Despite substantial advancements in the diagnosis and therapeutic interventions for THCA, misdiagnoses still afflict a considerable number of individuals. With THCA diagnoses increasingly affecting a younger demographic, there exists an imperative demand for the discovery of dependable biomarkers to enable earlier-stage diagnosis and treatment monitoring. In the present study, our initial endeavor was to establishe an intricate mRNA-miRNA-mRNA network, coupled with an exploration of DNA methylation expression pattern in PTC using rigorous bioinformatics analyses.We systematically scrutinized the functions of potential competing endogenous RNAs (ceRNAs) through pathway enrichment and survival analyses. 8 genes were identified significantly related with THCA prognosis. Finally, we conducted functional assays that affirm ITGA2 contributed to the tumorigenesis of PTC, Moreover, we investigated how the methylation levels of ITGA2 may exert a regulatory influence on the development of THCA.
Recent investigations have uncovered pivotal genes and constructed ceRNA regulatory networks across a spectrum of cancers, including bladder cancer15, gastric cancer16, breast cancer17, and lung adenocarcinoma18. Wang et al. have established MMP9/ITGB1-miR-29b-3p-HCP5 network in pancreatic cancer, offering valuable prognostic biomarkers for patients with pancreatic cancer19. Meanwhile,Zheng et al. demonstrated that the existence STARD13-correlated ceRNA network that curbs the stemness of breast cancer through inhibiting YAP/TAZ activation via Hippo and Rho-GTPase/F-actin signaling20,proposing a novel therapeutic strategy for targeting stemness. In the current study, we constructed an mRNA-miRNA-mRNA ceRNA interactive network by integrated bioinformatics analysis and obtained 51 genes through the intersection of ceRNAs and methylated genes. To further elucidate the function of these genes, we conducted comprehensive functional enrichment analyses. Our KEGG pathway analysis uncovered 8 genes (FN1, ACTIN1, TNC, ITGA2, TIAM1, TGFB1, CLDN1 and TCF7L1) enriched in pathways associated with ECM-receptor interaction, proteoglycans, amoebiasis, tight junction, and pathway in cancer. It is well-acknowledged that extracellular matrix interaction and proteoglycans play essential roles in cancer tumorigenesis and progression21,22. Therefore, we have established a linkage between these eight genes and the regulation of migration and metastasis of THCA. Among these genes, FN1, ITGA2, and TIAM1 have been previously documented as contributors to cancer progression 23–25. Notably, the overexpression of ITGA2 has been shown to significantly enhance proliferation and invasion of various cancer cells23. In addition, Liu et al. revealed that TIAM1 promotes EMT and and metastasis in THCA through the Wnt/β-catenin pathway mediated by Rac124. Furthermore, Cai et al. demonstrated that FN1 promoted cell proliferation, migration, and invasion while inhibiting apoptosis in colorectal cancer, primarily through its interaction with ITGA526. These results substantiate and support the viability of our study to some extent.
To further validate the findings from our bioinformatics analysis, we opted to perform experimental investigations on genes enriched in the top KEGG pathway, specifically FN1, ITGA2, and TIAM1, to perform experiments. ITGA2, as the alpha subunit of a transmembrane receptor for collagens, holds a pivotal role in mediating cell adhesion and interactions with the extracellular matrix27. The overexpression of ITGA2 has been linked to enhanced cell proliferation, migration, and invasion in various cancer types, including pancreatic cancer, prostate cancer, hepatocellular carcinoma, and gastric cancer23,28–30. In alignment with these previous studies, our analysis revealed elevated expression level of ITGA2 in PTC relative to adjacent normal thyroid tissue, its status as an oncogene in PTC.
In addition, knockout of ITGA2 significantly inhibited cell proliferation, migration, and invasion of PTC, demonstrating that ITGA2 may plays an essential role on THCA carcinogenesis and suggesting that it may serve as a biomarker for PTC patients. A recent study demonstrated that Ropivacaine, a local anesthetic, can effectively curb cell proliferation, invasion, migration, and promote apoptosis in PTC cells by regulating ITGA2 expression 11.This substantiates our findings and underscores the significance of our study providing credible biomarkers for the treatment of thyroid cancer patients. Additionally, we made a simultaneous discovery that the methylation levels of ITGA2 exhibited a negative correlation with its expression level. Our methylation-specific MSP assay revealed that the ITGA2 promoter displayed hypomethylated in TPC-1 cells, which significantly contrasted with the situation in Nthy-ori3-1 cells. This discovery holds great potential for shedding light on the biological role of ITGA2 in THCA, as well as corresponding mechanism.
In conclusion, our study has successfully established a novel ceRNA network of THCA. We have pinpointed eight candidate genes that may serve as potential therapeutic biomarkers for individuals diagnosed with thyroid cancer. Furthermore, we have substantiated the significance of ITGA2, which will deeper the understanding of the carcinogenesis and progression of THCA. However, it is important to note that our study has not unveiled the intricate molecular mechanism through which ITGA2 promotes the malignant phenotypes of THCA. Further investigations will necessitate further analyses and experiments to address this knowledge gap.