Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aflatoxin B(1) (AFB(1)) causes oxidative stress and ROS formation via metabolic activation of AFB(1). Glycyrrhizic acid (GA) has been reported to have antioxidative properties. The present study was to investigate the effect of GA, a major component of licorice on AFB(1)-induced cytotoxicity in human hepatoma cell line (HepG2). GA displayed protective effects against AFB(1) treatment. Both CYP1A1, and glutathione S-transferase (GST) activities were increased in cells after treatment with the GA, while CYP1A2 did not seem to be affected by GA. For cells without GA pre-treatment, cell injury was implicated as indicated by the decrease in cell viability. The time-course study of GA showed pretreatment of cells with GA for 24 h was effective. The treatment of cells with GA and AFB(1) enhanced the detoxifying enzyme activity. The pre-treatment of cells with GA provides protective effects in terms of the enzyme activity and increase in cell viability. The results suggest that GA protects against aflatoxin-induced oxidative stress. This may contribute to its anticarcinogenic capability. The protective effect is likely due to its capacity to inhibit the metabolic activation of hepato-toxin, a critical factor in the pathogenesis of chemical-induced carcinogenicity.
 ...
PMID:Inhibition of glycyrrhizic acid on aflatoxin B1-induced cytotoxicity in hepatoma cells. 1276 92

CYP1A2 polymorphism has been well studied in white persons and Asians but not in Africans. We performed CYP1A2 genotype and phenotype analysis using caffeine in Ethiopians living in Ethiopia (n = 100) or in Sweden (n = 73). We sequenced the CYP1A2 gene using genomic DNA from 12 subjects, which revealed a novel intron 1 single-nucleotide polymorphism (SNP), -730C>T. We developed SNP-specific polymerase chain reaction-restriction fragment length polymorphism genotyping and molecular haplotyping methods for the intron 1 SNPs, and four different haplotypes were identified: CYP1A2*1A (wild-type for all SNPs), CYP1A2*1F (-164A), CYP1A2*1J (-740G and -164A), and CYP1A2*1K (-730T, -740G, and -164A), having frequencies of 39.9, 49.6, 7.5, and 3.0%, respectively. The frequency of CYP1A2*1J and CYP1A2*1K among Saudi Arabians (n = 136) was 5.9% and 3.6%, and among Spaniards (n = 117) 1.3% and 0.5%, respectively. Functional significance of the different intron 1 haplotypes was analyzed. Subjects with CYP1A2*1K had significantly decreased CYP1A2 activity in vivo, and reporter constructs with this haplotype had significantly less inducibility with 2,3,7,8-tetrachlorodibenzo-p-dioxin in human B16A2 hepatoma cells. Electrophoretic mobility shift assay using nuclear extracts from B16A2 cells revealed a specific DNA binding protein complex to an Ets element. Efficient competition was obtained using oligonucleotide probes carrying the wt sequence and Ets consensus probe, whereas competition was abolished using probes with the -730C>T SNP alone or in combination with -740T>G (CYP1A2*1K). The results indicate a novel polymorphism in intron 1 of importance for Ets-dependent CYP1A2 expression in vivo and inducibility of the enzyme, which might be of critical importance for determination of interindividual differences in drug metabolism and sensitivity to carcinogens activated by CYP1A2.
 ...
PMID:Genetic polymorphism of CYP1A2 in Ethiopians affecting induction and expression: characterization of novel haplotypes with single-nucleotide polymorphisms in intron 1. 1292 Feb 2

The aryl hydrocarbon receptor (AhR) is involved in various processes such as cytochrome P450 (P450) 1A induction after xenobiotic exposure. It is also considered to play a major role in cell proliferation and differentiation. Recent evidences have suggested a cross-talk between AhR functions and the mitogen-activated protein kinase (MAPK) cascade. We now report that 1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene (U0126), a specific inhibitor of MAPK kinase (MEK) MEK1/2, elicits a marked increase in CYP1A1 expression at both mRNA and protein levels associated with a significant increase of enzyme activity in primary rat hepatocytes and a human hepatoma cell line. This induction occurred independently of MEK/extracellular signal-regulated kinase (ERK) activation and in the absence of ERK1 and ERK2 expression. The effect of U0126 was mediated by its ability to transactivate xenobiotic responsive element (XRE)-driven genes, as demonstrated by transfection assays with an XRE-driven luciferase construct in the human B16A2 hepatoma cell line. CYP1A1 modulation was abolished by a cotreatment with resveratrol, an established AhR antagonist, arguing for AhR activation by U0126. Such an effect was demonstrated by direct in vitro ligand binding competition assays using rabbit liver cytosol, showing that this compound binds AhR with an EC(50) = 25 x 10(-6) M. Moreover, we demonstrated that U0126 is a substrate for several P450s including human CYP1A2, -1A1, and -1B1. We conclude that the widely used specific inhibitor of MEK/ERK, U0126, also acts as a potent AhR activator and an inducer of related genes. Such effects on the AhR may have an impact on biological functions attributed previously to MAPK inhibition.
 ...
PMID:Aryl hydrocarbon receptor activation and cytochrome P450 1A induction by the mitogen-activated protein kinase inhibitor U0126 in hepatocytes. 1504 23

Aim of the study was to investigate the usefulness of two human derived hepatoma cell lines (HepG2 and Hep3B) for the detection of dietary and lifestyle related DNA-reactive carcinogens. Comparisons of the sensitivity of HepG2 cells of different origin towards benzo[a]pyrene (B(a)P) showed that strong differences exist in the induction of micronuclei (MN). The most sensitive was used for all further experiments, in which we investigated the effects of aflatoxin B(1) (AFB(1)), B(a)P, As(2)O(3), CdCl(2), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), ethanol, acetaldehyde and caffeic acid in micronucleus (MN) tests. Dose dependent effects were detected in HepG2 with AFB(1) (0.2microM), CdCl(2) (2.2microM), As(2)O(3) (8.1microM), B(a)P (22.7microM), PhIP (35.7microM), NDMA (22.7mM), acetaldehyde (11.2mM) and ethanol (442.2mM). Numbers in parentheses indicate the C(D) values (concentration that induced a two-fold increase over the background). NNK and caffeic acid gave negative results under all conditions. In Hep3B cells, the effects were generally weaker. With PhIP, As(2)O(3) and NDMA negative results were obtained; with caffeic acid and NPYR marginal but significant induction of MN was observed. Enzyme measurements showed that both cell lines possess CYP1A1, glutathione-S-transferase (three-fold higher in HepG2) as well as N-acetyltransferase (NAT) 1 and sulfotransferases (SULT1A1 and SULT1A3; two- and seven-fold higher in HepG2); other cytochrome P450 enzymes (CYP1A2, 2B1, 2E1) and NAT2 were not detectable. The differences in the activities of the various enzymes may explain the contrasting results obtained in the MN experiments. Overall, our results indicate that the HepG2 line is more sensitive towards dietary genotoxins than Hep3B, and support the assumption that the HepG2/MN assay enables the detection of genotoxic carcinogens which give negative results in other currently used in vitro assays.
 ...
PMID:Genotoxic effects of dietary and lifestyle related carcinogens in human derived hepatoma (HepG2, Hep3B) cells. 1522 90

R126638 is a novel triazole with in vitro activity similar to that of itraconazole against dermatophytes, Candida spp., and Malassezia spp. In animal models of dermatophyte infections, R126638 showed superior antifungal activity. R126638 inhibits ergosterol synthesis in Candida albicans, Trichophyton mentagrophytes, Trichophyton rubrum, and Microsporum canis at nanomolar concentrations, with 50% inhibitory concentrations (IC(50)s) similar to those of itraconazole. The decreased synthesis of ergosterol and the concomitant accumulation of 14 alpha-methylsterols provide indirect evidence that R126638 inhibits the activity of CYP51 that catalyzes the oxidative removal of the 14 alpha-methyl group of lanosterol or eburicol. The IC(50)s for cholesterol synthesis from acetate in human hepatoma cells were 1.4 microM for itraconazole and 3.1 microM for R126638. Compared to itraconazole (IC(50) = 3.5 microM), R126638 is a poor inhibitor of the 1 alpha-hydroxylation of 25-hydroxyvitamin D(3) (IC(50) > 10 microM). Micromolar concentrations of R126638 and itraconazole inhibited the 24-hydroxylation of 25-hydroxyvitamin D(3) and the conversion of 1,25-dihydroxyvitamin D(3) into polar metabolites. At concentrations up to 10 microM, R126638 had almost no effect on cholesterol side chain cleavage (CYP11A1), 11 beta-hydroxylase (CYP11B1), 17-hydroxylase and 17,20-lyase (CYP17), aromatase (CYP19), or 4-hydroxylation of all-trans retinoic acid (CYP26). At 10 microM, R126638 did not show clear inhibition of CYP1A2, CYP2A6, CYP2D6, CYP2C8, CYP2C9, CYP2C10, CYP2C19, or CYP2E1. Compared to itraconazole, R126638 had a lower interaction potential with testosterone 6 beta hydroxylation and cyclosporine hydroxylation, both of which are catalyzed by CYP3A4, whereas both antifungals inhibited the CYP3A4-catalyzed hydroxylation of midazolam similarly. The results suggest that R126638 has promising properties and merits further in vivo investigations for the treatment of dermatophyte and yeast infections.
 ...
PMID:The novel azole R126638 is a selective inhibitor of ergosterol synthesis in Candida albicans, Trichophyton spp., and Microsporum canis. 1532 84

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related chemicals induce cytochrome P450 1A (CYP1A) gene expression and, at sufficient exposures, cause toxicity. Human health risks from such exposures are typically estimated from animal studies. We tested whether animal models predict human sensitivity by characterizing CYP1A gene expression in cultures of fresh hepatocytes from human donors, rats, and rhesus monkeys and HepG2 human hepatoma cells. We exposed the cells to three aryl hydrocarbon receptor (AhR) ligands of current environmental interest and measured 7-ethoxyresorufin-O-deethylase (EROD) activity and concentrations of CYP1A1 and CYP1A2 mRNA. We found that human cells are about 10-1000 times less sensitive to TCDD, 3,3',4,4',5-pentachlorobiphenyl (PCB 126), and Aroclor 1254 than rat and monkey cells, that relative potencies among these chemicals are different across species, and that gene expression thresholds exist for these chemicals. Newly calculated rat-human interspecies relative potency factors for PCB 126 were more than 100 times lower than the current rodent-derived value. We propose that human-derived values be used to improve the accuracy of estimates of human health risks.
 ...
PMID:Comparison of TCDD and PCB CYP1A induction sensitivities in fresh hepatocytes from human donors, sprague-dawley rats, and rhesus monkeys and HepG2 cells. 1604 71

Most human hepatocyte cell lines lack a substantial set of liver-specific functions, especially major cytochrome P450 (P450)-related enzyme activities, making them unrepresentative of in vivo hepatocytes. We have used the HepaRG cells, derived from a human hepatocellular carcinoma, which exhibit a high differentiation pattern after 2 weeks at confluency to determine whether they could mimic human hepatocytes for drug metabolism and toxicity studies. We show that when passaged at low density, these cells reversed to an undifferentiated morphology, actively divided, and, after having reached confluency, formed typical hepatocyte-like colonies surrounded by biliary epithelial-like cells. By contrast, when seeded at high density, hepatocyte-like clusters retained their typical differentiated morphology. Transcripts of various nuclear receptors (aryl hydrocarbon receptor, pregnane X receptor, constitutive androstane receptor, peroxisome proliferator-activated receptor alpha), P450s (CYP1A2, 2C9, 2D6, 2E1, 3A4), phase 2 enzymes (UGT1A1, GSTA1, GSTA4, GSTM1), and other liver-specific functions were estimated by reverse transcriptase-quantitative polymerase chain reaction and were found to be expressed, for most of them, at comparable levels in both confluent differentiated and high-density differentiated HepaRG cells and in cultured primary human hepatocytes. For several transcripts, the levels were strongly increased in the presence of 2% dimethyl sulfoxide. Measurement of basal activities of several P450s and their response to prototypical inducers as well as analysis of metabolic profiles and cytotoxicity of several compounds confirmed the functional resemblance of HepaRG cells to primary cultured human hepatocytes. In conclusion, HepaRG cells constitute the first human hepatoma cell line expressing high levels of the major P450s involved in xenobiotic metabolism and represent a reliable surrogate to human hepatocytes for drug metabolism and toxicity studies.
 ...
PMID:Expression of cytochromes P450, conjugating enzymes and nuclear receptors in human hepatoma HepaRG cells. 1620 62

Hepatocyte nuclear factor 4alpha (HNF4alpha) is a key transcription factor for the constitutive expression of cytochromes P450 (P450s) in the liver. However, human hepatoma HepG2 cells show a high level of HNF4alpha but express only marginal P450 levels. We found that the HNF4alpha-mediated P450 transcription in HepG2 is impaired by the low level of coactivators peroxisomal proliferator activated receptor-gamma coactivator 1alpha (PGC1alpha) and steroid receptor coactivator 1 (SRC1). Reporter assays with a chimeric CYP2C9-LUC construct demonstrated that the sole transfection of coactivators induced luciferase activity in HepG2 cells. In HeLa cells however, CYP2C9-LUC activity only significantly increased when coactivators were cotransfected with HNF4alpha. A deletion mutant lacking the two proximal HNF4alpha binding sites in the CYP2C9 promoter did not respond to PGC1alpha or SRC1, demonstrating that coactivators were acting through HNF4alpha response elements. Adenovirus-mediated transfection of PGC1alpha in human hepatoma cells caused a significant dose-dependent increase in CYP2C9, CYP1A1, and CYP1A2 and in the positive control CYP7A1. PGC1alpha also showed a moderate activating effect on CYP3A4, CYP3A5, and CYP2D6. Adenoviral transfection of SRC1 had a lessened effect on P450 genes. Chromatin immunoprecipitation assay demonstrated in vivo binding of HNF4alpha and PGC1alpha to HNF4alpha response sequences in the CYP2C9 promoter and to three new regulatory regions in the common 23.3 kilobase spacer sequence of the CYP1A1/2 cluster. Insulin treatment of HepG2 and human hepatocytes caused repression of PGC1alpha and a concomitant down-regulation of P450s. Our results establish the importance of coactivators PGC1alpha and SRC1 for the hepatic expression of human P450s and uncover a new HNF4alpha-dependent regulatory mechanism to constitutively control the CYP1A1/2 cluster.
 ...
PMID:Transcriptional activation of CYP2C9, CYP1A1, and CYP1A2 by hepatocyte nuclear factor 4alpha requires coactivators peroxisomal proliferator activated receptor-gamma coactivator 1alpha and steroid receptor coactivator 1. 1688 80

DIOXIN TOXIC EQUIVALENCY FACTOR EVALUATION OVERVIEW: Polyhalogenated aromatic hydrocarbons such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) have the ability to bind to and activate the ligand-activated transcription factor, the aryl hydrocarbon receptor (AhR). Structurally related compounds that bind to the AhR and exhibit biological actions similar to TCDD are commonly referred to as "dioxin-like compounds" (DLCs). Ambient human exposure to DLCs occurs through the ingestion of foods containing residues of DLCs that bio-concentrate through the food chain. Due to their lipophilicity and persistence, once internalized they accumulate in body tissues, mainly adipose, resulting in chronic lifetime human exposure. Since human exposure to DLCs always occurs as a complex mixture, the toxic equivalency factor (TEF) methodology has been developed as a mathematical tool to assess the health risk posed by complex mixtures of these compounds. The TEF methodology is a relative potency scheme that ranks the dioxin-like activity of a compound relative to TCDD, the most potent congener. This allows for the estimation of the potential dioxin-like activity of a mixture of chemicals, based on a common mechanism of action involving an initial binding of DLCs to the AhR. The toxic equivalency of DLCs was nominated for evaluation because of the widespread human exposure to DLCs and the lack of data on the adequacy of the TEF methodology for predicting relative potency for cancer risk. To address this, the National Toxicology Program conducted a series of 2-year bioassays in female Harlan Sprague-Dawley rats to evaluate the chronic toxicity and carcinogenicity of DLCs and structurally related polychlorinated biphenyls (PCBs) and mixtures of these compounds. 2-YEAR STUDY: The 2-year study of a binary mixture of PCB 126 and PCB 153 was designed to assess the carcinogenicity of a constant ratio mixture of PCB 126 and PCB 153. In addition, varying ratio mixture groups were used to assess the impact of increasing PCB 153 on the carcinogenicity of PCB 126. Dose groups were divided into two study arms (Figure 1). TCDD equivalent (TEQ) doses are based on the PCB 126 doses after adjustment for the PCB 126 TEF of 0.1. Groups of 81 (Groups 2, 3, 5, and 7) or 80 (Groups 4 and 6) female rats received a mixture of PCB 126 and PCB 153 in corn oil:acetone (99:1) by gavage 5 days per week for up to 105 weeks; a group of 81 female rats received the corn oil:acetone (99:1) vehicle only and served as the vehicle control (Group 1). Up to 10 rats per group were evaluated at 14, 31, and 53 weeks. Survival of all dosed groups was similar to that of the vehicle controls. The mean body weights of Groups 4 and 5 were generally less than those of the vehicle controls after week 25. The mean body weights of Group 6 were less after week 12, and those of Group 7 were less after week 8. Thyroid Hormone Concentrations: Alterations in serum thyroid hormone levels were evaluated at the 14-, 31-, and 53-week interim evaluations. In the constant ratio groups, serum total thyroxine (T(4)) and free T(4) generally showed a treatment-related decrease relative to controls. Serum total triiodothyronine (T(3)) exhibited a treatment-related increase at the 14-, 31-, and 53-week interim evaluations, but serum thyroid stimulating hormone (TSH) levels were increased at the 14-week time point only. In the varying ratio groups, the decrease in total and free T(4) was more pronounced in those groups dosed with the increasing proportion of PCB 153 at the 31- and 53-week time points. Hepatic Cell Proliferation Data: To evaluate hepatocyte replication, analysis of labeling of replicating hepatocytes with 5-bromo-2'-deoxyuridine was conducted at the 14-, 31-, and 53-week interim evaluations. At 31 and 53 weeks, a significant increase in the hepatocellular labeling index occurred in Group 7. In the varying ratio groups, the labeling index at the 53-week interim time point was significantly higher in Group 6, which had the highest proportion of PCB 153 compared to the other varying ratio groups. Cytochrome P450 Enzyme Activities: To evaluate the expression of known PCB 126-responsive genes, CYP1A1-associated 7-ethoxyresorufin-O-deethylase (EROD) and CYP1A2-associated acetanilide-4-hydroxylase (A4H) activities were evaluated at the 14-, 31-, and 53-week interim evaluations. In addition, PCB 153-inducible CYP2B-associated 7-pent-oxyresorufin-O-dealkylase (PROD) activity was analyzed. In the constant ratio Groups 2, 3, 5, and 7, hepatic and pulmonary EROD (CYP1A1) activities, hepatic A4H (CYP1A2) activities, and hepatic PROD (CYP2B) activities were significantly greater in all dosed groups compared to the vehicle controls at weeks 14, 31, and 53. In the varying ratio groups, hepatic EROD, A4H, and PROD activities at 14 weeks were higher in groups receiving a greater proportion of PCB 153 in the PCB mixture. At 31 and 53 weeks, hepatic CYP1A1 and CYP1A2 enzyme activities in Group 6 were generally lower than in Groups 4 and 5. Determinations of PCB 126 and PCB 153 Concentrations in Tissues: Concentrations of PCB 126 and PCB 153 were determined in fat, liver, lung, and blood at the 14-, 31-, and 53-week interim evaluations and at the end of the 2-year study (105 weeks). PCB 126 was not detectable in vehicle control animals, but increased with increasing dose of PCB 126 and duration of exposure; the highest concentrations were found in liver and fat, and lower levels were seen in lung and blood. Increasing the proportion of PCB 153 in the mixture relative to PCB 126 led to a general decrease in the amount of PCB 126 in liver and lung at the later time points, whereas in fat and blood, there was generally either no effect of PCB 153 on the disposition of PCB 126, or there was an increase in the amount of PCB 126 in the tissue. In vehicle control animals, PCB 153 was detectable in the fat at all time points, in the lung at all time points except 53 weeks, and in the liver and blood at 2 years. PCB 153 was measurable in all examined tissues of treated animals, with the highest concentrations found in fat at the end of the 2-year study in groups administered the highest doses of PCB 153. Pathology and Statistical Analyses -- Constant Ratio Mixture of PCB 126 and PCB 153: At 14, 31, and 53 weeks, the absolute and relative liver weights of all dosed groups were generally greater than those of the vehicle controls. Exposure to the PCB mixture led to significant toxicity in the liver. At 14 weeks, the incidences of several nonneoplastic liver lesions were increased compared to the vehicle controls including hepatocyte hypertrophy, pigmentation, multinucleated hepatocytes, and diffuse fatty change. The spectrum and severity of effects increased with dose and duration of exposure. At the end of the 2-year study, there were significantly increased incidences and severities of toxic hepatopathy characterized by hepatocyte hypertrophy, multinucleated hepatocytes, pigmentation, diffuse and focal fatty change, eosinophilic focus, nodular hyperplasia, cholangiofibrosis, oval cell hyperplasia, bile duct cysts, bile duct hyperplasia, necrosis, and portal fibrosis. Significantly increased incidences of hepatocellular adenoma, cholangiocarcinoma, and hepatocholangioma were observed in the study. In addition, two animals in the highest dose group had hepatocellular carcinoma. The incidences of these lesions generally exceeded the historical vehicle control ranges. At 2 years, a significantly increased incidence of cystic keratinizing epithelioma of the lung was observed in Group 7. In addition, single occurrences of squamous cell carcinoma were seen in the top two dose groups. Nonneoplastic effects whose incidences were increased in the lung included bronchiolar metaplasia of the alveolar epithelium and squamous metaplasia. Significantly increased incidences of squamous cell carcinoma (gingival) of the oral mucosa were seen at the end of the 2-year study and were accompanied by increased incidences of gingival squamous hyperplasia. In the pancreas at 53 weeks, the incidence of acinar cytoplasmic vacuolization was significantly increased in the highest dose group. At 2 years, increased incidences of acinar atrophy and acinar cytoplasmic vacuolization were seen in addition to pancreatic acinar neoplasms in dosed groups. In Groups 5 and 7, these incidences exceeded the historical vehicle control ranges. In the uterus at 2 years, there was a marginal increase in the incidence of squamous cell carcinoma in Group 5. Numerous nonneoplastic effects were seen in other organs at the interim time points including atrophy of the thymus and follicular cell hypertrophy of the thyroid gland. These responses were also affected by administration of the mixture of PCB 126 and PCB 153 at the end of the 2-year study and were accompanied by additional nonneoplastic responses in numerous organs including atrophy of the adrenal cortex and cortical hyperplasia, severity of nephropathy, and incidences of pigmentation of the kidney. Other nonneoplastic lesions that were treatment related were forestomach hyperplasia, hyperplasia of the nasal respiratory epithelium, metaplasia of the olfactory epithelium, and ectasia of the mandibular lymph node. Varying Ratio Mixture of PCB 126 and PCB 153: An effect of increasing the proportion of PCB 153 in the PCB mixture was seen in several tissues, most notably in the liver. Treatment-related nonneoplastic effects seen across the varying ratio groups were generally the same as those seen in the constant ratio groups. In general there was a positive effect of PCB 153 in the mixture on the incidences and severities of these lesions with higher incidences and higher severities being seen in Group 6, which had the highest proportion of PCB 153. (ABSTRACT TRUNCATED).
 ...
PMID:Toxicology and carcinogenesis studies of a binary mixture of 3,3',4,4',5-pentachlorobiphenyl (PCB 126) (Cas No. 57465-28-8) and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) (CAS No. 35065-27-1) in female Harlan Sprague-Dawley rats (gavage studies). 1716 Jan 4

Although they have several important limitations primary human hepatocytes still represent the in vitro gold standard model for xenobiotic metabolism and toxicity studies. The large use of human liver cell lines either from tumoral origin or obtained by oncogenic immortalisation is prevented by the loss of various liver-specific functions, especially many cytochrome P450 (CYP)-related enzyme activities. We review here recent results obtained with a new human hepatoma cell line, named HepaRG, derived from a human hepatocellular carcinoma. These cells exhibit unique features: when seeded at low density they acquire an elongated undifferentiated morphology, actively divided and after having reached confluency formed typical hepatocyte-like colonies surrounded by biliary epithelial-like cells. Moreover contrary to other human hepatoma cell lines including HepG2 cells, HepaRG cells express various CYPs (CYP1A2, 2B6, 2C9, 2E1, 3A4) and the nuclear receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR) at levels comparable to those found in cultured primary human hepatocytes. They also express various other functions such phase 2 enzymes, apical and canalicular ABC transporters and basolateral solute carrier transporters, albumin, haptoglobin as well as aldolase B that is a specific marker of adult hepatocytes. HepaRG cells could represent a surrogate to primary human hepatocytes for xenobiotic metabolism and toxicity studies and even more, a unique model system for analysing genotoxic compounds.
 ...
PMID:The human hepatoma HepaRG cells: a highly differentiated model for studies of liver metabolism and toxicity of xenobiotics. 1724 19


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>