Format

Send to

Choose Destination
Br J Cancer. 2010 Mar 16;102(6):1010-7. doi: 10.1038/sj.bjc.6605579. Epub 2010 Feb 16.

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

Author information

1
Academic Unit of Clinical Oncology, Cancer Research Centre, Weston Park Hospital, Sheffield, UK. h.l.neville-webbe@sheffield.ac.uk

Abstract

BACKGROUND:

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.

METHODS:

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.

RESULTS:

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.

CONCLUSION:

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.

PMID:
20160726
PMCID:
PMC2844031
DOI:
10.1038/sj.bjc.6605579
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Nature Publishing Group Icon for PubMed Central
Loading ...
Support Center