IGF-II receptor number is increased in TE-85 osteosarcoma cells by combined magnetic fields

• Published in: Journal of bone and mineral research Vol. 10; no. 5; p. 812
• Main Authors: Fitzsimmons, R J, Ryaby, J T, Magee, F P, Baylink, D J
• Format: Journal Article
• Language: English
• Published: United States 01.05.1995
• Subjects: Analysis of Variance; Binding, Competitive; Bone Development - physiology; Bone Neoplasms - pathology; Bone Remodeling - physiology; Cell Division - drug effects; DNA - biosynthesis; Dose-Response Relationship, Drug; Electromagnetic Fields - adverse effects; Humans; Insulin-Like Growth Factor I - metabolism; Insulin-Like Growth Factor I - pharmacology; Insulin-Like Growth Factor II - metabolism; Insulin-Like Growth Factor II - pharmacology; Osteoblasts - cytology; Osteoblasts - physiology; Osteosarcoma - pathology; Receptor, IGF Type 2 - drug effects; Receptor, IGF Type 2 - metabolism; Receptor, IGF Type 2 - physiology; Signal Transduction; Tumor Cells, Cultured
• ISSN: 0884-0431
• DOI: 10.1002/jbmr.5650100519

Human osteosarcoma-derived osteoblast-like cells, TE-85, were used to assess the effect of a low frequency alternating magnetic field in combination with a controlled static magnetic field (combined magnetic fields, CMF) on insulin-like growth factor receptor regulation. In our culture system, application of a 15.3 Hz CMF induces a calculated maximum electrical potential in the culture media of 10(-5) V/m. Initial characterization of TE-85 cells demonstrated that (a) TE-85 cells contain both type I insulin-like growth factor (IGF-I) and IGF-II receptors and (b) dose dependence for IGF-stimulated cell proliferation were comparable to the affinities of the IGF's binding to membrane binding sites (i.e., receptors had dissociation constants in the low nanomolar concentration range). The studies with CMF exposure revealed that CMF treatment for 30 minutes increased the number of IGF-II receptors in a frequency-dependent manner without affecting the number of IGF-I receptors. The CMF-dependent increase in IGF-II receptor number was associated with a significant increase in the IGF-II dissociation constant. These results indicate that a membrane receptor levels can be altered by short-term exposure to low-energy, low-frequency electromagnetic fields and suggest a potential biochemical mechanism for electromagnetic effects on bone formation and remodeling.