Inhibition of prostate cancer growth by vinblastine and tamoxifen

Hormone refractory prostate cancer continues to be an aggressive and fatal disease. Agents which inhibit microtubule function have been found to be cytotoxic to prostate cancer cells in preclinical and clinical settings. It was the aim of this study to assess the activity of tamoxifen and vinblastine, two microtubule inhibitors, in hormone refractory prostate cancer. In clinically achievable concentrations, the combination of tamoxifen and vinblastine was cytotoxic to both Dunning rat prostate adenocarcinoma cell line MAT‐LyLu (MLL) and human prostate cancer cells (PC‐3). In cell cycle analysis assays, tamoxifen and vinblastine inhibited cell cycle transit. In vivo, these two agents inhibited the growth of implanted MLL cells. It appears that tamoxifen and vinblastine may be effective agents for the treatment of patients with hormone refractory prostate cancer.