title: Epigenetic processes play a major role in B-cell-specific gene silencing in classical Hodgkin lymphoma.
abstract: Many B-lineage-specific genes are down-regulated in Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL). We investigated the involvement of epigenetic modifications in gene silencing in cHL cell lines and in microdissected primary HRS cells. We assessed the expression and methylation status of CD19, CD20, CD79B, SYK, PU.1, BOB.1/OBF.1, BCMA, and LCK, all of which are typically down-regulated in cHL. We could reactivate gene expression in cHL cell lines with the DNA demethylating agent 5-aza-deoxycytidine (5-aza-dC). Using methylation-specific polymerase chain reaction (MSP), bisulfite genomic sequencing, and digestion with methylation-sensitive endonuclease followed by polymerase chain reaction (PCR), we determined the methylation status of promoter regions of PU.1, BOB.1/OBF.1, CD19, SYK, and CD79B. Down-regulation of transcription typically correlated with hypermethylation. Using bisulfite genomic sequencing we found that in microdissected HRS cells of primary cHL SYK, BOB.1/OBF.1, and CD79B promoters were also hypermethylated. Ectopic expression of both Oct2 and PU.1 in a cHL cell line potentiated endogenous PU.1 and SYK expression after 5-aza-dC treatment. These observations indicate that silencing of the B-cell-specific genes in cHL may be the consequence of a compromised regulatory network where down-regulation of a few master transcription factors results in silencing of numerous genes.
authors.affiliation: Department of Physiological Chemistry, University of Ulm, D-89069 Ulm, Germany.
authors.forename: Alexey
authors.initials: A
authors.lastname: Ushmorov
authors.forename: Frank
authors.initials: F
authors.lastname: Leithäuser
authors.forename: Olena
authors.initials: O
authors.lastname: Sakk
authors.forename: Andreas
authors.initials: A
authors.lastname: Weinhaüsel
authors.forename: Sergey W
authors.initials: SW
authors.lastname: Popov
authors.forename: Peter
authors.initials: P
authors.lastname: Möller
authors.forename: Thomas
authors.initials: T
authors.lastname: Wirth
mesh_terms: D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D001402:B-Lymphocytes / Q000473:pathology*; D045744:Cell Line, Tumor; D019175:DNA Methylation; D000077209:Decitabine; D015536:Down-Regulation; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006689:Hodgkin Disease / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D011401:Promoter Regions, Genetic; D016539:Reed-Sternberg Cells; D014157:Transcription Factors / Q000235:genetics
chemical_list: D014157:Transcription Factors; D000077209:Decitabine; D001374:Azacitidine