Xenograft mouse model and treatment

Female 5-week-old nude mice (Vital River, China) were housed in a sterile environment with micro isolator cages and allowed access to water and chow ad libitum. HCT-116 WT was harvested, and 1 × 10⁶ cells in 0.2 ml of McCoy’s 5A modified medium were implanted subcutaneously into the back of athymic nude female mice. Mice were treated with daily with SC66 at 25 mg/kg by i.p. injection every other 3 days for 15 days, whereas the control mice were administered vehicle. Volume was calculated by the formula of 0.5 × length × width². Mice were euthanized when tumors reached ~ 1.0 cm³ in size. Tumors were dissected and fixed in 10% formalin and embedded in paraffin. All mice were housed and maintained under specific pathogen-free (SOPF) conditions. All animal studies were in accordance with institutional guidelines and approved by the Use Committee for Animal Care.