Zoledronic acid alters hematopoiesis and generates breast tumor-suppressive bone marrow cells

Breast Cancer Res. 2017 Mar 6;19(1):23. doi: 10.1186/s13058-017-0815-8.


Background: The bone-targeting agent zoledronic acid (ZOL) increases breast cancer survival in subsets of patients, but the underlying reasons for this protective effect are unknown. ZOL modulates the activity of osteoclasts and osteoblasts, which form hematopoietic stem cell niches, and therefore may affect hematopoietic cells that play a role in breast cancer progression.

Method: Immunocompetent and immunocompromised strains of mice commonly used for breast cancer research were injected with a single, clinically relevant dose of ZOL (100 μg/kg) or vehicle control. The effects of ZOL on the bone marrow microenvironment (bone volume, bone cell number/activity, extracellular matrix composition) were established at various time points following treatment, using micro-computed tomography (μCT) analysis, histomorphometry, ELISA and immunofluorescence. The effects on peripheral blood and bone marrow hematopoietic progenitor populations were assessed using a HEMAVET® hematology analyzer and multicolor flow cytometry, respectively. Tumor support function of bone marrow cells was determined using an in vivo functional assay developed in our laboratory.

Results: Using multiple mouse strains, we observed transient changes in numbers of hematopoietic stem cells, myeloid-biased progenitor cells, and lymphoid-biased cells concurrent with changes to hematopoietic stem cell niches following ZOL administration. Importantly, bone marrow cells from mice treated with a single, clinically relevant dose of ZOL inhibited breast tumor outgrowth in vivo. The ZOL-induced tumor suppressive function of the bone marrow persisted beyond the time point at which numbers of hematopoietic progenitor cells had returned to baseline.

Conclusions: These findings provide novel evidence that alterations to the bone marrow play a role in the anti-tumor activity of ZOL and suggest possibilities for capitalizing on the beneficial effects of ZOL in reducing breast cancer development and progression.

Keywords: Bisphosphonate; Hematopoiesis; Hematopoietic stem cell niches; Hematopoietic stem cells; Tumor-suppressive bone marrow cells; Zoledronic acid.

MeSH terms

  • Animals
  • Bone Density Conservation Agents / pharmacology*
  • Bone Marrow / diagnostic imaging
  • Bone Marrow / metabolism
  • Bone Marrow / pathology
  • Bone Marrow Cells / drug effects*
  • Bone Marrow Cells / metabolism*
  • Bone and Bones / diagnostic imaging
  • Bone and Bones / metabolism
  • Bone and Bones / pathology
  • Breast Neoplasms / blood*
  • Breast Neoplasms / drug therapy
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Colony-Forming Units Assay
  • Diphosphonates / pharmacology*
  • Disease Models, Animal
  • Extracellular Matrix
  • Female
  • Hematopoiesis / drug effects*
  • Hematopoietic Stem Cells / drug effects
  • Hematopoietic Stem Cells / metabolism
  • Humans
  • Imidazoles / pharmacology*
  • Leukocyte Count
  • Mice
  • Neovascularization, Pathologic / drug therapy
  • Neovascularization, Pathologic / metabolism
  • Osteoblasts / drug effects
  • Osteoblasts / metabolism
  • Osteoclasts / drug effects
  • Osteoclasts / metabolism
  • X-Ray Microtomography
  • Zoledronic Acid


  • Bone Density Conservation Agents
  • Diphosphonates
  • Imidazoles
  • Zoledronic Acid