Prostaglandins (PG) are produced throughout the gastrointestinal tract and are critical mediators for a complex array of physiologic and pathophysiologic processes in the intestine. Intestinal myofibroblasts, which express cyclooxygenase (COX) and generate PGE 2 , play important roles in intestinal epithelial proliferation, differentiation, inflammation, and neoplasia through secreting growth factors and cytokines. Here, we show that PGE 2 activated human intestinal subepithelial myofibroblasts (18Co) through Gs protein-coupled E-prostanoid receptors and the cyclic AMP/protein kinase A pathway. 18Co cells and primary colonic myofibroblast isolates expressed a number of growth factors; several of them were dramatically regulated by PGE 2 . An epidermal growth factor-like growth factor, amphiregulin (AR), which was not expressed by untreated cells, was strongly induced by PGE 2 . Expression of vascular endothelial growth factor A (VEGFA) was rapidly increased by PGE 2 exposure. Hepatocyte growth factor (HGF) was elevated in PGE 2 -treated myofibroblasts at both mRNA and protein levels. Thus, PGE 2 -activated myofibroblasts promoted the proliferation and migration of intestinal epithelial cells, which were attenuated by neutralizing antibodies to AR and HGF, respectively. Moreover, in the presence of PGE 2 , myofibroblasts strongly stimulated the migration and tubular formation of vascular endothelial cells. Neutralizing antibody to VEGFA inhibited the observed stimulation of migration. These results suggest that myofibroblast-generated growth factors are important mediators for PGE 2 -induced intestinal epithelial proliferation and angiogenesis, which play critical roles in intestinal homeostasis, inflammation, and neoplasia. (Cancer Res 2006; 66(2): 846-55)