Deregulation of nicotinamide N-methyltransferase and gap junction protein alpha-1 causes metastasis in adenoid cystic carcinoma

Abstract

Background/Aim: Adenoid cystic carcinoma (AdCC) is a malignant tumor that occurs in the salivary glands and frequently metastasizes. The aim of this study was to identify factors mediating AdCC metastasis. Materials and Methods: We established three AdCC cell lines by orthotropic transplantation and in vivo selection: parental, highly metastatic (ACCS-M-GFP), and lymph node metastatic (ACCS-LN-GFP) cells. Results: We examined the three cell lines. DNA microarray indicated significantly altered processes in ACCS-LN-GFP cells: particularly, the expression of nicotinamide N-methyltransferase (NNMT) was enhanced the most. NNMT is associated with tumorigenesis and is a potential tumor biomarker. Concomitantly, we found-significant down-regulation of gap junction protein alpha-1. We suggest that ACCS-LN-GFP cells acquire cancer stem cell features involving the up-regulation of NNMT and the loss of gap junction protein alpha-1, leading to epithelial-mesenchymal transition and consequent AdCC metastasis. Conclusion: NNMT is a potential biomarker of AdCC.