Synergistic chromatin repression of the tumor suppressor gene RARB in human prostate cancers.
DNA methylation and polycomb proteins are well-known mediators of epigenetic silencing in mammalian cells. Usually described as mutually exclusive, this statement is today controversial and recent in vitro studies suggest the co-existence of both repressor systems. We addressed this issue in the study of Retinoic Acid Receptor β (RARβ), a tumor suppressor gene frequently silenced in prostate cancer. We found that the RARβ promoter is hypermethylated in all studied prostate tumors and methylation levels are positively correlated with H3K27me3 enrichments. Thus, by using bisulfite conversion and pyrosequencing of immunoprecipitated H3K27me3 chromatin, we demonstrated that DNA methylation and polycomb repression co-exist in vivo at this locus. We found this repressive association in 6/6 patient tumor samples of different Gleason score, suggesting a strong interplay of DNA methylation and EZH2 to silence RARβ during prostate tumorigenesis.
CNRS-Pierre Fabre USR3388; Epigenetic Targeting of Cancer (ETaC); Toulouse, France; MNHN CNRS UMR7196; Paris, France; INSERM U565; Paris, France; Université Pierre et Marie Curie; Paris, France.
Céline
C
Moison
CNRS-Pierre Fabre USR3388; Epigenetic Targeting of Cancer (ETaC); Toulouse, France.
Fanny
F
Assemat
Laboratory for Functional Genomics; Fondation Jean Dausset - CEPH; Paris, France.
Antoine
A
Daunay
Laboratory for Functional Genomics; Fondation Jean Dausset - CEPH; Paris, France; Laboratory for Epigenetics and Environment; Centre National de Génotypage; CEA-Institut de Génomique; Evry, France.
Jörg
J
Tost
MNHN CNRS UMR7196; Paris, France; INSERM U565; Paris, France.
Anne-Laure
AL
Guieysse-Peugeot
CNRS-Pierre Fabre USR3388; Epigenetic Targeting of Cancer (ETaC); Toulouse, France.
Paola B
PB
Arimondo
D000368:Aged; D002843:Chromatin / Q000378:metabolism*; D018899:CpG Islands; D019175:DNA Methylation; D016147:Genes, Tumor Suppressor; D006657:Histones / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000378:metabolism*
D002843:Chromatin; D006657:Histones; D018168:Receptors, Retinoic Acid; C082925:retinoic acid receptor beta
DNA hypermethylation; EZH2; H3K27 trimethylation; polycomb protein; prostate cancer; retinoic acid receptor beta (RARβ)