Identification of an immunomodulatory lncRNA signature associated with immune cell reprogramming in high-grade glioma.

Abstract

High-grade gliomas (HGGs) are among the most aggressive brain tumors in pediatric, adolescent, and young adult (AYA) cancer patients, with a median survival of 12-15 months post-diagnosis. Their poor prognosis is driven by a highly immunosuppressive tumor immune microenvironment (TIME), which inhibits cytotoxic immune infiltration and anti-tumor response. This study investigated the involvement of long non-coding RNAs (lncRNAs) in shaping the immune phenotype of HGGs using two murine models: RCAS-PDGFb representing an immunosuppressive TME, and RCAS-BRAF V600E characterized by a signature more consistent with a pro-inflammatory TME. Transcriptomic analysis of tumor-infiltrating immune cells identified distinct lncRNA signatures associated with immunosuppressive and pro-inflammatory TMEs. Single-cell RNA sequencing and spatial transcriptomics supported context-dependent expression of these lncRNAs in high-grade glioma-associated immune cells, such as myeloid, T, and NK cells, and revealed their spatial distribution within the glioblastoma (GBM) TME. Several lncRNAs were enriched at the tumor edge and within necrotic regions in GBM patient samples, correlating with immunosuppression reprogramming and immune evasion mechanisms. These findings highlight specific immunomodulatory lncRNAs as potential players in the immunosuppressive glioma TME, and likely candidates for future studies aimed at developing novel therapeutic strategies to overcome immune suppression and improve clinical outcomes.