Lung dysfunction causes systemic hypoxia in estrogen receptor beta knockout (ERbeta-/-) mice

Estrogen-dependent gene regulation: Molecular basis of TIMP-1 as a sex-specific biomarker for acute lung injury

Increased circulating tissue inhibitor of metalloproteinases-1 (TIMP-1) levels have been observed in patients with acute lung injury (ALI). However, the sex-specific regulation of TIMP-1 and the underlying molecular mechanisms have not been well elucidated. In this study, we found that plasma TIMP-1 levels were significantly higher in COVID-19 and H1N1 patients compared with those in healthy subjects (n = 25). TIMP-1 concentrations were significantly different between males and females in each disease group. Among female but not male patients, TIMP-1 levels significantly correlated with the PaO2/FiO2 ratio and hospital length of stay. Using the mouse model of ALI induced by the H1N1 virus, we found that TIMP-1 is strikingly induced in PDGFRα-positive cells in the murine lungs. Moreover, female mice showed a higher Timp-1 expression in the lungs on day 3 postinfection. Mechanistically, we observed that estrogen can upregulate TIMP-1 expression in lung fibroblasts, not epithelial cells. In addition, overexpression of estrogen receptor α (ERα) increased the TIMP-1 promoter activity. In summary, TIMP-1 is an estrogen-responsive gene, and its promoter activity is regulated by ERα. Circulating TIMP-1 may serve as a sex-specific marker, reflecting the severity and worst outcomes in female patients with SARS-CoV2- and IAV-related ALI.

Diosmetin as a promising natural therapeutic agent: In vivo, in vitro mechanisms, and clinical studies

Diosmetin, a natural occurring flavonoid, is primarily found in citrus fruits, beans, and other plants. Diosmetin demonstrates a variety of pharmacological activities, including anticancer, antioxidant, anti-inflammatory, antibacterial, metabolic regulation, cardiovascular function improvement, estrogenic effects, and others. The process of literature search was done using PubMed, Web of Science and ClinicalTrials databases with search terms containing Diosmetin, content, anticancer, anti-inflammatory, antioxidant, pharmacological activity, pharmacokinetics, in vivo, and in vitro. The aim of this review is to summarize the in vivo, in vitro and clinical studies of Diosmetin over the last decade, focusing on studies related to its anticancer, anti-inflammatory, and antioxidant activities. It is found that DIO has significant therapeutic effects on skin and cardiovascular system diseases, and its research in pharmacokinetics and toxicology is summarized. It provides the latest information for researchers and points out the limitations of current research and areas that should be strengthened in future research, so as to facilitate the relevant scientific research and clinical application of DIO.

Do Ultrasound Lung Abnormalities Correlate to Biomarkers and Male Gender in Rheumatoid Arthritis Patients? A Monocentric Cross-Sectional Study

Background: Lung ultrasound (LUS) is a tool of growing interest in Rheumatoid Arthritis (RA) oligo- symptomatic ILD to avoid. Objective: We aimed to evaluate (i) the prevalence of pleural (PLUS) and parenchymal (PAUS) abnormalities in LUS in the RA population and their possible correlation to biomarkers; (ii) the predictivity of gender, smoking habits, previous infections (past COVID-19 tuberculosis), and treatments; (iii) the differences in LUS between sexes. Methods: We collected the data of 155 (15 early and 140 late) RA patients with mild respiratory symptoms, evaluating PLUS and PAUS, in fourteen lung areas and also summing the scores (LUS-T). Results: Only 13/155 (8.4%) were completely negative; LUS correlated to age (all parameters p 0.0001), rheumatoid factor IgM (PLUS p 0.0006, PAUS p 0.02, LUS-T p 0.001) and ACPA (p 0.001, 0.006, 0.001, respectively), and PLUS also correlated to IL6 (p 0.02). The male gender was predictive of all LUS evaluations (p 0.001, 0.05, 0.001, respectively), which were higher than in women (p 0.001, 0.01, 0.001, respectively). Other potential risk factors were independent, except biological treatments, which showed a low predictivity to PLUS (p < 0.05). Conclusions: We can conclude that LUS is a useful technique in RA low respiratory symptoms and correlates with age, the most important RA biomarkers, and male sex.

The novel molecular mechanism of pulmonary fibrosis: insight into lipid metabolism from reanalysis of single-cell RNA-seq databases

Pulmonary fibrosis (PF) is a severe pulmonary disease with limited available therapeutic choices. Recent evidence increasingly points to abnormal lipid metabolism as a critical factor in PF pathogenesis. Our latest research identifies the dysregulation of low-density lipoprotein (LDL) is a new risk factor for PF, contributing to alveolar epithelial and endothelial cell damage, and fibroblast activation. In this study, we first integrative summarize the published literature about lipid metabolite changes found in PF, including phospholipids, glycolipids, steroids, fatty acids, triglycerides, and lipoproteins. We then reanalyze two single-cell RNA-sequencing (scRNA-seq) datasets of PF, and the corresponding lipid metabolomic genes responsible for these lipids' biosynthesis, catabolism, transport, and modification processes are uncovered. Intriguingly, we found that macrophage is the most active cell type in lipid metabolism, with almost all lipid metabolic genes being altered in macrophages of PF. In type 2 alveolar epithelial cells, lipid metabolic differentially expressed genes (DEGs) are primarily associated with the cytidine diphosphate diacylglycerol pathway, cholesterol metabolism, and triglyceride synthesis. Endothelial cells are partly responsible for sphingomyelin, phosphatidylcholine, and phosphatidylethanolamines reprogramming as their metabolic genes are dysregulated in PF. Fibroblasts may contribute to abnormal cholesterol, phosphatidylcholine, and phosphatidylethanolamine metabolism in PF. Therefore, the reprogrammed lipid profiles in PF may be attributed to the aberrant expression of lipid metabolic genes in different cell types. Taken together, these insights underscore the potential of targeting lipid metabolism in developing innovative therapeutic strategies, potentially leading to extended overall survival in individuals affected by PF.

Genistein alleviates pulmonary fibrosis by inactivating lung fibroblasts

Pulmonary fibrosis is a serious lung disease that occurs predominantly in men. Genistein is an important natural soybeanderived phytoestrogen that affects various biological functions, such as cell migration and fibrosis. However, the antifibrotic effects of genistein on pulmonary fibrosis are largely unknown. The antifibrotic effects of genistein were evaluated using in vitro and in vivo models of lung fibrosis. Proteomic data were analyzed using nano-LC-ESI-MS/MS. Genistein significantly reduced transforming growth factor (TGF)-β1-induced expression of collagen type I and α-smooth muscle actin (SMA) in MRC-5 cells and primary fibroblasts from patients with idiopathic pulmonary fibrosis (IPF). Genistein also reduced TGF-β1-induced expression of p-Smad2/3 and p-p38 MAPK in fibroblast models. Comprehensive protein analysis confirmed that genistein exerted an anti-fibrotic effect by regulating various molecular mechanisms, such as unfolded protein response, epithelial mesenchymal transition (EMT), mammalian target of rapamycin complex 1 (mTORC1) signaling, cell death, and several metabolic pathways. Genistein was also found to decrease hydroxyproline levels in the lungs of BLM-treated mice. Genistein exerted an anti-fibrotic effect by preventing fibroblast activation, suggesting that genistein could be developed as a pharmacological agent for the prevention and treatment of pulmonary fibrosis. [BMB Reports 2024; 57(3): 143-148].

Liver X receptors and estrogen receptor β, two players in a rare subtype of NSCLC

Liver X receptors (LXRαβ) play essential roles in the maintenance of the normal functions of macrophages, in modulation of immune system responses and cholesterol homeostasis. We have reported that LXRαβ^-/- mice develop squamous cell lung cancer. We now report that those LXRαβ^-/- mice, which live to 18-months of age, spontaneously develop a second type of lung cancer resembling a rare subtype of NSCLC (TTF-1 and P63-positive). The lesions are characterized as follows: a high proliferation rate; a marked accumulation of abnormal macrophages; an increase in the number of regulatory T cells; a remarkably low level of CD8⁺ cytotoxic T lymphocytes; enhanced TGFβ signaling; an increased expression of matrix metalloproteinases accompanied by degradation of lung collagen; and a loss of estrogen receptor β (ERβ). Because NSCLC is associated with cigarette smoking, we investigated the possible links between loss of LXRαβ and CS. A Kaplan-Meier Plotter database revealed reduced expression of LXRαβ and ERβ was correlated with low overall survival (OS). Thus, reduction of LXRαβ expression by cigarette smoking may be one mechanism through which CS causes lung cancer. The possibility that maintenance of LXRαβ and ERβ signaling could be used in the treatment of NSCLC needs further investigation.

Associations between urinary parabens and lung cancer

Parabens are a family of endocrine-disrupting chemicals. Environmental estrogens may play a vital role in the development of lung cancer. To date, the association between parabens and lung cancer is unknown. Based on the 189 cases and 198 controls recruited between 2018 and 2021 in Quzhou, China, we measured 5 urinary parabens concentrations and examined the association between urinary concentrations of parabens and lung cancer risk. Cases showed significantly higher median concentrations of methyl-paraben (MeP) (2.1 versus 1.8 ng/mL), ethyl-paraben (0.98 versus 0.66 ng/mL), propyl-paraben (PrP) (2.2 versus 1.4 ng/mL), and butyl-paraben (0.33 versus 0.16 ng/mL) than controls. The detection rates of benzyl-paraben were only 8 and 6% in the control and case groups, respectively. Therefore, the compound was not considered in the further analysis. The significant correlation between urinary concentrations of PrP and the risk of lung cancer (odds ratio (OR)_adjusted = 2.22, 95% confidence interval (CI): 1.76, 2.75; P_trend < 0.001) was identified in the adjusted model. In the stratification analysis, we found that urinary concentrations of MeP were significantly associated with lung cancer risk (OR = 1.16, 95% CI: 1.01, 1.27 for the highest quartile group). Besides, comparing the second, third, and fourth quartile groups with the lowest group of PrP, we also observed urinary PrP concentrations associated with lung cancer risk, with the adjusted OR of 1.52 (95% CI: 1.29, 1.65, P_trend = 0.007), 1.39 (95% CI: 1.15, 1.60, P_trend = 0.010), and 1.85 (95% CI: 1.53, 2.30, P_trend = 0.001), respectively. MeP and PrP exposure, reflected in urinary concentrations of parabens, may be positively associated with the risk of lung cancer in adults.

Optimized Mouse-on-mouse Immunohistochemical Detection of Mouse ESR2 Proteins with PPZ0506 Monoclonal Antibody

Despite the physiological significance of ESR2, a lack of well-validated detection systems for ESR2 proteins has hindered progress in ESR2 research. Thus, recent identification of a specific anti-human ESR2 monoclonal antibody (PPZ0506) and its specific cross-reactivity against mouse and rat ESR2 proteins heightened momenta toward development of appropriate immunohistochemical detection systems for rodent ESR2 proteins. Building upon our previous optimization of ESR2 immunohistochemical detection in rats using PPZ0506, in this study, we further aimed to optimize mouse-on-mouse immunohistochemical detection using PPZ0506. Our assessment of several staining conditions using paraffin-embedded ovary sections revealed that intense heat-induced antigen retrieval, appropriate blocking, and appropriate antibody dilutions were necessary for optimization of mouse-on-mouse immunohistochemistry. Subsequently, we applied the optimized immunostaining method to determine expression profiles of mouse ESR2 proteins in peripheral tissues and brain subregions. Our analyses revealed more localized distribution of mouse ESR2 proteins than previously assumed. Moreover, comparison of these results with those obtained in humans and rats using PPZ0506 revealed interspecies differences in ESR2 expression. We expect that our optimized methodology for immunohistochemical staining of mouse ESR2 proteins will help researchers to solve multiple lines of controversial evidence concerning ESR2 expression.

Role of estrogen receptors in health and disease

Estrogen receptors (ERs) regulate multiple complex physiological processes in humans. Abnormal ER signaling may result in various disorders, including reproductive system-related disorders (endometriosis, and breast, ovarian, and prostate cancer), bone-related abnormalities, lung cancer, cardiovascular disease, gastrointestinal disease, urogenital tract disease, neurodegenerative disorders, and cutaneous melanoma. ER alpha (ERα), ER beta (ERβ), and novel G-protein-coupled estrogen receptor 1 (GPER1) have been identified as the most prominent ERs. This review provides an overview of ERα, ERβ, and GPER1, as well as their functions in health and disease. Furthermore, the potential clinical applications and challenges are discussed.

Targeting Estrogens and Various Estrogen-Related Receptors against Non-Small Cell Lung Cancers: A Perspective

Non-small cell lung cancers (NSCLCs) account for ~85% of lung cancer cases worldwide. Mammalian lungs are exposed to both endogenous and exogenous estrogens. The expression of estrogen receptors (ERs) in lung cancer cells has evoked the necessity to evaluate the role of estrogens in the disease progression. Estrogens, specifically 17β-estradiol, promote maturation of several tissue types including lungs. Recent epidemiologic data indicate that women have a higher risk of lung adenocarcinoma, a type of NSCLC, when compared to men, independent of smoking status. Besides ERs, pulmonary tissues both in healthy physiology and in NSCLCs also express G-protein-coupled ERs (GPERs), epidermal growth factor receptor (EGFRs), estrogen-related receptors (ERRs) and orphan nuclear receptors. Premenopausal females between the ages of 15 and 50 years synthesize a large contingent of estrogens and are at a greater risk of developing NSCLCs. Estrogen-ER/GPER/EGFR/ERR-mediated activation of various cell signaling molecules regulates NSCLC cell proliferation, survival and apoptosis. This article sheds light on the most recent achievements in the elucidation of sequential biochemical events in estrogen-activated cell signaling pathways involved in NSCLC severity with insight into the mechanism of regulation by ERs/GPERs/EGFRs/ERRs. It further discusses the success of anti-estrogen therapies against NSCLCs.

Estrogen Receptor ß in Cancer: To ß(e) or not to ß(e)?

Estrogen receptors (ERs) are known to play an important role in the proper development of estrogen-sensitive organs, as well as in the development and progression of various types of cancer. ERα, the first ER to be discovered, has been the focus of most cancer research, especially in the context of breast cancer. However, ERβ expression also plays a significant role in cancer pathophysiology, notably its seemingly protective nature and loss of expression with oncogenesis and progression. Although ERβ exhibits antitumor activity in breast, ovarian, and prostate cancer, its expression is associated with disease progression and worse prognosis in lung cancer. The function of ERβ is complicated by the presence of multiple isoforms and single nucleotide polymorphisms, in addition to tissue-specific functions. This mini-review explores current literature on ERβ and its mechanism of action and clinical implications in breast, ovarian, prostate, and lung cancer.

Interstitial Lung Diseases and the Impact of Gender

Interstitial lung diseases encompass an amalgamated group of heterogeneous lung disorders, characterized by variable clinical and radiologic patterns. Despite an increase in our knowledge, pathogenesis of interstitial lung diseases remains largely unknown. Experimental evidence on the role of sex hormones in lung development and epidemiologic associations of gender differences with interstitial lung diseases prevalence fueled studies investigating the role of gender and sex hormones in the pathogenesis and treatment of pulmonary fibrosis. This review summarizes experimental and clinical data for the impact of gender and sex hormones on interstitial lung diseases and highlights future perspectives in the field.

The smoking estrogens - a potential synergy between estradiol and benzo(a)pyrene

According to recent statistics, Lung Cancer (LC) is one of the most frequently diagnosed tumor types, representing nearly 12% of all global cancer cases. Moreover, in recent years, an increased mortality rate and incidence of this cancer were observed, especially among nonsmokers. Lung cancer patients are often characterized by poor prognosis and low survival rates, which encourages the scientific community to investigate the biochemical and molecular processes leading to the development of this malignancy. Furthermore, the mechanisms of LC formation and progression are not yet fully elucidated due to their high complexity, as well as a multitude of environmental, genetic, and molecular factors involved. Even though LC's association with exposure to cigarette smoke is indisputable, current research provides evidence that the development of this cancer can also be affected by the presence of estrogens and their interaction with several tobacco smoke components. Hence, the main goal of this brief review was to investigate reports of a possible synergy between 17β estradiol (E2), the most biologically active estrogen, and benzo(a)pyrene (BaP), a strongly carcinogenic compound produced as a result of incomplete tobacco combustion. The literature sources demonstrate a possible carcinogenic synergy between estrogens, especially E2, and BaP, a toxic tobacco smoke component. Therefeore, the combined effect of disturbed estrogen production in cancer cells, as well as the molecular influence exerted by BaP, could explain the increased aggressiveness and rate of LC development. Summarizing, the synergistic effect of these risk factors is an interesting area of further research.

Delta-like 4 is required for pulmonary vascular arborization and alveolarization in the developing lung

The molecular mechanisms by which endothelial cells (ECs) regulate pulmonary vascularization and contribute to alveolar epithelial cell development during lung morphogenesis remain unknown. We tested the hypothesis that delta-like 4 (DLL4), an EC Notch ligand, is critical for alveolarization by combining lung mapping and functional studies in human tissue and DLL4-haploinsufficient mice (Dll4+/lacz). DLL4 expressed in a PECAM-restricted manner in capillaries, arteries, and the alveolar septum from the canalicular to alveolar stage in mice and humans. Dll4 haploinsufficiency resulted in exuberant, nondirectional vascular patterning at E17.5 and P6, followed by smaller capillaries and fewer intermediate blood vessels at P14. Vascular defects coincided with polarization of lung EC expression toward JAG1-NICD-HES1 signature and decreased tip cell-like (Car4) markers. Dll4+/lacZ mice had impaired terminal bronchiole development at the canalicular stage and impaired alveolarization upon lung maturity. We discovered that alveolar type I cell (Aqp5) markers progressively decreased in Dll4+/lacZ mice after birth. Moreover, in human lung EC, DLL4 deficiency programmed a hypersprouting angiogenic phenotype cell autonomously. In conclusion, DLL4 is expressed from the canalicular to alveolar stage in mice and humans, and Dll4 haploinsufficiency programs dysmorphic microvascularization, impairing alveolarization. Our study reveals an obligate role for DLL4-regulated angiogenesis in distal lung morphogenesis.

Lung oxidative stress and transcriptional regulations induced by estradiol and intermittent hypoxia

We determined the effects of chronic intermittent hypoxia (CIH) and estradiol (E₂) on oxidative stress and gene expression in the lungs. Female Sprague-Dawley rats were left intact (sham) or ovariectomized (OVX) and implanted with pumps delivering vehicle or E₂ (0.5 mg/kg/day). Two weeks following surgery, the rats were exposed to room air (RA) or CIH for 7 days (10% O₂, 10 cycles/hour, 8 h/day). Lung samples were used to measure the activities of pro- (NADPH and xanthine oxidases) and antioxidant (superoxide dismutase, catalase and glutathione peroxidase) enzymes, and concentrations of advanced oxidation of protein products (AOPP). We determined gene expression with an RNA microarray and enrichment analysis of differentially expressed genes. In rats exposed to RA, OVX and E₂ supplementation increased pro- and antioxidant activities and AOPP concentration. In rats exposed to CIH, AOPP concentration, pro- and antioxidant enzymes activities increased in sham, did not changed in OVX-Veh rats, and were reduced in OVX-E₂ rats. In rats exposed to RA, genes involved in extracellular matrix were up-regulated by OVX and down-regulated by E₂, while E₂ up-regulated genes involved in cell mobility/adherence and leukocytes migration. OVX downregulated expression of roughly 200 olfactory receptor genes without effect of E₂. CIH altered gene expression in sham and OVX-E₂, but not in OVX-Veh rats. Enrichment analysis confirmed the antioxidant effects of E₂ under CIH. There are important interactions between ovarian hormones and CIH that can be relevant to better understand the consequences of sleep apnea (i.e. CIH) on the occurrence of lung pathologies in women.

Estrogen Receptor Beta (ERβ): A Ligand Activated Tumor Suppressor

Estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ) belong to a superfamily of nuclear receptors called steroid hormone receptors, which, upon binding ligand, dimerize and translocate to the nucleus where they activate or repress the transcription of a large number of genes, thus modulating critical physiologic processes. ERβ has multiple isoforms that show differing association with prognosis. Expression levels of the full length ERβ1 isoform are often lower in aggressive cancers as compared to normal tissue. High ERβ1 expression is associated with improved overall survival in women with breast cancer. The promise of ERβ activation, as a potential targeted therapy, is based on concurrent activation of multiple tumor suppressor pathways with few side effects compared to chemotherapy. Thus, ERβ is a nuclear receptor with broad-spectrum tumor suppressor activity, which could serve as a potential treatment target in a variety of human cancers including breast cancer. Further development of highly selective agonists that lack ERα agonist activity, will be necessary to fully harness the potential of ERβ.

Urinary bisphenol A and its interaction with ESR1 genetic polymorphism associated with non-small cell lung cancer: findings from a case-control study in Chinese population

Bisphenol A (BPA), a well-known endocrine disruptor, was reported to promote migration and invasion of lung cancer cells, but findings in human study is absent. A case-control study in Chinese population was conducted to evaluate the association between BPA exposure and non-small cell lung cancer (NSCLC), and explore the interaction between BPA exposure and estrogen-related genetic polymorphism on NSCLC. BPA concentrations were measured in urine samples using an UHPLC-MS method and rs2046210 in estrogen receptor α (ESR1) gene was genotyped by TaqMan genotyping system. Logistic regression was performed to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for the association analyses. As a result, 615 NSCLC cases and 615 healthy controls were enrolled from Wuhan, central China. The mean age was 58.0 (SD: 7.9) years old for controls and 59.2 (SD: 8.8) years old for cancer cases. The creatinine-adjusted BPA levels were significantly higher in NSCLC cases than that in healthy controls (median: 0.97 vs 0.73 μg/L, P < 0.001). Exposure to high levels of BPA was significantly associated with NSCLC (adjusted OR = 1.91, 95%CI: 1.39-2.62, P < 0.001 for the highest quartile). We also observed a shallow concave dose-response relationship about the overall association between BPA and NSCLC. Moreover, interaction analyses showed that BPA exposure interacted multiplicatively with rs2046210, with a marginal P value (P = 0.049), to contribute to NSCLC. In conclusion, exposure to high levels BPA may be associated with NSCLC and the relationship may be modified by genetic polymorphism in ESR1.

Estrogen Receptors Alpha and Beta in Acute Myeloid Leukemia

Estrogen receptor (ER) signaling has been widely studied in a variety of solid tumors, where the differential expression of ERα and ERβ subtypes can impact prognosis. ER signaling has only recently emerged as a target of interest in acute myeloid leukemia (AML), an aggressive hematological malignancy with sub-optimal therapeutic options and poor clinical outcomes. In a variety of tumors, ERα activation has proliferative effects, while ERβ targeting results in cell senescence or death. Aberrant ER expression and hypermethylation have been characterized in AML, making ER targeting in this disease of great interest. This review describes the expression patterns of ERα and ERβ in AML and discusses the differing signaling pathways associated with each of these receptors. Furthermore, we assess how these signaling pathways can be targeted by various selective estrogen receptor modulators to induce AML cell death. We also provide insight into ER targeting in AML and discuss pending questions that require further study.

MicroRNA let-7 Downregulates Ligand-Independent Estrogen Receptor-mediated Male-Predominant Pulmonary Fibrosis

Rationale: The relevance of hormones in idiopathic pulmonary fibrosis (IPF), a predominantly male lung disease, is unknown.Objectives: To determine whether the ER (estrogen receptor) facilitates the development of pulmonary fibrosis and is mediated in part through microRNA regulation of ERα and ERα-activated profibrotic pathways.Methods: ER expression in male lung tissue and myofibroblasts from control subjects (n = 6) and patients with IPF (n = 6), aging bleomycin (BLM)-treated mice (n = 7), and BLM-treated AF2ERKI mice (n = 7) was determined. MicroRNAs that regulate ER and fibrotic pathways were assessed. Transfections with a reporter plasmid containing the 3' untranslated region of the gene encoding ERα (ESR1) with and without miRNA let-7 mimics or inhibitors or an estrogen response element-driven reporter construct (ERE) construct were conducted.Measurements and Main Results: ERα expression increased in IPF lung tissue, myofibroblasts, or BLM mice. In vitro treatment with let-7 mimic transfections in human myofibroblasts reduced ERα expression and associated fibrotic pathways. AF2ERKI mice developed BLM-induced lung fibrosis, suggesting a role for growth factors in stimulating ER and fibrosis. IGF-1 (insulin-like growth factor 1) expression was increased and induced a fourfold increase of an ERE construct.Conclusions: Our data show 1) a critical role for ER and let-7 in lung fibrosis, and 2) that IGF may stimulate ER in an E2-independent manner. These results underscore the role of sex steroid hormones and their receptors in diseases that demonstrate a sex prevalence, such as IPF.

Targeting ERβ in Macrophage Reduces Crown-like Structures in Adipose Tissue by Inhibiting Osteopontin and HIF-1α

Proinflammatory processes in adipose tissue contribute to development of breast cancer and insulin resistance. Crown-like structures (CLS) are histologic hallmarks of the proinflammatory process in adipose tissue. CLS are microscopic foci of dying adipocytes surrounded by macrophages mostly derived from monocytes in blood. Estrogen receptor β (ERβ) is expressed in microglia, macrophages within the central nervous system (CNS), where it evokes an anti-inflammatory response. The present study investigates the function of ERβ in macrophages within CLS. We report that even though monocytes in the blood have no detectable levels of ERβ, macrophages in CLS do express ERβ. In ERβ−/− mice, there was a significant increase in the number of CLS in both subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT). CLS in these mice were dominated by pro-inflammatory macrophages (M1 macrophages) with higher expression of osteopontin (OPN) and an increase in number of proliferating macrophages. In mice made obese by Western diet, treatment with an ERβ selective agonist (LY3201) reduced the number of CLS in both SAT and VAT with downregulation of OPN, activated hypoxia-inducible factor-1α (HIF-1α), proliferation and upregulation prolyl hydroxylase 2 (PHD2), the enzyme which prevents activation of HIF1α, in macrophages. We conclude that ERβ expression is induced in macrophages in CLS within adipose tissue where it plays a pivotal role in suppression of CLS. Thus ERβ agonists may be used to alleviate CLS-related breast cancer and insulin resistance in adipose tissue.

Estrogen Receptor Beta-Mediated Modulation of Lung Cancer Cell Proliferation by 27-Hydroxycholesterol

27-hydroxycholesterol (27HC) is an abundant cholesterol metabolite in human circulation and promotes breast cancer cell proliferation. Although lung is one of the organs that contain high levels of 27HC, the role of 27HC in lung is unknown. In this study, we found that 27HC promotes lung cancer cell proliferation in an estrogen receptor β (ERβ)-dependent manner. The expression of 27HC-generating enzyme CYP27A1 is higher in lung cancer cells than in normal lung cells. Treatment with 27HC increased cell proliferation in ERβ-positive lung cancer cells, but not in ERα-positive or ER-negative cells. The effect on cell proliferation is specific to 27HC and another oxysterol, 25-hydroxycholesterol that has a similar oxysterol structure with 27HC. Moreover, among ligands for nuclear receptors tested, only estrogen had the proliferative effect, and the effect by 27HC and estrogen was inhibited by ERβ-specific, but not ERα-specific, inhibitors. In addition, the effect by 27HC was not affected by membrane-bound estrogen receptor GPR30. Interestingly, despite the high expression of CYP27A1, endogenously produced 27HC was not the major contributor of the 27HC-induced cell proliferation. Using kinase inhibitors, we found that the effect by 27HC was mediated by the PI3K-Akt signaling pathway. These results suggest that 27HC promotes lung cancer cell proliferation via ERβ and PI3K-Akt signaling. Thus, lowering 27HC levels may lead to a novel approach for the treatment of lung cancer.

Estrogen, Estrogen Receptor and Lung Cancer

Estrogen has been postulated as a contributor for lung cancer development and progression. We reviewed the current knowledge about the expression and prognostic implications of the estrogen receptors (ER) in lung cancer, the effect and signaling pathway of estrogen on lung cancer, the hormone replacement therapy and lung cancer risk and survival, the mechanistic relationship between the ER and the epidermal growth factor receptor (EGFR), and the relevant clinical trials combining the ER antagonist and the EGFR antagonist, to investigate the role of estrogen in lung cancer. Estrogen and its receptor have the potential to become a prognosticator and a therapeutic target in lung cancer. On the other hand, tobacco smoking aggravates the effect of estrogen and endocrine disruptive chemicals from the environment targeting ER may well contribute to the lung carcinogenesis. They have gradually become important issues in the course of preventive medicine.

Defining the Role of Estrogen Receptor β in the Regulation of Female Fertility

Estrogens are essential hormones for the regulation of fertility. Cellular responses to estrogens are mediated by estrogen receptor α (ESR1) and estrogen receptor β (ESR2). In mouse and rat models, disruption of Esr1 causes infertility in both males and females. However, the role of ESR2 in reproductive function remains undecided because of a wide variation in phenotypic observations among Esr2-mutant mouse strains. Regulatory pathways independent of ESR2 binding to its cognate DNA response element have also been implicated in ESR2 signaling. To clarify the regulatory roles of ESR2, we generated two mutant rat models: one with a null mutation (exon 3 deletion, Esr2ΔE3) and the other with an inframe deletion selectively disrupting the DNA binding domain (exon 4 deletion, Esr2ΔE4). In both models, we observed that ESR2-mutant males were fertile. ESR2-mutant females exhibited regular estrous cycles and could be inseminated by wild-type (WT) males but did not become pregnant or pseudopregnant. Esr2-mutant ovaries were small and differed from WT ovaries by their absence of corpora lutea, despite the presence of follicles at various stages of development. Esr2ΔE3- and Esr2ΔE4-mutant females exhibited attenuated preovulatory gonadotropin surges and did not ovulate in response to a gonadotropin regimen effective in WT rats. Similarities of reproductive deficits in Esr2ΔE3 and Esr2ΔE4 mutants suggest that DNA binding-dependent transcriptional function of ESR2 is critical for preovulatory follicle maturation and ovulation. Overall, the findings indicate that neuroendocrine and ovarian deficits are linked to infertility observed in Esr2-mutant rats.

Estrogen receptor β, a regulator of androgen receptor signaling in the mouse ventral prostate

As estrogen receptor β^-/- (ERβ^-/-) mice age, the ventral prostate (VP) develops increased numbers of hyperplastic, fibroplastic lesions and inflammatory cells. To identify genes involved in these changes, we used RNA sequencing and immunohistochemistry to compare gene expression profiles in the VP of young (2-mo-old) and aging (18-mo-old) ERβ^-/- mice and their WT littermates. We also treated young and old WT mice with an ERβ-selective agonist and evaluated protein expression. The most significant findings were that ERβ down-regulates androgen receptor (AR) signaling and up-regulates the tumor suppressor phosphatase and tensin homolog (PTEN). ERβ agonist increased expression of the AR corepressor dachshund family (DACH1/2), T-cadherin, stromal caveolin-1, and nuclear PTEN and decreased expression of RAR-related orphan receptor c, Bcl2, inducible nitric oxide synthase, and IL-6. In the ERβ^-/- mouse VP, RNA sequencing revealed that the following genes were up-regulated more than fivefold: Bcl2, clusterin, the cytokines CXCL16 and -17, and a marker of basal/intermediate cells (prostate stem cell antigen) and cytokeratins 4, 5, and 17. The most down-regulated genes were the following: the antioxidant gene glutathione peroxidase 3; protease inhibitors WAP four-disulfide core domain 3 (WFDC3); the tumor-suppressive genes T-cadherin and caveolin-1; the regulator of transforming growth factor β signaling SMAD7; and the PTEN ubiquitin ligase NEDD4. The role of ERβ in opposing AR signaling, proliferation, and inflammation suggests that ERβ-selective agonists may be used to prevent progression of prostate cancer, prevent fibrosis and development of benign prostatic hyperplasia, and treat prostatitis.

Exploring estrogenic activity in lung cancer

It is well known that a connection between xenobiotics inhalation, especially tobacco combustion and Lung Cancer development is strongly significant and indisputable. However, recent studies provide evidence indicating that another factors such as, estrogens are also involved in lung carcinoma biology and metabolism. Although the status of estrogen receptors (ER), in both cancerous and healthy lung tissue has been well documented, there is still inconclusive data with respect of which isoform of the receptor is present in the lungs. However according to several studies, ERβ appears to be predominant form. Apart from ERs, estrogens can work through a recently discovered G-coupled estrogen receptor. Binding with both types of the receptors causes a signal, which leads to i.e. enhanced cell proliferation. There are many published reports which suggest that estrogen can be synthesized in situ in lung cancer. Some disturbances in the activity and expression levels of enzymes involved in estrogen synthesis were proved. This suggests that increased amounts of sex-steroid hormones can affect cells biology and be the reason of the accelerated development and pathogenesis of lung cancer. There also exist phenomena which associate estrogenic metabolism and tobacco combustion and its carcinogenic influence on the lungs. Compounds present in cigarette smoke induce the activity of CYP1B1, the enzyme responsible for estrogenic metabolism and synthesis of their cateholic derivatives. These structures during their redox cycle are able to release reactive oxygen species or form DNA adduct, which generally leads to destruction of genetic material. This process may explain the synergistic effect of smoking and estrogens on estrogen-dependent lung cancer development.

Targeted basic research to highlight the role of estrogen and estrogen receptors in the cardiovascular system

Epidemiological, clinical and animal studies revealed that sex differences exist in the manifestation and outcome of cardiovascular disease (CVD). The underlying molecular mechanisms implicated in these sex differences are not fully understood. The reasons for sex differences in CVD are definitely multifactorial, but major evidence points to the contribution of sex steroid hormone, 17β-estradiol (E2), and its receptors, estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ). In this review, we summarize past and present studies that implicate E2 and ER as important determinants of sexual dimorphism in the physiology and pathophysiology of the heart. In particular, we give an overview of studies aimed to reveal the role of E2 and ER in the physiology of the observed sex differences in CVD using ER knock-out mice. Finally, we discuss recent findings from novel transgenic mouse models, which have provided new information on the sexual dimorphic roles of ER specifically in cardiomyocytes under pathological conditions.

Hypoxia-activated cytotoxic agent tirapazamine enhances hepatic artery ligation-induced killing of liver tumor in HBx transgenic mice

Transarterial chemoembolization (TACE) is the main treatment for intermediate stage hepatocellular carcinoma (HCC) with Barcelona Clinic Liver Cancer classification because of its exclusive arterial blood supply. Although TACE achieves substantial necrosis of the tumor, complete tumor necrosis is uncommon, and the residual tumor generally rapidly recurs. We combined tirapazamine (TPZ), a hypoxia-activated cytotoxic agent, with hepatic artery ligation (HAL), which recapitulates transarterial embolization in mouse models, to enhance the efficacy of TACE. The effectiveness of this combination treatment was examined in HCC that spontaneously developed in hepatitis B virus X protein (HBx) transgenic mice. We proved that the tumor blood flow in this model was exclusively supplied by the hepatic artery, in contrast to conventional orthotopic HCC xenografts that receive both arterial and venous blood supplies. At levels below the threshold oxygen levels created by HAL, TPZ was activated and killed the hypoxic cells, but spared the normoxic cells. This combination treatment clearly limited the toxicity of TPZ to HCC, which caused the rapid and near-complete necrosis of HCC. In conclusion, the combination of TPZ and HAL showed a synergistic tumor killing activity that was specific for HCC in HBx transgenic mice. This preclinical study forms the basis for the ongoing clinical program for the TPZ-TACE regimen in HCC treatment.

The Importance of Biological Sex and Estrogen in Rodent Models of Cardiovascular Health and Disease

Nearly one-third of deaths in the United States are caused by cardiovascular disease (CVD) each year. In the past, CVD was thought to mainly affect men, leading to the exclusion of women and female animals from clinical studies and preclinical research. In light of sexual dimorphisms in CVD, a need exists to examine baseline cardiac differences in humans and the animals used to model CVD. In humans, sex differences are apparent at every level of cardiovascular physiology from action potential duration and mitochondrial energetics to cardiac myocyte and whole-heart contractile function. Biological sex is an important modifier of the development of CVD with younger women generally being protected, but this cardioprotection is lost later in life, suggesting a role for estrogen. Although endogenous estrogen is most likely a mediator of the observed functional differences in both health and disease, the signaling mechanisms involved are complex and are not yet fully understood. To investigate how sex modulates CVD development, animal models are essential tools and should be useful in the development of therapeutics. This review will focus on describing the cardiovascular sexual dimorphisms that exist both physiologically and in common animal models of CVD.

Estrogen receptor profiling and activity in cardiac myocytes

Estrogen signaling appears critical in the heart. However a mechanistic understanding of the role of estrogen in the cardiac myocyte is lacking. Moreover, there are multiple cell types in the heart and multiple estrogen receptor (ER) isoforms. Therefore, we studied expression, localization, transcriptional and signaling activity of ERs in isolated cardiac myocytes. We found only ERα RNA (but no ERβ RNA) in cardiac myocytes using two independent methods. The vast majority of full-length ERα protein (ERα66) localizes to cardiac myocyte nuclei where it is competent to activate transcription. Alternate isoforms of ERα encoded by the same genomic locus (ERα46 and ERα36) have differential transcriptional activity in cardiac myocytes but also primarily localize to nuclei. In contrast to other reports, no ERα isoform is competent to activate MAPK or PI3K signaling in cardiac myocytes. Together these data support a role for ERα at the level of transcription in cardiac myocytes.

Inhibition of estrogen biosynthesis enhances lymphoma growth in mice

Most lymphomas show higher incidence and poorer prognosis in males compared to females. However, the endocrine contribution to this gender difference is not entirely known. Here we show that castration accelerates lymphoma growth in C57BL6 male mice grafted with murine EG7 T cell lymphoma cells. However, the androgen receptor antagonist Bicalutamide did not affect lymphoma growth, suggesting no impact of androgen receptor signaling on lymphoma progression. In contrast, inhibition of androgen-to-estrogen conversion by the aromatase inhibitor (AI) Letrozole induced faster lymphoma growth in mice, suggesting that androgens impact lymphoma growth through its conversion to estrogens. This was supported by the inability of dihydrotestosterone, which is not converted to estrogens by aromatase, to influence lymphoma growth in castrated male mice. Lymphoma growth was also stimulated in immunocompromised mice grafted with human B cell lymphoma (Granta-519) and treated with either reversible or irreversible AIs, showing that the blockage of estrogen synthesis caused enhanced growth of both murine T and human B cell lymphomas and with different AIs. Additionally, AI-treated EG7 lymphomas showed accelerated growth not only in male but also in intact female mice. Altogether, our results demonstrate that aromatase inhibition accelerates lymphoma growth but not androgens per se, highlighting a protective role of estrogens in lymphoma pathogenesis. These results also raise concern that the use of AIs in women with breast cancer might enhance lymphoma progression.

Estrogenic compounds reduce influenza A virus replication in primary human nasal epithelial cells derived from female, but not male, donors

Influenza causes an acute infection characterized by virus replication in respiratory epithelial cells. The severity of influenza and other respiratory diseases changes over the life course and during pregnancy in women, suggesting that sex steroid hormones, such as estrogens, may be involved. Using primary, differentiated human nasal epithelial cell (hNEC) cultures from adult male and female donors, we exposed cultures to the endogenous 17β-estradiol (E2) or select estrogen receptor modulators (SERMs) and then infected cultures with a seasonal influenza A virus (IAV) to determine whether estrogenic signaling could affect the outcome of IAV infection and whether these effects were sex dependent. Estradiol, raloxifene, and bisphenol A decreased IAV titers in hNECs from female, but not male, donors. The estrogenic decrease in viral titer was dependent on the genomic estrogen receptor-2 (ESR2) as neither genomic ESR1 nor nongenomic GPR30 was expressed in hNEC cultures and addition of the genomic ER antagonist ICI 182,780 reversed the antiviral effects of E2. Treatment of hNECs with E2 had no effect on interferon or chemokine secretion but significantly downregulated cell metabolic processes, including genes that encode for zinc finger proteins, many of which contain estrogen response elements in their promoters. These data provide novel insights into the cellular and molecular mechanisms of how natural and synthetic estrogens impact IAV infection in respiratory epithelial cells derived from humans.

Aromatase knockout mice reveal an impact of estrogen on drug-induced alternation of murine electrocardiography parameters

Our in vitro characterization showed that physiological concentrations of estrogen partially suppressed the I(Kr) channel current in guinea pig ventricular myocytes and the human ether-a-go-go-related gene (hERG) channel currents in CHO-K1 cells regardless of estrogen receptor signaling and revealed that the partially suppressed hERG currents enhanced the sensitivity to the hERG blocker E-4031. To obtain in vivo proof-of-concept data to support the effects of estrogen on cardiac electrophysiology, we here employed an aromatase knockout mouse as an in vivo estrogen-null model and compared the acute effects of E-4031 on cardiac electrophysiological parameters with those in wild-type mice (C57/BL6J) by recording surface electrocardiogram (ECG). The ablation of circulating estrogens blunted the effects of E-4031 on heart rate and QT interval in mice under a denervation condition. Our result provides in vivo proof of principle and demonstrates that endogenous estrogens increase the sensitivity of E-4031 to cardiac electrophysiology.

The identification of nuclear receptors associated with hepatic steatosis to develop and extend adverse outcome pathways

The development of adverse outcome pathways (AOPs) is becoming a key component of twenty-first century toxicology. AOPs provide a conceptual framework that links the molecular initiating event to an adverse outcome through organized toxicological knowledge, bridging the gap from chemistry to toxicological effect. As nuclear receptors (NRs) play essential roles for many physiological processes within the body, they are used regularly as drug targets for therapies to treat many diseases including diabetes, cancer and neurodegenerative diseases. Due to the heightened development of NR ligands, there is increased need for the identification of related AOPs to facilitate their risk assessment. Many NR ligands have been linked specifically to steatosis. This article reviews and summarizes the role of NR and their importance with links between NR examined to identify plausible putative AOPs. The following NRs are shown to induce hepatic steatosis upon ligand binding: aryl hydrocarbon receptor, constitutive androstane receptor, oestrogen receptor, glucocorticoid receptor, farnesoid X receptor, liver X receptor, peroxisome proliferator-activated receptor, pregnane X receptor and the retinoic acid receptor. A preliminary, putative AOP was formed for NR binding linked to hepatic steatosis as the adverse outcome.

Estradiol attenuates the TGF-β1-induced conversion of primary TAFs into myofibroblasts and inhibits collagen production and myofibroblast contraction by modulating the Smad and Rho/ROCK signaling pathways

The transformation of tunica albuginea-derived fibroblasts (TAFs) into myofibroblasts plays an important role in the pathological progress of Peyronie's disease (PD). However, no treatment which addresses this transformation is currently available. Estrogen has been shown to inhibit the progression of fibrosis in a number of fibrotic diseases. The aim of this study was to determine whether estrogen [17β‑estradiol (E2)] suppresses the diffentiation of primary rat TAFs into myofibroblasts in vitro. TAFs obtained from male Sprague‑Dawley rats were stimulated with either transforming growth factor‑β1 (TGF‑β1) or E2. Western blot analysis and immunofluorescence staining were used to assess changes in the expression levels of α‑smooth muscle actin (αSMA). The expression levels of additional proteins (GAPDH, p‑Smad2, Smad2, Smad4, RhoA, Rac1, ROCK1 and ROCK2) were also measured by western blot analysis. We used collagen gel assays to assess cell contractility. Additionally, the concentration of hydroxyproline in the TAF cell culture medium was detected using commercially available kits. We found that E2 reduced αSMA expression which was induced by TGF‑β1. E2 also suppressed the TGF‑β1‑induced increase in the concentration of hydroxyproline (a marker of collagen) in addition to suppressing the contraction of TAFs. The key processes affected by TGF‑β1 treatment included the phosphorylation of Smad2, ras homolog gene family, member A (RhoA) and Rho‑associated, coiled-coil containing protein kinase 2 (ROCK2); this increase in phosphorylation was inhibited by treatment with E2. Collectively, these results demonstrate that by modulating the activation of the TGF‑β1‑Smad and RhoA‑ROCK2 signaling pathways, E2 inhibited the transformation of TAFs into myofibroblasts, decreased the expression of collagen and suppressed the contraction of myofibroblasts in response to TGF-β1 stimulation.

Estrogen receptor β exon 3-deleted mouse: The importance of non-ERE pathways in ERβ signaling

In 1998, an estrogen receptor β (ERβ) knockout (KO) mouse was created by interrupting the gene at the DNA binding domain (DBD) with a neocassette. The mutant females were subfertile and there were abnormalities in the brain, prostate, lung, colon, and immune system. In 2008, another ERβ mutant mouse was generated by deleting ERβ exon 3 which encodes the first zinc finger in the DBD. The female mice of this strain were unable to ovulate but were otherwise normal. The differences in the phenotypes of the two KO strains, have led to questions about the physiological function of ERβ. In the present study, we created an ERβ exon 3-deleted mouse (ERβ-Δex3) and confirmed that the only observable defect was anovulation. Despite the two in-frame stop codons introduced by splicing between exons 2 and 4, an ERβ protein was expressed in nuclei of prostate epithelial cells. Using two different anti-ERβ antibodies, we showed that an in-frame ligand binding domain and C terminus were present in the ERβ-Δex3 protein. Moreover, with nuclear extracts from ERβ-Δex3 prostates, there was an ERβ-dependent retardation of migration of activator protein-1 response elements in EMSA. Unlike the original knockout mouse, expression of Ki67, androgen receptor, and Dachshund-1 in prostate epithelium was not altered in the ERβ-Δex3 mouse. We conclude that very little of ERβ transcriptional activity depends on binding to classical estrogen response elements (EREs).

Oestrogen receptor alpha in pulmonary hypertension

Aims

Pulmonary arterial hypertension (PAH) occurs more frequently in women with mutations in bone morphogenetic protein receptor type 2 (BMPR2) and dysfunctional BMPR2 signalling underpinning heritable PAH. We have previously shown that serotonin can uncover a pulmonary hypertensive phenotype in BMPR2^+/− mice and that oestrogen can increase serotinergic signalling in human pulmonary arterial smooth muscle cells (hPASMCs). Hence, here we wished to characterize the expression of oestrogen receptors (ERs) in male and female human pulmonary arteries and have examined the influence of oestrogen and serotonin on BMPR2 and ERα expression.

Methods and results

By immunohistochemistry, we showed that ERα, ERβ, and G-protein-coupled receptors are expressed in human pulmonary arteries localizing mainly to the smooth muscle layer which also expresses the serotonin transporter (SERT). Protein expression of ERα protein was higher in female PAH patient hPASMCs compared with male and serotonin also increased the expression of ERα. 17β-estradiol induced proliferation of hPASMCs via ERα activation and this engaged mitogen-activated protein kinase and Akt signalling. Female mice over-expressing SERT (SERT⁺ mice) develop PH and the ERα antagonist MPP attenuated the development of PH in normoxic and hypoxic female SERT⁺ mice. The therapeutic effects of MPP were accompanied by increased expression of BMPR2 in mouse lung.

Conclusion

ERα is highly expressed in female hPASMCs from PAH patients and mediates oestrogen-induced proliferation of hPASMCs via mitogen-activated protein kinase and Akt signalling. Serotonin can increase ERα expression in hPASMCs and antagonism of ERα reverses serotonin-dependent PH in the mouse and increases BMPR2 expression.

Sex steroid signaling: implications for lung diseases

There is increasing recognition that sex hormones (estrogen, progesterone, and testosterone) have biological and pathophysiological actions in peripheral, non-reproductive organs, including the lung. Clinically, sex differences in the incidence, morbidity and mortality of lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, lung cancer and pulmonary hypertension have been noted, although intrinsic sex differences vs. the roles of sex steroids are still not well-understood. Accordingly, it becomes important to ask the following questions: 1) Which sex steroids are involved? 2) How do they affect different components of the lung under normal circumstances? 3) How does sex steroid signaling change in or contribute to lung disease, and in this regard, are sex steroids detrimental or beneficial? As our understanding of sex steroid signaling in the lung improves, it is important to consider whether such information can be used to develop new therapeutic strategies to target lung diseases, perhaps in both sexes or in a sex-specific manner. In this review, we focus on the basics of sex steroid signaling, and the current state of knowledge regarding how they influence structure and function of specific lung components across the life span and in the context of some important lung diseases. We then summarize the potential for sex steroids as useful biomarkers and therapeutic targets in these lung diseases as a basis for future translational research in the area of gender and individualized medicine.

Pulmonary arterial hypertension: basis of sex differences in incidence and treatment response

Pulmonary arterial hypertension (PAH) is a complex disease characterized by elevated pulmonary arterial pressure, pulmonary vascular remodelling and occlusive pulmonary vascular lesions, leading to right heart failure. Evidence from recent epidemiological studies suggests the influence of gender on the development of PAH with an approximate female to male ratio of 4:1, depending on the underlying disease pathology. Overall, the therapeutic strategy for PAH remains suboptimal with poor survival rates observed in both genders. Endogenous sex hormones, in particular 17β oestradiol and its metabolites, have been implicated in the development of the disease; however, the influence of sex hormones on the underlying pathobiology remains controversial. Further understanding of the influence of sex hormones on the normal and diseased pulmonary circulation will be critical to our understanding the pathology of PAH and future therapeutic strategies. In this review, we will discuss the influence of sex hormones on the development of PAH and address recent controversies.

The elevated level of ERα36 is correlated with nodal metastasis and poor prognosis in lung adenocarcinoma

INTRODUCTION

ERα36 is a recently cloned variant of estrogen receptor-alpha which has been proved to play an active role in a series of malignant diseases.

METHOD

ERα36 expression was examined using immunohistochemical methods with sections from 126 resected NSCLC specimens. The immunoreactivity of ERα66 was also studied as a comparison. Kaplan-Meier method and multivariable Cox proportional hazards regression analyses were used to examine the relationship between ERα36 and survival.

RESULT

ERα36 was more highly expressed in NSCLC patients compared to ERα66. ERα36 expression has a strong correlation with histology (AC: 53/70, SCC: 16/56, P<0.000) and had a significantly positive correlation with lymphatic metastasis (P=0.014) in adenocarcinoma. High ERα36 expression was correlated with poorer overall survival (OS) (P=0.020) and disease-free survival (DFS) (P=0.024) in adenocarcinoma. Furthermore, ERα36 status was a significant independent prognostic factor of OS (P=0.018, HR: 3.142, 95% CI: 1.215-8.128) and DFS (P=0.024, HR: 2.720, 95% CI: 1.141-6.486) in lung adenocarcinoma patients.

CONCLUSION

ERα36 had a high expression mainly in adenocarcinoma and the high expression of ERα36 was strongly correlated with more advanced regional lymph node metastasis and poor survival in lung adenocarcinoma.

Targeting the estrogen pathway for the treatment and prevention of lung cancer

The estrogen signaling pathway is involved in the biology of non-small-cell lung cancer and represents a novel therapeutic target for lung cancer. This is supported by epidemiological evidence, preclinical studies and recent data from clinical trials. Antiestrogens and inhibitors of estrogen synthesis have been shown to inhibit lung tumor growth as well as prevent lung tumorigenesis in preclinical models both in vitro and in vivo. Two clinical trials testing the effectiveness of hormonal strategies in advanced non-small-cell lung cancer have recently been completed with promising results. Future work in this field should focus on identification of patients that would benefit from hormone modulators so that they can be used earlier in the course of disease or for chemoprevention.

17β-estradiol replacement reverses age-related lung disease in estrogen-deficient C57BL/6J mice

The role that estrogens play in the aging lung is poorly understood. Remodeling of the aging lung with thickening of the alveolar walls and reduction in the number of peripheral airways is well recognized. The present study was designed to address whether estrogen deficiency would affect age-associated changes in the lungs of female C57BL/6J mice. Lungs isolated from old mice (24 months old, estrogen-deficient) demonstrated decreased lung volume and decreased alveolar surface area. There was no difference in alveolar number in the lungs of old and young mice (6 months old, estrogen-replete). Estrogen replacement restored lung volume, alveolar surface area, and alveolar wall thickness to that of a young mouse. Estrogen receptor-α (ERα) protein expression increased without a change in ERβ protein expression in the lung tissue isolated from old mice. In the lungs of old mice, the number of apoptotic cells was increased as well as the activation of matrix metalloproteinase-2 and ERK. Young mice had the highest serum 17β-estradiol levels that decreased with age. Our data suggest that in the aging female mouse lung, estrogen deficiency and an increase of ERα expression lead to the development of an emphysematous phenotype. Estrogen replacement partially prevents these age-associated changes in the lung architecture by restoration of interalveolar septa. Understanding the role of estrogens in the remodeling of the lung during aging may facilitate interventions and therapies for aging-related lung disease in women.

Smoking out reproductive hormone actions in lung cancer

Experimental and population-based evidence has been steadily accumulating that steroid hormones are fundamentally involved in the biology of the lung. Both estrogen and progesterone receptors are present in normal and malignant lung tissue, and the reproductive hormones that bind these receptors have a role in lung development, lung inflammation, and lung cancer. The estrogen receptor-β (ER-β) was discovered in the 1990s as a novel form of ER that is transcribed from a gene distinct from ER-α, the receptor previously isolated from breast tissue. Interestingly, ER-β is the predominate ER expressed in normal and malignant lung tissue, whereas inflammatory cells that infiltrate the lung are known to express both ER-α and ER-β. Although there is evidence from animal models for the preferential effects of ER-β in the lungs of females, human lung tumors from males often contain comparable numbers of ER-β-positive cells and male-derived lung cancer cell lines respond to estrogens. Lung tumors from both males and females also express CYP19 (aromatase), the rate-limiting enzyme in estrogen synthesis that converts testosterone to estrone and β-estradiol. Thus, testosterone acts as a precursor for local estrogen production within lung tumors, independent of reproductive organs. This review discusses the recent literature findings about the biology of the ERs, aromatase, and the progesterone receptor in lung cancer and highlights the ongoing clinical trials and future therapeutic implications of these findings.

Estrongenic steroid hormones in lung cancer

It is becoming increasingly clear that steroid hormones are involved in the biology of many organs outside the reproductive system. Evidence has been accumulating since the mid 1990s that the lung contains receptors for both estrogen and progesterone and that these hormones have some role in lung development, pulmonary inflammation, and lung cancer. The estrogen receptor β (ERβ) is the major ER expressed in lung tissues, while inflammatory cells capable of infiltrating the lung are reported to express both ERα and ERβ. Although there is evidence in animals of preferential effects of ERβ in the lungs of females, human lung tumors from males also contain ERβ-positive cells and express aromatase, the enzyme that converts testosterone to estrogens. This review will discuss current literature findings on the role of the ERs and the progesterone receptor (PR), as well CYP19 (aromatase), the rate-limiting enzyme in the synthesis of estrogen, in lung cancer.

Estrogen receptor α and β in the normal immune system and in lymphoid malignancies

Estrogens regulate various normal and pathophysiological processes including cancers. Cellular signaling by estrogens is mediated by estrogen receptor α (ERα) and β (ERβ), respectively. Binding of agonists to the ERs affects gene transcription. The main endogenous estrogen, 17β-estradiol (E2), binds to both ERα and ERβ with similar affinity. However, the ligand-binding pocket of ERα and ERβ are slightly different which has allowed the development of selective ER ligands. Importantly, while estrogens via ERα stimulate proliferation, signaling via ERβ inhibits proliferation and promotes apoptosis. In both normal and cancer cells the ERs are co-expressed with ER splice variants which may modify the transcriptional activity of the wild-type receptors. Estrogens have prominent effects on immune functions and both ERα and ERβ are expressed in immune cells and lymphoid malignancies. With regard to lymphoid malignancies, most show estrogen influence as several epidemiological studies of lymphoid cancers demonstrate gender differences in incidence and prognosis with males being more affected. In line with these findings, recent results generated by us have shown that ERβ selective agonists inhibit growth and induce apoptosis in human and murine lymphomas in vivo in xenograft experiments. This suggests that ERβ selective agonists in the future may be useful in the treatment of lymphomas.

Regulation of physiological and metabolic function of muscle by female sex steroids

The ability of female sex steroids to regulate tissue function has long been appreciated; however, their role in the regulation of striated muscle function has received considerably less attention. The purpose of this symposium review was to document recent evidence indicating the role female sex steroids have in defining the functional characteristics of striated muscle. The presentations provide substantial evidence indicating that estrogens are critical to the physiological and metabolic regulations of striated muscle; thus, when considering women's health issues, striated muscle must included as an important target tissue along with other classically thought of estrogen-sensitive tissues.

Protective cardiovascular and renal actions of vitamin D and estrogen

Both basic science and clinical studies support the concept that vitamin D deficiency is involved in the pathogenesis of cardiovascular and renal diseases through its association with diabetes, obesity, and hypertension. Understanding the underlying mechanisms may provide a rationale for advocating adequate intake of vitamin D and calcium in all populations, thereby preventing many chronic diseases. This review explores the effect of vitamin D deficiency in the development of cardiovascular and renal diseases, and the role of vitamin D supplementation on cardiovascular outcomes. In addition, it highlights the importance of vitamin D intake for the prevention of adverse long-term health consequences, and in ways to facilitate the management of cardiovascular disease. This is particularly true for African American and postmenopausal women, who are at added risk for cardiovascular disease. We suggest that the negative cardiovascular effects of low vitamin D in postmenopausal women could be improved by a combined treatment of vitamin D and sex steroids acting through endothelium-dependent and/or -independent mechanisms, resulting in the generation of nitric oxide and calcitonin gene-related peptide (CGRP).