TGF-β1 Promotes Migration and Invasion of Salivary Adenoid Cystic Carcinoma

Salivary adenoid cystic carcinoma (SACC) is one of the most common subtypes of salivary gland carcinomas and frequently metastasizes to distant organs. However, little is known about the molecular mechanisms that promote SACC metastasis. In this study, we report that transforming growth factor (TGF)-beta 1 was highly expressed in the highly metastatic SACC-LM cell line as compared with its parental low-metastatic SACC-83 cell line. Exogenous addition of TGF-beta 1 induced Smad2 phosphorylation and promoted the migration and invasion of SACC-83 cells. Consistently, the inhibition of endogenous TGF-beta 1 signaling in SACC-LM cells by an inhibitor specific to the type I TGF-beta 1 receptor (T beta RI) suppressed cell migration and invasion. Moreover, we found that TGF-beta 1 expression was significantly increased in human primary SACC samples with metastasis. Taken together, our results suggest that TGF-beta 1 may play a crucial role in SACC metastasis.