Title:HSP70 Inhibitors Reduce The Osteoblast Migration By Epidermal Growth Factor
VOLUME: 18 ISSUE: 7
Author(s):Tetsu Kawabata, Takanobu Otsuka, Kazuhiko Fujita, Go Sakai, Woo Kim, Rie Matsushima-Nishiwaki, Gen Kuroyanagi, Osamu Kozawa* and Haruhiko Tokuda
Affiliation:Department of Pharmacology, Gifu University Graduate School of Medicine, Gifu, Department of Orthopedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Department of Pharmacology, Gifu University Graduate School of Medicine, Gifu, Department of Pharmacology, Gifu University Graduate School of Medicine, Gifu, Department of Pharmacology, Gifu University Graduate School of Medicine, Gifu, Department of Pharmacology, Gifu University Graduate School of Medicine, Gifu, Department of Pharmacology, Gifu University Graduate School of Medicine, Gifu, Department of Pharmacology, Gifu University Graduate School of Medicine, Gifu, Department of Pharmacology, Gifu University Graduate School of Medicine, Gifu
Keywords:HSP70, EGF, migration, p44/p42 MAP kinase, Akt, osteoblast.
Abstract:Background: We have recently reported that epidermal growth factor (EGF)
induces migration of osteoblast-like MC3T3-E1 cells through the activation of p44/p42
mitogen-activated protein (MAP) kinase, p38 MAP kinase, stress-activated protein
kinase/ c-Jun N-terminal kinase (SAPK/JNK) and Akt. Furthermore, we demonstrated
that heat shock protein 70 (HSP70) down-regulates the transforming growth factor-β-
stimulated vascular endothelial growth factor synthesis via suppression of p38 MAP
kinase in osteoblast-like MC3T3-E1 cells. However, the exact role of HSP70 underlying
osteoblast migration is not fully elucidated.
Objective: The aim of this study is to investigate the effects of HSP70 inhibitors on the
EGF-stimulated osteoblast migration, and the underlying mechanism.
Methods: Osteoblast-like MC3T3-E1 cells were treated with two types of HSP70
inhibitors, VER-155008 or YM-08. Transwell cell migration assay and wound-healing
assay were analyzed for osteoblast migration. The expression levels of HSP70 and the
phosphorylation of p38 MAP kinase, p44/p42 MAP kinase, SAPK/JNK or Akt were
evaluated by a Western blot analysis.
Results: EGF hardly affected the expression levels of HSP70 at the present or absent
of VER-155008. EGF-stimulated migration was significantly reduced by both HSP70
inhibitors, VER-155008 and YM-08, determined by a transwell cell migration assay. The
suppressive effects of both HSP70 inhibitors on the migration stimulated by EGF were
also observed by a wound-healing assay. VER-155008 inhibited the EGF-induced
phosphorylation of p44/p42 MAP kinase and AKT, but not p38 MAP kinase or
SAPK/JNK.
Conclusion: This study provides new evidence that HSP70 inhibitors reduce the EGFstimulated
migration of osteoblasts through the suppression of p44/p42 MAP kinase and
Akt.
