title: Preclinical evaluation of zoledronate using an in vitro mimetic cellular model for breast cancer metastatic bone disease.
abstract: BACKGROUND
  The interactions between metastatic breast cancer cells and host cells of osteoclastic lineage in bone microenvironment are essential for osteolysis. In vitro studies to evaluate pharmacological agents are mainly limited to their direct effects on cell lines. To mimic the communication between breast cancer cells and human osteoclasts, a simple and reproducible cellular model was established to evaluate the effects of zoledronate (zoledronic acid, ZOL), a bisphosphonate which exerts antiresorptive properties.
  
  
  METHODS
  Human precursor osteoclasts were cultured on bone-like surfaces in the presence of stimuli (sRANKL, M-CSF) to ensure their activation. Furthermore, immature as well as activated osteoclasts were co-cultured with MDA-MB-231 breast cancer cells. TRAP5b and type I collagen N-terminal telopeptide (NTx) were used as markers. Osteoclasts' adhesion to bone surface and subsequent bone breakdown were evaluated by studying the expression of cell surface receptors and certain functional matrix macromolecules in the presence of ZOL.
  
  
  RESULTS
  ZOL significantly suppresses the precursor osteoclast maturation, even when the activation stimuli (sRANKL and M-SCF) are present. Moreover, it significantly decreases bone osteolysis and activity of MMPs as well as precursor osteoclast maturation by breast cancer cells. Additionally, ZOL inhibits the osteolytic activity of mature osteoclasts and the expression of integrin β3, matrix metalloproteinases and cathepsin K, all implicated in adhesion and bone resorption.
  
  
  CONCLUSIONS
  ZOL exhibits a beneficial inhibitory effect by restricting activation of osteoclasts, bone particle decomposition and the MMP-related breast cancer osteolysis.
  
  
  CONCLUSIONS
  The proposed cellular model can be reliably used for enhancing preclinical evaluation of pharmacological agents in metastatic bone disease.
authors: Laboratory of Biochemistry, Department of Chemistry, University of Patras, Patras, Greece.
authors: P G
authors: PG
authors: Dedes
authors: I
authors: I
authors: Kanakis
authors: Ch
authors: Ch
authors: Gialeli
authors: A D
authors: AD
authors: Theocharis
authors: T
authors: T
authors: Tsegenidis
authors: D
authors: D
authors: Kletsas
authors: G N
authors: GN
authors: Tzanakakis
authors: N K
authors: NK
authors: Karamanos
mesh_terms: D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000556:secondary*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D056657:Cathepsin K / Q000378:metabolism; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D024042:Collagen Type I / Q000378:metabolism; D004164:Diphosphonates / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D005260:Female; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D039661:Integrin beta3 / Q000378:metabolism; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008954:Models, Biological; D009362:Neoplasm Metastasis; D010010:Osteoclasts / Q000378:metabolism / Q000473:pathology; D010014:Osteolysis / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D053245:RANK Ligand / Q000494:pharmacology; D000077211:Zoledronic Acid
chemical_list: D050071:Bone Density Conservation Agents; D024042:Collagen Type I; D004164:Diphosphonates; D007093:Imidazoles; D039661:Integrin beta3; D053245:RANK Ligand; C505688:TNFSF11 protein, human; D000077211:Zoledronic Acid; D016173:Macrophage Colony-Stimulating Factor; C534130:CTSK protein, human; D056657:Cathepsin K