title: SW-620 cells treated with topoisomerase I inhibitor SN-38: gene expression profiling.
abstract: BACKGROUND
  The goal of this study was to evaluate changes in gene expression in SW-620 cells in response to SN-38 in order to further elucidate the mechanisms by which SN-38 causes apoptosis and cell cycle arrest.
  
  
  METHODS
  We used a quantitative gene expression microarray assay to identify the genes regulated by SN-38 treatment in colon cancer cells and confirmed our results with RT-PCR. By gene expression profiling, we first screened a proprietary list of about 22,000 genes.
  
  
  RESULTS
  Treatment with SN-38 cells resulted in two-fold or greater alteration in the level of expression of 192 genes compared to control treatment. Most of the affected genes were not known to be responsive to SN-38 prior to this study. SN-38 treatment of these cells was found to affect the expression of various genes involved in DNA replication, transcription, signal transduction, growth factors, cell cycle regulation, and apoptosis, as well as other genes with unknown function. Changes in expression of 14 genes were confirmed by quantitative real-time polymerase chain reaction (RT-PCR).
  
  
  CONCLUSIONS
  This study leads to an increased understanding of the biochemical pathways involved in SN-38-induced apoptosis and possibly to the identification of new therapeutic targets.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA. vinniesouza@hotmail.com
authors.forename: Vinicius
authors.initials: V
authors.lastname: Souza
authors.forename: Yan Bin
authors.initials: YB
authors.lastname: Dong
authors.forename: H Sam
authors.initials: HS
authors.lastname: Zhou
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Zacharias
authors.forename: Kelly M
authors.initials: KM
authors.lastname: McMasters