Differential effects of bisphosphonates on breast cancer cell lines.

Bisphosphonates may induce direct anti-tumor effects in breast cancer cells in vitro. In this study, six bisphosphonates were administered to three breast cancer cell lines. Cell proliferation was measured by quantification of the expression of Cyclin D1 mRNA. Apoptosis was determined by flow cytometry of a DNA fragmentation assay. We demonstrated that bisphosphonates have direct effects on cell proliferation and apoptosis in different breast cancer cell lines. However, not all bisphosphonates act equally on breast cancer cells in vitro. Zoledronate seems to be the most potent of the six bisphosphonates. This in vitro study showed that bisphosphonates possess promising anti-tumor potential.