Lidocaine enhances the effects of chemotherapeutic drugs against bladder cancer

This study aimed to investigate whether lidocaine, alone or in combination with other chemotherapeutic agents, inhibits the growth of human bladder cancer cells in vitro and orthotopically transplanted bladder tumors in vivo. The effects of lidocaine (1.25, 2.5 or 5 mg/mL), mitomycin C (MMC, 0.66 mg/mL), pirarubicin (0.75 mg/mL) and Su Fu’ning lotion (SFN, 0.0625 mg/mL) on the proliferation of human bladder cancer (BIU-87) cells were studied using the MTT assay. A Balb/c nude mouse model of bladder cancer was developed by orthotopic transplantation of BIU-87 cells, and the effects of intravesical instillation of lidocaine and MMC on bladder wet weight (a measure of tumor size) and survival (over 60 days) were studied. Lidocaine inhibited proliferation of BIU-87 cells in a concentration-dependent manner and (when given in combination) enhanced the actions of each of the other antiproliferative agents. In tumor-bearing mice, MMC alone had no effect on mean survival or bladder wet weight. However, the combination of 0.66 mg/mL MMC and 5 mg/mL lidocaine prolonged survival (from 34.62 ± 6.49 to 49.30 ± 6.72 days; n = 8, P < 0.05) and reduced bladder wet weight (from 68.94 ± 53.61 to 20.26 ± 6.07; n = 8, P < 0.05). Intravesical instillation of lidocaine combined with other chemotherapeutic agents potentially could be an effective therapy for bladder cancer.