The sonodynamic antitumor effect of methylene blue on sarcoma180 cells in vitro.

BACKGROUND Sonodynamic therapy (SDT) is a promising methodology for cancer treatment. Methylene blue (MB) is a phenothiazine dye that is widely used in clinical practice and can be administered intravenously. MATERIALS AND METHODS The sonodynamic antitumor effect of 1, 10 and 100 microM MB on sarcoma180 (S180) cells was investigated in vitro. RESULTS After ultrasound (US) exposure at 0.24 W/cm(2) for 30 seconds, survival rates of S180 cells in the presence of 10 and 100 microM MB were significantly lower than that of the control group. These effects were significantly inhibited by the addition of D-mannitol, but not by L-histidine or superoxide dismutase. Microvilli loss and blebbing on the surface of S180 cells were observed in the presence of 100 muM MB after US exposure. CONCLUSION MB has a sonodynamic antitumor effect on S180 cells in vitro and the hydroxyl radical appears to be the principal mediator of this effect.