Upregulated NNT-AS1, a long noncoding RNA, contributes to proliferation and migration of colorectal cancer cells in vitro and in vivo

// Qian Wang 1 , Lei Yang 3 , Xin Hu 1 , Yuliang Jiang 1 , Yizhang Hu 1 , Zhe Liu 1 , Jian Liu 3 , Tao Wen 3 , Yingmin Ma 2 , Guangyu An 1 , Guosheng Feng 1 1 Department of Oncology, Affiliated Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China 2 Department of Respiratory Medicine, Affiliated Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China 3 Medical Research Center, Affiliated Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China Correspondence to: Guosheng Feng, email: fengguoshengcyh@163.com Guangyu An, email: anguangyucyh@163.com Yingmin Ma, email: mayingmincyh@163.com Keywords: long non-coding RNA, NNT-AS1, colorectal cancer, MAPK/Erk, biomarker Received: April 17, 2016 Accepted: November 21, 2016 Published: December 09, 2016 ABSTRACT The expression patterns of the long non-coding RNA Nicotinamide Nucleotide Transhydrogenase-antisense RNA1 (NNT-AS1) have not been investigated in the context of cancer. In this study, we aim to investigate the NNT-AS1 expression level in colorectal cancer (CRC) patients and its potential roles in tumor biology. We measured the expression of NNT-AS1 in 70 paired tumor tissues and adjacent normal tissues. NNT-AS1 was expressed higher in tumor tissues than that in adjacent noncancer tissues, and higher expression of NNT-AS1 was significantly correlated with lymph node metastasis (Yes vs. No, P=0.004), TNM stage (I/II vs. III/IV, P=0.004), vessel invasion (Yes vs. No, P=0.002) and differentiation (well and moderate vs. poor, P=0.008). Multivariate analyses revealed that NNT-AS1 expression was an independent predictor of overall survival (P=0.0174) and progression free survival (P=0.0132) for CRC. Knockdown of NNT-AS1 using small interfering RNA (siRNA) significantly impaired CRC cell proliferation, migration and invasion in vitro and silencing NNT-AS1 also suppressed tumor growth and metastasis in nude mice. The western blot experiments revealed that silencing NNT-AS1 inhibited epithelial-mesenchymal transition (EMT) and inactivated MAPK/Erk signaling pathway in CRC cell lines. In conclusion, our studies implied that NNT-AS1 may involve in the development and progression of CRC via its regulation of cell proliferation, migration, and invasion by NNT-AS1-mediated activating of MAPK/Erk signaling pathway and EMT. NNT-AS1 may be a useful diagnostic and prognostic biomarker and a potential therapeutic target in CRC patients.