Abstracts
2002 Digestive Disease Week

# 105785 Abstract ID: 105785 Inhibition of the Akt Signal Transduction Pathway Complements the Response of Pancreatic Carcinoma Cells to Sulindac
Michele T Yip-Schneider, C Max Schmidt, Indianapolis, IN

Nonsteroidal anti-inflammatory drugs (NSAIDs) may be effective treatment for pancreatic adenocarcinoma. We have previously demonstrated that NSAIDs suppress pancreatic cell growth in vitro by inhibiting cell cycle progression but have little effect on apoptosis. In fact, NSAIDs in some instances increase Akt phosphorylation suggesting activation of the phosphatidylinositol 3'-kinase (PI3K)-Akt survival (anti-apoptotic) pathway. Our aim was to determine the effects of PI3K/Akt inhibition in the presence/absence of the NSAID sulindac on pancreatic cancer growth and apoptosis in vitro. The growth effects of sulindac (250-500µM) and the PI3K inhibitor LY294002 (1-100µM) in the human pancreatic carcinoma cell line Bx-PC-3 were determined by a colorimetric proliferation assay and confirmed by cell counts. Apoptosis was measured by performing an ELISA to detect DNA fragmentation. Akt phosphorylation and p21 expression were determined by western blot analysis. Treatment with sulindac (IC50=250µM) alone or LY294002 (IC50=50µM) alone resulted in dose-dependent inhibition of BxPC-3 cell growth. Decreased Akt phosphorylation was observed following LY294002 treatment confirming inhibition of the PI3K/Akt pathway. Low dose LY294002 (10µM) when combined with sulindac augmented growth inhibitory effects (85% inhibition) in BxPC-3 cells compared with LY294002 (38% inhibition) alone. LY294002 dose dependently induced apoptosis only in the presence of sulindac in BxPC-3 cells. Interestingly, LY294002 also increased the expression of the cyclin-dependent kinase inhibitor, p21, an effect that was potentiated in the presence of sulindac. Inhibition of PI3K/Akt in pancreatic cancer cells complements the growth inhibition of sulindac by lowering the apoptotic threshold and possibly augmenting the effect of sulindac on cell cycle arrest. A combined chemotherapeutic approach with NSAIDs and PI3K/Akt inhibitors in pancreatic adenocarcinoma may result in more effective tumor kill and allow the use of lower drug doses minimizing toxicity.