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Effects of selected food phytochemicals in reducing the toxic actions of TCDD and p,p'-DDT in U937 macrophages.

Sciullo EM, Vogel CF, Wu D, Murakami A, Ohigashi H, Matsumura F - Arch. Toxicol. (2010)

Bottom Line: We tested auraptene on DDT-induced reactive oxygen species (ROS) formation in U937 macrophages and found that auraptene is a powerful agent antagonizing this action of DDT.To confirm the significance of these actions of zerumbone and auraptene at the cellular level, we assessed their influence on TCDD-induced apoptosis resistance in intact U937 macrophages and found that they are capable of reversing this action of TCDD.In conclusion, zerumbone and auraptene were identified to be the most effective agents in protecting U937 macrophages from developing these cell toxic effects of TCDD and DDT.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Toxicology, University of California Davis, 3792 Old Davis Rd, Davis, CA 95616, USA.

ABSTRACT
To assess the effectiveness of selected food phytochemicals in reducing the toxic effects of the environmental toxicants, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and p,p'-DDT (DDT), we tested the potencies of auraptene, nobiletin, zerumbone, and (±)-13-hydroxy-10-oxo-trans-11-octadecenoic acid (13-HOA) in reversing the inflammatory action of these toxicants in U937 human macrophages. Using quantitative RT-PCR as the initial screening assay, we identified antagonistic actions of zerumbone and auraptene against the action of TCDD and DDT in up-regulating the mRNA expressions of COX-2 and VEGF. The functional significance of the inhibitory action of zerumbone on COX-2 expression was confirmed by demonstrating its suppression of TCDD-induced activation of COX-2 gene expression in mouse MMDD1 cells. We tested auraptene on DDT-induced reactive oxygen species (ROS) formation in U937 macrophages and found that auraptene is a powerful agent antagonizing this action of DDT. To confirm the significance of these actions of zerumbone and auraptene at the cellular level, we assessed their influence on TCDD-induced apoptosis resistance in intact U937 macrophages and found that they are capable of reversing this action of TCDD. In conclusion, zerumbone and auraptene were identified to be the most effective agents in protecting U937 macrophages from developing these cell toxic effects of TCDD and DDT.

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Assessment of inhibitory action of zerumbone on the function of mouse COX-2 gene activation, as measured in the mouse MMDD1 model cells. a Cells were transiently transfected with the pCOX-2-Luc reporter plasmid using the luciferase assay. The longer plasmid contains the near full length mouse COX-2 promoter, and the shorter plasmid contains only the C/EBP response element that is adjacent to the start codon. MMDD1 cells were pre-treated with 2 μM zerumbone for 1 h, followed by 10 nM TCDD treatment for 20 h. *Significantly different from control  P ≤ 0.01. a Significant lower than control P ≤ 0.01. b Significantly lower than TCDD treatment alone  P ≤ 0.01. b DNA binding activity of nuclear proteins from U937 macrophages to the C/EBP element of the COX-2 promoter. Cells were treated with 10 nM TCDD or 0.1% DMSO (Vehicle control) for 3 h. Antibodies for C/EBPα, β, and δ isoforms were used in supershift analysis. A 100-fold excess of unlabeled oligonucleotide was added (Lane 6). C) DNA binding activity of nuclear proteins from U937 macrophages to the C/EBP element of the COX-2 promoter. Cells were treated with 10 nM TCDD in absence (lane 2) or presence (lane 4) of 10 μM zerumbone for 3 h
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Fig3: Assessment of inhibitory action of zerumbone on the function of mouse COX-2 gene activation, as measured in the mouse MMDD1 model cells. a Cells were transiently transfected with the pCOX-2-Luc reporter plasmid using the luciferase assay. The longer plasmid contains the near full length mouse COX-2 promoter, and the shorter plasmid contains only the C/EBP response element that is adjacent to the start codon. MMDD1 cells were pre-treated with 2 μM zerumbone for 1 h, followed by 10 nM TCDD treatment for 20 h. *Significantly different from control P ≤ 0.01. a Significant lower than control P ≤ 0.01. b Significantly lower than TCDD treatment alone P ≤ 0.01. b DNA binding activity of nuclear proteins from U937 macrophages to the C/EBP element of the COX-2 promoter. Cells were treated with 10 nM TCDD or 0.1% DMSO (Vehicle control) for 3 h. Antibodies for C/EBPα, β, and δ isoforms were used in supershift analysis. A 100-fold excess of unlabeled oligonucleotide was added (Lane 6). C) DNA binding activity of nuclear proteins from U937 macrophages to the C/EBP element of the COX-2 promoter. Cells were treated with 10 nM TCDD in absence (lane 2) or presence (lane 4) of 10 μM zerumbone for 3 h

Mentions: To confirm the inhibitory action of zerumbone on COX-2 expression, we tested its effect on the COX-2 gene activation using two COX-2-luciferase reporter plasmids on a kidney tubular epithelial cell model (MMDD1), since the active form of COX enzyme in this cell line mostly consists of COX-2, and since it is known to be very sensitive to the action of TCDD (Dong et al. 2010). The larger plasmid contains a near full length mouse COX-2 promoter ligated to a Luc gene, and the shorter one, in contrast, contains only the short segment of its promoter, which includes the CCAAT/enhancer binding protein (C/EBP) response element that is located close to the start codon. The results summarized in Fig. 3 show that zerumbone is effective in suppressing the COX-2 gene activating function of TCDD in both reporter transfected MMDD1 cell samples.Fig. 3


Effects of selected food phytochemicals in reducing the toxic actions of TCDD and p,p'-DDT in U937 macrophages.

Sciullo EM, Vogel CF, Wu D, Murakami A, Ohigashi H, Matsumura F - Arch. Toxicol. (2010)

Assessment of inhibitory action of zerumbone on the function of mouse COX-2 gene activation, as measured in the mouse MMDD1 model cells. a Cells were transiently transfected with the pCOX-2-Luc reporter plasmid using the luciferase assay. The longer plasmid contains the near full length mouse COX-2 promoter, and the shorter plasmid contains only the C/EBP response element that is adjacent to the start codon. MMDD1 cells were pre-treated with 2 μM zerumbone for 1 h, followed by 10 nM TCDD treatment for 20 h. *Significantly different from control  P ≤ 0.01. a Significant lower than control P ≤ 0.01. b Significantly lower than TCDD treatment alone  P ≤ 0.01. b DNA binding activity of nuclear proteins from U937 macrophages to the C/EBP element of the COX-2 promoter. Cells were treated with 10 nM TCDD or 0.1% DMSO (Vehicle control) for 3 h. Antibodies for C/EBPα, β, and δ isoforms were used in supershift analysis. A 100-fold excess of unlabeled oligonucleotide was added (Lane 6). C) DNA binding activity of nuclear proteins from U937 macrophages to the C/EBP element of the COX-2 promoter. Cells were treated with 10 nM TCDD in absence (lane 2) or presence (lane 4) of 10 μM zerumbone for 3 h
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Related In: Results  -  Collection

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Fig3: Assessment of inhibitory action of zerumbone on the function of mouse COX-2 gene activation, as measured in the mouse MMDD1 model cells. a Cells were transiently transfected with the pCOX-2-Luc reporter plasmid using the luciferase assay. The longer plasmid contains the near full length mouse COX-2 promoter, and the shorter plasmid contains only the C/EBP response element that is adjacent to the start codon. MMDD1 cells were pre-treated with 2 μM zerumbone for 1 h, followed by 10 nM TCDD treatment for 20 h. *Significantly different from control P ≤ 0.01. a Significant lower than control P ≤ 0.01. b Significantly lower than TCDD treatment alone P ≤ 0.01. b DNA binding activity of nuclear proteins from U937 macrophages to the C/EBP element of the COX-2 promoter. Cells were treated with 10 nM TCDD or 0.1% DMSO (Vehicle control) for 3 h. Antibodies for C/EBPα, β, and δ isoforms were used in supershift analysis. A 100-fold excess of unlabeled oligonucleotide was added (Lane 6). C) DNA binding activity of nuclear proteins from U937 macrophages to the C/EBP element of the COX-2 promoter. Cells were treated with 10 nM TCDD in absence (lane 2) or presence (lane 4) of 10 μM zerumbone for 3 h
Mentions: To confirm the inhibitory action of zerumbone on COX-2 expression, we tested its effect on the COX-2 gene activation using two COX-2-luciferase reporter plasmids on a kidney tubular epithelial cell model (MMDD1), since the active form of COX enzyme in this cell line mostly consists of COX-2, and since it is known to be very sensitive to the action of TCDD (Dong et al. 2010). The larger plasmid contains a near full length mouse COX-2 promoter ligated to a Luc gene, and the shorter one, in contrast, contains only the short segment of its promoter, which includes the CCAAT/enhancer binding protein (C/EBP) response element that is located close to the start codon. The results summarized in Fig. 3 show that zerumbone is effective in suppressing the COX-2 gene activating function of TCDD in both reporter transfected MMDD1 cell samples.Fig. 3

Bottom Line: We tested auraptene on DDT-induced reactive oxygen species (ROS) formation in U937 macrophages and found that auraptene is a powerful agent antagonizing this action of DDT.To confirm the significance of these actions of zerumbone and auraptene at the cellular level, we assessed their influence on TCDD-induced apoptosis resistance in intact U937 macrophages and found that they are capable of reversing this action of TCDD.In conclusion, zerumbone and auraptene were identified to be the most effective agents in protecting U937 macrophages from developing these cell toxic effects of TCDD and DDT.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Toxicology, University of California Davis, 3792 Old Davis Rd, Davis, CA 95616, USA.

ABSTRACT
To assess the effectiveness of selected food phytochemicals in reducing the toxic effects of the environmental toxicants, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and p,p'-DDT (DDT), we tested the potencies of auraptene, nobiletin, zerumbone, and (±)-13-hydroxy-10-oxo-trans-11-octadecenoic acid (13-HOA) in reversing the inflammatory action of these toxicants in U937 human macrophages. Using quantitative RT-PCR as the initial screening assay, we identified antagonistic actions of zerumbone and auraptene against the action of TCDD and DDT in up-regulating the mRNA expressions of COX-2 and VEGF. The functional significance of the inhibitory action of zerumbone on COX-2 expression was confirmed by demonstrating its suppression of TCDD-induced activation of COX-2 gene expression in mouse MMDD1 cells. We tested auraptene on DDT-induced reactive oxygen species (ROS) formation in U937 macrophages and found that auraptene is a powerful agent antagonizing this action of DDT. To confirm the significance of these actions of zerumbone and auraptene at the cellular level, we assessed their influence on TCDD-induced apoptosis resistance in intact U937 macrophages and found that they are capable of reversing this action of TCDD. In conclusion, zerumbone and auraptene were identified to be the most effective agents in protecting U937 macrophages from developing these cell toxic effects of TCDD and DDT.

Show MeSH
Related in: MedlinePlus