RESUMO
Background: Deregulation of long noncoding RNAs (lncRNAs) was considered one of the main characteristics of several human cancers. However, detailed genome-wide expression and functional significance studies of lnc RNAs in lung adenocarcinoma are still limited. This study aims to discover a new lncRNA that may play an important role in regulating the pathogenesis of lung adenocarcinoma (ADC). Methods: We conducted a comprehensive analysis of three Gene Expression Omnibus (GEO) microarray datasets and TCGA datasets. Differentially expressed lncRNAs between ADC and normal tissues were screened and verified using Gene Expression Profiling Interactive Analysis (GEPIA). Moreover, Kaplan-Meier plotter was used to construct the gene prognosis profile. The downstream targets of miRNA and related functional pathways were predicted and validated. Results: With microarray gene expression analysis, we found that only lncRNAs-PCAT6 was commonly upregulated among four datasets, and four lncRNAs (LINC00968, PGM5-AS1, LHFPL3-AS2 and SFTA1P) were significantly downregulated in the ADC samples as compared to the normal tissues. Meanwhile, for LHFPL3-AS2, high-risk patients showed better overall survival (HR=0.6 or 0.62; P < .0001 or P = 0.0014), overall survival from TCGA datasets (HR=0.72; P = 0.015) and recurrence-free survival (HR=0.72; P = 0.015). Then, LHFPL3-AS2 was predicted to bind to two miRNAs, miR-127-5p and miR-424-5p. Finally, validation and functional enrichment analysis of the downstream key mRNAs showed significant enrichment in some cancer-related pathways, such as cell adhesion in cancer and small cell lung cancer. Conclusions: Taken together, our study indicated that LHFPL3-AS2 was associated with tumorigenesis, and it could be used as a useful biomarker in the diagnosis, prognosis and treatment of ADC.