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Title: Modulation of miR-29 Expression by Alpha-fetoprotein is linked to the Hepatocellular Carcinoma Epigenome      
dateReleased:
09-23-2014
description:
Globally, hepatocellular carcinoma (HCC) accounts for 70-85% of primary liver cancers and ranks second in the leading cause of male cancer death. Serum alpha-fetoprotein (AFP), normally highly expressed in the liver only during fetal development, is reactivated in 60% of HCC tumors and associated with poor patient outcome. We hypothesize that AFP+ and AFP- tumors differ biologically. Using microarray-based global microRNA profiling in 223 HCC patients, we found that members of the miR-29 family were the most significantly (p<0.001) down-regulated miRNAs in AFP+ tumors. Consistent with miR-29's role in targeting DNA methyltransferase 3A (DNMT3A), a key enzyme regulating DNA methylation, we found a significant inverse correlation (p<0.001) between miR-29 and DNMT3A gene expression suggesting that they might be functionally antagonistic. Moreover, global DNA methylation array profiling reveals that AFP+ and AFP- HCC tumors have distinct global DNA methylation patterns and that increased DNA methylation is associated with AFP+ HCC. Interestingly, miR-29 family physiological expression is low in mouse embryonic livers but gradually increases after birth. This is in contrary to AFP expression, which dramatically decreases after birth. Experimentally, we demonstrated that increased AFP expression, or conditioned media from AFP expressing HCC cells, inhibits miR-29a expression in AFP- HCC cells. AFP also inhibited transcription of the miR-29a/b-1 locus and this effect is mediated through c-MYC binding to the miR-29a/b-1 promoter. Our findings indicate that tumor biology differs considerably between AFP+ HCC and AFP- HCC and that AFP is a functional antagonist of miR-29, which may contribute to global epigenetic alterations and poor prognosis in HCC. Illumina Human BeadChip Methylation microarrays were completed on 48 tumor HCC tissues.
privacy:
not applicable
aggregation:
instance of dataset
ID:
E-GEOD-52018
refinement:
raw
alternateIdentifiers:
52018
keywords:
functional genomics
dateModified:
09-27-2014
creators:
Xin Wei Wang
availability:
available
types:
gene expression
name:
Homo sapiens
ID:
A-GEOD-8490
name:
Illumina HumanMethylation27 BeadChip (HumanMethylation27_270596_v.1.2)
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-52018/E-GEOD-52018.raw.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-52018/E-GEOD-52018.processed.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE52018
storedIn:
Gene Expression Omnibus
qualifier:
not compressed
format:
HTML
accessType:
landing page
primary:
true
authentication:
none
authorization:
none
abbreviation:
EBI
homePage: http://www.ebi.ac.uk/
ID:
SCR:004727
name:
European Bioinformatics Institute
homePage: https://www.ebi.ac.uk/arrayexpress/
ID:
SCR:002964
name:
ArrayExpress