Grade-Specific Prognostic Roles of MGMT and TERT in Glioma: Integrated Bioinformatics Analysis and Functional Validation

Background O6-methylguanine-DNA-methyltransferase (MGMT) expression and promoter methylation influence high-grade glioma survival, while telomerase reverse transcriptase (TERT) plays a key prognostic role. However, their combined effects on glioma prognosis remain unexplored. Methods This study analyzed LGG and GBM samples from TCGA, with transcriptional and proteomic data from TCGA and CPTAC supplemented for expression verification. Survival analyses were conducted using R packages, with Kaplan-Meier curves and Log-rank tests assessing risk groups. To investigate functional roles, in vitro experiments were performed in glioma cells with MGMT overexpression and/or TERT knockdown. Gene manipulation efficiency was validated by qRT-PCR, and cell proliferation, migration, and invasion were assessed using CCK-8, wound healing, and Transwell assays. Results In grade II gliomas, MGMT, TERT, and their combined effects showed no survival association. In grade III, lower TERT expression correlated with longer survival, while MGMT and the combined score were not prognostic. In grade IV, MGMT and the combined score were significantly linked to survival. In vitro experiments confirmed successful transfection by qRT-PCR. Functional assays revealed that TERT knockdown significantly inhibited cell proliferation, migration, and invasion, whereas MGMT overexpression alone had no significant effect on these malignant phenotypes. The combined intervention produced inhibitory effects comparable to TERT knockdown alone, suggesting TERT as a key functional driver in glioma progression. Conclusion MGMT and TERT impact glioma progression differently, with TERT playing a direct functional role in promoting tumor cell invasion. These findings highlight their distinct potential as prognostic markers and therapeutic targets in different glioma grades.