Fig. 5

CD26 is an upstream regulator involved in apigenin (API)-regulated Akt activation and the epithelial-to-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC) cells. a Western blot analysis of CD26 expressions in A549 cells overexpressing Snail (left panel) and Slug (right panel). b Western blot analysis of CD26 expressions in A549 cells which were transiently transfected with a vector control (A549/Neo) or myr-Akt (A549/myr-Akt) followed by API or vehicle treatment for an additional 24 h. c A549 and H1975 cells were infected with a lentivirus carrying CD26 shRNA or shGFP (shCtrl) and subjected to a Western blot analysis to determine expressions of CD26, p-Akt, and EMT-related regulators (vimentin, fibronectin, Snail, and Slug). Quantitative results of p-Akt and other indicated proteins were respectively adjusted to total Akt protein and β-actin protein levels. d Combined expressions of high CD26 and high Akt proteins correlated with the recurrence-free survival of patients with lung carcinoma. The p value refers to a comparison between CD26^high/Akt^high and other groups (CD26^high/Akt^low, CD26^low/Akt^high, or CD26^low/Akt^low)