• BMB Reports
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• 제32권5호
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• pp.468-473
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• 1999

Nuclear Factor 1 (NF1) proteins are a family of transcriptional factors consisting of four different types: NF1-A, -B, -C, and -X. Some NF1 transcription factors contain a heptasequence motif, SPTSPSY, which is found as a repeat sequence in the carboxy terminal domain (CTD) of the largest subunit of RNA polymerase II. A similar heptasequence, SPTSPTY, is contained in rat liver NF1-A at a position between residues 469 and 475. In order to investigate the roles of the individual amino acids of the heptasequence of rat liver NF1-A in transcriptional activation, we systematically substituted single and multiple amino acid residues with alanine residue(s) and evaluated the transcriptional activities of the mutated NF1-A. Substitution of a single amino acid reduced transcriptional activity by 10 to 30%, except for the proline residue at position 473, whose substitution with alanine did not affect transcriptional activity. However, changes of all four serine and threonine residues to alanine or of the tyrosine residue along with the serine residue at position 469 to alanine reduced the activity to almost background levels. Our results indicate that multiple serine and threonine residues, rather than a single residue, may be involved in the modulation of the transcriptional activities of the factor. Involvement of the tyrosine residue is also implicated.

• 한국식품과학회지
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• 제46권4호
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• pp.516-521
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• 2014

전립선암은 발병률이 높은 암종 중에 하나이다. 전립선 치료제인 flutamide는 androgen 수용체의 호르몬 치료제로서 내성효과에 대한 기본 메커니즘은 명확하지 않다. 본 연구에서는 flutamide에 의해 유도되는 호르몬 불응성 전립선 암세포 성장에서 포도 성분인 resveratrol의 억제효과를 조사하였다. 본 연구의 결과를 통해 호르몬 비의존적인 신호전달의 전환으로 유발되는 호르몬 불응성 전립선 암에서 resveratrol은 예방 및 항암효과에 기여할 것이라 판단된다.

• Natural Product Sciences
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• 제17권1호
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• pp.26-32
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• 2011

Novel tyrosinase inhibitors are important for pigmentation in the skin. Following extraction of tyrosinase inhibitors from edible vegetables or fruits, we found that the Prunus persica flesh extract (PPFE) exhibited potential inhibitory activity for melanogenesis. PPFE showed tyrosinase inhibitory activity in an enzymatic assay and PPFE also significantly inhibited the melanin formation in cultured mouse melan-a cells. Moreover, real-time RT-PCR analysis revealed that the inhibition of melanin production by PPFE was closely related to marked suppression of mRNA expression of tyrosinase and tyrosinase-related protein-1 and -2 (TRP-1 and TRP-2) in melan-a cells. Further investigation found that the modulation of tyrosinase expression by PPFE was associated with the transcriptional regulation of the microphthalmia-associated transcription factor (MITF). PPFE inhibited the promoter activity of MITF and suppressed MITF mRNA expression in melan-a cells. These results indicate that PPFE down-regulates melanogenesis-associated gene expression through MITF-mediated transcriptional regulation and these events might be related to the hypopigmentary effects of PPFE.

• Molecules and Cells
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• 제39권2호
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• pp.156-162
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• 2016

Estrogen receptor ${\alpha}$ (ER-${\alpha}$), which is involved in bone metabolism and breast cancer, has been shown to have transcriptional targets. Dlx3 is essential for the skeletal development and plays an important role in osteoblast differentiation. Various osteogenic stimulators and transcription factors can induce the protein expression of Dlx3. However, the regulatory function of ER-${\alpha}$ in the Dlx3 mediated osteogenic process remains unknown. Therefore, we investigated the regulation of Dlx3 and found that ER-${\alpha}$ is a positive regulator of Dlx3 transcription in BMP2-induced osteoblast differentiation. We also found that ER-${\alpha}$ interacts with Dlx3 and increases its transcriptional activity and DNA binding affinity. Furthermore, we demonstrated that the regulation of Dlx3 activity by ER-${\alpha}$ is independent of the ligand (estradiol) binding domain. These results indicate that Dlx3 is a novel target of ER-${\alpha}$, and that ER-${\alpha}$ regulates the osteoblast differentiation through modulation of Dlx3 expression and/or interaction with Dlx3.

• 대한한의학회지
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• 제22권2호
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• pp.64-74
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• 2001

Objectives : The effects of aqueous extract of Backhapgogumtanggami-bang (BGTG, a newly devised herb medicine) on the induction of apoptotic cell death were investigated in human lymphoid origin leukemia cell lines, HL-60. Methods : Cells were treated with various concentrations and $400{\;}\mu\textrm{g}/ml$ BGTG for 12 hr. Genomic DNA was isolated and separated on 1.8% agarose gels. Lysates from the cells were used to measure the activity of caspase-2, -3, -8, and -9 protease by using fluorogenic peptide. Cells were preincubated with SB-203580 for 30 min. Nuclear protein from the cells was incubated with oliginucleotide probe of AP-l and NF-kB. Nuclear extracts from the cells were isolated and reacted with antibodies. Results : The viability of HL-60 cells were markedly decreased by BGTG extract in a dose- and time-dependent manner. BGTG extract induced the apoptotic death of HL-60 cells which was characterized by the DNA fragmentation. The activations of Caspase-2, 3, and 9 were induced by BGTG. However, selective inhibition of the p38 mitogen-activated protein kinase pathways by SB-203580 did not affect the extent of BGTG extract-induced cell death. Furthermore, we observed the transient activations of transcriptional factors such as AP-l and NF-kB. Conclusions : These results suggest that BGTG extract induced apoptotic death of HL-60 cells and caspase activations as well as the modulation of transcriptional factors such as AP-1 and NF-kB.

• KSBB Journal
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• 제24권3호
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• pp.217-226
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• 2009

p53은 전사인자로서 세포의 사멸이나 세포주기 조절 등 다양한 세포 활성을 보이기 때문에 일반적인 환경에서는 매우 낮은 수준으로 단백질 양이 확인된다. p53의 단백질 양과 활성은 다양한 세포 내 신호에 의하여 이루어지는 후전사 변형을 통하여 조절 받는다. 이중 유비퀴틴화는 세포 내에서 p53 단백질의 발현 수준이 낮게 유지되는 것이 가능하게 하는 대표적인 기전이다. 이러한 기전을 일으키는 대표적인 p53의 E3 ligase로는 mdm2, Pirh2, COP1, ARF-BP1 등이 보고되어 있으며, 각각 negative feedback loop나 다른 기전을 통하여 p53 단백질의 분해를 유도하여 세포의 항상성을 조절한다. 이 밖에도 p53은 mdm2나 WWP1, UBC13, MSL2와 같은 E3 ligase로 인해서 모노 유비퀴틴화 되고, p53의 세포 내 위치가 조절되어 전사인자로서의 활성이 억제된다. p53의 세포 내 위치와는 관계없이 p53의 전사인자로써의 활성 또한 아세틸화와 유비퀴틴화의 경쟁적 반응으로 인해 조절 될 수 있다. E4F1에 의한 유비퀴틴화는 세포주기와 관련된 유전자의 발현을 증가시키되 세포사멸 관련 유전자의 발현은 감소시키는 것으로 보아 p53의 수많은 downstream gene의 발현 또한 유비퀴틴화를 통해 조절 될 수 있음이 제시되었다. 앞으로의 연구는 신규 E3 ligase에 의한 p53의 유비퀴틴화 기전 연구 뿐 아니라 이와 관련된 다른 변형과의 관계에 대한 연구 또한 매우 중요하게 부각되어 질 것으로 예상된다.

• The Korean Journal of Physiology and Pharmacology
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• 제21권2호
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• pp.205-213
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• 2017

Quercetin, a plant-derived flavonoid found in fruits, vegetables and tea, has been known to possess bioactive properties such as anti-oxidant, anti-inflammatory and anti-cancer. In this study, anti-cancer effect of quercetin and its underlying mechanisms in triple-negative breast cancer cells was investigated. MTT assay showed that quercetin reduced breast cancer cell viability in a time and dose dependent manner. For this, quercetin not only increased cell apoptosis but also inhibited cell cycle progression. Moreover, quercetin increased FasL mRNA expression and p51, p21 and GADD45 signaling activities. We also observed that quercetin induced protein level, transcriptional activity and nuclear translocation of Foxo3a. Knockdown of Foxo3a caused significant reduction in the effect of quercetin on cell apoptosis and cell cycle arrest. In addition, treatment of JNK inhibitor (SP 600125) abolished quercetin-stimulated Foxo3a activity, suggesting JNK as a possible upstream signaling in regulation of Foxo3a activity. Knockdown of Foxo3a and inhibition of JNK activity reduced the signaling activities of p53, p21 and GADD45, triggered by quercetin. Taken together, our study suggests that quercetin induces apoptosis and cell cycle arrest via modification of Foxo3a signaling in triple-negative breast cancer cells.

• BMB Reports
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• 제47권12호
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• pp.685-690
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• 2014

The Ras/Raf/MEK/Erk signaling pathway is important for regulation of cell growth, proliferation, differentiation, survival, and apoptosis in response to a variety of extracellular stimuli. Lack of Erk MAPK activation is observed in several cancer cells despite active activation of Ras. However, little is known about the modulation of Erk1/2 activity by active Ras. Here, we show that overexpression of active H-Ras (H-RasG12R) in NIH3T3 fibroblasts impaired FGF2-induced Erk1/2 phosphorylation, as compared to wild-type cells. Northern blot analysis revealed that prolonged expression of active Ras increased MAP kinase phosphatase 3 (MKP3) mRNA expression, a negative regulator of Erk MAPK. Inhibition of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway abrogated active Ras-induced up-regulation of MKP3 expression, leading to the rescue of Erk1/2 phosphorylation. Our results demonstrated that the Ras/Raf/MEK/Erk signaling cascade is negatively regulated by the PI3K/Aktdependent transcriptional activation of the MKP3 gene.

• Asian Pacific Journal of Cancer Prevention
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• 제16권17호
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• pp.7393-7400
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• 2015

Matrix metalloproteinase (MMP) 9, a key member of multifunctional family of zinc dependent endopeptidases has been found to be upregulated during inflammation and in some cancers. MMPs cleave extracellular matrix (ECM) proteins and play critical roles in cellular apoptosis, angiogenesis, tumor growth and metastasis. Several genetic polymorphisms have been identified that show allele specific effects on MMP9 regulation and are associated with gastric cancer, the fourth most common malignancy in the world. Besides Helicobacter pylori infection, genetic predisposition is another documented risk factor for gastric carcinoma. The single nucleotide polymorphism (SNP) at position -1562C/T of MMP9 results in the modulation for binding of transcription factors to the MMP9 gene promoter and thereby causes differences in protein expression and enzymatic activity. MMP9 transcriptional regulation during gastric cancer development remains poorly known although several studies have demonstrated associations between MMP9 -1562 C/T polymorphism with different diseases. Knowledge on mechanisms of MMP9 upregulation during gastric cancer may provide new paradigm in diagnostics and therapeutics.

• 생명과학회지
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• 제20권2호
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• pp.275-280
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• 2010

Sulforaphane은 십자가화 채소에 존재하는 화합물로 항염증, 항암 및 신생혈관 생성의 억제 효과가 알려짐으로써 최근 많은 연구가 활발히 이루어지고 있으나, LPS에 의한 MMP-9 활성 조절에 대한 연구는 매우 미흡한 편이다. 따라서 본 연구에서 sulforaphane이 LPS 유도에 의한 MMP-9 활성에 미치는 영향에 대해서 조사해 보았다. Raw 264.7 세포에 sulforaphane을 전처리 한 후 LPS를 처리하여 gelatin zymography를 실시해 본 결과, LPS에 의해 유도된 MMP-9 활성 증가가 sulforaphane 농도 의존적으로 감소됨을 확인 하였다. 또한 RT-PCR과 MMP-9의 luciferase assay를 통한 실험에서 sulforaphane의 MMP-9 억제효과가 전사단계에서 조절됨을 추측 할 수 있었다. MMP-9 promoter 부위에 여러 가지의 전사조절인자 결합부위가 존재한다. 특히 AP-1과 NF-${\kappa}B$가 중요 전사조절인자로 작용하여 MMP-9 발현조절에 관여한다. 본 실험에서 sulforaphane에 의한 MMP-9 억제효과 기전에 이들 전사조절인자들의 중요한 역할을 조사하였다. AP-1과 NF-${\kappa}B$ 결합부위를 변형 시킨 vector를 transfection하여 MMP-9의 promoter 활성을 측정한 결과, 정상 vector에 비해 그 활성도가 현저히 떨어짐을 확인하였고, LPS에 의해 증가되는 AP-1과 NF-${\kappa}B$의 basal promoter 활성 또한 sulforaphane에 의해 감소됨을 관찰 할 수 있었다. 이상의 결과에서 sulforaphane의 MMP-9 활성억제효과는 AP-1과 NF-${\kappa}B$와 같은 전사인자들이 MMP-9의 전사를 조절함으로써 일어나는 것임을 알 수 있었다. 그리고 sulforaphane은 세포의 invasion능력 또한 효과적으로 억제시킴을 관찰 할 수 있었는데 이는 MMP-9 활성억제효과와 밀접한 관련이 있음을 추측 할 수 있었다.