Suppression of tumorigenicity and growth of NPC cells by berberine in vivo . (a) Berberine could suppress the tumor initiation and growth of C666-1 xenografts in mice models. 1 X 106 Tumor cells were injected subcutaneously into nude mice. Mice were either treated with berberine (low dose: 5 mg/kg or high dose: 10 mg/kg; i.p.) or treated with saline (as control) for every other two days. Both low and high dose of berberine could significantly suppress the tumor growth (p < 0.05) when compared to that of the control mice. (b) Individual growth curves of tumors in control and berberine-treated mice. The tumor sizes of individual mouse under control treatment (PBS-treated; n = 4), under low dose of berberine treatment (5 mg/kg berberine-treated; n = 5) and under high dose of berberine treatment (10 mg/kg berberine-treated; n = 5) were followed from 14 to 43 days post-injection of tumor cells. (c) The body weights of the mice within the treatment and control groups were comparable. The weights of the mice were recorded from the day of injection until 43 days post-infection of tumor cells. Both the control mice and berberine-treated mice showed a steady increase of body weight. Both 5 mg/kg and 10 mg/kg treatment of berberine did not cause drastic variation of body weight to the mice.