5-FU resistant OS cells showed metabolic reprogramming. (A-C) The 5-FU sensitivity of HCT-116/5-FU(A), SW480/5-FU (B), and SW620/5-FU (C) cells and parental cells after treated with increasing concentrations of 5-FU for 24 h. (D-F) The ATP generation (D), glucose consumption (E), and generation of lactate (F) in CRC parental and 5-FU resistant cells. (G-I) Variation of OCR was determined in HCT-116/5-FU(G), SW480/5-FU (H), SW620/5-FU (I) cells and parental cells, respectively. Experiments were performed in six replicates. (J-L) HCT-116/5-FU(J), SW480/5-FU (K), SW620/5-FU (L) cells were pretreated with 2-DG (10 mM) or OX (10 mM) for 90 min and then treated with increasing concentrations of 5-FU for 24 h. Data are presented as means ± SD of three independent experiments. ** p < 0.01 compared with control; NS, no significant.