Screening And Research Of Key Genes Related To Iodine-refractory Differentiated Thyroid Cancer

Part 1.Identification of candidate genes and mechanisms associated with papillary thyroid carcinoma pathogenesis and progression by weighted gene co-expression network analysisBackground: The genes and genetic mechanisms underlying the occurrence and progression of papillary thyroid carcinoma(PTC)are still unclear.This study aimed to find candidate genes and mechanisms related to the pathogenesis and progression of PTC.Methods: RNA sequencing data of PTC and normal tissues were downloaded from The Cancer Genome Atlas database with clinical stage data to form a test,validation,and clinical-stage data matrix.First,we used the test data set to analyze differentially expressed genes(DEG)and weighted gene co-expression network(WGCNA)analysis to find those gene clusters highly correlated with PTC.We then verified the expression of genes in the interested modules using the validation matrix and Gene Expression Omnibus(GEO)database.The quantitative real-time polymerase chain reaction(q RT-PCR)was used to verify the reliability of the expression of selected genes.Five key genes(GDF15,LCN2,KCNN4,SH3BGRL3,and MMP2)were used to analyze the connection between gene expression and the American Joint Committee on Cancer stage.The upregulated and downregulated DEG,along with the modules of interest,were subjected to Gene Ontology(GO)enrichment and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment using the Database for Annotation,Visualization,and Integrated Discovery.Results: We used WGCNA analysis to find 2 modules of interest,the yellow module,which was positively associated with PTC,and the blue module,which was negatively correlated with PTC.Four genes(GDF15,LCN2,KCNN4,and SH3BGRL3)from the yellow module were determined to be highly expressed in PTC in the test data matrix and were verified in both the validation data matrix,GEO database and quantitative real-time PCR,which indicated that these 4 genes were highly correlated with the occurrence of the PTC.Furthermore,these 4 genes also had a significantly higher expression in the advanced levels of pathological T,N,and American Joint Committee on Cancer(AJCC)stage,meaning that they were correlated with the progression of PTC.Genes in the yellow module and upregulated differentially expressed genes were significantly enriched in 3 vital signaling pathways,including focal adhesion,extracellular matrix(ECM)-receptor interaction,and the PI3K-Akt signaling pathway.Conclusions: Four candidate genes(GDF15,LCN2,KCNN4,and SH3BGRL3)may be potential biomarkers for the PTC's pathogenesis and progression.Focal adhesion,extracellular matrix(ECM)-receptor interaction and PI3K-Akt signaling pathway may play an important role in the occurrence and development of PTC.Part 2.Research of the correlation between the expression of GDF15,LCN2,KCNN4 and SH3BGRL3 and radioactive iodine(RAI)treatment of papillary thyroid carcinomaBackground: Thyroid cancer is the most common endocrine malignant disease in the world,and its incidence has been increasing in recent decades.On the basis of our previous research,this study attempted to clarify GDF15,LCN2,KCNN4,and SH3BGRL3 in the occurrence and development of PTC and the prognosis of patients,and to explore the relationship between these four genes and NIS and TSHR,and to descript whether these four genes may become relevant genes for gene-targeted therapy in PTC patients.Methods: In this study,we used data from UALCAN,GEPIA,Kaplan-Meier Plotter and TIMER to analyze the four genes GDF15,LCN2,KCNN4 and SH3BGRL3 in patients with thyroid cancer using bioinformatics analysis and explored their relationship with NIS and TSHR.We used Drugbank data to screen related drugs targeting these four genes.Results: We found that the expression levels of GDF15,LCN2,KCNN4 and SH3BGRL3 were negatively correlated with NIS and TSHR.And in our study,we confirmed our previous results: through the UALCAN test,we concluded that the expression of GDF15,LCN2,KCNN4 and SH3BGRL3 in PTC was significantly higher than that of the normal cell group(p<0.05).Compared with the normal group of cells in different tumor subtypes in PTC,the expression levels of GDF15,LCN2,KCNN4 and SH3BGRL3 were also increased.However,through UALCAN,TIMER,GEPIA and Kaplan-Meier Plotter databases,we found that GDF15,LCN2,KCNN4 and SH3BGRL3 have no significant correlation with the survival of patients with thyroid cancer,and they cannot be used as prognostic indicators.We found 6 drugs that target LCN2 through Drugbank data,namely methyl nonanoate,2,3-dihydroxy-benzoic acid,carboxymycobactin S,2,3-dihydroxybenzoylserine,carboxymycobactin T and trencam-3,2-hopo,which currently are in experiment.For KCNN4,we also found 6 drugs,namely halothane,clotrimazole,quinine,procaine,trimebutine and miconazole,which have been approved by FDA.Conclusion: The expression of GDF15,LCN2,KCNN4 and SH3BGRL3 are negatively correlated with NIS and TSHR,indicating that the high expression of these four genes may play an important role in suppressing the expression of NIS and TSHR,thus reducing radioactive iodine(RAI)for papillary thyroid carcinoma.