Combined effects of the bisphosphonate, zoledronic acid and the aromatase inhibitor letrozole on breast cancer cells in vitro: evidence of synergistic interaction.

Aromatase inhibitors are widely used in the treatment of oestrogen receptor-positive post-menopausal breast cancer. These patients may also be receiving the bisphosphonate, zoledronic acid (ZA) to prevent bone loss or reduce skeletal morbidity in the setting of advanced disease. The potential biological interaction of these two drugs in breast cancer has not been assessed.
Aromatase-expressing breast cancer cells were treated with letrozole and ZA either simultaneously or in sequence, and the resulting apoptosis was assessed by staining with Hoechst 33342 and propidium iodide and examined using a fluorescent inverted Leica DMIRB microscope and a UV filter.
We found that letrozole and ZA induce levels of apoptosis in breast cancer cells in vitro that are significantly greater compared with treatment with each drug alone. However, this potentially, synergistic relationship is drug-sequence dependent, occurring only when cells are treated with letrozole, followed by ZA. The converse sequence, or administering drugs simultaneously, induces levels of apoptosis no greater than each drug alone.
Owing to the enhanced anti-tumour efficacy of sequential drug administration, our findings may indicate that, for post-menopausal women who require treatment with letrozole, ZA should also be considered.
AuthorsH L Neville-Webbe, R E Coleman, I Holen
JournalBritish journal of cancer (Br J Cancer) Vol. 102 Issue 6 Pg. 1010-7 (Mar 16 2010) ISSN: 1532-1827 [Electronic] England
PMID20160726 (Publication Type: Journal Article)
Chemical References
  • Aromatase Inhibitors
  • Bone Density Conservation Agents
  • Diphosphonates
  • Imidazoles
  • Nitriles
  • Triazoles
  • zoledronic acid
  • letrozole
  • Algorithms
  • Antineoplastic Combined Chemotherapy Protocols (pharmacology)
  • Apoptosis (drug effects)
  • Aromatase Inhibitors (administration & dosage, pharmacology)
  • Bone Density Conservation Agents (administration & dosage, pharmacology)
  • Breast Neoplasms (pathology)
  • Cell Line, Tumor
  • Cell Proliferation (drug effects)
  • Cell Survival (drug effects)
  • Diphosphonates (administration & dosage, pharmacology)
  • Dose-Response Relationship, Drug
  • Drug Evaluation, Preclinical
  • Drug Synergism
  • Female
  • Humans
  • Imidazoles (administration & dosage, pharmacology)
  • Nitriles (administration & dosage, pharmacology)
  • Triazoles (administration & dosage, pharmacology)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research network!

Choose Username:
Verify Password: