ABSTRACT
Dysregulation of long noncoding RNA (lncRNA) is known to be involved in numerous human diseases, including lung cancer. However, the precise biological functions of most lncRNA remain to be elucidated. Here, we identified a novel up-regulated lncRNA, LINC01436 (RefSeq: NR_110419.1), in non-small cell lung cancer (NSCLC). High expression of LINC01436 was significantly associated with poor overall survival. Notably, LINC01436 expression was transcriptionally repressed by E2F6 under normoxia, and the inhibitory effect was relieved in a hypoxic microenvironment. Gain- and loss-of-function studies revealed that LINC01436 acted as a proto-oncogene by promoting lung cancer cell growth, migration and invasion in vitro. Xenograft tumor assays in nude mice confirmed that LINC01436 promoted tumor growth and metastasis in vivo. Mechanistically, LINC01436 exerted biological functions by acting as a microRNA (miR)-30a-3p sponge to regulate the expression of its target gene EPAS1. Our findings characterize LINC01436 as a new hypoxia-sensitive lncRNA with oncogenic function in NSCLC, suggesting that LINC01436 may be a potential biomarker for prognosis and a potential target for treatment.
Subject(s)
Carcinoma, Non-Small-Cell Lung/genetics , E2F6 Transcription Factor/metabolism , Gene Expression Regulation, Neoplastic , Lung Neoplasms/genetics , MicroRNAs/metabolism , Oncogenes , RNA, Long Noncoding/metabolism , Tumor Hypoxia/genetics , Animals , Base Sequence , Basic Helix-Loop-Helix Transcription Factors/metabolism , Carcinoma, Non-Small-Cell Lung/pathology , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation/genetics , Humans , Lung Neoplasms/pathology , Male , Mice, Inbred BALB C , Mice, Nude , MicroRNAs/genetics , Models, Biological , Neoplasm Invasiveness , Neoplasm Metastasis , Proto-Oncogene Mas , RNA, Long Noncoding/genetics , Survival Analysis , Up-Regulation/geneticsABSTRACT
Long non-coding RNAs (lncRNAs) have been involved in the process of cancer occurrence, progression, and treatment. Lung cancer-related lncRNAs are still an emerging field, thus we sought to identify novel functional lncRNAs as candidate targets in lung cancer. Here, we identified one novel lncRNA, MUC5B-AS1 (Ensembl: ENST00000532061.2). MUC5B-AS1 was upregulated in lung adenocarcinoma tissues compared with normal lung tissues. Moreover, MUC5B-AS1 promoted lung cancer cell migration and invasion in vitro and promoted lung cancer cell metastasis in vivo. MUC5B-AS1 and its cognate sense transcript MUC5B were highly co-expressed and mutually regulated in lung adenocarcinoma. Mechanistically, MUC5B-AS1 promoted cell migration and invasion by forming an RNA-RNA duplex with MUC5B, thereby increasing MUC5B expression levels in lung adenocarcinoma. The high expression of MUC5B was significantly associated with poor outcomes in lung adenocarcinoma. Our findings highlight MUC5B-AS1 functions as an oncogenic lncRNA in tumor metastasis and implicate MUC5B-AS1 as an attractive candidate target for lung adenocarcinoma treatment.
