title: Differential effect of FGF and PDGF on cell proliferation and migration in osteoblastic cells.
abstract: It has been known that growth factors such as fibroblast growth factor (FGF) and platelet-derived growth factor (PDGF) can promote proliferation and migration in a variety of cell types including osteoblastic cells. However, the mechanism underlying their action has not been clearly defined. The present study was undertaken to examine the effect of FGF and PDGF on cell proliferation and migration and to determine the role of extracellular signal-regulated kinase (ERK) and Akt in action of FGF and PDGF in osteoblastic cells. FGF enhanced proliferation in a dose- and time-dependent manner, whereas it did not affect cell migration. FGF induced a transient activation of ERK, but not Akt, which was inhibited by an inhibitor of MEK, the upstream kinase of ERK, but not by inhibitors of PI3K/Akt (LY294002), epidermal growth factor receptor (EGFR, AG1478), and Src (PP2). FGF-induced proliferation was inhibited by inhibitors of MEK/ERK and Src pathways. Exposure of cells to FGF stimulated transition of cell cycle from the G1 phase to S phase and increased phosphorylation of Rb. FGF-induced phosphorylation of Rb was attenuated by inhibitors of MEK/ERK and Src pathways. Cell migration studies indicated that PDGF stimulated migration, but it had no effect on cell proliferation. PDGF induced activation of ERK and Akt. The ERK activatin was inhibited by the Src inhibitor and the Akt activation was inhibited by inhibitors of EGFR and Src. PDGF-induced migration was inhibited by inhibitors of MEK/ERK, PI3K/Akt, EGFR and Src pathways. Taken together, these findings suggest that the MEK/ERK and Src pathways play an important role in the FGF-induced proliferation and signaling pathways involving MEK/ERK, EGFR, Src and PI3K/Akt mediate the PDGF-induced migration. These data are of importance in understanding the roles of these growth factors in osteoblastic cell proliferation and migration.
authors.affiliation: Department of Pediatrics, College of Medicine, Pusan National University, Pusan 602-739, South Korea. kim430@pusan.ac.kr
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Kim
authors.forename: Su Yung
authors.initials: SY
authors.lastname: Kim
authors.forename: Chae Hwa
authors.initials: CH
authors.lastname: Kwon
authors.forename: Yong Keun
authors.initials: YK
authors.lastname: Kim
mesh_terms: D000818:Animals; D002453:Cell Cycle; D002460:Cell Line; D002465:Cell Movement; D049109:Cell Proliferation; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000502:physiology*; D006801:Humans; D051379:Mice; D008954:Models, Biological; D010006:Osteoblasts / Q000378:metabolism*; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism / Q000502:physiology*; D016160:Retinoblastoma Protein / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014945:Wound Healing; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D010982:Platelet-Derived Growth Factor; D016160:Retinoblastoma Protein; D005346:Fibroblast Growth Factors; D019061:src-Family Kinases; D048049:Extracellular Signal-Regulated MAP Kinases