Fig. 3: AKR1B1-mediated endogenous fructose metabolism contributed to glycolysis in cancer cells both in vitro and in vivo.

A The strategy of establishment of in vitro and in vivo models and implementation of stable isotope tracer investigation in this study. Heatmaps showing the isotope tracing results by using¹³C-labeled glucose as a tracer in A549 (B) and U87 (C) cells with or without AKR1B1-KO. The cells were cultured in glucose-free DMEM medium containing 10% dialyzed FBS supplemented with 25 mM ¹³C-glucose for 24 h, harvested with trypsin and followed by metabolic flux analysis (n = 3). D Metabolite quantification for ¹³C-glucose, ¹³C-lactate, ¹³C-fructose, and ¹³C-pyruvate from A549 and U87 cells with or without AKR1B1-KO. The cell culture method is the same as described in (B) (n = 3). E Metabolite quantification for ¹³C-glucose, ¹³C-lactate, ¹³C-fructose, and ¹³C-pyruvate from HCT116 and BxPC3 cells with or without AKR1B1 overexpression. The cell culture method is the same as described in (B) (n = 3). F Isotope tracing analysis by using ¹³C-labeled glucose as a tracer in A549 (n = 8) and U87 (n = 4) xenograft tumors with or without AKR1B1-KO. Data are represented as mean ± SEM. *: t test P < 0.05; #: t test P < 0.01.