• Archives of Pharmacal Research
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• v.23 no.6
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• pp.605-612
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• 2000

Green tea polyphenols (GTP) have been demonstrated to suppress tumorigenesis in several chemical-induced animal carcinogenesis models, and predicted as promising chemopreventive agents in human. Recent studies of GTP extracts showed the involvement of mitogen-activated protein kinases (MAPKs) in the regulation of Phase II enzymes gene expression and induction of apoptosis. In the current work we compared the biological actions of five green tea catechins: (1) induction of ARE reporter gene, (2) activation of MAP kinases, (3) cytotoxicity in human hepatoma HepG2-C8 cells, and (4) caspase activation in human cervical squamous carcinoma HeLa cells. For the induction of phase IIgene assay, (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) potently induced antioxidant response element (ARE)-mediated luciferase activity, with induction observed at 25 $\mu\textrm{m}$with EGCG. The induction of ARE reporter gene appears to be structurally related to the 3-gallate group. Comparing the activation of MAPK by the five polyphenols, only EGCG showed potent activation of all three MAPKs (ERK, JNK and p38) in a dose- and time-dependent manner, whereas EGC activated ERK and p38. In the concentration range of 25 $\mu\textrm{m}$ to 1 mM, EGCG and ECG strongly suppressed HepG2-ARE-C8 cell-growth. To elucidate the mechanisms of green tea polyphenol-induced apoptosis, we measured the activation of an important cell death protein, caspase-3 induced by EGCG, and found that caspase-3 was activated in a dose- and time-dependent manner. Interestingly, the activation of caspase-3 was a relatively late event (peaked at 16 h), whereas activation of MAPKs was much earlier (peaked at 2 h). It is possible, that at low concentrations of EGCG, activation of MAPK leads to ARE-mediated gene expression including phase II detoxifying enzymes. Whereas at higher concentrations of EGCG, sustained activation of MAPKs such as JNK leads to apoptosis. These mechanisms are currently under investigation in our laboratory. As the most abundant catechin in GTP extract, we found that EGCG potently induced ARE-mediated gene expression, activated MAP kinase pathway, stimulated caspase-3 activity, and induced apoptosis. These mechanisms together with others, may contribute to the overall chemopreventive function of EGCG itself as well as the GTP.

• Animal Bioscience
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• v.34 no.6
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• pp.957-966
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• 2021

Objective: Ovarian follicular development, which dependent on the proliferation and differentiation of granulosa cells (GCs), is a complex biological process in which miRNA plays an important role. Our previous study showed that miR-458b-5p is associated with ovarian follicular development in chicken. The detailed function and molecular mechanism of miR-458b-5p in GCs is unclear. Methods: The luciferase reporter assay was used to verify the targeting relationship between miR-458b-5p and catenin beta-1 (CTNNB1), which is an important transcriptional regulatory factor of the Wnt/β-catenin pathway. The cell counting kit-8 (CCK-8) assay, flow cytometry with propidium iodide (PI) and annexin V-fluorescein isothiocyanate (FITC) labeling were applied to explore the effect of miR-458b-5p on proliferation, cell cycle and apoptosis of chicken GCs. Quantitative real-time polymerase chain reaction and Western blot were used to detect the mRNA and protein expression levels. Results: We demonstrated that the expression of miR-458b-5p and CTNNB1 showed the opposite relationship in GCs and theca cells of hierarchical follicles. The luciferase reporter assay confirmed that CTNNB1 is the direct target of miR-458b-5p. Using CCK-8 assay and flow cytometry with PI and Annexin V-FITC labeling, we observed that transfection with the miR-458b-5p mimics significantly reduced proliferation and has no effects on apoptosis of chicken GCs. In addition, miR-458b-5p decreased the mRNA and protein expression of CD44 molecule and matrix metallopeptidase 7, which are the downstream effectors of CTNNB1 in Wnt/β-Catenin pathway and play functional roles in cell proliferation. Conclusion: Taken together, the data indicate that miR-458b-5p regulates ovarian GCs proliferation through Wnt/β-catenin signaling pathway by targeting CTNNB1, suggesting that miR-458b-5p and its target gene CTNNB1 may potentially play a role in chicken ovarian follicular development.

• Toxicological Research
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• v.22 no.3
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• pp.293-299
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• 2006

We demonstrate that magnolol, a hydroxylated biphenyl compound isolated from Magnolia officinalis, inhibits LPS-induced expression of iNOS gene in RAW 264.7 cells(murine macrophage cell line). Treatment of RAW 264.7 cells with magnolol inhibited LPS-stimulated nitric oxide production in a dose-related manner. RT-PCR analysis showed that the decrease of NO was due to the inhibition of iNOS gene expression. Western immunoblot analysis of phosphorylate p38 kinase showed magnolol significantly inhibited the phosphorylation of p38 kinase which is important in the regulation of iNOS gene expression. The specific p38 inhibiter SB203580 abrogated the LPS-induced NO generation and iNOS expression, whereas the selective MEK-1 inhibitor PD98059 did not affect the NO induction. Immunostaining of p65 and reporter gene assay showed that magnolol inhibited NF-${\kappa}/Rel$ nuclear translocation and transcriptional activation, respectively. Collectively, this series of experiments indicates that magnolol inhibits iNOS gene expression by blocking NF-k/Rel and p38 kinase signaling. Due to the critical role that NO release plays in mediating inflammatory responses, the inhibitory effects of magnolol or iNOS suggest that magnolol may represent a useful anti-inflammatory agent.

• Journal of Plant Biotechnology
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• v.32 no.2
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• pp.91-95
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• 2005

Agrobacterium tumefaciens-mediated immature embryo transformation was used to produce transgenic maize. Immature embryo of Hi II genotype were co-cultivated with strains Agrobacterium tumefaciens (C58C1) containing the binary vectors (pPTN290) carrying with Ubiquitin promoter-GUS gene as reporter gene and NOS promoter-nptll gene conferring resistance to paromomycin as selective agent. Seven embryogenic callus lines transformed showed the resistance in paromomycin antibiotics. Histochemical GUS assay showed that 7 individual lines transformed with the GUS gene were positive response among the transformants. Southern blot analysis revealed that the nptll gene segregated and expressed in their progeny.

• Radiation Oncology Journal
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• v.17 no.4
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• pp.299-306
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• 1999

Purpose : The human genetic disorder ataxia-telangiectasia (AT) is a multisystem disease characterized by extreme radiosensitivity. The recent identification of the gene mutated in AT, ATM, and the demonstration that it encodes a homologous domain of phosphatidylinositol 3-kinase (PI3-K), the catalytic subunit of an enzyme involved in transmitting signals from the cell surface to the nucleus, provide support for a role of this gene in signal transduction. Although ionizing radiation was known to induce c-fos transcription, nothing is known about how ATM or PKCI mediated signal transduction pathway modulates the c-fos gene transcription and gene expression. Here we have studied the effect of PKCI on radiation sensitivity and c-fos transcription in normal and AT cells. Materials and Methods: Normal (LM217) and AT (AT5BIVA) cells were transfected with PKCI expression plasmid and the overexpression and integration of PKCI was evaluated by northern blotting and polymerase chain reaction, respectively. 5 Gy of radiation was exposed to LM and AT cells transfected with PKCI expression plasmid and cells were harvested 48 hours after radiation and investigated apoptosis with TUNEL method. The c-fos transcription activity was studied by performing CAT assay of reporter gene after transfection of c-fos CAT plasmid into AT and LM cells. Results: Our results demonstrate for the first time a role of PKCI on the radiation sensitivity and c-fos expression in LM and AT cells. PKCI increased radiation induced apoptosis in LM cells but reduced apoptosis in AT cells. The basal c-fos transcription activity is 70 times lower in AT cells than that in LM cells. The c-fos transcription activity was repressed by overexpression of PKCI in LM cells but not in AT cells. After induction of c-fos by Ras protein, overexpression of PKCI repressed c-fos transcription in LM cells but not in AT cells Conclusion: Overexpression of PKCI increased radiation sensitivity and repressed c-fos transcription in LM cells but not in AT cells. The results may be a. reason of increased radiation sensitivity of AT cells. PKCI may be involved in an ionizing radiation induced signal transduction pathway responsible for radiation sensitivity and c-fos transcription. The data also provided evidence for novel transcriptional difference between LM and AT cells.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.10
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• pp.1383-1391
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• 2016

Bovine embryonic stem cells have potential for use in research, such as transgenic cattle generation and the study of developmental gene regulation. The Nanog may play a critical role in maintenance of the undifferentiated state of embryonic stem cells in the bovine, as in murine and human. Nevertheless, efforts to study the bovine Nanog for pluripotency-maintaining factors have been insufficient. In this study, in order to understand the mechanisms of transcriptional regulation of the bovine Nanog, the 5'-flanking region of the Nanog was isolated from ear cells of Hanwoo. Results of transient transfection using a luciferase reporter gene under the control of serially deleted 5'-flanking sequences revealed that the -134 to -19 region contained the positive regulatory sequences for the transcription of the bovine Nanog. Results from mutagenesis studies demonstrated that the Sp1-binding site that is located in the proximal promoter region plays an important role in transcriptional activity of the bovine Nanog promoter. The electrophoretic mobility shift assay with the Sp1 specific antibody confirmed the specific binding of Sp1 transcription factor to this site. In addition, significant inhibition of Nanog promoter activity by the Sp1 mutant was observed in murine embryonic stem cells. Furthermore, chromatin-immunoprecipitation assay with the Sp1 specific antibody confirmed the specific binding of Sp1 transcription factor to this site. These results suggest that Sp1 is an essential regulatory factor for bovine Nanog transcriptional activity.

• The Journal of Korean Medicine
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• v.32 no.3
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• pp.35-43
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• 2011

Objectives: This study was performed to screen target-specific inhibitors of ${\beta}$-catenin/TCF signaling whose functional activation plays an important role in early events in carcinogenesis. Methods: To investigate the activation or suppression of ${\beta}$-catenin/TCF transcription, we established a transiently transfected cell line with a constitutively active ${\beta}$-catenin mutant gene whose product is not degraded. This cell line was also co-transfected with luciferase reporter gene constructs containing either an optimized (TOPflash) or mutant (FOPflash) TCF-binding element. We investigated cytotoxic effects using a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt (MTS) assay. To find effective inhibitors of ${\beta}$-catenin/TCF signaling from medicinal herbs, the crude extracts of 99 types of medicinal herbs were screened using a luciferase assay system in HEK-293 and SH-SY5y cells. Results: At a concentration of $50{\mu}g$/ml, extracts of Angelica koreanae radix, Cannabis sativa semen, Ephedrae intermedia Schrenk radix, and Vitis rotundifolia fruit showed the following inhibitory effects on ${\beta}$-catenin/TCF signaling: $40{\pm}5.6%$, $23{\pm}6.1%$, $8{\pm}5.1%$, and $22{\pm}9.8%$ in ${\beta}$-catenin-activated HEK-293 cells and $9{\pm}4.7%$, $39{\pm}8.1%$, $39{\pm}6.4%$, and $42{\pm}10.1%$ in ${\beta}$-catenin-activated SH-SY5y cells, respectively. Crude extracts of E. radix were isolated by silica gel column chromatography, and two non-polar fractions of these extracts showed inhibitory effects on ${\beta}$-catenin/TCF signaling. Conclusions: In this study, we established a transiently transfected cell line as a screening system and found that various medicinal herb extracts had inhibitory effects on ${\beta}$signaling.

• Journal of Ginseng Research
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• v.42 no.4
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• pp.496-503
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• 2018

Background: Korean ginseng (Panax ginseng) plays an anti-inflammatory role in a variety of inflammatory diseases such as gastritis, hepatitis, and colitis. However, inflammation-regulatory activity of the calyx of the P. ginseng berry has not been thoroughly evaluated. To understand whether the calyx portion of the P. ginseng berry is able to ameliorate inflammatory processes, an ethanolic extract of P. ginseng berry calyx (Pg-C-EE) was prepared, and lipopolysaccharide-activated macrophages and HEK293 cells transfected with inflammation-regulatory proteins were used to test the anti-inflammatory action of Pg-C-EE. Methods: The ginsenoside contents of Pg-C-EE were analyzed by HPLC. Suppressive activity of Pg-C-EE on NO production, inflammatory gene expression, transcriptional activation, and inflammation signaling events were examined using the Griess assay, reverse transcription-polymerization chain reaction, luciferase activity reporter gene assay, and immunoblotting analysis. Results: Pg-C-EE reduced NO production and diminished mRNA expression of inflammatory genes such as cyclooxygenase-2, inducible NO synthase, and tumor necrosis factor-${\alpha}$ in a dose-dependent manner. This extract suppressed luciferase activity induced only by nuclear factor-${\kappa}B$. Interestingly, immunoblotting analysis results demonstrated that Pg-C-EE reduced the activities of protein kinase B (AKT)1 and AKT2. Conclusion: These results suggest that Pg-C-EE may have nuclear-factor-${\kappa}B$-targeted anti-inflammatory properties through suppression of AKT. The calyx of the P. ginseng berry is an underused part of the ginseng plant, and development of calyx-derived extracts may be useful for treatment of inflammatory diseases.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.780-803
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• 2003

Exposure of skin cells, particularly keratinocytes to various nuclear factor-kappaB ($\textrm{NF}_{-{\kappa}}\textrm{B}$) activators [e.g. tumor necrosis factor-$\alpha$, interleukin-1, lipopolysaccharides, and ultraviolet light] leads to phosphorylation and degradation of the inhibitory protein, $\textrm{I}_{{\kappa}}\textrm{B}$. Liberated $\textrm{NF}_{-{\kappa}}\textrm{B}$ is translocated into the nucleus where it can change or alter expression of target genes, resulting in the secretion of extracellular signaling molecules including melanotrophic factors affecting melanocyte. In order to demonstrate the possible role of $\textrm{NF}_{-{\kappa}}\textrm{B}$ activation on the synthesis of melanotrophic factors from the keratinocytes, the activities of $\textrm{NF}_{-{\kappa}}\textrm{B}$ induced by melanogenic inhibitors (MIs) were determined in human HaCaT keratinocytes transfected with $\textrm{pNF}_{-{\kappa}}\textrm{B}$-SEAP-NPT plasmid. Transfectant cells released the secretory alkaline phosphatase (SEAP) as a transcription reporter in response to the $\textrm{NF}_{-{\kappa}}\textrm{B}$ activity and contain the neomycin phosphotransferase (NPT) gene for the dominant selection marker for geneticin resistance. MIs such as niacinamide, kojic acid, hydroquinone, resorcinol, arbutin, and glycolic acid were preincubated with transfectant HaCaT cells for 3 h and then ultraviolet B (UVB) was irradiated. $\textrm{NF}_{-{\kappa}}\textrm{B}$ activation was measured with the SEAP reporter gene assay using a fluorescence detection method. Of the Mis tested, kojic acid ($IC_{50}$/ = 60 $\mu$M) was found to be the most potent inhibitor of UVB-upregulating $\textrm{NF}_{-{\kappa}}\textrm{B}$ activation in transfectant HaCaT cells, which is followed by niacinamide ($IC_{50}$/= 540 $\mu$M). Pretreatment of the transfectant HaCaT cells with the Mis, especially kojic acid and niacinamide, effectively lowered $\textrm{NF}_{-{\kappa}}\textrm{B}$ binding measured by electrophoretic mobility shift assay. Furthermore, these two inhibitors remarkably reduced the secretion level of IL-6, one of melanotrophic factors, triggered by UV-radiation of the HaCaT cells. These observations suggest that Mis working at the in vivo level might act partially through the modulation of the synthesis of melanotrophic factors in keratinocyte.

• Molecules and Cells
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• v.37 no.12
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• pp.873-880
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• 2014

In our previous study, miRNA-183, a miRNA in the miR-96-182-183 cluster, was significantly over-expressed in esophageal squamous cell carcinoma (ESCC). In the present study, we explored the oncogenic roles of miR-183 in ESCC by gain and loss of function analysis in an esophageal cancer cell line (EC9706). Genome-wide mRNA micro-array was applied to determine the genes that were regulated directly or indirectly by miR-183. 3'UTR luciferase reporter assay, RT-PCR, and Western blot were conducted to verify the target gene of miR-183. Cell culture results showed that miR-183 inhibited apoptosis (p < 0.05), enhanced cell proliferation (p < 0.05), and accelerated G1/S transition (p < 0.05). Moreover, the inhibitory effect of miR-183 on apoptosis was rescued when miR-183 was suppressed via miR-183 inhibitor (p < 0.05). Western blot analysis showed that the expression of programmed cell death 4 (PDCD4), which was predicted as the target gene of miR-183 by microarray profiling and bioinformatics predictions, decreased when miR-183 was over-expressed. The 3'UTR luciferase reporter assay confirmed that miR-183 directly regulated PDCD4 by binding to sequences in the 3'UTR of PDCD4. Pearson correlation analysis further confirmed the significant negative correlation between miR-183 and PDCD4 in both cell lines and in ESCC patients. Our data suggest that miR-183 might play an oncogenic role in ESCC by regulating PDCD4 expression.