SMAD4 and lung carcinoma: In addition, kaempferol (10, 25, 50 μM) treatment of A549 lung cancer cells, followed by TGFß‐1 stimulation, resulted in phosphorylation of Smad3 (although phosphorylation at residue Thr179 was down‐regulated) and the formation and nuclear translocation of Smad4 complexes.143