Identification of crucial regulatory relationships between long non-coding RNAs and protein-coding genes in lung squamous cell carcinoma.

PURPOSE: This study aimed to analyze the relationships of long non-coding RNAs (lncRNAs) and protein-coding genes in lung squamous cell carcinoma (LUSC).

METHODS: RNA-seq data of LUSC deposited in the TCGA database were used to identify differentially expressed protein-coding genes (DECGs) and differentially expressed lncRNA genes (DE-lncRNAs) between LUSC samples and normal samples. Functional enrichment analysis of DECGs was then performed. Subsequently, the target genes and regulators of DE-lncRNAs were predicted from the DECGs. Additionally, expression levels of target genes of DE-lncRNAs were validated by RT-qPCR after the silence of DE-lncRNAs.

RESULTS: In total, 5162 differentially expressed genes (DEGs) were screened from the LUSC samples, and there were seven upregulated lncRNA genes in the DEGs. The upregulated DECGs were enriched in GO terms like RNA binding and metabolic process. Meanwhile, the downregulated DECGs were enriched in GO terms like cell cycle. Furthermore, the lncRNAs PVT1 and TERC targeted multiple DECGs. PVT1 targeted genes related to cell cycle (e.g. POLA2, POLD1, MCM4, MCM5 and MCM6), and reduced expression of PVT1 decreased expression of the genes. TERC regulated several genes (e.g. NDUFAB1, NDUFA11 and NDUFB5), and reduced expression of TERC increased expression of the genes. Additionally, PVT1 was regulated by multiple transcription factors (TFs) identified from DECGs, such as HSF1; and TERC was modulated by TFs, such as PIR.

CONCLUSION: A set of regulatory relationships between PVT1 and its targets and regulators, as well as TERC and its targets and regulators, may play crucial roles in the progress of LUSC.