ABSTRACT: IP of 5-methylcytosine (5-mc) enriched DNA fragments from control, PB treated mouse livers, resulting Ctnnb1 mutated PB liver tumours and PB minus Ha-Ras mutate liver tumour
Project description:This SuperSeries is composed of the following subset Series: GSE40537: IP of 5-hydroxymethylcytosine (5-hmC) enriched DNA fragments from control and PB treated mouse livers GSE40538: IP of 5-methylcytosine (5-mC) enriched DNA fragments from control and PB treated mouse livers GSE40773: Dynamic changes in liver 5M-bM-^@M-^P hydroxymethylcytosine profiles upon nonM-bM-^@M-^P genotoxic carcinogen exposure Refer to individual Series
Project description:IP of 5-hydroxymethylcytosine (5-hmC) enriched DNA fragments from control ,PB treated mouse livers , resulting Ctnnb1 mutated PB liver tumours and PB minus Ha-Ras mutate liver tumour
Project description:Through the analysis of mouse liver tumours promoted by distinct routes (DEN exposure alone, DEN exposure plus non-genotoxic insult with phenobarbital and non-alcoholic fatty liver disease); we report that the cancer associated hyper-methylated CGI events in mice are also predicated by silent promoters that are enriched for both the DNA modification 5-hydroxymethylcytosine (5hmC) and the histone modification H3K27me3 in normal liver. During cancer progression these CGIs undergo hypo-hydroxymethylation, prior to subsequent hyper-methylation; whilst retaining H3K27me3. A similar loss of promoter-core 5hmC is observed in Tet1 deficient mouse livers indicating that reduced Tet1 binding at CGIs may be responsible for the epigenetic dysregulation observed during hepatocarcinogenesis. Consistent with this reduced Tet1 protein levels are observed in mouse liver tumour lesions. As in human, DNA methylation changes at CGIs do not appear to be direct drivers of hepatocellular carcinoma progression in mice. Instead dynamic changes in H3K27me3 promoter deposition are strongly associated with tumour-specific activation and repression of transcription. Our data suggests that loss of promoter associated 5hmC in diverse liver tumours licences DNA methylation reprogramming at silent CGIs during cancer progression. 5-mc is a well establisehd epigenetic mark typically related to gene silencing events. Phenobarbital (PB) is a well studied non-genotoxic carcinogen with roles in epigenetic perturbation. We profile 5mC in both control mouse livers as well as in the livers of 12 week PB treated mice. We also profile 5mC in liver tumours arising in the presence of long term PB exposure (35 week: resulting in Ctnnb1 mutated tumours) to a Ha-Ras liver tumour which arose without PB. Samples: 2 control and 2 PB exposed mouse livers, 3 liver tumours resulting from long term PB exposrue and 1 liver tumour arising without PB
Project description:Through the analysis of mouse liver tumours promoted by distinct routes (DEN exposure alone, DEN exposure plus non-genotoxic insult with phenobarbital and non-alcoholic fatty liver disease); we report that the cancer associated hyper-methylated CGI events in mice are also predicated by silent promoters that are enriched for both the DNA modification 5-hydroxymethylcytosine (5hmC) and the histone modification H3K27me3 in normal liver. During cancer progression these CGIs undergo hypo-hydroxymethylation, prior to subsequent hyper-methylation; whilst retaining H3K27me3. A similar loss of promoter-core 5hmC is observed in Tet1 deficient mouse livers indicating that reduced Tet1 binding at CGIs may be responsible for the epigenetic dysregulation observed during hepatocarcinogenesis. Consistent with this reduced Tet1 protein levels are observed in mouse liver tumour lesions. As in human, DNA methylation changes at CGIs do not appear to be direct drivers of hepatocellular carcinoma progression in mice. Instead dynamic changes in H3K27me3 promoter deposition are strongly associated with tumour-specific activation and repression of transcription. Our data suggests that loss of promoter associated 5hmC in diverse liver tumours licences DNA methylation reprogramming at silent CGIs during cancer progression. 5-hmC is a novel epigenetic mark derived from oxidation of methylcytosine. Phenobarbital (PB) is a well studied non-genotoxic carcinogen with roles in epigenetic perturbation. We profile 5hmC in both control mouse livers as well as in the livers of 12 week PB treated mice. We also profile 5hmC in liver tumours arising in the presence of long term PB exposure (35 week: resulting in Ctnnb1 mutated tumours) to a Ha-Ras liver tumour which arose without PB. Samples: 5hmC profiles in 2 control and 2 PB exposed mouse livers, 3 liver tumours resulting from long term PB exposrue and 1 liver tumour arising without PB
Project description:Signaling through the Wnt/b-catenin pathway is a crucial determinant of hepatic zonal gene expression, liver development, regeneration, and tumorigenesis. The gene encoding b-catenin is called Ctnnb1. We have previously shown, that liver tumour promotion mediated by the model tumour promoter phenobarbital (PB) is completely lost in mice, where Ctnnb1 has been conditionally knocked out in hepatocytes (CTNNB1KO mice; Rignall et al., Carcinogenesis 32, 52-57, 2010). In the present study, the effect of a 12 weeks PB exposure on the liver miRNA expression pattern was investigated, in order to potentially get information on the nature of the loss of promotional activity in the CTNNB1KO mice.
