SMAD4 modulates multiple kinase pathways and influences transcriptional factors expression. (A) Restoration of SMAD4 results in a marked increase of p38 MAPK activation, but significantly attenuated the phosphorylation (activation) of EGFR and its downstream signals p44/42 (MEK) and Akt pathways in PDAC cells. (B) SMAD4 affects the expression transcriptional factors in PDAC cells. Total protein extracted from indicated cells were lysed for Western blot analysis. Western blots were then performed with the indicated antibodies. β-actin was served as an internal control.