• Biomolecules & Therapeutics
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• 제15권3호
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• pp.137-144
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• 2007

Although lovastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMGCoA) reductase, has been shown to have anti-cancer actions, the effect on human hepatoma cells was not investigated. Moreover, the exact mechanism of this action is not fully understood. In this study we investigated the mechanism by which lovastatin induces apoptosis using HepG2 human hepatoblastoma cells. Lovastatin induced apoptotic cell death in a dose-dependent manner in the cells, assessed by the flow cytometric analysis. Treatment with mevalonic acid, a precursor of cholesterol, did not significantly suppress the lovastatin-induced apoptosis. Lovastatin induced a rapid and sustained increase in intracellular $Ca^{2+}$ concentration. Treatment with EGTA, an extracellular $Ca^{2+}$ chelator did not significantly alter the lovastatin-induced intracellular $Ca^{2+}$ increase and apoptosis, whereas intracellular $Ca^{2+}$ reduction with BAPTA/AM and intracellular $Ca^{2+}$ release blockers (dantrolene and TMB-8) completely blocked these actions of lovastatin. In addition, the lovastatin-induced apoptosis was significantly reduced by a calpain inhibitor, a broad spectrum caspase inhibitor z-VAD-fmk and inhibitors specific for caspase-9 and caspase-3 (z-LEHD-fmk and z-DEVD-fmk, respectively), but not by an inhibitor specific for caspase-8 (z-IETD-fmk). Collectively, these results suggest that lovastatin induced apoptosis of HepG2 hepatoma cells through intracellular $Ca^{2+}$ release and calpain activation, leading to triggering mitochondrial apoptotic pathway. These results further suggest that lovastatin may be valuable for the therapeutic management of human hepatoma.

• 한국식품영양과학회지
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• 제32권6호
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• pp.931-936
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• 2003

본 연구에서는 항암효과를 가진 성분을 포함하여 여러 다양한 생리활성 물질을 함유하고 있을 것으로 기대되는 노루궁뎅이 버섯(Hericium erinaceus)을 이용하여 암세포 성장저해효과와 세포주기 조절자인 cyclin 단백질의 발현에 미치는 영향을 조사하였다. 노루궁뎅이 버섯의 메탄을 추출물과 그 분획물들의 사람의 암세포주인 HT29와 HepG2에 대한 성장 저해 효과를 MTT assay로 검토한 결과 노루궁뎅이 버섯의 메탄을 추출물과 헥산, 클로로포름 그리고 에틸아세테이트 분획물들이 높은 암세포 성장 저해 효과를 나타내었으며 농도 의존적인 경향을 보였다. 그러나 사람의 정상 간세포인 Chang cell에서는 세포독성이 나타나지 않았다 그리고 노루궁뎅이 버섯 메탄올추출물이 간암 세포주인 HepG2의 cyclin 단백질 발현에 미치는 영향을 조사한 결과 노루궁뎅이 버섯 메탄을 추출물이 cyclin A와 D 단백질 발현을 다소 감소시켰으며 특히 cyclin B1에 대한 효과가 더욱 크게 나타나 1 mg/mL 농도에서 48시간 처리 하였을 때 대조군에 비해 30% 정도까지 단백질 발현이 감소하였다. 이러한 결과로 노루궁뎅이 버섯은 세포주기 중 G2기에서 M기로의 전환에 관여하는 cyclin B1 단백질의 발현을 크게 감소시키므로 세포주기 진행을 차단시켜 간암세포의 증식을 억제시키는 것으로 사료된다.

• Toxicological Research
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• 제23권1호
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• pp.25-31
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• 2007

To evaluate the protective effect of Houttuynia cordata on hydrogen peroxide-induced oxidative DNA damage in HepG2 cell line, we used an alkaline single-cell gel electrophoresis (SCGE; comet assay). The DNA damage was analyzed by tail moment (TM) and tail length (TL), which used markers of DNA strand breaks in SCGE. The $100{\mu}g/ml$ of methanolic extract of Houttuynia cordata root showed significant protective effects (p < 0.01) against hydrogen peroxide-induced DNA damage in HepG2 cells and increased cell viability against hydrogen peroxide. The results of this study indicate that Houttuynia cordata root methanol extract acts as a potential antioxidant, and exhibits potential anticancer properties, which may provide a clue to find applications in new pharmaceuticals for oxidative stability.

• 한국식품영양과학회지
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• 제37권10호
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• pp.1238-1243
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• 2008

잔대 뿌리는 우리나라에서 예로부터 민간약으로 이용되어 오고 있다. 본 연구에서는 인간 간세포인 HepG2에 잔대 뿌리의 에틸아세테이트 추출물을 처리했을 때 sodium nitroprusside(SNP)에 의해 유도된 세포 독성 및 항산화 유전자 발현에 미치는 영향력을 알아보았다. 먼저, 잔대 에틸아세테이트 추출물이 NO에 의해 유도된 세포 사멸을 저해할 수 있는지를 알아보기 위하여 HepG2 세포에 잔대 에틸아세테이트 추출물(각각 50과 100 $\mu$g/mL)을 24시간 먼저 처리한 후 세포내에서 NO을 생성시킬 수 있는 0.5 mM SNP를 처리하였다. NO에 의한 세포독성이 에틸아세테이트 추출물에 의해 저해되었다는 것을 mitochondrial dehydrogenase 활성을 알아보는 MTT assay를 실시하여 알아보았다. 더하여 우리는 잔대 에틸아세테이트 추출물이 세포내 항산화 방어 시스템인 Cu,Zn superoxide dismutase(SOD 1), Mn SOD(SOD 2), glutathione peroxidase(GPx), catalase와 glutathione metabolism과 관련되어져 있는 glutathione reductase(GR), $\gamma$-glutamyl-cystein synthetase(GCS), glutathione-S-transferase(GST), $\gamma$-glutamyltranspeptidase($\gamma$-GT), glucose-6-phosphate dehydrogenase(G6PD)의 mRNA 발현에 미치는 영향을 RT-PCR로 알아보았다. CAT, GCS 그리고 G6PD mRNA 수준이 잔대 에틸아세테이트 추출물 처리 후 증가하였으나, SOD 1, SOD 2, GPx, GST 그리고 $\gamma$-GT mRNA 수준은 변화지 않았다. 따라서 잔대 에틸아세테이트 추출물이 간접적 항산화 효과가 있고, 이들 효과는 아마 CAT, GCS, GR 그리고 G6PD 유전자 발현 증가에 의한 것이라고 추정되었다.

• 한국식품영양과학회지
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• 제42권3호
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• pp.342-347
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• 2013

마늘에 적용가능 한 유산균을 찾기 위해 마늘 이외의 배지 성분 없이 각각의 유산균을 배양하고 유산균발효마늘 추출물을 제조하여 각각의 추출물의 유기황화합물을 분석하고 항산화효과 및 알코올 유발 세포독성에 미치는 영향을 알아보았다. 마늘멸균액을 배지로 유산균을 48시간 배양하였을 때 L. plantarum이 가장 잘 자랐으며 유산균발효마늘 추출물 중 항산화활성 등의 효능이 있는 것으로 알려진 SAC 함량은 L. plantarum의 발효물과 P. pentosaceus의 발효물이 각각 3.619 mg/g과 3.234 mg/g으로 가장 많은 것으로 나타났다(p<0.05). 그리고 SAC, SEC, SMC의 경우 유산균발효 마늘 추출물들이 마늘 추출물에 비해 높았으나 alliin의 경우 유산균발효마늘 추출물들이 마늘 추출물에 비하여 낮은 것으로 나타났다(p<0.05). 또한 cycloalliin의 경우 마늘 추출물과 유산균발효마늘 추출물들 간의 함량 차이는 없었다(p<0.05). 모든 유산균발효마늘 추출물이 농도 의존적으로 항산화활성이 높은 것으로 나타났으며, L. plantarum의 발효물과 P. pentosaceus의 발효물이 5.0 mg/g의 농도에서 90% 이상의 높은 전자공여능을 효과를 나타냈다. 유산균발효마늘 추출물들이 $100{\mu}g/mL$의 농도까지 CYP2E1 transfected HepG2 세포주에 영향을 주지 않았으며, 각각의 유산균발효 마늘 추출물을 알코올에 의해 손상된 CYP2E1 transfected HepG2 세포의 보호효과를 확인한 결과 에탄올과 시료를 6일간 처리한 경우에 FGPP와 FGLP가 각각 92.60%와 92.23%로 유의적으로 가장 높은 세포생존율을 보였다(p<0.05).

• 한국약용작물학회지
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• 제17권2호
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• pp.133-138
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• 2009

Nelumbo nucifera (lotus) is known to be a useful medicinal plant and leaf extract contains several flavonoids and alkaloids. To analyze the effect of Nelumbo nucifera leaves extract (NNL) on the HBsAg production, we treated NNL on HepG2.2.15 cells which contain the hepatitis B viral genome and secrete surface antigen into media. NNL suppressed the production of hepatitis B surface antigen as a dose-dependent manner. To analyze the effect of NNL on HBV DNA replication, PCR analysis was performed. NNL was not affected the HBV DNA replication and HBsAg mRNA expression. To understand the effect of NNL on the production of HBsAg, we carried out the analysis of lipid-metabolizing gene expression using one-step RT-PCR. NNL reduced the gene expression of FASN and SREBP2 and increased the expression of LDLR. Triglyceride content of HepG2.2.15 cells was not decreased by treatment of NNL. This result suggests a possibility that NNL may have an effect for the inhibition of hepatitis B surface antigen by modulation of lipid and cholesterol metabolism.

• Toxicological Research
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• 제19권3호
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• pp.235-240
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• 2003

The modification of CYP2E1 activity is of considerable interest because of its role in the metabolic activation of a variety of toxic chemicals. In the present studies, the time-course of changes in human CYP2E1 activities was determined after treatment with ethanol, glycerol, 4-methylpyrazole or isoniazid using intact HepG2 cells transfected by human CYP2E1. Hydroxylation of chlorzoxazone was chosen for the measurement of CYP2E1 activity. CYP2E1 protein levels were increased upon cultivation of cells in the presence of ethanol, glycerol, 4-methylpyrazole or isoniazid for 24 hr. After 24 hr cultivation, ethanol or glycerol increased CYP2E1 activities, whereas 4-methylpyrazole or isoniazid inhibited. This different effect of the chemical inducers on CYP2E1 activi-ties persisted to subsequent 24 hr. Competitive inhibition study suggested that 4-methylpyrazole or isoniazid has stronger binding affinity to CYP2E1 than ethanol or glycerol. These results demonstrate that different binding affinity of the chemical inducers to the active site of CYP2E1 plays important role in determining real CYP2E1 activity in intact cells after treatment with the chemical inducers. Present study would be helpful in precise understanding of human CYP2E1-mediated toxicity.

• 한국환경보건학회지
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• 제29권3호
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• pp.9-15
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• 2003

The modification of CYP2El activity is a matter of considerable interest because of its role in the metabolic activation of a variety of environmental toxicants. In the present study, the time-course of changes in human CYP2El activities was determined following treatment with solvents (acetone, dimethylsulphoxide or pyridine) using intact HepG2 cells transfected by human CYP2El. Hydroxylation of chlorzoxazone was used for the measurement of CYP2El activity. CYP2E1 protein level was increased upon cultivation of cells in the presence of the solvents for 24 hr. Determination of CYP2El activities after 24 ht cultivation with the solvents demonstrated that acetone or dimethylsulphoxide increased, whereas pyridine inhibited the activities. This differential effect of the solvents on CYP2El activities persisted to subsequent 24 ht. Competitive inhibition study suggested that pyridine has stronger binding affinity to CYP2E1 than acetone or dimethylsulphoxide. These results demonstrate that different binding affinity of the solvents to CYP2El plays important role in determining real CYP2El activity in intact cells after exposure to the solvents. Present study would be helpful in precise understanding of human CYP2El-mediated toxicity.

• Nutrition Research and Practice
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• 제8권2호
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• pp.125-131
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• 2014

BACKGROUND/OBJECTIVES: The objective of this study was to evaluate the protective effect of black rice extract (BRE) on tert-butyl hydroperoxide (TBHP)-induced oxidative injury in HepG2 cells. MATERIALS/METHODS: Methanolic extract from black rice was evaluated for the protective effect on TBHP-induced oxidative injury in HepG2 cells. Several biomarkers that modulate cell survival and death including reactive oxygen species (ROS), caspase-3 activity, and related cellular kinases were determined. RESULTS: TBHP induced cell death and apoptosis by a rapid increase in ROS generation and caspase-3 activity. Moreover, TBHP-induced oxidative stress resulted in a transient ERK1/2 activation and a sustained increase of JNK1/2 activation. While, BRE pretreatment protects the cells against oxidative stress by reducing cell death, caspase-3 activity, and ROS generation and also by preventing ERKs deactivation and the prolonged JNKs activation. Moreover, pretreatment of BRE increased the activation of ERKs and Akt which are pro-survival signal proteins. However, this effect was blunted in the presence of ERKs and Akt inhibitors. CONCLUSIONS: These results suggest that activation of ERKs and Akt pathway might be involved in the cytoprotective effect of BRE against oxidative stress. Our findings provide new insights into the cytoprotective effects and its possible mechanism of black rice against oxidative stress.

• Asian Pacific Journal of Cancer Prevention
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• 제15권6호
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• pp.2565-2570
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• 2014

H19 is an imprinted oncofetal gene, and loss of imprinting at the H19 locus results in over-expression of H19 in cancers. Aflatoxin B1(AFB1) is regarded as one of the most dangerous carcinogens. Exposure to AFB1 would most easily increase susceptibility to diseases such as hepatocellular carcinoma(HCC) but any possible relationship between AFB1 and H19 is not clear. In present study, we found that AFB1 could up-regulate the expression of H19 and promote cell growth and invasion by hepatocellular carcinoma HepG2 cells. Knocking down H19 RNA co ld reverse the effects of AFB1 on cell growth and invasion. In addition, AFB1 induced the expression of E2F1 and its knock-down could down-regulate H19 expression and suppress cell growth and invasion in hepatocellular carcinoma HepG2 cells. Furthermore, E2F1 over-expression could up-regulate H19 expression and promote cell growth and invasion, with binding to the H19 promoter being demonstrated by chromatin immunoprecipitation assays (ChIP). In summary, our results suggested that aflatoxin B1could promote cell growth and invasion in hepatocellular carcinoma HepG2 cells through actions on H19 and E2F1.