• BMB Reports
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• v.36 no.2
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• pp.207-213
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• 2003

Peroxisome proliferator-activated receptors (PPARs) are orphan nuclear hormone receptors that are known to control the expression of genes that are involved in lipid homeostasis and energy balance. PPARs activate gene transcription in response to a variety of compounds, including hypolipidemic drugs. Most of these compounds have high affinity to the ligand-binding domain (LBD) of PPARs and cause a conformational change within PPARs. As a result, the receptor is converted to an activated mode that promotes the recruitment fo co-activators such as the steroid receptor co-activator-1 (SRC-1). Based on the activation mechanism of PPARs (the ligand binding to $PPAR{\gamma}$ induces interactions of the receptor with transcriptional co-activators), we performed Western blot and ELISA. These showed that the indomethacin, a $PPAR{\gamma}$ ligand, increased the binding between $PPAR{\gamma}$ and SRC-1 in a ligand dose-dependent manner. These results suggested that the in vitro conformational change of $PPAR{\gamma}$ by ligands was also induced, and increased the levels of the ligand-dependent interaction with SRC-1. Collectively, we developed a novel and useful ELISA system for the mass screening of $PPAR{\gamma}$ ligands. This screening system (based on the interaction between $PPAR{\gamma}$ and SRC-1) may be a promising system in the development of drugs for metabolic disorders.

• Journal of Life Science
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• v.25 no.12
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• pp.1439-1444
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• 2015

Steroid receptor coactivators (SRC) are transcriptional coactivators. Among SRCs, SRC-3 is the most studied in relation to different types of tumors. However, the role of SRC-3 in early lung development and lung cancer has not been well studied. The expression profiles of SRC-3 showed that SRC-3 contributed to bronchial and alveolar development in embryonic lung development. SRC-3 was strongly expressed in Clara cells and type II alveolar cells during fetal lung development (E17.5- E18.5), and SRC-3 was expressed in both cell types in the adult lung. TTF-1 was expressed in the lungs of heterozygote SRC-3 mice and Clara cell-specific-CCSP-TAg tumor mice, along with SRC-3 expression. The expression of TTF-1 was localized at transformed Clara cells and multifocal adenocarcinomas in lung cancer mice. However, SRC-3 was not expressed in the multifocal adenocarcinomas, suggesting that SRC-3 might not be involved in the invasiveness of lung cancer. Cotransfection of TTF-1 in Clara cell-specific mtCC cell lines resulted in significant activation of CCSP expression. However, cotransfection of SRC-3 had no significant effects on transient transfection. These in vivo and in vitro results suggest that SRC-3 does not play a significant role in lung tumor progression. In conclusion, SRC-3 is involved in bronchial and alveolar development in fetal and adult lungs, but it does not play an important role in the progression of Clara cell-derived lung cancer.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1475-1479
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• 2012

Human peroxisome proliferator-activated receptor gamma ($hPPAR{\gamma}$) has been implicated in numerous pathologies, including obesity, diabetes, and cancer. In this study, we verified that amentoflavone is an agonist of $hPPAR{\gamma}$ and probed the molecular basis of its action. It was demonstrated that amentoflavone bound $hPPAR{\gamma}$ with high (picomolar) affinity and increased the binding between $hPPAR{\gamma}$ and steroid receptor coactivator-1 (SRC-1) by approximately 4-fold. Based on a docking study, for the first time, we propose a model of amentoflavone and $hPPAR{\gamma}$ binding in which amentoflavone forms three hydrogen bonds with the side chains of His323, Tyr327, and Arg280 in $hPPAR{\gamma}$ and participates in two hydrophobic interactions.

• BMB Reports
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• v.39 no.3
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• pp.304-310
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• 2006

Transcription factor NF-E2-related factor 2 (Nrf2) regulates the induction of Phase II detoxifying enzymes and antioxidant enzymes in response to many cancer chemopreventive compounds. In this study, we investigated the role of receptor associated coactivator (RAC3) or steroid receptor coactivator-3 (SRC3) and other nuclear co-regulators including CBP/p300 (CREB-binding protein), CARM1 (Coactivator-associated arginine methyltransferase), PRMT1 (Protein arginine methyl-transferase 1), and p/CAF (p300/CBP-associated factor) in the transcriptional activation of a chimeric Gal4-Nrf2-Luciferase system containing the transactivation domain (TAD) of Nrf2 in HepG2 cells. The results indicated that RAC3 up-regulated the transactivation activity of Gal4-Nrf2-(1-370) in a dose-dependent manner. The enhancement of transactivation domain activity of Gal4-Nrf2-(1-370) by RAC3 was dampened in the presence of dominant negative mutants of RAC3. Next we studied the effects of other nuclear co-regulators including CBP/p300, CARM1, PRMT1 and p/CAF, and the results showed that they had different level of positive effects on this transactivation domain activity of Gal4-Nrf2-(1-370). But importantly, synergistic effects of these co-regulators in the presence of RAC3/SRC3 on the transactivation activity of Gal4-Nrf2-(1-370) were observed. In summary, our present study showed for the first time that the 160 RAC3/SRC3 is involved in the functional transactivation of TAD of Nrf2 and that the other nuclear co-regulators such as CBP/p300, CARM1, PRMT1 and p/CAF can also transcriptionally activate this TAD of Nrf2 and that they could further enhance the transactivation activity mediated by RAC3/SRC3.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2717-2721
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• 2011

Peroxisome proliferator-activated receptors (PPARs) are a subfamily of nuclear receptors (NRs). Human peroxisome proliferator-activated receptor gamma (hPPAR${\gamma}$) has been implicated in the pathology of numerous diseases, including obesity, diabetes, and cancer. ELISA-based hPPAR${\gamma}$ activation assay showed that biapigenin increased the binding between hPPAR${\gamma}$ and steroid receptor coactivator-1 (SRC-1) by approximately 3-fold. In order to confirm that biapigenin binds to hPPAR${\gamma}$, fluorescence quenching experiment was performed. The results showed that biapigenin has higher binding affinity to hPPAR${\gamma}$ at nanomolar concentrations compared to indomethacin. Biapigenin showed anticancer activity against HeLa cells. Biapigenin was noncytotoxic against HaCa T cell. All these data implied that biapigenin may be a potent agonist of hPPAR${\gamma}$ with anticancer activity. We will further investigate its anticancer effects against human cervical cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3847-3850
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• 2013

The three homologous members of the p160 SRC family (SRC-1, SRC-2 and SRC-3) mediate the transcriptional functions of nuclear receptors and other transcription factors, and are the most studied of all the transcriptional co-activators. Recent work has indicated that the SRC-3 gene is subject to amplification and overexpression in various human cancers. Some of the molecular mechanisms responsible for SRC overexpression, along with the mechanisms by which SRC-3 promotes breast and prostate cancer cell proliferation and survival, have been identified. However, the function of SRC-3 in bladder cancer remains poorly understood. In the present study, our results indicate that overexpression of SRC-3 promotes bladder cancer cell proliferation whereas knockdown of SRC-3 results in inhibition. At the molecular level, we further established that CXCR4 is a transcriptional target of SRC-3. Therefore, our study first identified that SRC-3 plays a critical role in the bladder cancer, which may be a target beneficial for its prevention and treatment.

• Journal of Life Science
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• v.28 no.12
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• pp.1507-1515
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• 2018

Benign prostatic hyperplasia (BPH) is characterized by prostatic hypertrophy mainly in the elderly. Corni Fructus is reportedly effective in the prevention and treatment of various diseases, but its efficacy on BPH has not been previously studied. In the present study, we investigated whether or not a Corni Fructus water extract (CF) could prevent testosterone-induced prostatic hyperplasia in rats. To induce BPH, castrated rats were subcutaneously injected with testosterone propionate (TP). CF was administered daily by oral gavage, along with the TP injections, and finasteride, a selective inhibitor of $5{\alpha}$-reductase type 2, was used as a positive control. The results show that CF significantly reduces prostate weight and histopathologic changes while also decreasing levels of serum dihydrotestosterone, similar to the finasteride-treated group. CF also suppresses TP-induced $5{\alpha}$-reductase expression and concentration in prostate tissue and serum, respectively. Furthermore, CF markedly inhibited TP-induced expression of the androgen receptor (AR) and the steroid receptor coactivator 1, an AR coactivator, which was associated with a decrease in prostate-specific antigen levels in both serum and prostate tissue. In conclusion, the results of this study indicate that CF weakens BPH status by inactivation of $5{\alpha}$-reductase and AR.

• Tuberculosis and Respiratory Diseases
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• v.50 no.1
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• pp.52-66
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• 2001

Background : NF-${\kappa}B$ is the most important transcriptional factor in IL-8 gene expression. Triptolide is a new compound that recently has been shown to inhibit NF-${\kappa}B$ activation. The purpose of this study is to investigate how triptolide inhibits NF-${\kappa}B$-dependent IL-8 gene transcription in lung epithelial cells and to pilot the potential for the clinical application of triptolide in inflammatory lung diseases. Methods : A549 cells were used and triptolide was provided from Pharmagenesis Company (Palo Alto, CA). In order to examine NF-${\kappa}B$-dependent IL-8 transcriptional activity, we established stable A549 IL-8-NF-${\kappa}B$-luc. cells and performed luciferase assays. IL-8 gene expression was measured by RT-PCR and ELISA. A Western blot was done for the study of $I{\kappa}B{\alpha}$ degradation and an electromobility shift assay was done to analyze NF-${\kappa}B$ DNA binding. p65 specific transactivation was analyzed by a cotransfection study using a Gal4-p65 fusion protein expression system. To investigate the involvement of transcriptional coactivators, we perfomed a transfection study with CBP and SRC-1 expression vectors. Results : We observed that triptolide significantly suppresses NF-${\kappa}B$-dependent IL-8 transcriptional activity induced by IL-$1{\beta}$ and PMA. RT-PCR showed that triptolide represses both IL-$1{\beta}$ and PMA-induced IL-8 mRNA expression and ELISA confirmed this triptolide-mediated IL-8 suppression at the protein level. However, triptolide did not affect $I{\kappa}B{\alpha}$ degradation and NF-$_{\kappa}B$ DNA binding. In a p65-specific transactivation study, triptolide significantly suppressed Gal4-p65T Al and Gal4-p65T A2 activity suggesting that triptolide inhibits NF-${\kappa}B$ activation by inhibiting p65 transactivation. However, this triptolide-mediated inhibition of p65 transactivation was not rescued by the overexpression of CBP or SRC-1, thereby excluding the role of transcriptional coactivators. Conclusions : Triptolide is a new compound that inhibits NF-${\kappa}B$-dependent IL-8 transcriptional activation by inhibiting p65 transactivation, but not by an $I{\kappa}B{\alpha}$-dependent mechanism. This suggests that triptolide may have a therapeutic potential for inflammatory lung diseases.

• Journal of Life Science
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• v.31 no.6
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• pp.550-558
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• 2021

Fructus Corni, the fruit of Cornus officinalis, has long been used for the prevention and treatment of various diseases. We recently suggested that it was effective against benign prostatic hyperplasia (BPH). In this study, we investigated the inhibitory effect of Corni Fructus (CF) water extract on BPH induced by testosterone propionate (TP) in noncastrated and castrated animal models. BPH was induced in Sprague Dawley rats by an intramuscular injection of TP in castrated or noncastrated rats. Finasteride (FINA) treatment was used as a positive control for inhibition of BPH. According to our results, CF administration inhibited excessive enlargement of development of the prostate in both the noncastrated and castrated groups compared to the control and FINA-treated groups. The inhibitory effect of CF on BPH was associated with inhibition of expression of hypoxia-inducible factor-1α, 5α-reductase type 2, steroid receptor coactivator-1, androgen receptor (AR), and prostate-specific antigen. Serum levels of the stress hormone cortisol increased during BPH induction by TP in both the noncastrated and castrated groups, but they were attenuated significantly by CF administration. However, insulin and IGF-1 levels were not increased in the BPH-induced groups and CF, and no effective results were found by CF administration. These results point to a beneficial effect of CF on BPH through inhibition of AR signaling pathway activity and imply that CF shows excellent potential as a therapeutic agent for the prevention and treatment of BPH.