Tumor inhibitory effects of intravesical Ganoderma lucidum instillation in the syngeneic orthotopic MB49/C57 bladder cancer mice model

Ganoderma lucidum (GL) has been traditionally used in oriental medicine as superior health tonic, and there are numerous scientific evidences of its antitumorigenic activities. To evaluate the intravesical chemopreventive effects of ethanol extract of GL (GLe) on bladder cancer. Intravesical therapy is defined as the direct instillation of a liquid drug into bladder through a catheter. Bacille Calmette-Guerin (BCG) solution is applied intravesically as a conventional immunotherapy for preventing recurrence of bladder cancer. By adopting the MB49/C57 bladder cancer mice model, an overall 60 MB49-implanted mice were randomized into 3 groups and treated according to 3 treatment arms, including GLe, BCG and PBS. Additionally, wild-type mice without MB49 cell inoculation and treated with PBS were used as the negative control group. Testing agents were instilled intravesically for 2 h and repeated after one week for evaluating the effects on preventing the tumor formation and growth. The treated-mice were closely monitored for major adverse effects. GLe demonstrated more potent cytotoxic effects than BCG on MB49 cells, although both in dose-dependent manner. In the MB49-implanted mice, 80 µg/ml GLe was shown to delay the tumor formation by one week, whereas the averaged tumor volume measured at endpoint was 3.6-fold and 4.6-fold smaller than that of the BCG or PBS, respectively. However, no significant effects were observed on body weight and hematuria. Current findings in mice suggested intravesical GLe therapy as an effective and safe chemopreventive strategy for inhibiting bladder tumor formation.