Induction of interleukin-6 by SPZ1-mediated Wnt5a signaling boosts progression of nasopharyngeal carcinoma cells.

Nasopharyngeal carcinoma (NPC) is a common malignancy in Southeast Asia, and in the Guangxi and Guangdong provinces of China. The spermatogenic transcription factor zip 1 (SPZ1) is a member of bHLH zip family, and promotes tumorigenesis in the liver, colon and breast tissues. However, the role of SPZ1 in the progression of NPC is unclear. In this study, we found that SPZ1 mRNA and protein levels were significantly upregulated in NPC tissues compared to the normal nasopharyngeal tissues. Furthermore, SPZ1 knockdown in NPC cell lines inhibited proliferation, epithelial-mesenchymal transition, migration, and invasion in vitro, and suppressed tumorigenesis in an in vivo model. On the other hand, SPZ1 overexpression facilitated the growth of NPC cells. Mechanistically, SPZ1-driven progression of NPC is dependent on the Wnt5a/interleukin-6 (IL-6) signaling pathway. Consistent with this, IL-6 levels were significantly increased in NPC tissues and correlated positively with SPZ1 expression. Taken together, our findings suggest that SPZ1 mediates NPC progression through Wnt5a/IL-6 signaling, and the SPZ1/Wnt5a/IL-6 axis is a potential therapeutic target for NPC.