Long noncoding RNA NBAT-1 suppresses tumorigenesis and predicts favorable prognosis in ovarian cancer.

Long noncoding RNA (lncRNA) has been proven to be involved in many biological processes in ovarian cancer (OC). However, the mechanism still remains unknown. In this study, we screened significantly downregulated NBAT-1, which has been proven to play a significant role in breast cancer, clear cell renal cell carcinoma, and neuroblastoma, but not in OC, in two independent datasets with relatively more samples (GSE18520 and GSE38666) from Gene Expression Omnibus. We found that lncRNA NBAT-1 was obviously downregulated in OC tissue compared to normal ovarian tissue (<0.001) which was free of OC, and the detected levels of NBAT-1 were associated with the International Federation of Gynecology and Obstetrics stage and tumor size guidelines. Moreover, it has been shown that lower levels of NBAT-1 predict poor outcomes of OC. In order to investigate the functional role of NBAT-1, pcDNA-NBAT-1 and empty vector were transfected into TOV112D and OVCAR-3 cell lines. Overexpressed NBAT-1 significantly inhibited cell proliferation, invasion, and migration in both TOV112D and OVCAR-3 cell lines. Finally, Western blot assay indicated that NBAT-1 may exert its function by targeting the ERK1/2 and AKT signaling pathways. In addition, tumor formation growth assay showed that overexpressed NBAT-1 significantly suppresses tumor growth in vivo. In conclusion, our study suggests that NBAT-1 acts as an anti-oncogene in the development of OC.