Colon tumor mouse model

To generate AOM-DSS-induced colon tumors in mice, 6-week-old C57BL/6 male mice were intraperitoneally injected with AOM (Sigma-Aldrich, USA) at a concentration of 10 mg/kg body weight. After 5 days of AOM injection, the mice were fed drinking water supplemented with 2.5% DSS (molecular weight 36,000-50,000, MP Biomedicals, USA) for 5 days, followed by regular water for a predetermined number of days. After three cycles of DSS treatment, the mice were fed regular water for 28 days. The mice were randomly divided into six groups, of 6 mice per group. Twenty-eight days after the third round of DSS treatment, the mice were enema- or gavage-treated with 100 μL of PBS, miR-31i/Cur, PS-TP-miR-31i/Cur, sOKGM-PS-miR-31i, sOKGM-PS-Cur or sOKGM-PS-miR-31i/Cur (1.25 mg/mL, equivalent to the PS concentration) once daily for 14 consecutive days. After the treatment, the mice were sacrificed for sample collection. The tumor numbers and volumes were evaluated as described above.