Construction and analysis of expression profile of exosomal lncRNAs in pleural effusion in lung adenocarcinoma

BACKGROUND: Lung adenocarcinoma (LUAD) is a highly malignant tumor with a very low five‐year survival rate. In this study, we aimed to identify differentially expressed long‐chain non‐coding RNA (lncRNAs) and mRNAs from benign and malignant pleural effusion exosomes. METHODS: We used gene microassay and quantitative real‐time reverse transcription polymerase chain reaction (RT‐qPCR) to detect and verify differentially expressed mRNAs and lncRNAs in benign and malignant pleural effusion exosomes. Gene Ontology (GO) functional significance and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway significance enrichment analyses were performed to identify the difference in biological processes and functions between different mRNAs. We selected the lncRNA ZBED5‐AS1 with an upregulated differential fold of 3.003 and conducted a preliminary study on its cellular function. RESULTS: Gene microassay results revealed that 177 differentially expressed lncRNAs were upregulated, and 215 were downregulated. The top 10 upregulated were FMN1, AL118505.1, LINC00452, AL109811.2, CATG00000040683.1, AC137932.1, AC008619.1, AL450344.1, AC092718.6, and ZBED5‐AS1. The top 10 downregulated were TEX41, G067726, JAZF1‐AS1, AC027328.1, AL445645.1, AL022345.4, AC008572.1, AC123777.1, AC093714.1, and PHKG1. For the mRNAs, 79 were upregulated, and 123 were notably downregulated. GO analysis revealed that the upregulated differential mRNAs were mainly involved in “cellular response to acidic pH” (biological processes), “endoplasmic reticulum part” (cellular components), and “at DNA binding, cyclase activity” (molecular functions). KEGG pathways were found to be related to V. cholerae infection, Parkinson's disease, and cell adhesion molecules. RT‐qPCR showed that ZBED5‐AS1 was highly expressed in LUAD tissues, cells, and benign and malignant pleural fluid exosomes. Overexpression of ZBED5‐AS1 could significantly promote the proliferation, migration, invasion, and colony formation of LUAD cells, and knockdown had the opposite consequence. CONCLUSION: The pleural effusion exosomes from patients with LUAD include several improperly expressed genes, and lncRNA‐ZBED5‐AS1 is a new biomarker that aids in our understanding of the occurrence and progression of LUAD.