The localization of estrogen (E2) has been clearly shown in hippocampus, called local hippocampal E2. It enhanced neuronal synaptic plasticity and protected neuron form cerebral ischemia, similar to those effects of exogenous E2. However, the interactive function of hippocampal and exogenous E2 on synaptic plasticity activation and neuroprotection is still elusive. By using hippocampal H19-7 cells, we demonstrated the local hippocampal E2 that totally suppressed by aromatase inhibitor anastrozole. Anastrozole also suppressed estrogen receptor (ER)beta, but not ERalpha, expression. Specific agonist of ERalpha (PPT) and ERbeta (DPN) restored ERbeta expression in anastrozole-treated cells. In combinatorial treatment with anastrozole and phosphoinositide kinase-3 (PI-3K) signaling inhibitor wortmannin, PPT could not improve hippocampal ERbeta expression. On the other hand, DPN induced basal ERbeta translocalization into nucleus of anastrozole-treated cells. Exogenous E2 increased synaptic plasticity markers expression in H19-7 cells. However, exogenous E2 could not enhance synaptic plasticity in anastrozole-treated group. Exogenous E2 also increased cell viability and B-cell lymphoma 2 (Bcl2) expression in H2O2-treated cells. In combined treatment of anastrozole and H2O2, exogenous E2 failed to enhance cell viability and Bcl2 expression in hippocampal H19-7 cells. Our results provided the evidence of the priming role of local hippocampal E2 on exogenous E2-enhanced synaptic plasticity and viability of hippocampal neurons.
Androstadienes/pharmacology ; Animals ; Aromatase Inhibitors/pharmacology ; Cell Line ; Cell Survival/drug effects ; Estrogen Receptor alpha/agonists/metabolism ; Estrogen Receptor beta/agonists/metabolism ; Estrogens/*metabolism/pharmacology ; Hippocampus/cytology/*metabolism ; Hydrogen Peroxide/pharmacology ; Nervous System/*drug effects ; Neuronal Plasticity/*drug effects ; *Neuroprotective Agents ; Nitriles/pharmacology ; Phosphatidylinositol 3-Kinase/antagonists & inhibitors ; Proto-Oncogene Proteins c-bcl-2/biosynthesis ; Rats ; Triazoles/pharmacology

OBJECTIVETo study the effects of exogenous ER beta on the growth of breast cancer MCF-7 cells under different treatment.

METHODSAn eukaryotic expression vector containing 1.6 kb of human entire coding sequence of ER beta (pCDNA3-ER beta) was transfected into human breast cancer MCF-7 cells using lipofectamine 2000. The biological activity of ER beta was detected with the luciferase reporter containing estrogen responsive element (ERE) and the expression of ER beta protein by Western blot. The growth properties of MCF-7, pCDNA 3-transfected MCF-7 and pCDNA 3-ER beta-transfected MCF-7 cells under different treatment, including E2 (17beta-estradiol) and 4-OHT (4-hydroxytamoxifen), were observed.

RESULTSA stronger activation of the reporter by ER beta in the presence of E2 was observed in the pCDNA 3-ER beta-transfected MCF-7 cells than in the pCDNA 3-transfected MCF-7 and in MCF-7 cells. Western blot analysis showed that the protein level of ER beta in the pCDNA 3-ER beta-transfected MCF-7 cells was markedly increased. Exogenous ER beta expression did not change the growth properties and the morphology of MCF-7 cells under normal condition. The pCDNA 3-ER beta-transfected MCF-7 cells proliferated at the same rate as naive cells in the presence of 4-OHT, whereas a strong inhibition of the proliferation of the pCDNA 3-ER beta-transfected MCF-7 cells in the presence of E2 was observed.

CONCLUSIONExogenous ER beta expression does not increase the resistance to 4-OHT, and a strong inhibition of the proliferation may occur in the presence of E2.

Breast Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Estradiol ; pharmacology ; Estrogen Antagonists ; pharmacology ; Estrogen Receptor beta ; genetics ; metabolism ; Female ; Humans ; Tamoxifen ; analogs & derivatives ; pharmacology ; Transfection

Carnosol has been proved to have anti-breast cancer effect in previous research. But its ER subtype's specific regulation and mediation mechanisms remain unclear. The aim of this study is to observe the effect of carnosol on cell proliferation and its estrogen receptor α and β's specific regulation and mediation mechanisms with ER positive breast cancer T47D cell. With estrogen receptor α and β antagonists MPP and PHTPP as tools, the MTT cell proliferation assay was performed to observe the effect of carnosol on T47D cell proliferation. The changes in the T47D cell proliferation cycle were detected by flow cytometry. The effect of carnosol on ERα and ERβ expressions of T47D cells was measured by Western blot. The findings showed that 1 x 10(-5)-1 x 10(-7) mol x L(-1) carnosol could significantly inhibit the T47D cell proliferation, which could be enhanced by MPP or weakened by PHTPP. Meanwhile, 1 x 10(-5) mol x L(-1) or 1 x 10(-6) mol x L(-1) carnosol could significantly increase ERα and ERβ expressions of T47D cells, and remarkably increase ERα/ERβ ratio. The results showed that carnosol showed the inhibitory effect on the proliferation of ER positive breast cancer cells through target cell ER, especially ERβ pathway. In the meantime, carnosol could regulate expressions and proportions of target cell ER subtype ERα and ERβ.
Blotting, Western ; Breast Neoplasms ; metabolism ; pathology ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Diterpenes, Abietane ; chemistry ; pharmacology ; Dose-Response Relationship, Drug ; Estrogen Receptor Modulators ; pharmacology ; Estrogen Receptor alpha ; antagonists & inhibitors ; metabolism ; Estrogen Receptor beta ; antagonists & inhibitors ; metabolism ; Female ; Flow Cytometry ; Humans ; Molecular Structure ; Pyrazoles ; pharmacology ; Pyrimidines ; pharmacology

OBJECTIVETo determine the effects of raloxifene hydrochloride (RLX) on bone mineral density (BMD), bone metabolism markers and serum lipids in healthy postmenopausal women in Beijing.

METHODSA multicenter, randomized, double-blind, placebo-controlled study was conducted in a total of 204 healthy postmenopausal women (age 59.5 +/- 5.0 years and weight 62.8 +/- 8.7 kg) treated with either RLX 60 mg (n = 102) or placebo (n = 102) daily for 12 months. BMD, serum lipids, and bone markers were measured before and after drug administration.

RESULTSCompared with placebo, RLX produced a significant increase in both total lumbar spine and total hip BMD. For the lumbar spine, percentage increase in total BMD was 2.3% with RLX compared with a decrease of 0.1% with placebo (P < 0.001). Corresponding values for total hip BMD were a 2.5% increase for RLX and a 1.1% increase for placebo (P = 0.011). For biochemical markers of bone metabolism, serum osteocalcin and C-telopeptide, percentage decreases were 27.65% and 24.02% in RLX-treated subjects. Corresponding values in placebo were a 10.64% decrease and a 15.75% increase (RLX compared with placebo, both P < 0.001). For total cholesterol and low-density lipoprotein cholesterol levels, percentage decreases were 6.44% and 34.58% in the RLX-treated group. Corresponding values in placebo-treated patients were a 1.44% increase and a 19.07% decrease (RLX compared with placebo, both P < 0.001). No differences were found for high-density lipoprotein cholesterol or triglyceride levels between the two groups. Only 5 subjects discontinued early owing to an adverse event (3 in the RLX group and 2 in the placebo group).

CONCLUSIONSThis study confirms that RLX exerts positive effects on the skeleton, increasing BMD and decreasing biochemical markers of bone metabolism, and has a positive effect on the overall serum lipid profile in postmenopausal women in China.

Aged ; Biomarkers ; blood ; Bone Density ; drug effects ; Bone and Bones ; metabolism ; China ; Estrogen Antagonists ; pharmacology ; Female ; Humans ; Lipids ; blood ; Middle Aged ; Postmenopause ; physiology ; Raloxifene Hydrochloride ; pharmacology ; Selective Estrogen Receptor Modulators ; pharmacology

ER-α36 is a novel 36-kDa variant of ER-α. A large of evidence demonstrated that ER-α36 responded to membrane-initiated estrogen signaling pathways which were involved in the physiological and pathological process in many kinds of cells. In this study, knock-down of ER-α36 expression in pheochromocytoma (PC12) cells (named as PC12-36L cells) by using the shRNA method was used to evaluate the relationship between ER-α36 and Akt in neurons under glucose deprivation. The effect of ER-α36 on outgrowth of PC12 cells, as well as the neuroprotective effect of ER-α36 on injured PC12 cells exposed to glucose deprivation was observed by using MTT assay, Western blot and Annexin V/PI staining et al. The results showed that, (1) Glucose deprivation induced by MEM treatment for 6 h reduced survival rate and increased apoptotic rate in PC12 cells significantly compared to control group (P < 0.01); and it produced a decrease in the expression of Glut-4 protein (P < 0.01); (2) The expression level of ER-α36 was decreased significantly at 3 h of glucose deprivation, and then increased, while phosphorylation of Akt participated in the glucose deprivation was increased at first and then reduced; LY294002 (PI3K inhibitor) contributed to decreased expression of ER-α36, and suppressed the activation of Akt; (3) The rate of apoptosis was significantly increased in PC12-36L cells after glucose deprivation compared with that in wild type PC12 cells (P < 0.01). Furthermore, phosphorylation of Akt was decreased and Caspase-3 was increased by glucose deprivation in PC12-36L cells compared with those in wild type PC12 cells. The study reveals that phosphorylation of Akt is associated with ER-α36 in PC12 cells exposed to glucose deprivation, and both are involved in the regulation of stress responses.
Animals ; Apoptosis ; Caspase 3 ; metabolism ; Chromones ; pharmacology ; Culture Media ; chemistry ; Estrogen Receptor alpha ; metabolism ; Glucose ; chemistry ; Morpholines ; pharmacology ; PC12 Cells ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Signal Transduction

Estrogen receptor beta (ERβ) is one of the two key receptors (ERα, ERβ) that facilitate biological actions of 17β-estradiol (E2). ERβ is widely expressed in many tissues, and its expression is reduced or lost during progression of many tumors. ERβ facilitates estrogen signaling by both genomic (classical and non-classical) and extra-nuclear signaling. Emerging evidence suggests that ERβ functions as a tissue-specific tumor suppressor with anti-proliferative actions. Recent studies have identified a number of naturally available selective ERβ agonists. Targeting ERβ using its naturally available ligands is an attractive approach for treating and preventing cancers. This review presents the beneficial actions of ERβ signaling and clinical utility of several natural ERβ ligands as potential cancer therapy.
Antineoplastic Agents, Phytogenic ; pharmacology ; therapeutic use ; Equol ; pharmacology ; therapeutic use ; Estrogen Receptor beta ; antagonists & inhibitors ; metabolism ; Flavanones ; pharmacology ; therapeutic use ; Genistein ; pharmacology ; therapeutic use ; Glycyrrhiza ; chemistry ; Humans ; Ligands ; Neoplasms ; drug therapy ; metabolism ; Phytotherapy ; Plant Extracts ; pharmacology ; therapeutic use ; Soybeans ; chemistry

Estrogen has anti-colorectal cancer effects which are thought to be mediated by mismatch repair gene (MMR) activity. Estrogen receptor (ER) expression is associated with microRNA (miRNA) expression in ER-positive tumors. However, studies of direct link between estrogen (especially estradiol E2), miRNA expression, and MMR in colorectal cancer (CRC) have not been done. In this study, we first evaluated the effects of estradiol (E2) and its antagonist ICI182,780 on the expression of miRNAs (miR-31, miR-155 and miR-135b) using COLO205, SW480 and MCF-7 cell lines, followed by examining the association of tissue miRNA expression and serum E2 levels using samples collected from 18 colorectal cancer patients. E2 inhibited the expressions of miRNAs in COLO205 cells, which could be reversed by E2 antagonist ICI 182.780. The expression of miR-135b was inversely correlated with serum E2 level and ER-beta mRNA expression in CRC patients' cancer tissues. There were significant correlations between serum E2 level and expression of ER-beta, miR-135b, and MMR in colon cancer tissue. This study suggests that the effects of estrogen on MMR function may be related to regulating miRNA expression via ER-beta, which may be the basis for the anti-cancer effect in colorectal cells.
Adaptor Proteins, Signal Transducing/genetics/metabolism ; Adult ; Aged ; Cell Line, Tumor ; Colorectal Neoplasms/*genetics/metabolism ; DNA Mismatch Repair/*genetics ; Estradiol/analogs & derivatives/blood/*pharmacology ; Estrogen Antagonists/pharmacology ; Estrogen Receptor beta/genetics/*metabolism ; Female ; *Gene Expression Regulation, Neoplastic ; Humans ; Male ; MicroRNAs/genetics/*metabolism ; Middle Aged ; MutS Homolog 2 Protein/genetics/metabolism ; Nuclear Proteins/genetics/metabolism ; RNA, Messenger/biosynthesis

Peroxisome proliferator activated receptor (PPAR) gamma coactivator-1alpha (PGC-1alpha) may be implicated in cholesterol metabolism since PGC-1alpha co-activates estrogen receptor alpha (ERalpha) transactivity and estrogen/ERalpha induces the transcription of LDL receptor (LDLR). Here, we show that overexpression of PGC-1alpha in HepG2 cells represses the gene expression of LDLR and does not affect the ERalpha-induced LDLR expression. PGC-1alpha suppressed the LDLR promoter-luciferase (pLR1563-luc) activity regardless of cholesterol or functional sterol-regulatory element-1. Serial deletions of the LDLR promoter revealed that the inhibition by PGC-1alpha required the LDLR promoter regions between -650 bp and -974 bp. Phosphorylation of PGC-1alpha may not affect the suppression of LDLR expression because treatment of SB202190, a p38 MAP kinase inhibitor, did not reverse the LDLR down-regulation by PGC-1alpha. This may be the first report showing the repressive function of PGC-1alpha on gene expression. PGC-1alpha might be a novel modulator of LDLR gene expression in a sterol-independent manner, and implicated in atherogenesis.
Base Sequence ; Cell Line, Tumor ; Cholesterol/metabolism ; Estrogen Receptor alpha/metabolism ; Gene Expression Regulation ; Heat-Shock Proteins/*genetics/*metabolism ; Humans ; Molecular Sequence Data ; Promoter Regions, Genetic ; RNA, Messenger/genetics ; Receptors, LDL/*genetics/*metabolism ; Sterol Regulatory Element Binding Protein 2/metabolism ; Transcription Factors/*genetics/*metabolism ; p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors

The aim of the present study was to investigate the involvements of insulin-like growth factor-1 (IGF-1) and estrogen receptor α (ERα) in the inhibitory effect of wogonin on the breast adenocarcinoma growth. Moreover, the effect of wogonin on the angiogenesis of chick chorioallantoic membrane (CAM) was also investigated. MCF-7 cells (human breast adenocarcinoma cell line) were subjected to several drugs, including IGF-1, wogonin and ER inhibitor ICI182780, alone or in combination. MTT assay was used to detect breast cancer proliferation. Western blot was used to analyze ERα and p-Akt expression levels. CAM models prepared from 6-day chicken eggs were employed to evaluate angiogenesis inhibition. The results showed wogonin and ICI182780 both exhibited a potent ability to blunt IGF-1-stimulated MCF-7 cell growth. Either of wogonin and ICI182780 significantly inhibited ERα and p-Akt expressions in IGF-1-treated cells. The inhibitory effect of wogonin showed no difference from that of ICI182780 on IGF-1-stimulated expressions of ERα and p-Akt. Meanwhile, wogonin at different concentrations showed significant inhibitory effect on CAM angiogenesis. These results suggest the inhibitory effect of wogonin on breast adenocarcinoma growth via inhibiting IGF-1-mediated PI3K-Akt pathway and regulating ERα expression. Furthermore, wogonin has a strong anti-angiogenic effect on CAM model.
Adenocarcinoma ; metabolism ; pathology ; Angiogenesis Inhibitors ; pharmacology ; Animals ; Breast Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Chick Embryo ; Chorioallantoic Membrane ; blood supply ; Estrogen Receptor alpha ; genetics ; metabolism ; Female ; Flavanones ; pharmacology ; Humans ; Insulin-Like Growth Factor I ; antagonists & inhibitors ; pharmacology ; Scutellaria ; chemistry

OBJECTIVETo investigate the expression of ER alpha in chemically induced, ER alpha-negative human breast cancer MDA-MB-435 cells and its restoration of the responsiveness to endocrine therapy.

METHODSMDA-MB-435 cells were treated with HDAC inhibitor trichostatin A(TSA)and DNMT1 inhibitor 5-AZA-CdR (AZA). The mRNA level of ER alpha, PR and PS2 in treated MDA-MB-435 cells was detected by RT-PCR. The WST-8 (water-soluble tetrazolium salt-8) method was used to analyze the proliferation rate of the cells. Xenograft in female nude mice was used to further explore the change of proliferation rate of treated MDA-MB-435 cells in vivo.

RESULTSAfter treatment with AZA and TSA, mRNA expression of ER alpha, PR and pS2 was up-regulated in MDA-MB-435 cells. The mRNA level of ER alpha was the hightest when MDA-MB-435 cells were treated with 2.5 micromol/L AZA and 100 ng/ml TSA. The treated MDA-MB-435 cells showed different proliferation rate in various media containing different concentration of estrodial. The MDA-MB-435 cells showed down-regulated proliferation rate after treatment with the combination of 2.5 micromol/L AZA and 100 ng/ml TSA, and 4-OH tamoxifen could suppress the growth rate of the induced MD-MBA-435 cells but not the untreated cells. The treated MDA-MB-435 cells showed slower proliferation rate than that of untreated cells in vivo (P <0. 01), and the proliferation rate of the treated MDA-MB-435 cells became lower when the nude mice were deprived of estrogen by castration (P <0. 01).

CONCLUSIONAfter treatment with TSA and AZA, ER alpha-negative MDA-MB-435 cells can express functional ER alpha and regain responsiveness to estrogen both in vitro and in vivo. HDAC inhibitor and DNMT1 inhibitor may play an important role in restoration of sensitivity of ER alpha-negative breast cancers to endocrine therapy.

Animals ; Azacitidine ; analogs & derivatives ; pharmacology ; Breast Neoplasms ; genetics ; pathology ; prevention & control ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; DNA Modification Methylases ; antagonists & inhibitors ; Enzyme Inhibitors ; pharmacology ; Estrogen Receptor alpha ; genetics ; Female ; Gene Expression Regulation, Neoplastic ; drug effects ; Histone Deacetylase Inhibitors ; Humans ; Hydroxamic Acids ; pharmacology ; Mammary Neoplasms, Experimental ; genetics ; pathology ; prevention & control ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Ovariectomy ; RNA, Messenger ; biosynthesis ; genetics ; Receptors, Progesterone ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Trefoil Factor-1 ; Tumor Suppressor Proteins ; genetics ; Xenograft Model Antitumor Assays