• Molecular & Cellular Toxicology
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• v.5 no.1
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• pp.88-92
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• 2009

The effect of Chlorella vulgaris (CV) on the urinary excretion of di-ortho PCB congeners (PCB-138, -153) was investigated. Sprague-Dawley rats (6-weeks-old, n=10 rats/group) were randomly divided into one control (0CV) or 2% CV (2CV) or 5% CV (5CV) or 10% CV (10CV) groups, respectively. Composition of normal and chlorella meal-based diet were made up of 30% casein, 15% cornstarch, 50% sucrose, 5% cellulose, 5% coconut oil, 3.5% mineral mixture, 1 % vitamin mixture. All rats had free access to water and diet for 4 weeks. A significant increase in both PCB 138 and 153 in urinary level was detected in CV fed groups, 540% and 167% for 2CV, 155% and 89% for 5CV, 114% and 144% for 10CV group, respectively, when compared with their controls. These findings suggest that CV may have potential to eliminate body burden levels of dioxin-like PCB compounds.

• Molecular & Cellular Toxicology
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• v.5 no.4
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• pp.335-345
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• 2009

A major source of paeoniflorin (PF) which was from the Paeonia lactiflora root, has been used as a herbal medicine in East Asia for its antiallergic, antiinflammatory, and immunoregulatory effects. However, only few details are known about the mechanism of apoptosis induced by this compound. The present study was undertaken to further elucidate the molecular mechanism of apoptosis and the changes of gene expression elicited by PF using DNA microarrays and computational gene-expression analysis tools in human leukemia U937 cells. A comparative global transcription analysis between treatment with PF and anisomycin (AM) that induces apoptosis in U937 cells revealed that c-Jun-$NH_2$-kinase (JNK) pathway related genes were less expressed in PF-treated cells. Elucidation of the mechanisms by which PF conducts its anti-cancer activities through comparative analysis of the gene expression is necessary to provide a solid foundation for its use as a promising agent in prevention and treatment strategies.

• Molecular & Cellular Toxicology
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• v.5 no.4
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• pp.283-290
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• 2009

Differential gene expression profiling was performed in the hepatic tissue of marine medaka fish (Oryzias javanicus) after exposure to benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon (PAH), by heterologous hybridization using a medaka cDNA microarray. Thirty-eight differentially expressed candidate genes, of which 23 were induced and 15 repressed (P<0.01), were identified and found to be associated with cell cycle, development, endocrine/reproduction, immune, metabolism, nucleic acid/protein binding, signal transduction, or non-categorized. The presumptive physiological changes induced by BaP exposure were identified after considering the biological function of each gene candidate. The results obtained in this study will allow future studies to assess the molecular mechanisms of BaP toxicity and the development of a systems biology approach to the stress biology of organic chemicals.

• Molecular & Cellular Toxicology
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• v.3 no.1
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• pp.11-18
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• 2007

Mechanisms of insecticide resistance found in insects may include three general categories. Modified behavioral mechanisms can let the insects avoid the exposure to toxic compounds. The second category is physiological mechanisms such as altered penetration, rapid excretion, lower rate transportation, or increased storage of insecticides by insects. The third category relies on biochemical mechanisms including the insensitivity of target sites to insecticides and enhanced detoxification rate by several detoxifying mechanisms. Insecticides metabolism usually results in the formation of more water-soluble and therefore more readily eliminated, and generally less toxic products to the host insects rather than the parent compounds. The representative detoxifying enzymes are general esterases and monooxygenases that catalyze the toxic compounds to be more water-soluble forms and then secondary metabolism is followed by conjugation reactions including those catalyzed by glutathione S-transferases (GSTs). However, a change in the resistant species is not easily determined and the levels of mRNAs do not necessarily predict the levels of the corresponding proteins in a cell. As genomics understands the expression of most of the genes in an organism after being stressed by toxic compounds, proteomics can determine the global protein changes in a cell. In this present review, it is suggested that the environmental proteomic application may be a good approach to understand the biochemical mechanisms of insecticide resistance in insects and to predict metabolomic changes leading to physiological changes of the resistant species.

• Molecular & Cellular Toxicology
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• v.3 no.1
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• pp.60-67
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• 2007

Gentamicin is a broad-spectrum aminoglycoside antibiotic used in the treatment of bacterial infection. Although side effects of gentamicin such as nephrotoxicity and ototoxicity have been investigated, the information on the hepatic effects of gentamicin is still limited. In the present study, gene expression profiles were analyzed in the liver of gentamicin treated mice using Affymetrix GeneChip$^{(R)}$ Mouse Expression 430A 2.0 Array. Totally, 400 genes were identified as being either up- or down-regulated over 1.5-fold changes (P<0.01) in the liver of gentamicin treated mice. Among these deregulated genes, 16 up-regulated genes mainly involved in transport (Kif5b, Pex14, Rab14, Clcn3, and Necap1) and 20 down-regulated genes involved in lipid and other metabolisms (Hdlbp, Gm2a, Uroc1, and Dak) were selected using k-means clustering algorithm. The functional classification of differentially expressed genes represented that several stress-related genes were regulated in the liver by gentamicin treatment. This data may contribute in understanding the molecular mechanism in the liver of gentamicin treated mice.

• Molecular & Cellular Toxicology
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• v.3 no.1
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• pp.31-35
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• 2007

Hesperidin, known as a flavonoid constituent of citrus, has been known to reduce the proliferation of several cancer cells. We investigated whether hesperidin-induced cell death on SNU-668, human gastric cancer cells. The cytotoxicity of hesperidin on SNU-668 cells was determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay at the concentration of 1, 10, 50, and 100 ${\mu}M$. Cell viability by hesperidin was 53.18$\pm$2.85% of control value at 100 ${\mu}M$. The cell death by hesperidin showed apoptotic features, which were confirmed using a combination of 4, 6-diamidino-2-phenylindole (DAPI) staining and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay. In the apoptosis-regulating genes, treatment of hesperidin decreased mRNA expression of B-cell CLL/lymphoma 2 (BCL2), whereas expression of BCL2-associated X protein (BAX) was increased. The mRNA expression and the activity of caspase3 (CASP3), a major apoptotic factor, was significantly increased by hesperidin treatment. These results suggest that hesperidin could induce apoptosis through CASP3 activation on SNU-668, human gastric cancer cells.

• Molecular & Cellular Toxicology
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• v.3 no.1
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• pp.68-75
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• 2007

[ $\alpha$ ]-Terpinene has been known as a repellent against the mosquito Culex pipiens pallens Coquillett based on a human forearm bioassay. $\alpha$-Terpinene showed significantly greater repellency than a commercial formulation, N, N-diethyl-m-methylbenzamide (deet). In this study, skin and eye sensitivity of $\alpha$-terpinene (2%) was examined with bioassays using white New Zealand rabbits. There were somewhat gross and histological changes observed in these treatments. Eye irritancy assays examined gross changes to cornea, iris and conjuctiva, and histological changes to smear of ocular discharge and eye tissue. Treated rabbits were divided into two cohorts, a saline washed cohort (W) or a non-washed cohort (NW). Opacity of cornea and redness, chemosis and discharge of conjuctiva were observed in both cohorts, but disappeared within 4 and 10 days in W and NW, respectively. Main components of ocular discharges were fibrin, epithelial or epitheloid cells, lymphoid cells, erythrocytes and granulocytes. These abnormal cellular components disappeared within 4 days and 10 days in W and NW, respectively. No permanent histological differences were observed between the two cohorts. However, severe irritation was determined as 57.2 of I.I.O.I value on the first day after treatment. These findings indicate a spray-type solution containing 2% $\alpha$-terpinene may serve as an alternative mosquito repellent and further studies need to reduce the eye irritation with formulation changes.

• Molecular & Cellular Toxicology
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• v.5 no.3
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• pp.207-215
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• 2009

Despite wide therapeutic use of CpG ODN against infection, allergy and cancer, the safety and toxicity of CpG ODNs were poorly delineated. Thus, we investigated whether optimal dosing of CpG ODN would affect immunotoxicological parameters in NZB/NZW F1 mice. Comparisons were made among control, non-CpG ODN and mouse CpG ODN ($10{\mu}g$)-treated groups for 4 weeks. To gauge the immunotoxicity of CpG ODNs, we measured nonspecific parameters, degree of lupus nephritis, proteinuria, or autoantibody, and cytokine expression in mRNA level of lymphocytes. We found that there were no significant differences among groups in nonspecific immunotoxicological profiles and in evaluation profiles of glomerulonephritis. However, titer of anti-dsDNA and anti-cardiolipin antibodies in mouse CpG ODN group rose three or eight-fold higher than in control group. Collectively, CpG ODN might be clinically less immunotoxic in terms of clinical profiles in lupus-prone NZB/NZW F1 mice, in spite of high autoantibody titer in CpG ODN treated groups.

• Molecular & Cellular Toxicology
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• v.5 no.3
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• pp.265-271
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• 2009

Concentrations of industrial, agricultural and natural chemicals have been increasing in secondary effluents without their combined sub-lethal effects having been elucidated. In this study, two assays (the comet and acetylcholinesterase assays) were combined to evaluate the genotoxic and neurotoxic effects of effluent from the Noksan wastewater treatment plant (WWTP) on two local marine fish species (flounder and sea eel). The fish were exposed to WWTP secondary effluent that had been diluted with filtered seawater to final concentrations of 1%, 10% and 50%. Analysis of fish samples collected 3 and 5 days after exposure showed that DNA damage occurred in flounder exposed to 50% effluent and in sea eels exposed to 10% or 50% effluent. Furthermore, it was found that acetylcholinesterase (EC:3.1.1.7, AChE) activity decreased in both species when exposed to 10% effluent, indicating the presence of large amounts of genotoxic and neurotoxic chemicals in the effluent. Our results indicate that the comet and AChE assays are promising tools for biomonitoring of secondary effluents.

• Molecular & Cellular Toxicology
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• v.3 no.3
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• pp.159-164
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• 2007

Stimulation of epidermal growth factor receptor (EGFR) is essential in signaling pathway of tumor cells. Thus, EGFR has intensely studied as an anticancer target. We developed hologram quantitative structure activity relationship (HQSAR) models for data set which consists of tricyclic azepine derivatives showing inhibitory activities for EGFR. The optimal HQSAR model was generated with fragment size of 6 to 7 while differentiating fragments having different atom and connectivity. The model showed cross-validated $q^2$ value of 0.61 and non-cross-validated $r^2$ value of 0.93. When the model was validated with an external set excluding one outlier, it gave predictive $r^2$ value of 0.43. The contribution maps generated from this model were used to interpret the atomic contribution of each atom to the overall inhibition activity. This can be used to find more efficient EGFR inhibitors.