2.11. The xenograft mouse model of HCT116 cells and patient‐derived xenograft mouse model

HCT116 cells (3 × 10⁶ per mouse) were subcutaneously implanted into male BALB/c nude mice (6‐week‐old) to establish the growth mouse model. After the tumor grew to 200 mm³, a total of 35 mice were divided into 5 groups on average (n = 7): control group (DMSO), regorafenib group (25 mg/kg), YQ456 groups (25 and 50 mg/kg), and sgMYOF group (DMSO). The body weights and tumor volumes of mice were measured every 5 days.

The tumor tissues derived from two colorectal cancer patients were subcutaneously implanted into male BALB/c nude mice (6‐week‐old) to establish the patient‐derived xenograft (PDX) mouse model. After two consecutive subcutaneous passages of tumor tissues, about six tumor pieces (3 mm ³ ) per mouse were subcutaneously implanted into BALB/c nude mice. Finally, a total of 31 mice (12 tumor tissues from patient #1 and 19 tumor tissues from patient #2, respectively) were successfully modeled. When the tumor grew to 100 mm³, mice were divided into 4 groups: control group (DMSO, n = 6), regorafenib group (25 mg/kg, n = 7), and YQ456 groups (25 and 50 mg/kg, n = 7). The body weights and tumor volumes of mice were measured every 4 days.

During the two experiments, all mice were intraperitoneally injected with 50 μL drug or DMSO daily, except mice in the regorafenib group were treated by intragastric administration. The tumor volumes of mice were calculated by the following formula: length × width × width × 0.52. When the tumor volumes of mice reached 2000 mm³, mice were euthanized with carbon dioxide due to ethical consideration.