Oral cancer cells enhanced glycolysis of fibroblasts. (A) α-smooth muscle actin (green) staining in NFs cultured alone and NFs co-cultured with UM1 cells. Magnification, ×50. Fibroblasts (NFs and CAFs) were co-cultured with oral squamous cell carcinoma cell lines (CAL27, UM1 and SCC25) respectively, for 48 h before harvest. (B) Reverse transcription-quantitative polymerase chain reaction analysis for the expression of a series of glycolytic genes in fibroblasts. Columns present the mean ± SD of triplicate determinations. (C) Western blot analysis of GLUT1, HK2, LDHA and MCT4 in NFs and CAFs. Densitometry was used to determine target gene/GAPDH ratios. Data are presented as the mean ± SD of three independent experiments. *P<0.05 and **P<0.01 vs. cells cultured alone. SD, standard deviation; NF, normal fibroblasts; CAFs, cancer-associated fibroblasts; GLUT1, glucose transporter 1; HK2, hexokinase 2; PFK, phosphofructokinase; PKM2, pyruvate kinase M2; LDHA, lactate dehydrogenase; MCT, mono-carboxylate transporter.