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OBJECTIVE: The effect of neurotensin (NT) on in vitro-growth of human pancreatic cancer cells (MIA PaCa-2) was examined. Furthermore, the intracellular signal-transduction pathways by which neurotensin regulates growth of MIA PaCa-2 cells were determined. SUMMARY BACKGROUND DATA: NT is trophic for normal rat pancreas, but the effect of NT on growth of human pancreatic cancer is not known. METHODS: Effects of NT (10(-12) to 10(-6) mol/l) on growth of MIA PaCa-2 cells were determined by both count of cell numbers and 3H-thymidine incorporation. Action of NT on phosphatidylinositol (PI) hydrolysis, cyclic AMP production, and intracellular calcium level were determined by conventional methods. The effects of 8-bromo-cyclic AMP and prostaglandin E2 on cell growth were determined. RESULTS: Low concentrations of NT (10(-12) to 10(-9) mol/l) stimulated growth in a dose-dependent manner, but higher concentrations of NT (10(-8) to 10(-6) mol/l) did not stimulate growth of MIA PaCa-2 cells. NT (10(-12) to 10(-6) mol/l) stimulated PI hydrolysis and increased intracellular calcium levels in a dose-dependent manner. High concentrations of NT (10(-8) to 10(-6) mol/l) stimulated production of cyclic AMP in a dose-dependent manner. 8-bromo-cyclic AMP inhibited growth of MIA PaCa-2 cells; prostaglandin E2 did not affect growth of MIA PaCa-2 cells. CONCLUSIONS: NT stimulates growth of MIA PaCa-2 cells through stimulation of PI hydrolysis and mobilization of calcium. Stimulation of the cyclic AMP pathway by high concentrations of NT abolishes the growth-stimulatory effect of NT that is mediated through PI hydrolysis or calcium mobilization.
Ishizuka et al. (Sat,) studied this question.