Objective: To investigate the dynamic expression pattern of carcinoembryonic Wnt3a and its early monitoring value using a hepatocellular carcinoma model. Methods: Forty-eight Sprague Dawley (SD) rats were fed with pellet feed containing 2-acetylaminofluorene (2-AAF, 0.05%) to induce hepatocarcinogenesis, and control rats were fed a pellet diet. Liver tissue and blood samples were collected every two weeks. Liver tissues were pathologically examined using HE staining and grouped. The gene and Wnt3a mRNA expression were analyzed by genome-wide microarray. The expression and distribution of Wnt3a in liver tissue were analyzed by immunohistochemistry. Wnt3a concentration in liver tissue and serum was quantified by enzyme-linked immunosorbent assay. Statistical methods such as χ² test, Mann-Whitney test and analysis of variance were used to analyze the differences between groups. Results: According to the pathological examination results, the rat livers were divided into four groups: control, hepatocyte degeneration, precancerous lesions and hepatocellular carcinoma. Genome-wide expression profiling analysis and comparison with the control group revealed that 268 and 312 genes were up-regulated and 57 and 201 genes were down-regulated in the precancerous and cancerous group when signal logarithm ratio (SLR) was >8 log₂^cy5/cy3, and these significantly altered genes mainly involved in cell proliferation, signal transduction, tumor metastasis, and apoptosis. The expression of Wnt3a at mRNA level was significantly increased in all stages of cancer induction, including degeneration group (1.15±0.24, q=8.227), precancerous group (1.85±0.18, q=12.361) and cancerous group (2.59±0.55, q=18.082). Compared with the control group (0.25±0.11, F=121.103, P<0.001), the degeneration group, the precancerous group and the liver cancer group were up-regulated by 4.6, 7.4 and 10.4-folds, respectively. Immunohistochemistry showed that compared with the control group, the positive rate of Wnt3a in the degeneration group was 66.7% (12/18, χ²=10.701, P=0.001), and both the precancerous and liver cancer groups were positive (9/9, χ²=17.115, P<0.001). Wnt3a expression was gradually increased in liver and blood samples during the process of carcinogenesis, and the difference between two groups was statistically significant (F=176.711, P<0.001). Wnt3a overexpression was secreted into blood stream via cancerous liver tissue, and there was a linear correlation between Wnt3a levels in blood and liver samples (r=0.732, P<0.001). Conclusions: Wnt3a overexpression is closely related with hepatocellular carcinogenesis, and thus may become a new monitoring marker.
Rats ; Animals ; Carcinoma, Hepatocellular/pathology* ; Liver Neoplasms/pathology* ; Rats, Sprague-Dawley ; Carcinogenesis/metabolism* ; 2-Acetylaminofluorene ; RNA, Messenger/metabolism* ; Precancerous Conditions

OBJECTIVETo study whether the ethanol extract of Phellinus merrillii (EPM) has chemopreventive potential against liver carcinogenesis.

METHODSThirty male Spraque-Dawley rats were randomly divided into control group, EPM control group, hepatocarcinoma control group, low-dose EPM group and high-dose EPM group, 6 in each group. Using the Solt and Farber protocol in a rat model of hepatocarcinogenesis, the chemopreventive effect of EPM on diethylnitrosamine (DEN)-initiated, 2-acetylaminofluorene (2-AAF) and partial hepatectomy (PH)-promoted liver carcinogenesis in rats was evaluated. Basic pathophysiological and histological examinations, together with the serum levels of glutamic oxaloacetic transaminase (sGOT), glutamic pyruvic transaminase (sGPT) and gamma-glutamyl transpeptidase (γ-GT) were measured.

RESULTSTreatment of EPM at the concentration of 2 g/kg body weight in the diet for 8 weeks clearly prevented the development of carcinogenesis and reduced the levels of sGOT, sGPT, and serum γ-GT of rats as compared with the hepatocarcinoma control group (P<0.05 or P<0.01). These phenotypes were accompanied by a significant increase in natural killer cell activity.

CONCLUSIONEPM showed a strong liver preventive effect against DEN+2-AAF+PH-induced hepatocarcinogenesis in a rat model.

2-Acetylaminofluorene ; Animals ; Basidiomycota ; chemistry ; Carcinogenesis ; chemically induced ; Cytoprotection ; drug effects ; Diethylnitrosamine ; Ethanol ; chemistry ; Liver Neoplasms, Experimental ; chemically induced ; prevention & control ; Male ; Plant Extracts ; chemistry ; pharmacology ; Protective Agents ; pharmacology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the possible mechanisms of miR-21-mediated regulation of proliferation and activation of hepatic oval cells.

METHODSThe 2-acetamidofluorene/partial hepatectomy (2-AAF/PH) method was applied to generate hepatic oval cell activation model in male Sprague-Dawley rats; after the 7 days of 2-AAF/PH or PH alone (control), the rats were sacrificed at 0 h, 6 h, 12 h, 24 h, 72 h and 168 h. Expression of miR-21 was detected by real-time PCR and differences between groups were evaluated using the two-sample t-test. Differential transcription of miR-21 target genes was assessed bioinformatically, and with western blotting to detect changes in protein expression of the target gene.

RESULTSThe rat hepatic oval cell activation model was successfully established.The 2-AAF/PH rats showed miR-21 expression beginning to increase at 12 h, peaking at 24 h, and decreasing thereafter until an increase at 168 h.For the control group, the miR-21 expression began to increase at 6 h, until 24 h when expression began steadily declining to reach the original level.Compared to the control group, the experimental group showed expression of miR-21 that was significantly less at 6 h (P=0.039, t =3.029) and significantly more at 24 h and 168 h (P=0.026, t =-3.433 and P=0.007, t =-5.105). Among the predicted target genes of miR-21 were WW domain containing E3 ubiquitin protein ligase 1 (WWD), Smad family member 7 (Smad7), and polybromo-1 (Pbrm1).Smad7 protein expression began to decrease at 6 h in the control group, until reaching its minimum at 24 h when it increased; in the experimental group, SMAD7 expression increased at 6 h, then began to decrease with the minimum detected at 168 hour.In the control group, the Smad7 mRNA expression decreased slightly at 6 h, then began to increase, reaching its peak at 24 h when the expression fell to the original level. In the experimental group, the Smad7 mRNA expression began to increase at 6 h and reached its peak at 24 h when it decreased; the expression was little more than its original level at 168 h.Smad7 protein expression was negatively correlated with miR-21, and Smad7 mRNA expression was positively correlated with miR-21 but negatively correlated with Smad7 protein expression.

CONCLUSIONmiR-21 may play a vital role in the activation and proliferation of hepatic oval cells.As a target gene of miR-21, Smad7 might be involved in the process.

2-Acetylaminofluorene ; Animals ; Cell Proliferation ; Hepatectomy ; Hepatocytes ; cytology ; Liver ; cytology ; Male ; MicroRNAs ; genetics ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction

BACKGROUND/AIMS: In the 2-acetylaminofluorene (2-AAF)/70% partial hepatectomy (PHx) model, the mechanism underlying the differentiation of activated hepatic oval cells (HOCs) into hepatocytes and bile ductile cells is unclear. We investigated the role of cyclooxygenase-2 (COX-2) in HOCs and the relationship between COX-2 and extracellular matrix proteins in cellular proliferation. METHODS: Reverse transcription-polymerase chain reaction, immunohistochemical staining, and Western blotting were used to assess COX-2 expression. The co-localization of COX-2 with Thy1, c-Met, epithelial cell adhesion molecule, and alpha-smooth muscle actin was also examined. Additionally, we investigated whether connective tissue growth factor (CTGF), fibronectin (FN), extracellular signal-regulated kinase 1/2 (P-ERK1/2), and AKT were expressed in HOCs. RESULTS: The expression of COX-2, prostaglandin E2 receptors, and c-Met was upregulated in HOCs. However, HOCs treated with the COX-2 inhibitor NS398 showed decreased COX-2, CTGF, FN, and AKT expression, whereas P-ERK1/2 was unaffected. Additionally, NS398 inhibited HOC proliferation, but not the proliferation of HOCs cultured on FN-coated dishes. Furthermore, the proliferative response of HOCs treated with NS398 was reversed by hepatic growth factor treatment. CONCLUSIONS: These results suggest that HOC proliferation is mediated through COX-2, extracellular FN expression, and AKT activation. Thus, COX-2 plays an important role in HOC proliferation following acute injury.
2-Acetylaminofluorene ; Actins ; Animals ; Antigens, Neoplasm ; Bile ; Blotting, Western ; Cell Adhesion Molecules ; Connective Tissue Growth Factor ; Cyclooxygenase 2 ; Dinoprostone ; Epithelial Cells ; Extracellular Matrix ; Extracellular Matrix Proteins ; Fibronectins ; Hepatectomy ; Hepatocytes ; Liver ; Liver Regeneration ; Muscles ; Nitrobenzenes ; Phosphotransferases ; Rats ; Sulfonamides

OBJECTIVETo investigate the changes of oval cell proliferation rate in the rat 2-acetylaminofluorene/partial hepatectomy (2-AAF/PH) model.

METHODSLivers were collected from 2-AAF/PH rats at different time points after hepatectomy. Paraffin sections were investigated by double immunofluorescent staining with confocal microscopy for oval cell marker epithelial cell adhesion molecule and proliferative index proliferating cell nuclear antigen, or epithelial cell adhesion molecule and alpha-smooth muscle actin. Deposition of matrix in liver tissue was detected by sirius red staining.

RESULTSResponse of ductular oval cells could be observed in portal area at 2 days after PH, and the number of oval cells reached its peak at 9 days and then gradually declined. Oval cell proliferation rate decreased from (91.3 +/- 1.6)% at 2 days after PH to (53.6 +/- 4.4)% at 12 days (P < 0.01). In addition, oval cells infiltrating into liver parenchyma were closely associated with activated hepatic stellate cells and extracellular matrix.

CONCLUSIONSOval cell proliferation rate starts decreasing before its number reaches a peak in 2-AAF/PH model. Hepatic stellate cells probably tightly regulate oval cell number through secreting several factors and producing extracellular matrix.

2-Acetylaminofluorene ; pharmacology ; Animals ; Cell Division ; Cell Proliferation ; Hepatectomy ; Liver ; cytology ; Male ; Rats ; Rats, Sprague-Dawley ; Stem Cells ; cytology

2-Acetylaminofluorene ; Angiogenesis Inhibitors ; pharmacology ; Animals ; Carcinoma, Hepatocellular ; chemically induced ; metabolism ; pathology ; Immunohistochemistry ; Liver ; drug effects ; metabolism ; pathology ; Liver Neoplasms, Experimental ; chemically induced ; metabolism ; pathology ; Male ; NF-kappa B ; antagonists & inhibitors ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Thalidomide ; pharmacology

The purpose of this study was to investigate the effects of green tea ingestion on hepatocarcinogenesis before and after its initiation. Male Sprague-Dawley rats were fed an AIN76A diet with or without green tea. Initiation was induced by a single dose (200 mg/kg) of diethylnitrosamine at week 4 and 0.02% (w/w) 2-acetylaminofluorene was supplied in the diets. The control group had free access to water for 13 weeks (CTR13). Tea infusion was provided from the beginning of the experiment for 13 weeks (PRE13) or from the post-initiation stage until week 13 (POST13). Three other groups (CTR24, PRE24 and POST24) were added to examine the longer-term effects (24 weeks) with the same experimental design. The percentage area of liver sections that were positive for hepatic placental glutathione S-transferase (GST-P), which was used as a marker of preneoplastic lesions, was smaller in PRE13 (20.2 +/- 5.0%, mean +/- SD) and POST13 (26.0 +/- 4.8%) than in CTR13 (33.2 +/- 5.8%, p<0.05). Over the longer period, the GST-P lesions were significantly smaller for both PRE24 and POST24 (21.6 +/- 8.5% and 22.2 +/- 4.0%, respectively) than for CTR24 (28.6 +/- 5.1%, p<0.05), but there was no significant difference between PRE24 and POST24. The liver content of thiobarbituric acid reactive substances was significantly lower in the tea groups than in the controls (p<0.05). However, no significant differences were observed among groups of GST activity. The results show that tea consumption exhibits a stronger short-term initiation-inhibiting ability in liver carcinogenesis, but over a longer period, the preventive effects of green tea ingestion do not differ in post- and pre-initiation.
2-Acetylaminofluorene ; Animals ; Diet ; Diethylnitrosamine ; Eating ; Glutathione Transferase ; Humans ; Liver ; Male ; Rats ; Rats, Sprague-Dawley ; Research Design ; Tea ; Thiobarbiturates ; Thiobarbituric Acid Reactive Substances ; Water

This study sought to isolate and purify C-kit+ cells from rat 2-AAF/PH model and to investigate the proliferation and differentiation of C-kit+ cells in vitro. C-kit positive oval cells were enriched by using magnetic activated cell sorting (MACS). The sorted oval cells were cultured in a low density, and then colony formation was observed. The capacity of proliferation and differentiation of C-kit positive cells were examined in vitro by immunocytochemistry and RT-PCR. By using C-kit antibody in conjunction with MACS, we developed a rapid oval cell isolation protocol. The sorted cells formed colony when cultured in vitro. Cells in the colony expressed albumin or cytokeratin 19 (CK19) or coexpressed both, and BrdU incorporation test was positive. RT-PCR on colony showed expression of albumin and CK19 gene. The results demonstrate that by means of MACS we have established a method to isolate oval cells. The sorted hepatic oval cells can form colony in vitro which expresses different combinations of phenotypic markers and genes from both hepatocytes and cholangiocyte lineage.
2-Acetylaminofluorene ; pharmacology ; Animals ; Animals, Newborn ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Hepatocytes ; cytology ; metabolism ; Male ; Proto-Oncogene Proteins c-kit ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Stem Cells ; cytology ; metabolism

OBJECTIVETo investigate the effects of herbal compound 861 (Cpd861) on hepatocarcinogenesis induced by diethylntrosamine and 2-acetylaminofluorene (DEN-AAF) in female Sprague Dawley rats.

METHODSLiver preneoplastic foci were induced using the DEN-AAF method in female Sprague Dawley rats, which were then treated with Cpd861. For quantitative assessment of liver preneoplastic foci, the placental form of glutathione-S-transferase (GST-P) positive foci were measured using immunohistochemical staining and image analysis. GST-P protein expression was measured by Western blotting, mRNA expression was assessed by Northern blotting.

RESULTSTreatment using DEN-AAF caused a significant decrease in body weight and increase in liver weight compared to the control group. Oral Cpd861 administration essentially prevented DEN-AAF-induced body weight loss and liver weight increase. When 2-AAF was followed by treatment with Cpd861, there was a decrease in the number of large foci as compared to 2-AAF alone. However, there were still considerable numbers of small mixed clear/vacuolated cell foci, some of which were positive for GST-P. Significant increase in GST-P protein and mRNA expression were observed in the DEN-AAF group, while treatment with Cpd861 inhibited the increase. The effect of Cpd861 on hepatocarcinogenesis occurred in a concentration-dependent manner.

CONCLUSIONChinese herbal compound Cpd861 prevents hepatocarcinogenesis in DEN-AAF-induced liver preneoplastic lesions in rats.

2-Acetylaminofluorene ; Animals ; Blotting, Northern ; Blotting, Western ; Body Weight ; Diethylnitrosamine ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Glutathione Transferase ; genetics ; Liver ; pathology ; Liver Neoplasms, Experimental ; chemically induced ; drug therapy ; pathology ; Organ Size ; Rats ; Rats, Sprague-Dawley

PURPOSE: The proliferative activity of cells in enzyme altered fdegrees Ci of the rat hepatoma model was measured by double immunohistdegrees Chemical staining methods using anti-bromodeoxyuridine (BrdU) and anti-glutathione S transferase of placental form (GST-P). The aim of this study was to compare the cell proliferative activity in GST-P positive altered fdegrees Ci and in negative fdegrees Ci. MATERIALS AND METHODS: Eight-week-old male Sprague-Dawley rats were administered by 200 mg/kg diethylnitrosamine (DEN) intraperitoneally, and followed by 0.02% acetylaminofluorene (AAF)-containing diet for 4 weeks. One week after administration of AAF diet, two-thirds hepa tectomy was performed. Control animals were treated as same except for the omission of AAF in the diet. The rats were sacrified 0, 1, 3, 5, 7, 14 and 21 days after partial hepatectomy. The slices of liver were fixed in acetone, dehydrated in benzene and stained by peroxidase-anti peroxidase method against GST-P and by avidine-biotin peroxidase complex method against BrdU. RESULTS: The area of the GST-P positive fdegrees Ci was increased during the experimental period. In the experimental group, the S-phase fraction in the fdegrees Ci remained high during the first week and was decreased thereafter. However, the GST-P negative area maintained a low S-phase cell frac tion throughout the experimental period. CONCLUSION: These results suggest that hepatic cells in the enzyme altered fdegrees Ci may escape a suppressor effect of AAF in contrast to the normal cells in which their growth are inhibited by AAF.
2-Acetylaminofluorene ; Acetone ; Animals ; Benzene ; Bromodeoxyuridine ; Carcinogenesis* ; Carcinoma, Hepatocellular ; Diet ; Diethylnitrosamine ; Hepatectomy ; Hepatocytes ; Humans ; Liver ; Male ; Peroxidase ; Rats* ; Rats, Sprague-Dawley ; Transferases ; United Nations