Microarray Profiling of TGF-β1-Induced Long Non-Coding RNA Expression Patterns in Human Lung Bronchial Epithelial BEAS-2B Cells

Abstract

Background/Aims: TGF-β1 mediated radiation-induced bystander effects (RIBE) have been linked with malignant transformation and tumorigenesis. However, the underlying mechanisms are not fully understood. Methods: To reveal new molecules of regulatory functions in this process, lncRNA microarray was performed to profile both lncRNA and mRNA expression patterns in human lung bronchial epithelial BEAS-2B cells treated with TGF-β1 at a concentration measured in the medium conditioned by directly irradiated BEAS-2B cells. The potential functions of the differentially expressed lncRNAs were predicted by GO and KEGG pathway analyses of their co-expressed mRNAs. Cis- and trans-regulation of the lncRNAs were analyzed and the interaction networks were constructed using Cytoscape. qRT-PCR was conducted to validate the results of microarray profiling. CCK-8 assay was employed for functional validation of 3 identified lncRNAs. Results: 224 lncRNAs were found to be dysregulated, among which 6 lncRNAs were chosen for expression validation by qRT-PCR assay. Pathway analyses showed that differentially expressed lncRNAs are highly correlated with cell proliferation, transformation, migration, etc. Trans-regulation analyses showed that the differentially expressed lncRNAs most likely participate in the pathways regulated by four transcriptional factors, FOS, STAT3, RAD21 and E2F1, which have been identified to be involved in the modulation of oncogenic transformation, cell cycle progression, genomic instability, etc. lnc-THEMIS-2 and lnc-ITGB6-4, predicted to be regulated by STAT3 and E2F1 respectively, were found to rescue the decrease of cell viability induced by TGF-β1 treatment. Conclusion: Our findings suggest that the differentially expressed lncRNAs induced by TGF-β1 play crucial roles in the oncogenic transformation and tumorigenesis, which provide a better understanding of the underlying mechanisms related to tumorigensis induced by LD/LDR radiations.