DDX17 modulates the expression and alternative splicing of genes involved in apoptosis and proliferation in lung adenocarcinoma cells

Abstract

Background The DEAD-box RNA-binding protein (RBP) DDX17 has been found to be involved in the tumorigenesis of many types of cancers. However, the role of DDX17 in lung adenocarcinoma (LUAD) remains unclear. Methods We silenced DDX17 expression in A549 LUAD cells by small interfering RNA (siRNA). Cell proliferation and apoptosis assays were performed to explore the functions of DDX17. Knockdown of DDX17 by siRNA significantly inhibited proliferation and induced apoptosis in A549 cells. We used high-throughput RNA sequencing (RNA-seq) to identify differentially expressed genes (DEGs) and alternative splicing (AS) events in DDX17 knockdown LUAD cells. Results DDX17 knockdown increased the expression levels of proapoptotic genes and decreased those of proproliferative genes. Moreover, the DDX17-regulated AS events in A549 cells revealed by computational analysis using ABLas software were strongly validated by quantitative reverse transcription–polymerase chain reaction (RT–qPCR) and were also validated by analysis of The Cancer Genome Atlas (TCGA)-LUAD dataset. These findings suggest that DDX17 may function as an oncogene by regulating both the expression and AS of proliferation- and apoptosis-associated genes in LUAD cells. Our findings may offer new insights into understanding the molecular mechanisms of LUAD and provide a new therapeutic direction for LUAD.

Identification of related-genes of T cells in lung tissue of chronic obstructive pulmonary disease based on bioinformatics and experimental validation

“…Studies have shown that DDX17 regulates autophagy and actincytoskeleton remodeling in lung adenocarcinoma through MAGEA6 andMYL9 signaling 46 . DDX17 accelerates lung cancer progression by promoting reduced apoptosis 47 . At present, research on DDX17 has focused on cancer, and there have been relatively few studies of on-tumor diseases, especially chronic obstructive pulmonary disease 48 , 49 .…”

Identification of Related-Genes of T cells in Lung Tissue of Chronic Obstructive Pulmonary Disease Based on Bioinformatics and Experimental Validation

“…COPD is the third leading cause of death worldwide,and immunotherapy has been a focus of research.For instance,the macrolide drug erythromycin,inhibits dendritic cell-mediated CD4+T cell polarization to Th17 cells in vivo and in vitro through the CD40/CD40L pathway,partially limiting the in ammatory responses of emphysema 31 .Rapamycin,a novel macrolide immunosuppressant,inhibits mTOR-induced CD8+T cells in the lung tissue of a mouse emphysema model exposed to chronic cigarette smoke 32 .Although immunotherapy for COPD has demonstrated the effective inhibitory effect of macrolides on T cells,the current treatment options are less effective.The signaling pathways involved in T cell regulation under chronic cigarette smoke exposure have yet to be fully elucidated.Considering the pathogenesis of T cells and as blocking the immune responses of T cells can effectively control the progression of COPD,we analyzed the microarray data of COPD from the GEO database to obtain DEGs and modules most relevant to the COPD disease phenotype.ScRNA-seq analysis acquired DEGs of T cells between normal and COPD groups.The GO,GSEA and KEGG analyses of DEGs and DEGs of T cells showed that different signaling pathways are involved.FOXO1 and DDX17 were identi ed by the intersection of DEGs,genes of the red module and DEGs of T cells.The relative mRNA and protein expression levels of FOXO1 and DDX17 were veri ed by RT-qPCR and Western Blot in emphysema mouse lung tissue. FOXO1 a member of the Forkead transcription factor family,regulates cell stability,and the cell cycle and coordinates the response to various environmental changes 33,34 .There is evidence suggesting that FOXO1 protein expression levels are increased in the quadriceps muscle of COPD patients with muscle atrophy [35][36][37][38] .The mRNA expression levels of SIRT1 and FOXO1 in the peripheral blood of patients with COPD have been positively correlated with physical exercise 39 .However,there are also results that are inconsisitent with current studies.For example,AMPK compromised epithelial cell apoptosis induced by cigarette smoke extract exposure through FOXO1-induced ORP150 40 .FOXO1 expression is downregulated in the miRNA-mRNA signaling pathway in the blood of COPD patients 41 .The inconsistency of the above results may be due to differences in the severity of COPD in patients,individual animals and experimental conditions.DDX17,a member of the DEAD-box RNA helicases(DDX) family,plays a crucial role in the pathophysiological changes and metabolism of RNA 42 .Studies have shown that DDX17 regulates autophagy and actin cytoskeleton remodeling in lung adenocarcinoma through MAGEA6 and MYL9 signaling 43 .DDX17 accelerates lung cancer progression by promoting reduced apoptosis 44 .At present,research on DDX17 has focused on cancer,and there have been relatively few studies of on-tumor diseases,especially chronic obstructive pulmonary disease 45,46 .…”

DEAD-Box Helicase 17 Promotes Amyloidogenesis by Regulating BACE1 Translation

“…The DEAD-box RNA helicases are the largest family of RNA helicases. They play an important role in gene expression and RNA metabolism ranging from pre-mRNA splicing, mRNA export and decay and translation initiation, to ribosome biogenesis [61,62]. DDX17, in particular, is involved in various types of human diseases [24,25,29].…”