In the present study, we found that combined therapy with Asiatic acid (AA), a Smad7 agonist, and Naringenin (NG), a Smad3 inhibitor, effectively retrieved the balance between Smad3 and Smad7 signaling in the TGF-β-rich tumor microenvironment and thus significantly suppressed tumor invasion and metastasis in mouse models of melanoma and lung carcinoma. Here, SMAD3 is linked to lung carcinoma.