title: Epigenetic drug combination induces genome-wide demethylation and altered gene expression in neuro-ectodermal tumor-derived cell lines.
abstract: BACKGROUND
  Epigenetic alterations are inherent to cancer cells, and epigenetic drugs are currently primarily used to treat hematological malignancies. Pediatric neuro-ectodermal tumors originate from neural crest cells and also exhibit epigenetic alterations involving e.g. apoptotic pathways, which suggests that these tumors may also be sensitive to epigenetic drugs. This notion prompted us to assess molecular and functional effects of low dosage epigenetic drugs in neuro-ectodermal tumor-derived cell lines of pediatric origin.
  
  
  RESULTS
  In 17 neuroblastoma (NBL) and 5 peripheral primitive neuro-ectodermal tumor (PNET) cell lines a combination treatment of 5-aza-2'-deoxycytidine (DAC) and Trichostatin A (TSA) at nanomolar dosages was found to reduce proliferation and to induce wide-spread DNA demethylation, accompanied by major changes in gene expression profiles. Approximately half of the genes that were significantly up-regulated upon treatment exhibited a significant demethylation in their promoter regions. In the NBL cell lines, almost every cellular pathway (193/200) investigated showed expression alterations after treatment, especially a marked up-regulation of genes in the p53 pathway. The combination treatment also resulted in up-regulation of known epigenetically regulated genes such as X-chromosomal genes, tissue-specific genes and a limited number of imprinted genes, as well as known tumor suppressor genes and oncogenes.
  
  
  CONCLUSIONS
  Nanomolar dosages of epigenetic drugs have a dramatic impact on the genomes of neuro-ectodermal tumor-derived cell lines, including alterations in DNA methylation and concomitant alterations in gene expression.
authors.affiliation: Department of Pediatric Oncology-Hematology, Erasmus MC-Sophia Children's Hospital, Dr. Molewaterplein 60, 3015, GJ, Rotterdam, The Netherlands.
authors.forename: Floor A M
authors.initials: FA
authors.lastname: Duijkers
authors.forename: Renee X
authors.initials: RX
authors.lastname: de Menezes
authors.forename: Inès J
authors.initials: IJ
authors.lastname: Goossens-Beumer
authors.forename: Dominique J P M
authors.initials: DJ
authors.lastname: Stumpel
authors.forename: Pieter
authors.initials: P
authors.lastname: Admiraal
authors.forename: Rob
authors.initials: R
authors.lastname: Pieters
authors.forename: Jules P P
authors.initials: JP
authors.lastname: Meijerink
authors.forename: Max M
authors.initials: MM
authors.lastname: van Noesel
mesh_terms: D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D015153:Blotting, Western; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D019175:DNA Methylation / Q000235:genetics*; D044127:Epigenesis, Genetic / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics / Q000502:physiology; D006801:Humans; D017599:Neuroectodermal Tumors / Q000235:genetics*; D016133:Polymerase Chain Reaction