• 한국발생생물학회지:발생과생식
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• 제11권1호
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• pp.43-47
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• 2007

Transforming growth $factor-{\beta}(TGF-{\beta})$ 신호의 매개자 역할을 하는 Smad 계열 단백질은 발생과정에 중요한 역할을 한다고 알려져 있다. Estrogen receptor(ER)와 구조적으로 유사한 estrogen receptor-related receptor(ERR)은 포유동물에서 후기 배발생기에 외배엽 형성과 관련이 되어 있는 고아핵수용체이다. 본 연구에서는 해양무척추동물의 초기발생과정과 계절번식기 동안에 Smad3와 ERR의 유전자 발현이 발생과정과 성숙에 어떠한 연관성을 갖고 있는지 알아보기 위하여, 동해안 연안에 주로 서식하는 극피동물문 둥근성게과 둥근성게(Strongylocentrotus nudus)를 재료로 하여 계절별 및 배발생 과정중에 Smad3와 $ERR{\beta}$ like 1의 mRNA 농도를 real-time PCR 방법으로 조사하였다. Smad3 mRNA는 샘플링을 시작한 2004년 2월의 생식소와 비교하면 4월부터 그 농도가 증가하기 시작하여 6월까지 증가하였으며, 산란기인 8월에 감소하였다가 10월부터 12월까지 높은 수준을 유지하였다. $ERR{\beta}$ like 1 mRNA는 6월까지 낮은 수준이었으나, 산란기인 8월에 급증한 후 다시 감소하였다. 수정란부터 초기 유생기까지 발생과정을 분석한 결과, Smad3 mRNA는 8세포기 및 16세포기에 높은 발현이 관측되었다. 한편, $ERR{\beta}$ like 1 mRNA는 포배기, 낭배기, 초기 유생기에 현저하게 높은 발현패턴을 보였다. 이상의 결과로부터 둥근성게의 산란기 및 발생배의 발생후기에 $ERR{\beta}$ like 1이 중요한 역할을 담당할 것으로 추정되며, 초기 난할시기에는 Smad3의 관련성이 시사되었다.

• Toxicological Research
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• 제26권4호
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• pp.237-243
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• 2010

Endocrine disrupting chemicals (EDCs) have been shown to interfere with physiological systems, i.e., adversely affecting hormone balance (endocrine system), or disrupting normal function, in the female and male reproductive organs. Although endocrine disruption is a global concern for human health, its impact and significance and the screening strategy for detecting these synthetic or man-made chemicals are not clearly understood in female and male reproductive functions. Thus, in this review, we summarize the interference of environmental EDCs on reproductive development and function, and toxicological mechanism(s) of EDCs in in vitro and in vivo models of male and female reproductive system. In addition, this review highlights the effect of exposure to multiple EDCs on reproductive functions, and brings attention to their toxicological mechanism(s) through estrogen receptors.

• 한국발생생물학회지:발생과생식
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• 제9권2호
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• pp.85-93
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• 2005

스테로이드 호르몬인 에스트로겐은 여러 조직의 발생 및 분화에 영향을 주는 것으로 알려져 있다. 최근 에스트로겐의 영향을 평가하는데 있어 전통적인 여성 호르몬이라는 인식을 탈피하여 수컷 생식계상의 역할에 관한 연구가 활발하게 이루어지고 있다. 특히 내분비계 교란물질에 관한 다양한 연구 결과가 보고되면서, 수컷에서의 에스트로겐 역할에 대한 관심이 증대되고 있는 실정이다. 따라서 에스트로겐의 정확한 역할을 파악하기 위해서 발생 단계에 따른 에스트로겐 수용체의 수컷 생식기관 내 분포를 정리해 보고, 내분비계 교란물질의 노출에 따른 수컷 생식계의 발생 및 분화 이상과 정자형성과정의 장애 등을 알아보고자 하였다. 끝으로 외인성 화학물의 에스트로겐성을 평가하기 위한 지표인자들을 정리하여, 남성 생식기관의 발생, 분화, 기능에 관련된 에스트로겐의 역할에 대한 실제적인 정보를 얻을 수 있을 것으로 사료된다.

• Archives of Pharmacal Research
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• 제26권1호
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• pp.58-63
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• 2003

Ginseng has been recommended to alleviate the menopausal symptoms, which indicates that components of ginseng very likely contain estrogenic activity. We have examined the possibility that a component of Panax ginseng, $ginsenoside-R_{b1}$ acts by binding to estrogen receptor. We have investigated the estrogenic activity of $ginsenoside-R_{b1}$ in a transient transfection system using estrogen-responsive luciferase plasmids in MCF-7 cells. $ginsenoside-R_{b1}$ activated the transcription of the estrogen-responsive luciferase reporter gene in MCF-7 breast cancer cells at a concentration of 50 $\mu$M. Activation was inhibited by the specific estrogen receptor antagonist ICI 182,780, indicating that the estrogenic effect of $ginsenoside-R_{b1}$ is estrogen receptor dependent. Next, we evaluated the ability of $ginsenoside-R_{b1}$ to induce the estrogen-responsive gene c-fos by semi-quantitative RT-PCR assays and Western analyses. $ginsenoside-R_{b1}$ increased c-fos both at mRNA and protein levels. However, $ginsenoside-R_{b1}$ failed to activate the glucocorticoid receptor, the retinoic acid receptor, or the androgen receptor in CV-1 cells transiently transfected with the corresponding steroid hormone receptors and hormone responsive reporter plasmids. These data support our hypothesis that $ginsenoside-R_{b1}$ acts a weak phytoestrogen, presumably by binding and activating the estrogen receptor.

• 대한의생명과학회지
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• 제11권2호
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• pp.175-183
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• 2005

The two major isoflavones in soy, genistein and daidzein, are well known to prevent hormone-dependent cancers by their anti estrogenic activity. The exact molecular mechanisms for the protective action are, however, not provided yet. It has been reported that genistein and daidzein have a potential anticancer activity through their antiproliferative effect in many hormone-dependent cancer cell lines. Transforming growth $factor-\beta1(TGF-\beta1)$ has also been found to have cell growth inhibitory effect, especially in mammary epithelial cells. This knowledge led to a hypothetical mechanism that the soy isoflavones-induced growth inhibitory effect can be derived from the regulation of $TGF-\beta1$ and $TGF-\beta$ receptors. In order to test this hypothesis, the effects of the soy isoflavones at various concentrations and periods on the expression of $TGF-\beta1$and $TGF-\beta$ receptors were investigated by using Northern blot analysis in human breast carcinoma epithelial cell lines, an estrogen receptor positive cell line (MCF-7) and an estrogen receptor negative cell line (MDA-MB-231). As a result, only genistein has shown a profound dose-dependent effect on $TGF-\beta1$ expression in the $ER^+$ cell line within the range of doses tested, and the expression levels are correspondent to their inhibitory activities of cell growth. Moreover, daidzein showed down-regulated $TGF-\beta1$ expression at a low dose, the cell growth proliferation was promoted at the same condition. Therefore, antiproliferative activity of the soy isoflavones can be mediated by $TGF-\beta1$ expression, and the effects are mainly, if not all, occurred by ER dependent pathway. The expression of $TGF-\beta$ receptors was induced at a lower dose than the one for $TGF-{\beta}1$ induction regardless of the presence of ER, and the expression patterns are similar to those of the cell growth inhibition. These results indicated that the regulation of $TGF-\beta$ receptor expression as well, prior to $TGF-\beta1$ expression, may be involved in the antiproliferative activity of soy isoflavones. Little or no expression of $TGF-\beta$ receptors was found in the MCF-7 and MDA-MB-231 cells, suggesting refractory properties of the cells to growth inhibitory effect of the $TGF-\beta$. The soy isoflavones can seemingly restore the sensitivity of growth inhibitory responses to $TGF-\beta1$ by re-inducing $TGF-\beta$ receptors expression. In conclusions, our findings presented in this study show that the antitumorigenic activity of the soy isoflavones could be mediated by not only $TGF-\beta1$induction but $TGF-\beta$ receptor restoration. Thus, soy isoflavones could be good model molecules to develop new nonsteroidal antiestrogenic chemopreventive agents, associated with, regulation of $TGF-\beta$ and its receptors.

• Journal of Microbiology and Biotechnology
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• 제22권3호
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• pp.378-384
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• 2012

In aquatic invertebrates, particularly marine gastropods, organotin compounds induce irreversible sexual abnormality in females, which is termed imposex, at very low concentrations. Organotin compounds are agonists for nuclear receptors such as RXRs and $PPAR{\gamma}$. However, the imposex phenomenon has not been reported to act as an antagonist on estrogen receptors in other species, including vertebrates and invertebrates. In order to gain insights into the antagonistic activity of organotin compounds on estrogen receptors (ERs), we examined the inhibitive effect of these compounds on estradiol-dependent ${\beta}$-galactosidase activity using the yeast two-hybrid detection system consisting of a combination of the human estrogen receptor ($hER{\beta}$) ligand-binding domain and the co-activator steroid receptor co-activator-1 (SRC1). Tributyltin-hydroxide (TBT-OH) and triphenyltin-chlorine (TPT-Cl) exhibited an inhibitive effect on $E_2$-dependent transcriptional activity, similar to antagonistic chemicals such as 4-hydroxytamoxifen (OHT) or ICI 182,780, at a very low concentration of $10^{-14}$ M TBT or $10^{-10}$ M TPT, respectively. The yeast growth and transcriptional activity with transcriptional factor GAL4 did not exhibit any effect at the tested concentration of TBT or TPT. Moreover, the yeast two-hybrid system using the interaction between p53 and the T antigen of SV40 large did not describe any effect at the tested concentration of OHT or ICI 182,780. However, the interaction between p53 and T antigen was inhibited at a TBT or TPT concentration of $10^{-9}$ M, respectively. These results indicate that TBT and TPT act as inhibitors of ER-dependent reporter gene transcriptional activation and of the interaction between $hER{\beta}$ LBD and the co-activator SRC1 in the yeast two-hybrid system. Consequently, our data could partly explain the occurrence of organotin compound-induced imposex on the endocrine system of mammals, including humans.

• BMB Reports
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• 제44권7호
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• pp.452-457
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• 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.

• Toxicological Research
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• 제17권1호
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• pp.65-71
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• 2001

The key targets of endocrine disruptors are nuclear hormone receptors, which bind to steroid hormones and regulate their gene transcription. A yeast-based steroid hormone receptor gene trascription assay was previously developed for the evaluation of chemicals with endocrine modulating activity. The yeast transformants used in this assay contain the human estrogen receptor along with the appropriate steroid response elements upstream of the $\beta$-galactosidase reporter gene. We tried to evaluate several natural and synthetic steroids of their potential to interact directly with the steroid receptor. Some putative endocrine disruptors, including nonylphenol, are weakly estrogenic. But the combined treatment oj these chemicals with di-(2-ethylhexyl)phthalate (DEHP) significantly increased the $\beta$-galactosidase activity in the yeast transformant. These results suggest that we also have to consider the synergistic effects of endocrine disruptors. In this study, we showed that yeast-based bioassay is a valuable tool for screening potential endocrine disruptors and quantitative determination of estrogenicity. And the possibility that the estrogen receptor binds multiple environmental chemicals adds another level of complexity to the interaction between the endocrine disruptors and the human hormone system.

• Toxicological Research
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• 제31권4호
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• pp.331-337
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• 2015

Synthetic pyrethroids (SPs) are the most common pesticides which are recently used for indoor pest control. The widespread use of SPs has resulted in the increased exposure to wild animals and humans. Recently, some SPs are suspected as endocrine disrupting chemicals (EDCs) and have been assessed for their potential estrogenicity by adopting various analyzing assays. In this study, we examined the estrogenic effects of lambda-cyhalothrin (LC) and cypermethrin (CP), the most commonly used pesticides in Korea, using BG-1 ovarian cancer cells expressing estrogen receptors (ERs). To evaluate the estrogenic activities of two SPs, LC and CP, we employed MTT assay and reverse-transcription polymerase chain reaction (RT-PCR) in LC or CP treated BG-1 ovarian cancer cells. In MTT assay, LC ($10^{-6}M$) and CP ($10^{-5}M$) significantly induced the growth of BG-1 cancer cells. LC or CP-induced cell growth was antagonized by addition of ICI 182,720 ($10^{-8}M$), an ER antagonist, suggesting that this effect appears to be mediated by an ER-dependent manner. Moreover, RT-PCR results showed that transcriptional level of cyclin D1, a cell cycle-regulating gene, was significantly up-regulated by LC and CP, while these effects were reversed by co-treatment of ICI 182,780. However, p21, a cyclin D-ckd-4 inhibitor gene, was not altered by LC or CP. Moreover, $ER{\alpha}$ expression was not significantly changed by LC and CP, while down-regulated by E2. Finally, in xenografted mouse model transplanted with human BG-1 ovarian cancer cells, E2 significantly increased the tumor volume compare to a negative control, but LC did not. Taken together, these results suggest that LC and CP may possess estrogenic potentials by stimulating the growth of BG-1 ovarian cancer cells via partially ER signaling pathway associated with cell cycle as did E2, but this estrogenic effect was not found in in vivo mouse model.

• 대한세포병리학회지
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• 제5권1호
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• pp.10-14
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• 1994

The expression of sex steroid hormone receptors by neoplastic cells is an important predictor of response to hormone therapy. Thus, the selection of treatment modality is often based on the identification of receptors in tumor tissue. Various monoclonal antibodies of high specificity are now available for analyzing the estrogen receptor (ER). With these antibodies, biochemical enzyme immunoassay and immunohistochemistry using histologic sections have been used for ER analysis. We used fine needle aspirates from 15 human primary breast carinomas for the analysis of ERs. The semiquantitative receptor values obtained in cytologic specimens were correlated well with those from histologic specimens. The results of ER in fine needle aspirates were concordant with ER in histologic specimens(r=0.94). Only three cases showed a little difference in staining intensity and proportion of positive cells. Our results showed a good correlation between the receptor values determined in cytologic smears and those determined in tissue sections. It is suggested that measurement of the ER in cytologic smears may be a reliable technique which can be performed on aspiration cytologic samples.