title: Changes in polyamines, c-myc and c-fos gene expression in osteoblast-like cells exposed to pulsed electromagnetic fields.
abstract: Pulsed electromagnetic field (PEMF) stimulation promotes the healing of fractures in humans, though its effect is little known. The processes of tissue repair include protein synthesis and cell differentiation. The polyamines (PA) are compounds playing a relevant role in both protein synthesis processes and cell differentiation through c-myc and c-fos gene activation. Since several studies have demonstrated that PEMF acts on embryonic bone cells, human osteoblast-like cells and osteosarcoma TE-85 cell line, in this study we analyzed the effect on cell PAs, proliferation, and c-myc and c-fos gene expression of MG-63 human osteoblast-like cell cultures exposed to a clinically useful PEMF. The cells were grown in medium with 0.5 or 10% fetal calf serum (FCS). c-myc and c-fos gene expressions were determined by RT-PCR. Putrescine (PUT), spermidine (SPD), or spermine (SPM) levels were evaluated by HPLC. [(3)H]-thymidine was added to cultures for DNA analysis. The PEMF increased [(3)H]-thymidine incorporation (P < or = .01), while PUT decreased after treatment (P < or = .01); SPM and SPD were not significantly affected. c-myc was activated after 1 h and downregulated thereafter, while c-fos mRNA levels increased after 0.5 h and then decreased. PUT, SPD, SPM trends, and [(3)H]-thymidine incorporation were significantly related to PEMF treatment. These results indicate that exposure to PEMF exerts biological effects on the intracellular PUT of MG-63 cells and DNA synthesis, influencing the genes encoding c-myc and c-fos gene expression. These observations provide evidence that in vitro PEMF affects the mechanisms involved in cell proliferation and differentiation.
authors.affiliation: Department of Morphology and Embryology, Section of Histology and Embryology, University of Ferrara, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: De Mattei
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Gagliano
authors.forename: Claudia
authors.initials: C
authors.lastname: Moscheni
authors.forename: Claudia
authors.initials: C
authors.lastname: Dellavia
authors.forename: Carla
authors.initials: C
authors.lastname: Calastrini
authors.forename: Agnese
authors.initials: A
authors.lastname: Pellati
authors.forename: Magda
authors.initials: M
authors.lastname: Gioia
authors.forename: Angelo
authors.initials: A
authors.lastname: Caruso
authors.forename: Giordano
authors.initials: G
authors.lastname: Stabellini
mesh_terms: D002454:Cell Differentiation / Q000502:physiology / Q000528:radiation effects; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields; D005786:Gene Expression Regulation / Q000502:physiology / Q000528:radiation effects*; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects*; D010012:Osteogenesis / Q000502:physiology / Q000528:radiation effects; D011073:Polyamines / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D011829:Radiation Dosage; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D004268:DNA-Binding Proteins; C116115:MYCBP protein, human; D011073:Polyamines; D016760:Proto-Oncogene Proteins c-fos; D014157:Transcription Factors