The DLD-1 cell suspension (4 x 10⁶ cells/200 ul) was injected subcutaneously into the right dorsal flank of 5-week-old male BALB/c nude mice (Charles River, China). The mice were randomly divided into four groups (5 mice/group): 1) the control group, 2) the RSL3 group, 3) the cetuximab group, and 4) the RSL3 + cetuximab group. Both RSL3 (5 mg/kg) and cetuximab (13 mg/kg) were administered by intraperitoneal injection in a volume of 100 ul once per day. The tumour volume was calculated as 0.5 x length x width2. After 17 days of treatment, the mice were sacrificed, and the tumours were removed. Then, tumour tissue obtained from the different treated groups was subjected to western blotting and immunohistochemical experiments.

The DLD-1 cell suspension (4 x 10⁶ cells/200 ul) was injected subcutaneously into the right dorsal flank of 5-week-old male BALB/c nude mice (Charles River, China). The mice were randomly divided into four groups (5 mice/group): 1) the control group, 2) the RSL3 group, 3) the cetuximab group, and 4) the RSL3 + cetuximab group. Both RSL3 (5 mg/kg) and cetuximab (13 mg/kg) were administered by intraperitoneal injection in a volume of 100 ul once per day. The tumour volume was calculated as 0.5 x length x width2. After 17 days of treatment, the mice were sacrificed, and the tumours were removed. Then, tumour tissue obtained from the different treated groups was subjected to western blotting and immunohistochemical experiments.

The PDX models used in this study were derived from patients (CRC0078 and CRC0121) carrying a quadruple wild-type (KRAS,NRAS,BRAF, andPIK3CA) colorectal tumor. Established tumors (average volume 300 or 500 mm³, as indicated) were treated with the following regimens, either single-agent or in combination: VitC (Sigma, 4 g/kg, intraperitoneal, daily-5 days per week), cetuximab (Merck, 10 mg/kg, intraperitoneal, twice weekly).

5-week-old female BALB/c nude were purchased from Shanghai Slac Laboratory Animal Co., Ltd. HCT116-luc cells were digested and washed by cold PBS for three times, and the final concentration was 2.5 x 10⁶/ml in cold PBS. A volume of 100 ul cell suspension was injected subcutaneously into right dorsal flank of mice. When the tumor tissue in the subcutaneous was macroscopic, the tumor tissues were dissected and embedded into the mesentery of mice.