CLK3 promotes de novo purine synthesis and CCA progression through enhancing the stabilization and nuclear translocation of c-Myc. (A and B) The effects of introducing c-Myc on shCLK3-mediated purine metabolites in HuCCT1 cells. (C) The effect of CLK3 knockdown or overexpression on c-Myc mRNA abundance in HuCCT1 cells (left) or HCCC9810 cells (right), respectively. (D and E) The c-Myc half-life in HuCCT1 (D) and HCCC9810 (E) cells treated using CHX (20 µg/ml). (F) The effect of MG132 on c-Myc degradation in HuCCT1 cells. (G) The impacts of CLK3 knockdown or overexpression on the subcellular localization of c-Myc in HuCCT1 (i) or HCCC9810 (ii) cells were analyzed by Western blot and quantified. *, P < 0.05; **, P < 0.01; ***, P < 0.001; #, not significant. Data are representative of three independent experiments with similar results (D and E) or from three independent experiments (A–C, F, and G; mean ± SEM). P values were calculated using unpaired Student’s t test (C and G) or one-way ANOVA (A, B, and F). Cyto, cytoplasmic; KD, knockdown; Nucl, nuclear; PPP, pentose phosphate pathway; AMP, adenosine monophosphate; GMP, guanosine monophosphate; IMP, inosine monophosphate; TUBA, alpha tubulin.