Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer, and it has been steadily increasing in worldwide. Pituitary tumor transforming gene 1 (PTTG1) has been known as oncogene in a verity of cancers. Nevertheless, the expression and role of PTTG1 in OSCC progression remains largely unexplored. In this study, clinical datasets were analyzed to assess the genetic impact of PTTG1 on OSCC progression and to identify its functional roles in OSCC cell lines. We analyzed the expression of PTTG1 in head and neck squamous cell carcinoma (HNSC) and OSCC using databases form the Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO). To investigate the effect of PTTG1 on proliferation and migration abilities in OSCC cell lines, following the knockdown of PTTG1 in HSC-2 and SCC-9 cell lines, we analyzed the proliferation and metastatic abilities of OSCC cells using EdU and Boyden chamber assays. Our database analysis revealed that PTTG1 was significantly overexpressed in tumor tissues compared to normal tissues. Moreover, its expression correlated with clinical parameters of OSCC. In vitro experiments demonstrated that depletion of PTTG1 suppressed the ability of cell proliferation and migration in both HSC-2 and SCC-9 cell lines. In conclusion, our study suggests that PTTG1 may act as an oncogene in OSCC. These findings provide new insights into the mechanisms and clinical implications of PTTG1 expression in OSCC patients.

Human pituitary tumor transforming gene 1 (PTTG1), which is a newly identified proto-oncogene, is highly expressed in normal pituitary tissues containing proliferating cells and in several cancers. Also, PTTG1 has been known as a securin to involve in the regulation of c ell-cycle and in t he p rogression o f tumor. B u t the effect o f PTTG1 in o ral squamous cell carcinoma (oral SCC) h as not b een studied yet. The objective of this study is to analyze the expression of PTTG1 in oral SCC cell lines (YD-10B and YD-15) and to evaluate the effect of PTTG1 on oral SCC cell lines for the migration effect by PTTG1 siRNA treatment. Western blot, migration assay, and zymography were performed to evaluate the effects of PTTG1 on the expression of MMP-2/-9 and migration activity after PTTG1 siRNA treatment. PTTG1 was expressed in oral SCC cells lines, otherwise, significantly decreased after PTTG1 siRNA treatment. There is no difference in expression of MMP-2 regardless of PTTG1 siRNA treatment. However, the enzyme activity of MMP-9 was significantly decreased. In addition, the migration activities of oral SCC cells were significantly decreased after PTTG1 siRNA treatment (p<0.001). These results suggested that the down-regulated PTTG1 could inhibit the migration of human oral SCC cells through the low MMP-9 expressions. Therefore, these findings provide a useful guideline for the migration mechanism of oral SCC depend on PTTG1 expression.