A Study On The Formation Mechanism And Therapy Of Gefitinib Resistance In Non-small Cell Lung Cancer On Bioinformatics

Background and Objective:Non-small cell lung cancer(NSCLC)is the most common type of lung cancer,accounting for 80-90%of lung cancers.For patients with epidermal growth factor receptor(EGFR)mutation-positive NSCLC,epidermal growth factor receptor tyrosine kinase inhibitors(EGFR TKIs)provide a favorable therapeutic effect.Gifetinib is currently the most important first-generation EGFR TKI for patients with EGFR mutant NSCLC.However,the vast majority of patients develop acquired resistance within a year or so.About 50%of patients with acquired resistance were found to have a T790M mutation,and some other patients were reported to have mutations in activation,histology,or phenotypic transformation of alternative or downstream pathways,but still 15%of patients could not be attributed to the above mechanisms.Therefore,the discovery of new molecular mechanisms and potential reversal drugs for gefitinib resistance has become an urgent issue.The aim of this study was to explore the gene expression changes and biological mechanism of gefitinib-resistant non-small cell lung cancer cell line based on open data,and to investigate the effect of dasatinib in combination with gefitinib on reversing gefitinib-resistant HCC827 lung cancer cells according to the results of drug screening.This study provided bioinformatics basis for the causes and treatment of gefitinib resistance in NSCLC cancer cell lines.Methods:In this study,two datasets,GSE122005 and GSE123066,were downloaded and grouped from the GEO(Gene Expression Omnibus)database.Differentially expressed genes were screened using R software.ClusterProfiler R package was used to perform enrichment analysis and visualization of differentially expressed genes using Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)to identify relevant highly expressed gene pathways.Based on this,the STRING database and Cytoscape software were used to construct protein interaction networks(PPI)and analyze the key genes and biological processes of the network.Finally,the CMap website was used to identify drugs associated with drug resistance by differential genes in cell lines.In the following experiments,HCC827 cells and gefitinib-resistant HCC827/GR cells were treated with different concentrations of gefitinib and dasatinib alone or in combination,and the reversal effect of dasatinib combined with gefitinib on gefitinib-resistance was detected by CCK-8 assay,tumor cell invasion assay and cell scratch assay.Results:According to the analysis of the two chipsets,there are 1715 differential genes in GSE122005,including 923 up-regulated and 792 down-regulated,and 806 differential genes in GSE123066,including 327 up-regulated and 479 down-regulated.In both chipsets.42 genes were overexpressed and 83 genes were overexpressed.The results of GO showed that the structures and functions involved in differentially expressed genes were mainly concentrated in exosomes and gene forward regulation,and the molecular functions were mainly in protein binding and GTP binding.KEGG analysis showed that differentially expressed genes were mainly involved in extracellular adhesion factor signaling pathway and Rapl signaling pathway,etc.The top 30 hub genes of the network regulatory center were obtained through STRING database and Cytoscape analysis,and verified in Kaplan Meier-plotter website.It was found that the high expression of GNG4 and STC2 genes was negatively correlated with overall survival,and the high expression of VIM and RAC2 genes was positively correlated with overall survival.Seven drugs including IB-MECA,dasatinib,dubinidine,phensuximide,6-aminochrysene,fulvestrant and torasemide were associated with gefitinib resistance in CMap database.CCK8 analysis showed that dasatinib combined with gefitinib overcame the resistance of HCC827 lung cancer cells to gefitinib.Tumor cell invasion assay and cell scratch assay showed that the migration and invasion ability of HCC827/GR cells decreased after treatment with dasatinib combined with gefitinib.Conclusions:In this study,we found that the formation of drug resistance in human non-small cell lung cancer cell lines was strongly correlated with CAMs signaling pathway and Rapl signaling pathway.These two mechanisms can be explored for the mechanism of resistance to gefitinib in non-small cell lung cancer cells.We identified four hub genes associated with gefitinib resistance in NSCLC,including GNG4,STC2,VIM,and RAC2.They work primarily by affecting epithelial-interstitial transformation(EMT).The three drugs IB-MECA,dasatinib,and fulvestrant can be emphasized in the biological study of gemfitinib resistance.The results of the follow-up study showed that the combination of dasatinib and gefitinib had a synergistic effect to restore the sensitivity of HCC827/GR cells to gefitinib,which verified the results of our bioinformatics analysis.