title: High doses of bisphosphonates reduce osteoblast-like cell proliferation by arresting the cell cycle and inducing apoptosis.
abstract: OBJECTIVE
  The study objective was to evaluate the effect on osteoblast growth of high concentrations of three nitrogen-containing bisphosphonates (pamidronate, alendronate, and ibandronate) and one non-nitrogen-containing bisphosphonate (clodronate), using the MG-63 cell line as an osteoblast model, in order to determine the role of osteoblasts in bisphosphonate-related osteonecrosis of the jaw (BRONJ).
  
  
  METHODS
  Osteoblasts were incubated in culture medium with different doses of pamidronate, alendronate, ibandronate or clodronate. The proliferative capacity of the osteoblasts was determined by spectrophotometry (MTT-based) at 24 h of culture. Flow cytometry was used to determine the percentage of cells in each cell cycle phase (G0/G1, G2/M, and S) and to discriminate apoptotic cell death from necrotic cell death in the cell cycle at 24 h of treatment.
  
  
  RESULTS
  All the bisphosphonates assayed produced a significant and dose-dependent reduction in MG-63 proliferation at the high doses assayed (10(-4) and 5 × 10(-5) M) in comparison with controls (p <0.001). Cell cycle study revealed that all assayed bisphosphonates significantly arrested the cell cycle in phase G0/G1 at doses of 10(-4) and 5 × 10(-5) M, increasing the percentage of cells in this phase (p <0.05). Apoptosis/necrosis studies showed significant changes compared with control cells, with an increased percentage of cells in apoptosis after treatment with 10(-4) or 5 × 10(-5) M of pamidronate, alendronate, ibandronate, or clodronate (p <0.05).
  
  
  CONCLUSIONS
  High doses of nitrogen-containing or non-nitrogen-containing bisphosphonates can reduce the proliferation of MG-63 osteoblast-like cells by arresting the cell cycle and inducing apoptosis/necrosis.
authors.affiliation: Department of Stomatology, School of Dentistry, University of Granada, Spain; Biomedical Group (BIO277), Department of Nursing, Faculty of Health Sciences, University of Granada, Spain; Instituto Investigación Biosanitaria, ibs.Granada, Spain.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Manzano-Moreno
authors.affiliation: Biomedical Group (BIO277), Department of Nursing, Faculty of Health Sciences, University of Granada, Spain; Instituto Investigación Biosanitaria, ibs.Granada, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Ramos-Torrecillas
authors.affiliation: Biomedical Group (BIO277), Department of Nursing, Faculty of Health Sciences, University of Granada, Spain; Instituto Investigación Biosanitaria, ibs.Granada, Spain.
authors.forename: Elvira
authors.initials: E
authors.lastname: De Luna-Bertos
authors.affiliation: Biomedical Group (BIO277), Department of Nursing, Faculty of Health Sciences, University of Granada, Spain; Instituto Investigación Biosanitaria, ibs.Granada, Spain; Institute of Neuroscience, Parque Tecnológico Ciencias de la Salud, University of Granada, Armilla, Granada, Spain. Electronic address: crr@ugr.es.
authors.forename: Concepción
authors.initials: C
authors.lastname: Ruiz
authors.affiliation: Biomedical Group (BIO277), Department of Nursing, Faculty of Health Sciences, University of Granada, Spain; Instituto Investigación Biosanitaria, ibs.Granada, Spain.
authors.forename: Olga
authors.initials: O
authors.lastname: García-Martínez
mesh_terms: D019386:Alendronate / Q000008:administration & dosage; D017209:Apoptosis / Q000187:drug effects*; D059266:Bisphosphonate-Associated Osteonecrosis of the Jaw / Q000473:pathology; D050071:Bone Density Conservation Agents / Q000008:administration & dosage*; D002453:Cell Cycle / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004002:Clodronic Acid / Q000008:administration & dosage; D004396:Coloring Agents; D004164:Diphosphonates / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry / Q000379:methods; D016193:G1 Phase / Q000187:drug effects; D006801:Humans; D000077557:Ibandronic Acid; D009336:Necrosis; D010006:Osteoblasts / Q000187:drug effects*; D000077268:Pamidronate; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D013053:Spectrophotometry / Q000379:methods; D013778:Tetrazolium Salts; D013844:Thiazoles; D013997:Time Factors
chemical_list: D050071:Bone Density Conservation Agents; D004396:Coloring Agents; D004164:Diphosphonates; D013778:Tetrazolium Salts; D013844:Thiazoles; D004002:Clodronic Acid; C022616:thiazolyl blue; D000077268:Pamidronate; D000077557:Ibandronic Acid; D019386:Alendronate
keywords: Apoptosis; BRONJ; Bisphosphonates; Cell cycle; Osteoblast; Proliferation