title: Pleiotropic effects of bisphosphonates on osteosarcoma.
abstract: Osteosarcoma is the most common primary malignant tumor of bone and accounts for half of all primary skeletal malignancies in children and teenagers. The prognosis for patients who fail or progress on first-line chemotherapy protocols is poor, therefore, additional adjuvant therapeutic strategies are needed. A recent feasibility study has demonstrated that the nitrogen-containing bisphosphonate zoledronic acid (ZOL) can be combined safely with conventional chemotherapy. However, the pharmacodynamics of bisphosphonate therapy is not well characterized. Osteosarcoma is a highly angiogenic tumor. Recent reports of the anti-angiogenic effects of bisphosphonates prompted us to determine whether nitrogen-containing bisphosphonate (ZOL and alendronate) treatment attenuates osteosarcoma growth by inhibition of osteoclast activity, tumor-mediated angiogenesis, or direct inhibitory effects on osteosarcoma. Here, we demonstrate that bisphosphonates directly inhibit VEGFR2 expression in endothelial cells, as well as endothelial cell proliferation and migration. Additionally, bisphosphonates also decrease VEGF-A expression in osteosarcoma (K7M3) cells, resulting in reduced stimulation of endothelial cell migration in co-culture assays. ZOL also decreases VEGFR1 expression in aggressive osteosarcoma cell lines (K7M3, 143B) and induces apoptosis of these cells, but has negligible effects on less aggressive osteosarcoma cell lines (K12 and TE85). In vivo ZOL treatment results in significant reduction in osteosarcoma-initiated angiogenesis and tumor growth in a murine model of osteosarcoma. In conclusion, bisphosphonates have diverse growth inhibitory effects on osteosarcoma through: (1) activation of apoptosis and inhibition of cell proliferation, (2) inhibition of VEGF-A and VEGFR1 expression by tumor cells, (3) inhibition of tumor-induced angiogenesis, and (4) direct inhibitory actions on endothelial cells.
authors.affiliation: Vanderbilt University Medical Center, Department of Orthopaedics, 2200 Children's Way, Nashville, TN 37232-9565, USA; Department of Orthopaedic Surgery, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Ohba
authors.affiliation: Vanderbilt University Medical Center, Department of Pathology, Microbiology and Immunology, 2200 Children's Way, Nashville, TN 37232-9565, USA.
authors.forename: Justin M M
authors.initials: JM
authors.lastname: Cates
authors.affiliation: Vanderbilt University Medical Center, Department of Orthopaedics, 2200 Children's Way, Nashville, TN 37232-9565, USA.
authors.forename: Heather A
authors.initials: HA
authors.lastname: Cole
authors.affiliation: Vanderbilt University Medical Center, Department of Cardio-Oncology, 2200 Children's Way, Nashville, TN 37232-9565, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Slosky
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Haro
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Ichikawa
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ando
authors.affiliation: Vanderbilt University Medical Center, Department of Orthopaedics, 2200 Children's Way, Nashville, TN 37232-9565, USA.
authors.forename: Herbert S
authors.initials: HS
authors.lastname: Schwartz
authors.affiliation: Vanderbilt University Medical Center, Department of Orthopaedics, 2200 Children's Way, Nashville, TN 37232-9565, USA; Vanderbilt University Medical Center, Department of Center for Bone Biology, 2200 Children's Way, Nashville, TN 37232-9565, USA; Vanderbilt University Medical Center, Department of Pathology, Microbiology and Immunology, 2200 Children's Way, Nashville, TN 37232-9565, USA; Vanderbilt University Medical Center, Department of Pharmacology, 2200 Children's Way, Nashville, TN 37232-9565, USA; Vanderbilt University Medical Center, Department of Pediatrics, 2200 Children's Way, Nashville, TN 37232-9565, USA. Electronic address: jon.schoenecker@vanderbilt.edu.
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Schoenecker
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004164:Diphosphonates / Q000627:therapeutic use*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D012516:Osteosarcoma / Q000188:drug therapy* / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D004164:Diphosphonates; D042461:Vascular Endothelial Growth Factor A
keywords: Angiogenesis; Bisphosphonate; Endothelial cell; Osteosarcoma; VEGF-A; VEGFR