Comprehensive Analysis of Estrogen Receptor 1 Dysregulation in Liver Hepatocellular Carcinoma: Implications for Prognosis and Therapeutic Targeting - A Secondary Publication

The study investigates the expression pattern and regulatory mechanisms of estrogen receptor 1 (ESR1) in liver hepatocellular carcinoma (LIHC) through comprehensive bioinformatics analysis. Utilizing UALCAN and GEPIA2 databases, significant down-regulation of ESR1 expression is observed in LIHC samples compared to normal controls, indicating its potential role in tumor progression. Further analysis reveals consistent down-regulation across different clinical variables including patient age, gender, race, and various stages of LIHC, affirming the regulatory role of ESR1 in tumor development and progression. Additionally, promoter methylation analysis demonstrates hypermethylation of ESR1 in LIHC samples, negatively correlating with its expression. This association persists across different clinical parameters, emphasizing the inverse relationship between ESR1 methylation and expression levels. Survival analysis indicates that up- regulation of ESR1 is associated with better overall survival, suggesting its potential as a prognostic biomarker in LIHC. Furthermore, genetic mutation analysis using cBioPortal reveals a spectrum of alterations in ESR1, including amplification, missense mutation, deep deletion, splice mutation, and truncating mutation, highlighting the genetic complexity of ESR1 in LIHC. These findings collectively contribute to a deeper understanding of ESR1 dysregulation in LIHC and its clinical implications as a potential therapeutic target and prognostic marker.

T29C genotype polymorphism of estrogen receptor alpha is associated with initial response to interferon-alpha therapy in chronic hepatitis B patients

BACKGROUND: Virological clearance, delayed progression to cirrhosis or liver cancer, and increased survival are the long-term goals of antiviral therapy in chronic hepatitis B patients. Identification of host factors correlated with therapeutic response may contribute greatly to individual treatment. This study aimed at investigating whether T29C genotype polymorphism of estrogen receptor alpha (ESR1) is associated with the initial response to interferon-alpha (IFN-alpha) therapy in chronic hepatitis B patients. METHODS: The initial responses of 100 patients to IFN-alpha therapy were evaluated and compared by classifying them into three groups according to T29C genotype polymorphism of ESR1: T/T, TIC, and C/C genotype groups. Polymerase chain reaction-restriction fragment length polymorphism was used to analyze the genotype polymorphism in T29C. RESULTS: The frequency of initially combined response was markedly higher in both the T/T and TIC groups than in the C/C group (Z=10.326, P=0.006 and Z=26.247, P=0.000, respectively). In addition, the initial virological response was higher in the T/T and T/C groups than the C/C group (chi(2)=5.674, P=0.017 and chi(2)=4.980, P=0.026, respectively). In 78 initially HBeAg-positive patients, however, the frequency of initial e-antigen disappearance or seroconversion among the T/T, T/C, and C/C genotype groups was 34.15%, 27.78% and 15.79%, respectively, which were not significantly different. CONCLUSION. The T29C genotype polymorphism of ESR1 is associated with the initial response to IFN-alpha in patients with chronic hepatitis B, and might be a significant marker for predicting the initial response to IFN-alpha, at least in this study population. (Hepatobiliary Pancreat Dis Int 2010; 9: 275-279)

Polyubiquitination inhibition of estrogen receptor alpha and its implications in breast cancer

Estrogen receptor alpha(ERα) is detected in more than 70% of the cases of breast cancer. Nuclear activity of ERα, a transcriptional regulator, is linked to the development of mammary tumors, whereas the extranuclear activity of ERα is related to endocrine therapy resistance. ERα polyubiquitination is induced by the estradiol hormone, and also by selective estrogen receptor degraders, resulting in ERα degradation via the ubiquitin proteasome system. Moreover, polyubiquitination is related to the ERα transcription cycle, and some E3-ubiquitin ligases also function as coactivators for ERα. Several studies have demonstrated that ERα polyubiquitination is inhibited by multiple mechanisms that include posttranslational modifica-tions, intera-ctions with coregula-tors, a-nd forma-tion of specific protein complexes with ERα. These events are responsible for an increase in ERα protein levels and deregulation of its signaling in breast cancers. Thus, ERα polyubiquitination inhibition may be a key factor in the progression of breast cancer and resistance to endocrine therapy.

Effects of Estrogen-related Receptor alpha (ERRα) on Proliferation and Metastasis of Human Lung Cancer A549 Cells

Estrogen-related receptor alpha （ERRα） plays an important role in the development of hor- monezdependent cancers, but its roles in lung cancer remain elusive. The present study was aimed to investigate the effects of ERRα on the proliferation and metastasis of lung cancer A549 cells. The mRNA and protein levels of ERRor were detected in lung cancer A549 and MCF-7 cells and bronchial epithelial BEAS-2B cells by qRT-PCR and Western blotting, respectively. ERRor plasmid transfection and XCT-790 （an inverse agonist of ERRc0 were used to up-regulate or down-regulate ERRα expression in A549 cells, respectively. The viability of A549 cells was measured by cell counting kit-8 （CCK-8） and the motility of A549 cells by wound healing assay and Transwell migration/invasion assay. The epithelial markers E-cadherin （E-Cad） and zona occludin-1 （ZO-1）, the mesenchymal markers fi- bronectin （FN） and vimentin （Vim） and the transcription factors （Snail, Zebl Twist and Slug） were fur- ther detected at mRNA and protein levels by qRT-PCR and Western blotting, respectively. The results showed that ERRor promoted the growth of lung cancer A549 cells in vitro. XCT-790 significantly in- hibited the migration and invasion of A549 cells. Over-expression of ERRα promoted the epithe- lial-to-mesenchymal transition （EMT） of A549 ceils, down-regulated the epithelial makers E-Cad and ZO-1, and up-regulated the mesenchymal makers FN and Vim. Silencing of Slug, but not other tran- scription factors, significantly abolished the ERRs-induced EMT of A549 cells. It was suggested that ERRor promoted the migration and invasion of A549 cells by inducing EMT, and Slug was involved in the process. Targeting ERRor might be an efficient approach for lung cancer treatment.

Estrogen receptor alpha gene amplification in breast cancer:25 years of debate

Twenty-five years ago,Nembrot and colleagues reported amplification of the estrogen receptor alpha gene(ESR1) in breast cancer,initiating a broad and still ongoing scientific debate on the prevalence and clinical significance of this genetic aberration,which affects one of the most important genes in breast cancer.Since then,a multitude of studies on this topic has been published,covering a wide range of divergent results and arguments.The reported prevalence of this alteration in breast cancer ranges from 0% to 75%,suggesting that ESR1 copy number analysis is hampered by technical and interpreter issues.To date,two major issues related to ESR1 amplification remain to be conclusively addressed:(1) The extent to which abundant amounts of messenger RNA can mimic amplification in standard fluorescence in situ hybridization assays in the analysis of strongly expressed genes like ESR1,and(2) the clinical relevance of ESR1 amplification:Such relevance is strongly disputed,with data showing predictive value for response as well as for resistance of the cancer to anti-estrogen therapies,or for subsequent development of cancers in the case of precursor lesions that display amplification of ESR1.This review provides a comprehensive summary of the various views on ESR1 amplification,and highlights explanations for the contradictions and conflicting data that could inform future ESR1 research.

Use of adenovirus vector expressing the mouse full estrogen receptor alpha gene to infect mouse primary neurons

Estrogen plays important regulatory and protective roles in the central nervous system through estrogen receptor a mediation. Previous studies applied eukaryotic expression and lentiviral vectors carrying estrogen receptor a to cladfy the underlying mechanisms. In the present study, an adenovirus vector expressing the mouse full estrogen receptor a gene was constructed to identify biological characteristics of estrogen receptor a recombinant adenovirus infecting nerve cells. Primary cultured mouse nerve cells were first infected with estrogen receptor a recombinant adenovirus at various multiplicities of infection, followed by 100 multiplicity of infection. Results showed overexpression of estrogen receptor α mRNA and protein in the infected nerve cells. Estrogen receptor a recombinant adenovirus at 100 multiplicity of infection successfully infected neurons and upregulated estrogen receptor a mRNA and protein expression.

Expression of estrogen receptor alpha in preimplantation mice embryos

Objective:To study the expression of estrogen receptor alpha(ERα) in preimplantation mice embryos.Methods:Mice zygotes were collected from superovulated Kunming mice and cultured in vitro.Embryos at different developmental stages were collected at 0,24,36,48,72 and 96hours after cultivation.The expression of ERα in early mice embryos was detected by reverse transcription-PCR(RT-PCR) and immunocytochemistry.Results:The expression of ERα mRNA was detected in all of the examined embryonic stages.The relative amount of ERα mRNA showed no significant difference between 1-cell stage embryos and 4-cell stage embryos(P>0.05).However,the relative level of ERα mRNA significantly decreased(P<0.05) at 2-cell stage and was the lowest at this stage.Over 2-cell stage,the ERα mRNA relative level would increase and achieve the peak level at blastocyst stage.The location of immunocytochemistry showed that ERα immunopositive cells could be firstly detected at 8-cell stage,after which they are consistently detected until blastocyst stage.In addition,the intensity of ERα positive staining was higher at blastocyst stage compared with that at 8-cell stage and morula stage.Conclusion:ERα is expressed in preimplantation mice embryos in a temporal and spatial pattern and may be involved in regulating the development of early mice embryos,which probably plays crucial roles in early embryonic development.

Expression of estrogen receptor alpha,nerve growth factor,interleukin-2,and androgen receptor in the cerebellum of ovariectomized rats following soybean isoflavone treatment

BACKGROUND： Studies have shown that estrogen receptor alpha （ERα）, nerve growth factor （NGF）, interleukin-2 （IL-2）, and androgen receptor （AR） expression in the cerebellum decreases when estrogen levels decrease in vivo. Soybean isoflavone, a type of non-steroid estrogen with similar molecular structure and function to estradiol, exhibits estrogen-like characteristics. OBJECTIVE： To investigate the effects of various doses of soybean isoflavone on expression of ERa, NGF, IL-2, and AR in the cerebellum of ovariectomized rat, and to determine whether there is a dose-dependent effect.DESIGN, TIME AND SETTING： Controlled trial at the cellular and molecular level. The study was performed at the Experimental Animal Engineering Center, College of Veterinary Medicine, Sichuan Agricultural University from July 2006 to May 2008. MATERIALS： Soybean isoflavone, comprised of daidzin, genistein and isoflavone, was provided by Taiyuan Yuantai Biochemical Industry, China. The ERα, NGF, IL-2, and AR in situ hybridization kit, rabbit anti-rat ERa, NGF, IL-2, and AR monoclonal antibodies, and SABC kit were purchased from Wuhan Boster Biological Technology, China. METHODS： A total of 50 female, Sprague Dawley rats, aged 3 months, were randomly assigned to 5 groups, with 10 animals in each group. With the exception of the sham-operation group （abdominal cavity opening alone）, all rats underwent bilateral ovariectomy. At 14 days after surgery, rats in the high-, middle-, and low-dose soybean isoflavone groups were subcutaneously injected with 1.5, 1.0, and 0.5 mg/kg soybean isoflavone, respectively, every 2 days for 6 consecutive weeks. Rats in the sham-operation and ovariectomized groups were subcutaneously injected with absolute alcohol （0.5 mL/kg）. MAIN OUTCOME MEASURES： Expression levels and distribution of ERα, NGF, IL-2, and AR in the cerebellum were detected by immunohistochemistry and in situ hybridization. RESULTS： Compared with the sham-operation group, immunoreactive products and hybridization signals of ERa, NGF, IL-2, and AR were significantly decreased in the cerebellar cortex and nuclei of ovariectomized rats （P 〈 0.05 or P 〈 0.01）, but increased following soybean isoflavone treatment. In particular, levels of the high-dose soybean isoflavone group were almost restored to levels of the sham-operation group （P 〉 0.05）. The immunoreactive products were primarily located in the cytoplasm and neurites, and rarely in the cell membrane and nuclei. However, the hybridization signals were predominantly located in the nuclei, but rarely in the cytoplasm, cell membrane, or neurites. CONCLUSION： Soybean isoflavone upregulated ERα, NGF, IL-2, and AR protein and gene expression in a dose-dependent manner, and played an important role in sustaining and protecting structure and function of cerebellar neurons. Moreover, the similarity of expression patterns of these molecules indicated that they were mutually interactive during the regulation of soybean isoflavone to the cerebellum.

Clinicopathological Features and Long-Term Prognostic Role of Human Epidermal Growth Factor Receptor-2 Low Expression in Chinese Patients with Early Breast Cancer:A Single-Institution Study

Objective This study aimed to comprehensively analyze and compare the clinicopathological features and prognosis of Chinese patients with human epidermal growth factor receptor 2(HER2)-low early breast cancer(BC)and HER2-IHC0 BC.Methods Patients diagnosed with HER2-negative BC(N=999)at our institution between January2011 and December 2015 formed our study population.Clinicopathological characteristics,association between estrogen receptor(ER)expression and HER2-low,and evolution of HER2 immunohistochemical(IHC)score were assessed.Kaplan-Meier method and log-rank test were used to compare the long-term survival outcomes(5-year follow-up)between the HER2-IHC0 and HER2-low groups.Results HER2-low BC group tended to demonstrate high expression of ER and more progesterone receptor(PgR)positivity than HER2-IHC0 BC group(P<0.001).The rate of HER2-low status increased with increasing ER expression levels(Mantel-Haenszelχ^(2)test,P<0.001,Pearson’s R=0.159,P<0.001).Survival analysis revealed a significantly longer overall survival(OS)in HER2-low BC group than in HER2-IHC0 group(P=0.007)in the whole cohort and the hormone receptor(HR)-negative group.There were no significant differences between the two groups in terms of disease-free survival(DFS).The discordance rate of HER2 IHC scores between primary and metastatic sites was 36.84%.Conclusion HER2-low BC may not be regarded as a unique BC group in this population-based study due to similar clinicopathological features and prognostic roles.

Estrogen Receptor Alpha 36 Gene Knockdown Promote the Expression of NF-κB in PC12 Cells

The nuclear transcription factors κB (NF-κB) is widely existing in various kinds of cell types in the nervous system and plays an important role in neuron apoptosis and neurodegenerative diseases. Estrogen receptor alpha 36 (ER-α36), is a novel variant of ERα (as known ER-α66) which can transduce both estrogenand antiestrogen-dependent activation of MAPK signal pathway and stimulate cell growth. Here, we aimed to detect the effect of ER-α36 gene silencing on the expression of NF-κB in normal cultured PC12 cells and to provide an experimental foundation for understanding the function of ER-α36 innerve cells. PC12 cells with ER-α36 expression knocked down by the shRNA method. Then Western blot and immunocytochemical staining were performed to detect the expression and translocation of NF-κB after transfection. The results showed that NF-κB expression was significantly higher comparing with the control group after transfection (P 0.01). Also, NF-κB subunit entered nuclear after transfection;Immunofluorescence staining and immunocytochemical staining of PC12 cells demonstrated that ER-α36 was expressed mainly on the plasma membrane and on the cell nucleus membrane. These data indicate that ER-α36 gene silencing can increase the expression of NF-κB and promote its nuclear translocation in PC12 cells.

Estrogen receptors in gastric cancer:Advances and perspectives

Worldwide, gastric cancer is one of the most common malignancies with high mortality. Various aspects of thedevelopment and progression of gastric cancer continue to be extensively investigated in order to further our understanding and provide more effective means for the prevention, diagnosis, and treatment of the disease. Estrogen receptors(ERs) are steroid hormone receptors that regulate cellular activities in many physiological and pathological processes in different tissues. There are two distinct forms of ERs, namely ERα and ERβ, with several alternative-splicing isoforms for each. They show distinct tissue distribution patterns and exert different biological functions. Dysregulation of ERs has been found to be associated closely with many diseases, including cancer. A number of studies have been conducted to investigate the role of ERs in gastric cancer, the possible mechanisms underlying these roles, and the clinical relevance of deregulated ERs in gastric cancer patients. To date, inconsistent associations of different ERs with gastric cancer have been reported. These inconsistencies may be caused by variations in in vitro cell models and clinical samples, including assay conditions and protocols with regard to different forms of ERs. Given the potential of the deregulated ERs as diagnostic/prognostic markers or therapeutic targets for gastric cancer, it will be important to identify/confirm the association of each ER isoform with gastric cancer, to determine the specific roles and interactions that these individual ER isoforms play under specific conditions in the development and/or progression of gastric cancer, and to elucidate precisely these mechanisms. In this review, we summarize the achievements from early ER studies in gastric cancer to the most up-to-date discoveries, with an effort to provide a comprehensive understanding of the role of ERs roles in gastric cancer and its possible mechanisms. Furthermore, we propose directions for future investigations.

Prognostic implications of estrogen receptor 1 and vascular endothelial growth factor A expression in primary gallbladder carcinoma

AIM: To investigate the prognostic significance of estrogen receptor 1(ER1) and vascular endothelial growth factor A(VEGF-A) expression in primary gallbladder carcinoma(GBC) to identify new prognostic markers for this malignancy.METHODS: Using immunohistochemistry, we investigated ER1 and VEGF-A expression in 78 GBC and 78 cholelithiasis(CS) tissues. The results were correlated with clinicopathological features. Univariate and multivariate analyses were performed to evaluate the relationship between ER1 and VEGF-A expression and patients' prognosis. Further Kaplan-Meier survival analysis was also performed. RESULTS: ER1 and VEGF-A expression was significantly higher in GBC compared with CS(47/78 vs 28/78, P < 0.05; 51/78 vs 33/78, P < 0.05). ER1 expression was correlated with gender(P < 0.05) and VEGF-A expression was correlated with tumor differentiation in GBC patients(P < 0.05). In univariate analysis, age and tumor node metastasis(TNM) stage were factors associated with GBC prognosis(P < 0.05). Although there was no statistical difference between the expression of ER1 or VEGF-A and overall survival, the high expression of ER1 combined with VEGF-A predicted a poor prognosis for GBC patients(16.30 ± 1.87 vs 24.97 ± 2.09, log-rank P < 0.05). In multivariate analysis, combined expression of ER1 and VEGF-A and TNM stage were independent prognostic factors for GBC patients(P < 0.05).CONCLUSION: Combined expression of ER1 and VEGF-A is a potential prognostic marker for GBC patients. Clinical detection of ER1 and VEGF-A in surgically resected GBC tissues would provide animportant reference for decision-making of postoperative treatment programs.

Estrogen, estrogen receptors, and hepatocellular carcinoma: Are we there yet?

A protective role of the sex steroid hormone estrogenin hepatocellular carcinoma(HCC) was suggested a few decades ago according to clinical data showing higher HCC morbidity and mortality among males. Several recent studies further confirmed the anti-cancer effects of estrogen in the liver. However, it remains to be identified how to exploit estrogen signalling within clinical settings for HCC treatment. There are several unresolved issues related to the estrogen pathway in liver cells. The main problems include the absence of a clear understanding of which estrogen receptor(ER) isoform is predominantly expressed in normal and malignant liver cells, the ER isoform expression difference between males and females, and which ER isoform should be targeted when designing HCC therapy. Some of those questions were recently addressed by Iyer and coauthors. The current editorial review critically analyses the study by Iyer et al(WJG, 2017) that investigated the expression of ER subtypes in liver samples collected from patients with a healthy liver, hepatitis C virus cirrhosis, and HCC. ER presence was evaluated in association with gender, intracellular localization, inflammation marker NF-kB, and proliferation-related effector cyclin D1. The study limitations and advantages are discussed in light of recent advances in the HCC and estrogen signalling areas.

The Relationship of CyclinD1 and Estrogen Receptor Expression in the Process of Proliferation and Metastasis in Breast Neoplasm

The role of CyclinD1 and estrogen receptor (ER) in the process of proliferation and metastasis of breast neoplasm and their relationship were studied. The expression levels of CyclinD1 and ER in the tissue samples were detected by using flow cytometry and L SAB immunohistochemistry staining, respectively. The results showed that CyclinD1 and ER expression levels in breast cancer were significantly higher than in benign breast neoplasm (P<0.05). The CyclinD1 expression levels in stage I was much lower than in stages Ⅱ, Ⅲ, Ⅳ (P<0.05). The positive rate of ER was not related with tumor size, lymph node metastasis and TNM stage (P>0.05), but the CyclinD1 expression level in ER (+) group was significantly higher than in ER (-) group (P<0.05). It was concluded that CyclinD1 expression level might be obviously related with the proliferation and metastasis of breast neoplasm and ER.

17β-Estradiol Regulates Cultured Immature Boar Sertoli Cell Proliferation via the cAMP-ERK1/2 Pathway and the Estrogen Receptor β

Estrogen plays an important role in regulating Sertoli cell number in the testis. The objective of the study was to identify whether 17β-estradiol affected the proliferation of cultured, immature boar Sertoli cells via the estrogen receptor β （ERβ） and the cAMP-extracellular signal-regulated kinase （ERK1/2） pathway. Low levels （10-10-10-8 mol L-1） of 17β-estradiol increased cell number, but high levels （10-7-10-6 mol L-1） decreased it （P〈0.05）. Sertoli cell number began to recover for an additional 24 h in the medium without 17β-estradiol （10-6 mol L-l） （P〉0.05）. The effects of 17β-estradiol （10-9 mol L-1） peaked at the first 24 h （P〈0.05）. 17β-estradiol activated ERK1/2 from 5 min to 24 h, but the activiy of ERK1/2 began to decrease after 4 h. Both PD98059 and U0126, two ERK inhibitors, blocked cell division （P〈0.05）. 17β-estradiol （10-10-10-6 mol L-1） dose-dependently increased cAMP production （P 〈 0.05）, and both 17β-estradiol （10-9 mol L-1） and forskolin, which increases cAMP levels, induced cell proliferation and activated ERK1/2 （P〈 0.05）. Rp-cAMP, an antagonist of cAMP, blocked this 17β-estradiol activity （P〈 0.05）. Two estrogen receptor antagonists, ICI 182780 and ERβ antagonist （ERβAnt）, reduced Sertoli cell number, cAMP production and ERK1/2 activation （P〈 0.05）, but ERaAnt did not （P〉 0.05）. Therefore, 17β- estradiol mainly promotes pig Sertoli cell proliferation via ERβ to induce cAMP production and ERK activation to promote cell proliferation.

Role of estrogen receptor β selective agonist in ameliorating portal hypertension in rats with CCl4-induced liver cirrhosis

AIM: To investigate the role of diarylpropionitrile(DPN), a selective agonist of estrogen receptor β(ERβ), in liver cirrhosis with portal hypertension(PHT) and isolated hepatic stellate cells(HSCs).METHODS: Female Sprague-Dawley rats were ovariectomized(OVX), and liver cirrhosis with PHT was induced by CCl4 injection. DPN and PHTPP, the selective ERβ agonist and antagonist, were used as drug interventions. Liver fibrosis was assessed by hematoxylin and eosin(HE) and Masson's trichrome staining and by analyzing smooth muscle actin expression. Hemodynamic parameters were determined in vivo using colored microspheres technique. Protein expression and phosphorylation were determined by immunohistochemical staining and Western blot analysis. Messenger RNA levels were analyzed by quantitative real-time polymerase chain reaction(q RT-PCR). Collagengel contraction assay was performed using gel lattices containing HSCs treated with DPN, PHTPP, or Y-27632 prior to ET-1 addition. RESULTS: Treatment with DPN in vivo greatly lowered portal pressure and improved hemodynamic parameters without affecting mean arterial pressure, which was associated with the attenuation of liver fibrosis and intrahepatic vascular resistance(IHVR). In CCl4-treated rat livers, DPN significantly decreased the expression of Rho A and ROCK Ⅱ, and even suppressed ROCK Ⅱ activity. Moreover, DPN remarkedly increased the levels of endothelial nitric oxide synthase(e NOS) and phosphorylated e NOS, and promoted the activities of protein kinase G(PKG), which is an NO effector in the liver. Furthermore, DPN reduced the contractility of activated HSCs in the 3-dimensional stress-relaxed collagen lattices, and decreased the ROCK Ⅱ activity in activated HSCs. Finally, in vivo /in vitro experiments demonstrated that MLC activity was inhibited by DPN.CONCLUSION: For OVX rats with liver cirrhosis, DPN suppressed liver Rho A/ROCK signal, facilitated NO/PKG pathways, and decreased IHVR, giving rise to reduced portal pressure. Therefore, DPN represents a relevant treatment choice against PHT in cirrhotic patients, especially postmenopausal women.

G protein-coupled estrogen receptor in colon function, immune regulation and carcinogenesis

Estrogens play important roles in the development and progression of multiple tumor types.Accumulating evidence points to the significance of estrogen action not only in tumors of hormonally regulated tissues such as the breast,endometrium and ovary,but also in the development of colorectal cancer(CRC).The effects of estrogens in physiological and pathophysiological conditions are mediated by the nuclear estrogen receptorsαandβ,as well as the membranebound G protein-coupled estrogen receptor(GPER).The roles of GPER in CRC development and progression,however,remain poorly understood.Studies on the functions of GPER in the colon have shown that this estrogen receptor regulates colonic motility as well as immune responses in CRC-associated diseases,such as Crohn’s disease and ulcerative colitis.GPER is also involved in cell cycle regulation,endoplasmic reticulum stress,proliferation,apoptosis,vascularization,cell migration,and the regulation of fatty acid and estrogen metabolism in CRC cells.Thus,multiple lines of evidence suggest that GPER may play an important role in colorectal carcinogenesis.In this review,we present the current state of knowledge regarding the contribution of GPER to colon function and CRC.

Current medical treatment of estrogen receptor-positive breast cancer

Approximately 80% of breast cancers(BC) are estrogen receptor(ER)-positive and thus endocrine therapy(ET) should be considered complementary to surgery in the majority of patients. The advantages of oophorectomy, adrenalectomy and hypophysectomy in women with advanced BC have been demonstrated many years ago, and currently ET consist of(1) ovarian function suppression(OFS), usually obtained using gonadotropinreleasing hormone agonists(Gn RHa);(2) selective estrogen receptor modulators or down-regulators(SERMs or SERDs); and(3) aromatase inhibitors(AIs), or a combination of two or more drugs. For patients aged less than 50 years and ER+ BC, there is no conclusive evidence that the combination of OFS and SERMs(i.e., tamoxifen) or chemotherapy is superior to OFS alone. Tamoxifen users exhibit a reduced risk of BC, both invasive and in situ, especially during the first 5 years of therapy, and extending the treatment to 10 years further reduced the risk of recurrences. SERDs(i.e., fulvestrant) are especially useful in the neoadjuvant treatment of advanced BC, alone or in combination with either cytotoxic agents or AIs. There are two types of AIs: type Ⅰ are permanent steroidal inhibitors of aromatase, while type Ⅱ are reversible nonsteroidal inhibitors. Several studies demonstrated the superiority of the third-generation AIs(i.e., anastrozole and letrozole) compared with tamoxifen, and adjuvant therapy with AIs reduces the recurrence risk especially in patients with advanced BC. Unfortunately, some cancers are or became ET-resistant, and thus other drugs have been suggested in combination with SERMs or AIs, including cyclin-dependent kinase 4/6 inhibitors(palbociclib) and mammalian target of rapamycin(m TOR) inhibitors, such as everolimus. Further studies are required to confirm their real usefulness.

The Relationship of the Expression of Estrogen Receptor in Cartilage Cell and Osteoarthritis Induced by Bilateral Ovariectomy in Guinea Pig

To investigate the estrogen receptor（ER） expression in cartilage cell in the development of oste0arthritis induced by bilateral ovariectomy in guinea pig and to find their relationship. 30 two-month-old female guinea pigs were randomly divided into two groups （n=15 each） ： sham operation （control）group and ovariectomized group （OVX）; Scanning electorne microscope （SEM） and transmission electron microscope （TEM） were obtained to analysis the cartilage degeneration of the hind limb knee joint after 6 and 12 weeks of ovariectomy. Dextran-Coated-Charcoal （DCC） was taken to quantitively detect the expression of ER. The serum levels of estrogen and gestone were detected by immune contest assay. The results showed that ER do exist in the cartilages of the guinea pigs, with higher expression in the control group than in OVX group at the same time point （P〈0. 05）. It was increased also at 12 th week after operation than that of preoperation. The blood serum levels of estrogen and gestone showed a similar tendency to the expression of ER. Joint cartilage degeneration detected by SEM and TEM could be found at 6 th week, but severe degenerative lesions at 12 th week in the OVX group compared with the control group （P〈0.01）. The data suggested that bilateral ovariectomy in guinea pig lead to severe os.teoarthritis which mighgt be related to the lower serum level of estrogen and the downregulation of the expression of ER in the cartilage also.

Estrogen Receptor α and β Expressions in Hypothalamus-pituitary-ovary Axis in Rats Exposed Lactationally to Soy Isoflavones and Bisphenol A

Objectives This paper aims to investigate the uterotrophic activities of lactational exposure to combination of soy isoflavones （SIF） and bisphenol A （BPA） and to examine estrogen receptor α （ERα） and estrogen receptor β （ERβ） expressions in hypothalamus-pituitary-ovary axis and uterus.Methods Maternal rats that were breeding about 8 litters were randomly divided into four groups with seven dams in each group.Dams in different treatment groups received corn oil （control）,150 mg/kg BW of SIF,150 mg/kg BW of BPA or combination of 150 mg/kg BW of SIF and 150 mg/kg BW of BPA,respectively,from postnatal day 5 to 11 （PND5-11） by gavage.On PND12 and PND70,10 female litters were killed and hypothalamus,pituitary,ovary and uterus were collected.ERα and ERβ expressions in these organs were detected with Western blotting assay.And vaginal opening time and estrus cycle were examined in animals fed for PND70.Results On PND12,the relative uterine weight of rats treated with ISF or BPA or their combination was significantly higher than that of untreated rats （P〈0.05）.But the relative uterine weight of rats in the co-exposure group was slightly lower than that in the group only exposed to SIF or BPA.On PND 70,however,the relative uterine weight in each treatment group was not statistically different from that in the control group （P〈0.05）.Vaginal opening time and estrus cycle in groups treated with SIF or BPA or their combination were similar to those in the control group （P〈0.05）.Exposure to SIF or BPA or their combination could up-regulate or down-regulate ERα and ERβ expressions in hypothalamus,pituitary,ovary and uterus on PND12 and PND70.These regulation patterns for ERα and ERβ were different in different organs at different time points.Conclusion Lactational exposure to ISF or BPA or their combination could induce uterotrophic responses in neonate rats,which disappeared in later life.But these data fail to suggest a possibility for synergic actions between SIF and BPA.It was also demonstrated that the uterotrophic effects of SIF and BPA exposure might,at least,involve modification of ERα or ERβ expressions in the hypothalamus-pituitary-ovary axis.