Areca quid chewing enhances the expression of salivary matrix metalloproteinase-9

Background and Purpose. The effects of areca quid (AQ) consumption on salivary matrix metalloproteinases (MMPs) which may participate in tumor invasion and metastasis remains unclear. This stud), assessed the change in salivary MMP-9 protein levels 2 hours after 5-minute AQ chewing stimulation (AQCS) in non-AQ users and the expression profile of this proteinase in saliva and tumor specimens of oral squamous cell carcinoma (OSCC) patients with a history of AQ use. Methods: MMP-9 transcript was analyzed by reverse transcription-polymerase chain reaction. MMP-9 protein level was measured by both Western blot and gelatin zymography. Results: The protein level of salivary MMP-9 was 3.1- to 8.9-fold enhanced 2 h after AQCS in 3 healthy volunteers as revealed by Western blot and zymography. As a control, gum chewing did not significantly change salivary MMP-9 protein level. Expression of MMP-9 transcript was found in 25 of 28 OSCC specimens and significantly correlated with cervical lymph node metastasis (p = 0.037). All of the 8 tested OSCC tissue homogenate samples available and all 12 saliva samples from 12 oral tumor outpatients were positive for MMP-9 protein. Conclusions. Elevation of MMP-9 may be one of the net effects of AQCS in vivo, which may play a role in the pathogenesis of oral mucosal lesions. Furthermore, the association of MMP-9 expression with neck-lymph-node metastasis may imply a significant role of MMP-9 in the progression of OSCC among patients with a history of AQ use in Taiwan.