• 한국식품영양학회지
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• 제33권3호
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• pp.309-316
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• 2020

In this study, we investigated the protective effects of Ulva lactuca methanol extracts against ultraviolet B (UVB)-induced DNA damage in HaCaT cells. First, the contents of general and antioxidative nutrient contents of Ulva lactuca were measured. The moisture, carbohydrate, crude protein, crude fat and ash were 14.01%, 44.80%, 23.19%, 3.10% and 14.90%, respectively. Magnesium that acts as DNA repair enzyme cofactor was the most abundant mineral followed by Ca, P and Fe. The total phenolic and anthocyanoside contents of Ulva lactuca were 2.69 mg/g and 0.13 mg/g, respectively. Cells treated with Ulva lactuca methanol extracts for 24 hours post UVB exposure increased cell viability in a concentration-dependent manner compared to the non-treated control. Also, Ulva lactuca methanol extracts decreased the levels of UVB-induced DNA damage such as cyclobutane pyrimidine dimer and DNA damage response (DDR) proteins such as p-p53 and p21. These results suggest that Ulva lactuca methanol extracts comprising physiological active substances such as Mg, polyphenols and anthocyanosides promote DNA repair by regulating genes related with DDR.

• Molecules and Cells
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• 제40권2호
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• pp.143-150
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• 2017

Homologous recombination (HR) is necessary for maintenance of genomic integrity and prevention of various mutations in tumor suppressor genes and proto-oncogenes. Rad51 and Rad54 are key HR factors that cope with replication stress and DNA breaks in eukaryotes. Rad51 binds to single-stranded DNA (ssDNA) to form the presynaptic filament that promotes a homology search and DNA strand exchange, and Rad54 stimulates the strand-pairing function of Rad51. Here, we studied the molecular dynamics of Rad51 and Rad54 during the cell cycle of HeLa cells. These cells constitutively express Rad51 and Rad54 throughout the entire cell cycle, and the formation of foci immediately increased in response to various types of DNA damage and replication stress, except for caffeine, which suppressed the Rad51-dependent HR pathway. Depletion of Rad51 caused severe defects in response to postreplicative stress. Accordingly, HeLa cells were arrested at the G2-M transition although a small amount of Rad51 was steadily maintained in HeLa cells. Our results suggest that cell cycle progression and proliferation of HeLa cells can be tightly controlled by the abundance of HR proteins, which are essential for the rapid response to postreplicative stress and DNA damage stress.

• Applied Biological Chemistry
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• 제48권2호
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• pp.155-160
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• 2005

본 연구에서는 매우 낮은 음의 산화환원전위를 나타내는 환원전리수가 paraquat에 의한 사람 임파구 DNA의 손상에 미치는 영향을 Comet assay를 사용하여 조사하였다. 환원전리수 처리에 의해서 paraquat에 의해 산화적으로 손상된 DNA가 회복되는 정도를 손상된 DNA로 인한 꼬리부분의 형광광도의 %비율로 나타내었다. Comet assay는 개별 세포의 DNA의 산화적 손상을 측정하는데 널리 사용되고 있다. 사람 임파구에 다양한 농도의 paraquat을 $37^{\circ}C$에서 30분간 처리한 후, 환원전리수를 첨가하여 30분간 반응시켰다. 그 결과 paraquat에 의한 임파구 DNA의 손상은 paraquart 농도증가에 의존적으로 증가하였다. 그러나 환원전리수를 처리한 결과 DNA의 산화적 손상이 paraquat 미처리 대조군 수준으로 거의 다 복구되었다.

• 대한한의학회지
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• 제27권4호
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• pp.162-173
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• 2006

The water-extracts of Scutellaria barbata Don (SBDE) were isolated from Chinese medicinal plant sources. The extracts showed strong growth-inhibitory activity and cancer chemopreventive activity on the growth and DNA incorporation of MG63 human osteosarcoma and K562 human leukemia cell lines. The growth of human cancer cells was inhibited in the presence of the extracts (20, 50 and 100 ${\mu}$g/ml), and the effects were concentration-dependent and incubation time-dependent up to 8 days. When 50 ${\mu}$g/ml of the extracts was added to the media of MG63 and K562, cell growth after 8 days or 6 days of incubation was retarded by 93.2 to 97.3% of the control group. Morphological changes of MG63 and K562 cell lines were observed. As the concentration of the extracts increased up to 50 ${\mu}$g/ml, degree of cell aggregation decreased. Moreover, the DNA incorporation of the cells which were labeled with [3H] thymidine was significantly reduced after 3 days of incubation at $37^{\circ}C$ with the extract. Therefore, it is suggested that the extract is highly effective on inhibition of cancer cell growth. The extract also inhibited gene expression of IGF-II in transcriptional level. Since IGF-II works as a mitogenic effector on MG63 and K562 cell lines, these results suggest that the growth inhibition is in part mediated through the inhibition of IGF-II gene expression.

• BMB Reports
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• 제43권12호
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• pp.807-812
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• 2010

$NF{\kappa}B$ and ZAS3 are transcription factors that control important cellular processes including immunity, cell survival and apoptosis. Although both proteins bind the ${\kappa}B$-motif, they produce opposite physiological consequences; $NF{\kappa}B$ activates transcription, promotes cell growth and is often found to be constitutively expressed in cancer cells, while ZAS3 generally represses transcription, inhibits cell proliferation and is downregulated in some cancers. Here, we show that ZAS3 inhibits $NF{\kappa}B$-dependent transcription by competing with $NF{\kappa}B$ for the ${\kappa}B$-motif. Transient transfection studies show that N-terminal 645 amino acids is sufficient to repress transcription activated by $NF{\kappa}B$, and that the identical region also possesses intrinsic repression activity to inhibit basal transcription from a promoter. Finally, in vitro DNA-protein interaction analysis shows that ZAS3 is able to displace $NF{\kappa}B$ by competing with $NF{\kappa}B$ for the ${\kappa}B$-motif. It is conceivable that ZAS3 has therapeutic potential for controlling aberrant activation of $NF{\kappa}B$ in various diseases.

• Journal of Microbiology and Biotechnology
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• 제3권1호
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• pp.1-5
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• 1993

The gene for mannose enzyme II of phosphoenolpyruvate-dependent phosphotransferase system from Corynebacterium glutamicum KCTC 1445 was cloned into Escherichia coli ZSC113 using plasmid pBR 322. The recombinant plasmid, designated pCTS3, contained 2.2 kb DNA fragment, and the physical map of the cloned DNA fragment was determined. The E. coli ptsM ptsG mutant transformed with pCTS3 restored glucose and mannose fermentation ability, and grew well on these sugars as the sole carbon source in the minimal medium. The transform ant harboring pCTS3 showed a PTS-mediated repression of growth on maltose by mannose analogue, 2-deoxyglucose. The specificity of the response to 2DG therefore indicates that the cloned DNA fragment carries mannose enzyme II gene.

• BMB Reports
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• 제29권6호
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• pp.513-518
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• 1996

A soluble protein from Saccharomyces cerevisiae specifically provides protection against a thiolcontaining oxidation system but not against an oxidation system without thiol. This 25-kDa protein was thus named thiol-dependent protector protein (TPP). The role of TPP in the cellular defense against oxidative stress was investigated in Escherichia coli containing an expression vector with a yeast genomic DNA fragment that encodes TPP (strain YP) and a mutant in which the catalytically essential amino acid in the active site of TPP (Cys-47) has been replaced with alanine by site-directed mutagenesis (strain YPC47A). There was a distinct difference between these two strains in regard to viability, modulation of activities of superoxide dismutase and catalase, and the oxidative damage of DNA upon exposure to menadione. These results suggest that TPP may play a direct role in the cellular defense against oxidative stress by functioning as an antioxidant protein.

• Food Science and Biotechnology
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• 제17권2호
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• pp.343-348
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• 2008

In this study, antioxidant activity of methanol extract of Glycyrrhiza uralensis Fisch (GUE) against $H_2O_2$-induced DNA damage in human leucocytcs and cell death in PC12 cells was determined. The effect of GUE on $H_2O_2$-induced DNA damage in human leucocytcs was evaluated by the comet assay, where GUE ($1-50\;{\mu}g/mL$) was a dose dependent inhibitor of DNA damage induced by $H_2O_2$. The protective effect of GUE against $H_2O_2$-induced damage on PC12 cells was investigated by MTT reduction assay and lactate dehydrogenase release assay. A marked reduction in cell survival induced by $H_2O_2$ was significantly prevented by $1-50\;{\mu}g/mL$ of GUE. The enzyme activity of caspase-3 was elevated in $H_2O_2$-treated PC12 cells, while preincubation with GUE for 30 min inhibited $H_2O_2$-induced caspase-3 activation in a dose-dependent manner. In conclusion, GUE ameliorates $H_2O_2$-induced DNA damage in human leucocytes and has neuroprotective effect by preventing cell death in PC12 cell, suggesting that GU may be a potential candidate for novel therapeutic agents for neuronal diseases associated with oxidative stress.

• 대한한의학회지
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• 제20권1호
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• pp.91-105
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• 1999

The effects of Yinjin and Yinjinsaryongsangagambang on a DNA damaging agent, etoposide-induced apoptosis, cell viability, cell cycle progression, and mRNA expression of apoptosis-related genes of human hepatocyte cell line HepG2 were investigated using tryphan blue exclusion assay, MTT assay, flow cytometry, immunocytometric analysis of PCNA, and quantitative RT-PCR analysis. MTT assay showed that Yinjin and Yinjinsaryongsangagambang increases cellular viability of HepG2 cells in a dosage-dependent manner. Stimulation of cell cycle progression by Yinjin or Yinjinsaryongsangagambang was detected by flow cytometric analysis of the DNA content and immunocytometric analysis of PCNA expression. A significant reduction of a DNA-damaging agent, etoposide-induced apoptosis were found in both Yinjin and Yinjinsaryongsangagambang-treated cells in dosage-dependent manner. In overall, 3-fold reduction of apoptosis was recognized in $10.0\;{\mu}g/ml$ of Yinjin or Yinjinsaryongsangagambang-treated cells compared to untreated cells. Although the difference is not significant, Yinjinsaryongsangagambang showed slightly higher effect on the inhibition of apoptosis than Yinjin. From flow cytometric analysis of apoptosis, while 39.9% of untreated cells showed etoposide-induced apoptotic cell death, only 19.6% or 17.4% of Yinjin or Yinjinsaryongsangagambang-treated cells were fond at apoptotic sub G1 phase, respectively. Interestingly, strong induction of Gadd45-mRNA was observed from Yinjin or Yinjinsaryongsangagambang-treated cells. However, no changes in expression levels of p53 and Waf1 were detected, demonstrating that induction of Gadd45 mRNA expression by Yinjin or Yinjinsaryongsangagambang occurs by p53-independent mechanism. Marked mRNA inductions of two apoptosis-inhibiting genes, Bcl-2 and Bcl- XL, were found in both Yinjin or Yinjinsaryongsangagambang-treated HepG2 cells while no changes was detected in expression levels of an apoptosis-promoting gene, Bax.

• Journal of Nutrition and Health
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• 제54권4호
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• pp.335-341
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• 2021

Purpose: Muscle mitochondria play a key role in regulating fatty acid and glucose metabolism. Dysfunction of muscle mitochondria is associated with metabolic diseases such as obesity and type 2 diabetes. Isorhamnetin (ISOR), also known as 3-O-methylquercetin, a quercetin metabolite, is a naturally occurring flavonoid in many plants. This study evaluated the effects of ISOR on the regulation of the mitochondrial function of C2C12 muscle cells. Methods: C2C12 muscle cells were differentiated for 5 days, and then treated in various concentrations of ISOR. Cytotoxicity was determined by assessing cell viability using the water-soluble tetrazolium salt-8 assay principle at different concentrations of ISOR and time points. Levels of the mitochondrial DNA (mtDNA) content and gene expression were measured by quantitative real-time polymerase chain reaction. The citrate synthase (CS) activity was quantified by the enzymatic method. Results: ISOR at a concentration of 10 µM did not show any cytotoxic effects. ISOR increased the mtDNA copy number in a time- or dose-dependent manner. The messenger RNA levels of genes involved in mitochondrial function, such as peroxisome proliferator-activated receptor-γ coactivator-1α, and uncoupling protein 3 were significantly stimulated by the ISOR treatment. The CS activity was also significantly increased in a time- or dose-dependent manner. Conclusion: These results suggest that ISOR enhances the regulation of mitochondrial function, which was at least partially mediated via the stimulation of the mtDNA replication, mitochondrial gene expression, and CS activity in C2C12 muscle cells. Therefore, ISOR may be useful as a potential food ingredient to prevent metabolic diseases-associated muscle mitochondrial dysfunction.