Use of interfering RNA to investigate the role of endogenous gastrin in the survival of gastrointestinal cancer cells

Br J Cancer. 2007 Feb 12;96(3):464-73. doi: 10.1038/sj.bjc.6603588. Epub 2007 Jan 30.


Gastrin isoforms, acting through a variety of receptors, have proliferative and anti-apoptotic effects on gastrointestinal (GI) cancers. A small interfering RNA (siRNA) targeting the gastrin gene was used to investigate the role of endogenous gastrin in GI cancer cell survival. Downregulation of the gastrin gene in siRNA-transfected cells was measured using real-time reverse transcriptase-PCR. The most effective siRNA was tested in a panel of GI cancer cell lines at various concentrations and time points, and the effect on cell survival and apoptosis was measured using methyl thiazoyl tetrazolium (MTT) and caspase 3 activation assays. Gastrin siRNA reduced gene expression by more than 90% in a range of GI cancer cell lines. Downregulation of the gastrin gene was dose-dependent and effective over approximately 1 week in vitro. However, downregulation at the protein level was delayed by 3-4 days. Gastrin siRNA-transfected cells showed up to a 60% reduction in growth and up to a 50% increase in apoptosis compared with control siRNA-transfected cells. The effects were most marked in the cell line with the highest constitutive level of gastrin gene expression (human metastatic colon, C170HM2) and in epidermal growth factor (EGF)-treated cells as the gastrin promoter contains an EGF-response element, gERE. The ability of the siRNAs to reduce survival of these GI cell lines is further evidence of the importance of autocrine and/or intracrine gastrin loops in GI cancer, where expression of the gastrin gene and autonomous gastrin appears widespread.

MeSH terms

  • Apoptosis
  • Cell Line, Tumor
  • Cell Survival
  • Down-Regulation
  • Epidermal Growth Factor / pharmacology
  • Gastrins / genetics*
  • Gastrins / physiology*
  • Gastrointestinal Neoplasms / pathology*
  • Humans
  • RNA Interference*
  • RNA, Small Interfering / pharmacology


  • Gastrins
  • RNA, Small Interfering
  • Epidermal Growth Factor