• Asian Pacific Journal of Cancer Prevention
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• 제15권20호
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• pp.8789-8791
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• 2014

Estrogen receptor alpha ($ER{\alpha}$) is one of the major sub-types of estrogen receptors. $ER{\alpha}$ plays an important role in cellular proliferation and differentiation, chiefly in mammary tissues. In the present study we aimed to quantify of $ER{\alpha}$ mRNA and protein expression in breast tissues from the Iranian population using a real-time PCR assay. Twenty nine breast tissues including 19 adenocarcinomas and 10 normal controls were recruited from the Iranian population. mRNA extraction and cDNA synthesis were performed from these tissues using commercial kits. $ER{\alpha}$ mRNA and protein expression was quantified using real-time PCR and immunohistochemistry respectively. The results showed high expression of $ER{\alpha}$ mRNA (68%) and protein (53%) in the majority of breast cancer tissues compared to normal breast tissues (p= 0.035). Also, high $ER{\alpha}$ mRNA was associated with tumour size of breast carcinomas. In this study, we first reported the expression of $ER{\alpha}$ in Iranian patients with breast cancers and demonstrated prevalence of the expression to be similar to breast cancers noted in other populations.

• 한국환경성돌연변이발암원학회지
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• 제22권3호
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• pp.175-182
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• 2002

Endocrine disruptors (EDs) are the chemicals that affect endocrine systems through activation or inhibition of steroid hormone response. It is necessary to have a good system to evaluate rapidly and accurately endocrine-disrupting activities of suspected chemicals and their degradation products. The key targets of EDs are nuclear hormone receptors, which bind to steroid hormones and regulate their gene transcription. We constructed a co-expression system of Gal4p DNA binding domain (DBD)- ligand binding domain of human estrogen receptor $\alpha$ or $\beta$, and Gal4p transactivation domain (TAD)-co-activator AIB-1, SRC-1 or TIF-2 in Saccharomyces cerevisiae with a chromosome-integrated lacZ reporter gene under the control of CYC1 promoter and Gal4p binding site (GAL4 upstream activating sequence, GAL4$_{UAS}$). Expression of this reporter gene was dependent on the presence of estrogen or EDs in the culture medium. We found that the two-hybrid system with combination of the hER$\beta$ LBD and co-activator SRC-1 was most effective in the xenoestrogen-dependent induction of reporter activity. The extent of transcriptional activation by those chemicals correlated with their estrogenic activities measured by other assay systems, indicating that this assay system is efficient and reliable for measuring estrogenic activity. The data in this research demonstrated that the yeast detection system using steroid hormone receptor and co-activator is a useful tool for identifying chemicals that interact with steroid receptors.s.

• 한국발생생물학회지:발생과생식
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• 제11권3호
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• pp.187-193
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• 2007

Ethane 1,2-dimethane sulfonate(EDS)는 Leydig 세포의 선별적 사멸을 유도하는 약물로서 가역적인 테스토스테론 결핍 흰쥐를 만드는데 널리 사용된다. 부정소의 구조와 기능 유지는 크게 보아 정소에서 분비되는 테스토스테론에 의존적이지만, 테스토스테론으로부터 유도되는 dihydroxytestosterone(DHT)와 에스트로겐도 중요한 역할을 한다. 본 연구에서는 EDS 주사 후 7주까지 부정소에서의 스테로이드 호르몬 수용체, cyctochrome P450aromatase(P450arom)와 $5{\alpha}$-reductase의 유전자 발현 양상을 조사하였다. 성숙한 수컷 흰쥐($350{\sim}400\;g$)에 EDS를 1회 복강 주사하고(75 mg/kg i.p.) 주사 후 0, 1, 2, 3, 4, 5, 6, 7주가 경과한 날에 희생하였다. 표적 유전자들의 전사 활성은 반 정량적 역전사 중합효소 반응법(semi-quantitative RT-PCRs)으로 측정하였다. Estrogen receptor alpha($ER{\alpha}$) 전사 수준은 EDS 실험군에서 대조군에 비해 주사 1주후에 유의하게 상승했으나(P<0.01) 2주 후부터는 대조군과 유의적인 차이를 보이지 않았다. Estrogen receptor beta($ER{\beta}$)의 전사 수준은 주사 1주후 EDS 실험군에서 대조군에 비해 유의하게 증가했다가(P<0.05), 2주와 3주에는 감소하였고(P<0.05와 P<0.01), 4주와 6주까지는 변동폭을 보이다가 7주 후에는 대조군에 비해 증가하였다(P<0.05). Androgen receptor(AR) 전사 수준은 주사 2주 후에 유의하게 증가하다가(P<0.01) 3주 후부터는 대조군 수준으로 회복하였다. 반면, P450arom는 주사 1주 후부터 3주까지 급격하게 감소했다가(P<0.01 1주와 2주; P<0.05 3주), 4주에 대조군 수준으로 회복하였다. $5{\alpha}$-reductase type 2($5{\alpha}$-RT2)의 mRNA 수준은 4주 후 유의하게 증가했다가(P<0.01), 이후 대조군 수준으로 회복하였다. 본 연구는 EDS 주사가 성 스테로이드 호르몬 수용체들과 안드로겐 전환 효소들의 전사 활성에 가역적인 변화를 유도함을 보여준 것이다. EDS 주사 모델은 부정소의 생리 조절 기작을 이해하는데 유용할 것으로 사료된다.

• Molecules and Cells
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• 제20권3호
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• pp.378-384
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• 2005

Estrogen metabolites are carcinogenic. The comparative mitogenic activities of $17{\beta}$-estradiol (E2) and four metabolites, 2-hydroxyestradiol (2-OHE2), 4-hydroxyestradiol (4-OHE2), $16{\alpha}$-hydroxyestrone ($16{\alpha}$-OHE1) and 2-methoxyestradiol (2-ME), were determined in estrogen receptor(ER)-positive MCF-7 human breast cancer cells. Each of the E2 metabolites caused proliferation of the MCF-7 cells, but only E2 and $16{\alpha}$-OHE1 induced a greater than 20-fold increases in transcripts of the progesterone receptor (PR) gene, a classical ER-mediated gene. This suggests that the mitogenic action of E2 and $16{\alpha}$-OHE1 could result from their effects on gene expression via the ER. E2 metabolites altered the expression of E2-regulated proteins including heat shock proteins (Hsps). $16{\alpha}$-OHE1 and 2-ME as well as E2 increased levels of Hsp56, Hsp60, $Hsp90{\alpha}$ and Hsp110 transcripts, and the patterns of these inductions resembled that of PR. Hsp56 and Hsp60 protein levels were increased by all the E2 metabolites. Levels of the transcripts of 3 E2-upregulated proteins (XTP3-transactivated protein A, protein disulfide isomerase-associated 4 protein and stathmin 1) and an E2-downregulated protein (aminoacylase 1) were also affected by the E2 metabolites. These results suggest that the altered expression of Hsps (especially Hsp56 and Hsp60) by E2 metabolites such as E2, $16{\alpha}$-OHE1 and 2-ME could be closely linked to their mitogenic action.

• Fisheries and Aquatic Sciences
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• 제4권4호
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• pp.180-185
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• 2001

Al and Cd-induced inhibition of vitellogenin (VTG) production was examined at the estrogen receptor (ER) level in rainbow trout Oncorhynchus mykiss hepatocytes. The binding of $[^3H]$ $estradiol-17\beta\;(E_2)$ to hepatocytes reached a plateau 3 days after addition of $E_2\;(2\times\;10^{-6} M)$to the medium. The binding activity was linearly reduced with the increased concentrations $(-10^{-5}\;M)$ of 4-hydroxy-tamoxifen (4-OHT) and specific binding linearly increased with the increased doses of $[^3H]\;E_2$, indicating that the radioligand bound to ER. Al $(-10^{-4}\;M)$and Cd $(10^{-6}\;M)$ as well as 4-OHT $(10^{-6}\;M)$ significantly reduced the $[^3H]\;E_2$-binding activity by $30­40\%$, while they completely inhibited VTG production. Al and Cd had no effect on $E_2-human$ $ER\alpha$ binding activity at any concentrations used $(-10^5\;nM\;each)$. These results suggested that Al and Cd inhibited VTG production in part by interfereing with the ER level. Inhibitory effects of these metals on the $E_z-dependent$ upregulation of ER activity are also discussed.

• 약학회지
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• 제35권5호
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• pp.394-400
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• 1991

A question whether abnormal responsiveness of hypothalamic catecholaminergic nervous system to ovarian steoid hormones in spontaneously hypertensive rats (SHR) exist was investigated. Four groups of experimental animals were prepared for SHR and normotensive Wistar rats (NW) respectively: 1) intact, 2) ovariectomized (OVX+V), 3) ovariectomized and estrogen treated (OVX+E), 4) ovariectomized and estrogen plus progesterone treated (OVX+E+P) groups. Hypothalami from experimental animals were dissected out and used for determination of .alpha.-adrenergic receptor binding characteristics and catecholamine contents. Norepinephrine(NE) content and B$_{max}$ of $\alpha_1$-adrenergic receptors in hypothalami were greater in intact SHR than in intact NW, but dopamine(DA) content was lower in SHR than in NW. Neither contents of NE and DA nor binding characteristics of $\alpha_1$-adrenergic receptors were different in OVX+V and OVX+E group from intact group of both SHR and NW. Kd and B$_{max}$ of $\alpha_1$-adrenergic receptors in OVX+E+P was lower than that in intact SHR but not in NW. DA content was lower in OVX+E+P than in intact group of SHR and NW. The result of the present study indicates that there is an abnormal responsiveness of hypothalamic catecholaminergic nervous system to ovarian steroid hormones in SHR which may be one of genetically-determined factors probably not responsible for the development of hypertension.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2003년도 추계학술대회
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• pp.135-135
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• 2003

Bisphenol A (BPA) mimics estrogen and its activity is one third to one quarter that of estradiol. BPA, an ubiquitous environmental contaminent has been shown to cause development reproductive toxicity and carcinogenic effect. BPA may do physiological action through ER${\alpha}$ and ER${\beta}$ which are expressed in central nerve system.(omitted)

• Environmental Analysis Health and Toxicology
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• 제26권
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• pp.5.1-5.11
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• 2011

Objectives: In order to identify the possibility of slender bitterling (SB) (Acheilognathus yamatsutae) being used as a test species for estrogenic endocrine disrupting chemicals (EEDCs), we carried out the cloning and sequence characterization of the estrogen receptor (ER). Methods: The ER from a slender bitterling was obtained by reverse transcriptase-polymerase chain reaction (RT-PCR), 5'- and 3'-rapid amplification of cDNA ends (5'-RACE and 3'-RACE) and T-vector cloning. The expression of ER mRNA was also analyzed in six tissues (brain, liver, kidney, gill, gonad, and intestines) by real-time PCR. Results: We obtained an ER from the slender bitterling. The SB ER cDNA was 2189 base pairs (bp) in length and contained a 1707 bp open reading frame that encoded 568 amino acid residues. The SB ER amino acid sequence clustered in a monophyletic group with the $ER{\alpha}$ of other fish, and was more closely related to zebrafish $ER{\alpha}$(88% identity) than to the $ER{\alpha}$ of other fish. The SB ER cDNA was divided into A/B, C, D, E and F domains. The SB ER has conserved important sequences for ER functions, such as the DNA binding domain (D domain), which are consistent with those of other teleosts. Conclusions: The ER of the slender bitterling could provide basic information in toxicological studies of EEDCs in the slender bitterling.

• Asian Pacific Journal of Cancer Prevention
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• 제15권15호
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• pp.6247-6251
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• 2014

Background: The aim of the present study was to investigate the involvement of emodin on the growth of human breast cancer MCF-7 and MDA-MB-231 cells and the estrogen (E2) signal pathway in vitro. Materials and Methods: MTT assays were used to detect the effects of emodin on E2 induced proliferation of MCF-7 and MDA-MB-231 cells. Flow cytometry (FCM) was applied to determine the effect of emodin on E2-induced apoptosis of MCF-7 cells. Western blotting allowed detection of the effects of emodin on the expression of estrogen receptor ${\alpha}$, cyclin D1 and B-cell lymphoma-2 (Bcl-2), mitogen-activated protein kinases (MAPK) and phosphatidylinostiol 3-kinases (PI3K). Luciferase assays were emplyed to assess transcriptional activity of $ER{\alpha}$. Results: Emodin could inhibit E2-induced MCF-7 cell proliferation and anti-apoptosis effects, and arrest the cell cycle in G0/G1 phase, further blocking the effect of E2 on expression and transcriptional activity of $ER{\alpha}$. Moreover, Emodin influenced the ER ${\alpha}$ genomic pathway via downregulation of cyclin D1 and Bcl-2 protein expression, and influenced the non-genomic pathway via decreased PI3K/Akt protein expression. Conclusions: These findings indicate that emodin exerts inhibitory effects on MCF-7 cell proliferation via inhibiting both non-genomic and genomic pathways.

• 대한의생명과학회지
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• 제15권3호
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• pp.179-185
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• 2009

In our previous report, we showed that $PPAR{\gamma}$ does not influence adipogenesis in females with functioning ovaries, indicating that $PPAR{\gamma}$ activity on adipogenesis is associated with sex-related factors. Among the sex-related factors, estrogen has been recognized as a major factor in inhibiting adiposgenesis in females. Thus, we hypothensized that $17{\beta}$-estradiol (E) inhibits 3T3-L1 cell adipogenesis by preventing $PPAR{\gamma}$ activity. E decreased triglyceirde accumulation in differentiated 3T3-L1 cells compared with control group. E also decreased the expression of $PPAR{\gamma}$ mRNA as well as $PPAR{\gamma}$ dependent adipocyte-specific genes, such as adipocyte fatty acid binding protein and tumor necrosis factor $\alpha$. In addition, E not only decreased luciferase reporter activity by $PPAR{\gamma}$, but also transfection of estrogen receptor $\alpha$ ($ER{\alpha}$) or $ER{\beta}$ led to decreases in $PPAR{\gamma}$ reporter gene activation. Moreover, E-activated ERs significantly decreased the luciferase reporter gene activation induced by $PPAR{\gamma}$ transfection, suggesting that estrogen-activated ERs inhibit $PPAR{\gamma}$-dependent transactivation. Accordingly, our results demonstrate that E inhibits the action of $PPAR{\gamma}$ on adipogenesis through E activated ER, providing evidence that lack of estrogen may potentiate $PPAR{\gamma}$ action on adipogenesis.