• Molecular & Cellular Toxicology
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• v.1 no.4
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• pp.275-280
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• 2005

Carbon tetrachloride ($CCl_4$) is well known hepatotoxicant. Its overdose cause severe centrilobular hepatic necrosis in human and experimental animals. We administered $CCl_{4}$ at low (0.2 mL/kg p.o.) and high (2 mL/kg p.o.) doses to mice. Mice were sacrificed at 24 h after administration. We evaluated liver toxicity by serum AST and ALT level and by microscopic observation. Using cDNA chip, we conducted gene expression analysis in liver. Mean serum activities of the hepatocellular leakage enzymes, ALT and AST, were significantly increased compare to control, respectively, in the low and high dose groups. H&E evaluation of stained liver sections revealed $CCl_{4}-related$ histopathological findings in mice. Moderate centrilobular hepatocellular necrosis was present in all $CCl_{4}$ treated mice. We found that gene expression pattern was very similar between low and high dose group. However, some stress related genes were differently expressed. These results could be a molecular signature for the degree of liver injury. Our data suggest that the degree of severity could be figure out by gene expression profiling.

• Molecular & Cellular Toxicology
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• v.1 no.4
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• pp.230-236
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• 2005

Formaldehyde is a common environmental contaminant found in tobacco smoke, paint, garments, diesel and exhaust, and medical and industrial products. Formaldehyde has been considered to be potentially carcinogenic, making it a subject of major environmental concern. However, only a little information on the mechanism of immunological sensitization and asthma by this compound has been known. So, we performed with Jurkat cell line, a human T lymphocyte, to assess the induction of DNA damage and to identify the DEGs related to immune response or toxicity by formaldehyde. In this study, we investigated the induction of DNA single strand breaks by formaldehyde using single cell gel electrophoresis assay (comet assay). And we compared gene expression between control and formaldehyde treatment to identify genes that are specifically or predominantly expressed by employing annealing control primer (ACP)-based $GeneFishing^{TM}$ method. The cytotoxicity ($IC_{30}$) of formaldehyde was determined above the 0.65 mM in Jurkat cell in 48 h treatment. Based on the $IC_{30}$ value from cytotoxicity test, we performed the comet assay in this concentration. From these results, 0.65 mM of formaldehyde was not revealed significant DNA damages in the absence of S-9 metabolic activation system. And the one differentially expressed gene (DEG) of formaldehyde was identified to zinc finger protein 292 using $GeneFishing^{TM}$ method. Through further investigation, we will identify more meaningful and useful DEGs on formaldehyde, and then can get the information on the associated mechanism and pathway with immune response or other toxicity by formaldehyde exposure.

• Molecular & Cellular Toxicology
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• v.2 no.3
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• pp.166-169
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• 2006

Accumulated evidences have established that aberrant regulation of histone deacetylases (HDACs) is one of major causes for development of human malignancies. Mammalian HDACs can be divided into three subclasses consisting of 11 homologous of HDACs and 7 of sirtuins, but little is known about HDAC2 causes for carcinogenesis in solid tumors. Here, in order to investigate the roles of HDAC2 in carcinogenesis of liver cancer progression, we analyzed the expression of HDAC2 in 62 human hepatocellular carcinomas by utilizing Immunohistochemistry. Moderate to strong expression of HDAC2 was found in 54 (87%) out of total 62 tumors. The majority of positive tumors were detected in nucleous, but normal hepatocytes did not express of HDAC2 or showed weak positive staining. Interestingly, we were also noted that HDAC2 expression was appeared to be associated with aggressiveness of the tumors by the fact that HDAC2 expression was observed with significances in high grade tumors (Edmonson grade II, III). Taken together, we found the aberrant expression of HDAC2 in hepatocellular carcinomas, and this suggests that HDAC2 may play an important role in the development of liver cancer.

• Molecular & Cellular Toxicology
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• v.3 no.2
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• pp.132-136
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• 2007

Zinc is essential metal and plays a role in a wide variety of physiological and biochemical processes. Prostate gland contains high level of zinc, generally 3-10 folds higher than other organs. Prostatic zinc uptake is resulted from the existence of zinc transporter (ZnT) protein families in membrane. In this study, we investigated the difference of zinc uptake efficiency of zinc-aspartate complex (Zn-Asp) into various organs compared with $ZnSO_4$. We observed that Plasma zinc concentration in both $ZnSO_4$ and Zn-Asp administrated group was increased progressively following administration, and reached a peak level at 2 hr. The increasing pattern of zinc concentration was similar to each groups, however the zinc concentration of Zn-Asp administrated group was higher than that of $ZnSO_4$ administrated group. We found that prostatic zinc level of Zn-Asp administrated group was higher than $ZnSO_4$ administrated group, and was increased approximately $\sim$2.7 fold and $\sim$4.2 fold at 4 and 8 hr after administration. From these observations, we suggest than Zn-Asp has high uptake efficiency of zinc into the prostate gland. Therefore, Zn-Asp is potentially useful treatment of many prostatic diseases.

• Molecular & Cellular Toxicology
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• v.3 no.2
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• pp.85-89
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• 2007

Efficient gene delivery to specific tissues, such as inflammatory and cancerous tissues, is currently a major concern in disease treatment. The human transferrin receptor (hTR) has been detected in the synovium and fibroblast-like synoviocytes (FLS), which raises the possibility that expression of hTR is associated with the pathogenesis of rheumatoid arthritis (RA). To investigate whether the hTR is a useful target for gene transduction into the FLS of RA patients, recombinant adenoviruses with wildtype fiber (AdLac) and transferrin peptide-tagged fiber (Tf-AdLac) were used. The hTR expression level in FLS was notably increased by basic fibroblast growth factor (bFGF). Gene transduction to FLS was significantly higher by the hTR-targeted adenovirus than by the AdLac adenovirus, and treatment of the FLS with bFGF resulted in increased gene transduction by Tf-AdLac. Taken together, these data support Tf-AdLac as a new strategy for gene transduction in the treatment of RA patients.

• Molecular & Cellular Toxicology
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• v.3 no.2
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• pp.127-131
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• 2007

Chronic treatment with olanzapine (OLZ), an atypical antipsychotic drug, is associated with the adverse effects of weight gain, hyperglycemia and/or hypertriglyceridemia. Green tea or epigallocatechin gallate (EGCG), one of the most abundant green tea polyphenols, significantly reduces or prevents an increase in glucose levels, lipid markers and/or body weight. We hypothesized that combined treatment with OLZ and green tea extract (GTE) or EGCG may prevent body weight gain and increase of the lipid markers. ICR male mice weighing an average of 30.51 g (n=32) at the beginning of the experiment were used. OLZ, OLZ+GTE and OLZ+EGCG were administered for 27 d in the drinking water, and then the levels of fasting glucose, nitric oxide (NO), and a typical lipid marker triglyceride (TG) were determined in plasma. The body weight and food intake were also compared. The chronic treatment of OLZ increased the average body weight compared with that of controls. In the presence of GTE or EGCG, the OLZ-induced increase in body weight was significantly prevented. Furthermore, in the OLZ group, the plasma levels of glucose, NO and TG were significantly increased, whereas GTE or EGCG prevented these increases. These results implicate that OLZ may induce systematic inflammatory reaction, and suggest that GTE or EGCG can protect against OLZinduced weight gain, hyperglycemia and hypertriglyceridemia.

• Molecular & Cellular Toxicology
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• v.3 no.2
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• pp.137-144
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• 2007

The mechanism of cytotoxicity of doxifluridine, a prodrug fluorouracil (5-FU), has been ascribed to the misincorporation of fluoropyrimidine into RNA and DNA and to the inhibition of the nucleotide synthetic enzyme thymidylate synthase. Increased understanding of the mechanism of 5-FU has led to the development of strategies that increases its anticancer activity or predicts its sensitivity to patients. Using GeneChip?? Rhesus Macaque Genome arrays, we analyzed gene expression profiles of doxifluridine after two weeks repeated administration in cynomolgus monkey. Kegg pathway analysis suggested that cytoskeletal rearrangement and cell adhesion remodeling were commonly occurred in colon, jejunum, and liver. However, expression of genes encoding extracellular matrix was distinguished colon from others. In colon, COL6A2, COL18A1, ELN, and LAMA5 were over-expressed. In contrast, genes included in same category were down-regulated in jejunum and liver. Interestingly, MMP7 and TIMP1, the key enzymes responsible for ECM regulation, were overexpressed in colon. Several studies were reported that both gene reduced cell sensitivity to chemotherapy-induced apoptosis. Therefore, we suggest they have potential as target for modulation of 5-FU action. In addition, the expression of genes which have been previously known to involve in 5-FU pathway, were examined in three organs. Particularly, there were more remarkable changes in colon than in others. In colon, ECGF1, DYPD, TYMS, DHFR, FPGS, DUT, BCL2, BAX, and BAK1 except CAD were expressed in the direction that was good response to doxifluridine. These results may provide that colon is a prominent target of doxifluridine and transcriptional profiling is useful to find new targets affecting the response to the drug.

• Molecular & Cellular Toxicology
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• v.4 no.4
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• pp.323-330
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• 2008

Surrogate tissue analysis incorporating -omics technologies has emerged as a potential alternative method for evaluating toxic effect of the tissues which are not accessible for sampling. Among the recent applications, blood including whole blood, peripheral blood lymphocytes and peripheral blood mononuclear cells (PBMCs) was suggested as a suitable surrogate tissue in determining toxicant exposure and effect at the pre- or early clinical stage. In this application, we investigated transcriptomic profiles in astemizole treated Cynomolgus monkey's PBMCs. PBMCs were isolated from 4-6 years old male monkeys at 24 hr after administration45 Helvetica Light (10 mg/kg, 30 mg/kg). Gene expression profiles of astemizole treated monkey's PBMCs were determined using Affymetrix $GeneChip^{(R)}$ Human Genome U133 plus 2.0 arrays. The expression levels of 724 probe sets were significantly altered in PBMCs at 10 or 30 mg/kg after astemizole administration following determination of paired t-test using statistical criteria of ${\geq}$$1.5-fold changes at P<0.05. Gene expression patterns in PBMCs showed a considerable difference between astemizole 10 and 30 mg/kg administration groups in spite of an administration of the same chemical. However, close examination using Ingenuity Pathway Analysis (IPA) software revealed that several gene sets related to cardiotoxicity were deregulated at astemizole 10 and 30 mg/kg administration groups. The deregulation of cardiac hypertrophy related genes such as TXN, GNAQ, and MAP3K5 was observed at 10 mg/kg group. In astemizole 30 mg/kg group, genes involved in cardiotoxicity including cardiac necrosis/cell death, dilation, fibrosis, and hypertrophy were also identified. These results suggest that toxicogenomic approach using PBMCs as surrogate tissues will contribute to assess toxicant exposures and identify biomarkers at the pre-clinical stage.

• Molecular & Cellular Toxicology
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• v.4 no.4
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• pp.338-347
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• 2008

Yeast RAD2, a yeast homolog of human XPG gene, is an essential element of nucleotide excision repair (NER), and its deletion confers UV sensitivity and NER deficiency. 6-Azauracil (6AU) sensitivity of certain rad2 mutants revealed that RAD2 has transcription elongation function. However, the fundamental mechanism by which the rad2 mutations confer 6AU sensitivity was not clearly elucidated yet. Using an insertional mutagenesis, PUF4 gene encoding a yeast pumilio protein was identified as a deletion suppressor of rad2${\Delta}$ 6AU sensitivity. Microarray analysis followed by confirmatory RT-qPCR disclosed that RAD2 and PUF4 regulated expression of HPT1 and URA3. Overexpression of HPT1 and URA3 rescued the 6AU sensitivity of rad2${\Delta}$ and puf4${\Delta}$ mutants. These results indicate that 6AU sensitivity of rad2 mutants is in part ascribed to impaired expression regulation of genes in the nucleotide metabolism. Based on the results, the possible connection between impaired transcription elongation function of RAD2/XPG and Cockayne syndrome via PUF4 is discussed.

• Molecular & Cellular Toxicology
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• v.4 no.4
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• pp.360-365
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• 2008

In the last several years, studies on the association of oxidative stress damage with exposure in the work place have been conducted. Xenobiotics create an imbalance of the homeostasis between oxidant molecules and antioxidant defense. By monitoring oxidative stress biomarkers, information was obtained on damages induced by oxidative stress and the toxicity of xenobiotics. In the present study, a Job Exposure Matrix (JEM) was constructed using the data from the Working Environment Measurement (WEM) of painters in the shipyard industry from the past 3 years to assess the exposure status. Additionally, by measuring the concentration of urinary malondialdehyde (MDA), the effect of lipid peroxidation was examined. The subjects consisted of 68 workers who were exposed to mixed organic solvents in the painting process and 25 non-exposure controls. The exposure indices of the exposure groups were significantly different (sprayer: 0.83, touchup: 0.54, assistant: 0.13, P<0.05). The urinary MDA concentration of the exposure group was 48.60${\pm}$ 39.23 ${\mu}mol$/mol creatinine, which was significantly higher than 18.03${\pm}$16.33 ${\mu}mol$/mol creatinine of the control group (P<0.05). From the multiple regression analysis of urinary MDA, the regression coefficient for exposure grade was statistically significant. In future studies, evaluation of the antioxidant levels of subjects should be performed simultaneously with quantitative exposure measurements.