The Pseudogene PTTG3P Promotes Cell Migration and Invasion in Esophageal Squamous Cell Carcinoma

Pseudogenes are pivotal funtional non-coding RNAs in tumorigenesis. Cumulative evidences have shown that pituitary tumor-transforming 3, pseudogene (PTTG3P), serves as an oncogene in multiple human cancers. However, its expression pattern, biological function, and potential targets in esophageal squamous cell carcinoma (ESCC) remain unknown. Here, by quantitative real-time polymerase chain reaction (qRT-PCR) in 50 cases of ESCC, we found that the expression of PTTG3P, PTTG1 and PTTG2 in esophageal squamous cancer tissues and cell lines were significantly higher than their normal counterparts (P<0.01). Spearman correlation analysis showed that the PTTG3P expression was positively correlated with the PTTG1 and PTTG2 expression in ESCC tissue samples (P<0.05). Additionally, the high expression of PTTG3P in ESCC was significantly correlated with tumor depth, lymph node invasion and TNM stage (P<0.05). We also assessed the function of PTTG3P in vitro by gain-of-function studies. Results showed that enhanced expression of PTTG3P stimulated the migration and invasion of ESCC cells, and promoted the expression level of PTTG1 and PTTG2 in vitro. Furthermore, PTTG3P fulfilled its oncogenic functions by positively regulating its parent gene PTTG1 and PTTG2. Overall, our study indicated that PTTG3P is distinctly overexpressed and exhibited oncogenic role in a PTTG1 and PTTG2 mediated manner in ESCC.