Dysregulation of the cAMP Signaling Pathway Mediated by Shared Hub Genes: Diagnostic, Prognostic, and Therapeutic Insights into Thyroid Cancer and Graves' Disease

Background: Graves' disease and Thyroid cancer share overlapping molecular mechanisms that may reveal potential biomarkers and therapeutic targets. Identifying shared hub genes can provide insights into disease progression and improve diagnosis and treatment strategies. Methodology: Gene expression profiles from Graves' disease (GSE71956) and thyroid cancer (GSE153659) datasets were analyzed to identify differentially expressed genes (DEGs) using the limma package. Common DEGs were identified through cross-dataset comparison, and hub genes were determined based on the degree method. CD44, RHOC, HCN4, and MYH10 hub genes were validated using RT-qPCR in thyroid cancer and normal cell lines and analyzed for functional roles via siRNA-mediated knockdown experiments. miRNA regulators of hub genes were predicted using TargetScan and validated with RT-qPCR. Promoter methylation, mutation, and copy number variation (CNV) analyses were conducted using OncoDB and cBioPortal. Prognostic significance was assessed using the cSurvival and GENT2 databases. Functional enrichment analysis was performed using DAVID, GeneMANIA, and GSCA. miRNA target prediction was carried out with TargetScan, and expression correlation analysis was performed using GEPIA2. Results: Twenty-three common DEGs were identified, with CD44, RHOC, HCN4, and MYH10 emerging as key hub genes. RT-qPCR showed significant (p < 0.001) upregulation of these genes in thyroid cancer cell lines. Functional analysis linked these genes to cAMP signaling and EMT pathways, with promoter hypomethylation, CNV amplifications, and mutations contributing to their dysregulation. CD44 and RHOC knockdown significantly (p < 0.01) reduced proliferation, colony formation, and migration in SW579 cells. Predicted tumor-suppressive miRNAs, including hsa-miR-199a-3p and hsa-miR-455-3p.2, were significantly (p < 0.0001) downregulated in thyroid cancer. Conclusion: CD44, RHOC, HCN4, and MYH10 were identified as shared hub genes between Graves' disease and thyroid cancer, with functional roles in oncogenic pathways. Their diagnostic and therapeutic potential offers novel insights into thyroid disease pathogenesis.