Abstract
Minodronic acid (YM529) is a third-generation bisphosphonate (BP) that has been shown to directly and indirectly prevent proliferation, induce apoptosis, and inhibit metastasis of various types of cancer cells. In this study, we have investigated the therapeutic efficacy of YM529 against bladder cancer, both in vitro and in vivo. YM529 inhibited geranylgeranylation as well as farnesylation and reduced the growth of all seven bladder cancer cell lines in a dose- and time-dependent manner in vitro. YM529 demonstrated a good synergistic or additive antiproliferative effect when administered in combination with cisplatin or paclitaxel. Immunohistochemical study revealed YM529 inhibited the prenylation of Rap1A in vivo. YM529 administered systemically did not markedly inhibit the growth of visceral metastases but it showed a significant anticancer effect on bone metastases monitored by an in vivo imaging system. Moreover, intravesical YM529 demonstrated significant growth inhibition in a bladder cancer orthotopic model. No adverse effects were associated with the systemic as well as the intravesical treatment regimens. In conclusion, our study suggests that YM529 may be a potent anticancer agent for bladder cancer. The efficacy and safety of this BP as an agent for combination chemotherapies against bladder cancer should be verified by early-phase clinical trials.