The Effects of PGE₂ on HGF, IL-6 and PGE₂ Production by Radicular Cyst- and Odontogenic Keratocyst-derived Cells

Abstract

It is reported that dental cysts contain interleukin-1 (IL-1), which stimulates protaglandin secretion by fibrous capsule-derived fibroblasts. However, the mechanism of dental cyst expansion in alveolar bone remains unclear. The aim of this study was to simulate the autocrine effects of prostaglandin E₂ (PGE₂) on a growth factor for epithelial cells (hepatocyte growth factor, HGF), a bone resorbing cytokine (interleukin-6, IL-6), and PGE₂ production by human radicular cyst- and odontogenic keratocyst-derived fibroblast-like cells (RC cells and KC cells) in vitro. The confluent RC cells and KC cells and KC cells were exposed to 0.1 μmol/l of PGE₂ in serum-free DMEM for 0, 1, 3, 6, or 24 hours. The medium was harvested after 1, 3, 6, or 24 hours of each stimulation period. ELISA kits were employed to determine the amount of HGF, IL-6 and PGE₂ in the supernatant, respectively. PGE₂ significantly stimulated IL-6 production by RC cells and KC cells, and the effective stimulation time was 1 to 3 hours. PGE₂ stimulation also induced HGF production; however, the most effective stimulation time was 24 hours. Furthermore, PGE₂ stimulated PGE₂ production itself in the RC cells and KC cells, and every stimulation period was effective. These results show that PGE₂ stimulates HGF, IL-6 and PGE₂ production by RD cells and KC cells, suggesting that autocrine PGE₂ may induce radicular cyst and odontogenic keratocyst expansion once PGE₂ is produced in the cyst fibrous capsule.