Fig. 7. Sikokianin C inhibits tumor growth in human colon cancer xenograft models. Nude mice with established subcutaneous HT29 human colon tumors were injected s.c. with aminooxyacetic acid (AOAA, positive control), sikokianin C or the vehicle control. All regimens were administered daily for 6 d with a 1 d drug holiday for a total number of 12 treatments. (A) The macroscopic appearance of tumors in BALB/c nude mice 12 days after treatment (n = 6 per group). Antitumor effect of sikokianin C and AOAA against established xenograft tumors in nude mice. On day 28, all the mice were killed, and tumors were excised. (B and C) Sikokianin C treatment significantly reduced the tumor volume after the s.c. injection of HT29 cells in human tumor xenograft models. Each data point represents the mean ± SD (n = 6). (D) Mean tumor weight (±SD). ***p < 0.001.