LncRNA FENDRR-mediated tumor suppression and tumor-immune microenvironment changes in non-small cell lung cancer

Background: Long noncoding RNAs (lncRNAs) play a key role in the development and progression of many cancer types, including lung cancer. The objective of this study is to examine the function and molecular mechanism of lncRNAs involved in non-small cell lung cancer (NSCLC). Methods: First, 7 lung cancer-related differentially expressed LncRNAs were screened from 2 genomic profiling datasets. Of these lncRNAs, FOXF1 adjacent noncoding developmental regulatory RNA (FENDRR) was found to be the only one that was both significantly down-regulated in the patients with advanced pathology and negatively correlated with prognosis. Thus, lncRNA FENDRR was further studied in this project. Clinical correlation analysis was further conducted in the GSE30219 dataset and 73 paired lung cancer and noncancerous tissues stored in our lab; Subsequently, we evaluated FENDRR coding potential with the Phylogenetic Codon Substitution Frequencies (PhyloCSF), Coding-Potential Assessment Tool (CPAT), and Coding Potential Calculator (CPC) online analytical tool. The cell growth ability was measured by CCK8 assay and clonogenicity assay, the metastatic capacities were evaluated using Transwell migration and invasion assays. Mechanistically, we analyzed the correlation of FENDRR function in NSCLC with immune response by utilizing The Cancer Genome Atlas (TCGA) data. Results: Results indicated a negative clinical correlation of FENDRR. Coding potential analysis showed FENDRR as a noncoding RNA. Elevated expression of FENDRR led to cell growth arrest, inhibition of proliferative ability, declined migration and invasion potential of NSCLC cells in vitro. Mechanistically, we discovered that FENDRR expression might be involved in aberrant immune response regulation. Conclusions: Taken together, our results provide a greater understanding of lncRNA FENDRR as a tumor suppressor with respect to tumor-immune interactions in NSCLC.