Sonodynamically-induced anticancer effects by functionalized fullerenes.

BACKGROUND Functionalized fullerenes, such as polyhydroxy fullerenes (PHF), have attracted particular attention due to their water solubility and their potential application in tumor imaging and therapy as carbon nanomaterials. In this study, the sonodynamically-induced antitumor effect of PHF was investigated. MATERIALS AND METHODS Sonodynamically-induced antitumor effects of PHF in combination with ultrasound were investigated using isolated sarcoma 180 cells and solid tumor from colon 26 carcinoma cells. RESULTS The cell damage induced by sonication was enhanced by two-fold in the presence of 80 μM PHF. Histidine significantly inhibited this enhancement. This inhibitory effect suggests that the sonodynamically-induced antitumor effect was mediated by sonodynamically-generated reactive oxygen species. The combined treatment of ultrasonic exposure with PHF suppressed the growth of implanted colon 26 tumors. The destruction of tumor tissue was observed with the ultrasonic treatment in combination with PHF, while neither the treatment with PHF alone nor that with ultrasound alone caused necrosis. CONCLUSION These results suggest that PHF is a potential sonosensitizer for sonodynamic treatment of solid tumors.