Successful growth and characterization of mouse pancreatic ductal cells: functional properties of the Ki-RAS(G12V) oncogene.
OBJECTIVE
The Ki-RAS oncogene is altered in pancreatic ductal neoplasms. Pancreatic ductal cells (PDCs) were purified from cytokeratin 19 (K19)-Ki-RAS(G12V) transgenic mice and control littermates to identify properties of Ki-Ras activation in a cell-type-specific context. Because Ki-RAS mutation has prognostic significance in patients treated with radiation, we studied the influence of Ki-RAS status on radiation survival.


METHODS
Pancreatic ductal fragments from mice with Ki-RAS(G12V) mutation or wild-type (WT)-Ki-RAS were cultured. Growth curves, electron microscopy, flow cytometry, and analysis of signaling and cell-cycle proteins were established. Farnesyltransferase inhibitor (FTI) treatment with R115777 before and after irradiation was used to determine the effect of Ki-Ras farnesylation on cell survival.


RESULTS
PDCs from WT and K19-Ki-RAS(G12V) mice had features of ductal cells with formation of 3-dimensional structures on collagen without differences in morphology, growth, and cell-cycle distribution. This may result from up-regulation of p16INK4 and p27(Kip1) and lack of hyperstimulation of the mitogen-activated protein kinase pathway in Ki-RAS(G12V) PDCs. No differences in radiation survival between Ki-RAS(G12V) PDCs and WT PDCs were observed. However, Ki-RAS(G12V) PDCs expressing mutant p53(V143A) had enhanced survival compared with WT PDCs transduced with p53(V143A). R115777 treatment sensitized Ki-RAS(G12V) PDCs and Ki-RAS(G12V)/p53(V143A) PDCs, but not WT PDCs.


CONCLUSIONS
Novel characterization of murine WT PDCs and Ki-RAS(G12V) PDCs is described. Induction of cell-cycle regulators and lack of mitogen-activated protein kinase hyperstimulation likely are responsible for constraining activated Ki-RAS(G12V)-mediated proliferation. Because its activation was required for sensitization by an FTI, R115777 may be useful against pancreatic tumors expressing oncogenic Ki-Ras.
Schreiber
Franz S
FS
Department of Medicine, Abramson Cancer Center, University of Pennsylvania, Philadelphia 19104-2144, USA.
Deramaudt
Therese B
TB
Brunner
Thomas B
TB
Boretti
Michael I
MI
Gooch
Keith J
KJ
Stoffers
Doris A
DA
Bernhard
Eric J
EJ
Rustgi
Anil K
AK
D000818:Animals; D018797:Cell Cycle Proteins / Q000502:physiology / Q000528:radiation effects; D002455:Cell Division / Q000235:genetics / Q000528:radiation effects*; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000528:radiation effects; D011905:Genes, ras / Q000235:genetics / Q000528:radiation effects*; D051379:Mice; D008822:Mice, Transgenic; D023421:Models, Animal; D009154:Mutation; D010183:Pancreatic Ducts / Q000528:radiation effects*; D017368:Protein Prenylation / Q000502:physiology*; D011878:Radiotherapy / Q000009:adverse effects*
D018797:Cell Cycle Proteins