Project description:Many innovative techniques and scientific improvements are available to tackle societal concerns, like public health safety and confining the risk of cancerous exposure to chemicals, but have not been thoroughly tested and implicated yet. We investigated if microRNA and mRNA transcription profiles can be implemented in a short-term carcinogen classifier assay. Our study is additionally focusing on the drawbacks of present-day carcinogen screening strategies and also aims to contribute to a more ethical approach towards animal use and welfare within risk assessment. Since current in vitro and in silico assays are still not able to mimic the in vivo situation accurately we set out to develop an alternative short-term in vivo assay. Five genotoxic, seven non-genotoxic and five non-carcinogen exposure studies were used to investigate if murine hepatic microRNA and mNA profiles after 7-day exposure are suitable tools to classify carcinogens. Classification analyses showed that a small transcript set, consisting of both microRNA and mRNA, is able to classify the genotoxic, non-genotoxic and non-carcinogens tested with 100% accuracy. The results indicate that microRNAs have the potential to be used as transcriptional classifiers and that a short-term transcriptional classifier assay in mice can be a powerful tool in carcinogenicity risk assessment. Since current in vitro and in silico assays are still not able to mimic the in vivo situation accurately we set out to develop an alternative short-term in vivo assay. Five genotoxic, seven non-genotoxic and five non-carcinogen exposure studies were used to investigate if murine hepatic microRNA and mNA profiles after 7-day exposure are suitable tools to classify carcinogens. Classification analyses showed that a small transcript set, consisting of both microRNA and mRNA, is able to classify the genotoxic, non-genotoxic and non-carcinogens tested with 100% accuracy. The results indicate that microRNAs have the potential to be used as transcriptional classifiers and that a short-term transcriptional classifier assay in mice can be a powerful tool in carcinogenicity risk assessment.

Project description:Gender effects in the incidence of childhood cancers have been described but the aetiology still needs to be fully examined. Given the latent period of e.g. leukemia, its very early onset in childhood might indicate the foetal period as a critical period. We consequently hypothesize that gender-specific differences in childhood cancer incidence (males have a much higher incidence of leukaemia and lymphomas) may be due to gender-specific responses to exposure to environmental carcinogens in utero. We considered that whole genome transcriptomics analysis in cord blood may provide mechanistic insight into possible gender-specific effects of carcinogen exposure in utero. Thus, the objective of the current study was to investigate whether transcriptomic responses to dietary genotoxic and non-genotoxic carcinogens (i.e. acrylamide and endocrine disruptors) as analyzed in umbilical cord blood samples, demonstrate gender-specific mechanisms-of-action relevant for chemical carcinogenesis. For internal exposure assessment, the CALUXM-BM-. assay was applied for measuring dioxin(-like), androgen(-like) and estrogen(-like) exposure, and acrylamide-hemoglobin adduct levels were determined by mass spectrometry. To link gene expression to an established phenotypic biomarker of cancer risk, micronuclei frequencies were investigated in T-lymphocytes. While exposure levels did not differ significantly between sexes at birth, important gender-specific differences were observed in gene expressions associated with these exposures. These genes appeared linked with cell cycle-related processes and general cellular processes such as (post) translation, as well as with immune-related pathways. Moreover, oppositely correlating leukemia and lymphoma genes between male and female newborns were identified in relation to the different biomarkers of exposure which might be relevant to male-specific predisposition to develop these cancers in childhood. This study reveals different transcriptomic responses to environmental carcinogens between the sexes In particular, male-specific TNF-alpha-NF-kB signaling upon dioxin exposure and activation of the Wnt pathway in boys upon acrylamide exposure might represent possible mechanistic explanations for the male predominance in the incidence of childhood leukemia. Umbilical cord blood samples were collected immediately after birth from the cord vein of 45 male and 66 female babies whose mothers participated in the Norwegian BraMat cohort. For analyses, each individual cord blood sample was labelled by means of Cyanine-5 and competitively hybridized against a common reference sample (pooled RNA cord blood samples, labelled with Cyanine-3) onto Agilent 4x44k human oligonucleotide microarrays (Agilent Technologies, Palo Alto, CA, USA) according to the manufacturerM-bM-^@M-^Ys instructions.

Project description:Many innovative techniques and scientific improvements are available to tackle societal concerns, like public health safety and confining the risk of cancerous exposure to chemicals, but have not been thoroughly tested and implicated yet. We investigated if microRNA and mRNA transcription profiles can be implemented in a short-term carcinogen classifier assay. Our study is additionally focusing on the drawbacks of present-day carcinogen screening strategies and also aims to contribute to a more ethical approach towards animal use and welfare within risk assessment. Since current in vitro and in silico assays are still not able to mimic the in vivo situation accurately we set out to develop an alternative short-term in vivo assay. Five genotoxic, seven non-genotoxic and five non-carcinogen exposure studies were used to investigate if murine hepatic microRNA and mNA profiles after 7-day exposure are suitable tools to classify carcinogens. Classification analyses showed that a small transcript set, consisting of both microRNA and mRNA, is able to classify the genotoxic, non-genotoxic and non-carcinogens tested with 100% accuracy. The results indicate that microRNAs have the potential to be used as transcriptional classifiers and that a short-term transcriptional classifier assay in mice can be a powerful tool in carcinogenicity risk assessment. Since current in vitro and in silico assays are still not able to mimic the in vivo situation accurately we set out to develop an alternative short-term in vivo assay. Five genotoxic, seven non-genotoxic and five non-carcinogen exposure studies were used to investigate if murine hepatic microRNA and mNA profiles after 7-day exposure are suitable tools to classify carcinogens. Classification analyses showed that a small transcript set, consisting of both microRNA and mRNA, is able to classify the genotoxic, non-genotoxic and non-carcinogens tested with 100% accuracy. The results indicate that microRNAs have the potential to be used as transcriptional classifiers and that a short-term transcriptional classifier assay in mice can be a powerful tool in carcinogenicity risk assessment. [mRNA profling] 96 hepatic samples in total, 8 control untreated samples, replicates per treated group n=4-6

Project description:N-nitroso compounds (NOC) are genotoxic compounds and animal carcinogens, and may play a role in human cancer development. Since the gastro-intestinal tract is an important route of exposure, we hypothesize that NOC exposure targets genetic processes relevant in colon carcinogenesis. To investigate this, we analysed the transcriptomic effects of genotoxic concentrations of two nitrosamides, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG, 1ÂµM) and N-methyl-N-nitrosurea (MNU, 1mM), and four nitrosamines, N-nitrosodiethylamine (NDEA, 50mM), N-nitrosodimethylamine (NDMA, 100mM), N-nitrosopiperidine (NPIP, 40mM), and N-nitrosopyrrolidine (NPYR, 100mM), in the human colon carcinoma cell line Caco-2. Gene Ontology gene group, consensus motif gene group and biological pathway analysis revealed that nitrosamides had little effect on gene expression after 24 hours of exposure, whereas nitrosamines had a strong impact on the transcriptomic profile. Analyses showed modifications of cell cycle regulation and apoptosis pathways for nitrosamines which was supported by flow cytometric analysis. We found additional modifications in gene groups and pathways of oxidative stress and inflammation, which suggest an increase in oxidative stress and pro-inflammatory immune response upon nitrosamine exposure, although less distinct for NDMA. Furthermore, NDEA, NPIP and NPYR most strongly affected several developmental motif gene groups and pathways, which may influence developmental processes. Many of these pathways and gene groups are implicated in the carcinogenic process and their modulation by nitrosamine exposure may therefore influence the development of colon cancer. In summary, our study has identified pathway modifications in human colon cells which may be associated with cancer risk of nitrosamine exposure in the human colon. Keywords: Comparison of genome-wide gene expression between different conditions The study investigated differential gene expression in Caco-2 cell line mRNA following 24 hours of exposure to six different N-nitroso compounds. Four biological replicates per sample compound. One compound per array, hybridized against vehicle control. Dye-swap between biological replicates 1 and 2, and 3 and 4.

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Transcriptomic fingerprints in human peripheral blood mononuclear cells indicative of genotoxic and non-genotoxic carcinogenic exposure

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