Project description:Analysis of gene expression level in a mouse tumorigenic phthalate, DEHP vs non-tumorigenic DNOP. The hypothesis tested in the present study was to identify early key event thresholds related to tumor outcomes in a two-year carcinogenicity bioassay. Our results highlight marked differences in the toxicity profiles of structurally similar phthalates and demonstrate quantitative relationships between early bioindicators and later tumor outcomes. Total RNA obtained from liver samples subjected to 30wk exposures of cont, DEHP, DNOP. Samples processed with Illumina Mouse WG 8-v 2.0 beadarrays. Gene profiles generated for the compounds support observed key events in mode-of-action for these phthalates.
Project description:The goal of this study was to determine short-term key event markers using qualitative and quantitative methods in an established pathway of mouse liver tumorigenesis mediated by peroxisome proliferator-activated receptor alpha (PPARα). a 7-day case study approach was used to determine transcriptional PODs and effect thresholds for early key events in an established MOA for liver tumorigenesis in mice. The target pathway is mediated by peroxisome proliferator-activated receptor alpha (PPARalpha) (Corton et al. 2013). In this study we analyzed three reference phthalates with different levels of receptor activity and liver outcomes at 2 years.
Project description:Analysis of gene expression level in a mouse tumorigenic phthalate, DEHP vs non-tumorigenic DNOP. The hypothesis tested in the present study was to identify early key event thresholds related to tumor outcomes in a two-year carcinogenicity bioassay. Our results highlight marked differences in the toxicity profiles of structurally similar phthalates and demonstrate quantitative relationships between early bioindicators and later tumor outcomes.
Project description:We report the RNAseq-based transcriptome profiles of rat gestation day 20 dam liver, fetal male and female liver, fetal male pituitary, and fetal testis following in utero exposure to either 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or 2,3,7,8-tetrachlorodibenzofuran (TCDF). Two exposure models were examined: 1) pregnant rats exposed to either a dose response series of TCDD or TCDF from gestation day 6 - 20 or 2) pregnant rats exposed to a single dose of TCDD or TCDF on gestation day 15. These data support a mode-of-action for dioxin-induced rat male reproductive toxicity involving key events in both the fetal pituitary (reduced gonadotropin production) and fetal testis (reduced Leydig cell cholesterologenesis and steroidogenesis) which are hypothesized to decrease perinatal Sertoli cell proliferation and culminate in reduced spermatogenesis. The lack of a TCDF effect on proposed key events may be due to a higher rate of metabolic clearance relative to TCDD.
Project description:We reported the hepatic gene expression profiling in male Sprague-Dawley rats treated by different concentrations of perfluorooctanoic acid (PFOA) for 7, 14, and 28 days. We confirmed that PFOA induced liver tumor formation was mainly through the activation of peroxisome proliferator-activated receptor α (PPARα). We identified a panel of 7 genes (Cyp4a1, Nr1d1, Acot2, Vnn, Ehhadh, and Acot1) that might serve as the biomarkers for PPARα activation. We also meausred the apical endpoints of PPARα activation and found a good correlation with the expression level of these biomarker genes. Consitituitive androstane receptor mediated Cyp2b enzymatic activity and gene expression was also upregulated by PFOA in a dose-response manner. On the other hand, acyl hydrocarbon receptor (AhR) target gene Cyp1a2 were significantly downregulated at all time points studied. To our surprise, results of KEGG and Reactome pathway analyses suggested that PFOA did not drive the cell cycles and proliferations in the liver. While some of the DNA replication genes such as Pold2 and Mcm8 were upregulated by PFOA treatment, several key cyclin-dependent cell growth genes, including Ccnd1, Ccne2, Ccnb1, and Ccna2 were all significantly downregulated by PFOA in a dose-dependent manner, especailly at 28 days. Ingenuity Pathway Analysis also indicated that PFOA led to a suppression of liver cancer related pathways at later time points studied. These results suggest that while PFOA clearly induced PPARα activation, the increased cell growth (the second key event in the tumor mode of action), was transient and tightly regulated by feedback mechanisms. Whether such changes will eventually cause the formation of preneoplastic foci and liver tumors in rats remains unclear.
Project description:Analysis of gene expression alterations and RNA splicing events after Ancistrocladinium A treatment of INA-6 multiple myeloma cell line Ancistrocladinium A inan N,C-coupled naphthylisoquinoline alkaloid was analyzed for its ability to act as efficient anti-myeloma agent. The mode of action was unknown. We analyzed the effect of Ancistrocladinium A on the multiple myeloma cell line INA-6 on RNA level and identivied differentially regulated genes on the one hand and splicing events on the other hand gaining a first insight into the mode of action of Ancistrocladinium A.
Project description:2,4-dinitrotoluene (2,4-DNT), a nitroaromatic used in industrial and explosive manufacturing processes, is known to contaminate artillery ranges, demilitarization areas and munitions manufacturing facilities. Previous transcriptomic and lipidomic studies identified energy metabolism as a principle biochemical process affected by 2,4-DNT where up-stream effects on PPARα signaling were hypothesized as themolecular initiating event for these effects. Here, the validity of this hypothetical adverse outcome pathway (AOP) was assessed by testing the hypothesis that 2,4-DNT-induced perturbations in PPARα signaling and resultant downstream deficits in energy metabolism, especially from lipids, would result in organism-level impacts on exercise endurance. PPARα knock-out (-/-) and wild-type (WT) mice were exposed for 14 days to vehicle or 2,4-DNT at a dose (134 mg/kg/day) that did not exhibit overt systemic toxicity. Mice performed an exercise challenge (forced swim) 1 day after the last dose. 2,4-DNT decreased swim times in WT and PPARα (-/-) mice, but the effect was significantly less in PPARα (-/-) mice indicating the critical of PPARα in mediating 2,4-DNT-induced energy metabolism deficits. 2,4-DNT caused down-regulation of transcripts involved in fatty acid metabolism, gluconeogenesis, triacylglycerol catabolism, and the pentose phosphate pathway, and 2,4-DNT treated wild-type mice had decreased serum trigylcerides and increased serum glucose versus 2,4-DNT treated PPARα (-/-) mice. Our results support the hypothesis that 2,4-DNT perturbs PPARα signaling as a molecular initiating event therefore impacting energy metabolism, especially lipid metabolism, producing reduced exercise endurance in mice. RNA was isolated from liver tissue of vehicle or 2,4-DNT treated wild-type or PPARα (-/-) mice (n=6) and RT-PCR performed to analyze genes involved in fatty acid metabolism
Project description:2,4-dinitrotoluene (2,4-DNT), a nitroaromatic used in industrial and explosive manufacturing processes, is known to contaminate artillery ranges, demilitarization areas and munitions manufacturing facilities. Previous transcriptomic and lipidomic studies identified energy metabolism as a principle biochemical process affected by 2,4-DNT where up-stream effects on PPARα signaling were hypothesized as themolecular initiating event for these effects. Here, the validity of this hypothetical adverse outcome pathway (AOP) was assessed by testing the hypothesis that 2,4-DNT-induced perturbations in PPARα signaling and resultant downstream deficits in energy metabolism, especially from lipids, would result in organism-level impacts on exercise endurance. PPARα knock-out (-/-) and wild-type (WT) mice were exposed for 14 days to vehicle or 2,4-DNT at a dose (134 mg/kg/day) that did not exhibit overt systemic toxicity. Mice performed an exercise challenge (forced swim) 1 day after the last dose. 2,4-DNT decreased swim times in WT and PPARα (-/-) mice, but the effect was significantly less in PPARα (-/-) mice indicating the critical of PPARα in mediating 2,4-DNT-induced energy metabolism deficits. 2,4-DNT caused down-regulation of transcripts involved in fatty acid metabolism, gluconeogenesis, triacylglycerol catabolism, and the pentose phosphate pathway, and 2,4-DNT treated wild-type mice had decreased serum trigylcerides and increased serum glucose versus 2,4-DNT treated PPARα (-/-) mice. Our results support the hypothesis that 2,4-DNT perturbs PPARα signaling as a molecular initiating event therefore impacting energy metabolism, especially lipid metabolism, producing reduced exercise endurance in mice. RNA was isolated from liver tissue of vehicle or 2,4-DNT treated wild-type or PPARα (-/-) mice (n=6) and RT-PCR performed to analyze genes involved in fatty acid metabolism