Analysis of the Mechanism Underlying Radiotherapy Resistance Caused by Oligodendroglia Cells in Glioblastoma by Applying the Single-cell RNA Sequencing Technology.

Background: Glioblastoma (GBM) is an aggressive malignancy. The inherent resistance of GBM to radiotherapy poses great challenges for clinical treatment.

Objectives: The primary objective of this study is to explore the molecular mechanisms of radiotherapy resistance in GBM and identify the key influencing factors that contribute to this phenomenon.

Methods: The single-cell RNA sequencing (scRNA-seq) data of GBM were downloaded from the Gene Expression Omnibus (GEO) database. Cells were clustered using the Seurat R package, and the clusters were annotated using the CellMarker database. Pseudotime analysis was conducted using Monocle2. Marker scores were calculated based on the RNA-seq data of GBM from the UCSC database, and the enrichment of Hallmark gene sets was measured with the AUCell package. Furthermore, the most frequently mutated genes were identified using the simple nucleotide variation data from The Cancer Genome Atlas (TCGA) applying the maftools package.

Results: This study identified two oligodendrocyte subsets (ODC3 and ODC4) as radiotherapy-resistant groups in GBM. Enrichment and Pseudotime analysis revealed that the inflammatory response and immune activation pathways were enriched in ODC3, while the cell division and interferon response pathways were enriched in ODC4. The enrichment scores of hallmark gene sets further confirmed that ODC3 and ODC4 subpopulations developed radiotherapy resistance via distinct molecular mechanisms. Analysis of gene mutation frequencies showed that TP53 exhibited the most significant change in mutation frequency, indicating that it was an important risk factor involved in radiotherapy resistance in GBM.

Conclusion: We identified two ODC subpopulations that exhibited resistance to radiotherapy, providing a new perspective and potential targets for personalized treatment strategies for GBM.