SOD2 deregulation enhances migration, invasion and has poor prognosis in salivary adenoid cystic carcinoma

This study aimed to investigate the role of SOD2 in the progression and metastasis of salivary adenoid cystic carcinoma (SACC). We analyzed the expression of SOD2 in 50 SACC patients. Then, the effects and mechanism of SOD2 on cell metastasis in a pair of different metastatic potential cell lines was investigated. SOD2 was deregulated in patients with SACC. Up-regulation of SOD2 was associated with distant metastasis and reduced overall survival and disease free - survival. Compared to SACC-83 cells (lower metastasis ability), SACC-LM cells (higher metastasis ability) had higher SOD2 activity and intracellular H2O2 concentrations, and protein levels of pERK1/2 and Slug, but had similar catalase protein level and activity. In SACC-LM, reducing the expression of SOD2 by SiRNA inhibited the metastasis ability and reduced the SOD2 activities, intracellular H2O2 concentrations, and protein levels of pERK1/2 and Slug. These effects were revised in SACC-83 after SOD2 overexpression. Moreover, in SACC-83, treated with H2O2, the metastasis was enhanced accompanied by increased protein levels of pERK1/2 and Slug. We confirmed that SOD2 play an important role in the development and prognosis of SACC and SOD2-dependent production of H2O2 contributes to metastasis of SACC through the ERK-Slug signaling pathway.