title: Control of epigenetic states by WT1 via regulation of de novo DNA methyltransferase 3A.
abstract: Although tumour suppressor gene hypermethylation is a universal feature of cancer cells, little is known about the necessary molecular triggers. Here, we show that Wilms' tumour 1 (WT1), a developmental master regulator that can also act as a tumour suppressor or oncoprotein, transcriptionally regulates the de novo DNA methyltransferase 3A (DNMT3A) and that cellular WT1 levels can influence DNA methylation of gene promoters genome-wide. Specifically, we demonstrate that depletion of WT1 by short-interfering RNAs leads to reduced DNMT3A in Wilms' tumour cells and human embryonal kidney-derived cell lines. Chromatin immunoprecipitation assays demonstrate WT1 recruitment to the DNMT3A promoter region and reporter assays confirm that WT1 directly transactivates DNMT3A expression. Consistent with this regulatory role, immunohistochemical analysis shows co-expression of WT1 and DNMT3A proteins in nuclei of blastemal cells in human fetal kidney and Wilms' tumours. Using genome-wide promoter methylation arrays, we show that human embryonal kidney cells over-expressing WT1 acquire DNA methylation changes at specific gene promoters where DNMT3A recruitment is increased, with hypermethylation being associated with silencing of gene expression. Elevated DNMT3A is also demonstrated at hypermethylated genes in Wilms' tumour cells, including a region of long-range epigenetic silencing. Finally, we show that depletion of WT1 in Wilms' tumour cells can lead to reactivation of gene expression from methylated promoters, such as TGFB2, a key modulator of epithelial-mesenchymal transitions. Collectively, our work defines a new regulatory modality for WT1 involving elicitation of epigenetic alterations which is most likely crucial to its functions in development and disease.
authors.affiliation: Cancer Epigenetics Laboratory, Cellular and Molecular Medicine, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK.
authors.forename: Marianna
authors.initials: M
authors.lastname: Szemes
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Dallosso
authors.forename: Zsombor
authors.initials: Z
authors.lastname: Melegh
authors.forename: Thomas
authors.initials: T
authors.lastname: Curry
authors.forename: Yifan
authors.initials: Y
authors.lastname: Li
authors.forename: Caroline
authors.initials: C
authors.lastname: Rivers
authors.forename: James
authors.initials: J
authors.lastname: Uney
authors.forename: Ann-Sophie
authors.initials: AS
authors.lastname: Mägdefrau
authors.forename: Karolin
authors.initials: K
authors.lastname: Schwiderski
authors.forename: Ji H
authors.initials: JH
authors.lastname: Park
authors.forename: Keith W
authors.initials: KW
authors.lastname: Brown
authors.forename: Jayasha
authors.initials: J
authors.lastname: Shandilya
authors.forename: Stefan G E
authors.initials: SG
authors.lastname: Roberts
authors.forename: Karim
authors.initials: K
authors.lastname: Malik
mesh_terms: D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics / Q000378:metabolism*; D000090205:DNA Methyltransferase 3A; D044127:Epigenesis, Genetic; D015971:Gene Expression Regulation, Enzymologic; D020868:Gene Silencing; D006801:Humans; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic; D025721:WT1 Proteins / Q000502:physiology*; D009396:Wilms Tumor / Q000235:genetics
chemical_list: C000717967:DNMT3A protein, human; D025721:WT1 Proteins; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A