Combined effects of bisphosphonate and radiation on osteosarcoma cells.

UNLABELLED Antitumour effects of third-generation bisphosphonates (BPs), such as zoledronic acid (ZOL), and the combined effects of ZOL with other anticancer agents against osteosarcoma cells have been reported previously. The aim of this study was to identify further combined antitumour effects using BPs and radiation in osteosarcoma cell lines. MATERIALS AND METHODS Cell proliferation, cell cycle analysis, and nuclear morphology were examined in each osteosarcoma cell line divided into three groups (ZOL alone, radiation alone and the ZOL/radiation combination). RESULTS Combined therapy (low-concentration ZOL and low-dose radiation) had significant growth inhibitory effects compared to the use of ZOL or radiation individually. Flow cytometric analysis revealed an increase in cells in the sub-G(1) phase by combined treatment, and apoptotic cells were also observed. CONCLUSION These findings suggest that combination therapy using BPs and radiation may be a promising therapy for osteosarcoma, producing fewer side effects and complications in the near future.