiated early in menopause reduces progression of atherosclerosis. KEEPS participants are younger, healthier, and within 3 years of menopause thus matching more closely demographics of women in prior observational and epidemiological studies than women in the Women's Health Initiative hormone trials. KEEPS will provide information relevant to the critical timing hypothesis for MHT use in reducing risk for CVD.

Ezrin is a key element in the human vagina

OBJECTIVE

The vagina is a complex tubular structure that has reproductive, support and barrier functions. These depend on the cytoarchitecture of the vaginal cells, which is controlled by key proteins. Cytoskeletal proteins determine cell polarity and membrane specializations by integrating the actin cytoskeleton with cell membranes. This integration is the domain of cytoskeletal proteins including the MERM protein family (moesin-ezrin-radixin-Merlin). Nothing is known about the cyto-localization of the MERM's in the vaginal epithelium or how it influences the cytoarchitecture of the vaginal epithelium and stroma.

DESIGN

Full-thickness human vaginal fornix samples were obtained from 20 normal human specimens obtained at surgery for pelvic relaxation. Light- and electron microscopical immunohistochemistry (IHC) were used to identify and study activation and cellular localization of immuno-reactive-ezrin (ir-ezrin), a prototypical MERM.

RESULTS

Ir-ezrin was identified in the stratified squamous vaginal epithelium and connective tissue (fibroblasts, blood vessels and leucocytes). "H" scoring indicated that ir-ezrin staining is denser in the vaginal epithelium than in other layers, that the ir-ezrin staining was associated with increased keratinization and with the size of the tight junctions (p<0.01). Both the amounts and localization of ir-ezrin were associated with high levels of estrogen, identified by the menstrual history and keratinization of the superficial vaginal epithelium. The density of stromal ir-ezrin was increased in the presence of dense epithelial keratinization. Immuno-reactive-ezrin staining was most pronounced near the cell membranes of both keratinized and non-keratinized epithelium, indicating that ezrin activation (unfolding and movement to the membrane) had occurred. Ultra-structural examination of the epithelium showed intra-cellular ir-ezrin to be localized to junctional complexes that have been associated with decreased mucosal penetration by microorganisms. Ir-ezrin was widely distributed throughout stromal fibro-muscular cell, vessels and immunocytes.

CONCLUSIONS

MERM's, represented by ezrin, are widely present in the vaginal wall. This has implications for the strength and resilience of this tubular structure and may be the case in other internal genital tissues. Ezrin's localization and association with cell specializations indicate that in the vagina, as in other tissues, ezrin likely modulates vaginal cell-cell interactions including the changing vaginal cellular interface with the external environment, the regulation of the elasticity of the vagina, and the regulation of microbial and chemical traffic that determine the pH and microbial environment of the vagina. In other work we have shown that ezrin expression is induced by estradiol. The increase of ir-ezrin staining during the appearance of keratinization and maturation of the vaginal cytology indicates that estrogen may regulate vaginal ezrin and thereby the properties of the vaginal wall and epithelium.

Circulation DNA: biological implications for cancer metastasis and immunology

Circulation cell free DNA (cf-DNA) is of considerable interest to oncology researchers seeking to isolate specific cancer markers. Here, we focus on the origin and biological implications of cf-DNA, exploring its potential roles in cancer biology and medicine. We hypothesize that cf-DNA is primarily released by living cancer cells in addition to apoptotic or necrotic cancer cells for three reasons: (1) following radiotherapy, cf-DNA quantities are significantly reduced in a high percentage of patients although radiation-induced massive apoptosis is expected; (2) cancer cell DNA concentration in cultured supernatants increases with cell proliferation when few apoptotic or necrotic cells are present; and (3) DNA concentration increases in normal lymphocyte cultures following stimulation with phytohemagglutinin, lipopolysaccharide or antigen. Our hypotheses have major biological implications in cancer biology. First, cancer cf-DNA may transform normal cells and form adjacent or remote metastases or second primary cancer. In this context, we also have raised an alarming advice that the cancer may be potentially infectious. Secondly, if a normal cf-DNA contains cytokine sequence, it may behave like an intrinsic DNA vaccine, producing therapeutic cytokine. If normal cf-DNA contains a sequence of a non-mutated oncogene or tumor suppressor gene, homologous recombination with the cancer genome may occur leading to knock out mutated oncogene or tumor suppressor gene that could thus elicit a spontaneous remission of cancer.

KEEPS: The Kronos Early Estrogen Prevention Study

Observational studies have indicated that hormone therapy given at or after menopause is linked to substantial reduction in cardiovascular disease and its risk factors. Recent findings from the Women's Health Initiative (WHI) clinical trial, however, indicate that combined estrogen plus progestin hormone therapy, as well as estrogen-alone hormone therapy (given to women without a uterus), is ineffective in preventing the new onset of cardiac events in previously healthy late menopausal women. Further, the secondary prevention trial, the Heart and Estrogen/progestin Replacement Study (HERS), also failed to demonstrate any benefit of initiation of hormone therapy in women with established coronary heart disease. In light of these results, a hypothesis has arisen that early initiation of hormone therapy, in women who are at the inception of their menopause, will delay the onset of subclinical cardiovascular disease in women. The rationale that earlier intervention than that performed in the WHI and HERS trials will provide cardiovascular benefit to women is the driving force behind the Kronos Early Estrogen Prevention Study, or KEEPS. KEEPS is a multicenter, 5-year clinical trial that will evaluate the effectiveness of 0.45 mg of conjugated equine estrogens, 50 microg weekly transdermal estradiol (both in combination with cyclic oral, micronized progesterone, 200 mg for 12 days each month), and placebo in preventing progression of carotid intimal medial thickness and the accrual of coronary calcium in women aged 42-58 years who are within 36 months of their final menstrual period. A total of 720 women are planned to be enrolled in 2005, with an anticipated close-out of the trial in 2010. This overview summarizes the recruitment and methodology of the KEEPS trial.

Protein misfolding and misprocessing in complex disease

Scientists from over 20 major research centers recently convened to discuss advances and new discoveries in "Protein MisFolding and MisProcessing in Disease." Understanding protein mechanisms the underlying etiology of complex diseases lies in analyzing the associated biochemical mechanisms, which include folding patterns, processing patterns, chaperone regulators, stress pathways, and signal transduction.

The influence of environmental adaptation on bacterial genome structure

AIMS

Researchers have long been puzzled by the diversity of life. Now that the complete genomic sequence of many organisms has been determined, it is possible to evaluate the impact of organismal variation on sequence structure or vice versa. The aim of this investigation was to explore genomic changes mandated by organismal adaptation to its ecological niches.

METHODS AND RESULTS

Coding sequences from three phylogenetically related bacterial species namely Mycoplasma genitalium, M. pneumoniae and Ureaplasma urealyticum were subject to in depth sequence analyses. M. genitalium and M. pneumoniae both belong to the genus Mycoplasma while U. urealyticum is a member of the genus Ureaplasma. However, M. genitalium and U. urealyticum are urogenital pathogens while M. pneumoniae is a respiratory pathogen. Complete transcriptomes were downloaded from NCBI for each species, and were subject to in silico investigation using in-house software, and public sequence analysis tools. Clear similarities in transcriptome structure were identified among the functionally similar species M. genitalium and U. urealyticum while no such relationship was identified among the phylogenetically related species M. genitalium and M. pneumoniae.

CONCLUSIONS

It is plausible to conclude that, in these bacterial species, environmental stimuli might be more influential in shaping sequence signatures than phylogenetic relationships.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study suggests that molecular signatures within the transcriptomes of the species examined are likely to be a product of evolutionary adaptation to diverse environmental ecological stimuli, and not a result of common phylogeny.

Diagnostic microarray: an array of possibilities for parasitology

Parasites affect a majority of the world's population. Despite this fact, dreams of developing vaccines remain far off. Scientists have long studied gene expression as a hallmark of gene activities reflecting current cell conditions. Analyzing differentially expressed genes is a major initiative, and most labs recoil at the amount of time and high costs required obtaining results. By employing microarrays, researchers can decrease their reliance upon time consuming techniques; consequently, microarray is beginning to dominate other molecular diagnostic technologies. Moreover, the ability of microarrays to monitor simultaneous gene expression of thousands of genes and to produce broad arrays of data has the potential to shift the resources of the scientists from data gathering to analyzing data that are already available. As microarray technology improves and its cost decreases, the role of ability to "see" the molecular biology pathways involved in parasite host relationships will place this technology at the forefront of parasite research.

Estradiol affects axo-somatic contacts of neuroendocrine cells in the arcuate nucleus of adult rats

It has been shown that gonadal steroids have the capacity to induce synaptic plasticity in certain areas of the nervous system. Previously we have demonstrated that due to the effect of estradiol there is a transient decrease in the number of GABAergic axo-somatic synapses in the arcuate nucleus. By using systemic application of the tracer Fluorogold we retrogradely labeled a subpopulation of arcuate neurons that project to the median eminence. We than applied the disector method for synapse quantification and found that these "hypophysiotropic neurons" receive less axo-somatic inputs. We found that 17beta-estradiol induced a decrease in the numerical density of axo-somatic contacts of these retrogradely-labeled neoroendocrine cells. Our data support the hypothesis that the hormonally driven morphological synaptic plasticity is neuron specific within the arcuate nucleus and plays a decisive role in the regulation of anterior pituitary.

New approaches to the understanding of tamoxifen action and resistance

Tamoxifen (TAM) provides an effective agent for treatment of hormone-dependent breast cancer but resistance uniformly ensues upon continued use. Additional studies are required to define more precisely the mechanisms involved in development of resistance. We conducted systematic experimental and clinical studies based on the hypothesis that tumors exposed to TAM long-term may develop resistance by becoming hypersensitive to its estrogenic effects. These investigations uncovered new features of the TAM resistance (TR) phenomenon and identified possible means for its prevention and/or elimination. Initially we confirmed that TR may be divided into two subtypes, primary and acquired resistance, and that these differ by certain important characteristics including the level of the possible involvement of adaptive and genetic components. Then we distinguished at least three consequent stages of this phenomenon: stage I when TAM behaves as an antiestrogen, stage II with development of increased sensitivity to the agonistic (pro-estrogenic) properties of TAM and stage III with an adaptive increase in sensitivity to estradiol (E(2)). During this evolutionary process, as shown in vitro, MAP kinase (MAPK) and aromatase activities increase. The time frame of the increase in MAPK activity as a rule outpaces the increase in aromatase activity during the course of the development of TR. This may occur as a response to estrogen deprivation or interruption of the process of estrogen signaling and can be one of the promoting factors of increased aromatase activation. On the other hand, the chronology of these events indicates that changes in the MAPK cascade can be more important for the early steps of the development and maintenance of the TR state. Changes in local estrogen production/sensitivity to E(2) are perhaps essential for the later steps of this phenomenon. We have explored the use of a growth factor-blocking agent to abrogate the adaptive changes in sensitivity. Farnesylthiosalicylic acid (FTS), an inhibitor of GTP-Ras binding to its membrane acceptor site, reduces the increase in the number of MCF-7 cells induced by long-term TAM treatment. It also decreases MAPK activity in TAM-treated MCF-7 cells and in established TR cell lines. Alone or in combination with letrozole (presumably, through the influence on MAPK pathway) FTS exerts moderate inhibitory effects on aromatase activity in estrogen-deprived or estrogen-exposed MCF-7 cells. Taken together, our observations suggest that FTS is a 'candidate drug' for the treatment of TR. Both the adaptive and genetic types of resistance may be amenable to this approach. Our studies underline the possible importance of starting the treatment/prevention of TR early on. From our clinical studies using immunohistochemistry, there is a rather strong rationale to include as a predisposing factor in the development of TR the increase in MAPK and aromatase activities in human primary breast tumors. In summary, data obtained during the course of this project may be considered as evidence supporting the principle that processes resulting in responses to TAM as an agonist and the development of estrogen hypersensitivity of breast cancer cells could potentially be mechanistically linked.

Estrogen, synaptic plasticity and hypothalamic reproductive aging

Unlike primates who undergo ovarian failure and loss of sex steroids at the end of reproduction, aging rodents undergo constant vaginal estrus followed by constant diestrus and finally anestrus, which indicates the absence of responsive ovarian follicles. The latter state is analogous to menopause in women. The timing of the appearance of constant estrus is determined by many factors including estrogen exposure in the brain during development and the number of times that the animal gets pregnant. The chief site of this reproductive aging in rat brains is the arcuate nucleus of the hypothalamus. The transition from normal cycles to constant estrus parallels the females' gradually decreased ability to respond to administered estradiol with a cycle of inhibition followed by disinhibition of gonadotrophin-releasing hormone. Evidence has accumulated indicating this to be due to a loss of the rat's ability to respond to markedly elevated estradiol with the usual arcuate nucleus neuro-glial plasticity that supports the estrogen-induced gonadotrophin surge (EIGS). Just as male rats are not capable of an EIGS, aged females loose this ability through repeated EIGS. Experiments indicate that in male rats the hypothalamic synaptology that develops as a result of exposure to testicular androgens in the perinatal period (brain sexual differentiation) is a result of conversion of testosterone from the testes to estrogen in the brain and is therefore due to early estrogen exposure. Aging females appear to reach a synaptology similar to males and constant estrus as a result of repeated exposure to ovarian estrogens during their reproductive careers. The relative role of aging and hormonal factors remains unclear. Morphological evidence is presented that indicates the above effects of estrogen involve changes in hypothalamic arcuate nucleus neurons and glia, including changes in the organization of perikaryal membranes as well as arcuate nucleus synaptology and the load of peroxidase in the astroglia. A possible role for free radicals (reactive oxygen species) in hypothalamic reproductive aging has been proposed. Such a mechanism is supported by evidence that the anti-oxidant vitamin E delays the onset of constant estrus and the accumulation of glial peroxidase in aging female rats. However, since the synaptology and peroxidase load in constant estrus females is independent of the age at which the constant estrus occurs, it appears that the role of (repeated) estradiol exposure is more deterministic of hypothalamic failure than is aging, per se.

Ovarian epithelial carcinoma tyrosine phosphorylation, cell proliferation, and ezrin translocation are stimulated by interleukin 1alpha and epidermal growth factor

BACKGROUND

Ezrin is a member of the ezrin, radixin, and moesin family. These proteins are membrane-actin cross-linking proteins. Furthermore, ezrin is an important signal transduction protein that undergoes phosphorylation and translocation on stimulation by growth factors. Ezrin phosphorylation and translocation are thought to be correlated with cell motility, invasion, and carcinoma metastasis. Recently, the authors reported that an ezrin antisense phosphorothionate could significantly inhibit endometrial carcinoma cells' penetration in the Matrigel membrane cancer invasion assay. In the current study, the authors measured ezrin content in clinical ovarian epithelial carcinoma (OVCA) specimens and cell lines and investigated whether interleukin (IL)-1alpha and epidermal growth factor (EGF) induce an invasive phenotype in OVCA cells via ezrin phosphorylation and translocation.

METHODS

Twenty-five normal ovary, 25 primary OVCA, 21 metastatic OVCA tissue (7 in omentum, 16 in ascites), and 3 OVCA cell lines were collected for Western blot detection of ezrin content. The OVCA cell line SKOV3 was treated with IL-1alpha or EGF. Indirect immunofluorescence staining followed by confocal laser scanning and double-staining electron microscopic immunohistochemistry were used to investigate changes in the intracellular distribution of ezrin and cell morphology after IL-1alpha or EGF treatment. The content of ezrin was measured by Western blotting and analyzed by the National Institutes of Health Image computer program. Immunoprecipitation and Western blot techniques were used for ezrin phosphorylation studies. Genistein was used to block tyrosine phosphorylation.

RESULTS

(1) Ezrin was overexpressed in OVCA, with the highest values in metastases. (2) Interleukin-1alpha and EGF significantly increased OVCA tyrosine phosphorylation, ezrin translocation, and cell growth. (3) These effects were abolished by treatment with the tyrosine kinase inhibitor, genistein. (4) Treatment with IL-1alpha or EGF induced an invasive phenotype, i.e., membrane ruffling, and process formation.

CONCLUSIONS

High expression and activation of ezrin appear to be related to OVCA metastatic behavior. Interleukin-1alpha and EGF may regulate OVCA invasive behavior by activating ezrin tyrosine phosphorylation, translocation, and cancer cell proliferation. The authors' results may partially explain why OVCA patients with positive macrophage colony stimulating factor (a chemoattractant of IL-1alpha secreting monocytes) or EGF receptors (c-erb B-2) have a poor prognosis.

Ovarian epithelial carcinoma tyrosine phosphorylation, cell proliferation, and ezrin translocation are stimulated by interleukin 1alpha and epidermal growth factor

BACKGROUND

Ezrin is a member of the ezrin, radixin, and moesin family. These proteins are membrane-actin cross-linking proteins. Furthermore, ezrin is an important signal transduction protein that undergoes phosphorylation and translocation on stimulation by growth factors. Ezrin phosphorylation and translocation are thought to be correlated with cell motility, invasion, and carcinoma metastasis. Recently, the authors reported that an ezrin antisense phosphorothionate could significantly inhibit endometrial carcinoma cells' penetration in the Matrigel membrane cancer invasion assay. In the current study, the authors measured ezrin content in clinical ovarian epithelial carcinoma (OVCA) specimens and cell lines and investigated whether interleukin (IL)-1alpha and epidermal growth factor (EGF) induce an invasive phenotype in OVCA cells via ezrin phosphorylation and translocation.

METHODS

Twenty-five normal ovary, 25 primary OVCA, 21 metastatic OVCA tissue (7 in omentum, 16 in ascites), and 3 OVCA cell lines were collected for Western blot detection of ezrin content. The OVCA cell line SKOV3 was treated with IL-1alpha or EGF. Indirect immunofluorescence staining followed by confocal laser scanning and double-staining electron microscopic immunohistochemistry were used to investigate changes in the intracellular distribution of ezrin and cell morphology after IL-1alpha or EGF treatment. The content of ezrin was measured by Western blotting and analyzed by the National Institutes of Health Image computer program. Immunoprecipitation and Western blot techniques were used for ezrin phosphorylation studies. Genistein was used to block tyrosine phosphorylation.

RESULTS

(1) Ezrin was overexpressed in OVCA, with the highest values in metastases. (2) Interleukin-1alpha and EGF significantly increased OVCA tyrosine phosphorylation, ezrin translocation, and cell growth. (3) These effects were abolished by treatment with the tyrosine kinase inhibitor, genistein. (4) Treatment with IL-1alpha or EGF induced an invasive phenotype, i.e., membrane ruffling, and process formation.

CONCLUSIONS

High expression and activation of ezrin appear to be related to OVCA metastatic behavior. Interleukin-1alpha and EGF may regulate OVCA invasive behavior by activating ezrin tyrosine phosphorylation, translocation, and cancer cell proliferation. The authors' results may partially explain why OVCA patients with positive macrophage colony stimulating factor (a chemoattractant of IL-1alpha secreting monocytes) or EGF receptors (c-erb B-2) have a poor prognosis.

17alpha-methyl testosterone is a competitive inhibitor of aromatase activity in Jar choriocarcinoma cells and macrophage-like THP-1 cells in culture

17alpha-methyl testosterone is a synthetic androgen with affinity for the androgen receptor. 17alpha-methyl testosterone is used widely as a component of hormone replacement therapy. Previous reports have indicated that contrary to testosterone, 17alpha-methyl testosterone is not aromatized. However, 17alpha-methyl testosterone still could affect local estrogen formation by regulating aromatase expression or by inhibiting aromatase action. Both possibilities have important clinical implications. To evaluate the effect of 17alpha-methyl testosterone on the expression and activity of aromatase, we tested the choriocarcinoma Jar cell line, a cell line that express high levels of P450 aromatase, and the macrophage-like THP-1 cells, which express aromatase only after undergoing differentiation. We found that in both cell lines, 17alpha-methyl testosterone inhibits aromatase activity in a dose-related manner. The curve of inhibition parallels that of letrozole and gives complete inhibition at 10(-4) M 17alpha-methyl testosterone, determined by the tritium release assay. 17alpha-methyl testosterone does not have detectable effects on aromatase RNA and protein expression by Jar cells. Undifferentiated THP-1 cells had no aromatase activity and showed no effect of 17alpha-methyl testosterone, but differentiated THP-1 (macrophage-like) cells had a similar inhibition of aromatase activity by 17alpha-methyl testosterone to that seen in Jar cells. The Lineweaver-Burke plot shows 17alpha-methyl testosterone to be a competitive aromatase inhibitor. Our results show for the first time that 17alpha-methyl testosterone acts as an aromatase inhibitor. These findings are relevant for understanding the effects of 17alpha-methyl testosterone as a component of hormone replacement therapy. 17alpha-methyl testosterone may, as a functional androgen and orally active steroidal inhibitor of endogenous estrogen production, also offer special possibilities for the prevention/treatment of hormone-sensitive cancers.

Effect of long-term estrogen deprivation on apoptotic responses of breast cancer cells to 17beta-estradiol

BACKGROUND

High doses of estrogen can promote tumor regression in postmenopausal women with hormone-dependent breast cancer, but the mechanism is unknown. We investigated the molecular basis of this process by using LTED cells, which were derived by growing MCF-7 breast cancer cells under long-term (6-24 months) estrogen-deprived conditions.

METHODS

We treated LTED and MCF-7 cells with various concentrations of 17beta-estradiol (estradiol) and assayed their growth by counting the cells and measured apoptosis by annexin V staining and DNA fragmentation. Using western blot analysis, we also examined the expression of the apoptosis-inducing system of the Fas death receptor protein and its ligand, FasL, in these cells. To assess the involvement of Fas and FasL in the induction of apoptosis in LTED cells, we used activating anti-Fas antibodies and the universal caspase inhibitor Z-VAD. Finally, we examined the expression of Fas protein in E8CASS and BSK3 cells, two other cell lines derived by depriving MCF-7 cells of estrogen long term, and the responses of these cells to high-dose estradiol. All statistical tests were two-sided.

RESULTS

High concentrations of estradiol (>or=0.1 nM) resulted in a statistically significant, 60% reduction in the growth of LTED cells (P< .001) and in a sevenfold increase in apoptosis (P< .001) as compared with levels in vehicle-treated cells. Both LTED and MCF-7 cells expressed FasL, but only LTED cells expressed Fas. Treatment of LTED cells with 0.1 nM estradiol increased the expression of FasL. Activating anti-Fas antibodies increased apoptosis of LTED cells, which was further stimulated by estradiol. Z-VAD blocked estradiol-induced apoptosis. E8CASS cells, which express Fas protein, but not BSK3 cells, which do not, also responded to 0.1 nM estradiol by increasing apoptosis.

CONCLUSION

Tumor regression induced by high-dose estrogen therapy in postmenopausal woman may result from estrogen activation of Fas-mediated apoptosis.

Estrogen synthetase (aromatase) immunohistochemistry reveals concordance between avian and rodent limbic systems and hypothalami

During amniote evolution, an early divergence occurred about 300 million years ago between the reptilian lines leading to the appearance of birds (anapsids) and mammals (synapsids). The different functional requirements of these vertebrate groups have involved divergent evolution of their brains. Even superficial examination reveals major anatomical differences between mammalian and avian brains, such as extensive development of the optic lobes and cerebellum in birds and a highly developed cortex in mammals. It has been nearly impossible to identify avian homologs of some mammalian brain regions by standard morphological criteria. This has long frustrated efforts at clarifying hypotheses regarding the anatomical location, field size, and regulation of brain functions shared between these two classes, despite the certainty that the principles of neurobiology apply equally at the cellular level in both groups. In an effort to remove this barrier, we have sought markers of common function that despite apparent anatomical dissimilarity, can allow recognition of homologous brain structures. We illustrate here how comparative analysis of the distribution of the steroid-metabolizing enzyme estrogen synthetase (aromatase) may help to understand the differences and similarities in the limbic system and hypothalamus of birds and mammals.

Mouse ascites golgi (MAG) mucin expression and regulation by progesterone in the rat uterus

OBJECTIVE

To study the regulation of the blood group A-related high-molecular weight mucin glycoprotein epitope (mouse ascites golgi, MAG)-a menstrual cycle-dependent marker of endometrial receptivity-in a non-human endometrium model.

METHODS

Immature Sprague-Dawley rats were injected with 1 microg of estradiol, 100 microg of testosterone, 100 microg of dexamethasone, 2.5 mg of progesterone (P), 0.325 mg of RU486, P and RU486, 100 microg of tamoxifen, or vehicle for 3 days, sacrificed, and the uteri were stained for MAG. Immunohistochemistry and blood analysis were the measurements used to compare the specimens from the exogenous hormonal and endogenous hormonal groups. Electron microscopy was used to locate the MAG epitope in one pseudopregnant adult Sprague-Dawley rat.

RESULTS

The MAG epitope was present in endometrial glands of Sprague-Dawley rats, with maximal expression during proestrus and diestrus. Electron microscopy confirmed the Golgi location of this MAG epitope. In the untreated group, less than 0.5% of endometrial glands stained for MAG. The MAG was seen only in the glands of the P-treated rats and RU486 blunted this stimulatory effect by more than 95%. As little as 0.1 mg of P promoted MAG expression, with maximal response at 2.5 mg. Staining was seen 24 hours after P treatment, peaked at 72 hours, then declined. Induction of endogenous P by superovulation with pregnant mare serum gonadotropin (PMSG) and hCG (pseudopregnancy) also resulted in strong MAG glandular staining.

CONCLUSION

Our results suggest that the MAG epitope is cyclically expressed and induced by P in rat endometrial glands.

Estrogen and the aging brain

Evidence is presented indicating a role for estrogen in the function and maintenance of the aging brain. Based on complementary data that estrogen regulates the function of the immune--brain barrier, the hypothesis is presented that estrogen contributes to brain homeostasis via regulation of microglial activation, enabling immune-privileged status in the brain. Diminished estrogen levels during the menopause compromise the immune--brain barrier fostering inflammatory processes in the brain. This has potentially lethal consequences for brain cells, and may contribute to brain pathologies such as Alzheimer's disease.

Tissue-specific synthesis and oxidative metabolism of estrogens

Estrogen exposure represents the major known risk factor for development of breast cancer in women and is implicated in the development of prostate cancer in men. Human breast tissue has been shown to be a site of oxidative metabolism of estrogen due to the presence of specific cytochrome P450 enzymes. The oxidative metabolism of 17beta-estradiol (E2) to E2-3,4-quinone metabolites by an E2-4-hydroxylase in breast tissue provides a rational hypothesis to explain the mammary carcinogenic effects of estrogen in women because this metabolite is directly genotoxic and can undergo redox cycling to form genotoxic reactive oxygen species. In this chapter, evidence in support of this hypothesis and of the role of P4501B1 as the 4-hydroxylase expressed in human breast tissue is reviewed. However, the plausibility of this hypothesis has been questioned on the grounds that insufficient E2 is present in breast tissue to be converted to biologically significant amounts of metabolite. This critique is based on the assumption that plasma and tissue E2 levels are concordant. However, breast cancer tissue E2 levels are 10-fold to 50-fold higher in postmenopausal women than predicted from plasma levels. Consequently, factors must be present to alter breast tissue E2 levels independently of plasma concentrations. One such factor may be the local production of E2 in breast tissue through the enzyme aromatase, and the evidence supporting the expression of aromatase in breast tissue is also reviewed in this chapter. If correct, mutations or environmental factors enhancing aromatase activity might result in high tissue concentrations of E2 that would likely be sufficient to serve as substrates for CYP1B1, given its high affinity for E2. This concept, if verified experimentally, would provide plausibility to the hypothesis that sufficient E2 may be present in tissue for formation of catechol metabolites that are estrogenic and which, upon further oxidative metabolism, form genotoxic species at levels that may contribute to estrogen carcinogenesis.

Oestrogen-induced changes in the synaptology of the monkey (Cercopithecus aethiops) arcuate nucleus during gonadotropin feedback

To assess their role in the regulation of gonadotropin secretion in primates, we determined the number of synaptic connections on gondotropin releasing hormone (GnRH)- and non-GnRH neurones of the arcuate nucleus of ovariectomized (OVX) and OVX plus oestradiol benzoate-treated African green monkeys. After 24 h (day 1), 48 h (day 2) and 8 days (day 8), we performed immunostaining for GnRH. Using electron microscopy, synapses on GnRH- and randomly selected non-GnRH neurones were counted and characterized according to the classification of Gray (symmetric/inhibitory or asymmetric/excitatory). Serum concentrations of oestradiol (OVX) needed to 232 pg/ml on day 1, 63 pg/ml on day 2 and 45 pg/ml on day 8. Concentrations of luteinizing hormone (LH) fell after ovariectomy to 9 microg/ml on day 1, surged to 93 microg/ml on day 2 and declined again by day 8. (a) Ten days after ovariectomy, there were no synapses on GnRH neurones, whereas non-GnRH cells received substantial inhibitory innervation and moderate excitatory input. (b) On day 1, GnRH neurones had highest numbers of inhibitory synapses, while inhibitory synapses on non-GnRH neurones decreased, whereas numbers of excitatory synapses remained relatively unchanged compared to OVX monkeys. (c) By day 2, synapses on GnRH neurones decreased, while synapses increased on non-GnRH cells compared to day 1. (d) On day 8, the most pronounced alteration on GnRH cells was an elevated inhibitory input while non-GnRH neurones received the fewest synapses compared to day 2. We conclude that during an oestrogen-induced LH surge, synapses on GnRH- and mixed non-GnRH neurones are differentially regulated. These findings suggest that oestrogen modulation of arcuate nucleus synapses may be important in the regulation of gonadotropin secretion in monkeys.

Estrogen is essential for maintaining nigrostriatal dopamine neurons in primates: implications for Parkinson's disease and memory

There are sexual differences in several parameters of the nigrostriatal dopamine neurons, as well as in the progression of diseases associated with this system, e.g., Parkinson's disease and dementia. These differences, as well as direct experimental data in rodents, suggest that gonadal hormones play a role in modulating this system. To determine whether circulating estrogen might have long-term effects by altering the number of dopamine neurons, the density of dopamine neurons was calculated in the compact zone of the substantia nigra of male and intact female short- (10 d) and longer-term (30 d) ovariectomized and short- and longer-term ovariectomized but estrogen-replaced nonhuman primates (African green monkeys). Furthermore, the number of tyrosine hydroxylase-expressing neurons, the total number of all types of neurons, and the volume of the compact zone of the substantia nigra were calculated in 30 d ovariectomized and in 30 d ovariectomized and estrogen-replaced monkeys. Unbiased stereological analyses demonstrated that a 30 d estrogen deprivation results in an apparently permanent loss of >30% of the total number of substantia nigra dopamine cells. Furthermore, the density calculations showed that brief estrogen replacement restores the density of tyrosine hydroxylase-immunoreactive cells after a 10 d, but not after a 30 d, ovariectomy. Moreover, the density of dopamine cells is higher in females than in males. These observations show the essential role of estrogen in maintaining the integrity of the nigral dopamine system, suggest a new treatment strategy for patients with Parkinson's disease and with certain forms of memory-impairing disorders, and provide another rationale for estrogen replacement therapy for postmenopausal women.

Roles of Fas and Fas ligand during mammary gland remodeling

Mammary involution is associated with degeneration of the alveolar structure and programmed cell death of mammary epithelial cells. In this study, we evaluated the expression of Fas and Fas ligand (FasL) in the mammary gland tissue and their possible role in the induction of apoptosis of mammary cells. FasL-positive cells were observed in normal mammary epithelium from pregnant and lactating mice, but not in nonpregnant/virgin mouse mammary tissue. Fas expression was observed in epithelial and stromal cells in nonpregnant mice but was absent during pregnancy. At day 1 after weaning, high levels of both Fas and FasL proteins and caspase 3 were observed and coincided with the appearance of apoptotic cells in ducts and glands. During the same period, no apoptotic cells were found in the Fas-deficient (MRL/lpr) and FasL-deficient (C3H/gld) mice. Increase in Fas and FasL protein was demonstrated in human (MCF10A) and mouse (HC-11) mammary epithelial cells after incubation in hormone-deprived media, before apoptosis was detected. These results suggest that the Fas-FasL interaction plays an important role in the normal remodeling of mammary tissue. Furthermore, this autocrine induction of apoptosis may prevent accumulation of cells with mutations and subsequent neoplastic development. Failure of the Fas/FasL signal could contribute to tumor development.

Mitochondrial uncoupling protein 2 (UCP2) in the nonhuman primate brain and pituitary

Energy dissipating mechanisms and their regulatory components represent key elements of metabolism and may offer novel targets in the treatment of metabolic disorders, such as obesity and diabetes. Recent studies have shown that a mitochondrial uncoupling protein (UCP2), which uncouples mitochondrial oxidation from phosphorylation, is expressed in the rodent brain by neurons that are known to regulate autonomic, metabolic, and endocrine processes. To help establish the relevance of these rodent data to primate physiology, we now examined UCP2 messenger RNA and peptide expressions in the brain and pituitary gland of nonhuman primates. In situ hybridization histochemistry showed that UCP2 messenger RNA is expressed in the paraventricular, supraoptic, suprachiasmatic, and arcuate nuclei of the primate hypothalamus and also in the anterior lobe of the pituitary gland. Immunocytochemistry revealed abundant UCP2 expression in cell bodies and axonal processes in the aforementioned nuclei as well as in other hypothalamic and brain stem regions and all parts of the pituitary gland. In the hypothalamus, UCP2 was coexpressed with neuropeptide Y, CRH, oxytocin, and vasopressin. In the pituitary, vasopressin and oxytocin-producing axonal processes in the posterior lobe and POMC cells in the intermediate and anterior lobes expressed UCP2. On the other hand, none of the GH-producing cells of the anterior pituitary was found to produce UCP2. The abundance and distribution pattern of UCP2 in the primate brain and pituitary suggest that this protein is evolutionary conserved and may relate to central autonomic, endocrine and metabolic regulation.

AMPA receptors colocalize with neuropeptide-Y- and galanin-containing, but not with dopamine, neurons of the female rat arcuate nucleus: a semiquantitative immunohistochemical colocalization study

It is well established that excitatory amino acid (EAA) neurotransmission is an essential component in the regulation of the gonadotropin-releasing hormone (GnRH) delivery system. However, the morphological interconnection of these systems is not fully understood. The objective of the present study was to determine whether or not alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors--as indicators of aspartate/glutamatergic innervation--are present in the major neuronal populations, such as the neuropeptide-Y-(NPY), galanin- (GAL) and tyrosine-hydroxylase- (TH) containing neurons of the arcuate nucleus (AN) of the female rat. Colocalization experiments using the "mirror" technique demonstrated that: (1) AN neurons containing GluR1 are also immunoreactive (IR) for GluR2/3; (2) 38.32% of AMPA-IR cells contain NPY and 31.72% of AMPA-containing neurons are also IR for GAL; in turn, 79.41% of NPY- and 56.19% of GAL-containing neurons are IR for AMPA receptors; none of the neurons are IR for both AMPA receptors and TH. These data suggest that an excitatory aspartate/glutamatergic input is implicated in the regulation of the examined neuropeptide-containing AN neurons but not in that of TH-IR cells of the same area.

Regulation of fas ligand expression in breast cancer cells by estrogen: functional differences between estradiol and tamoxifen

During neoplastic growth and metastasis, the immune system responds to the tumor by developing both cellular and humoral immune responses. In spite of this active response, tumor cells escape immune surveillance. We previously showed that FasL expression by breast tumor plays a central role in the induction of apoptosis of infiltrating Fas-immune cells providing the mechanism for tumor immune privilege. In the present study, we showed that FasL in breast tissue is functionally active, and estrogen and tamoxifen regulate its expression. We identified an estrogen recognizing element like-motif in the promoter region of the FasL gene, suggesting direct estrogen effects on FasL expression. This was confirmed by an increase in FasL expression in both RNA and protein levels in hormone sensitive breast cancer cells treated with estradiol. This effect is receptor mediated since tamoxifen blocked the estrogenic effect. Interestingly, tamoxifen also inhibited FasL expression in estrogen-depleted conditions. Moreover, an increase in FasL in breast cancer cells induces apoptosis in Fas bearing T cells and, tamoxifen blocks the induction of apoptosis. These studies provide evidence that tamoxifen inhibits FasL expression, allowing the killing of cancer cells by activated lymphocytes. This partially explains the protective effect of tamoxifen against breast cancer.

Estrogen effects on tyrosine hydroxylase-immunoreactive cells in the ventral mesencephalon of the female rat: further evidence for the two cell hypothesis of dopamine function

The present study was undertaken to examine the differential effect of estrogen (E) on the expression of tyrosine hydroxylase (TH) in the substantia nigra compacta (SNc) and in two subdivisions of the ventral tegmental area in ovariectomized (ovx) and ovx plus estradiol benzoate (ovx+E)-treated female rats. Cell counting of TH-immunoreactive perikarya of the SNc, paranigral (PN) and interfascicular (IF) nucleus was performed and compared. Our findings demonstrate that E eliminated TH immunoreactivity from a number of midbrain neurons, while it seemingly did not affect it in others. This signifies a differential effect of E on ventral mesencephalic dopaminergic neurons.

Estrogen-regulated developmental neuronal apoptosis is determined by estrogen receptor subtype and the Fas/Fas ligand system

Adult sexual dimorphism in neuronal cell number is controlled by estrogen exposure during a tightly defined period of rat brain development. The mechanisms of estrogen's effect are unknown; one possibility is regulation of programmed cell death (apoptosis). In this study we have shown that estradiol can function as a neuroprotective agent or an inducer of apoptosis, depending on the estrogen receptor-subtype present in the cell. Thus, ERalpha has a neuroprotective effect, while ERbeta mediates the induction of apoptosis in neuronal cells. Moreover, we show that estrogen-induced apoptosis through ER-beta requires the expression of Fas- and Fas ligand (FasL) proteins, since the absence of FasL in neurons prevents this effect. Furthermore, we demonstrate that microglia-secreted products induce the expression of FasL necessary to mediate estradiol-ERbeta apoptotic effect. These findings may explain the dichotomous effect of fetal estradiol on the adult neuronal number.

Estrogen-regulated developmental neuronal apoptosis is determined by estrogen receptor subtype and the Fas/Fas ligand system

Adult sexual dimorphism in neuronal cell number is controlled by estrogen exposure during a tightly defined period of rat brain development. The mechanisms of estrogen's effect are unknown; one possibility is regulation of programmed cell death (apoptosis). In this study we have shown that estradiol can function as a neuroprotective agent or an inducer of apoptosis, depending on the estrogen receptor-subtype present in the cell. Thus, ERalpha has a neuroprotective effect, while ERbeta mediates the induction of apoptosis in neuronal cells. Moreover, we show that estrogen-induced apoptosis through ER-beta requires the expression of Fas- and Fas ligand (FasL) proteins, since the absence of FasL in neurons prevents this effect. Furthermore, we demonstrate that microglia-secreted products induce the expression of FasL necessary to mediate estradiol-ERbeta apoptotic effect. These findings may explain the dichotomous effect of fetal estradiol on the adult neuronal number.

Ezrin, a membrane-cytoskeletal linking protein, is involved in the process of invasion of endometrial cancer cells

In order to study ezrin function in tumor growth and invasion, we used two cell lines of human endometrial cancers. Ishikawa, the low-metastatic endometrial cancer cell line, and its subclone (mEIIL) with high-metastatic activity and higher ezrin expression were treated with a ezrin antisense phosphorothioate oligonucleotides (ePONs) pulse four times before the in vitro growth assay and Matrigel invasion assay. ePONs significantly suppressed the number of both cells that penetrated through Matrigel membrane (inhibition rate; 40.1 +/- 7.5% (Ishikawa), 42.7 +/- 2.4% (mEIIL), mean +/- SD, n = 6, P < 0.05, Student's t-test), whereas they showed no effect on cell proliferation. Ezrin expression at the protein level was inhibited by ePONs. These data suggest that ezrin expression is required for invasion. The association of high ezrin expression in mEIIL and its higher ability to migrate through Matrigel may at least in part indicate functional significance of ezrin in endometrial cancer metastasis.

Estrogen and microglia: A regulatory system that affects the brain

Sex hormones are involved in the physiological regulation of several aspects of behavior and neuroendocrine events. It has been accepted that such effects are mediated directly by steroid actions on neurons; however, new studies have shown that the glial cells are also affected by gonadal steroids. The microglia are one specialized brain glial cell type, which is a target for estrogen actions. In fact, we believe that many of the immune and nonimmune regulatory functions of microglia in the brain are influenced directly by estrogen via expression and secretion of cytokines, and growth factors by the microglia. The present review details only a section of the known aspects of microglial function, focusing mainly on nonimmune regulatory actions in the brain and their functional relationship with sex hormones. Moreover, we present evidence for the presence of estrogen receptor-beta (ERbeta) in rat microglial cells.