• 한국식품위생안전성학회지
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• 제14권1호
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• pp.60-66
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• 1999

Diethylnitrosamine (DEN) is known as a potential hepatic carcinogen by single administration. This study was designed to measure the effects of DEN-induced cell damage on the triglyceride and cholesterol concentration in the liver, excluding dietary effects. Fertilized chicken eggs, 10 days before hatching, were randomly divided into three groups (n=20) and each egg was injected 10 ${mu}ell$ of corn oil (vehicle control), 5 $\mu\textrm{g}$ of DEN/10 ${mu}ell$ of DEN/10 ${mu}ell$ into yolk via air sac. After 48 hr and 96 hr incubation, the damage of the chick-embryo liver cell was investigated by electron microscopy and by measuring the concentration of lipid components (total cholesterol, free cholesterol, phospholipid and triglyceride). For eggs administered 10 $\mu\textrm{g}$ of DEN and incuvated 96 hr, in hepatocyte, the nucleus membrane was roughed, the size of nucleolus was apparently increased and euchromatin was accumulated. Mitochondria were condensed and cristae, located mitochondiral inner membrane, were obscured. Additionally, the leaves of triglyceride and cholesterol classes were significantly increased depend on the amount treated with 10 $\mu\textrm{g}$ DEN at 96 hr, but phospholipids component of cell membrane, were decreased with significance. As a conclusion, carcinogen induced hepatic lesion was correlated with the changes in lipid component of liver.

• 대한수의학회지
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• 제29권1호
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• pp.45-50
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• 1989

홍삼 및 수삼이 랫트의 간조직에서 diethylnitrosamine(DEN)에 의해 유도되는 preneoplastic altered foci 형성에 미치는 영향을 관찰한 바 다음과 같은 결과를 얻었다. Altered foci의 지표로 사용되는 glutathione S-transferase (GST-P)-positive foci의 숫자는 DEN 단독투여군($9.07{\pm}5.69$)에 비하여 수삼병행 투여군 ($4.77{\pm}3.23$)에서, 면적은 DEN 단독투여군($0.93{\pm}0.65$)에 비하여 홍삼병행투여군 ($0.50{\pm}0.31$)에서 각각 현저한 감소를 나타냈다. 이러한 결과는 홍삼 및 수삼이 간암 발생을 억제하는 작용이 있음을 암시하였다.

• Toxicological Research
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• 제27권4호
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• pp.247-251
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• 2011

To clarify whether inhibitory effect of estrogen on liver tumor is associated with cell proliferation, we investigated its role in diethylnitrosamine (DEN)-induced rat preneoplastic lesions, with time sequenced manners. F344 male rats (n = 90) were divided into three groups at 5 weeks of age. The mini-osmotic pumps providing a continuous infusion of DEN was implanted into the abdominal cavity of each animal in group 1, 2 and 3 at 6 weeks of age. To see the effect of estrogen, pellet containing 1 or 10 ${\mu}g$ of estradiol-3-benzoate (EB) was implanted subcutaneously in the animals of groups 2 or 3, respectively, one week prior to DEN treatment. Ten animals of each group were euthanized at 10, 14 and 18 weeks after DEN treatment. Liver tissues at each time point were fixed in 10% phosphate-buffered formalin and were processed and embedded in paraffin and 5 ${\mu}g$ sections mounted on a silanized slide. Glutathione S-transferase placental form (GST-P) positive foci and 5-bromo-2-deoxyuridine (BrdU) labeling cells were detected at each time point. Area of GST-P positive foci in DEN+EB 1 or 10 ${\mu}g$ group was significantly decreased compared to DEN alone at 14 weeks (p < 0.01 or p < 0.05, respectively) an at 18 weeks (p < 0.05 or p < 0.01, respectively). BrdU index in DEN+EB 1 or 10 ${\mu}g$ groups was significantly decreased compared to DEN alone at 14 weeks and at 18 weeks (p < 0.01). Taken together, we conclude that EB treatment decrease the DEN-induced liver preneoplastic lesions and this may be associated with decrease of cellular proliferation.

• 한국환경성돌연변이발암원학회지
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• 제26권3호
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• pp.86-88
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• 2006

Cytochrome P450 1A2 (CYP1A2) is a xenobiotic metabolizing enzyme that is tissue-specifically expressed in the mammalian liver. In this study, the extent of CYP1A2 promoter methylation was analyzed to determine its potential role in the regulation of CYP1A2 in diethylnitrosamine (DEN)-induced mouse liver tumors. CYP1A2 mRNA was under-expressed about three fold in DEN-induced liver tumors compared to age-matched control livers. The CYP1A2 promoter was hypermethylated in DEN-induced liver tumors compared to controls, especially in a promoter domain close to the coding region. These results suggest that promoter methylation is involved in the regulation of CYP1A2 in mouse liver tumors.

• Asian Pacific Journal of Cancer Prevention
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• 제15권5호
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• pp.2115-2121
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• 2014

The purpose of the present study was to evaluate the preventive effects of hydrazinocurcumin (HZC) on diethylnitrosamine (DEN)-induced hepatocarcinogenesis in a male Sprague Dawley (SD) rat model. One hundred and twenty male SD rats used in this study were divided into six groups. Those receiving DEN with curcumin (CUR) or HZC were studied compared with the DEN-alone group. The study demonstrated that DEN induced severe histological and immunohistochemical changes in liver tissues, significantly increasing the levels of liver marker enzymes (alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), ${\gamma}$-glutamyltransferase (GGT) and total bilirubin level (TBL)). The hepatocarcinoma incidences were 100.0%, 36.7% and 20.0% in the DEN-alone, DEN-CUR and DEN-HZC groups, respectively. Although macroscopic and microscopic features suggested that both CUR and HZC were effective in inhibiting DEN-induced hepatocarcinogenesis, HZC was exerted a stronger influence. Immunohistochemical analysis with PCNA demonstrated significantly differences among the groups (all P < 0.05). Taken together, the results suggested application of CUR and HZC could prevent the occurrence of carcinogenesis and HZC may be a more potent compound for prevention of DEN-induced hepatocarcinogenesis in rats than CUR.

• 대한수의학회지
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• 제31권3호
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• pp.337-342
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• 1991

Caffeine이 랫트의 간조직에서 diethylnitrosamine(200mg/kg B.W., DEN)에 의해 유도되는 preneoplastic altered foci형성의 initiation단계에 미치는 효과를 관찰한 바 다음과 같은 결과를 얻었다. Altered foci의 지표로 사용되는 glutathione S-transferase(GST-P)-positive foci의 수는 caffeine 음수수 ml 당 2mg병행투여군 $(7.48{\pm}3.33)$ 및 1mg 병행 투여군 $(7.50{\pm}3.32)$ 모두에서 DEN 단독투여대조군$(14.08{\pm}5.16)$에 비하여 현저히 낮게 나타났으며, 면적 또한 caffeine 2mg병행투여군 $(0.29{\pm}0.17)$, 1mg병행투여군 $(0.30{\pm}0.13)$에서 DEN단독투여대조군 $(0.46{\pm}0.21)$에 비하여 유의성 있는 낮은 수치가 관찰되었다. 이러한 결과는 caffeine이 간암발생의 initiation 단계에 작용하여 억제효과를 나타냄을 암시하였다.

• 한국환경성돌연변이발암원학회지
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• 제25권4호
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• pp.134-142
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• 2005

Liver cancer is a leading cause of tumor-related mortality, Diethylnitrosamine (DEN) is one of the most extensively studied hepatic carcinogens to date. In this study, the mRNA expression profile in DEN-induced liver tumors in mice was analyzed using DNA microarrays. We report increased expression of genes that participate in hypoxia response, including metallothionein 1 (Mt1), metallothionein 2 (Mt2), fatty acid synthase (Fasn), transferrin (Trf), adipose differentiation-related Protein (AdfP) and ceruloplasmin (CP), as well as those involved in predisposition and development of cancers, such as cytochrome P450 2A5 (Cyp2a5), alpha 2-HS-glycoprotein (Ahsg) and Jun-B oncogene (Junb). The hepatic iron regulatory peptide, hepcidin (Hampl), was downregulated in DEN-stimulated liver tumors. Expression of tumor suppressor genes, such as tripartite motif protein 13 (Trim13), was decreased under these conditions. The data collectively indicate that DEN-induced tumor development can be exploited as a possible model for liver cancer, since this process involves various genes with important functions in hepatic carcinogenesis.

• Asian Pacific Journal of Cancer Prevention
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• 제15권4호
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• pp.1611-1616
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• 2014

Spirogyra neglecta, a freshwater green alga, is a local food in the northern and northeastern parts of Thailand. This investigation explored the anticarcinogenicity of S neglecta and its possible cancer chemopreventive mechanisms in rats divided into 14 groups. Groups 1 and 10 served as positive and negative control groups, respectively. Groups 1-9 were intraperitoneally injected with diethylnitrosamine (DEN) once a week for 3 weeks. Groups 10-14 received normal saline instead. One week after the last DEN injection, groups 2-5 were administered for 9 consecutive weeks various doses of S neglecta extract (SNE) and dried S neglecta (SND), mixed with basal diet. Groups 6-9 and 11-14 similarly were administered various doses of SNE and SND starting from the first week of the experiment. Administration of SNE and SND was not associated with formation of glutathione-Stransferase placental form (GST-P) positive foci in rat liver. SNE and SND during initiation phase significantly reduced the number of GST-P positive foci in rats injected with DEN. The number of GST-P also diminished in groups treated with SNE and SND after injection with DEN, except for the low dose extract group. SNE showed stronger anticarcinogenic potency than SND. Furthermore, SNE also decreased the number of Ki-67 positive cells. However, the numbers of TUNEL-positive cells in the liver of the SNE-treated groups were not statistically different from the controls. The GST activity in 50 mg/kg bw of SNE and 1% of SND groups was significantly increased as compared to the positive control. In conclusion, Spirogyra neglecta (Hassall) K$\ddot{u}$tzing showed cancer chemopreventive properties at the early stages of diethylnitrosamine-induced hepatocarcinogenesis in rats. Possible inhibitory mechanisms include enhancement of the activities of some detoxifying enzymes and/or suppression of precancerous cells.

• 한국환경보건학회지
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• 제32권1호
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• pp.60-66
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• 2006

Bisphenol A(BPA) was known as an endocrine disrupting chemical. This study was conducted to assess the effect of BPA, weaker estrogen, on the preneoplastic and neoplastic lesions induced by diethylnitrosamine (DEN). One hundred male F344 rats were divided into four groups which were treated with DEN followed by BPA. To make liver tumor early, we conducted that DEN containing osmotic pump implanted into rat abdominal cavity. Then diet containing BPA were fed to the rats. All animals were sacrificed at 10 and 18 weeks. Body weights were significantly decreased in 4000ppm at 18 weeks. Relative Liver weights of 4000 ppm BPA treated group were significantly increased compared to that of DEN alone group at 18 weeks. There were no significant differences of liver tumor incidences. Sum area of GST-P positive foci and BrdU labeling indices of BPA treated group were not significantly different compared to those of control group. These results suggest that BPA have no effects in preneoplastic and neoplastic lesions on DEN-induced hepatocarcinogenesis.

• Asian Pacific Journal of Cancer Prevention
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• 제13권8호
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• pp.3627-3630
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• 2012

The epithelial cell adhesion molecule (EpCAM) is a pan-epithelial differentiation antigen that is expressed on almost all carcinomas. However, a role in rat liver carcinogenesis has never been reported previously. Thus, its expression was investigated herein in rat liver tumors induced by diethylnitrosamine (DEN). Twenty male 5-week-old F344 rats were used in this experiment. Mini-osmotic pumps containing doses of 47.5 mg of DEN were inserted into the abdominal cavity of each animal to initiate liver carcinogenesis. All animals were sacrificed at 26 weeks after DEN treatment. At necropsy, hepatic masses were processed for histopathological examination, which revealed forty-four hepatocellular adenomas (HCAs) and twenty hepatocellular carcinomas (HCC). Tumors were immunohistochemically analyzed for EpCAM, proliferating cell nuclear antigen (PCNA) and co-localization of the two. EpCAM expression was mainly detected in hepatic tumor cells, showing a cytoplasmic staining pattern. However, expression was also slightly observed in normally-appearing surrounding hepatic cells. PCNA expression was highly detected in tumor cells, showing nuclear staining. Double staining of EpCAM and PCNA in tumors showed many cells with co-localization. Taken together, EpCAM and PCNA expression were increased in DEN-induced tumors and many tumor cells showed co-expression. It is suggested that EpCAM may increase during DEN-induced tumors, possibly associated with cell proliferation.