title: Alendronate regulates cell invasion and MMP-2 secretion in human osteosarcoma cell lines.
abstract: BACKGROUND
  Osteosarcoma is the most common malignant bone tumor of childhood. Significant proportions of these patients eventually develop pulmonary metastases and succumb to their disease even after conventional multi-agent chemotherapy and surgical excision. Matrix metalloproteinase (MMP)-2 induced degradation of blood vessel basement membranes is an important pre-requisite for tumor invasion and metastasis. Bisphosphonates (BPs) have been known to inhibit tumor growth and metastasis in some tumors such as breast cancer, renal cell carcinoma, and prostate cancer, and may do so through inhibition of MMP secretion. We, therefore, tested the effect of BPs on tumor cell invasion, MMP-2 secretion, and apoptosis of osteosarcoma cell lines.
  
  
  METHODS
  Two osteosarcoma cell lines (SaOS-2, U(2)OS) were treated with alendronate (50, 100, and 150 microM) for 24 and 48 hr. Matrigel invasion assay was used to investigate the invasive potential of osteosarcoma cell lines before and after alendronate treatment. Real-time quantitative RT-PCR was used to determine the mRNA level of MMP-2 with and without alendronate treatment. Enzyme-linked immunosorbent assay (ELISA) was used to quantify the cytokine level of MMP-2 secreted in the condition medium. BP-induced cell apoptosis was evaluated by fluorescent flow cytometric analysis.
  
  
  CONCLUSIONS
  The results showed that alendronate inhibited cell invasion of both osteosarcoma cell lines in a dose-dependent manner. Alendronate reduced the mRNA level and cellular level of MMP-2 in both cell lines in a time and dose-dependent manner. Alendronate also induced significant apoptosis in both cell lines. Our finding suggests that alendronate downregulates MMP-2 secretion and induces apoptosis in osteosarcoma cells, which may both contribute to the reduction of invasive potential of the tumor cells.
authors.affiliation: Department of Orthopaedics and Traumatology, Chinese University of Hong Kong, Hong Kong.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Cheng
authors.forename: L
authors.initials: L
authors.lastname: Huang
authors.forename: K M
authors.initials: KM
authors.lastname: Lee
authors.forename: K
authors.initials: K
authors.lastname: Li
authors.forename: S M
authors.initials: SM
authors.lastname: Kumta
mesh_terms: D019386:Alendronate / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D018929:Cell Culture Techniques / Q000379:methods; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D016326:Extracellular Matrix Proteins; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D009361:Neoplasm Invasiveness / Q000517:prevention & control*; D012516:Osteosarcoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D012313:RNA / Q000032:analysis
chemical_list: D016326:Extracellular Matrix Proteins; D012313:RNA; D020778:Matrix Metalloproteinase 2; D019386:Alendronate