ID2 Inhibits Lung Adenocarcinoma Cell Malignant Behaviors Through Inhibiting the Activation of the PI3K/AKT/mTOR Signaling Pathway
Abstract Background: Lung cancer is the most common cancer and one of the main causes of cancer-related deaths, and it manifests as metastatic disease in most cases. Considering frequent gene mutation and/or signaling deregulation in lung adenocarcinoma, identifying novel factors or agents targeting these signaling pathways might be promising strategies for lung adenocarcinoma therapy. Methods: GEO datasets were analyzed to identify differentially expressed genes (DEGs) in lung adenocarcinoma. The specific effects of candidate gene overexpression or knockdown on lung adenocarcinoma cell phenotypes were examined. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) are used to connect the genomic and functional information of DEGs. The dynamic effects of candidate gene and signaling pathway agonist on lung adenocarcinoma malignant behaviors were investigated. Finally, clinical lung adenocarcinoma and adjacent non-cancerous tissues were collected and the levels of candidate gene were examined in tissue samples.Results: Inhibitor of DNA binding 2 (ID2) was identified as an aberrantly downregulated gene in lung adenocarcinoma. ID2 overexpression suppressed lung adenocarcinoma cell viability, colony formation capacity, and migration. ID2 overexpression also reduced the protein levels of N-cadherin, MMP2, MMP9, and the phosphorylation of AKT and mTOR. The PI3K/AKT/mTOR signaling agonist exerted opposite effects on lung adenocarcinoma cells to those of ID2 overexpression, and partially reversed the effects of ID2 overexpression. In tissue samples, ID2 protein levels and mRNA expression were also downregulated compared with those in adjacent non-cancerous tissues. Conclusion: ID2 exerts its tumor-suppressive effects on lung adenocarcinoma cell malignant behaviors through inhibiting the activation of the PI3K/AKT/mTOR signaling pathway. Restoring ID2 expression in lung adenocarcinoma cells might improve the curative effect of lung adenocarcinoma therapies.