POLE2 facilitates the malignant phenotypes of glioblastoma through promoting AURKA-mediated stabilization of FOXM1.

Glioblastoma (GBM) is a type of brain cancer with high morbidity and mortality worldwide. The clinical significance, biological roles, and underlying molecular mechanisms of DNA poly ε-B subunit (POLE2) in GBM were investigated in the study. Firstly, the Cancer Genome Atlas (TCGA) database found that POLE2 was highly expressed in GBM. Immunohistochemistry (IHC) results further confirmed that POLE2 was abnormally elevated in GBM. In addition, loss-of-function assays revealed that POLE2 knockdown could inhibit the malignant behaviors of GBM, especially reduce cell viability, weaken cell clone formation, enhance the sensitivity of apoptosis, restrain migration and inhibit epithelial-mesenchymal transition (EMT) in vitro. In vivo experiments further clarified the suppressive effects of reduced POLE2 expression on tumors. Mechanically, POLE2 knockdown promoted the ubiquitination as well as reduced the stability of Forkhead transcription factor (FOXM1), which is a known tumor promotor in GBM, through Aurora kinase A (AURKA). Moreover, the knockdown of FOXM1 could weaken the promoting effects of POLE2 on malignant behaviors of GBM. In conclusion, our study revealed crucial roles and a novel mechanism of POLE2 involved in GBM through AURKA-mediated stability of FOXM1 and may provide the theoretical basis of molecular therapy for GBM.