Figure 1: Release of exosomes by tumour cells depends on aerobic glycolysis.

(a–c) Isolated exosomes from A549 cells assessed by transmission electron microscopy (a), WB (b) and NTA (c). The lower right image in a represents the immune-gold labelling of CD63 in an exosome. (d) Tumour cells release more exosomes than non-tumour cells. (e) Positive correlation between exosome secretion and aerobic glycolysis. (f) Linear regression between glucose uptake (r₁²=0.83) and lactate level (r ₂²=0.81). (g) Release of exosomes is dependent on cellular aerobic glycolysis. Cells were treated with shikonin (1 μM) or tumour necrosis factor α (5 ng ml⁻¹) to inhibit or promote aerobic glycolysis. Exosome concentration was measured 24 h post-treatment. (h) Effect of EGF and OA on cell aerobic glycolysis. Note that EGF (10 ng ml⁻¹), an enhancer of exosome release, increases aerobic glycolysis, while OA (10 μg ml⁻¹), an inhibitor of exosome release, decreases aerobic glycolysis. (i) EGF and OA regulate A549 cell exosome release via altering cellular aerobic glycolysis. Data are presented as the mean±s.e.m. and represent at least three independent experiments with three replicates per data point. NS, no significance. *P<0.05, **P<0.01, **P<0.001 as determined by the one-way ANOVA test.