Filters
Technology
Platform
GSE68387
Mus musculus, Rattus norvegicus, Homo sapiens
56 Downloadable Samples
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Phenobarbital mediates an epigenetic switch at the constitutive androstane receptor (CAR) target gene Cyp2b10 in the liver of B6C3F1 mice.
Sample Metadata Fields
Sex, Age, Specimen part, Treatment, Subject, Time
View Samples- Mus musculus
- 40 Downloadable Samples
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Phenobarbital mediates an epigenetic switch at the constitutive androstane receptor (CAR) target gene Cyp2b10 in the liver of B6C3F1 mice.
Sample Metadata Fields
Sex, Specimen part, Treatment, Subject
View Samples- Mus musculus
- 40 Downloadable Samples
Description
Evidence suggests that epigenetic perturbations are involved in the adverse effects associated with some drugs and toxicants, including certain classes of non-genotoxic carcinogens. Such epigenetic changes (altered DNA methylation and covalent histone modifications) may take place at the earliest stages of carcinogenesis and their identification holds great promise for biomedical research. Here, we evaluate the sensitivity and specificity of genome-wide epigenomic and transcriptomic profiling in phenobarbital (PB)-treated B6C3F1 mice, a well-characterized rodent model of non-genotoxic liver carcinogenesis. Methylated DNA Immunoprecipitation (MeDIP)-coupled microarray profiling of 17,967 promoter regions and 4,566 intergenic CpG islands was combined with genome-wide mRNA expression profiling to identify liver tissue-specific PB-mediated DNA methylation and transcriptional alterations. Only a limited number of significant anti-correlations were observed between PB-induced transcriptional and promoter-based DNA methylation perturbations. However, the constitutive androstane receptor (CAR) target gene Cyp2b10 was found to be concomitantly hypomethylated and transcriptionally activated in a liver tissue-specific manner following PB treatment. Furthermore, analysis of active and repressive histone modifications using chromatin immunoprecipitation revealed a strong PB-mediated epigenetic switch at the Cyp2b10 promoter. Our data reveal that PB-induced transcriptional perturbations are not generally associated with broad changes in the DNA methylation status at proximal promoters and suggest that the drug-inducible CAR pathway regulates an epigenetic switch from repressive to active chromatin at the target gene Cyp2b10. This study demonstrates the utility of integrated epigenomic and transcriptomic profiling for elucidating early mechanisms and biomarkers of non-genotoxic carcinogenesis.
Publication Title
Phenobarbital mediates an epigenetic switch at the constitutive androstane receptor (CAR) target gene Cyp2b10 in the liver of B6C3F1 mice.
Sample Metadata Fields
Sex, Specimen part, Treatment, Subject
View Samples- Mus musculus
- 3 Downloadable Samples
Description
BRCA1, a well-known breast and ovarian cancer susceptibility gene with multiple interacting partners, is predicted to have diverse biological functions. However, to date its only well-established role is in the repair of damaged DNA and cell cycle regulation. In this regard, the etiopathological study of low penetrant variants of BRCA1 provides an opportunity to uncover its other physiologically important functions. Using this rationale, we studied the R1699Q variant of BRCA1, a potentially moderate risk variant, and found that it does not impair DNA damage repair but abrogates the repression of miR-155, a bona fide oncomir. We further show that in the absence of functional BRCA1, miR-155 is up-regulated in BRCA1-deficient mouse mammary epithelial cells, human and mouse BRCA1-deficienct breast tumor cell lines as well as tumors. Mechanistically, we found that BRCA1 represses miR-155 expression via its association with HDAC2, which deacetylates H2A and H3 on the miR-155 promoter. Finally, we show that over-expression of miR-155 accelerates whereas the knockdown of miR-155 attenuates the growth of tumor cell lines in vivo. Taken together, our findings demonstrate a new mode of tumor suppression by BRCA1 and reveal miR-155 as a potential therapeutic target for BRCA1-deficient tumors.
Publication Title
Tumor suppressor BRCA1 epigenetically controls oncogenic microRNA-155.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 3 Downloadable Samples
Description
We examined the functional significance of the R1699Q variant of human BRCA1 gene using a mouse ES cell-based assay.
Publication Title
Tumor suppressor BRCA1 epigenetically controls oncogenic microRNA-155.
Sample Metadata Fields
Specimen part
View Samples