• BMB Reports
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• v.32 no.5
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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.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.516-521
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• 2014

The mechanisms underlying the refractory effects of flutamide, a first-line oral anti-androgen drug, have not been entirely elucidated. In the present study, we investigated the mechanism of flutamide-induced hormone-refractory prostate cancer cell growth and its modulation by resveratrol, a phytoalexin present in grapes. Resveratrol significantly attenuated interleukin 6 (IL-6)-induced signal transducer and activator of transcription 3 (STAT3) transcriptional activity and dihydrotestosterone (DHT) or IL-6-induced prostate-specific antigen (PSA) transcriptional activity. Furthermore, compared to treatment with DHT or IL-6 alone, combination treatment of cells significantly increased PSA transcriptional activity, and resveratrol markedly diminished DHT plus IL-6-induced STAT3 and PSA transcriptional activities. Thus, the inhibitory effects of resveratrol on IL-6-, DHT-, and flutamide-induced hormone-refractory prostate cancer cell growth are partly mediated by the suppression of STAT3 reporter gene activity, suggesting that resveratrol represents a promising therapy for prostate cancer.

• Natural Product Sciences
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• v.17 no.1
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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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• v.39 no.2
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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.

• The Journal of Korean Medicine
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• v.22 no.2
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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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• v.24 no.3
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• pp.217-226
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• 2009

p53 undergoes various post-translational modifications, including phosphorylation, ubiquitination, sumoylation, acetylation, methylation, and poly(ADP-ribosyl)ation. Modification of p53 widely affects to various functions of p53. Acetylation and phosphorylation of p53 have been studied for regulating its transcriptional activity which is observed in various stress condition. Otherwise, ubiquitination of p53 by Mdm2 has been well-studied as a canonical ubiquitin-mediated proteasomal degradation pathway. Moreover several investigators have recently reported that ubiquitination of p53 modulates not only its proteasome-dependent degradation by poly-ubiquitination but also its localization and transcriptional activity by mono-ubiquitination which usually does not serve the proteasome dependent degradation. Here we review recent studies on the cellular functions of p53 regulated by post-translational modifications, particularly focusing on mechanisms of ubiquitination.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.2
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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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• v.47 no.12
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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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• v.16 no.17
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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.

• Journal of Life Science
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• v.20 no.2
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• pp.275-280
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• 2010

Sulforaphane is a naturally occurring member of the iosothiocyanate family, which reveals chemopreventive capacities including anti-cancer, anti-inflammation and inhibition of MMP-9 activities. In this study, we investigated the effect of sulforaphane on the expression of matrix metalloproteinase-9 (MMP-9) in lipopolysaccharide (LPS)-induced Raw 264.7 cells. Sulforaphane strikingly suppressed the LPS-induced MMP-9 activity and mRNA expression in a dose-dependent manner. In addition, sulforaphane inhibited not only the LPS-induced MMP-9 promoter activity but also LPS-mediated activator protein-1 (AP-1) and nuclear factor-kB (NF-${\kappa}B$) promoter activity. Transient transfection by MMP-9 constructs, in which specific transcriptional factors were mutagenized, indicated that the effects of LPS and sulforaphane were mediated via AP-1 and NF-${\kappa}B$ response elements. We found that sulforaphane had the ability to suppress LPS-induced invasion in vitro. Taken together, these results demonstrated that sulforaphane effectively suppressed LPS-induced MMP-9 expression via modulation of promoter elements (AP-1 and NF-${\kappa}B$) in MMP-9 transcriptional activation.