# Multiomics Investigation of Exhausted T Cells in Glioblastoma Tumor Microenvironment: CCL5 as a Prognostic and Therapeutic Target

## TL;DR

This study explores exhausted T cells in glioblastoma and identifies CCL5 as a potential target for improving prognosis and treatment.

## Contribution

A novel set of TEX-related genes and a prognostic model for GBM, with CCL5 identified as a therapeutic target.

## Key findings

- Five hub genes (CCL5, IL18, CXCR6, FCER1G, TNFSF13B) were identified as prognostic markers in GBM.
- Low CCL5 expression in T cells correlates with reduced immune checkpoint genes and improved immune function.
- Palbociclib shows potential as a therapeutic agent targeting CCL5 in GBM.

## Abstract

Glioblastoma multiforme (GBM) is a common malignancy with poor prognosis, and exhausted T (TEX) cells, a subset of T cells characterized by progressive loss of effector functions, play a critical role in its progression. This study aimed to investigate the impact of TEX-related genes on immune function, prognosis, and drug sensitivity in GBM through multiomics analysis. Initially, we identified a novel set of TEX-related genes specific to GBM and screened hub genes (CCL5, IL18, CXCR6, FCER1G, TNFSF13B) using conventional statistical methods combined with machine learning. A prognostic risk model was subsequently constructed based on TCGA data and validated in the CGGA cohort. Single-cell and pharmacogenomic analyses revealed significant differences in tumor microenvironment composition and drug sensitivity between risk groups. Notably, Palbociclib emerged as a potential therapeutic agent targeting the novel discovered biomarker CCL5. RT-qPCR results showed that T cells with low CCL5 expression exhibited reduced expression of immune checkpoint-related genes (PD1, TIM3, LAG3) and increased expression of CD28, suggesting enhanced immune function. In conclusion, our findings highlight five hub genes as prognostic markers that could stratify GBM patients with different immune landscapes and levels of drug sensitivity. Furthermore, experimental results suggest that low CCL5 expression could alleviate T cell exhaustion and represent a promising therapeutic target, offering new strategies for improving GBM prognosis.