Fig. 2

Trp catabolism was activated in SERT-deleted CC in vivo. a AOM-DSS method was used to induce primary colon cancer in SERT-KO and SERT-WT mice. Mice were injected with AOM (10 mg/kg) and then subjected to three cycles of DSS (1.5%) in drinking water. Fourteen weeks after AOM injection, tumors were dissected and their volumes and number determined. b A linear graph of tumor incidence, average number and tumor area for each group (mean ± SD). Serum levels of Trp, Kyn and serotonin in SERT-WT and SERT-KO mice in normal and AOM/DSS group were detected using LCMS/MS. c RT-PCR for mRNA expression of the indicated Trp transporters and enzymes in tumor tissues of SERT-WT and SERT-KO mice. d The primary colon cancer model was established by AOM-DSS method in SERT-WT mice. One month after AOM injection, mice were randomly distributed into three groups (n = 7) including the control group, sertraline group and double tryptophan (DT) group. The DT diet (4 mg/kg Trp) or a relevant control diet (2 mg/kg Trp) were provided during normal drinking water without DSS. The sertraline group and control group were subjected to sertraline (30 mg/kg) or saline treatment. After 14 weeks, tumors were dissected and their volumes and number determined. The bar graph shows the tumor volumes and number in each group (mean ± SD). e RT-PCR for expression of the indicated Trp transporters and enzymes in tumor tissues of control and sertraline group mice. f Serum levels of Trp, Kyn of control and sertraline group were detected using LCMS/MS. *p < 0.05; ** p < 0.05; *** p<0.001 using Student’s test (two-tailed)