Down-regulation of NcRAN, a Long Non-coding RNA, Contributes to Colorectal Cancer Cell Migration and Invasion and Predicts Poor Overall Survival for Colorectal Cancer Patients

Accumulating evidence has indicated that long non-coding RNAs (lncRNAs) play critical roles in regulating cellular processes, such as cell growth and apoptosis, as well as cancer progression and metastasis. ncRAN (non-coding RNA expressed in aggressive neuroblastoma) was previously shown to be dramatically up-regulated and associated with poor prognosis in human neuroblastoma. This lncRNA also plays an important role in bladder cancer growth and invasion. Colorectal cancer (CRC) progression typically follows a complex cascade from primary malignancy to distant metastasis, but whether the aberrant expression of ncRAN in CRC is associated with malignancy, metastasis or prognosis remains unknown. In this study, we demonstrated that ncRAN expression is significantly down-regulated in tumor tissue and CRC cell lines compared with adjacent normal tissue and a normal intestinal mucous cell line. Reduced expression of ncRAN was detected in poorly differentiated or undifferentiated tumors and in tumors with liver metastases. Kaplan-Meier analysis indicated that patients with lower ncRAN expression have a worse overall survival. Moreover, multivariate analysis revealed that decreased expression of ncRAN is an independent predictor of overall survival. Our experimental data indicated that ncRAN mediates the in vitro migration and invasion of CRC cells. Together, these results suggest that ncRAN might represent a novel prognostic indicator, a biomarker for the early detection of metastasis and a target for gene therapy in CRC.