5-hydroxymethylcytosine marks promoters in colon that resist DNA hypermethylation in cancer
Abstract
Background : The discovery of cytosine hydroxymethylation (5hmC) as a mechanism that potentially controls DNA methylation changes typical of neoplasia prompted us to investigate its behaviour in colon cancer. 5hmC is globally reduced in proliferating cells such as colon tumours and the gut crypt progenitors, from which tumours can arise. Results : Here, we show that colorectal tumours and cancer cells express Ten-Eleven-Translocation (TET) transcripts at levels similar to normal tissues. Genome-wide analyses show that promoters marked by 5hmC in normal tissue, and those identified as TET2 targets in colorectal cancer cells, are resistant to methylation gain in cancer. In vitro studies of TET2 in cancer cells confirm that these promoters are resistant to methylation gain independently of sustained TET2 expression. We also find that a considerable number of the methylation gain-resistant promoters marked by 5hmC in normal colon overlap with those that are marked with poised bivalent histone modifications in embryonic stem cells. Conclusions : Together our results indicate that promoters that acquire 5hmC upon normal colon differentiation are innately resistant to neoplastic hypermethylation by mechanisms that do not require high levels of 5hmC in tumours. Our study highlights the potential of cytosine modifications as biomarkers of cancerous cell proliferation.
Citation
Uribe-Lewis , S , Stark , R , Carroll , T , Dunning , M J , Bachman , M , Ito , Y , Stojic , L , Halim , S , Vowler , S L , Lynch , A G , Delatte , B , de Bony , E J , Colin , L , Defrance , M , Krueger , F , Silva , A L , ten Hoopen , R , Ibrahim , A E K , Fuks , F & Murrell , A 2015 , ' 5-hydroxymethylcytosine marks promoters in colon that resist DNA hypermethylation in cancer ' , Genome Biology , vol. 16 , 69 . https://doi.org/10.1186/s13059-015-0605-5
Publication
Genome Biology
Status
Peer reviewed
ISSN
1474-7596Type
Journal article
Description
The authors would like to acknowledge the support of The University of Cambridge, Cancer Research UK (CRUK SEB-Institute Group Award A ref10182; CRUK Senior fellowship C10112/A11388 to AEKI) and Hutchison Whampoa Limited. The Human Research Tissue Bank is supported by the NIHR Cambridge Biomedical Research Centre. FF is a ULB Professor funded by grants from the F.N.R.S. and Télévie, the IUAP P7/03 programme, the ARC (AUWB-2010-2015 ULB-No 7), the WB Health program and the Fonds Gaston Ithier. Data access: http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?token=jpwzvsowiyuamzs&acc=GSE47592Collections
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