title: DNA methyltransferase inhibition reverses epigenetically embedded phenotypes in lung cancer preferentially affecting polycomb target genes.
abstract: OBJECTIVE
  Cancer cell phenotypes are partially determined by epigenetic specifications, such as DNA methylation. Metastasis development is a late event in cancerogenesis and might be associated with epigenetic alterations.
  
  
  METHODS
  An in vivo selection approach was used to generate highly aggressive non-small cell lung cancer (NSCLC) cell lines (A549 and HTB56) followed by genome-wide DNA methylation analysis. Furthermore, the therapeutic effects of the epigenetic agent azacytidine on DNA methylation patterns and the in vivo phenotypes were explored.
  
  
  RESULTS
  Widespread changes of DNA methylation were observed during development of highly aggressive cell lines. Up to 2.5% of the CpG-rich region was differentially methylated as identified by reduced representation bisulfite sequencing compared with the less aggressive parental cell lines. DNA methyltransferase inhibition by azacytidine reversed the prometastatic phenotype; this was highly associated with the preferential loss of DNA methylation at sites that were hypermethylated during the in vivo selection. Of note, polycomb (PRC2) binding sites were particularly affected by DNA methylation changes after azacytidine exposure that persisted over time.
  
  
  CONCLUSIONS
  We could show that metastatic capability of NSCLC is closely associated with DNA methylome alterations. Because inhibition of DNA methyltransferase reversed metastasis-prone phenotype, epigenetic modulation seems to be a potential therapeutic approach to prevent metastasis formation.
authors: Authors' Affiliations: Department of Medicine A, Hematology, Hemostaseology, Oncology and Pneumology; Institute of Medical Informatics; Genetic Epidemiology of Vascular Disorders, Leibniz-Institute for Arteriosclerosis Research, University of Münster, Münster; University of Applied Science Hamm-Lippstadt, Hamm; Division of Tumor Biochemistry and Epigenetics, German Cancer Research Center, Heidelberg, Germany; and Department of Hematology and Oncology Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
authors: Antje
authors: A
authors: Hascher
authors: Ann-Kristin
authors: AK
authors: Haase
authors: Katja
authors: K
authors: Hebestreit
authors: Christian
authors: C
authors: Rohde
authors: Hans-Ulrich
authors: HU
authors: Klein
authors: Maria
authors: M
authors: Rius
authors: Dominik
authors: D
authors: Jungen
authors: Anika
authors: A
authors: Witten
authors: Monika
authors: M
authors: Stoll
authors: Isabell
authors: I
authors: Schulze
authors: Seishi
authors: S
authors: Ogawa
authors: Rainer
authors: R
authors: Wiewrodt
authors: Lara
authors: L
authors: Tickenbrock
authors: Wolfgang E
authors: WE
authors: Berdel
authors: Martin
authors: M
authors: Dugas
authors: Nils H
authors: NH
authors: Thoennissen
authors: Carsten
authors: C
authors: Müller-Tidow
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics* / Q000556:secondary; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D001374:Azacitidine / Q000494:pharmacology; D001665:Binding Sites; D045744:Cell Line, Tumor; D019175:DNA Methylation; D015257:DNA-Cytosine Methylases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009368:Neoplasm Transplantation; D010641:Phenotype; D063146:Polycomb-Group Proteins / Q000502:physiology*
chemical_list: D000964:Antimetabolites, Antineoplastic; D063146:Polycomb-Group Proteins; D015257:DNA-Cytosine Methylases; D001374:Azacitidine