• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.10
• /
• pp.6081-6084
• /
• 2013

Objective: Both estrogen receptors, ER alpha ($ER{\alpha}$) and ER beta ($ER{\beta}$), are expressed in 50-70% of breast cancer cases. The role of $ER{\alpha}$ as a prognostic marker in breast cancer has been well established as its expression is negative correlated with tumor size and lymph node metastasis. $ER{\beta}$ is also a favorable prognostic predictor although this is less well documented than for $ER{\alpha}$. Materials and Methods: To explore whether ERs independently or together might influence clinical outcome in breast cancer, the correlation between the ERs with the clinicopathological features was analyzed in 84 patients. Results: $ER{\alpha}$ expression negatively correlated with tumor stage (r=-0.246, p=0.028) and tended to be negatively correlated with lymph node status (r=-0.156, p=0.168) and tumor size (r=-0.246, p=0.099). Also, $ER{\beta}$ was negatively correlated with nodal status (r=-0.243, p=0.028), as was coexpression of $ER{\alpha}$ and $ER{\beta}$ (p=0.043, OR=0.194, 95% CI= 0.040-0.953). Conclusion: Coexpression of ERs might serve as an indicator of good prognosis in breast cancer patients.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.6
• /
• pp.1107-1114
• /
• 2008

It is important to identify selective ligands for the estrogen receptor subtypes ER$\alpha$ or ER$\beta$ to evaluate them as pharmaceutical targets in breast cancer. To develop ER$\beta$-selective ligands as PET imaging agents, a series of aryl indazole estrogen analogues substituted at the C3 position with fluoroethyl and fluoropropyl groups were synthesized and evaluated for their relative binding affinities and selectivities for ER$\alpha$ vs ER$\beta$. The fluoroethylated indazole estrogen (FEIE, 1i) and fluoropropylated indazole estrogen (FPIE, 1h) showed 41- fold and 17-fold ER$\beta$/ER$\alpha$ selectivity, respectively. However, their binding affinities to ER$\alpha$ and ER$\beta$ were very low.

• YAKHAK HOEJI
• /
• v.54 no.2
• /
• pp.102-105
• /
• 2010

Our previous results showed that hypoxia inducible factor-1 (HIF-1) activated estrogen receptor (ER) in the absence of ligand. In this study, we have studied the effect ER overexpression on the activation of HIF-1. ER overexpression induced transcription activation of hypoxia response element driven luciferase and vascular endothelial growth factor. As a negative control, the effect of ER on androgen receptor response element was used. Our result indicate that the two ER$\alpha$ and HIF-1 signaling pathways shares part of the activation pathway.

• IMMUNE NETWORK
• /
• v.12 no.6
• /
• pp.253-260
• /
• 2012

${\alpha}$-Mangostin is a xanthon derivative contained in the fruit hull of mangosteen (Garcinia mangostana L.), and the administration of ${\alpha}$-Mangostin inhibited the growth of transplanted colon cancer, Her/CT26 cells which expressed Her-2/neu as tumor antigen. Although ${\alpha}$-Mangostin was reported to have inhibitory activity against sarco/endoplasmic reticulum $Ca^{2+}$ ATPase like thapsigargin, it showed different activity for autophagy regulation. In the current study, we found that ${\alpha}$-Mangostin induced autophagy activation in mouse intestinal epithelial cells, as GFP-LC3 transgenic mice were orally administered with 20 mg/kg of ${\alpha}$-Mangostin daily for three days. However, the activation of autophagy by ${\alpha}$-Mangostin did not significantly increase OVA-specific T cell proliferation. As we assessed ER stress by using XBP-1 reporter system and phosphorylation of $eIF2{\alpha}$, thapsigargin-induced ER stress was significantly reduced by ${\alpha}$-Mangostin. However, coadministration of thapsigargin with ${\alpha}$-Mangostin completely blocked the antitumor activity of ${\alpha}$-Mangostin, suggesting ER stress with autophagy blockade accelerated tumor growth in mouse colon cancer model. Thus the antitumor activity of ${\alpha}$-Mangostin can be ascribable to the autophagy activation rather than ER stress induction.

• Toxicological Research
• /
• v.20 no.3
• /
• pp.205-211
• /
• 2004

Concern that some chemicals in our environment may affect human health by disrupt-ing normal endocrine function has prompted a research on interactions of environmental contaminants with steroid hormone receptor. Toxaphene and chlordane are among the 12 persistent organic pollutants identified by the United Nations Environment Programme as requiring urgent attention. We compared the estrogenic activity of two organochlorine pesticides, toxaphene and chlordane, at estrogen receptor a (ER$\alpha$) and estrogen receptor $\beta$ (ER$\beta$). Human hepatoma cells (HepG2) were transiently transfected with rat ER$\alpha$ or ER$\beta$ plus an estrogen-responsive complement C3-luciferase (C3-Luc) reporter gene. After transfection, cells were treated with various concentrations of toxaphene and chlordane to investigate agonism or antagonism of these chemicals. Both toxaphene and chlordane were potent agonists in HepG2 cells for ER$\alpha$. In contrast, these chemicals had a minimal agonist activity with ER$\beta$ and almost abolished 17$\beta$-estradiol-induced ER$\beta$-mediated activity. Therefore, toxaphene and chlordane behaved as an ER$\alpha$ agonist and an ER$\beta$ antagonist with estrogen-responsive reporter plasmid C3-Luc, and exposure to these organochlorine pesticides could have a crictical effect on normal endocrine function.

• Molecules and Cells
• /
• v.26 no.5
• /
• pp.454-458
• /
• 2008

Sex steroid hormone receptors play a central role in modulating telomerase activity, especially in cancer cells. However, information on the regulation of steroid hormone receptors and their distinct functions on telomerase activity within the mesenchymal stem cell are largely unavailable due to low telomerase activity in the cell. In this study, the effects of estrogen ($E_2$) treatment and function of estrogen receptor alpha ($ER{\alpha}$) and estrogen receptor beta ($ER{\beta}$) on telomerase activity were investigated in human mesenchymal stem cells (hMSCs). Telomerase activity and mRNA expression of the catalytic subunit of telomerase (hTERT) were upregulated by treatment of the cells with $E_2$. The protein concentration of $ER{\alpha}$ was also increased by $E_2$ treatment, and enhancement of $ER{\alpha}$ accumulation in the nucleus was clearly detected with immunocytochemistry. When $ER{\alpha}$ expression was reduced by siRNA transfection into hMSCs, the effect of $E_2$ on the induction of hTERT expression and telomerase activity was diminished. In contrast, the transient overexpression of $ER{\alpha}$ increased the effect of $E_2$ on the expression of hTERT mRNA. These findings indicate that the activation of hTERT expression and telomerase activity by $E_2$ in hMSCs depends on $ER{\alpha}$, but not on $ER{\beta}$.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.11
• /
• pp.6761-6767
• /
• 2013

The nuclear receptor, peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$), is expressed in various cancer cells including breast, prostate, colorectal and cervical examples. An endogenous ligand of $PPAR{\gamma}$, 15-deoxy-${\Delta}^{12,14}$ prostaglandin $J_2$ (PGJ2), is emerging as a potent anticancer agent but the exact mechanism has not been fully elucidated, especially in breast cancer. The present study compared the anticancer effects of PGJ2 on estrogen receptor alpha ($ER{\alpha}$)-positive (MCF-7) and $ER{\alpha}$-negative (MDA-MB-231) human breast cancer cells. Based on the reported signalling cross-talk between $ER{\alpha}$ and $ER{\alpha}$, the effect of the $ER{\alpha}$ ligand, $17{\beta}$-estradiol (E2) on the anticancer activities of PGJ2 in both types of cells was also explored. Here we report that PGJ2 inhibited proliferation of both MCF-7 and MDA-MB-231 cells by inducing apoptotic cell death with active involvement of mitochondria. The presence of E2 potentiated PGJ2-induced apoptosis in MCF-7, but not in MDA-MB-231 cells. The $ER{\alpha}$ antagonist, GW9662, failed to block PGJ2-induced activities but potentiated its effects in MCF-7 cells, instead. Interestingly, GW9662 also proved capable of inducing apoptotic cell death. It can be concluded that E2 enhances $ER{\alpha}$-independent anticancer effects of PGJ2 in the presence of its receptor.

• Molecules and Cells
• /
• v.41 no.11
• /
• pp.964-970
• /
• 2018

Atherosclerosis preferentially involves in prone area of low and disturbed blood flow while steady and high levels of laminar blood flow are relatively protected from atherosclerosis. Disturbed flow induces endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). ER stress is caused under stress that disturbs the processing and folding of proteins resulting in the accumulation of misfolded proteins in the ER and activation of the UPR. Prolonged or severe UPR leads to activate apoptotic signaling. Recent studies have indicated that disturbed flow significantly up-regulated $p-ATF6{\alpha}$, $p-IRE1{\alpha}$, and its target spliced XBP-1. However, the role of laminar flow in ER stress-mediated endothelial apoptosis has not been reported yet. The present study thus investigated the role of laminar flow in ER stress-dependent endothelial cell death. The results demonstrated that laminar flow protects ER stress-induced cleavage forms of PARP-1 and caspase-3. Also, laminar flow inhibits ER stress-induced $p-eIF2{\alpha}$, ATF4, CHOP, spliced XBP-1, ATF6 and JNK pathway; these effects are abrogated by pharmacological inhibition of PI3K with wortmannin. Finally, nitric oxide affects thapsigargin-induced cell death in response to laminar flow but not UPR. Taken together, these findings indicate that laminar flow inhibits UPR and ER stress-induced endothelial cell death via PI3K/Akt pathway.

• BMB Reports
• /
• v.44 no.7
• /
• pp.452-457
• /
• 2011

The Egr-1 is an immediate early response gene encoding a transcription factor that functions in the regulation of cell growth, differentiation, and apoptosis. Estrogen has diverse physiological effects, including cellular proliferation and neuroprotection against brain injury. There are two types of estrogen receptors (ERs), $ER{\alpha}$ and $ER{\beta}$. $ER{\alpha}$-induced Egr-1 expression has been extensively studied; however, the role of $ER{\beta}$ is yet not known. In the present study, we investigated whether or not $ER{\beta}$ induces Egr-1 expression in C6 rat glioma cells, which express $ER{\beta}$ but not $ER{\alpha}$. Our results show that $ER{\beta}$ promoted up-regulation of Egr-1 expression via a non-genomic mechanism involving the Raf/MEK1/Erk/Elk-1 signaling cascade.

• Journal of Life Science
• /
• v.19 no.5
• /
• pp.593-597
• /
• 2009

The uterus plays a critical role in pregnancy and steroid hormones, and both estrogen (E2) and progesterone (P4) especially play important roles in the cross-talk between embryos and uterus to support the pregnancy. E2 stimulates uterine growth during early pregnancy to prepare for implantation of embryos. This cross-talk during the implantation period involves hormones (E2 and P4) and growth factors, including insulin-like growth factor-I (IGF-I). In the uterus of a pregnant pig, the action of E2 is mediated by estrogen receptor-${\beta}$ (ER-${\beta}$). The expression of ER-a was much higher in early pregnancy than in mid- and late- pregnancy, suggesting E2 secretion from embryos enhances transcription of ER-a during early pregnancy. In order to prove whether IGF-I is an E2 target gene, quantitative real-time PCR was performed on ovariectomized murine uterus with E2 and/or P4 treatment(s). Increased IGF-I mRNA expression was observed with E2 treatment, however, it was not significantly induced by P4 treatment, which clearly demonstrates that, in mice, E2 depends on the activation of uterine IGF-I gene expression. The expression of IGF-I in the uterus of pigs was much higher in early pregnancy than in mid- and late- pregnancy and these data exhibited the same expression pattern with the ER-${\beta}$ gene expression in the uterus. It suggests that a positive co-relationship between IGF-I and ER-${\beta}$ expression exists in the uterus, and that both gene expressions of IGF-I and ER-${\beta}$ are regulated by E2. It further suggests that uterine the IGF-I gene expression might be initiated by E2 secreted from embryos to increase ER-${\beta}$ gene expression, and that this increased ER-${\beta}$ further stimulates the expression of IGF-I in the uterus during early pregnancy.