Downregulation of NONO induces apoptosis, suppressing growth and invasion in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies in China, and is associated with high morbidity and mortality. However, the molecular mechanisms that control ESCC tumorigenicity and metastasis remain unclear. Here, we report that the RNA splicing factor, NONO, is an important regulator of ESCC growth, apoptosis and invasion. NONO protein levels were dramatically upregulated in ESCC when compared with that in adjacent benign esophageal squamous epithelium. Particularly, NONO expression was statistically higher in tumors with greater tumor invasion depth. Using multiple ESCC cell models, we further showed that NONO depletion using siRNA significantly inhibited proliferation, invasion, and promoted apoptosis of ESCC cells. In addition we found that knockdown of NONO could reduce protein levels of phosphorylated Akt and Erk1/2. Our findings suggest that NONO plays a potent role in multiple biological aspects of ESCC through activation of the Akt and Erk1/2 signaling pathways. Taken together, our findings suggest that NONO might play an important role in promoting tumorigenesis of ESCC. It may provide a promising approach to prevent the progress of ESCC.