Fig. 1

Western blotting revealed that Cal-27 supernatant induced elevated expression of fibroblast activation proteins α-SMA, FAP, and PDGFR-β (A, B). Protein microarray analysis demonstrated a significant 5.7-fold increase in PDGF-BB in this supernatant compared with that in the hOMK supernatant (D, E). This increase was further verified by ELISA (C). Western blotting also demonstrated that the use of a PDGF-BB antibody blocker and PDGFR-β receptor inhibitor attenuated the expression of fibroblast activation protein α-SMA induced by Cal-27 supernatant from tongue squamous carcinoma cells (F, H). Conversely, PDGF-BB induced fibroblast activation with high expression of α-SMA (G, I). In clinical specimens of tongue squamous carcinoma, PDGF-BB was found to be highly expressed in tumor cells (J, L), while PDGF-BR was mainly expressed in the tumor mesenchyme (K, M) (n = 24 adjacent tissue samples, 84 cancer tissue samples; magnification, 200× with a scale bar of 100 μm and magnification, 400× with a scale bar of 50 μm, respectively). The statistical analyses indicated significant differences (*P < 0.05, **P < 0.01, ***P < 0.001)