Fig. 7: SIRT5 promotes CRC growth by activating TKT to sustain the nucleotide pool in vivo.

a, b A surgical orthotopic mouse model by injecting luciferase-transfected HCT116 cells stably expressing the non-target control (NTC) shRNA or SIRT5 shRNAs into the cecum of nude mice was generated. A bioluminescence imaging system was used to monitor tumor growth weekly, and mice were sacrificed 4 weeks after tumor implantation (a), measurements (photons/s) of tumor volume using live bioluminescence imaging at indicated times (b). (n = 5 mice per group). Values represent mean ± SEM. c Tumors from the two groups were dissected and photographed. (n = 5 mice per group). d, e Tumor volume (d) and weight (e) were measured on the last day of the experiment at autopsy. (n = 5 mice per group). f TKT activities in tumor lysates derived from orthotopically implanted CRC tumors were measured. (n = 5 mice per group). g R5P and nucleotide levels in orthotopically implanted tumors were measured by targeted metabolomics analysis. (n = 3 mice per group). h Western blotting of SIRT5, TKT, and γH2AX in orthotopically implanted CRC tumors. GAPDH served as a loading control. Values indicate means ± SD in (d–g), compared by the two-sided Student’s t test. i–l HCT116 cells under different conditions were injected subcutaneously into nude mice. Tumors from different groups were dissected and photographed (i, j), and tumor volume and weight were measured (k, l). (n = 8 mice per group). m R5P and nucleotide levels in tumor lysates derived from subcutaneous xenograft tumors. (n = 3 mice per group). n Immunoblotting of SIRT5, TKT, phospho-p53 (Ser15), and γH2AX proteins in subcutaneous xenograft tumor tissues under different treatments. o Representative TUNEL and γH2AX staining of subcutaneous xenograft tumors at day 21. Scale bar, 50 μm. Values represent mean ± SD. One-way ANOVA with Tukey’s multiple comparisons test for (k–m). ns not significant. Source data are provided as a Source Data file.