Adenovirus-mediated gene transfer of RasN17 inhibits specific CCK actions on pancreatic acinar cells

CCK stimulates pleiotrophic responses in pancreatic acinar cells; however, the intracellular signaling pathways involved are not well understood. To evaluate the role of the ras gene product in CCK actions, a strategy involving in vitro adenoviral-mediated gene delivery of a dominant-negative mutant Ras (Ras(N17)) was utilized. Isolated acini were infected with various titers of either a control adenovirus or an adenoviral construct expressing Ras(N17) for 24 h before being treated with CCK. Titer-dependent expression of Ras(N17) in the acini was confirmed by Western blotting. Infection with control adenovirus [10(6)-10(9) plaque-forming units/mg acinar protein (multiplicity of infection of similar to 1-1,000)] had no effect on CCK stimulation of acinar cell amylase release, extracellular-regulated kinase (ERK) or c-Jun kinase (JNK) kinases, or DNA synthesis. In contrast, infection with adenovirus bearing ras(N17) increased basal amylase release, inhibited CCK-mediated JNK activation, had no effect on CCK activation of ERK, and inhibited DNA synthesis. These data demonstrate important roles for Ras in specific actions of CCK on pancreatic acinar function.