title: Deregulation of histone lysine methyltransferases contributes to oncogenic transformation of human bronchoepithelial cells.
abstract: BACKGROUND
  Alterations in the processing of the genetic information in carcinogenesis result from stable genetic mutations or epigenetic modifications. It is becoming clear that nucleosomal histones are central to proper gene expression and that aberrant DNA methylation of genes and histone methylation plays important roles in tumor progression. To date, several histone lysine methyltransferases (HKMTs) have been identified and histone lysine methylation is now considered to be a critical regulator of transcription. However, still relatively little is known about the role of HKMTs in tumorigenesis.
  
  
  RESULTS
  We observed differential HKMT expression in a lung cancer model in which normal human bronchial epithelial (NHBE) cells expressing telomerase, SV40 large T antigen, and Ras were immortal, formed colonies in soft agar, and expressed specific HKMTs for H3 lysine 9 and 27 residues but not for H3 lysine 4 residue. Modifications in the H3 tails affect the binding of proteins to the histone tails and regulate protein function and the position of lysine methylation marks a gene to be either activated or repressed. In the present study, suppression by siRNA of HKMTs (EZH2, G9A, SETDB1 and SUV39H1) that are over-expressed in immortalized and transformed cells lead to reduced cell proliferation and much less anchorage-independent colony growth. We also found that the suppression of H3-K9, G9A and SUV39H1 induced apoptosis and the suppression of H3-K27, EZH2 caused G1 arrest.
  
  
  CONCLUSIONS
  Our results indicate the potential of these HKMTs in addition to the other targets for epigenetics such as DNMTs and HDACs to be interesting therapeutic targets.
authors.affiliation: Department of Pulmonary Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. Hideo_Watanabe@dfci.harvard.edu
authors.forename: Hideo
authors.initials: H
authors.lastname: Watanabe
authors.forename: Kenzo
authors.initials: K
authors.lastname: Soejima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yasuda
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawada
authors.forename: Ichiro
authors.initials: I
authors.lastname: Nakachi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yoda
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Naoki
authors.forename: Akitoshi
authors.initials: A
authors.lastname: Ishizaka