Project description:Genotoxic agents cause cellular DNA damage and stress responses, including transcriptional changes. Here we focused on the early transcriptional responses of human cells to benzo(a)pyrene diol epoxide (BPDE), which causes bulky DNA adduct damage. Human amnion epithelial FL cells were exposed to three doses of BPDE (5, 50, and 500 nM) and the vehicle control DMSO, and differential gene expression profiles were obtained 4 h after exposure using oligonucleotide microarrays followed by validation with quantitative real-time RT-PCR. Compared with a few genes affected by the low and medium-dose exposure, extensive and robust changes in gene expression were induced by the high-dose BPDE. We found that the expression of cell cycle-regulators, signaling molecules and transcription factors were significantly altered and important signaling pathways related to cell survival or apoptosis were affected by BPDE. Several genes and related regulatory pathways that were previously not known to be responsive to this genotoxic agent have now been implicated, which helps to draw the whole picture of how cells respond to environmental chemical exposure via transcriptional regulation. Experiment Overall Design: Human amnion epithelial FL cells were exposed to vehicle control (dimethyl sulfoxide) and increasing doses (5, 50, 500 nM) of anti-benzo(a)pyrene diol epoxide (anti-BPDE), respectively. The transcriptomes of the three treatments were compared to that of the control, respectively, to test the hypothesis that a characterized differential expression profile would be generated by exposure to various doses of this genotoxic agent.
Project description:The environmental carcinogen, (±)-anti-benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE), causes bulky-adduct DNA damages, triggers certain signaling pathways, and elicits gene expression changes. Here, we focused on the temporal gene expression changes induced by a low concentration (0.05 µM) BPDE in human amnion epithelial FL cells. Differential gene expression profiles at 1, 10 and 22 h post BPDE treatment were obtained using Affymetrix HG-U133 Plus 2.0 oligonucleotide microarrays. A cohort of gene expression changes related to cell cycle progression, cell growth or apoptosis, stress response, and post-transcriptional regulation was validated with quantitative real-time RT-PCR. The alteration of several cell cycle-related genes was correlated and possibly contributed to the cell cycle arrest phenotype. Paradoxical transcriptional regulations regarding cell growth or apoptosis emerged in response to BPDE treatment, which indicated that cell fate was determined by integrated signals. The temporal transcriptional changes would be of help to clarify the molecular mechanism of cellular response to BPDE. Experiment Overall Design: Human amnion epithelial FL cells were exposed to vehicle control (dimethyl sulfoxide) and a low concentration (0.05 µM) (±)-anti-benzo[a]pyrene-7,8-diol-9,10-epoxide, respectively. The differential gene expression profiles at 1, 10 and 22 h post BPDE treatment were obtained using Affymetrix HG-U133 Plus 2.0 oligonucleotide microarrays. The transcriptomic changes at different time points post BPDE treatment would provide insight into the dynamic processes of cellular response to this genotoxic agent.
Project description:Genotoxic agents cause cellular DNA damage and stress responses, including transcriptional changes. Here we focused on the early transcriptional responses of human cells to benzo(a)pyrene diol epoxide (BPDE), which causes bulky DNA adduct damage. Human amnion epithelial FL cells were exposed to three doses of BPDE (5, 50, and 500 nM) and the vehicle control DMSO, and differential gene expression profiles were obtained 4 h after exposure using oligonucleotide microarrays followed by validation with quantitative real-time RT-PCR. Compared with a few genes affected by the low and medium-dose exposure, extensive and robust changes in gene expression were induced by the high-dose BPDE. We found that the expression of cell cycle-regulators, signaling molecules and transcription factors were significantly altered and important signaling pathways related to cell survival or apoptosis were affected by BPDE. Several genes and related regulatory pathways that were previously not known to be responsive to this genotoxic agent have now been implicated, which helps to draw the whole picture of how cells respond to environmental chemical exposure via transcriptional regulation. Keywords: Dose response
Project description:The environmental carcinogen, (±)-anti-benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE), causes bulky-adduct DNA damages, triggers certain signaling pathways, and elicits gene expression changes. Here, we focused on the temporal gene expression changes induced by a low concentration (0.05 µM) BPDE in human amnion epithelial FL cells. Differential gene expression profiles at 1, 10 and 22 h post BPDE treatment were obtained using Affymetrix HG-U133 Plus 2.0 oligonucleotide microarrays. A cohort of gene expression changes related to cell cycle progression, cell growth or apoptosis, stress response, and post-transcriptional regulation was validated with quantitative real-time RT-PCR. The alteration of several cell cycle-related genes was correlated and possibly contributed to the cell cycle arrest phenotype. Paradoxical transcriptional regulations regarding cell growth or apoptosis emerged in response to BPDE treatment, which indicated that cell fate was determined by integrated signals. The temporal transcriptional changes would be of help to clarify the molecular mechanism of cellular response to BPDE. Keywords: time course
Project description:Cellular responses to carcinogens are typically studied in transformed cell lines, which do not reflect the physiological status of normal tissues. To address this question, we have characterized the transcriptional program and cellular responses of normal human lung WI-38 fibroblasts upon exposure to the ultimate carcinogen benzo[a]pyrene diol epoxide (BPDE). Exposure to BPDE induces a strong inflammatory response in WI-38 primary fibroblasts. Whole-genome microarray analysis shows induction of several genes related to the production of inflammatory factors, including those that encode interleukins (ILs), growth factors, and enzymes related to prostaglandin synthesis and signaling. This is the first demonstration that a strong inflammatory response is triggered in primary fibroblasts in response to a reactive diol epoxide derived from a polycyclic aromatic hydrocarbon.
Project description:Human colon carcinoma cells (HCT116) differing in p53 status were exposed to benzo(a)pyrene (BaP) (2.5 and 5 uM for up to 48 h) or anti-benzo(a)pyrene-trans-7,8-dihydrodiol-9,10-epoxide (BPDE)(0.5 and 1 uM for up to 24 h), and their gene expression responses compared by cDNA microarray technology. Keywords: BaP or BPDE exposure
Project description:Global loss of DNA methylation and locus/gene-specific gain of DNA methylation are two distinct hallmarks of carcinogenesis. Aberrant DNA methylation is implicated in smoking-related lung cancer. In this study, we have comprehensively investigated the modulation of DNA methylation consequent to chronic exposure to a prototype smoke-derived carcinogen, benzo[a]pyrene diol epoxide (B[a]PDE), in genomic regions of significance in lung cancer, in normal human cells. We have used a pulldown assay for enrichment of the CpG methylated fraction of cellular DNA combined with microarray platforms, followed by extensive validation through conventional bisulfite-based analysis. Here, we demonstrate strikingly similar patterns of DNA methylation in non-transformed B[a]PDE-treated cells vs control using high-throughput microarray-based DNA methylation profiling confirmed by conventional bisulfite-based DNA methylation analysis. The absence of aberrant DNA methylation in our model system within a timeframe that precedes cellular transformation suggests that following carcinogen exposure, other as yet unknown factors (secondary to carcinogen treatment) may help initiate global loss of DNA methylation and region-specific gain of DNA methylation, which can, in turn, contribute to lung cancer development. Unveiling the initiating events that cause aberrant DNA methylation in lung cancer has tremendous public health relevance, as it can help define future strategies for early detection and prevention of this highly lethal disease. Methylated fragments in genomic DNA extracted from benzo[a]pyrene diol epoxide (B[a]PDE)-treated normal human fibroblasts versus control (solvent [dimethylsulfoxide (DMSO)-treated counterpart cells] were enriched with the MIRA assay and hybridized together with input genomic DNA to NimbleGen's whole genome tiling array.
Project description:Benzo[a]pyrene (BaP) is a known human carcinogen (IARC Group 1) found in food, coal tar, as well as cigarettes and other smoke. Its diol-epoxide metabolites (Benzo[a]pyrene diol-epoxide [BPDE]) react with DNA forming DNA adducts, predominantly N2-BPDE-deoxyguanosine (N2-BPDE-dG). While the capacity of BPDEs to alkylate DNA and induce mutations is well known, little is known about how the genomic features influence the accumulation of DNA damage at a genome-wide level. To bridge this gap, we developed a single-nucleotide resolution damage sequencing method to map N2-BPDE-dG in a BPDE exposed human lung cell line, and combined this analysis with mass spectrometry to quantify the total absolute levels of the adduct in the genome. Comparing damage abundance with DNase hypersensitive sites, transcription levels, and other genome annotation data showed that although the overall adduct levels increased with increasing concentration of BPDE, the genomic distribution patterns of N2-BPDE-dG were stable and correlated with the genomic features related to chromatin state and transcriptional activities. In addition, we extracted the preferred local DNA sequence contexts for N2-BPDE-dG, i.e., its DNA damage signature, and found that it was highly similar to the mutational signatures identified from smoking-related lung cancers. These results suggest that genomic features and sequence contexts are important in shaping the landscape of DNA damage arising from chemical exposures and provide an effective strategy for linking single-nucleotide resolution damage sequencing data with cancer mutations.
2023-02-01 | GSE224001 | GEO
Project description:Effects on gene expression profile in human bronchial epithelial cells exposed to benzo[a]pyrene diol epoxide