Fig. 1: Altered amino acid metabolism during TGF-β-induced epithelial–mesenchymal transition (EMT).

a Venn diagram representing metabolic pathways that were significantly altered in TGF-β-stimulated A549, HCC827, or H358 cells compared to those in unstimulated cells. Cells were cultured in the presence of 2 ng/mL TGF-β for 2–5 weeks to induce EMT. Metabolite levels were detected by capillary electrophoresis time-of-flight mass spectrometry. Pathway significance was assessed using P values and false discovery rates (<0.05). The light gray-shaded rows in the table indicate the pathways of amino acid metabolism. b and c Alteration of amino acid metabolism in A549 cells during TGF-β-induced EMT. b Heat map showing the time-course of amino acid levels in A549 cells stimulated with or without 5 ng/mL TGF-β (n = 4) for 24, 48, and 72 h. Metabolite levels in each sample were converted to a fold-change relative to average metabolite level of the paired non-stimulation. Red and blue indicate higher and lower levels, respectively, of metabolites in TGF-β-stimulated cells compared to those in the unstimulated cells (white). c The metabolites indicated by red or blue on the map for amino acid metabolism were significantly up- or down-regulated by TGF-β treatment for 72 h, respectively.