Tumor-inhibitory effect and immunomodulatory activity of fullerol C60(OH)x

The tumor-inhibitory effect of C-60(OH)(x) was tested on the murine H22 hepatocarcinoma model. Doses of 0.2 and 1.0 mg kg(-1) body weight both showed significant antitumor activity with tumor inhibition rates of 31.9 and 38.4%, respectively, when mice were treated for 17 consecutive days. The damnification of liver was prominently reduced. Furthermore, histological examination indicated that an envelope of fibroblasts and lymphocytes was formed surrounding tumor tissues in the C-60(OH)(x)-treated group, which inhibited the infiltration of tumor to the neighboring normal skeleton muscle tissues. To understand the antitumor mechanism, the immunomodulatory activity of C-60(OH)(x) was investigated. The results indicate that C-60(OH)(x) enhances the phagocytosis of peritoneal macrophages and elevates the activity of arginase and acid phosphatase in vivo. The tumor necrosis factor alpha production of C-60(OH)(x)-treated macrophages also increases in vitro. These results suggest that C-60(OH)(x) can enhance the innate immunity of tumor-bearing mice, and therefore inhibits growth of the tumor.