Background: Glioblastomas (GB) are aggressive tumors that remain incurable, primarily due to treatment resistance and systematic relapses. These challenges are largely due to the remarkable plasticity of GB stem cells, leading to tumor cell heterogeneity and transitions between these different cell types.

Recent advances have underscored the significance of epitranscriptomic modifications of ribosomal RNA (rRNA), particularly 2’-O-methylation (2’Ome), in regulating ribosome structure and function. In GB, we hypothesize that alterations in the rRNA 2’Ome landscape may affect ribosome-mediated translational control, thereby contributing to tumor cell plasticity and heterogeneity. Such variations in rRNA 2’Ome could thus play a pivotal role in glioblastoma biology and represent promising targets for novel therapeutic strategies.

Objective: This study aims at investigating rRNA epitranscriptomics in IDH wild-type (IDHwt) and IDH mutant (IDHmut) high-grade gliomas (HGGs), with a specific focus on rRNA 2’Ome. The goal was to identify novel biomarkers and therapeutic targets by distinguishing different glioma types and analyzing variations between GB molecular subtypes (classical, mesenchymal, pro-neural) and GB cells with different degree of stemness and plasticity.

Methods: Firstly, we analyzed rRNA 2’Ome using the RiboMethSeq method across 71 HGG samples (IDHwt and IDHmut) and 9 non-tumorous controls. Focusing on GB, we examined 2’Ome variations across the three molecular subtypes using patient derived primary cell lines and compared 2’Ome status in GB cells depending on the stemness degrees, in each molecular subtype.

Results: IDHwt GB exhibited significant alterations in rRNA 2’Ome at specific sites, compared to IDHmut HGGs and non-neoplastic tissues. In addition, our detailed analysis of GBs revealed distinct rRNA 2’Ome signatures across subtypes, with differences relying on the stemness status of GB cells.

Conclusion: This study reveals alterations in the rRNA epitranscriptome in GB, providing new insights into potential therapeutic vulnerabilities that could be exploited to manage these aggressive tumors. Furthermore, investigating 2’Ome as a therapeutic target to prevent relapse and treatment resistance in GB appears promising, as preliminary data show encouraging results.