title: Down-regulation of DNMT3b in PC3 cells effects locus-specific DNA methylation, and represses cellular growth and migration.
abstract: BACKGROUND
  Aberrations in DNA methylation patterns promote changes in gene expression patterns and are invariably associated with neoplasia. DNA methylation is carried out and maintained by several DNA methyltransferases (DNMTs) among which DNMT1 functions as a maintenance methylase while DNMT3a and 3b serve as de novo enzymes. Although DNMT3b has been shown to preferentially target the methylation of DNA sequences residing in pericentric heterochromatin whether it is involved in gene specific methylation remains an open question. To address this issue, we have silenced the expression of DNMT3b in the prostate-derived PC3 cells through RNA interference and subsequently studied the accompanied cellular changes as well as the expression profiles of selected genes.
  
  
  RESULTS
  Our results demonstrate that DNMT3b depletion results in increased apoptosis and reduced migration of PC3 cells compared to the untransfected control cells. Reduced DNMT3b expression resulted in hypomethylation of retinoblastoma (Rb), retinoic-acid receptor beta (RAR-beta), and adenomatous polyposis coli (APC) gene promoters, and also culminated in increased expression of CDKN3 and cytochrome b5. Although DNMT3b silenced cells were found to have reduced growth and migratory potential, there was no apparent changes in their invasive ability compared to the parental PC3 cell line.
  
  
  CONCLUSIONS
  Our findings reveal that DNMT3b preferentially targets certain gene promoters in PC3 cells and that its depletion significantly reduces growth and migration of PC3 cells.
authors.affiliation: Department of Biological & Biomedical Sciences, The Aga Khan University, Stadium Road, Karachi 74800, Pakistan. ahmed.yaqin@aku.edu
authors.forename: Ahmed
authors.initials: A
authors.lastname: Yaqinuddin
authors.forename: Sohail A
authors.initials: SA
authors.lastname: Qureshi
authors.forename: Romena
authors.initials: R
authors.lastname: Qazi
authors.forename: Farhat
authors.initials: F
authors.lastname: Abbas
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