Nuclear Survivin expression is correlated with malignant behaviors of head and neck cancer together with Aurora-B

Abstract

Survivin belongs to the inhibitors of apoptosis (IAP) gene family and inhibits apoptosis. Besides its role as IAP, Survivin recently appears to function as a subunit of the chromosomal passenger complex (CPC) for regulating cell division with other CPC proteins including Aurora-B and INCENP. Nuclear Survivin is suspected to control cell division, whereas cytoplasmic Survivin is considered cytoprotective. Although there are several studies on Survivin expression and its function as inhibition of apoptosis, there is no study on Survivin function as a CPC and its correlation with other CPC proteins in head and neck squamous cell carcinoma (HNSCC). Here, therefore, we examined nuclear Survivin expression and its functional correlation with Aurora-B in HNSCC. High expression of Survivin was well correlated with Aurora-B expression in nuclear fraction of HNSCC cell lines and tissues. Moreover, nuclear Survivin expression was significantly correlated with Ki-67 and Aurora-B expression by immunohistochemistry. Notably, HNSCC cases with nuclear Survivin and Aurora-B expression exhibited marked malignant behaviors. Interestingly, both Survivin and Aurora-B knockdown inhibited cell growth and tumorsphere formation. Overall suggest that nuclear Survivin may be involved in tumor progression together with Aurora-B, and that Survivin and Aurora-B can be useful diagnostic markers and therapeutic targets.