Drugs which inhibit osteoclast function suppress tumor growth through calcium reduction in bone

Xin Li, Jinhui Liao, Serk In Park, Amy J. Koh, William D. Sadler, Kenneth J. Pienta, Thomas J. Rosol, Laurie K. McCauley

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Prostate carcinoma frequently metastasizes to bone where the microenvironment facilitates its growth. Inhibition of bone resorption is effective in reducing tumor burden and bone destruction in prostate cancer. However, whether drugs that inhibit osteoclast function inhibit tumor growth independent of inhibition of bone resorption is unclear. Calcium is released during bone resorption and the calcium sensing receptor is an important regulator of cancer cell proliferation. The goal of this investigation was to elucidate the role of calcium released during bone resorption and to determine the impact of drugs which suppress bone resorption on tumor growth in bone. To compare tumor growth in a skeletal versus non-skeletal site, equal numbers of canine prostate cancer cells expressing luciferase (ACE-1luc) were inoculated into a simple collagen matrix, neonatal mouse vertebrae (vossicles), human de-proteinized bone, or a mineralized collagen matrix. Implants were placed subcutaneously into athymic mice. Luciferase activity was used to track tumor growth weekly, and at one month tumors were dissected for histologic analysis. Luciferase activity and tumor size were greater in vossicles, de-proteinized bone and mineralized collagen matrix versus non-mineralized collagen implants. The human osteoblastic prostate carcinoma cell line C4-2b also grew better in a mineral rich environment with a greater proliferation of C4-2b cells reflected by Ki-67 staining. Zoledronic acid (ZA), a bisphosphonate, and recombinant OPG-Fc, a RANKL inhibitor, were administered to mice bearing vertebral implants (vossicles) containing ACE-1 osteoblastic prostate cancer cells. Vossicles or collagen matrices were seeded with ACE-1luc cells subcutaneously in athymic mice (2 vossicles, 2 collagen implants/mouse). Mice received ZA (5μg/mouse, twice/week), (OPG-Fc at 10mg/kg, 3 times/week) or vehicle, and luciferase activity was measured weekly. Histologic analysis of the tumors, vossicles and endogenous bones and serum biochemistry were performed. Antiresorptive administration was associated with decreased serum TRAP5b, reduced osteoclast numbers, and increased tibia and vossicle bone areas. ZA significantly decreased bone marrow calcium concentrations without affecting serum calcium. ZA and OPG-Fc significantly inhibited tumor growth in bone but not in collagen implants. In conclusion, the inhibitory effects of ZA or OPG-Fc on prostate tumor growth in bone are mediated via blocking bone resorption and calcium release from bone.

Original languageEnglish
Pages (from-to)1354-1361
Number of pages8
Issue number6
Publication statusPublished - 2011 Jun 1
Externally publishedYes

Bibliographical note

Funding Information:
The authors would like to thank Dr. Rodrigo Neiva for preparation of de-proteinized bone scaffolds and Fabiana Soki for her technical assistance. This work was supported by the National Cancer Institute award P01-CA093900 (LKM and KJP).


  • Anti-resorptive
  • Bone resorption
  • Calcium
  • Osteoprotegrin (OPG)
  • Prostate tumor
  • Zoledronic acid (ZA)

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Histology


Dive into the research topics of 'Drugs which inhibit osteoclast function suppress tumor growth through calcium reduction in bone'. Together they form a unique fingerprint.

Cite this