title: Identification of pancreatic cancer invasion-related proteins by proteomic analysis.
abstract: BACKGROUND
  Markers of pancreatic cancer invasion were investigated in two clonal populations of the cell line, MiaPaCa-2, Clone #3 (high invasion) and Clone #8 (low invasion) using proteomic profiling of an in vitro model of pancreatic cancer.
  
  
  METHODS
  Using 2D-DIGE followed by MALDI-TOF MS, two clonal sub-populations of the pancreatic cancer cell line, MiaPaCa-2 with high and low invasive capacities were incubated on matrigel 24 hours prior to analysis to stimulate cell-ECM contact and mimic in vivo interaction with the basement membrane.
  
  
  RESULTS
  Sixty proteins were identified as being differentially expressed (> 1.2 fold change and p < or = 0.05) between Clone #3 and Clone #8. Proteins found to have higher abundance levels in the highly invasive Clone #3 compared to the low invasive Clone #8 include members of the chaperone activity proteins and cytoskeleton constituents whereas metabolism-associated and catalytic proteins had lower abundance levels. Differential protein expression levels of ALDH1A1, VIM, STIP1 and KRT18 and GAPDH were confirmed by immunoblot. Using RNAi technology, STIP1 knockdown significantly reduced invasion and proliferation of the highly invasive Clone #3. Knockdown of another target, VIM by siRNA in Clone #3 cells also resulted in decreased invasion abilities of Clone #3. Elevated expression of STIP1 was observed in pancreatic tumour tissue compared to normal pancreas, whereas ALDH1A1 stained at lower levels in pancreatic tumours, as detected by immunohistochemistry.
  
  
  CONCLUSIONS
  Identification of targets which play a role in the highly invasive phenotype of pancreatic cancer may help to understand the biological behaviour, the rapid progression of this cancer and may be of importance in the development of new therapeutic strategies for pancreatic cancer.
authors.affiliation: National Institute for Cellular Biotechnology, Dublin City University, Glasnevin, Ireland, UK. naomi.walsh@dcu.ie
authors.forename: Naomi
authors.initials: N
authors.lastname: Walsh
authors.forename: Norma
authors.initials: N
authors.lastname: O'Donovan
authors.forename: Susan
authors.initials: S
authors.lastname: Kennedy
authors.forename: Michael
authors.initials: M
authors.lastname: Henry
authors.forename: Paula
authors.initials: P
authors.lastname: Meleady
authors.forename: Martin
authors.initials: M
authors.lastname: Clynes
authors.forename: Paul
authors.initials: P
authors.lastname: Dowling