• Environmental Mutagens and Carcinogens
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• v.26 no.1
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• pp.12-19
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• 2006

Cadmium, a human carcinogen, can induce toxicity in various cell lines and organs. Despite extensive research, the mechanisms of cadmium-induced cell toxicity and estrogenic potential in human are not clear. This study was performed to investigate cadmium-induced toxicity on human breast cancer cells: MCF-7 cells, an estrogen receptor (ER) positive breast cancer cells, and MDA-MB-231 cells, an ER negative breast cancer cells. MCF-7 cells was proved to be more sensitive than the other cell lines (IC50 = $50\;{\mu}M$ at MCF-7 cells and $120{\mu}M$ at MDA-MB-231). The expression of JNK and AP-1 transcription factors such as c-Jun and c-Fos dependent transcription were increased by cadmium treatment. Inhibition of ER activation by ER antagonist (tamoxifen or ICI 182,780) significantly recovered the viablity and inhibited apoptotic cell death. This suggested that cadmium-induced cell death in ER (+) cells was mediated by JNK/AP-1 pathway and this pathway was more stimulated by ER activated by cadmium. Co-treatment of antioxidants such as selenium (Se), butylated hydroxyanisole (BHA), glutathione (GSH), or N-acetyl-L-cysteine (NAC) recovered the cadmium-induced cell death in MCF-7 cells. Cadmium-induced lipid peroxidation was decreased by GSH, NAC, or BHA in MCF-7 cells. The expression of SOD protein was decreased by cadmium ($100{\mu}M$) but recovered by GSH, NAC, BHA, or Se. Our data showed that the cadmium-induced cell toxicity in human breast cancer cells could be protected by the antioxidants (Se, BHA, NAC, GSH, or NAC) and ER antagonist (tamoxifen or ICI 182,780). Therefore, toxicity of cadmium in breast cancer were mediated by oxidative stress and $ER{\alpha}$.

• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.355-356
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• 2006

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.21
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• pp.9233-9239
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• 2014

Background: We aimed to evaluate the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression discordance in matched pairs of primary breast cancer and lymph node metastasis specimens and determine the effect of discordance on prognosis. Materials and Methods: Among all patients diagnosed with lymph node metastases from 2004 to 2007, primary tumors and paired lymph node metastases were resected from 209 patients. The status of ER, PR, and HER2 expression was analyzed immunohistochemically in 200, 194, and 193 patients, respectively. Discordance was correlated with prognosis. Results: Biomarker discordance between primary tumors and paired lymph node metastases was 25.0% (50/200) for ER status, 28.9% (56/194) for PR status, and 14.0% (27/193) for HER2 status. ER positivity was a significant independent predictor of improved survival when analyzed in primary tumors and lymph node metastases. Patients with PR-positive primary tumors and paired lymph node metastases displayed significantly enhanced survival compared to patients with PR-positive primary tumors and PR-negative lymph node metastases. Patients with ER- and PR-positive primary tumors and paired lymph node metastases who received endocrine therapy after surgery displayed significantly better survival than those not receiving endocrine therapy. Similalry treated patients with PR-negative primary tumors and PR-positive paired lymph node metastases also displayed better survival than those not receiving endocrine therapy. Conclusions: Biomarker discordance was observed in matched pairs of primary tumors and lymph node metastases. Such cases displayed poor survival. Thus, it is important to reassess receptor biomarkers used for lymph node metastases.

• Molecules and Cells
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• v.25 no.2
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• pp.289-293
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• 2008

The role of SPOP in the ubiquitination of $ER{\alpha}$ by the Cullin3-based E3 ubiquitin ligase complex was investigated. We showed that the N-terminal region of SPOP containing the MATH domain interacts with the AF-2 domain of $ER{\alpha}$ in cultured human embryonic 293 cells. SPOP was required for coimmunoprecipitation of $ER{\alpha}$ with Cullin3. This is the first report of the essential role of SPOP in $ER{\alpha}$ ubiquitination by the Cullin3-based E3 ubiquitin ligase complex. We also demonstrated repression of the transactivation capability of $ER{\alpha}$ in cultured mammalian cells.

• Development and Reproduction
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• v.11 no.3
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• pp.187-193
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• 2007

Ethane 1,2-dimethane sulfonate(EDS), a Leydig cell specific toxicant, has been widely used to create the reversible testosterone withdrawal rat model. Though the maintenance of epididymal structure and function is highly dependent on the testosterone secreted from testis, its derivatives, dihydroxytestosterone(DHT) and estrogen, might have crucial roles. The aim of present study was to monitor the expression patterns of sex steroid receptors, cytochrome P450 aromatase(P450arom) and $5{\alpha}$-reductase in the rat epididymis up to 7 weeks after EDS injection. Adult male rats($350{\sim}400g$) were injected with a single does of EDS(75 mg/kg i.p.) and sacrificed on weeks 0, 1, 2, 3, 4, 5, 6 and 7. The transcriptional activities of the target genes were evaluated by semi-quantitative RT-PCRs. The transcript level of estrogen receptor alpha($ER{\alpha}$) in EDS group was significantly higher than control level on week 1(P<0.01). After week 2, there was no significant difference in $ER{\alpha}$ levels between EDS group and control. The transcript level of estrogen receptor beta($ER{\beta}$) in EDS group was significantly higher than control level on week 1(P<0.05), lowered on weeks 2 and 3(P<0.05 and P<0.01, respectively), fluctuated during weeks 4 and 6, and elevated on week 7(P<0.05). The androgen receptor (AR) message levels increased significantly week 2(P<0.01), then returned to control level on week 3. In contrast, expression of cytochrome P450 aromatase(P450arom) decreased sharply during weeks $1{\sim}3$(P<0.01 on weeks 1 and 2; P<0.05 on week 3), then went back to control level on week 4. The mRNA level of $5{\alpha}$-reductase type 2($5{\alpha}$-RT2) increased significantly on week 4(P<0.01), then returned to control level. The present study indicated that EDS administration could induce reversible alterations in the transcriptional activities of sex steroid hormone receptors and androgenconverting enzymes in rat epididymis. EDS injection model will be useful to clarify the regulation mechanism of mammalian epididymal physiology.

• Archives of Pharmacal Research
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• v.28 no.12
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• pp.1365-1375
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• 2005

The antiestrogenic effects of marijuana smoke condensate (MSC) and three major cannabinoids, i.e., $\bigtriangleup^{9}$-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN), were evaluated using in vitro bioassays, viz., the human breast cancer cell proliferation assay, the recombinant human estrogen receptor (ER) competitive binding assay, and the reporter gene assay. The inhibitory effects on estrogen were also examined using the ethoxyresorufin-O­deethylase (EROD) assay, the aromatase assay, and the 17$\beta$-estradiol ($E_{2}$) metabolism assay. The results showed that MSC induced the antiestrogenic effect via the ER-mediated pathway, while THC, CBD, and CBN did not have any antiestrogenic activity. This suggests that the combined effects of the marijuana smoke components are responsible for the antiestrogenicity of marijuana use. In addition, MSC induced the CYP1A activity and the $E_{2}$ metabolism, but inhibited the aromatase activity, suggesting that the antiestrogenic activity of MSC is also related to the indirect ER-dependent pathway, as a result of the depletion of the in situ $E_{2}$ level available to bind to the ER. In conclusion, pyrogenic products including polycyclic aromatic hydrocarbons (PAHs) in the non-polar fraction, which is the most biologically active fraction among the seven fractions of MSC, might be responsible for the antiestrogenic effect.

• Archives of Pharmacal Research
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• v.29 no.5
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• pp.354-362
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• 2006

Dietary flavonoids have attracted a great deal of attention as agents for preventing estrogen-related diseases, such as postmenopausal symptoms, and for reducing the risk of estrogen-dependent cancer. Kaempferol is one of the most commonly found dietary phytoestrogen. The aim of this study was to investigate the estrogenic and/or antiestrogenic effect of kaempferol, which can confirm its potency as a preventive agent against estrogen-related diseases. Kaempferol has both estrogenic and antiestrogenic activity, which are biphasic response on estrogen receptor. The estrogenic activity of kaempferol induced via ER-mediated pathway depending on $E_2$ concentration $(\leq\;10^{-12}M)$. Kaempferol $(10^{-5}\;M)$ also caused antiproliferative effect on MCF-7 cell in the presence of $E_2\;(10^{-11}\;M)$ and restored to the addition of excess $E_2\;(10^{-7}\;M)$, which confirms that antiproliferation of kaempferol was induced via ER-dependent pathway. However, at $10^{-4}\;M$, concentration higher than the concentrations at which the estrogenic effects of kaempferol are detected $(10^{-5}\;M)$, kaempferol induced strong antiproliferative effect, but were unaffected by the addition of excess $E_2\;(10^{-7}\;M)$ indicating that kaempferol exerts antiproliferation via ER-independent pathway. In particular, kaempferol blocked the focus formation induced by $E_2$, which confirms that kaempferol might inhibit the malignant transformation caused by estrogens. Therefore, we suggested that kaempferol might regulate a suitable level of estrogenic activity in the body and is expected to have potential beneficial effects in preventing estrogen imbalance diseases (breast cancer, osteoporosis, cardiovascular disease and etc.).

• Molecular & Cellular Toxicology
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• v.2 no.2
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• pp.106-113
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• 2006

Phthalate analogues are a plasticizer and solvent used in industry. Phthalates were classified in the category of "suspected" endocrine disruptors. The purpose of our study was to screen and elucidate the endocrine disrupting activity of seven phthalate analogues. E-screen assay was performed in MCF-7 human breast cancer cells with seven phthalate analogues. In this cell proliferation assay, benzyl butyl phthalate (BBP) and dibutyl phthalate (DBP) showed high estrogenic activity. Their relative proliferation efficiencies (RPE) were 109 and 106%, respectively. In vitro estrogen receptor (ER) binding assay, BBP, di-n-octyl phthalate (DOP) and dinonyl phthalate (DNP) showed weak relative binding affinity (RBA: 0.02%) compared to $17{\beta}-estradiol\;(E2)$ (RBA: 100%). In uterotrophic assay, E2 produced a significant increase, whereas four tested phthalate analogues had potential estrogenic effects in vitro did not increased in uterus weight in immature rats. From these results, we demonstrated that phthalate analogues exhibit weak estrogenic activity in vitro assays at high concentrations. Although phthalates induced an increase in MCF-7 cell proliferation by an estrogenic effect, they could not induce a uterus weight increase in vivo. From these, we may suggest that these phthalate analogues are easily metabolized to inactive forms in vivo. Further investigation in other in vitro and in vivo experimental systems might be required.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.116.1-116.1
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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. We previously found that expose of BPA to immature mice resulted in behavial alternation, suggesting that overexposure of BPA could be neurotoxic. (omitted)

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.159-163
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• 1999

Recent development of the molecular biology techniques has made it possible to characterize and analyze early diagnoses of genetic disorders and economic trait loci. In this study, porcine genomic DNA was extracted from both clotted and dried blood to analyze the porcine estrogen receptor (ER) gene by polymerase chain reaction (PCR). By the methods reported here, genomic DNA extracted from clotted or dried blood was efficient enough to detect ER gene by PCR. Moreover, the PCR-RFLP (restriction fragment length polymorphism) of ER gene was identified by PvuII restriction enzyme. Thus the results obtained from this study show that the clotted and dried blood was useful for identification of the certain genotype in a rapid manner with low cost. Importantly, this study implies that the whole blood can be economically utilized in studies of endocrinology, molecular biology, and genetics by obtaining both serum and DNA simultaneously in an efficient manner.