Clinical & Experimental Metastasis

, Volume 25, Issue 2, pp 119–129

Inhibition of RANKL blocks skeletal tumor progression and improves survival in a mouse model of breast cancer bone metastasis

  • Jude R. Canon
  • Martine Roudier
  • Rebecca Bryant
  • Sean Morony
  • Marina Stolina
  • Paul J. Kostenuik
  • William C. Dougall
Research Paper

DOI: 10.1007/s10585-007-9127-1

Cite this article as:
Canon, J.R., Roudier, M., Bryant, R. et al. Clin Exp Metastasis (2008) 25: 119. doi:10.1007/s10585-007-9127-1

Abstract

Bone metastases cause severe skeletal morbidity including fractures and hypercalcemia. Tumor cells in bone induce activation of osteoclasts, which mediate bone resorption and release of growth factors from bone matrix, resulting in a “vicious cycle” of bone breakdown and tumor proliferation. Receptor activator of NF-κB ligand (RANKL) is an essential mediator of osteoclast formation, function, and survival, and is blocked by a soluble decoy receptor, osteoprotegerin (OPG). In human malignancies that metastasize to bone, dysregulation of the RANK/RANKL/OPG pathway can increase the RANKL:OPG ratio, a condition which favors excessive osteolysis. In a mouse model of bone metastasis, RANKL protein levels in MDA-MB-231 (MDA-231) tumor-bearing bones were significantly higher than tumor-free bones. The resulting tumor-induced osteoclastogenesis and osteolysis was dose-dependently inhibited by recombinant OPG-Fc treatment, supporting the essential role for RANKL in this process. Using bioluminescence imaging in a mouse model of metastasis, we monitored the anti-tumor efficacy of RANKL inhibition on MDA-231 human breast cancer cells in a temporal manner. Treatment with OPG-Fc in vivo inhibited growth of MDA-231 tumor cells in bony sites when given both as a preventative (dosed day 0) and as a therapeutic agent for established bone metastases (dosed day 7). One mechanism by which RANKL inhibition reduced tumor burden appears to be indirect through inhibition of the “vicious cycle” and involved an increase in tumor cell apoptosis, as measured by active caspase-3. Here, we demonstrate for the first time that OPG-Fc treatment of mice with established bone metastases resulted in an overall improvement in survival.

Keywords

RANKLOPGMDA-MB-231SurvivalBone metastasisBreast cancer

Abbreviations

BLI

Bioluminescence imaging

MDA-231Luc

Luciferase-labeled MDA-231 cells

OPG

Osteoprotegerin

OPG-Fc

Human osteoprotegerin: Fc domain fusion protein

RANK

Receptor activator of NF-κB

RANKL

Receptor activator of NF-κB ligand

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • Jude R. Canon
    • 1
  • Martine Roudier
    • 2
  • Rebecca Bryant
    • 1
  • Sean Morony
    • 3
  • Marina Stolina
    • 3
  • Paul J. Kostenuik
    • 3
  • William C. Dougall
    • 4
    • 5
  1. 1.Department of Oncology ResearchAmgen Inc.Thousand OaksUSA
  2. 2.Department of PathologyAmgen Inc.SeattleUSA
  3. 3.Department of Metabolic DisordersAmgen Inc.Thousand OaksUSA
  4. 4.Department of Oncology ResearchAmgen Inc.SeattleUSA
  5. 5.Amgen Inc.CambridgeUSA