The bisphosphonate zoledronic acid decreases tumor growth in bone in mice with defective osteoclasts.
Bisphosphonates (BPs), bone targeted drugs that disrupt osteoclast function, are routinely used to treat complications of bone metastasis. Studies in preclinical models of cancer have shown that BPs reduce skeletal tumor burden and increase survival. Similarly, we observed in the present study that administration of the Nitrogen-containing BP (N-BP), zoledronic acid (ZA) to osteolytic tumor-bearing Tax+ mice beginning at 6 months of age led to resolution of radiographic skeletal lesions. N-BPs inhibit farnesyl diphosphate (FPP) synthase, thereby inhibiting protein prenylation and causing cellular toxicity. We found that ZA decreased Tax+ tumor and B16 melanoma viability and caused the accumulation of unprenylated Rap1a proteins in vitro. However, it is presently unclear whether N-BPs exert anti-tumor effects in bone independent of inhibition of osteoclast (OC) function in vivo. Therefore, we evaluated the impact of treatment with ZA on B16 melanoma bone tumor burden in irradiated mice transplanted with splenic cells from src(-/-) mice, which have non-functioning OCs. OC-defective mice treated with ZA demonstrated a significant 88% decrease in tumor growth in bone compared to vehicle-treated OC-defective mice. These data support an osteoclast-independent role for N-BP therapy in bone metastasis.
Department of Medicine, Division of Molecular Oncology, Washington University School of Medicine, St Louis, MO 63110, USA.
Angela C
AC
Hirbe
Anke J
AJ
Roelofs
Desiree H
DH
Floyd
Hongju
H
Deng
Stephanie N
SN
Becker
Lisa G
LG
Lanigan
Anthony J
AJ
Apicelli
Zhiqiang
Z
Xu
Julie L
JL
Prior
Mark C
MC
Eagleton
David
D
Piwnica-Worms
Michael J
MJ
Rogers
Katherine
K
Weilbaecher
D000818:Animals; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004164:Diphosphonates / Q000008:administration & dosage / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D051228:Geranyltranstransferase / Q000378:metabolism; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009362:Neoplasm Metastasis / Q000517:prevention & control; D010010:Osteoclasts / Q000187:drug effects / Q000473:pathology*; D017368:Protein Prenylation / Q000187:drug effects; D000077211:Zoledronic Acid
D004164:Diphosphonates; D007093:Imidazoles; D000077211:Zoledronic Acid; D051228:Geranyltranstransferase